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Pesq. Vet. Bras. 37(12):1380-1384, dezembro 2017
DOI: 10.1590/S0100-736X2017001200004
1380
RESUMO.- [Reações falso-negativas ao teste cervical
comparativo para tuberculose bovina.] No Brasil, se-
gundo o Programa Nacional de Controle e Erradicação da
Brucelose e Tuberculose Animal (PNCEBT), do Ministério
da Agricultura, Pecuária e Abastecimento (MAPA), os testes
de rotina para o diagnóstico de tuberculose bovina são o
teste cervical simples (TCC), o teste da prega caudal (TPC)
e o teste cervical comparativo (TCC), sendo que o último
53 animais oriundos de três rebanhos leiteiros de área de
foco para tuberculose bovina que foram submetidos a vazio
tecidos destes animais foram cultivados e as colônias resul-
53 animais analisados no TCC, 32 (60,4%) foram negativos,
14 (26,4%) positivos e sete (13,2%) inconclusivos, com
False-negative reactions to the comparative intradermal
tuberculin test for bovine tuberculosis1
2325,
4, Walter Lilenbaum67 and 4*
ABSTRACT.-
False-negative reactions to the comparative intrader-
mal tuberculin test for bovine tuberculosisPesquisa Veterinária Brasileira 37(12):1380-
1384.
E-mail:
According to the Brazilian National Program for the Control and Eradication of Animal
Brucellosis and Tuberculosis (PNCEBT), the routine tests for the diagnosis of bovine tu-
berculosis in the country are the simple intradermal tuberculin test (SITT) of the Ministry
-
group of 53 animals from three dairy herds in a focal area for bovine tuberculosis, that
were submitted to depopulation in the state of Rio Grande do Sul, were submitted to the
M. bovis
-
nance of these false-negative animals in herds has serious implications for the control of
Mycobacterium bovis, Comparative
2
-
3 Programa de Pós-Graduação em Biotecnologia e Biodiversidade da Re-
4 Laboratório de Imunologia, Sanidade Animal, Embrapa Gado de Corte,
Avenida Rádio Maia 830, Zona Rural, Campo Grande, MS 70106-550, Bra-
5
6 -
7 Secretaria da Agricultura, Pecuária e Irrigação, Avenida Getúlio Vargas
Pesq. Vet. Bras. 37(12):1380-1384, dezembro 2017
1381False-negative reactions to the comparative intradermal tuberculin test for bovine tuberculosis
animais com infecção por M. bovis
-
tou, para a população amostrada, sensibilidade de 28,2%
-
manutenção destes animais falso-negativos nos rebanhos
bovina, Mycobacterium bovis, Teste Cervical Comparativo, cultura
INTRODUCTION
Bovine tuberculosis (bTB) is a chronic infectious disease
caused by the intracellular bacterium Mycobacterium bovis,
which affects many domestic and wild species, especially
cattle and buffalo, and causes disease in humans (Pesciaroli
-
alth and causes economic losses, due mainly to the culling
is a commercial barrier to the export of meat from Brazil
In several countries, bTB control programs involve the
detection and culling of infected animals based on the in-
tradermal test, which measures the delay in hypersensitivi-
ty elicited by the inoculation of the mycobacterial antigen,
intradermal testing is the standard recommended method
for the diagnosis of M. bovis
-
-reactions with species of non-tuberculous mycobacteria
-
sitivity due to the occurrence of animals in advanced stages
Therefore, the consensus is that the intradermal test alone
may not be able to detect all animals infected with M. bovis,
eradication of bovine tuberculosis in several parts of the
world, reports of persistent outbreaks of the disease re-
main frequent even after the implementation of such pro-
cattle into herds, transmission by wild animals or a failure
in detecting all infected animals, which can remain as re-
In Brazil, according to the National Program for the
Control and Eradication of Animal Brucellosis and Tuber-
culosis (Programa Nacional de Controle e Erradicação da
Brucelose e Tuberculose Animal - PNCEBT) of the Ministry
-
commended tests for the routine diagnosis of bTB are the
simple intradermal tuberculin test (SITT), the caudal fold
-
mals showing a difference in skin fold enhancement caused
M. bovis M.
avium
-
wever, cross-reactions with environmental mycobacteria
can sensitize animals, leading to positive results on the in-
CITT and reduce the occurrence of false-positive reactions
may have low sensitivity and not be able to identify truly
the occurrence of false-negative CITT reactions in infected
-
monstrated through the bacteriological culture of lesions
-
-
MATERIALS AND METHODS
Study design.
2014 and March 2015 with three dairy cattle herds from the mu-
nicipalities of Arroio do Meio and Bom Retiro do Sul in the micro-
-
gardless of the results of the intradermal test, all animals were slau-
ghtered and submitted to necropsy, following the determination of
Myco-
bacterium bovis
Brazil
Pesq. Vet. Bras. 37(12):1380-1384, dezembro 2017
1382 Rudielle A. Rodrigues et al.
Herds and animals. Two of the three herds studied were ac-
credited as being free of bTB: herd A since 2010 and herd B since
test resulted in the detection of positive animals in the three her-
-
pulated (38 animals in herd A, seven animals in herd B and eight
Intradermal test. The CITT was performed according to the
-
-
-
with the evaluation of the delayed hypersensitivity reaction at the
-
-
Samples. All animals from infected herds were slaughtered
slaughtered under the supervision of the veterinary inspection
retropharyngeal, intramammary, pulmonary and mesenteric lym-
ph nodes with or without macroscopic lesions compatible with
tuberculosis (granulomas usually with a yellowish appearance
-
tive of tuberculosis, hepatic, mediastinal, mesenteric, retropha-
tissue samples were placed separately in sealed plastic bags, in-
dicating the number of the animal and the name of the organ col-
two or three sets of tissues, indicating the numbers of the animals
the samples were frozen for later shipment under refrigeration
in a thermal insulation box, which was placed in a cardboard box
indicating that it was an infective material, in compliance with the
standards established by Packaging Instruction P/650-IATA (In-
Mycobacterium bovis. Tissue
perimetric tissues (between 10 and 25mg) were macerated with
Life Science), decontaminated using the Petroff method (Mako-
M. bovis were sub-
-
all the other members of the Mycobacterium tuberculosis Complex
DNA sequencing. -
-
Local alignment of DNA sequences. The base calling of the
-
were compared to the nr/nt database bank by Blastn (https: //
Statistical analysis. The level of agreement between each
exact tests, which determine whether or not paired proportions
used to measure the degree of linear correlation between the two
measures, obtained pairwise per animal: M. bovis and M. avium
RESULTS
In the analysis of the 53 cattle, the CITT detected 14
tuberculosis (LST) were detected in organs/tissues of 43
-
discrepancy between the CITT results and the presence of
-
ce of discordant pairs of LST positive and CITT negative
-
M. bovis
-
M. bovis
Among the total of 14 uninfected animals based on culture,
-
-
All colonies suggestive of M. bovis
fragment resulting from the M. bovis-
-
-
Table 1. Results of comparative intradermal cervical test
(CITT), presence of lesions suggestive of tuberculosis (LST)
and bacteriological culture of cattle from the Lajeado-
Estrela micro-region, Rio Grande do Sul, Brazil
CITT results LST +/ LST +/ LST -/ LST -/ Total
culture + culture - culture + culture-
CITT + 11 2 0 1 14
CITT - 24 1 0 7 32
CITT inconclusive 4 1 0 2 7
Pesq. Vet. Bras. 37(12):1380-1384, dezembro 2017
1383False-negative reactions to the comparative intradermal tuberculin test for bovine tuberculosis
ces all presented the homologous fragment in the isolate
M. bovis -
-
tween the presence of LST and the occurrence of positive
culture for M. bovis
The apparent prevalence of bTB in the herds studied was
DISCUSSION
In Brazil, the only methods recommended by the National
Program for the Control and Eradication of Brucellosis and
Animal Tuberculosis (PNCEBT) for the antemortem diag-
simple intradermal tuberculin test (SITT) and cervical
program, the latter test, which was previously considered a
-
M. bovis infection predominantly triggers a cell respon-
se in the initial and intermediate stages of infection coor-
-
le CITT simultaneously tests the intradermal responses to
-
ze animals and therefore affect the results of intradermal
-
precisely because it detects possible cross-reactions to en-
-
ghter of animals and bacteriological tissue cultures have
Thus, there is consensus on the usefulness of CITT as a con-
M. bovis
sensitivity of the CITT and its use as a screening method,
often reported to be unsatisfactory, with mean estimates of
-
ness of the CITT as a screening method for M. bovis infection
Sanitary depopulations, in which the entire herd is slau-
ghtered after failure to control bTB, are unique opportu-
nities to evaluate quality parameters of intradermal tests,
since positive and negative culture data are generated (Ka-
study, allowing the comparison of intradermal reactions to
-
-
ce LST was detected in several animals with negative CITT
M. bovis culture,
which lends support to the recommendation that slaughte-
red animals with suspected bTB should always be submit-
M. bovis
results, most presented LST and M. bovis positive cultures,
which lends support to the recommendation that animals
with inconclusive results on farms with outbreaks of bTB
may exhibit positive results with the progression of the di-
of the 32 animals with negative CITT results presented LST
-
herds, such animals would have been considered negative
and would maintain the infection in the herd, spreading it
other regions may also occur, since infected animals could
that two of the three herds examined had been accredited
-
gion studied and the CITT, although still an excellent con-
-
-
-
mal with negative results had a positive culture for M. bovis
tests, there is no recommendation for additional tests in
-
ten not slaughtered and further investigation is hampered
-
though attempts at direct diagnosis from live animal sam-
-
The inability to identify all infected animals impairs
false-negative CITT reactions led to the failure to control
use of different in vivo diagnostic tests, such as interferon-
-gamma for the detection of the cellular immune response
-
rological tests, such as ELISA, for the detection of the hu-
increase the diagnostic coverage of intradermal tests and
reduce the impact of failed diagnoses on the control of bTB
Pesq. Vet. Bras. 37(12):1380-1384, dezembro 2017
1384 Rudielle A. Rodrigues et al.
CONCLUSIONS
The CITT demonstrated low sensitivity in the diagnosis
of bTB, leading to a high percentage of animals with false-
The maintenance of these false-negative animals in her-
ds has serious implications for the control of the disease,
The addition of complementary tests could help identi-
Acknowledgements.- To Ministério da Ciência, Tecnologia e Inova-
G-
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