Importance of CDV infection in free-ranging Iberian lynxes

Meli, M. L., Simmler, P., Cattori, V., Martínez, F., Vargas, A., Palomares, F., ... & Hofmann-Lehmann, R. (2010). Importance of canine distemper virus (CDV) infection in free-ranging Iberian lynxes (Lynx pardinus). Veterinary microbiology, 146(1), 132-137.

Canine distemper virus (CDV) is a morbillivirus that is the etiological agent of one of the most important viral diseases affecting canids and an expanding range of other carnivores. Using real-time RT-PCR, CDV RNA was detected in organs of an Iberian lynx (Lynx pardinus) found dead in the Doñana National Park, Southwestern Andalusia, Spain. This finding may be of great importance for the conservation of the species; at present the Iberian lynx is the most critically endangered wild felid. The aim of the present study was to elucidate the significance of CDV for the Iberian lynx population. High viral loads were evident in the dead lynx, suggesting an etiological involvement of CDV in its death. When carnivores from the same region were analyzed by CDV RT-PCR, a stone marten (Martes foina) was positive. Phylogenetic analyses demonstrated high identity of the two detected CDVs and a close relationship to the European dog lineage of CDV. Antibodies to CDV were detected in 14.8% of 88 tested free-ranging Iberian lynxes. The sample seroprevalence was significantly higher in lynxes from the Doñana Natural Space (22.9%) than Sierra Morena (5%). The stone marten and a red fox (Vulpes vulpes) also tested seropositive. In conclusion, CDV is present in the Iberian lynx population, especially in the Doñana region, with sporadic cases of disease. To reduce the infectious pressure of CDV on this endangered population, a mass dog vaccination should be considered.

Exposure of Free-Ranging Wild Carnivores and Domestic Dogs to CDV and Parvovirus in Central Brazil

Furtado, M. M., Hayashi, E. M. K., Allendorf, S. D., Coelho, C. J., de Almeida Jácomo, A. T., Megid, J., ... & Neto, J. S. F. Exposure of Free-Ranging Wild Carnivores and Domestic Dogs to Canine Distemper Virus and Parvovirus in the Cerrado of Central Brazil. EcoHealth, 1-9.

Human population growth around protected areas increases the contact between wild and domestic animals, promoting disease transmission between them. This study investigates the exposure of free-ranging wild carnivores and domestic dogs to canine distemper virus (CDV) and parvovirus in Emas National Park (ENP) in the Cerrado savanna of central Brazil. Serum samples were collected from 169 wild carnivores, including the maned wolf (Chrysocyon brachyurus), crab-eating fox (Cerdocyon thous), hoary fox (Pseudalopex vetulus), puma (Puma concolor), ocelot (Leopardus pardalis), pampas cat (Leopardus colocolo), jaguarundi (Herpailurus yagouaroundi), striped hog-nosed skunk (Conepatus semistriatus) and coati (Nasua nasua), and from 35 domestic dogs living on rural properties bordering ENP. Serological tests showed that 10.6% of wild carnivores (maned wolves, crab-eating foxes and ocelots) and 71.4% of domestic dogs were exposed to CDV, and 56.8% of wild carnivores, including all species sampled except coatis, and 57.1% of domestic dogs were exposed to parvovirus. This report is the first to indicate that the free-ranging pampas cat, jaguarundi and striped hog-nosed skunk are exposed to parvovirus. CDV and parvovirus deserve attention in ENP, and it is extremely important to monitor the health of carnivore populations and perform molecular diagnosis of the viruses to determine the possible involvement of the domestic dog in their transmission.

CDV in wild endangered Amur tigers

Seimon, T. A., Miquelle, D. G., Chang, T. Y., Newton, A. L., Korotkova, I., Ivanchuk, G., ... & McAloose, D. (2013). Canine distemper virus: an emerging disease in wild endangered Amur tigers (Panthera tigris altaica). MBio, 4(4), e00410-13.


Fewer than 500 Amur tigers (Panthera tigris altaica) remain in the wild. Due to low numbers and their solitary and reclusive nature, tiger sightings across their range in the Russian Far East and China are rare; sightings of sick tigers are rarer still. Serious neurologic disease observed in several wild tigers since 2001 suggested disease emergence in this endangered species. To investigate this possibility, histology, immunohistochemistry (IHC), in situ hybridization (ISH), and reverse transcription-PCR (RT-PCR) were performed on tissues from 5 affected tigers that died or were destroyed in 2001, 2004, or 2010. Our results reveal canine distemper virus (CDV) infection as the cause of neurologic disease in two tigers and definitively establish infection in a third. Nonsuppurative encephalitis with demyelination, eosinophilic nuclear viral inclusions, and positive immunolabeling for CDV by IHC and ISH were present in the two tigers with available brain tissue. CDV phosphoprotein (P) and hemagglutinin (H) gene products were obtained from brains of these two tigers by RT-PCR, and a short fragment of CDV P gene sequence was detected in lymph node tissue of a third tiger. Phylogenetically, Amur tiger CDV groups with an Arctic-like strain in Baikal seals (Phoca siberica). Our results, which include mapping the location of positive tigers and recognition of a cluster of cases in 2010, coupled with a lack of reported CDV antibodies in Amur tigers prior to 2000 suggest wide geographic distribution of CDV across the tiger range and recent emergence of CDV as a significant infectious disease threat to endangered Amur tigers in the Russian Far East.

IMPORTANCE Recognition of disease emergence in wildlife is a rare occurrence. Here, for the first time, we identify and characterize a canine distemper virus (CDV), the second most common cause of infectious disease death in domestic dogs and a viral disease of global importance in common and endangered carnivores, as the etiology of neurologic disease and fatal encephalitis in wild, endangered Amur tigers. We establish that in 2010 CDV directly or indirectly killed ~1% of Amur tigers. Location of positive cases over an expansive geographic area suggests that CDV is widely distributed across the tiger range. Interspecies interactions are increasing as human populations grow and expand into wildlife habitats. Identifying animal reservoirs for CDV and identifying the CDV strains that are transmissible to and among wildlife species, including Amur tigers and sympatric critically endangered Amur leopards (Panthera pardus orientalis), is essential for guiding conservation and mitigation efforts.

Cross-species transmission of CDV

Beineke, A., Baumgärtner, W. & Wohlsein, P. 2015. Cross-species transmission of canine distemper virus-an update. One Health 1, 49–59.

Canine distemper virus (CDV) is a pantropic morbillivirus with a worldwide distribution, which causes fatal disease in dogs. Affected animals develop dyspnea, diarrhea, neurological signs and profound immunosuppression. Systemic CDV infection, resembling distemper in domestic dogs, can be found also in wild canids (e.g. wolves, foxes), procyonids (e.g. raccoons, kinkajous), ailurids (e.g. red pandas), ursids (e.g. black bears, giant pandas), mustelids (e.g. ferrets, minks), viverrids (e.g. civets, genets), hyaenids (e.g. spotted hyenas), and large felids (e.g. lions, tigers). Furthermore, besides infection with the closely related phocine distemper virus, seals can become infected by CDV. In some CDV outbreaks including the mass mortalities among Baikal and Caspian seals and large felids in the Serengeti Park, terrestrial carnivores including dogs and wolves have been suspected as vectors for the infectious agent. In addition, lethal infections have been described in non-carnivore species such as peccaries and non-human primates demonstrating the remarkable ability of the pathogen to cross species barriers. Mutations affecting the CDV H protein required for virus attachment to host-cell receptors are associated with virulence and disease emergence in novel host species. The broad and expanding host range of CDV and its maintenance within wildlife reservoir hosts considerably hampers disease eradication.

Potential transmision of dog pathogens to wild carnivores in India

Chaudhary, V. (2016). Threats of Disease Spillover from Domestic Dogs to Wild Carnivores in the Kanha Tiger Reserve, India. MSc disertation  Graduate School of Clemson University.

Many mammalian carnivore species persist in small, isolated populations as a result of habitat destruction, fragmentation, poaching, and human conflict. Their small numbers, limited genetic variability, and increased exposure to domestic animals such as dogs place them at risk of further losses due to infectious diseases. In India, dogs ranging from domestic to feral are associated with villages in and around protected areas, and may serve as reservoirs and vectors of pathogens to the carnivores within. India’s Kanha Tiger Reserve (KTR) is home to a number of threatened and endangered mammalian carnivores including tigers (Panthera tigris), leopards (Panthera pardus), wolves (Canis lupus), and dhole (Cuon alpinus). It also contains hundreds of small villages with associated dog populations, and my goal was to determine whether these dogs pose a disease threat to KTR’s wild carnivores. In the summer of 2014 and again in the winter of 2015 I estimated the density of dogs in villages of varying sizes and distances from KTR’s core zone, and the exposure of these dogs to four pathogens that could threaten wild carnivores: rabies, canine parvovirus (CPV), canine distemper (CDV), and canine adenovirus (CAV). Dog population densities ranged from 3.7 to 23.7/km²(14 to 45 dogs/village), and showed no systematic variation with village area or human population size. These dog populations grew in all villages between the summer of 2014 and winter of 2015, primarily through reproduction. No dog tested positive for rabies but I found high levels of seroprevalence to the other three pathogens: CPV (83.6% in summer 2014,
68.4% in winter 2015), CDV (50.7% in summer 2014, 30.4% in winter 2015) and CAV (41.8% in summer 2014, 30.9% in winter 2015). The declines in seroprevalence between summer and winter were primarily due to births in the population, of animals not exposed to the viruses. I opportunistically documented interactions between the dogs and wild carnivores that might allow disease transmission. I measured these interactions as the presence of wild carnivores in surveyed villages. In this study I document the existence of a large population of unvaccinated dogs in and around KTR, with high levels of seroprevalence to pathogens with broad host ranges. These dogs also have frequent contact with wild carnivores. I conclude that these dogs pose a high risk of disease spillover to wild carnivores in the region.
I also tested for CPV and CDV in wild carnivore samples obtained from the KTR Forest Department from 2010 to 2015. While one tiger blood sample was seropositive for CPV antibodies, the reverse transcriptase polymerase chain reaction found no evidence of CPV in tissue samples from five tigers, one leopard and one palm civet (Paradoxurus hermaphroditus), and no CPV or CDV in the three blood samples of tigers. Despite these results, I argue for continued surveillance in KTR, given the ubiquity of village dogs in the area with high seroprevalence of CDV and CPV and the contact between dogs and endangered carnivores in KTR. 

Fatal canine distemper virus infection of giant pandas in China

Feng, N., Yu, Y., Wang, T., Wilker, P., Wang, J., Li, Y., ... & Xia, X. (2016). Fatal canine distemper virus infection of giant pandas in China. Scientific Reports, 6, 27518.

We report an outbreak of canine distemper virus (CDV) infection among endangered giant pandas (Ailuropoda melanoleuca). Five of six CDV infected giant pandas died. The surviving giant panda was previously vaccinated against CDV. Genomic sequencing of CDV isolated from one of the infected pandas (giant panda/SX/2014) suggests it belongs to the Asia-1 cluster. The hemagglutinin protein of the isolated virus and virus sequenced from lung samples originating from deceased giant pandas all possessed the substitutions V26M, T213A, K281R, S300N, P340Q, and Y549H. The presence of the Y549H substitution is notable as it is found at the signaling lymphocytic activation molecule (SLAM) receptor-binding site and has been implicated in the emergence of highly pathogenic CDV and host switching. These findings demonstrate that giant pandas are susceptible to CDV and suggest that surveillance and vaccination among all captive giant pandas are warranted to support conservation efforts for this endangered species.

First evidence of canine distemper in Brazilian free-ranging felids

Nava, A. F. D., Cullen Jr, L., Sana, D. A., Nardi, M. S., Ramos Filho, J. D., Lima, T. F., ... & Ferreira, F. (2008). First evidence of canine distemper in Brazilian free-ranging felids. Ecohealth, 5(4), 513-518.

Serum samples from 19 jaguars (Panthera onca), nine pumas (Puma concolor), and two ocelots (Leopardus pardalis) were collected between January 1999 and March of 2005 and tested for presence of canine distemper virus (CDV). All cats were free-ranging animals living in two protected areas in the Brazilian Atlantic Forest. In addition, 111 domestic dogs from nearby areas were sampled for CDV. Our results show the first evidence of CDV exposure in Brazilian free-ranging felids. From the 30 samples analyzed, six jaguars and one puma were tested seropositive for CDV. All seropositive large felids were from Ivinhema State Park, resulting in 31.5% of the sampled jaguars or 60% of the total jaguar population in Ivinhema State Park, and 11.28% of the sampled pumas. From the total 111 domestic dogs sampled, 45 were tested seropositive for CDV. At Morro do Diabo State Park, 34.6% of the dogs sampled were positive for CDV, and 100% at Ivinhema State Park. Canine distemper virus in wild felids seems to be related with home range use and in close association with domestic dogs living in nearby areas.

Distemper outbreak and its effect on African wild dog conservation

van de Bildt, M., Kuiken, T., Visee, A. M., Lema, S., Fitzjohn, A. R., & Osterhaus, A. (2002). Distemper outbreak and its effect on African wild dog conservation. Emerging Infectious Diseases (Print),8(2), 211-213.


In December 2000, an infectious disease spread through a captive breeding group of African wild dogs (Lycaon pictus) in Tanzania, killing 49 of 52 animals within 2 months. The causative agent was identified as Canine distemper virus (CDV) by means of histologic examination, virus isolation, reverse transcriptase-polymerase chain reaction analysis, and nucleotide sequencing. This report emphasizes the importance of adequate protection against infectious diseases for the successful outcome of captive breeding programs of endangered species.

Epidemiology, pathology, and genetic analysis of a canine distemper epidemic in Namibia

Gowtage-Sequeira, S., Banyard, A. C., Barrett, T., Buczkowski, H., Funk, S. M., & Cleaveland, S. (2009). Epidemiology, pathology, and genetic analysis of a canine distemper epidemic in Namibia. Journal of wildlife diseases, 45(4), 1008-1020.

Severe population declines have resulted from the spillover of canine distemper virus (CDV) into susceptible wildlife, with both domestic and wild canids being involved in the maintenance and transmission of the virus. This study (March 2001 to October 2003) collated case data, serologic, pathologic, and molecular data to describe the spillover of CDV from domestic dogs (Canis familiaris) to black-backed jackals (Canis mesomelas) during an epidemic on the Namibian coast. Antibody prevalence in jackals peaked at 74.1%, and the clinical signs and histopathologic observations closely resembled those observed in domestic dog cases. Viral RNA was isolated from the brain of a domestic dog from the outbreak area. Sequence data from the phosphoprotein (P) gene and the hemagglutinin (H) genes were used for phylogenetic analyses. The P gene sequence from the domestic dog shared 98% identity with the sequence data available for other CDV isolates of African carnivores. For the H gene, the two sequences available from the outbreak that decimated the lion population in Tanzania in 1994 were the closest match with the Namibian sample, being 94% identical across 1,122 base pairs (bp). Phylogenetic analyses based on this region clustered the Namibian sample with the CDV that is within the morbilliviruses. This is the first description of an epidemic involving black-backed jackals in Namibia, demonstrating that this species has the capacity for rapid and large-scale dissemination of CDV. This work highlights the threat posed to endangered wildlife in Namibia by the spillover of CDV from domestic dog populations. Very few sequence data are currently available for CDV isolates from African carnivores, and this work provides the first sequence data from a Namibian CDV isolate.

Pathogens of wild maned wolves in Brazil

Curi, N. H. D. A., Coelho, C. M., Malta, M. D. C. C., Magni, E. M. V., Sábato, M. A. L., Araújo, A. S., ... & Souza, S. L. P. D. (2012). Pathogens of wild maned wolves (Chrysocyon brachyurus) in Brazil. Journal of wildlife diseases, 48(4), 1052-1056.

The maned wolf, Chrysocyon brachyurus, is an endangered Neotropical canid that survives at low population densities. Diseases are a potential threat for its conservation but to date have been poorly studied. We performed clinical evaluations and investigated the presence of infectious diseases through serology and coprologic tests on maned wolves from Galheiro Natural Private Reserve, Perdizes City, Minas Gerais State, southeastern Brazil. Fifteen wolves were captured between 2003 and 2008. We found high prevalences of antibody to canine distemper virus (CDV; 13/14), canine
parvovirus (CPV; 4/14), canine adenovirus type 2 (13/14), canine coronavirus (5/11), canine parainfluenza virus (5/5), and Toxoplasma gondii (6/8), along with Ancylostomidae eggs in all feces
samples. Antibodies against Leishmania sp. were found in one of 10 maned wolves, and all samples were negative for Neospora caninum. Evidence of high exposure to these viral agents was also observed in unvaccinated domestic dogs from neighboring farms. High prevalence of viral agents and parasites such as CDV, CPV, and Ancylostomidae indicates that this population faces considerable risk of outbreaks and chronic debilitating parasites. This is the first report of exposure to canine parainfluenza virus in Neotropical free-ranging wild canids. Our findings highlight that canine pathogens pose a serious hazard to the viability of maned wolves and other wild carnivore populations in the area and emphasize the need for monitoring and protecting wildlife health in remaining fragments of the Cerrado biome.

Contact between wild and domestic canids and virus transmision

Courtenay, O., Quinnell, R. J., & Chalmers, W. S. K. (2001). Contact rates between wild and domestic canids: no evidence of parvovirus or canine distemper virus in crab-eating foxes. Veterinary Microbiology, 81(1), 9-19.


Evaluating the risk of disease spill-over from domestic dogs to wildlife depends on knowledge of inter-specific contact rates and/or exposure to aetiological agents in dog environments. Here, contact rates of crab-eating foxes (Cerdocyon thous) with sympatric domestic dog populations were measured over 25 months in Amazon Brazil. Foxes and dogs were serologically and clinically monitored for exposure to canine parvovirus (CPV-2) and canine distemper virus (CDV), pathogens known to have caused wildlife population declines elsewhere. Twenty-two of 24 (92%) tagged foxes visited one or more houses in a median 2 (range 1–3) villages per night where dog densities ranged from 7.2 to 15.4 per km² (mean 9.5 per km²). Foxes spent an average 6.4% (0–40.3%) of their 10 h nocturnal activity period in villages, the equivalent of 38 m (range 0–242) per night. The rate of potential exposure to disease agents was thus high, though varied by 3 orders of magnitude for individual foxes. Overall, 46% of the fox population was responsible for 80% of all contacts. None of the 37 monitored foxes however showed serological or clinical evidence of infection with CPV-2 or CDV. Seroprevalences for CPV-2 and CDV antibodies in the local domestic dog population were 13% (3/23) and 9% (2/23), respectively, and 89% of 97 monitored pups born during the study presented clinical signs consistent with active CPV-2 infection (haemorrhagic diarrhoea, vomiting, rapid morbidity and emaciation). Although there was no evidence for infection with either virus in foxes, the high level of contact of foxes with peridomestic habitats suggests that the probability of potential spill-over infections from dogs to foxes is high.

Genetics of CDV in East African carnivores

Carpenter, M. A., Appel, M. J., Roelke-Parker, M. E., Munson, L., Hofer, H., East, M., & O'Brien, S. J. (1998). Genetic characterization of canine distemper virus in Serengeti carnivores. Veterinary immunology and immunopathology, 65(2), 259-266.

The lion (Panthera leo) population in the Serengeti ecosystem was recently afflicted by a fatal epidemic involving neurological disease, encephalitis and pneumonia. The cause was identified as canine distemper virus (CDV). Several other species in the Serengeti were also affected. This report presents CDV H and P gene sequences isolated from Serengeti lions (Panthera leo), spotted hyenas (Crocuta crocuta), bat-eared fox (Otocyon megalotis) and domestic dog (Canis familiaris). Sequence analyses demonstrated that the four Serengeti species carry closely related CDV isolates which are genetically distinct from other CDV isolates from various species and locations. The results are consistent with the conclusions that: (1) a particularly virulent strain of CDV emerged among Serengeti carnivores within the last few years; (2) that strain has recognizable shared-derived (synapomorphic) genetic differences in both H and P genes when compared to CDV from other parts of the world; and (3) that the CDV strain has frequently crossed host species among Serengeti carnivores.

Exposure of free-ranging maned wolves to infectious and parasitic disease agents

Deem, S. L., & Emmons, L. H. (2005). Exposure of free-ranging maned wolves (Chrysocyon brachyurus) to infectious and parasitic disease agents in the Noel Kempff Mercado National Park, Bolivia. Journal of Zoo and Wildlife Medicine, 36(2), 192-197.

Maned wolves (Chrysocyon brachyurus) are neotropic mammals, listed as a CITES Appendix II species, with a distribution south of the Amazon forest from Bolivia, through northern Argentina and Paraguay and into eastern Brazil and northern Uruguay. Primary threats to the survival of free-ranging maned wolves include habitat loss, road kills, and shooting by farmers. An additional threat to the conservation of maned wolves is the risk of morbidity and mortality due to infectious and parasitic diseases. Captive maned wolves are susceptible to, and die from, common infectious diseases of domestic dogs (Canis familiaris) including canine distemper virus (CDV), canine parvovirus (CPV), rabies virus, and canine adenovirus (CAV). Results from this study show that free-ranging maned wolves in a remote area of Bolivia have been exposed to multiple infectious and parasitic agents of domestic carnivores, including CAV, CDV, CPV, canine coronavirus, rabies virus, Leptospira interrogans spp., Toxoplasma gondii, and Dirofilaria immitis, and may be at increased risk for disease due to these agents.

A CDV epidemic in Serengeti

Roelke-Parker, M. E., Munson, L., Packer, C., Kock, R., Cleaveland, S., Carpenter, M., ... & Mwamengele, G. L. (1996). A canine distemper virus epidemic in Serengeti lions (Panthera leo). Nature, 379(6564), 441-445.

CANINE distemper virus (CDV) is thought to have caused several fatal epidemics in canids within the Serengeti–Mara ecosystem of East Africa, affecting silver-backed jackals (Canis mesomelas) and bat-eared foxes (Otocyon megalotis) in 1978 (ref. 1), and African wild dogs (Lycaon pictus) in 1991 (refs 2, 3). The large, closely monitored Serengeti lion population4,5 was not affected in these epidemics. However, an epidemic caused by a morbillivirus closely related to CDV emerged abruptly in the lion population of the Serengeti National Park, Tanzania, in early 1994, resulting in fatal neurological disease characterized by grand mal seizures and myoclonus; the lions that died had encephalitis and pneumonia. Here we report the identification of CDV from these lions, and the close phylogenetic relationship between CDV isolates from lions and domestic dogs. By August 1994, 85% of the Serengeti lion population had anti-CDV antibodies, and the epidemic spread north to lions in the Maasai Mara National reserve, Kenya, and uncounted hyaenas, bat-eared foxes, and leopards were also affected.

Disease and endangered species

Thorne, E., & Williams, E. S. (1988). Disease and endangered species: the black‐footed ferret as a recent example. Conservation Biology, 2(1), 66-74.

Diseases may play major roles in the conservation of endangered species. Although the threat of disease received extensive consideration and influenced research and management activities governing the endangered black-footed ferret (Mustela nigripes) in Wyoming, a canine distemper epizootic in 1985 severely affected a captive breeding program and led to extirpation of the species from the wild. This recent example of the catastrophic effect of epizootic disease in an endangered species is described in an historical context. In addition, examples are given of disease further endangering other rare species, including Mauritius pink pigeon, Père David's deer, cranes, maned wolves, native Hawaiian birak, cheetahs, and others.

__________________

Las enfermedades pueden jugar un papel importante en la conservación de especies en peligro de extinción. Aunque la amenaza de enfermedad recibió gran consideratión e influyó en la investigación y las actividades de manejo del hurón de patas-negras (Mustela nigripes), especie en peligro de extinción en Wyoming en 1985 el moquillo canino epizoótico impactó severamente un programa de crianza en cautiverio y condujo a la extinción de esta especie en su ambiente silvestre. Este reciente ejemplo del efecto catastrófico de una enfermedad epizoótica sobre una especie en peligro de extinción es descrito en un contexto histórico. Además, se dan ejemplos de enfermedades que amenazan aun más a otras especies raras, incluyendo la paloma rosada de Mauricio, el ciervo de David, el lobo de crin, el guepardo, diversas grullas, varias aves de las islas de Hawaii, entre otros.

Canine distemper in endangered Ethiopian wolves

Gordon, C. H., Banyard, A. C., Hussein, A., Laurenson, M. K., Malcolm, J. R., Marino, J., ... & Sillero-Zubiri, C. (2015). Canine distemper in endangered Ethiopian wolves. Emerging infectious diseases, 21(5), 824.

The Ethiopian wolf (Canis simensis) is the world’s rarest canid; ≈500 wolves remain. The largest population is found within the Bale Mountains National Park (BMNP) in southeastern Ethiopia, where conservation efforts have demonstrated the negative effect of rabies virus on wolf populations. We describe previously unreported infections with canine distemper virus (CDV) among these wolves during 2005–2006 and 2010. Death rates ranged from 43% to 68% in affected subpopulations and were higher for subadult than adult wolves (83%–87% vs. 34%–39%). The 2010 CDV outbreak started 20 months after a rabies outbreak, before the population had fully recovered, and led to the eradication of several focal packs in BMNP’s Web Valley. The combined effect of rabies and CDV increases the chance of pack extinction, exacerbating the typically slow recovery of wolf populations, and represents a key extinction threat to populations of this highly endangered carnivore.

Adult and subadult Ethiopian wolf population in Sanetti Plateau, Ethiopia, 2002–2013. Dots indicate wolf population estimates at different time points; arrows indicate canine distemper virus outbreaks in this study.

Density of adult and subadult Ethiopian wolf population in Web Valley, Ethiopia, 2002–2013. Dots indicate wolf population estimates at different time points; arrows indicate known rabies epizootics and canine distemper virus outbreaks in this study. Of 7 wolf packs in Web Valley, 4 went extinct after the 2010 canine distemper virus outbreak; in 2011, two new packs formed in the area.

Model to understand multispecies disease transmition between domestic and wild canids

Belsare, A. V., & Gompper, M. E. (2015). A model-based approach for investigation and mitigation of disease spillover risks to wildlife: Dogs, foxes and canine distemper in central India. Ecological Modelling, 296, 102-112.

Multi-host pathogens can pose a serious conservation threat when free-ranging domestic animal populations occur alongside susceptible populations of wild species. An example is canine distemper virus (CDV), which can occur at high prevalence in domestic dog (Canis familiaris) populations from which it may be transmitted (spillover) into wild carnivore populations. Effective management of such disease threats is hindered by our limited understanding of the the dynamics of interspecific CDV transmission in natural settings. We used a modeling approach to better understand CDV spillover threats to wild Indian foxes (Vulpes bengalensis) occurring in a protected grassland habitat in central India. An agent-based stochastic simulation model was built, and parameterized with data from ecological and epidemiological studies. Based on the sensitivity analyses of the model, the CDV incidence rate in dogs was most influenced by the proportion of roamer dogs in the dog population. The CDV incidence rate in dogs was also sensitive to the CDV introduction frequency in the dog population. The proportion of roamer dogs in the dog population also influenced the number of CDV spillover events. The basic reproductive number (R0) for CDV in the model fox population was 0.85, indicating that CDV could not be independently sustained in the fox population. We used the model to explore potential management strategies to mitigate the risk of CDV spillover. Vaccination of local dog populations was an ineffective disease control strategy, while fox vaccination was highly effective. Interventions potentially resulting in lower contact rates between dogs and foxes, like reduction in village dog density and restricting dog movements in fox habitat, implemented in a sustained and integrated manner would be most effective in mitigating disease threats to foxes. Such modeling approaches can be used to better understand disease threats for other species of management concern, and to contrast potential management interventions.

Dog diseases threat Ethiopian wolf

Laurenson, K., Sillero‐Zubiri, C., Thompson, H., Shiferaw, F., Thirgood, S., & Malcolm, J. (1998). Disease as a threat to endangered species: Ethiopian wolves, domestic dogs and canine pathogens. Animal Conservation, 1(4), 273-280.

With increasing awareness of disease as an endangering process, an assessment of which pathogens might pose a problem and their patterns of infection in natural hosts is necessary. This paper examines the exposure of sympatric Ethiopian wolves (Canis simensis) and domestic dogs to canine distemper virus (CDV), canine adenovirus (CAV) and canine parvovirus (CPV) in the Bale region, Ethiopia and then relates these data to population trends of wolves. Wolves (n= 30) sampled between 1989 and 1992 had been exposed to CDV, CAV and CPV, but only CAV might be able to persist in this wolf population. Anecdotal and serological evidence suggested that an epidemic of CDV occurred in the dog population of the Bale Mountains National Park (BMNP) in 1992–93. All park dogs born since this time were seronegative to CDV, although some young dogs in the nearby urban population were seropositive. Despite evidence of CAV infection in wolves, none of the dogs sampled in the park were CAV seropositive, although this virus appeared highly seroprevalent and endemic in urban dogs. All dogs tested for CPV antibodies were seropositive. The BMNP wolf population declined in the late 1980s and early 1990s, with rabies responsible for a dramatic population reduction between 1990 and 1992. Although the population declined further up until 1995, it is not possible to assess whether the concurrent canine distemper epidemic in park dogs also affected wolves. Nevertheless, with evidence of rabies, CDV, CAV and CPV infections in sympatric domestic dogs and Ethiopian wolves, canid diseases clearly pose a significant threat to the future persistence of this Ethiopian wolf population.

Dog distemper affecting wolfs

Di Sabatino D, Lorusso A, Di Francesco CE, Gentile L, Di Pirro V,  Bellacicco, A.L., Giovannini, A., Di Francesco, G., Marruchella, G., Marsilio, F. & Savini, G. (2014) Arctic Lineage-Canine Distemper Virus as a Cause of Death in Apennine Wolves (Canis lupus) in Italy. PLoS ONE 9(1): e82356. doi:10.1371/journal.pone.0082356

Canine distemper virus (CDV) infection is a primary threat affecting a wide number of carnivore species, including wild animals. In January 2013, two carcasses of Apennine wolves (Canis lupus) were collected in Ortona dei Marsi (L'Aquila province, Italy) by the local Veterinary Services. CDV was immediately identified either by RT-PCR or immunohistochemistry in lung and central nervous tissue samples. At the same time, severe clinical signs consistent with CDV infection were identified and taped (Videos S1–S3) from three wolves rescued in the areas surrounding the National Parks of the Abruzzi region by the Veterinary Services. The samples collected from these symptomatic animals also turned out CDV positive by RT-PCR. So far, 30 carcasses of wolves were screened and CDV was detected in 20 of them. The sequencing of the haemagglutinin gene and subsequent phylogenetic analysis demonstrated that the identified virus belonged to the CDV Arctic lineage. Strains belonging to this lineage are known to circulate in Italy and in Eastern Europe amongst domestic dogs. To the best of our knowledge this is the first report of CDV Arctic lineage epidemics in the wild population in Europe.

Disease impact of dogs

Vanak, A. T., Belsare, A. V. & Gompper, M. E. 2007. Survey of Disease Prevalence in Free-Ranging Domestic Dogs and Possible Spill-Over Risk for Wildlife – A Case Study from the Great Indian Bustard Sanctuary, Maharashtra - India. Final report submitted to the Rufford Small Grants Foundation, UK. Pp 1-13

Domestic dogs are the world’s most common carnivore, and yet the ecology of free-ranging  dogs has rarely been investigated. Many dog populations are subsidized by humans resulting in  high population density, which presumably also have contact rates above the critical threshold  that allows diseases to persist enzootically within the population. Domestic dogs are the  reservoir of infectious diseases that have led to epidemics of rabies, canine distemper and  canine parvovirus in several wild carnivore species, yet little is known about the disease ecology  of domestic dogs in India, and the potential for spill-over risk to wildlife. This project was carried out to assess the disease exposure and health status of free-ranging domestic dogs in the vicinity of a wildlife reserve in central India. We carried out a sero-prevalence survey of canine distemper virus (CDV), canine parvovirus (CPV) and rabies in the dog population surrounding the Great Indian Bustard Sanctuary in Nannaj, Maharashtra. We sampled 74 dogs from four villages surrounding the wildlife reserve and obtained blood samples for testing for IgM and IgG antibodies to CDV and CPV. We also collected salivary swabs from 31 dogs to test for rabies antigen. Antibodies to CPV were detected in 93.3% of the sampled dogs, while 90.7% of dogs had evidence for recent or past exposure to CDV. This suggests that these diseases are enzootic in the dog population, and may pose a significant threat to wild carnivores if disease control measures are not implemented. Rabies was also detected in 2 (6%) of the dogs tested, raising human health concerns as well. We recommend a comprehensive vaccination and dog population control policy as well as an education campaign on responsible dog ownership among villagers.