Detection of Rabies Virus Antibodies in Brazilian Free-Ranging Wild Carnivores

Journal of Wildlife Diseases, 46(4), 2010, pp. 1310–1315 # Wildlife Disease Association 2010

Rodrigo Silva Pinto Jorge,1,2,3,4,8 Monicque Silva Pereira,1 Ronaldo Gonçalves Morato,1,4,5 Karin C. Scheffer,6 Pedro Carnieli, Jr.,6 Fernando Ferreira,2 Mariana Malzoni Furtado,2,7 Cyntia Kayo Kashivakura,7 Leandro Silveira,7 Anah T. A. Jacomo,7 Edson Souza Lima,4 Roge´rio Cunha de Paula,1,5 and Joares Adenı´lson May-Junior2,5 11Centro Nacional de Pesquisa e Conservaç a˜ o de Mamı´ feros Carnı´ voros-CENAP/ ICMBio, Estrada Municipal Hisaichi Takebayashi, 8600, CEP 12952-011, Atibaia-SP, Brazil; 2Departamento de Medicina Veterina´ ria Preventiva e Sau´ de Animal, Faculdade de Medicina Veterina´ ria e Zootecnia, Universidade de Sa˜ o Paulo, av. Prof. Dr. Orlando Marques de Paiva 87, CEP 05508 270, Sa˜ o Paulo-SP, Brazil; 3Instituto Brasileiro de Medicina da Conservaç a˜ o-Trı´ ade, rua Silveira Lobo 32, cx. postal 48, CEP 52061-030, Recife-PE, Brazil; 4Projeto Speothos, rua Pernambuco 179, CEP 78690-000, Nova Xavantina-MT, Brazil; 5Projeto Lobo- Guara´ , Instituto Pro´ -Carnı´ voros, av. Hora´ cio Neto 1030, CEP 12945-010, Atibaia-SP, Brazil; 6Instituto Pasteur de Sa˜ o Paulo, av. Paulista 393, CEP 01311-000, Sa˜ o Paulo-SP, Brazil; 7Jaguar Conservation Fund, cx. postal 193, CEP 75830-000, Mineiros-GO, Brazil; 8Corresponding author (email: [email protected])

ABSTRACT: Rabies virus is a pathogen of major a cycle in these animals that is indepen- concern in free-ranging wild carnivores in dent of the cycle in domestic dogs has several regions of the world, but little is known been reported (Carnieli et al., 2008). In about its circulation in Brazilian wild carnivores. Sera from 211 free-ranging wild carni- that study, the crab-eating fox (Cerdocyon vores, captured from 2000 to 2006 in four thous) was genetically identified as the locations of two Brazilian biomes (Pantanal and main reservoir of Rabies virus among wild Cerrado), were tested for rabies antibodies. canid species in northeastern Brazil. Twenty-six individuals (12.3%) had neutralizing In addition to its relevance for public antibody titers $0.10 IU/ml. The four sampled locations had antibody-positive animals, sug- health, rabies represents a potential threat gesting that Rabies virus circulates in all of to the conservation of free-ranging wild these regions. Results underscore the risk carnivores. This has been demonstrated by posed by rabies for conservation of Brazilian the extensive mortality caused by rabies carnivores and the possibility of the animals outbreaks in isolated populations of the acting as reservoirs for the Rabies virus. Key words: Brazil, conservation, free- most endangered wild canid, the Ethiopi- ranging wild carnivores, public health, rabies, an wolf (Canis simensis; Sillero-Zubiri et serology. al., 1996). The purpose of this study was to assess the exposure to Rabies virus of free- Domestic dogs (Canis familiaris) have ranging wild carnivores in four locations of historically been considered the main two Brazilian biomes, Pantanal and Cer- reservoir species of rabies throughout the rado. world. However, with successful manage- Serum samples were obtained from the ment programs focused on controlling the Biological Samples Bank of the National Rabies virus in dogs, wildlife have over- Research Center for the Conservation of taken domestic animals as the most Natural Predators (CENAP) of the Chico important Rabies virus reservoirs in Eu- Mendes Institute for the Conservation of rope and North America (Smith and Baer, Biodiversity (ICMBio), a Brazilian Gov- 1988; Wandeler, 1988). Similarly, in Latin ernmental agency. Samples were collected America, where efforts to control rabies in from free-ranging wild carnivores cap- humans have been focused on vaccinating tured as part of ecologic studies in four dogs and cats (Felis catus), the sylvatic locations in Pantanal and Cerrado (Fig. 1), cycle, maintained in a wide variety of Brazil, from 2000 to 2006 and stored at mammal hosts, is emerging as a new issue 270 C. Numbers of individuals of each for public health (Bernardi et al., 2005). species captured and locations of capture Free-ranging wild canids have been are specified in Table 1. diagnosed as rabid in the northeastern During immobilization, the physical Brazilian states (Bernardi et al., 2005), and condition and any clinical signs of rabies

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FIGURE 1. Map of Brazil and its biomes. The named locations are sites where free-ranging wild carnivores were captured and tested for antibody to Rabies virus.MG5Minas Gerais; GO5Goias; MT5Mato Grosso; MS5Mato Grosso do Sul. were assessed by clinical examination. microtest (Favoretto et al., 1993) at Seventy-three individuals from Emas Instituto Pasteur (Sa˜o Paulo, Sa˜o Paulo, National Park (ENP) and 24 from Brazil). Animals with neutralizing anti- Serra da Canastra National Park (SCNP) body titers $0.10 IU/ml were considered were fitted with radio collars and moni- positive. Serology was performed on all tored using radiotelemetry. Monitoring samples in 2007. Because results were of individuals was related to the objec- only known after capture and sampling tives of the ecologic studies and not to were complete, it was not possible to objectives of our study. Samples were resample individuals based on serologic tested by simplified fluorescent inhibition results.

TABLE 1. Number of carnivores sampled and tested for the rabies-virus antibody by species and site in Brazil.a

Species ENP SESC Pantanal SCNP Southern Pantanal Total

Cerdocyon thous 26 41 1 — 68 Chrysocyon brachyurus 59 8 24 — 91 Speothos venaticus —1—— 1 Lycalopex vetulus 1—— — 1 Procyon cancrivorus —13— — 13 Panthera onca 2—— 1214 Leopardus pardalis 64—— 10 Puma concolor 17—— 8 Leopardus colocolo 5—— — 5 Total 100 74 25 12 211 a ENP5Emas National Park; SESC5Servic¸o Social do Come´rcio; SCNP5Serra da Canastra National Park. 1312 JOURNAL OF WILDLIFE DISEASES, VOL. 46, NO. 4, OCTOBER 2010

TABLE 2. Carnivores considered positive for exposure to Rabies virus at four locations in Brazil, their date and location of capture, and their neutralizing-antibody titer.

Species Date of capture Locationa Titer (IU/ml)

Chrysocyon brachyurus 15 May 2005 ENP 0.10b Chrysocyon brachyurus 19 August 2004 ENP 0.27b Chrysocyon brachyurus 27 September 2004 ENP 0.10b Chrysocyon brachyurus 13 June 2004 ENP 0.10b Chrysocyon brachyurus 25 March 2004 ENP 0.20b Chrysocyon brachyurus 31 July 2003 ENP 0.10b Chrysocyon brachyurus 18 May 2003 ENP 0.10b Chrysocyon brachyurus 4 May 2003 ENP 0.10b Chrysocyon brachyurus 1 November 2002 ENP 0.13b Chrysocyon brachyurus 23 September 2002 ENP 0.27b Chrysocyon brachyurus 7 July 2001 ENP 0.13b Chrysocyon brachyurus 24 July 2004 SCNP 0.27b Chrysocyon brachyurus 22 November 2005 SCNP 0.13b Cerdocyon thous 25 November 2005 ENP 0.27 Cerdocyon thous 16 July 2006 ENP 0.10 Cerdocyon thous 11 August 2003 Southern Pantanal 0.10 Cerdocyon thous 6 November 2004 SESC Pantanal 0.20 Speothos venaticus 2 August 2006 SESC Pantanal 1.60 Panthera onca 3 December 2005 Southern Pantanal 0.13 Panthera onca 26 February 2006 Southern Pantanal 0.10 Panthera onca 5 June 2006 Southern Pantanal 0.10 Leopardus pardalis 17 April 2002 ENP 0.13b Leopardus pardalis 10 July 2005 ENP 0.10b Puma concolor 20 March 2003 SESC Pantanal 0.10 Leopardus colocolo 3 May 2005 ENP 0.13 Procyon cancrivorus 22 September 2005 SESC Pantanal 0.27 a ENP5Emas National Park; SESC5Servic¸o Social do Come´rcio; SCNP5Serra da Canastra National Park. b Monitored using radiotelemetry.

Among the 211 wild carnivores tested, pampas cats (Leopardus colocolo), and 26 had titers of rabies-neutralizing anti- 7.7% (1/13) for crab-eating raccoons bodies $0.10 IU/ml for a frequency of (Procyon cancrivorus). To our knowledge, 12.3%. Titers and the locations of capture this is the first report of exposure of free- for positive animals are shown in Table 2. ranging maned wolves, bush dogs, jaguars, The frequencies of exposed specimens for ocelots, pumas, and pampas cats to Rabies each region were 16% (16/100) for ENP, virus. 5.4% (4/74) for the Servic¸o Social do None of the positive animals presented Come´rcio (SESC) Pantanal, 8% (2/25) for any clinical signs of rabies. Thirteen SCNP, and 33.3% (4/12) for Southern positive maned wolves from ENP and Pantanal, Brazil. Specimen frequencies for two from SCNP were monitored continu- each exposed species were 14.3% (13/91) ously for periods of 6–51 mo. During that for maned wolves (Chrysocyon brachy- time, no abnormal behaviors, lack of urus), 5.8% (4/69) for crab-eating foxes, muscular coordination, or any typical signs 100% (1/1) for bush dogs (Speothos of rabies were noted. The two positive venaticus), 0% (0/1) for hoary foxes ocelots were monitored for 15 and 24 mo, (Lycalopex vetulus), 23.1% (3/13) for respectively, without any clinical signs of jaguars (Panthera onca), 20% (2/10) for rabies. Similarly, none of the 80 radio- ocelots (Leopardus pardalis), 12.5% (1/8) collared animals that were negative for for pumas (Puma concolor), 20% (1/5) for serology and were monitored for variable SHORT COMMUNICATIONS 1313 periods presented any notable clinical reservoirs. Hence, it is difficult to draw signs of rabies. conclusions about the importance of these Several investigators that have assessed wild cats in the circulation of Rabies virus. exposure of free-ranging wildlife to Rabies This subject deserves more focused study virus used a cutoff of 0.50 UI/ml (Almeida in the future. Nevertheless, our results, et al., 2001; Deem et al., 2004). The World along with the high rabies antibody titer Health Organization (WHO, 1992) rec- found in an oncilla (Leopardus tigrinus)in ommends that cutoff for evaluating human Bolivia (Deem et al., 2004), show that and animal response to vaccination, not rabies may be a threat to the conservation for natural exposure to the virus. Even the of these felids, as well as to other exposed presence of lower levels of detectable South American carnivores, especially antibodies may represent previous natural endangered species. exposure to Rabies virus (Rosatte and The most common transmission route Gunson, 1984). However, we cannot for Rabies virus is through contaminated discard the possibility that the lower levels saliva inoculated through the bite of an of antibody are the result of nonspecific infected animal during the phase of viral inhibition. excretion. Oral infection of carnivores via In this study, the bush dog had the ingestion of contaminated carcasses has highest titer of rabies-neutralizing anti- also been demonstrated (Ramsden and bodies among the tested carnivores. How- Johnston, 1975), but the importance of ever, because only one individual was this route in free-ranging wildlife has sampled, it is difficult to draw conclusions seldom been explored. Although ingestion about the importance of bush dogs for of contaminated carcasses may lead to rabies maintenance in the sylvatic cycle. lethal infection, it is possible that some That individual was captured in a rural animals respond only with the production community. Thus, there is a high likeli- of neutralizing antibodies (Ramsden and hood that exposure originated from do- Johnston, 1975). mestic animals, and there is a risk of A Rabies virus strain adapted to a transmission from the bush dog to humans specific species may be less pathogenic or other domestic animals. Because bush and more immunogenic to phylogeneti- dogs are vulnerable to extinction (IUCN, cally distant species, resulting in a higher 2004), these results have implications for proportion of animals of that species with the conservation of the species. rabies-neutralizing antibodies in the re- Larger numbers of maned wolves and gions where these strains occur (Rosatte crab-eating foxes were sampled, and these and Gunson, 1984). In Brazil, Rabies virus species had a relatively high frequency of isolates associated with vampire bats exposure to the virus, suggesting their (Desmodus rotundus) have been reported potential role as reservoirs for the Rabies in several areas, including the states of virus. Fewer jaguars, pumas, ocelots, Mato Grosso, Mato Grosso do Sul, Goias, pampas cats, crab-eating raccoons, and and Minas Gerais (Ito et al., 2001; hoary foxes were sampled, making it Bernardi et al., 2005), where our samples difficult to make inferences about their were obtained. Therefore, there is consid- role in Rabies virus transmission. How- erable chance that some of the antibody- ever, apart from the hoary fox, all tested positive animals in this study were exposed species had rabies antibody-positive indi- to a vampire bat–related strain of Rabies viduals, suggesting that they had been virus or were exposed via the oral route, exposed to the virus. Although wild canids with a low viral load. and procyonids are known to serve as The Southern Pantanal had the highest Rabies virus reservoirs elsewhere in the proportion of exposed animals (33.3%), world, no wild felids are known to be followed by ENP (16%), SCNP (8%), and 1314 JOURNAL OF WILDLIFE DISEASES, VOL. 46, NO. 4, OCTOBER 2010 the SESC Pantanal (5.3%). Although Maria Luisa S. P. Jorge for suggestions on these results may be a consequence of early versions of this article. higher rates of exposure in the Southern Pantanal and ENP regions, they also may LITERATURE CITED reflect the occurrence of Rabies virus ALMEIDA, M. F., E. MASSAD,E.A.AGUIAR,L.F. strains for which wild carnivores are not MARTORELLI, AND A. M. JOPPERT. 2001. Neutral- natural reservoirs, or they may reflect izing antirabies antibodies in urban terrestrial wildlife in Brazil. Journal of Wildlife Diseases alternative routes of transmission. 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WANDELER, A. I. 1988. Control of wildlife rabies: Report Series 824. World Health Organization, Europe. In Rabies, J. B. Campbell and K. M. Geneva, Switzerland. 84 pp. Charlton (eds.). Kluwer Academic, Norwell, Massachusetts. pp. 365–380. WORLD HEALTH ORGANIZATION (WHO). 1992. Expert Submitted for publication 24 June 2009. Committee on Rabies. Eighth Report. Technical Accepted 13 April 2010.