Health surveillance in wild felid conservation: experiences with the Eurasian lynx in Switzerland

Abstract

Switzerland has become an important source of Eurasian lynx Lynx lynx for reintroduction projects in Europe. It is now widely accepted that translocations of animals are associated with a serious health risk. Therefore, the development of multidisciplinary expertise and the elaboration of veterinary protocols are needed, which require knowledge on the health status of the source population and information on potential health risks at the release site. Here, both disease cases and carriers of potentially threatening pathogens have to be taken into consideration. In Switzerland, a range of infectious agents circulate within lynx populations apparently without associated morbidity. However, genetic analyses combined with health investigations have pointed at a possible inbreeding depression. Furthermore, unexpected health issues arose in the framework of translocations. Overall, the Swiss experiences underline the necessity of long-term health surveillance of reintroduced and small isolated wildlife populations, the usefulness of well-established veterinary protocols in the framework of translocation projects, the value of multidisciplinary collaborations and of sample archives for further analyses, and the need for adaptive management based on scientific data. For a conservation programme of the Eurasian lynx on a pan-European level, procedure harmonisation should be sought.

Full text

ISSN 1027-2992
CATCAT
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The Eurasian lynx in Continental Europe
Special
Issue
I
I
N° 14 | Autumn 2021
RAUBTIERÖKOLOGIE UND WILDTIERMANAGEMENT

CATnews Special Issue 14 Autumn 2021
02
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CATnews Special Issue 14 Autumn 2021
64
MARIE-PIERRE RYSER-DEGIORGIS1*, MARINA L. MELI2, CHRISTINE BREITENMOSER-WÜRSTEN3,
REGINA HOFMANN-LEHMANN2, IRIS MARTI1, SIMONE R. R. PISANO1 AND URS BREITENMOSER3
Health surveillance in wild
felid conservation: experien-
ces with the Eurasian lynx in
Switzerland
Switzerland has become an important source of Eurasian lynx Lynx lynx for reintro-
duction projects in Europe. It is now widely accepted that translocations of animals
are associated with a serious health risk. Therefore, the development of multidis-
ciplinary expertise and the elaboration of veterinary protocols are needed, which
require knowledge on the health status of the source population and information on
potential health risks at the release site. Here, both disease cases and carriers of po-
tentially threatening pathogens have to be taken into consideration. In Switzerland,
a range of infectious agents circulate within lynx populations apparently without as-
sociated morbidity. However, genetic analyses combined with health investigations
have pointed at a possible inbreeding depression. Furthermore, unexpected health
issues arose in the framework of translocations. Overall, the Swiss experiences un-
derline the necessity of long-term health surveillance of reintroduced and small iso-
lated wildlife populations, the usefulness of well-established veterinary protocols
in the framework of translocation projects, the value of multidisciplinary collabora-
tions and of sample archives for further analyses, and the need for adaptive manage-
ment based on scientific data. For a conservation programme of the Eurasian lynx on
a pan-European level, procedure harmonisation should be sought.
Defaunation is a rather new term that aims
at raising awareness for the ongoing un-
precedented species loss worldwide (Dir-
zo et al. 2014). Attempts to counteract this
dramatic phenomenon include conservation
efforts through species reintroductions and
population reinforcement (Seddon et al. 2014).
However, it is now widely accepted that trans-
locations of animals are associated with a
serious health risk (Daszak et al. 2000, Kock
et al. 2010) because relocation of an animal
always entails relocation of a “biological
package” (the animal together with its “pas-
senger organisms”). Further health aspects
to consider in this context are stress-induced
increased susceptibility to disease and in-
juries associated with capture, transport,
and confinement in a quarantine enclosure.
Here, not only health but also animal wel-
fare requirements must be fulfilled (Kock et
al. 1999, Kock et al. 2010, Ryser-Degiorgis
2009a). Additionally, genetic considerations
are required, particularly when dealing with
populations arising from only a few individ-
uals (Trinkel et al. 2011, Brambilla et al.
2015, Pelletier et al. 2017, Grossen et al.
2018, Bozzuto et al. 2019). The development
of veterinary protocols requires knowledge
on species susceptibility to infection and di-
sease, causes of mortality and health risks,
both in the source population and at the re-
lease site, including non-infectious health
issues such as inbreeding depression. The
prerequisite to access this information is the
existence of a health surveillance programme
for the species of interest, consisting at least
in necropsies of dead animals as well as
pathogen and serological surveys, especially
at the source (Ryser-Degiorgis 2009a).
The Eurasian lynx was reintroduced to Switzer-
land in the 1970s. Meanwhile Switzerland is
considered having a great responsibility re-
garding the conservation of the Alpine lynx
population (Zimmermann et al. 2011), and the
two Swiss lynx populations (one in the Alps,
the other in the Jura Mountains; Breitenmoser
et al. 1998, Chapron et al. 2014) have become
an important source for reintroduction and re-
inforcement projects in neighbouring countries.
The aim of this article is to share the imple-
mented procedures and acquired experience in
the framework of the veterinary supervision of
lynx translocation in Switzerland (2000–2020).
Lynx health surveillance programme in
Switzerland
Surveillance of lynx health in Switzerland
has been carried out for several decades, im-
plying the close collaboration of veterinarians,
biologists, wildlife managers and museums.
The programme currently in place includes (1)
the pathological examination of all lynx found
dead (whether diseased, poached or traffic-
killed). Carcasses may be found by chance
or recovered thanks to radio-tracking; and (2)
the clinical examination of live lynx (orphans
and older animals captured for management,
conservation or research purposes).
The costs of post-mortem investigations have
been covered by the long-term mandate of
the Swiss Federal Office of the Environment
(FOEN) to the Centre for Fish and Wildlife
Health (FIWI) at the University of Bern for ge-
neral surveillance of wildlife health in Switzer-
land (Ryser-Degiorgis and Segner 2015). The
FOEN has also supported the lynx population
monitoring carried out by the Foundation KORA
(Carnivore Ecology and Wildlife Management)
and attributed mandates to both the FIWI and
KORA for the translocation programmes. Re-
search grants have additionally contributed to
capture costs and genetical analyses, and the
laboratory analyses have been supported by
the Clinical Laboratory of the University of Zu-
rich. An additional contribution has consisted
of non-remunerated personal investment by
multiple collaborators.
Morphological data, pictures of the coat
patterns and samples such as blood are
collected from both dead and live animals.
Faeces from live animals are collected from
the ground, either in the field (on tracks or
around a prey of radio-marked animals) or
during quarantine. Samples are subsequently
analysed and/or archived. Tentative rehabili-
tation of lynx orphans has been carried out
for decades, with disappointing results. The
main limitations have been the political situa-
tion hindering releases into the wild, the lack
of appropriate enclosures, captivity stress
resulting in severe teeth damages, and post-
release issues such as traffic accidents or
predation on domestic animals. Independent
diseased lynx were either treated in the field
and released on site (two cases affected by
sarcoptic mange) or euthanised in quarantine
because of severe debilitation (two cases with
suspected Feline Immunodeficiency Virus (FIV)
infection; Ryser-Degiorgis et al. 2017).
Dead lynx
Post-mortem examinations on Eurasian lynx
found dead, culled or euthanised in Switzer-
land have been carried out since the 1970s
(earliest reports in the FIWI archives) and
the necropsy findings compiled from 1987
Ryser-Degiorgis et al.

The Eurasian lynx in Continental Europe
65
(Schmidt-Posthaus et al. 2002). An extended
necropsy protocol including sample collection
for systematic histological analyses (collec-
tion of baseline data) and for archive purpos-
es was introduced in 2002. The 2004 update
of the official management plan (Swiss lynx
concept, originally implemented in 2000),
required the submission of all dead lynx to a
single institution (FIWI). Since then, the FIWI
has been officially responsible for lynx vete-
rinary examinations and for hosting a sample
archive.
Necropsy and sampling protocols have been
improved over years. The current protocol in-
cludes the following steps (Fig. 1): lynx are
photographed on both sides to record the
individual coat pattern to identify individual
animals for comparison with photo-trapping
data (Thüler 2002, Pesenti & Zimmermann
2013), sex and body condition are deter-
mined, the body weight is recorded, and
standard morphological measurements are
taken (Marti & Ryser-Degiorgis 2018b). Age
is estimated mainly based on dentition, tooth
wear and body size (Fig. 2; Marti & Ryser-
Degiorgis 2018a, 2018b) but also consider-
ing maturity of genital organs and season.
All animals are systematically radiographed
to search for foreign bodies such as ammu-
nition fragments and for skeletal anomalies.
After complete skinning according to muse-
um instructions for subsequent taxidermic
preparation, a thorough gross necropsy is
performed without damaging the skeleton.
A careful macroscopic inspection of the tho-
racic and abdominal cavities as well as of
all internal organs is carried out; pictures of
any abnormality are taken. Weight and other
morphological data of selected organs are
collected, and multiple organ samples fixed
in 4% buffered formalin for histological ex-
amination. Additional native samples (blood,
selected organs) are stored frozen at -20°C
for genetic analysis and at both -20°C and
-80°C for archive purposes. The brain is only
collected if required to achieve a diagnosis,
after consultation and agreement of the local
hunting authorities who submitted the case
(otherwise, skeletons are left intact for taxi-
dermy). Samples of the diaphragm, tongue
and/or masseter muscle, as well as faecal
samples from the rectum, are immediately
submitted to parasitological examination,
namely for the search for Trichinella sp.
Fig. 1. Necropsy protocol for Eurasian lynx
established at the Centre for Fish and Wild-
life Health, University of Bern, Switzerland.
Fig. 2. Decision tree to determine the age of Eurasian lynx (developed for Lynx lynx carpathicus in Switzerland). 1) Marti and Ryser-
Degiorgis 2018a (age estimation based on tooth eruption and tooth wear); 2) MCT = morphology classification tree described in Marti
and Ryser-Degiorgis 2018b (age estimation based on morphological measurements). These two methods have the advantages that they
are noninvasive, costless, deliver immediate results, and can be applied both intra-vitam and postmortem, in any working place. Green
boxes are necessary steps, light grey boxes correspond either to possible confirmatory steps or to a more accurate but invasive ageing
procedure.
health surveillance of Eurasian lynx

CATnews Special Issue 14 Autumn 2021
66
and by necessity (according to clinical signs
or translocation protocols) other clinical
samples (e.g., oropharyngeal, conjunctival or
rectal/faecal swabs) have been sent to the
Clinical Laboratory of the University of Zurich
for immediate analysis (haematology, blood
chemistry, serology, and molecular methods
for pathogen detection).
Lynx protocols for translocation
The first translocation project of Eurasian
lynx from Switzerland (2000–2008) aimed
at reintroducing animals in an area with-
in country borders (Ryser-Degiorgis et al.
2002a, Zimmermann et al. 2011). Subse-
quently, a few lynx were translocated to
Austria for population reinforcement (2011,
2013 and 2017: www.kalkalpen.at/de/Luch-
se_in_den_OOe_Kalkalpen) and Italy (2014:
Molinari et al. 2021), followed by a larger
reintroduction project to southern Germany
(2016–2020: Idelberger et al. 2021). Crossing
national borders implied the fulfilling of ad-
ditional requirements by international regu-
lations (Convention on International Trade in
Endangered Species of Wild Fauna and Flora,
CITES) and the veterinary authorities of the
destination countries. Over the years, health
protocols have evolved based on the acquired
experience and on the health and genetic
data collected.
Disease susceptibility of Eurasian lynx
Firstly, the available published and grey liter-
ature was reviewed, completed by personal
communications from ongoing studies or un-
published data, to provide an overview of the
knowledge on pathogens potentially affect-
ing or carried by lynx (Ryser-Degiorgis 2001,
2009b, Ryser-Degiorgis et al. 2002a).
The main disease of concern was sarcoptic
mange, which emerged in lynx in the Swiss
Alps in the late 1990s (Ryser-Degiorgis et al.
2002b, Schmidt-Posthaus et al. 2002, Mun-
son et al. 2010). This disease is typically ob-
served in lynx in geographical areas where
mange affects the local fox population
(Ryser-Degiorgis 2009b, Munson et al. 2010)
but at the time there was no mange epide-
mic in red foxes Vulpes vulpes in the release
area in north-eastern Switzerland (Pisano et
al. 2019). No specific bacteria was of parti-
cular concern (Ryser-Degiorgis 2001, 2009b)
but feline viruses (Table 1) were considered
a potential threat, considering their signifi-
cance in both domestic and wild felids (Lutz
2005; Leutenegger et al. 1999, Meli et al.
2009). The emphasis on mange and viruses
Fig. 3. Capture protocol for Eurasian lynx
in Switzerland with focus on veterinary
procedures. Details on samples, blood pro-
file and molecular diagnostics are given in
Table 1.
in the health screening of wild felids to be
translocated is also recommended by inter-
national organisations (International Union
for the Conservation of Nature, IUCN; World
Organization for Animal Health, OIE; and Eu-
ropean Association of Zoo and Wildlife Vete-
rinarians, EAZWV; Woodford 2000).
Disease risk in the destination environment
Secondly, information was gathered on po-
tential health risks associated with the des-
tination environment. This was most difficult
to access, as documentation (scientific litera-
ture, unpublished project reports) was poor or
non-existent. Consequently, the risk evaluati-
on in foreign countries largely relied on the
official epizootic disease status of the con-
cerned country and personal communications
from project partners. Nevertheless, for the
first project within Switzerland (2000–2008),
data on prey species from the general wildlife
health surveillance programme were taken
into account, and for the last project (Ger-
many, 2016–2020), the release area being
in geographical continuity with the source
population, it was assumed that the risk of
pathogen exposure would be comparable to
the situation in the capture area.
Criteria for translocation
The selection of individuals aims at: (1) pre-
venting the introduction of lynx either clini-
cally diseased or carrying pathogens repre-
senting a potential threat to other lynx, other
animals (wild or domestic) and humans at the
release site [Figs 4 and 5 (1)]; (2) increasing
the chance of survival of the individuals being
translocated [Fig. 5 (2a, 2b)]; (3) increasing
the chances of reproduction of the released
lynx after translocation; and (4) optimizing the
genetic pool of lynx moved for reintroduction
or reinforcement. These four aspects refer
to health both on an individual (1, 2, 3) and
on a population level (1, 3, 4). Further impor-
tant health considerations on an individual
level include acting with respect of animal
welfare, i.e., selecting appropriate methods
for safe and effective capture/anaesthesia,
stress management and maximal possible
reduction of the risk of injuries.
Criteria for selection revised in 2015 include
the absence/presence of disease signs or
other abnormal observations at clinical ex-
amination, the estimated age (based on the
methods described for dead lynx, see above),
the genetic profile of the animal, and the re-
sults of diagnostic analyses (haematology,
blood chemistry, coprology, and pathogen
(Frey et al. 2009) and for gastrointestinal
helminths and protozoa, respectively. If ne-
cessary, bacteriological, virological or toxi-
cological analyses are initiated to determine
the cause of death.
Live lynx
A procedure similar as that applied to dead
lynx is used for live lynx, starting with the col-
lection of morphological data including body
weight and photographs of the coat pattern
(Fig. 3). Blood has been collected for genetic
analyses since 1993. Since 1997, additional
blood samples have been taken for health in-
vestigations and archiving. Since 2000, a thor-
ough clinical analysis and close anaesthesia
monitoring has been performed on every lynx
manipulated alive (Supporting Online Mate-
rial Figure SOM F1). The corresponding data
have been recorded on paper and the main
information transferred into a digital data-
base. Since 2013, heart sounds have been re-
corded by means of an electronic stethoscope
with record function (3M™Littmann® 3200;
https://www.littmann.com/3M/en_US/
littmann-stethoscopes/), and since 2018
echocardiographies have additionally been
performed, using a portable ultrasound de-
vice (Logiq_e BT12 with transducer 3S-RS
(1,5–4,0 MHz), scil animal care company
GmbH, Germany; SOM F2). Blood samples
Ryser-Degiorgis et al.

The Eurasian lynx in Continental Europe
67
screening as presented in Table 1). The selec-
tion of animals is a process that takes place
in two steps (Fig. 6). A first selection occurs
in the field after examination at the capture
site. Animals considered suitable for the
translocation programme are moved to quar-
antine facilities.
During quarantine, lynx are observed by
video-surveillance while their samples are
tested in the laboratory (blood and genetic
profiles, selected infectious agents and en-
doparasites). Depending on the results, the
lynx will either qualify for immediate trans-
location, or may undergo additional testing
and a prolonged observation period, and/or
receive a specific treatment. In some cases,
repatriation to the original capture site or
even euthanasia may have to be considered
(Fig. 6). During the first translocation project
(2000–2008), quarantine duration used to be
2–3 weeks. Others recommend a minimum
of 30 days for wild felids (Woodford 2000).
However, experience showed that quaranti-
ne duration shall be reduced to a minimum
because of the considerable stress expe-
rienced by lynx caught in the wild and the
resulting self-inflicted injuries when they are
kept in captivity. Besides improvement of the
enclosures (size, structure, materials, sliding
doors between adjacent enclosures, video-
surveillance), nowadays the quarantine lasts
only until all laboratory results are available
and the release logistics (border paperwork,
transport to release site) is set up; all this
takes about a week.
Field procedures
Lynx are captured with foot snares, box traps
or a remote-controlled injection system as
previously described (Breitenmoser et al.
2014, Ryser et al. 2005, Vogt et al. 2016).
Until 2019, subadult and adult lynx were
anaesthetised with an intramuscular injec-
tion of medetomidine hydrochloride (Domi-
tor®, Orion Corporation, Espoo, Finland) in
the rear muscles of a hindleg, followed by
ketamine hydrochloride (Ketasol®-100, Dr. E.
Gräub AG, Bern, Switzerland) 15–20 minutes
later. Since the weight of the animal is not
known before anaesthesia, lynx were admini-
stered a standard dose of 2.8 mg medetomi-
dine and 80 mg ketamine (i.e., approx. 0.13–
0.17 mg/kg medetomidine and 3.6–5.0 mg/kg
ketamine depending on the weight; Marti &
Ryser-Degiorgis 2018a). This is normally suf-
ficient for a safe anaesthesia until the end of
the manipulations. If necessary 0.1–0.2 mg
medetomidine and/or 10–20 mg ketamine
was subsequently injected in the shoulder
musculatur. Atipamezole hydrochloride (Anti-
sedan®, Orion Corporation, Espoo, Finland) at
a dose of five times the medetomidine dosage
(in mg) was used as an antagonist for mede-
tomidine and was injected at least 1 hour af-
ter the last ketamine injection. The effect of
ketamine can last up to approximately 1 hour
and cannot be antagonised. If medetomidine
is antagonised too early, there is a risk of
rough recovery due to the residual effects
of ketamine (Kreeger & Arnemo 2007). Drug
injection in the shoulder results in faster ab-
sorption (Kreeger & Arnemo 2007), which can
be useful in emergency situations. Besides
emergencies, our experience has shown
that shoulder injections are efficient for drug
supplementation during manipulations (see
above). However, for recovery under normal
conditions, antagonist injection in the hind
leg musculature is preferable because it re-
sults in a smoother recovery than if the drug
is administered in the shoulder muscles. This
anaesthesia protocol is well established and
no adverse effects have been recorded, nei-
ther in previous studies (Vogt et al. 2016) nor
in the past few years. However, since 2020,
a single intramuscular injection of 2.2 mg
medetomidine mixed with 80 mg ketamine
Table 1. Testing scheme for Eurasian lynx to be translocated from Switzerland. Since the purpose is, on the one hand, to assess
the health status of each individual, and on the other hand, to prevent the “export” of infectious agents potentially relevant to the
(new) population at the release site, investigations target mainly direct pathogen detection rather than antibodies, because antibodies
indicate past or present exposure of the individual to the microorganism(s) but do not deliver information on its current infection status.
Parameter Target Sample Details/methods
Blood profile Haematology EDTA whole blood + fresh thin
blood smears
Complete blood cell count and white
blood cell differential
Blood chemistry Serum Chemistry profile parameters*
FeLV1Free FeLV p27 antigen Serum ELISA2
FeLV whole virus (FL74) and/or FeLV
p15E antibodies
Serum ELISA
Proviral DNA EDTA whole blood Real-time TaqMan qPCR3
FIV4FIV antibodies Serum FIV-Westernblot
Feline Herpesvirus Viral DNA Conjunctival swab Real-time TaqMan qPCR
Feline Calicivirus Viral RNA Oropharyngeal swab Real-time TaqMan RT5-qPCR
Canine Distemper Virus Viral RNA Oropharyngeal swab Real-time TaqMan RT-qPCR
Feline Parvovirus Viral DNA Rectal or faecal swab Real-time TaqMan qPCR
Feline Coronavirus Viral RNA Rectal or faecal swab Real-time TaqMan RT-qPCR
1 FeLV: Feline Leukaemia Virus. 2ELISA Enzyme-linked immunosorbent assay. 3 qPCR: quantitative polymerase chain reaction. 4 FIV: Feline Immunodeficiency Virus. 5 RT: reverse
trancriptase. * Parameters: total bilirubin, glucose, urea, creatinine, total protein, albumin, globulin, cholesterol, triglycerides, alkaline phosphatase, alanine aminotransferase,
aspartate aminotransferase, lipase, creatine kinase, calcium, phosphorus, sodium, potassium, chloride
health surveillance of Eurasian lynx

CATnews Special Issue 14 Autumn 2021
68
has been used per lynx to reduce the induc-
tion time, followed by the same procedure
for reversal as before. This new protocol has
been used for only a few lynx so far but ap-
pears to be promising.
During anaesthesia (SOM F2), respiratory
rate, heart rate, pulse rate, mucous mem-
branes (capillary refill time and colour), rectal
temperature and reflexes are continuously
monitored by a person previously designat-
ed for this task. Blood oxygen saturation is
measured with a portable pulse oximeter
(Pulse Oximeter, CONTEC Medical Systems
Co., LTD, Qinhuangdao, China). All values and
observations are recorded in an anaesthesia
datasheet. The most critical point encoun-
tered during field anaesthesia of lynx has
been related to the body temperature, name-
ly hypothermia during cold days, especially in
rainy or snowy weather and hyperthermia at
mild environmental temperatures. In these
situations, prevention is crucial as it is very
challenging to reverse the development in
one direction or the other. Details on mani-
pulation and emergency procedures can be
found elsewhere (Breitenmoser et al. 2014,
Kreeger & Arnemo 2007).
Captured animals are examined clinically,
with particular attention to their general ap-
pearance, body condition, size and weight,
tooth wear and genitals. Animals in a normal
body condition (considering that adult males
may be thinner during the mating season
than at other times of the year), aged more
than one year but no more than 13 years
old, and without significant clinical abnor-
malities (such as a recent fracture, infected
wounds, mange lesions, a heart murmur or
a potentially inherited malformation such as
cryptorchidism), are considered as adequate
for a transfer to quarantine facilities (Fig. 6).
By contrast, obviously old lynx (based on tooth
wear, e.g., severely worn or discoloured teeth;
Marti & Ryser-Degiorgis 2018b), lynx with a
heart murmur or a nonlethal malformation
of potential genetic origin, are directly re-
leased on site; those with a heart murmur
may be radio-collared to follow the evolution
of their condition and to eventually recover
their carcasses for pathological examination.
Lynx younger than one year or presenting a
disease or trauma with good chances of heal-
ing (e.g., mange after appropriate treatment)
may be released on site with a GPS collar to
be re-captured at a convenient time. In some
cases, a transfer to the quarantine station for
more intensive care may be considered. How-
ever, animal welfare aspects must be taken
into account (e.g., stress induced by transport
and captivity may have a negative impact on
health), as well as the risk that an animal
suffering from an infection may represent to
other lynx already present in the quarantine
facility (although this risk largely depends
on the building structure and quarantine ma-
nagement).
All lynx selected for translocation receive an
antiparasitic treatment (single subcutaneous
injection of praxiquantel: Caniquantel pro
Inj., Dr. E. Gräub AG, Berne, Switzerland, at
a dosage of 5.68 mg/kg; and of doramectin:
Dectomax®, Elanco Tiergesundheit AG, Basel,
Switzerland, at a dosage of 1 mg/kg; this do-
ramectin dosage has led to a full recovery of
lynx heavily affected by mange; Ryser-Degior-
gis 2013) to reduce the risk of translocating
apparently healthy lynx infested with mange
mites (early disease stage or healthy car-
riage; Munson et al. 2010) and in the hope
to decrease their helminth burden (Woodford
2000), which may have a greater health im-
pact under stressful conditions. Any neces-
sary wound treatment is made at this time
point. Other medication (including antibiotics)
is not administrated unless it appears appro-
priate based on the clinical findings. Vaccina-
tion is only foreseen if authorities of the reci-
pient country require it. The rationale behind
this decision is that (1) vaccination provides
protection only for a limited amount of time;
since both repeated vaccination boost(s) and
systematic vaccination of offspring are un-
practicable in a free-living population, ani-
mals unable to cope with the infection risks in
Fig. 4. Health risks associated with lynx translocations at population level. Moved
wild animals can bring microorganisms or deleterious genes to the destination envi-
ronment, which may cause disease in individuals of the same species, in other wild-
life, in domestic animals or in humans.
Fig. 5. Health risks associated with lynx translocations include the potential introduc-
tion of a pathogen (infectious agent with the potential to cause disease) or deleterious
genes into the destination population (to be reinforced or reintroduced) by the animals
being translocated (1); and the potential transmission (by other animals or the envi-
ronment) of a pathogen new to the lynx being translocated as well as the exposure to
toxic compounds from the environment or other non-infectious causes of disease or
mortality during (2a) or after (2b) the translocation process.
Ryser-Degiorgis et al.

The Eurasian lynx in Continental Europe
69
their new environment would not survive on
the long term; and (2) vaccination with inac-
tivated vaccines offer only limited protection,
while the use of live vaccines in wildlife spe-
cies may cause disease or even death (Con-
nolly et al. 2015).
All captured lynx are marked with a subcu-
taneous transponder (microchip; DATAMARS,
https://datamars.com/) implantation in the
midway region on the left side of the neck
(according to the standards of the Global Vete-
rinary Community for domestic cats and other
companion animals in continental Europe;
https://www.wsava.org/Global-Guidelines/
Microchip-Identification-Guidelines) and
blood-sampled. Pharyngeal, conjunctival and
rectal dry swabs are collected. In recent years
a point-of-care test (i.e., a fast field test) for
Feline Immunodeficiency Virus (FIV) antibody
and Feline Leukaemia Virus (FeLV) antigen
detection validated for domestic cats (SNAP
FIV/FeLV Combo Test, IDEXX, Switzerland) has
been used in the field, as the selection criteria
foresee to exclude individuals with a positive
result. However, experiences with testing for
FIV in 2016 and 2017 have shown that this fast
field test may deliver false negative results
when applied on lynx samples and that testing
in the laboratory is required to obtain reliable
data on FIV infection. As experiences in the
Iberian lynx suggest that the test can detect
progressive FeLV infections that might end fa-
tally, lynx fulfilling criteria for translocation are
brought to quarantine without SNAP testing
and tested in the laboratory. Lynx not fulfilling
translocation criteria and planned to be re-
leased on site should be tested with the SNAP
test and taken to captivity in case of a positive
result. If a progressive infection is confirmed
by laboratory testing, they should be extracted
from the population (Meli et al. 2010a).
Lynx transport has proven to be a more
challenging step than originally thought. If
anaesthetised and slowly recovering during
transport, constant monitoring of vital pa-
rameters is required until recovery, and lynx
tend to develop hypothermia even in a heat-
ed vehicle. If transported after anaesthesia
reversal, lynx might be stressed and thus at
risk of injuries (splitted claws, broken teeth,
skin abrasion on the forehead) and cardio-
respiratory distress (hyperthermia, hyperven-
tilation). However, anaesthesia reversal is
preferred, as risks of stress and injuries also
concern lynx recovering from anaesthesia du-
ring transport and in case of transboundary
translocations transport may be very long.
There are marked and unpredictable interin-
dividual differences in behaviour and stress-
susceptibility but since interventions cannot
be performed on a conscious lynx, once more,
prevention is key. It is important for humans
accompanying the animal during transport to
stay quiet (no loud voices or sudden noises)
and to cool down the interior of the vehicle.
Furthermore, over the years, the transport
boxes have been improved to be able to in-
terchange doors without opening the boxes,
and thus have the possibility to either keep
the animal in the dark (full door) or to improve
ventilation (metal bar door) by interchanging
door types (SOM F3). Additionally, active ven-
tilation into the box with an external device
has had a calming effect on stressed lynx. Ex-
tensive general guidelines on the transport of
live animals can be found elsewhere (e.g., the
"IATA Live Animals Regulations" (LAR), which
is the global standard and the essential guide
to transporting animals by air in a safe, hu-
mane and in a cost-effective manner (https://
www.labeline.com/product/iata-live-animal-
regulations-lar-46th-edition-2020); and the
CITES guidelines for the non-air transport of
live wild animals and plants (https://cites.
org/sites/default/files/eng/resources/trans-
port/transport_guidelines_2013-english.pdf).
Pre-release procedures
Blood samples taken at capture are analysed
in the laboratory. Haematology and blood
chemistry values are compared with refe-
rence values obtained from clinically healthy
Fig. 6. Selection criteria currently applied for translocation of lynx from Switzerland. FIV:
Feline Immunodeficiency Virus; FeLV: Feline Leukaemia Virus; FPV: Feline Parvovirus;
CDV: Canine Distemper Virus.
health surveillance of Eurasian lynx

CATnews Special Issue 14 Autumn 2021
70
free-ranging Eurasian lynx from Switzerland.
The first faeces found in the enclosure is
collected and analysed for lung and gastro-
intestinal parasites by coprology. Blood and
swab samples are tested by molecular meth-
ods and/or serology for selected infectious
agents (Table 1).
Based on the data collected in Switzerland
since the first lynx reintroductions and on
studies published on wild felids elsewhere in
Europe, we classified microorganisms poten-
tially occurring in lynx into three risk levels:
(1) High risk: Only infections with FeLV and FIV
were considered as a criterion for exclusion,
as these viruses had not previously been de-
tected in free-ranging or captive populations
of Eurasian lynx and were considered having
the potential to seriously harm infected ani-
mals (Meli et al. 2009, Geret et al. 2011, Tro-
yer et al. 2011).
(2) Mild to moderate risk: In the case of other
agents such as Canine Distemper Virus (CDV)
or Feline Parvovirus (FPV), which may cause
disease in lynx (Stahl and Vandel 2009, Wa-
sieri et al. 2009, Meli et al. 2010, Origgi et
al. 2012) but are also known to occur (FPV
PCR-positive, CDV-seropositive) without
associated morbidity and mortality in appa-
rently healthy lynx populations, or such as
Feline Calicivirus, Feline Herpesvirus and
Feline Coronavirus, for which there is serolo-
gic evidence of exposure but no known mor-
bidity (Meli et al. 2009; Ryser-Degiorgis and
Meli, unpubl.), the clinical status and blood
parameters of the animals are more relevant
criteria to evaluate their individual health sta-
tus than the detection of the pathogen. On a
population/ecosystem level, the relevance of
pathogen detection depends on the harm it
may cause at the release site.
(3) Minimal risk: Infectious agents such as
Cytauxzoon spp., feline haemotropic mycoplas-
mas and intestinal endoparasites are wide-
spread in clinically healthy lynx (Valdmann et
al. 2004, Willi et al. 2007, Millán et al. 2007,
Meli et al. 2009, Ryser-Degiorgis et al. 2010a,
Deksne et al. 2013) and not expected to be a
threat to lynx or to represent a serious risk
for other felid species in the framework of
Eurasian lynx translocations. Their detection
should serve as a documentation for the long-
term health monitoring of the source and of
the re-introduced populations but is currently
not considered a criterion for selection of lynx
in the framework of translocations. There-
fore, samples for additional tests of scientific
value but not relevant to immediate translo-
cation are stored for potential later analysis.
Animals with blood values significantly
diverging from reference data or with in-
fections of unclear clinical significance are
observed more closely, possibly longer, and
submitted to additional testing as appro-
priate. The genetic profile of all animals is
determined during the quarantine period. In
case of close relatedness (brother and sister;
mother/father and offspring) with other lynx
already translocated or simultaneously kept
in quarantine for translocation, the animal
is excluded from the programme and repatri-
ated to the capture site.
Before transfer to the release site, lynx are
anaesthetised to be fitted with a GPS collar
and undergo another clinical check before
transportation. They are blood-sampled for
archive purposes, i.e., no test is performed at
this point without a specific indication. If a
reason for exclusion (see above) not noticed
earlier is detected, experts in charge consider
three options: (1) repatriation to the original
capture site, (2) prolongation of the quaranti-
ne (with treatment as appropriate and subse-
quent re-assessment), or (3) euthanasia. Ra-
diographs or additional laboratory tests are
performed only in case of specific indication.
No treatment is administered at the time of
release unless indicated by clinical findings.
If the suitability of an individual is questio-
nable, the decision whether to translocate it
or not is taken together with the project part-
ners in the recipient country.
A summary of the identified health risks and
the corresponding management measures is
presented in Table 2.
Translocation challenges encountered
in Switzerland
Sarcoptic mange was first detected in lynx
in Switzerland in 1999 (Ryser-Degiorgis et
al. 2002b, Schmidt-Posthaus et al. 2002). At
the time, there was no indication of another
health issue relevant to translocations in the
Swiss lynx population (Ryser-Degiorgis et
al. 2002a). More cases of mange were diag-
nosed since then, including captured lynx that
were successfully treated (Ryser-Degiorgis
2013). This occurred simultaneously with the
Swiss-wide spread of sarcoptic mange in the
red fox (Pisano et al. 2019). Similarly, in the
framework of the large canine distemper out-
break that has affected Swiss wildlife since
2009, an infected Eurasian lynx was observ-
ed with clinical signs (Origgi et al. 2012).
Cytauxzoon spp. was found for the first time
in a severely debilitated lynx in 2006, but the
hypothesis of its causal role was discarded
by the pathological examination that fol-
lowed euthanasia. As the significance of this
pathogen was still unclear, raising questions
regarding the suitability of positive animals
for translocation programmes, a retrospec-
tive study on archived samples and syste-
matic testing of lynx to be translocated were
initiated, which showed that this haemopar-
asite is widespread in lynx from Switzerland
(Ryser-Degiorgis et al. 2010b). Feline Parvo-
virus infection (viraemia and faecal excretion)
without associated disease signs was first
found in an orphaned lynx in 2012, and again
in an adult lynx to be translocated to Austria
(viraemia only) in 2013 (Ryser-Degiorgis &
Meli, unpubl.). In 2017 a lynx was diagnosed
with ocular chlamydiosis (Marti et al. 2019),
and two animals with unspecific disease
signs were suspected to be infected with
FIV (Ryser-Degiorgis et al. 2017). In 2019, an
apparently healthy male was confirmed to
be latently infected with FeLV (detection of
proviral DNA and anti-whole virus and p15E
antibodies, i.e., regressive FeLV infection) and
was repatriated to the capture site fitted with
a radio-collar; no disease sign development
has subsequently been observed (Marti et
al. unpubl.). Concerning non-infectious dis-
eases, sporadic congenital malformations
have been observed over the past decades
(Morend 2016, Ryser-Degiorgis et al. 2004).
Genetic analyses have revealed a loss of
variability and increasing inbreeding main-
ly in the Alps (Breitenmoser-Würsten &
Obexer-Ruff 2003). Heart murmurs have in-
creasingly been detected in Alpine lynx since
2001, after a lynx with such a murmur was
translocated and died of cardiac failure due
to a cardiomyopathy two years after release
(Ryser-Degiorgis et al. 2020). A few more
fatal cardiomyopathies have been diag-
nosed since then, and meanwhile there are
indications that the observed heart anoma-
lies (murmurs, histological cardiac lesions),
whether associated with disease signs or
not, may be related to inbreeding (Ryser-De-
giorgis et al. 2018). As new knowledge has
been gathered on this issue, it has progres-
sively led to the exclusion of individual lynx
with heart murmurs from translocation pro-
grammes, and since 2015 even of the whole
Alpine lynx population. Other aspects of the
health screening protocol (selected agents,
collected samples and applied laboratory
tests) have been improved and selection
criteria for individual lynx have been refined
(Table 2, Fig. 6). The management of health-
relevant findings detected in individual lynx
Ryser-Degiorgis et al.

The Eurasian lynx in Continental Europe
71
Table 2. Health risk management in the framework of translocation of free-ranging Eurasian lynx from Switzerland.
Health issue Risk management
POTENTIALLY INHERITED
Heart murmurs of potential genetic origin incl. a few fatal cases
(Alpine population)
Exclusion of all Alpine lynx as well as individuals from other populations presenting
with a heart murmur
Sporadic malformations of various body parts Documentation of visible anomalies at clinical examination; exclusion if suspected
inheritance (e.g., cryptorchidism)
INFECTIOUS
High risk: FeLV1, FIV2 (no infection known in the source
population, potential threat to both the source and destination)
Systematic testing; if confirmed positive for FIV or progressive FeLV infection:
observation, with additional testing if deemed appropriate, followed by repatriation or
euthanasia
Moderate risk: Canine Distemper Virus (moderate disease risk),
Feline Parvovirus (low disease risk but cannot be excluded: see
Stahl & Vandel 2009), Feline Herpesvirus, Feline Calicivirus and
Feline Coronavirus
Systematic testing, decision based on clinical status and re-testing (aim: to minimize
the risk of excretion)
Minimal risk: Cytauxzoon spp., feline haemotropic
mycoplasmas, among other microorganisms (no known cases of
clinical disease)
No systematic testing (scientific documentation only and/or surveillance data
collection)
Sarcoptic mange
(also notoedric, otodectic)
Systematic treatment against mites (aim: to eliminate mites)
Endoparasites (gastrointestinal helminths) Systematic treatment and testing (aim: to minimize the risk of increase of endoparasite
burden and associated apparition of clinical signs potentially resulting from increased
stress)
OTHERS
Any other viral or bacterial infection; ecto- or endoparasitic
infestation; trauma; or detection of unspecific disease signs
Treatment if available and appropriate (on medical, financial, logistical and animal
welfare points of view), observation of clinical status, additional testing if deemed
useful; depending on disease course: translocation, repatriation or euthanasia
1 FeLV: Feline Leukaemia Virus. 2 FIV: Feline Immunodeficiency Virus
during translocation projects since 2013 is
summarized in Table 3.
Detailed records of clinical findings and
anaesthesia procedures have contributed
to the improvement of capture methods and
prevention measures aimed at decreasing
capture-related risks. In particular, aware-
ness was raised regarding the elevated risk
of injuries when using box traps made of
metallic grid, of hypothermia in winter and
of hyperthermia during transport as well as
when using foot snares in the spring. Alrea-
dy after the first year of the first project (i.e.,
at the end of 2001), improvements were
made to box traps to reduce the risk of inju-
ries at capture and to housing conditions to
reduce the risk of injuries and stress during
quarantine, followed later on by modifica-
tions of transport boxes to reduce the risk of
injuries, stress and associated hyperthermia
and to provide possibilities to better venti-
late and observe the animals during trans-
port. Importantly, as stated above, the dura-
tion of the quarantine has been drastically
shortened, being now limited to the time
required for relevant laboratory results to be
available, unless there are indications for a
prolongation.
Of the few females diagnosed as pregnant
at the end of the quarantine, some gave birth
after translocations, others did not, suggest-
ing that the stress caused by transport and
release in a new environment, alone or in
addition to that induced by the initial cap-
ture, first transport and quarantine period
(i.e., additive stressful situations), might
cause abortion. However, to our knowledge,
to date there is no scientific evidence sup-
porting this hypothesis (Vié et al. 1998,
Kreeger 2012, Nagel et al. 2019), hinting at
a minimal risk of abortion due to translocat-
ing procedures. Since the period of the year
associated with the highest lynx capture
success is the mating season (males on
the move for reproduction purposes, snowy
landscapes resulting in a higher likelihood
for prey to be found and a frequent use of
existing paths where box traps are placed),
it is inevitable to capture and move poten-
tially pregnant females.
Conclusions
Health risk analysis in the framework of lynx
translocations has proven to be an important
tool to reduce the risk of project failure, con-
sidering that a range of pathogens have been
detected, which required case-specific mana-
gement measures. These experiences have
also underlined the importance of a health
surveillance programme starting prior to a
translocation project and of the usefulness
of a sample archive. Furthermore, the lack
of data on disease risk at the release sites
pointed at the necessity to carry out health
surveillance in both domestic animals and
wildlife to provide data useful to the planning
of species conservation projects.
It is important to remember that it will never
be possible to work with zero risk, and that
one needs to be ready to experience the un-
expected and to show adaptation potential
after careful planning. Although not men-
tioned further here, post-release monitoring
not only of the lynx behaviour, reproduction
and population genetics but also of health
issues (particularly the thorough examination
health surveillance of Eurasian lynx

CATnews Special Issue 14 Autumn 2021
72
Table 3. Health issues encountered during capture and quarantine of Eurasian lynx caught for translocation in Switzerland, 2001–
2020.
Health issue Decision criteria Case management and decision Reference
Heart murmur (in
absence of associated
clinical signs)
- DS1: None; TH2: None
- Previous data: suspected inherited
cardiomyopathy
REPATRIATION (Ryser-Degiorgis et al. 2018)
Parvovirus infection
and excretion (faeces)3
- DS: None; TH: None
- Not all Parvoviruses cause disease
- Previously same situation in orphaned
lynx: remained healthy, excretion
stopped, was released and followed up
Retesting, negative in faeces (no
excretion) and TRANSLOCATION
(Ryser-Degiorgis & Meli,
unpubl.)
Cytauxzoon spp.
infection3
- DS: None; TH: None
- Retrospective analysis: many Swiss
lynx infected, no known fatal cases
in domestic cat in Europe at the time4
(questionable parasite pathogenicity)
- Widespread in healthy bobcats and
Iberian lynx5
TRANSLOCATION (Ryser-Degiorgis et al. 2010a)
Suspected FIV6
infection
- DS: present and potentially associated
with FIV infection
- TH: None available
- Deterioration of health status in
quarantine
- Retrospective analysis with reliable
test (gold standard): Absence of
positive lynx in source population
confirmed
EUTHANASIA (Ryser-Degiorgis et al. 2017)
Chlamydiosis - DS: Yes, typical for infection; TH: Yes,
available and feasible
- No other known disease case in source
population, infection status population
unknown (neither previous data nor
appropriate samples available)
TREATMENT, observation until total
recovery and TRANSLOCATION
(retesting at release and post-
release observation by photo-
trapping)
(Marti et al., 2019)
FeLV7 infection - DS: None; TH: None
- Previous data: No infection in source
population
- Regressive infection, high antibody
titre, no virus shedding
REPATRIATION
and follow up (GPS collar, photo-
trapping)
(Marti et al., unpubl.)
1DS: Disease signs; 2TH Available therapy; 3These experiences contributed to the classification of the corresponding infectious agents in the currently used
risk category (see Table 2). 4Since then, Cytauxzoon spp. has been shown to occur in both wild and domestic felids in Europe, with varying pathogenicity (from
asymptomatic to fatal infections) and sometimes uncertain causal relationship between the infection and observed clinical signs (Nentwig et al. 2018, Panait
et al. 2021). 5Since then, Cytauxzoon spp. has also been detected in Eurasian lynx in Romania (Gallusová et al. 2016) and reported in European wildcats by
multiple authors (Panait et al. 2021). 6FIV: Feline Immunodeficiency Virus; 7FeLV: Feline Leukaemia Virus.
of dead lynx) is a crucial point to evaluate the
success of the project on a longer term and
to determine the need for additional manage-
ment measures.
Twenty years ago, when veterinary supervi-
sion was first implemented for lynx trans-
location projects in Switzerland, hardly any
health issue was a limiting factor and infec-
tions seemed to be of minor importance, but
over the past 10 years a range of microor-
ganisms with pathogenic potential have
been newly detected. The change from sero-
logical investigations to pathogen detection
may have favoured this situation, however,
pathogen detection partly followed the de-
tection of associated clinical signs (Origgi
et al. 2012, Ryser-Degiorgis et al. 2017,
Marti et al. 2019). While both antigen and
antibody detection are essential to study
pathogen/ disease dynamics in a popula-
tion, only pathogen detection is relevant
for decision-making in the framework of
translocations (risk of excretion potentially
leading to disease in stressed animals or re-
sulting in contamination/transmission at the
release site). On the same line, it is crucial
to distinguish infection and exposure from
Ryser-Degiorgis et al.

The Eurasian lynx in Continental Europe
73
disease and not to be misled by results of
serosurveys (Munson et al. 2010).
The infections documented in lynx in Switzer-
land were most likely sporadic and related
to the occurrence of the corresponding in-
fectious agents in sympatric hosts such as
foxes [sarcoptic mange (Ryser-Degiorgis et
al. 2002b, Pisano et al. 2019); distemper (Ori-
ggi et al. 2012)] and possibly domestic cats
and/or European wildcats Felis sylvestris [FIV
(Ryser-Degiorgis et al. 2017); FeLV (Leuteneg-
ger et al. 1999, Meli et al. 2009, Geret et al.
2011, Hofmann-Lehmann et al. 2018); Chla-
mydia felis (Marti et al. 2019)]. Current in-
formation on Swiss stray and feral domestic
cats is limited (Berger et al. 2015, Hofmann-
Lehmann et al 2018; Novacco et al., 2019),
but personal communications from clinical
pathologists at the Clinical Laboratory of the
University of Zurich support the occurrence of
FeLV and suggest the presence also of other
viruses such as FIV in feral and stray cats po-
tentially sharing lynx habitat (B. Riond, pers.
comm.). The regular record of heart anoma-
lies possibly associated with a loss of genetic
variability (Ryser-Degiorgis et al. 2018), have
added concerns regarding the health status
of the source populations and underlined the
necessity of considering also non-infectious
diseases in health risk assessments in the
context of translocation projects.
Health surveillance and retrospective studies
require access to a sample size sufficient for
inference at population level (Ryser-Degiorgis
2013). In protected secretive species, the ac-
cess to samples is typically difficult, as ani-
mals found dead and captured individuals re-
present the only possible sources of material.
From a strategic viewpoint, three components
of health surveillance appear to be particular-
ly important: (1) long-term data and sample
collection; (2) interdisciplinary collaboration
and a combination of multiple diagnostic
approaches (e.g., clinical and post-mortem
examinations, laboratory tests, observations
of disease signs by photo-trapping; examina-
tion of both marked animals and those found
by chance; examination of diseased and of
apparently healthy animals such as traffic
kills, which can provide baseline data); (3)
harmonization of data collection over time
and among study areas to allow for compa-
risons. Last but not least, data need to be
regularly compiled to improve protocols and
procedures as appropriate. Overall, the aim
is to carry out adaptive management based
on scientific data (Fig. 5). For a pan-European
conservation programme of Eurasian lynx,
coordinated efforts are advisable. Among
others, the harmonization of veterinary proto-
cols and genetic investigations is desirable,
as well as the exchange of information on
detected health issues.
Acknowledgements
Many thanks go to all project partners and many
associated collaborators, from the field to the
laboratory, in Switzerland and in neighbouring
countries, for the good collaboration. Special ac-
knowledgements go to all involved collaborators
of the KORA and FIWI, in particular Andreas Ry-
ser, Fridolin Zimmermann and Mirjam Pewsner,
and to the former head Hans Lutz, veterinarians
and technicians of the Clinical Laboratory for their
highly appreciated contributions. The laboratory
work was partly performed using the logistics of
the Center for Clinical Studies at the Vetsuisse Fa-
culty of the University of Zurich. Mandates related
to lynx translocations and lynx health surveillance
in general as well as the corresponding funding
schemes were attributed to KORA and FIWI by the
Swiss Federal Office for the Environment.
References
Berger A., Willi B., Meli M. L., Boretti F. S.,
Hartnack S., Dreyfus A., Lutz H. & Hofmann-
Lehmann R. 2015. Feline calicivirus and other
respiratory pathogens in cats with Feline
calicivirus-related symptoms and in clinically
healthy cats in Switzerland. BMC Veterinary
Research 11, 282.
Bozzuto C., Biebach I., Muff S., Ives A. R. & Kel-
ler L. F. 2019. Inbreeding reduces long-term
growth of Alpine ibex populations. Nature Eco-
logy & Evolution 3, 1359–1364.
Brambilla A., Biebach I., Bassano B., Bogliani G.
& von Hardenberg A. 2015. Direct and indirect
causal effects of heterozygosity on fitness-
related traits in Alpine ibex. Proceedings of the
Royal Society B 282, 20141873.
Breitenmoser U., Ryser A. & Ryser-Degiorgis M.-
P. 2014. Dokumentation Fang, Narkose und
Markierung von Raubtieren. KORA, Muri bei
Bern, und FIWI, University of Bern, Switzer-
land, 33 pp.
Breitenmoser U., Breitenmoser Ch. & Capt S. 1998.
Re-introduction and present status of the lynx
(Lynx lynx) in Switzerland. Hystrix Italian Jour-
nal of Mammalogy 12, 17–27.
Breitenmoser-Würsten Ch. & Obexer-Ruff G. 2003.
Population and conservation genetics of two
re-introduced lynx (Lynx lynx) populations
in Switzerland – a molecular evaluation 30
years after translocation. In Proceedings of
the 2nd Conference on the Status and Conser-
vation of the Alpine Lynx Population (SCALP),
7–9 May 2003. Amden, Switzerland. Environ-
mental Encounters 58, 28–31.
Chapron G., Kaczensky P., Linnell J. D. C., von Arx
M., Huber D., Andrén H., ... & Boitani L. 2014.
Recovery of large carnivores in Europe’s mo-
dern human-dominated landscapes. Science
346, 1517–519.
Connolly M., Thomas P., Woodroffe R. & Raphael
B. L. 2015. Single- versus double-dose rabies
vaccination in captive African wild dogs (Lyca-
on pictus). Journal of Zoo and Wildlife Medi-
cine 46, 691–698.
Daszak P., Cunningham A. A. & Hyatt A. D. 2000.
Emerging infectious diseases of wildlife –
threats to biodiversity and human health. Sci-
ence 287, 443–449.
Fig. 7. Conservation
of lynx populations,
including but not
limited to transloca-
tion procedures, re-
quires adaptive man-
agement based on
scientific data. This
corresponds to a nev-
er ending learning
process translating
into continuous pro-
tocol adaptation.
health surveillance of Eurasian lynx

CATnews Special Issue 14 Autumn 2021
74
Deksne G., Laakkonen J., Näreaho A., Jokelainen
P., Holmala K., Kojola I. & Sukura A. 2013.
Endoparasites of the Eurasian lynx (Lynx lynx)
in Finland. The Journal of Parasitology 99,
229–234.
Dirzo R., Young H. S., Galetti M., Ceballos G., Isaac
N. J. B. & Collen B. 2014. Defaunation in the
Anthropocene. Science 345, 401–406.
Frey C. F., Schuppers M. E., Müller N., Ryser-Degi-
orgis M.-P. & Gottstein B. 2009. Assessment of
the prevalence of Trichinella spp. in red foxes
and Eurasian lynxes from Switzerland. Veteri-
nary Parasitology 159, 295–299.
Gallusová, M., Jirsová D., Mihalca A. D., Gher-
man C. M., D’Amico G., Qablan M. A., Modrý
D. 2016. Cytauxzoon infections in wild felids
from Carpathian-Danubian-Pontic space: further
evidence for a different Cytauxzoon species in
European felids. Journal of Parasitology 102,
377–380.
Geret C. P., Cattori V., Meli M. L., Riond B., Martí-
nez F., López G., Vargas A., Simón M. A., López-
Bao J. V., Hofmann-Lehmann R. & Lutz H. 2011.
Feline leukemia virus outbreak in the critically
endangered Iberian lynx (Lynx pardinus): high-
throughput sequencing of envelope variable
region A and experimental transmission. Ar-
chives of Virology 156, 839–854.
Grossen C., Biebach I, Angelone-Alasaad S., Kel-
ler L. F. & Croll D. 2018. Population genomics
analyses of European ibex species show lower
diversity and higher inbreeding in reintroduced
populations. Evolutionary Applications 11,
123–139.
Hofmann-Lehmann R., Gönczi, Riond B., Meli M.
L., Willi B., Howard J., Schaarschmidt-Kiener
D., Regli W., Gilli U. & Boretti F. 2018. [Feline
leukemia virus infection: importance and cur-
rent situation in Switzerland]. Schweizer Ar-
chiv für Tierheilkunde 160, 95–105.
Idelberger S., Krebühl J., Back M., Ohm J., Prüs-
sing A., Sandrini J. & Huckschlag D. 2021.
Reintroduction of Eurasian lynx in the Palati-
nate Forest, Germany. Cat News Special Issue
14, 38–42.
Kock R. A., Mihok S. R., Wambua J., Mwanzia J.
& Saigawa K. 1999. Effects of translocation
on hematologic parameters of free-ranging
black rhinoceros (Diceros bicornis michaeli) in
Kenya. Journal of Zoo and Wildlife Medicine
30, 389–396.
Kock R. A., Woodford M. H. & Rossiter P. B. 2010.
Disease risks associated with the translocation
of wildlife. Revue Scientifique et Technique de
l’Office International des Epizooties (OIE) 29,
329–350.
Kreeger T. J. & Arnemo J. M. 2012. Animal cap-
ture: putting it all together. In Handbook of
Wildlife Chemical Immobilization 4th edition.
Laramie, Wyoming, United States, published
by the authors.
Leutenegger C. M., Hofmann-Lehmann R., Ri-
ols C., Liberek M., Worel G., Lups P., Fehr D.,
Hartmann M., Weilenmann P. & Lutz H. 1999.
Viral infections in free-living populations of the
European wildcat. Journal of Wildlife Diseases
35, 678–686.
Lutz H. 2005. Virusinfektionen. In Krankheiten
der Katze. Horzinek M. C., Schmidt V. & Lutz
H. (Eds). Enke Verlag, Stuttgart, Germany, pp.
107–155.
Marti I., Pisano S. R. R., Wehrle M., Meli M. L.,
Hofmann-Lehmann R. & Ryser-Degiorgis M.-
P. 2019. Severe conjunctivitis associated with
Chlamydia felis infection in a free-ranging
Eurasian Lynx (Lynx lynx). Journal of Wildlife
Diseases 55, 522–525.
Marti I. & Ryser-Degiorgis M.-P. 2018a. Mor-
phometric characteristics of free-ranging Eu-
rasian lynx Lynx lynx in Switzerland and their
suitability for age estimation. Wildlife Biology
2018, wlb.00432.
Marti I. & Ryser-Degiorgis M.-P. 2018b. A tooth
wear scoring scheme for age estimation of the
Eurasian lynx (Lynx lynx) under field conditions.
European Journal of Wildlife Research 64, 37.
Meli M. L., Cattori V., Martínez F., López G., Vargas
A., Simón M. A., ... & Lutz H. 2009. Feline leu-
kemia virus and other pathogens as important
threats to the survival of the critically endan-
gered Iberian lynx (Lynx pardinus). PLOS ONE
4, e4744.
Meli M. L., Simmler P., Cattori V., Martínez F.,
Vargas A., Palomares F., ... & Lutz H. 2010.
Importance of canine distemper virus (CDV) in-
fection in free-ranging Iberian lynxes (Lynx par-
dinus). Veterinary Microbiology 146, 132–137.
Millán J., Naranjo V., Rodríguez A., de la Lastra J.
M. P., Mangold A. J. & de la Fuente J. 2007.
Prevalence of infection and 18S rRNA gene
sequences of Cytauxzoon species in Iberian
lynx (Lynx pardinus) in Spain. Parasitology 134,
995–1001.
Molinari P., Breitenmoser U., Cerne R., Fuxjäger
C., Weingarth K., Ryser A. & Molinari-Jobin
A. 2021. The contribution of stepping-stone
releases for enhancing lynx distribution. Cat
News Special Issue 14, 46–49.
Morend F. 2016. Radiologic investigations of
pelvic bone structures in reintroduced free-
ranging Eurasian lynx in Switzerland. Master
Thesis, Vetsuisse Faculty, University of Bern.
44 pp.
Munson L., Terio K. A., Ryser-Degiorgis M.-P., Lane
P. E. & Courchamp F. 2010. Wild felid diseases:
conservation implications and management
strategies. In Biology and conservation of wild
felids. MacDonald D. W. and Loveridge A. J.
(Eds) Oxford University Press Inc., New York,
United States, pp. 237–259.
Nagel C., Aurich C.& Aurich J. 2019. Stress effects
on the regulation of parturition in different do-
mestic animal species. Animal Reproduction
Science 207, 153–161.
Nentwig A., Meli M. L., Schrack J., Reichler I.M.,
Riond B., Gloor C., … & Hofmann-Lehmann R.
2018. First report of Cytauxzoon sp. infection
in domestic cats in Switzerland: natural and
transfusion-transmitted infections. Parasites &
Vectors 11, 292.
Novacco M., Kohan N. R., Stirn M., Meli M. L.,
Díaz-Sánchez A., Boretti F. S., Hofmann-Leh-
mann R. 2019. Prevalence, geographic distri-
bution, risk factors and co-infections of feline
gammaherpesvirus infections in domestic cats
in Switzerland. Viruses 11, 721.
Origgi F. C., Plattet P., Sattler U., Robert N., Casau-
bon J., Mavrot F., ... & Ryser-Degiorgis M.-P.
2012. Emergence of canine distemper virus
strains with modified molecular signature and
enhanced neuronal tropism leading to high
mortality in wild carnivores. Veterinary Patho-
logy 49, 913–929.
Panait L.C., Mihalca A.D., Modrý D., Juránková
J., Jonică A. M., Deak G., …& Hrazdilová K.
2021. Three new species of Cytauxzoon in
European wild felids. Veterinary Parasitology
290, 109344.
Pelletier A., Obbard M. E., Harnden M., McConnell
S., Howe E. J., Burrows F. G., White B. N. &
Kyle C. J. 2017. Determining causes of genetic
isolation in a large carnivore (Ursus america-
nus) population to direct contemporary conser-
vation measures. PLOS ONE 12, e0172319.
Pesenti E. & Zimmermann F. 2013. Density esti-
mations of the Eurasian lynx (Lynx lynx) in the
Swiss Alps. Journal of Mammalogy 94, 73–81.
Pisano S. R. R., Zimmermann F., Rossi L., Capt
S., Akdesir E., Bürki R., Kunz F., Origgi F. C. &
Ryser-Degiorgis M.-P. 2019. Spatiotemporal
spread of sarcoptic mange in the red fox (Vul-
pes vulpes) in Switzerland over more than 60
years: lessons learnt from comparative analy-
sis of multiple surveillance tools. Parasites &
Vectors 12, 521.
Ryser-Degiorgis M.-P. 2001. Todesursachen und
Krankheiten beim Luchs – eine Übersicht.
KORA Bericht 8. Muri bei Bern, Switzerland.
19 pp.
Ryser-Degiorgis M.-P. 2009a. Planning of veterina-
ry supervision for translocation programmes of
wild felids. In Iberian lynx ex situ conservation:
an interdisciplinary approach. Vargas A., Brei-
tenmoser-Würsten Ch., Breitenmoser B. (Eds).
Ryser-Degiorgis et al.

The Eurasian lynx in Continental Europe
75
Fundación Biodiversidad / IUCN Cat Specialist
Group. Madrid, Spain, pp. 488–497.
Ryser-Degiorgis M.-P. 2009b. Causes of mortality
and diseases of Eurasian lynx (Lynx lynx). In
Iberian lynx ex situ conservation: an interdis-
ciplinary approach. Vargas A., Breitenmoser-
Würsten C., Breitenmoser B. (eds). Fundaci-
ón Biodiversidad / IUCN SSC Cat Specialist
Group. Madrid, Spain, pp. 274–289.
Ryser-Degiorgis M.-P. 2013. Wildlife health inve-
stigations: needs, challenges and recommen-
dations. BMC veterinary research 9, 223.
Ryser-Degiorgis M.-P. & Segner H. 2015. National
competence center for wildlife diseases in
Switzerland: Mandate, development and cur-
rent strategies. Schweizer Archiv für Tierheil-
kunde 157, 255–266.
Ryser-Degiorgis M.-P., Meli M. L., Zimmermann F
& Lutz H. 2010. First evidence of Cytauxzoon
sp. in Eurasian lynx. In Porceedings of the 9th
Conference of the European Wildlife Disease
Association (EWDA), Vlieland, The Nether-
lands, p. 35.
Ryser-Degiorgis M.-P., Lutz H., Bauer K., Gottstein
B., Ryser A., Zimmermann F., Breitenmoser-
Würsten A. & Breitenmoser U. 2002a. Translo-
cation of lynx within the Swiss Alps: veterinary
supervision. In Proceedings of the 4th scientific
meeting of the EAZWV joint with the biennal
EWDA meeting. Heidelberg, Germany, pp.
147–153.
Ryser-Degiorgis M.-P., Ryser A., Bacciarini L. N.,
Angst C., Gottstein B., Janovsky M. & Brei-
tenmoser U. 2002b. Notoedric and sarcoptic
mange in free-ranging lynx from Switzerland.
Journal of Wildlife Diseases 38, 228–232.
Ryser-Degiorgis M.-P., Ryser A., Obexer-Ruff G.,
Breitenmoser U., Lang J. & Breitenmoser-Wür-
sten C. 2004. Emergence of congenital malfor-
mations in free-ranging lynx from Switzerland:
first evidence of inbreeding depression? In
Proceedings of the 5th scientific meeting of
the European Association of Zoo and Wildlife
Veterinarians (EAZWV). Ebeltoft, Denmark, pp.
307–311.
Ryser A., Scholl M., Zwahlen M., Oetliker M., Ry-
ser-Degiorgis M.-P. & Breitenmoser U. 2005. A
remote-controlled teleinjection system for the
low-stress capture of large mammals. Wildlife
Society Bulletin 33, 721–730.
Ryser-Degiorgis M.-P., Marti I., Pisano S. R. R.,
Wehrle M., Hofmann-Lehmann R., Breiten-
moser U., Origgi F. C., Kübber-Heiss A., Knauer
F. & Meli M. L. 2017. Suspected feline immu-
nodeficiency virus infection in Eurasian lynx
during a translocation program – a veterinary
challenge at the interface among health risks,
species conservation, animal welfare and po-
litics. In Proceedings of the 66th International
Conference of the Wildlife Disease Associati-
on (WDA). San Cristobál de la Casas, Chiapas,
Mexico, p. 27.
Ryser-Degiorgis M.-P., Breitenmoser-Würsten
C., Marti I., Pisano S. R. R., Pewsner M.,
Breitenmoser U & Kovacevic A. 2018. High
prevalence of heart anomalies of suspected
genetic origin in a reintroduced Eurasian lynx
(Lynx lynx) population, Switzerland. In Procee-
dings of the 13th Conference of the European
Wildlife Disease Association (EWDA). Larissa,
Greece, p. 27.
Ryser-Degiorgis M.-P., Robert N., Meier R. K., Zür-
cher-Giovannini S., Pewsner M., Ryser A., …
& Origgi F. C. 2020. Cardiomyopathy associated
with coronary arteriosclerosis in free-ranging
Eurasian lynx (Lynx lynx carpathicus). Frontiers
in Veterinary Science 7, 594952.
Schmidt-Posthaus H., Breitenmoser-Würsten Ch.,
Posthaus H., Bacciarini L. & Breitenmoser U.
2002. Causes of mortality in reintroduced Eu-
rasian lynx in Switzerland. Journal of Wildlife
Diseases 38, 84–92.
Seddon P. J., Griffiths C.J., Soorae P. S. & Arm-
strong D. P. 2014. Reversing defaunation: re-
storing species in a changing world. Science
345, 406–412.
Stahl P. & Vandel J.-M. 2009. Mortalité et cap-
tures de lynx (Lynx lynx) en France (1974-1998).
Mammalia 63, 49–60.
Thüler K. 2002. Spatial and temporal distribution
of coat patterns of Eurasian Lynx (Lynx lynx) in
two re-introduced populations in Switzerland.
KORA Bericht 13e. Muri bei Bern, Switzerland,
35 pp.
Trinkel M., Cooper D., Packer C. & Slotow R. 2011.
Inbreeding depression increases susceptibility
to bovine tuberculosis in lions: an experimental
test using an inbred-outbred contrast through
translocation. Journal of Wildlife Diseases 47,
494–500.
Troyer J. L., Roelke M. E., Jespersen J. M., Baggett
N., Buckley-Beason V., MacNulty D., Craft M.,
Packer C., Pecon-Slattery J. & O’Brien. 2011.
FIV diversity: FIV Ple subtype composition may
influence disease outcome in African lions.
Veterinary Immunology and Immunopathology
143, 338–346.
Valdmann H., Moks E. & Talvik H. 2004. Helminth
fauna of Eurasian lynx (Lynx lynx) in Estonia.
Journal of Wildlife Diseases 40, 356–360.
Vié J. C., De Thoisy B., Fournier P., Fournier-Cham-
brillon C., Genty C. & Kéravec J. 1998. Anes-
thesia of wild red howler monkeys (Alouatta
seniculus) with medetomidine/ketamine and
reversal by atipamezole. American Journal of
Primatology 45, 399–410.
Vogt K., Hofer E., Ryser A., Kölliker M. & Breiten-
moser U. 2016. Is there a trade-off between
scent marking and hunting behaviour in a
stalking predator, the Eurasian lynx, Lynx lynx?
Animal Behaviour 117, 59–68.
Wasieri J., Schmiedeknecht G., Förster C., König
M. & Reinacher M. 2009. Parvovirus infection
in a Eurasian lynx (Lynx lynx) and in a European
wildcat (Felis silvestris silvestris). Journal of
Comparative Pathology 140, 203–207.
Willi B., Filoni C., Catão-Dias J. L., Cattori V., Meli
M. L., Vargas A., Martínez F., Roelke M. E.,
Ryser-Degiorgis M.-P., Leutenegger C. M., Lutz
H. & Hofmann-Lehmann R. 2007. Worldwide
occurrence of feline hemoplasma infections in
wild felid species. Journal of Clinical Microbio-
logy 45, 1159–1166.
Woodford M. H. 2000. Quarantine and health
screening protocols for wildlife prior to
translocation and release into the wild. Pu-
blished jointly by the IUCN Species Survival
Commission’s Veterinary Specialist Group,
Gland, Switzerland, the Office International
des Epizooties (OIE), Paris, France, Care for the
Wild, U.K., and the European Association of
Zoo and Wildlife Veterinarians (EAZWV), Swit-
zerland. 87 pp.
Zimmermann F., Molinari-Jobin A., Ryser A., Brei-
tenmoser-Würsten C., Pesenti E. & Breiten-
moser U. 2011. Status and distribution of the
lynx (Lynx lynx) in the Swiss Alps 2005–2009.
Acta Biologica Slovenica 54, 73–80.
Supporting Online Material SOM Figures F1-F3 are
available at www.catsg.org
1 Centre for Fish and Wildlife Health (FIWI), De-
partment of Infectious Diseases and Pathobiolo-
gy, Vetsuisse Faculty, University of Bern, Switzer-
land
*<marie-pierre.ryser@vetsuisse.unibe.ch>
2 Clinical Laboratory, Department of Clinical Di-
agnostics and Services, and Center for Clinical
Studies, Vetsuisse Faculty, University of Zurich,
Winterthurerstrasse 260, 8057 Zürich, Switzer-
land
3 KORA Carnivore Ecology and Wildlife Manage-
ment, Muri b. Bern, Switzerland
health surveillance of Eurasian lynx