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Assessment of risk factors of Dirofilaria immitis infection and results of multiple Generalized Linear Model (GLM) for the risk factors driving Dirofilaria immitis
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Background
The nematodes Dirofilaria immitis and D. repens are enzootic in Greece. In the light of evidence of dirofilariosis spreading to new areas around the world, the aim of the present study was to update and enrich the current knowledge on the prevalence of Dirofilaria infections in dogs in Greece, to assess the risk factors of heartworm infe...
Contexts in source publication
Context 1
... the statistical analysis of the risk factors of D. immitis infection (Table 3), the municipality where the dog lived, its usage and its age were the most im- portant risk factors (Chi-square test of independence for municipality: χ 2 = 40.22, df = 4, P < 0.001; for usage: χ 2 = 27.51, ...
Context 2
... the other hand, factors gender, breed, hair length, body size, living together with other animals, water collections and type of vegetation in the area were not associated with higher risk of infection. The statisti- cally significant characteristics by the Chi-square test were entered in the multiple GLM showing the same statistically significant results (Table 3). ...
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Background
During the last decades, filarial infections caused by Dirofilaria spp. have spread rapidly within dog populations of several European countries. Increasing scientific interest in filariasis, and the availability of new diagnostic tools, has led to improved knowledge of the biology, morphology, and epidemiology of different species of fi...
Citations
... It should be noted that no distinct border exists dividing enzootic and non-enzootic areas. However, according to the published data originating from different parts of Greece and to the veterinary perception, regions below Thessaly and Epirus and above the northern parts of Central Greece are considered the border between enzootic and non-enzootic areas [12,13]. In particular, epizootiological surveys have recorded prevalence rates ranging from 6.75% up to 68% for D. immitis infection in dogs living in the northern areas of Greece, i.e., Macedonia, Thrace, Epirus, and Thessaly [12][13][14][15][16][17][18][19][20]. ...
... However, according to the published data originating from different parts of Greece and to the veterinary perception, regions below Thessaly and Epirus and above the northern parts of Central Greece are considered the border between enzootic and non-enzootic areas [12,13]. In particular, epizootiological surveys have recorded prevalence rates ranging from 6.75% up to 68% for D. immitis infection in dogs living in the northern areas of Greece, i.e., Macedonia, Thrace, Epirus, and Thessaly [12][13][14][15][16][17][18][19][20]. Concerning the regions of Greece that were regarded as non-enzootic (Central Greece, Attica, Peloponnese, North Aegean, South Aegean, Crete, and the Ionian islands), the recorded prevalence rates from studies up to 2022 ranged from 0% in Crete up to 10.9% in the Ionian islands [12,13,19,21]. ...
... In particular, epizootiological surveys have recorded prevalence rates ranging from 6.75% up to 68% for D. immitis infection in dogs living in the northern areas of Greece, i.e., Macedonia, Thrace, Epirus, and Thessaly [12][13][14][15][16][17][18][19][20]. Concerning the regions of Greece that were regarded as non-enzootic (Central Greece, Attica, Peloponnese, North Aegean, South Aegean, Crete, and the Ionian islands), the recorded prevalence rates from studies up to 2022 ranged from 0% in Crete up to 10.9% in the Ionian islands [12,13,19,21]. ...
Although Dirofilaria immitis in dogs is considered enzootic in northern Greece, the available data on the occurrence of infection in southern parts of the country demonstrate its scarcity. The aim of this study was to update the current knowledge on D. immitis infection in dogs in areas of Greece previously considered non-enzootic (Central Greece, Attica, Peloponnese, North Aegean, South Aegean, Crete and the Ionian islands). In total, 1528 dog blood samples were collected from the aforementioned areas and examined by Dirochek® ELISA (Synbiotics). Additionally, data published until 2022 on the prevalence of infection in these areas were compared to the data of this study. The ‘Wilson’ Score interval method (Epitools) was employed. Overall, 10.8% of dogs were positive for D. immitis. In detail, the prevalence was 21.7, 13.7, 10.7, 5.4, 4.7, 6.2 and 17.0% for D. immitis, in Central Greece, Attica, Peloponnese, North Aegean, South Aegean, Crete and the Ionian islands, respectively. Infection with D. immitis is recorded for the first time in Crete. The probability of a dog becoming infected has increased 4.1 times since 2022 in previously non-enzootic areas. This study denotes the spread of D. immitis and highlights the necessity for preventive measures.
... Dirofilaria spp. are enzootic in many European countries but are more prevalent in the south, where the prevalence of infection in dogs is particularly high in some areas (eg northern Italy, northern Greece, Canary Islands) (Montoya et al, 1998;Genchi et al, 2011;Diakou et al, 2016a). Imported filarial infections, caused by D. immitis and D. repens, have attracted the attention of scientists as these parasites show a clear distribution expansion tendency in Europe (Alsarraf et al, 2021;Morchón et al, 2022). ...
In the modern world, country borders do not represent boundaries for the transmission of pathogens. This is also true for parasites that may travel with animals, particularly pets. Dogs and cats are moving across countries more than ever before as a result of adoption, commerce and travels with owners. In addition, climate change supports the establishment of parasites, particularly those transmitted by invertebrate intermediate hosts and vectors, into areas which were previously considered non-enzootic. Therefore, it is important for veterinarians to keep a vigilant eye on such parasitic infections in dogs and cats, be able to recognise compatible signs and feel confident in ordering specific diagnostic tests. This article presents parasites prevalently reported as imported from one European country to another. Furthermore, common clinical manifestations and diagnostic tests are summarised and the preventive measures that should be advised to pet owners are discussed. Raising awareness among veterinary practitioners and pet owners about the risk of parasites spreading in new areas is imperative for controlling and delaying globalisation of important, and potentially lethal, parasitic diseases.
... Greece is one of the countries where the disease is traditionally endemic and has continued to spread countrywide. Different studies have reported a mean prevalence close to 9% for D. immitis in domestic dogs (Diakou et al., 2016(Diakou et al., , 2019Angelou et al., 2019;Genchi and Kramer, 2020). In the northern part of the country, prevalence ranges from 6.1% to 26.8%, with the highest prevalence in areas bordering Bulgaria and the lowest near Albania. ...
... The same weight was assigned to the 2 layers (50%) to evaluate both the ecological niche of Cx. pipiens as the number of generations of the parasite in the vector, and thus obtain an integrative model Rodríguez-Escolar et al., 2023). To validate the obtained risk map, georeferenced points of D. immitis-infected dogs were collected from all over the country (Diakou et al., 2016;Angelou et al., 2019) and superimposed on the map. ...
... Map of the risk of Dirofilaria spp. infection in Greece with the geolocations of infected dogs, according toDiakou et al., 2016;Angelou et al., 2019. ...
... Dirofilariosis cases are most frequently reported in southern European and Mediterranean countries. Greece, especially, is considered to be endemic for canine cardiac dirofilariosis, with its northern areas recording high prevalence of infection by D. immitis (Tolnai et al. 2014;Diakou et al. 2016). Although patent infections are most commonly described in domestic dogs (Ionică et al. 2022), the primary domestic reservoirs of D. immitis, the parasite has also been documented in a large variety of wild mammals, including red foxes (Vulpes vulpes Linnaeus, 1758), golden jackals (Canis aureus Linnaeus, 1758), European wildcats (Felis silvestris silvestris Schreber, 1777), and wolves (Canis lupus Linnaeus, 1758). ...
Dirofilaria immitis is a ubiquitous nematode parasite with zoonotic potential, transmitted by mosquitoes, that causes heartworm disease in various animal species. Dogs are the parasite’s typical final host, and wild carnivores represent the parasite’s reservoir in nature. Studies on D. immitis infections in wild animals are essential to assess infection pressure for domestic animals, and until now, there has been only one infection case reported in a European badger (Meles meles). The current report describes the first two European badger cases with cardiovascular dirofilariosis in Greece. Two adult male badgers were rescued in Heraklion and Chania, Crete Island, and admitted to “ANIMA -Wildlife Rehabilitation Centre” in Athens. The detailed clinical examination revealed that the first badger suffered from severe broncho-pneumonitis while the second one displayed clinical signs associated with severe brain trauma. Blood samples were taken for haematology and biochemistry analyses during their short hospitalisation period. In addition, different routine diagnostic tests were carried out, including heartworm antigen testing (ELISA) and the modified Knott’s test for microfilariae. Both badgers were positive in both tests. The animals died a few hours after their admission and the detailed necropsies followed, revealed the presence of three parasites in each animal’s right heart, morphologically identified as adults of D. immitis. These findings add the European badger in the list of additional potential reservoir hosts for D. immitis and highlight the potential role of wildlife for companion animals and human health.
... These associations suggest that canines of short hair are at higher infection risk for D. immitis. Other studies differ with our results, where the long hair variable did not present statistical differences and was not presented as a risk factor for D. immitis(Diakou et al. 2016;Muñoz et al. 2020).Regarding the variable age, only the category less than one year old presented a statistical signi cance for Anaplasma spp. These ndings are consistent with those reported by Bonilla et al. (2020), who observed that infection for Anaplasma spp. was higher in young dogs and could be associated with lower levels of T cells CD8 + observed in young dogs(Greeley et al. 1996), that would be necessary for the destruction of microorganisms such as rickettsia(Walker et al. 2015). ...
Canine vector-borne pathogens are found in many regions and represent a challenge for animal health. Shelter dogs are found to be an important health and ecological factor in urban areas in Colombia. Therefore, the aim of the present research was to determine the seroprevalence of canine vector-borne pathogens in shelter dogs from the Metropolitan Area of Bucaramanga, Santander, Colombia. An IDEXX SNAP® 4Dx Plus assay was employed to test 278 shelter dogs. From each dog, the following data were collected: municipality, age, gender, and coat length. Overall, 81.3% of the tested dogs were positive for one or more of the vector-borne pathogens. The highest prevalence observed was for Ehrlichia spp. (79.9%) in 278 shelter dogs, followed by Anaplasma spp. (36%), Dirofilaria immitis (6.5%) and Borrelia burgdorferi (2.2%). Regarding the variable age, dogs less than one year old showed a statistical association ( P = 0.02) for Anaplasma spp., and short-haired dogs showed a statistical association ( P = 0.03) for D. immitis . The present study provides current information on the seroprevalence of vector-borne pathogens in shelter dogs from the Metropolitan Area of Bucaramanga, and these findings could be useful for control measures that should be implemented on dog populations and vector populations in the study area.
... Age has been reported as a risk factor for filarial infection in dogs (37), most likely related to the accumulation of transmission periods and, subsequently, opportunities for an infection to occur in hosts not under preventive treatment. However, in this study, age could not be identified as a risk factor for filarial infection, likely because all the animals were older than two years in age (38) compared to other studies where age ranges typically started before one year of age. ...
... Infections caused by A. reconditum exhibit distinct epidemiological features compared with those caused by Dirofilaria species. The distinctive attributes of factors influencing the transmission and establishment of Dirofilaria spp. in different regions, including the presence of reservoir hosts and the abundance and stability of vectors, ultimately shape their epidemiology (38). ...
Climate change, competent vectors, and reservoir animals are the main factors for developing vector-borne zoonotic diseases. These diseases encompass a significant and widespread category of pathogens (e.g., viruses, bacteria, protozoa, and helminths) transmitted by blood-feeding arthropods, including ticks, fleas, lice, triatomines, mosquitoes, sandflies, and blackflies. In Chile, several studies have explored the role of dogs as reservoirs of vector-borne pathogens; however, there is a lack of research investigating the presence of pathogens in arthropods. Specifically, within the order Diptera, limited knowledge exists regarding their roles as carriers of pathogens. This study aimed to examine the presence of zoonotic filarial nematodes in mosquitoes and dogs within a previously unstudied semi-rural area of Central Chile. Two hundred samples of dog blood and seven hundred and twenty-four mosquitoes were collected during 2021–2022 and studied for filarial nematodes by PCR. The prevalence of microfilaremic dogs detected by Knott’s test was 7.5%, with Acanthocheilonema reconditum being the only species identified. Aedes (Ochlerotatus) albifasciatus was the most abundant mosquito species collected, and 15 out of 65 pools were positive for filarial nematodes. Among these pools, 13 tested positive for Acanthocheilonema reconditum, and two tested positive for Setaria equina through PCR. Additionally, five Culex pipiens specimens were positive for Acanthocheilonema reconditum. Despite the absence of zoonotic filarial species, these findings underscore the significance of monitoring pathogens in mosquitoes and animal hosts and continued research into the dynamics of vector-borne diseases, particularly in unexplored regions.
... herein detected represented exposure to E. canis, as this is the only species occurring in dogs in Europe, and due to the vast distribution of its main vector, Rhipicephalus sanguineus. Northern Greece historically displays the highest seroprevalence of D. immitis compared to the rest of the country [42]. Despite preventive treatments being applied in most owned dogs in Northern Greece [43], a combination of factors, e.g., wetlands, mosquito populations, stray dogs and wildlife abundance (e.g., foxes, jackals, wolves), result in this epizootiological scenario [42,44]. ...
... Northern Greece historically displays the highest seroprevalence of D. immitis compared to the rest of the country [42]. Despite preventive treatments being applied in most owned dogs in Northern Greece [43], a combination of factors, e.g., wetlands, mosquito populations, stray dogs and wildlife abundance (e.g., foxes, jackals, wolves), result in this epizootiological scenario [42,44]. ...
... Such a marked difference in the seropositivity rate of CVBD pathogens in dogs from Italy and Greece was not detected in recent studies; by contrast, a similar occurrence of CVBDs was reported [11,30]. The discrepancy is likely due to the geographic area herein studied, i.e., Northern and Northeastern Greece, where CVBDs are significantly more preva-lent than in other areas of the country, probably due to environmental drivers [15,40,42], while the previous study was conducted in Aegean islands, where no differences with the seroprevalence rates in Italy were detected [11]. Furthermore, in the present study, in Italy, almost only urban dogs were enrolled, while most of the dogs enrolled in Greece were from towns located in rural areas that lived outdoors, i.e., gardens and yards, and in environments where the presence of vectors and the infection pressure by CVBD pathogens is particularly high. ...
Canine Vector-Borne Diseases (CVBDs) are widespread in Europe and enzootic in many other countries. Though severe illnesses may occur, dogs living in enzootic areas often show vague or no clinical signs of CVBDs. Undiagnosed infections/co-infections in subclinically infected animals favor the spread of CVBDs and increase the risk of transmission to other animals and, in some cases, humans. This study has evaluated the exposure of dogs living in key enzootic countries, i.e., Italy and Greece, to major CVBDs via the use of in-clinic diagnostic kits. Overall, 300 privately owned dogs without/with single mild clinical signs living in different regions of Italy (n. 150) and Greece (n. 150) were included in the study. As part of a clinical examination, a blood sample was collected from each dog and subjected to two serological rapid tests, i.e., the SNAP® 4Dx®Plus (IDEXX Laboratories Inc.) for the detection of antibodies against Ehrlichia spp., Anaplasma spp., Borrelia burgdorferi s.l. and Dirofilaria immitis antigen and the SNAP® Leishmania (IDEXX Laboratories Inc.) for the detection of antibodies against Leishmania infantum. In all, 51 dogs (17%; 95% CI 12.9–21.7) were seropositive to at least 1 pathogen, i.e., 4 in Italy (2.7%; 95% CI 1.4–13.1) and 47 in Greece (31.3%; 95% CI 24–39.4). Dirofilaria immitis antigens were found in 39 dogs (13%; 95% CI 9.4–17.3), while antibodies against Ehrlichia, Anaplasma and Leishmania were detected in 25 (8.3%; 95% CI 5.5–12.1), 8 (2.7%; 95% CI 1.2–5.2) and 5 (1.7%; 95% CI 0.5–3.8) dogs, respectively. None of the dogs tested seropositive for B. burgdorferi s.l. Statistical analyses were performed to evaluate associations between exposure to CVBDs and possible risk factors. The present results indicate that dogs living in enzootic areas may be seropositive for one or more CVBDs in absence of clinical signs. Rapid kits are among first line tools for the detection of CVBDs in clinical settings, as they are cost-effective, straightforward and quick to use. Also, in-clinic tests used herein allowed detection of co-exposure to CVBDs investigated.
... Finally, to support this evaluation, statistical analysis was performed for PRW infections on the considered palm trees. The risk factor affecting RPW occurrence was determined using the Chisquare test of independence between the status of each palm (infested or dead; health) and a different treatment (chemical treatment yes or not) (Diakou et al. 2016). The Chi-square testing was securely performed as his assumptions were respected: no more than 20% of the cells can have an expected frequency less than five (in mean 1845.75), ...
The implications related to the fight against alien organisms often affect different sectors, from the economic to the landscape one or from the public health to the ecological one. This paper is an upgrade of our previous study focused on the evolution of the red palm weevil in a coastal urban area (central Italy); we investigate the evolution of this parasite in the following period (2013-2020), considering both the effectiveness of the chemicals used and their potential effects. With a multidisciplinary approach, on the one hand we carried out a spatio-temporal analysis to analyze the extent and mode of pest spread over time using historical aerial photos, freely available remote sensing images and field surveys, integrated in a GIS environment, and on the other hand we performed an assessment of the chemical risk associated with the substances used to protect the palms from the red weevil. The fight against weevil is now concentrated in specific areas (parks, relevant roads, villas, hotels, farmhouses, nurseries); the applied preventive chemical treatments are very effective in preserving the palms, but they show a toxic potential for all organisms. We discuss current local management of this pest focusing on the several aspects involve into the fight against this beetle in an urban area.
... Дослідження із застосуванням методу Нотта та серології, проведені у Греції, вказують на ураження 31 (4,1 %) з 750 дослідних тварин збудником Dirofilaria immitis [14]. ...
У роботі наведено узагальнені дані щодо поширеного нематодозного захворювання собак (Canis lupus familiaris Linnaeus, 1758), спричиненого збудниками Dirofilaria spp., в умовах міста Миколаєва. Останні представляють інтерес як для лікарів гуманної, так і ветеринарної медицини. Дирофіляріоз відносять до небезпечного трансмісивного захворювання зоонозного характеру. Збудників хвороби відносять до класу круглих гельмінтів Chromadorea, підряду Spirurina, родини Onchocercidae, роду Dirofilaria. Вони є надзвичайно поширеними у багатьох країнах світу і пристосованими до існування в різних кліматичних зонах, цьому сприяє складна біологія розвитку паразитів. Метою дослідження було визначити епізоотологічні особливості дирофіляріозної інвазії собак за даними ветеринарної клініки «Велес» міста Миколаєва, а також проаналізувати клінічний прояв хвороби. Для виявлення личинкової стадії збуднику хвороби в умовах клініки здійснено діагностичні гемоларвоскопічні дослідження 123 собак. Досліджували тварин, підозрюваних у захворюванні на дирофіляріоз, що належали мешканцям м. Миколаєва. Вік тварин – від 1 до 14 років. Встановлено, що ураженість собак Dirofilaria spp. становить 19,51 % за умови середньої інтенсивності інвазії – 58,3±3,22 лич./см3. Згідно з отриманими результатами щодо вікової динаміки дирофіляріозу у собак відмічено, що з віком кількість уражених тварин збільшується. Відповідно, найменший відсоток захворюваності (8,33 %) припадає на собак до дванадцяти місяців. У групі тварин віком від 1 до 6 років становить – 33,33 %. Найбільш ураженими збудниками дирофіляріозної інвазії виявилися собаки у віці 6–12 років, де показник екстенсивності інвазії склав 45,83 %. Зважаючи на те, що клінічні симптоми цього захворювання можуть бути неспецифічними, вирішальне значення у діагностиці мають лабораторні аналізи на виявлення мікрофілярій у крові. Проаналізовано, що у клініку зверталися господарі собак, у яких домінували перший (45,8 %) та другий клас (41,7 %) клінічного перебігу захворювання. З’ясовано, що найбільш сприйнятливими до збудників дирофіляріозу є безпородні тварини та собаки породи ротвейлер і німецька вівчарка (ЕІ – 37,5 та 20,8 % відповідно). У дослідженні не зафіксовано закономірностей щодо статевої сприйнятливості тварин до захворювання.
... 16% in Poland(Krämer et al., 2014), 27.3% in Portugal(Vieira et al., 2014), 8.28% in Mexico (Bolio-Gonzalez et al., 2007, 30.3% in Iran(Anvari, Saadati, Siyadatpanah, & Gholami, 2019), 4.1% in Greece(Diakou, Kapantaidakis, Tamvakis, Giannakis, & Strus, 2016) and 52.18% in Spain(Montoya, Morales, Ferrer, Molina, & Corbera, 1998) prevalence were reported. ...
