Rabies vaccination in rural Tanzania

Cleaveland, S., M. Kaare, P. Tiringa, T. Mlengeya & J. Barrat. 2003. A dog rabies vaccination campaign in rural Africa: impact on the incidence of dog rabies and human dog-bite injuries. Vaccine, 21: 1965–1973

Despite the availability of safe and effective rabies vaccines, the incidence of dog rabies has been increasing throughout much of sub-Saharan Africa. Here we describe a vaccination strategy that has resulted in successful control of rabies in a rural dog population of Northwestern Tanzania. From October 1996 to February 2001, four central-point dog vaccination campaigns were conducted in villages within Serengeti District with a mean interval between campaigns of 338, 319 and 456 days. Vaccination coverage of the dog population was estimated from household questionnaires as 64.5, 61.1, 70.6 and 73.7% following each of the four campaigns, respectively. The incidence of dog rabies declined significantly in Serengeti District falling by 70% after the first campaign and by 97% after the second campaign. Over the same period, the incidence of dog rabies did not differ significantly in unvaccinated control villages of Musoma District. The incidence
of human bite injuries from suspected rabid dogs declined significantly in Serengeti District after dog vaccination but not in adjacent unvaccinated districts. Vaccination of 60–70% of dogs has been sufficient to control dog rabies in this area and to significantly reduce demand for human post-exposure rabies treatment. Dog-bite injuries can provide a valuable and accessible source of data for surveillance in countries where case incidence data are difficult to obtain.

Demography of a common urban bird

Balogh, A.L., T.B. Ryder & P. P. Marra. 2011. Population demography of Gray Catbirds in the suburban matrix: sources, sinks and domestic cats. Journal of Ornithology, DOI 10.1007/s10336-011-0648-7

Understanding factors that limit the productivity and survival of birds in rapidly changing human-dominated landscapes are key to managing future population persistence. To date, few studies have quantified both nest
success and post-fledging survival for birds breeding within the suburban matrix. Here, we estimated nest success and juvenile post-fledging survival for Gray Catbirds (Dumetella carolinensis) and used those site-specific parameters to model source–sink dynamics at three sites in suburban Washington DC (USA). Cumulative nest success probability varied substantially among suburban sites and indicated that in some cases suburban habitats may provide suitable breeding sites for passerine birds. In addition, we documented the effects of sex and brood size on post-fledging survival rates and determined the role of predation on dispersing fledglings. Like nest success, estimates of post-fledging juvenile survival also varied among sites and highlight the importance of site-specific demographic estimates in urban habitats. Predation accounted for 79% of all mortalities, with 47% of known predation events attributable to domestic cats (Felis catus). Our models of source–sink dynamics underscore the importance of seasonal recruitment parameters for calculating population growth rate and subsequent persistence. This study provides parameter estimates for two critical life history stages in the avian annual cycle in the suburban matrix and posits that predation drives differential nest and post-fledging survival within human-dominated environments.

Rabies in India

M.K. Sudarshan, S.N. Madhusudana, B.J. Mahendra, N.S.N. Rao, D.H. Ashwath Narayana, S. Abdul Rahman, F.-X. Meslin, D. Lobo, K. Ravikumar & Gangaboraiah. 2007. Assessing the burden of human rabies in India: results of a national multi-center epidemiological survey. International Journal of Infectious Diseases, 11, 29—35


Objective: Human rabies has been endemic in India since time immemorial, and the true incidence of the disease and nationwide epidemiological factors have never been studied. The main objectives of the present study were to estimate the annual incidence of human rabies in India based on a community survey and to describe its salient epidemiological features.
Methods: The Association for Prevention and Control of Rabies in India (APCRI) conducted a national multi-center survey with the help of 21 medical schools during the period February-August 2003. This community-based survey covered a representative population of 10.8 million in mainland India. Hospital-based data were also obtained from the 22 infectious diseases hospitals.
A separate survey of the islands of Andaman, Nicobar, and Lakshadweep, reported to be free from rabies, was also undertaken.
Results: The annual incidence of human rabies was estimated to be 17 137 (95% CI 14 109-20 165). Based on expert group advice, an additional 20% was added to this to include paralytic/atypical forms of rabies, providing an estimate of 20 565 or about 2 per 100 000 population. The majority of the victims were male, adult, from rural areas, and unvaccinated. The main animals responsible for bites were dogs (96.2%), most of which were stray. The most common bite sites were the extremities. The disease incubation period ranged from two weeks to six months.

Rabies in Tanzania / Rabia en Tanzania

Cleaveland,S., E.M. Fèvre, M. Kaare & P.G. Coleman. 2002. Estimating human rabies mortality in the United Republic of Tanzania from dog bite injuries. Bulletin of the World Health Organization, 80: 304-310.


Objective: To make quantitative predictions about the magnitude of underreporting of human rabies deaths in the United Republic of Tanzania.
Methods: Human rabies deaths were estimated by using a series of probability steps to calculate the likelihood of rabies developing
after the bite of a suspected rabid dog, incorporating field data on the incidence of animal bite injuries, the accuracy of rabies
recognition, the distribution of bite wounds, and post-exposure treatment.
Findings: Predicted human rabies mortality was estimated to be (a) 1499 deaths per year (95% confidence interval 891–2238),
equivalent to an annual incidence of 4.9 (2.9–7.2) deaths/100 000, when active surveillance data on bite incidence were used, and
(b) 193 deaths per year (32–409), corresponding to an annual incidence of 0.62 (0.1–1.32) deaths/100 000, when national bite
statistics were used. The annual mean number of rabies deaths officially recorded for the same period was 10.8 (7.7–14.0).
Conclusion: In the United Republic of Tanzania, cases of rabies in humans have been greatly underreported. Dog bite injuries are an accessible source of epidemiological data that may be used to estimate the public health burden of rabies and to monitor epidemiological trends in developing countries.

Estimación de la mortalidad por rabia humana causada por mordeduras de perro en la República Unida de Tanzanıa.

Objetivo: Hacer predicciones cuantitativas sobre la magnitud de la subnotificación de las defunciones por rabia humana en la República Unida de Tanzania.
Métodos: Se estimó la mortalidad por rabia humana usando una serie de pasos probabilísticos para calcular el riesgo de desarrollar rabia tras la mordedura de un perro presuntamente rabioso; a ese fin, se incorporaron datos de campo sobre la incidencia de mordeduras, la precisión del diagnóstico de la rabia, la distribución de las mordeduras y el tratamiento posterior a la exposición.
Resultados: Según las predicciones efectuadas, usando los datos aportados por la vigilancia activa de las mordeduras la mortalidad ascendía a (a) 1499 defunciones al año (intervalo de confianza (IC) 95%: 891–2238), lo que equivale a una incidencia anual de 4,9 (2,9–7,2) defunciones/100 000; al emplear las estadísticas nacionales sobre mordeduras, en cambio, se obtenían 193 defunciones anuales (32–409), lo que se traduce en una incidencia anual de 0,62 (0,1–1,32) defunciones /100 000. La media anual oficial para el mismo periodo fue de 10,8 (7,7–14,0) muertes por rabia.
Conclusión: En la República Unida de Tanzania, la notificación de los casos de rabia humana ha estado muy por debajo de las cifras reales. La información sobre las lesiones por mordedura de perro es una fuente accesible de datos epidemiológicos que pueden utilizarse para estimar la carga de salud pública que supone la rabia y para vigilar las tendencias epidemiológicas en los países en desarrollo.

Cat hybridisation in UK

Beaumont, M. E.M. Barratt, D.Gottelli, A.C. Kitchener, M.J. Daniels, J.K. Pritchard & M.W. Bruford. 2001. Genetic diversity and introgression in the Scottish wildcat. Molecular Ecology, 10, 319–336

This paper describes a genetic analysis of wild-living cats in Scotland. Samples from 230 wild-living Scottish cats (including 13 museum skins) and 74 house cats from England and Scotland were surveyed for nine microsatellite loci. Pelage characteristics of the wild-living cats were recorded, and the cats were then grouped into five separate categories depending on the degree to which they conformed to the characteristics attributed to Felis silvestris Schreber, 1775. Allele frequency differences between the morphological groups are greater than those among the three house cat samples. Analysis of genetic distances suggests that more of the differences between individuals can be explained by pelage than geographical proximity, and that pelage and geographical location are not confounded. Ordination of the genetic distances suggests two main groups of wild-living cats, with intermediates, and one group is genetically very similar to the house cats, while the other group contains all cats taxonomically identified as wildcat based on morphology. A genetic mixture analysis gives similar results to the ordination, but also suggests that the genotypes of a substantial number of cats in the wildcat group are drawn from a gene pool with genotypes in approximately equilibrium proportions. We argue that this is evidence that these cats do not have very recent domestic ancestry. However, from the morphological data it is highly likely that this gene pool also contains a contribution from earlier introgression of domestic cat genes.


See more on domestic cat introgression in wildcat

Wolf-dog hybrid in Scandinavia

Vilà, C., C. Walker, A.-K. Sundqvist, Ø Flagstad, Z. Andersone, A. Casulli, I. Kojola, H. Valdmann, J. Halverson & H. Ellegren. 2003. Combined use of maternal, paternal and bi-parental genetic markers for the identification of wolf–dog hybrids. Heredity, 90, 17–24

The identification of hybrids is often a subject of primary concern for the development of conservation and management strategies, but can be difficult when the hybridizing species are closely related and do not possess diagnostic genetic markers. However, the combined use of mitochondrial DNA (mtDNA), autosomal and Y chromosome genetic markers may allow the identification of hybrids and of the direction of hybridization. We used these three types of markers to genetically characterize one possible wolf–dog hybrid in the endangered Scandinavian wolf population. We first characterized the variability of mtDNA and Y chromosome markers in Scandinavian wolves as well as in neighboring wolf populations and in dogs. While the mtDNA data suggested that the target sample could correspond to a wolf, its Y chromosome type had not been observed before in Scandinavian wolves. We compared the genotype of the target sample at 18 autosomal microsatellite markers with those expected in pure specimens and in hybrids using assignment tests. The combined results led to the conclusion that the animal was a hybrid between a Scandinavian female wolf and a male dog. This finding confirms that inter-specific hybridization between wolves and dogs can occur in natural wolf populations. A possible correlation between hybridization and wolf population density and disturbance deserves further research.

See more about wild canid hybridisation with dogs

Gene introgression between dogs and wolves

Verardi A, Lucchini V & Randi E. 2006. Detecting introgressive hybridization between free-ranging domestic dogs and wild wolves (Canis lupus) by admixture linkage disequilibrium analysis. Molecular Ecology, 15 (10):2845-2855.

Occasional crossbreeding between free-ranging domestic dogs and wild wolves (Canis lupus) has been detected in some European countries by mitochondrial DNA sequencing and genotyping unlinked microsatellite loci. Maternal and unlinked genomic markers, however, might underestimate the extent of introgressive hybridization, and their impacts on the preservation of wild wolf gene pools. In this study, we genotyped 220 presumed Italian wolves, 85 dogs and 7 known hybrids at 16 microsatellites belonging to four different linkage groups (plus four unlinked microsatellites). Population clustering and individual assignments were performed using a Bayesian procedure implemented in structure 2.1, which models the gametic disequilibrium arising between linked loci during admixtures, aiming to trace hybridization events further back in time and infer the population of origin of chromosomal blocks. Results indicate that (i) linkage disequilibrium was higher in wolves than in dogs; (ii) 11 out of 220 wolves (5.0%) were likely admixed, a proportion that is significantly higher than one admixed genotype in 107 wolves found previously in a study using unlinked markers; (iii) posterior maximum-likelihood estimates of the recombination parameter r revealed that introgression in Italian wolves is not recent, but could have continued for the last 70 (+/- 20) generations, corresponding to approximately 140-210 years. Bayesian clustering showed that, despite some admixture, wolf and dog gene pools remain sharply distinct (the average proportions of membership to wolf and dog clusters were Q(w) = 0.95 and Q(d) = 0.98, respectively), suggesting that hybridization was not frequent, and that introgression in nature is counteracted by behavioural or selective constraints.

See more about wild canid hybridisation with dogs

Hybridisation dog/wolf

Randi, E., V. Lucchini, M.F. Christensen, N. Mucci, S.M. Funk, G. Dolf & V. Loeschcke. 2000. Mitochondrial DNA Variability in Italian and East European Wolves: Detecting the consequences of Small Population Size and Hybridization. Conservation Biology, 14 (2): 464-473

The Italian wolf (Canis lupus) population has declined continuously over the last few centuries and become isolated as a result of the extermination of other populations in central Europe and the Alps during the nineteenth century. In the 1970s, approximately 100 wolves survived in 10 isolated areas in the central and southern Italian Apennines. Loss of genetic variability, as suggested by preliminary studies of mitochondrial DNA (mtDNA) sequences, hybridization with feral dogs, and the illegal release of captive, non-native wolves are considered potential threats to the viability of the Italian wolf population. We sequenced 546 base pairs of the mtDNA control region in a comprehensive set of Italian wolves and compared them to those of dogs and other wolf populations from Europe and the Near East. Our data confirm the absence of mtDNA variability in Italian wolves: all 101 individuals sampled across their distribution in Italy had the same, unique haplotype, whereas seven haplotypes were found in only 26 wolves from an outbred population in Bulgaria. Most haplotypes were specific either to wolves or dogs, but some east European wolves shared haplotypes with dogs, indicative of hybridization. In contrast, neither hybridization with dogs nor introgression of non-native wolves was detected in the Italian population. These findings exclude the introgression of dog genes via matings between male wolves and female dogs, the most likely direction of hybridization. The observed mtDNA monomorphism is the possible outcome of random drift in the declining and isolated Italian wolf population, which probably existed at low effective population size during the last 100–150 years. Low effective population size and the continued loss of genetic variability might be a major threat to the long-term viability of Italian wolves. A controlled demographic increase, leading to recolonization of the historical wolf range in Italy, should be enforced.


La población del lobo Italiano (Canis lupus) ha disminuido continuamente a lo largo de los últimos siglos y se ha aislado como resultado de la exterminación de otras poblaciones en Europa central y los Alpes durante el siglo diecinueve. En los años 70, aproximadamente 100 lobos sobrevivieron en 10 áreas aisladas de los Apeninos centrales y del sur. La pérdida de variabilidad genética, como lo han sugerido estudios preliminares de secuencias de ADN mitocondrial (ADNmt), la hibridización con perros silvestres, y la liberación ilegal de lobos cautivos no nativos son consideradas amenazas potenciales para la viabilidad de las poblaciones italianas de lobos. Secuenciamos 546 pares de bases de la región control del ADNmt en un grupo amplio de lobos italianos y los comparamos con perros y otras poblaciones de lobos de Europa y del Cercano Oriente. Nuestros datos confirman la ausencia de variabilidad en el ADNmt en los lobos italianos: Los 101 individuos muestreados a lo largo de su distribución en Italia tuvieron el mismo haplotipo único, mientras que se encontraron siete haplotipos en tan solo 26 lobos de la población de Bulgaria. La mayoría de los haplotipos fueron específicos a los lobos o a los perros, pero algunos lobos del este de Europa compartieron haplotipos con los perros, indicando hibridización. En contraste, ni la hibridización con perros, ni la introgresión de lobos no nativos fue detectada en la población italiana. Estos resultados excluyen la introgresión de genes de perros mediante cruzas entre lobos machos y hembras de perros, la dirección más probable de hibridización. El monomorfismo de ADNmt observado es el posible resultado de la deriva génica en el declive de la población aislada del lobo italiano, la cual probablemente ha existido en un tamaño poblacional efectivo bajo durante por lo menos los últimos 100–150 años. El bajo tamaño poblacional efectivo y la continua pérdida de variabilidad genética podría ser una mayor amenaza para la viabilidad a largo plazo del lobo italiano. Un incremento demográfico controlado, que conduzca hacia la recolonización del rango histórico del lobo en Italia, debería ser puesto en ejecución.


See more about wild canid hybridisation with dogs

Disturbance from dogs or from people?

Reed, S. & A.D. Merenlender. 2011. Effects of Management of Domestic Dogs and Recreation on Carnivores in Protected Areas in Northern California. Conservation Biology, 25(3):504-513

In developed countries dogs (Canis lupus familiaris) are permitted to accompany human visitors to many protected areas (e.g., >96% of protected lands in California, U.S.A.), and protected-area management often focuses on regulating dogs due to concerns about predation, competition, or transmission of disease and conflicts with human visitors. In 2004 and 2005, we investigated whether carnivore species richness and abundance were associated with management of domestic dogs and recreational visitation in protected areas in northern California. We surveyed for mammalian carnivores and human visitors in 21 recreation areas in which dogs were allowed offleash or onleash or were excluded, and we compared our observations in the recreation areas with observations in seven reference sites that were not open to the public. Carnivore abundance and species richness did not differ among the three types of recreation areas, but native carnivore species richness was 1.7 times greater (p < 0.01) and the relative abundances of native coyotes (Canis latrans) and bobcats ( Lynx rufus) were over four times greater (p < 0.01) in the reference sites. Abundances of bobcats and all carnivores declined as the number of visitors increased. The policy on domestic dogs did not appear to affect species richness and abundance of mammalian carnivores. But the number of dogs we observed was strongly associated with human visitation (R²= 0.54), so the key factors associated with recreational effects on carnivores appear to be the presence and number of human visitors to protected areas.

Dogs displacing birds

Banks, P.B. & J. V Bryant. 2007. Four-legged friend or foe? Dog walking displaces native birds from natural areas. Biology Letters, 3 (6): 611-613

Dog walking is among the world's most popular recreational activities, attracting millions of people to natural areas each year with diverse benefits to human and canine health. But conservation managers often ban dog walking from natural areas fearing that wildlife will see dogs as potential predators and abandon their natural habitats, resulting in outcry at the restricted access to public land. Arguments are passionate on both sides and debate has remained subjective and unresolved because experimental evidence of the ecological impacts of dog walking has been lacking. Here we show that dog walking in woodland leads to a 35% reduction in bird diversity and 41% reduction in abundance, both in areas where dog walking is common and where dogs are prohibited. These results argue against access by dog walkers to sensitive conservation areas.

Dogs affecting distribution of threatened ungulates

Silva-Rodriguez, E.A. & K.E. Sieving. 2012. Domestic dogs shape the landscape-scale distribution of a threatened forest ungulate. Biological Conservation, 150: 103-110

Domestic dogs are the most abundant carnivores worldwide, primarily due to human support. Food and other subsidies to dogs do not necessarily prevent dog predation on wildlife, particularly where dogs are allowed to range freely. Dog impacts on wildlife are suspected to be significant, yet the nature of dog– wildlife interactions is not fully understood. We tested the hypothesis that the distribution of dogs can significantly influence the space use of potential prey, and that both lethal and non-lethal mechanisms may underlie this interaction. If this is true, then we predicted that (1) evidence of predation and harassment by dogs should be evident where prey and dog activities overlap and (2) potential prey should be less frequent in areas where the probability of dog presence is high. To test these predictions we conducted two related studies. (1) We interviewed dog owners to estimate the probability of dog attack on pudu (Pudu puda), a globally vulnerable deer, and the lethality of these attacks. (2) We conducted a camera-trap survey documenting the landscape-scale distribution of pudu and dogs. Interviews showed that both the probability of dog attack on pudu (>85%) and the lethality of such attacks was high (50%). In occupancy models applied to the camera-trap data, the variable that best explained the distribution of pudus was the probability of dog presence. We tested three alternative explanations for the negative association between pudus and dogs that were not supported. Our findings suggest that dogs are efficient at chasing pudu they detect and that both predation and non-lethal (avoidance) consequences of harassment may be shaping the distribution of pudu. This work brings into focus important mechanisms underlying the threats of domestic dogs to endangered prey.

Frigatebird returns to nest on Ascension for first time since Darwin

Endangered species may be saved from extinction after eradication of feral cats that had been eating its chicks
Robin McKie, science editor The Observer Saturday 8th December

One of the world's rarest seabirds has returned to remote Ascension Island in the Atlantic 150 years after its colony was wiped out by feral cats. Last week ornithologists spotted two nests containing eggs being guarded by Ascension frigatebirds, the first of the species to breed there since Charles Darwin visited the island in the early 19th century.

Ascension frigatebirds only survived in a small colony on a nearby rocky outcrop where they were considered to be highly vulnerable to outbreaks of disease and oil spills. But now they have returned to the island after which they are named, raising hopes that the vulnerable bird may be rescued from extinction.

The news marks the success of a project which has cost UK taxpayers more than £500,000 and has involved the eradication of hundreds of feral cats that had been eating frigatebird chicks.

"We are absolutely overwhelmed," said Derren Fox, a conservation officer based on Ascension. "We thought it would take decades for the Ascension frigate to come back and breed after we had got rid of the island's feral cats. But we have already succeeded after only a few years. This suggests we have a real chance of saving the Ascension frigate."

The project's success also raises hopes of saving colonies of other species threatened by feral animals. These include populations of seabirds and amphibians on Montserrat, Gough Island and South Georgia, which are all ravaged by rats, mice and other wild creatures.

In the early 19th century, Ascension Island was home to more than 20 million seabirds, mainly masked boobies, black noddies, brown noddies and Ascension frigatebirds. The frigatebird was considered to be the most important because it was unique to the island. Adults are about 30 inches in length while males have distinctive red sacs on their chests which they inflate during courtship.

Around 1800, rats – accidently introduced by settlers – began to kill off chicks. Cats were imported to kill the rats but instead joined in the killing of frigatebird chicks. "By the time Darwin visited the island in 1836, there were only a few frigatebirds left and the last few were killed off not long after he left," said Clare Stringer of the RSPB, which has played a key role in re-establishing the bird on Ascension. Only a small colony of around 10,000 survived on Boatswain Bird Island, a rocky outcrop off Ascension's east coast which could not be reached by cats.

In 2002, the RSPB – backed with funding from the Foreign Office – launched a programme to eradicate Ascension's feral cats. "It was slightly tricky," said Stringer. "We had to avoid killing islanders' pet cats and kill only feral animals. Owners were told to collar and microchip their pets. Then traps were laid and feral cats caught in these were put down."

In 2006, Ascension was declared to be free of wild cats. "It has taken six years to get frigatebirds to start to recolonise the island since we got rid of the feral cats and frankly it could have taken much longer," said Fox, who – with fellow conservation officer Stedson Stroud – has been monitoring the island for signs of the frigatebird's return. "We now have two nests being tended by parent birds and that should encourage a lot more to settle here in future."

http://www.guardian.co.uk/environment/2012/dec/08/frigatebird-returns-to-ascension

Iberian lynx naïf to domestic carnivores pathogens

Roelke ME, Johnson WE, Millán J, Palomares F, Revilla E, Rodríguez A, Calzada J, Ferreras P, León-Vizcaíno, Delibes M & O’Brien SJ. 2008. Exposure to disease agents in endangered Iberian lynx (Lynx pardinus). European Journal of Wildlife Research, 54: 171-178

The Iberian lynx (Lynx pardinus) is the most endangered felid species in the world. Lynx populations have decreased dramatically in size and distribution in the last four decades, thus becoming increasingly vulnerable to catastrophic events such as epizooties. From 1989 to 2000, serum samples were obtained from 48 free-ranging lynx captured in the Doñana National Park (DNP, n = 31) and mountains of Sierra Morena (SM, n = 17) in southern Spain. Samples were tested for antibodies against Toxoplasma gondii, feline herpesvirus 1 (FHV-1), feline calicivirus (FCV), feline/canine parvovirus (FPV/CPV), feline coronavirus, feline immunodeficiency virus (FIV), feline leukaemia virus and canine distemper virus (CDV) and for FeLV p27 antigen, to document baseline exposure levels. Antibodies against T. gondii were detected in 44% of lynx, with a significantly greater prevalence in DNP (61%) than in SM (12%). In DNP, prevalence was significantly higher in adult (81%) than in juvenile and sub-adult (41%) lynx, but no such difference was observed in SM. Low prevalences (≤11%) of minimally positive titres were found for FHV-1, FCV and FPV/CPV. This, combined with the lack of evidence for exposure to CDV, FIV and FeLV, suggests that these lynx populations are naïve and might be vulnerable to a disease outbreak in the future. Because of the reduced size of lynx populations, the documented low level of genetic variation (particularly in the DNP population) coupled with the recently documented state of immune depletion in a majority of necropsied lynx, it is important to better understand the threat and potential impact that disease agents might pose for the conservation of this endangered species. Future surveillance programs must include possible disease reservoir hosts such as domestic cats and dogs and other wild carnivores.

Pathogens on Iberian lynx

Millán J, Candela MG, Palomares F, Cubero MJ, Rodríguez A, Barral M, de la Fuente J, Almería S & Vizcaíno LL. 2009. Disease threats to the endangered Iberian lynx (Lynx pardinus). The Veterinary Journal, 182: 114-124

The Iberian lynx, (Lynx pardinus), is the most endangered felid in the world. To determine whether sympatric carnivores are reservoirs of pathogens posing a disease risk for the lynx, evidence of exposure to 17 viral, bacterial and protozoan agents was investigated in 176 carnivores comprising 26 free-living lynx, 53 domestic cats, 28 dogs, 33 red foxes (Vulpes vulpes), 24 Egyptian mongooses (Herpestes ichneumon), 10 common genets (Genetta genetta) and 2 Eurasian badgers (Meles meles) in the areas inhabited by the last two populations of Iberian lynx, both in Andalusia (South-Western Spain).

The results indicated that the lynx had low rates of contact with viral pathogens, with one seropositive finding each for feline leukemia virus, parvovirus and canine adenovirus-1, whereas contact with bacteria and protozoa appeared more frequent. Active infections with parvovirus, Ehrlichia spp., Mycobacterium bovis,Leptospira interrogans and Cytauxzoon spp. were confirmed. In contrast, 53% of the domestic cats were exposed to some infectious agent (prevalence range 4.5–11.4%). Antibodies to canine distemper virus and parvovirus were frequently found in dogs (32% and 42%, respectively) and foxes (30% and 12%). Past or present infections with parvovirus, Ehrlichia spp., Chlamydophila spp., M. bovis, Salmonella enterica, L. interrogans, Toxoplasma gondii, and Neospora caninum were also detected in these and other species surveyed.

Questionnaires to owners revealed that 14% of the dogs but none of the cats had been vaccinated, and no cat had been neutered. Based on the apparent absence of acquired immunity of the lynx against infectious agents, the frequent detection of agents among sympatric carnivores, and the reported lack of immunocompetence of the Iberian lynx, a disease outbreak among the local abundant carnivores may pose a serious disease risk for lynx conservation.

FeLV on Iberian lynx

Meli M.L., Cattori V., Martínez F., López G., Vargas A., Palomares F., López-Bao J.V., Hofmann-Lehmann R. & Lutz H. 2010. Feline Leukemia virus infection: A threat for the survival of the critically endangered Iberian lynx (Lynx pardinus): Veterinary Immunology and Immunopathology, 134: 61-67

The Iberian lynx (Lynx pardinus) is considered the most endangered felid species in the world. To date, less than 200 animals remain in the wild. Low numbers and genetic uniformity may contribute to render this species particularly susceptible to infectious diseases. Different pathogens have been identified in Iberian lynxes; including several feline bacterial and viral agents. Within a 6-month period starting in December 2006, 12 lynxes living in the northern part of the Doñana area were found to be infected with feline leukemia virus (FeLV). Eleven of these animals were antigenemic, and four of them died in the wild in less than 6 months since the first infected animal had been discovered. The remaining viremic lynxes were captured and allocated to a quarantine center to stop the spread of the infection. An additional three animals died shortly in the quarantine center due to acute anemic disease. Sequencing of the envelope surface unit gene revealed a common origin for the FeLV found in all lynxes. The sequences were closely related to FeLV-A/61E, originally isolated from cats in the USA. Our data demonstrate that, similarly to FeLV, the introduction of a new or particularly pathogenic infection brought into the small population of Iberian lynxes by other wild carnivores or feral cats and dogs roaming in the same habitats have severe consequences. It could result in epidemics that have the potential to eradicate the entire lynx population