Interspecies transmission of feline immunodeficiency virus from the domestic cat to the Tsushima cat (Felis bengalensis euptilura) in the wild

Clinico-epidemiological survey of feline parvovirus circulating in three Egyptian provinces from 2020 to 2021

Feline parvovirus infection, caused by feline parvovirus and canine parvovirus 2, is a highly contagious, life-threatening disease affecting cats. The available epidemiological data on parvovirus infection in cats in Egypt is limited. Therefore, the aim of the current study was to provide data concerning the epidemiological profile of cats infected with parvovirus, including the prevalence of parvovirus infection in cats in three Egyptian provinces (Sohag, Assiut, and Cairo) and the associated risk factors. Using rapid antigen tests of fecal samples and conventional PCR, the overall prevalence of parvovirus infection in cats was found to be 35% (35/100) and 43% (43/100), respectively. Anorexia, bloody diarrhea, severe dehydration, hypothermia, and vomiting were the most common clinical findings significantly associated with parvovirus-infected cats. The geographical location (Sohag) and the season (winter) were both statistically significant risk factors for parvovirus infection. These findings indicate that parvoviruses are circulating in different regions of Egypt. Our study provides baseline epidemiological data for future preventive and control measures against parvovirus infection, as well as highlighting the need for future genomic surveillance studies involving a large study population from various parts of Egypt in order to better shape the epidemiological picture of parvovirus infection.

Feline Foamy Virus Transmission in Tsushima Leopard Cats (Prionailurus bengalensis euptilurus) on Tsushima Island, Japan

Tsushima leopard cats (TLC; Prionailurus bengalensis euptilurus) only inhabit Tsushima Island, Nagasaki, Japan and are critically endangered and threatened by infectious diseases. The feline foamy virus (FFV) is widely endemic in domestic cats. Therefore, its transmission from domestic cats to TLCs may threaten the TLC population. Thus, this study aimed to assess the possibility that domestic cats could transmit FFV to TLCs. Eighty-nine TLC samples were screened, and FFV was identified in seven (7.86%). To assess the FFV infection status of domestic cats, 199 domestic cats were screened; 14.07% were infected. The phylogenetic analysis revealed that the FFV partial sequence from domestic cats and TLC sequences clustered in one clade, suggesting that the two populations share the same strain. The statistical data minimally supported the association between increased infection rate and sex (p = 0.28), indicating that FFV transmission is not sex dependent. In domestic cats, a significant difference was observed in FFV detection in feline immunodeficiency virus (p = 0.002) and gammaherpesvirus1 infection statuses (p = 0.0001) but not in feline leukemia virus infection status (p = 0.21). Monitoring FFV infection in domestic cats and TLC populations is highly recommended as part of TLC surveillance and management strategies.

Increased Risk of Infection with Severe Fever with Thrombocytopenia Virus among Animal Populations on Tsushima Island, Japan, Including an Endangered Species, Tsushima Leopard Cats

To investigate the seroprevalence of severe fever with thrombocytopenia syndrome (SFTS) among wild and companion animals on Tsushima Island, Japan, SFTS virus (SFTSV)-specific ELISA and virus-neutralizing tests were conducted on 50 wild boars, 71 Sika deer, 84 dogs, 323 domestic cats, and 6 Tsushima leopard cats. In total, 1 wild boar (1.8%), 2 dogs (2.4%), 7 domestic cats (2.2%), and 1 Tsushima leopard cat (16.7%) were positive for anti-SFTSV antibodies. Among the 11 positive animals, 10 were collected after 2019, and all were found on the southern part of the island. SFTSV, thus far, seems to be circulating within a limited area of Tsushima Island. To protect humans and animals, including endangered Tsushima leopard cats, from SFTSV infection, countermeasures are needed to prevent the spread of SFTSV on Tsushima Island.

Management of Suspected Cases of Feline Immunodeficiency Virus Infection in Eurasian Lynx (Lynx lynx) During an International Translocation Program

The Eurasian lynx (Lynx lynx) population in Switzerland serves as a source for reintroductions in neighboring countries. In 2016–2017, three lynx from the same geographical area were found seropositive for feline immunodeficiency virus (FIV) in the framework of an international translocation program. This novel finding raised questions about the virus origin and pathogenicity to lynx, the emerging character of the infection, and the interpretation of serological results in other lynx caught for translocation. Archived serum samples from 84 lynx captured in 2001–2016 were retrospectively tested for FIV antibodies by Western blot. All archived samples were FIV-negative. The three seropositive lynx were monitored in quarantine enclosures prior to euthanasia and necropsy. They showed disease signs, pathological findings, and occurrence of co-infections reminding of those described in FIV-infected domestic cats. All attempts to isolate and characterize the virus failed but serological data and spatiotemporal proximity of the cases suggested emergence of a lentivirus with antigenic and pathogenic similarities to FIV in the Swiss lynx population. A decision scheme was developed to minimize potential health risks posed by FIV infection, both in the recipient and source lynx populations, considering conservation goals, animal welfare, and the limited action range resulting from local human conflicts. Development and implementation of a cautious decision scheme was particularly challenging because FIV pathogenic potential in lynx was unclear, negative FIV serological results obtained within the first weeks after infection are unpredictable, and neither euthanasia nor repatriation of multiple lynx was acceptable options. The proposed scheme distinguished between three scenarios: release at the capture site, translocation, or euthanasia. Until April 2021, none of the 40 lynx newly captured in Switzerland tested FIV-seropositive. Altogether, seropositivity to FIV was documented in none of 124 lynx tested at their first capture, but three of them seroconverted in 2016–2017. Diagnosis of FIV infection in the three seropositive lynx remains uncertain, but clinical observations and pathological findings confirmed that euthanasia was appropriate. Our experiences underline the necessity to include FIV in pathogen screenings of free-ranging European wild felids, the importance of lynx health monitoring, and the usefulness of health protocols in wildlife translocation.

Cross-species transmission of retroviruses among domestic and wild felids in human-occupied landscapes in Chile

Human transformation of natural habitats facilitates pathogen transmission between domestic and wild species. The guigna (Leopardus guigna), a small felid found in Chile, has experienced habitat loss and an increased probability of contact with domestic cats. Here, we describe the interspecific transmission of feline leukemia virus (FeLV) and feline immunodeficiency virus (FIV) between domestic cats and guignas and assess its correlation with human landscape perturbation. Blood and tissue samples from 102 free-ranging guignas and 262 domestic cats were collected and analyzed by PCR and sequencing. Guigna and domestic cat FeLV and FIV prevalence were very similar. Phylogenetic analysis showed guigna FeLV and FIV sequences are positioned within worldwide domestic cat virus clades with high nucleotide similarity. Guigna FeLV infection was significantly associated with fragmented landscapes with resident domestic cats. There was little evidence of clinical signs of disease in guignas. Our results contribute to the understanding of the implications of landscape perturbation and emerging diseases.

Molecular survey of selected viral pathogens in wild leopard cats (Prionailurus bengalensis) in Taiwan with an emphasis on the spatial and temporal dynamics of carnivore protoparvovirus 1

The leopard cat (Prionailurus bengalensis) was listed as an endangered species under the Wildlife Conservation Act in Taiwan in 2009. However, no study has evaluated the possible direct or indirect effects of pathogens on the Taiwanese leopard cat population. Here, we targeted viral pathogens, including carnivore protoparvovirus 1 (genus Protoparvovirus), feline leukemia virus (FeLV), feline immunodeficiency virus (FIV), coronaviruses (CoVs), and canine distemper virus (CDV), through molecular screening. The spatial and temporal dynamics of the target pathogens were evaluated. Through sequencing and phylogenetic analysis, we clarified the phylogenetic relationship of viral pathogens isolated from leopard cats and domestic carnivores. Samples from 23 live-trapped leopard cats and 29 that were found dead were collected from 2015 to 2019 in Miaoli County in northwestern Taiwan. Protoparvoviruses and CoVs were detected in leopard cats, and their prevalence (95% confidence interval) was 63.5% (50.4%–76.6%) and 8.8% (0%–18.4%), respectively. Most of the protoparvovirus sequences amplified from Taiwanese leopard cats and domestic carnivores were identical. All of the CoV sequences amplified from leopard cats were identified as feline CoV. No spatial or temporal aggregation of protoparvovirus infection in leopard cats was found in the sampling area, indicating a wide distribution of protoparvoviruses in the leopard cat habitat. We consider sympatric domestic carnivores to be the probable primary reservoir for the identified pathogens. We strongly recommend management of protoparvoviruses and feline CoV in the leopard cat habitat, particularly vaccination programs and population control measures for free-roaming dogs and cats.

Pre-eradication assessment of feral cat density and population size across Kangaroo Island, South Australia

Abstract Context Feral cats (Felis catus) are a significant threat to wildlife in Australia and globally. In Australia, densities of feral cats vary across the continent and also between the mainland and offshore islands. Densities on small islands may be at least an order of magnitude higher than those in adjacent mainland areas. To provide cat-free havens for biodiversity, cat-control and eradication programs are increasingly occurring on Australian offshore islands. However, planning such eradications is difficult, particularly on large islands where cat densities could vary considerably. Aims In the present study, we examined how feral cat densities vary among three habitats on Kangaroo Island, a large Australian offshore island for which feral cat eradication is planned. Methods Densities were compared among the following three broad habitat types: forest, forest–farmland boundaries and farmland. To detect cats, three remote-camera arrays were deployed in each habitat type, and density around each array was calculated using a spatially explicit capture–recapture framework. Key results The average feral cat density on Kangaroo Island (0.37 cats km−2) was slightly higher than that on the Australian mainland. Densities varied from 0.06 to 3.27 cats km−2 and were inconsistent within broad habitat types. Densities were highest on farms that had a high availability of macropod and sheep carcasses. The relationship between cat density and the proportion of cleared land in the surrounding area was weak. The total feral cat population of Kangaroo Island was estimated at 1629±661 (mean±s.e.) individuals. Conclusions Cat densities on Kangaroo Island are highly variable and may be locally affected by factors such as prey and carrion availability. Implications For cat eradication to be successful, resources must be sufficient to control at least the average cat density (0.37 cats km−2), with additional effort around areas of high carcass availability (where cats are likely to be at a higher density) potentially also being required.

Assessing the health risks of reintroduction: The example of the Amur leopard, Panthera pardus orientalis

Translocation of wildlife as a means of reintroducing or reinforcing threatened populations is an important conservation tool but carries health risks for the translocated animals and their progeny, as well as wildlife, domestic animals and humans in the release area. Disease risk analyses (DRA) are used to identify, prioritize and design mitigation strategies to address these threats. Here, we use a DRA undertaken for Amur leopards (Panthera pardus orientalis) to illustrate how specific methodology can optimize mitigation strategy design. A literature review identified a total of 98 infectious hazards and 28 non-infectious hazards. Separate analyses were undertaken for disease risks in leopards from hazards of source origin (captive zoo collections and the transit pathway to the Russian Far East), or of destination origin (in breeding enclosures and wider release areas); and for disease risks in other wildlife, domesticated species or humans, similarly from hazards of source or destination origin. Hazards were assessed and ranked as priority 1, priority 2, priority 3 or low priority in each of the defined scenarios. In addition, we undertook a generic assessment of stress on individual leopards. We use three examples to illustrate the process: Chlamydophila felis, canine distemper virus (CDV) and feline immunodeficiency virus (FIV). We found that many potentially expensive screening procedures could be performed prior to export of leopards, putting the onus of responsibility onto the zoo sector, for which access to diagnostic testing facilities is likely to be optimal. We discuss how our methods highlighted significant data gaps relating to pathogen prevalence in the Russian Far East and likely future unpredictability, in particular with respect to CDV. There was emphasis at all stages on record keeping, meticulous planning, design, staff training and enclosure management, which are relatively financially inexpensive. Actions to minimize stress featured at all time points in the strategy and also focussed on planning, design and management.

Molecular and serological survey of carnivore pathogens in free-roaming domestic cats of rural communities in southern Chile

Owned, free-roaming domestic cats are abundant in the Chilean countryside, having high probability of contact with wildlife and potentially participating as reservoirs of zoonotic pathogens. In the present study, 131 cats from two remote study areas (Valdivia and Chiloe Island) in southern Chile were analyzed for infection/exposure to eight pathogens. Serum samples from 112 cats were tested for antigens against feline leukemia virus (FeLV antigen-ELISA) and antibodies against feline immunodeficiency virus (FIV-ELISA) and canine distemper virus (CDV-serum neutralization), yielded occurrence of 8.9, 1.7 and 0.8% respectively. The presence of DNA of five vector-borne pathogens, piroplasmids, Ehrlichia spp., Anaplasma spp., Rickettsia spp. and Bartonella spp. was investigated in thirty cats. Overall observed occurrence was 6.6% (2/30) for both Anaplasma platys, and B. henselae, and 3.3% (1/30) for both Bartonella sp. and Theileria equi. Observed occurrence for all vector-borne pathogens in Valdivia area was significantly higher than in Chiloe Island (5/15 vs 0/15; P=0.04). Our results represent the first description of exposure to CDV and DNA detection of T. equi and A. platys in domestic cats in Chile. The results highlight the importance of performing pathogen screening in owned, free-roaming rural cats to evaluate their potential role as reservoirs of infection and vectors for disease transmission to wildlife.

Decreased Sensitivity of the Serological Detection of Feline Immunodeficiency Virus Infection Potentially Due to Imported Genetic Variants

Feline immunodeficiency virus (FIV) is a lentivirus of domestic cats worldwide. Diagnosis usually relies on antibody screening by point-of-care tests (POCT), e.g., by enzyme-linked immunosorbent assays (ELISA), and confirmation using Western blot (WB). We increasingly observed ELISA-negative, WB-positive samples and aimed to substantiate these observations using 1194 serum/plasma samples collected from 1998 to 2019 primarily from FIV-suspect cats. While 441 samples tested positive and 375 tested negative by ELISA and WB, 81 samples had discordant results: 70 were false ELISA-negative (WB-positive) and 11 were false ELISA-positive (WB-negative); 297 ambiguous results were not analyzed further. The diagnostic sensitivity and specificity of the ELISA (82% and 91%, respectively) were lower than those reported in 1995 (98% and 97%, respectively). The diagnostic efficiency was reduced from 97% to 86%. False ELISA-negative samples originated mainly (54%) from Switzerland (1995: 0%). Sixty-four false ELISA-negative samples were available for POCT (SNAP^TM/WITNESS^R): five were POCT-positive. FIV RT-PCR was positive for two of these samples and was weakly positive for two ELISA- and POCT-negative samples. Low viral loads prohibited sequencing. Our results suggest that FIV diagnosis has become more challenging, probably due to increasing travel by cats and the introduction of new FIV isolates not recognized by screening assays.

Identification of Felis catus Gammaherpesvirus 1 in Tsushima Leopard Cats (Prionailurus bengalensis euptilurus) on Tsushima Island, Japan

Felis catus gammaherpesvirus 1 (FcaGHV1) is a widely endemic infection of domestic cats. Current epidemiological data identify domestic cats as the sole natural host for FcaGHV1. The Tsushima leopard cat (TLC; Prionailurus bengalensis euptilurus) is a critically endangered species that lives only on Tsushima Island, Nagasaki, Japan. Nested PCR was used to test the blood or spleen of 89 TLCs for FcaGHV1 DNA; three (3.37%; 95% CI, 0.70⁻9.54) were positive. For TLC management purposes, we also screened domestic cats and the virus was detected in 13.02% (95% CI, 8.83⁻18.27) of 215 cats. Regarding phylogeny, the partial sequences of FcaGHV1 from domestic cats and TLCs formed one cluster, indicating that similar strains circulate in both populations. In domestic cats, we found no significant difference in FcaGHV1 detection in feline immunodeficiency virus-infected (p = 0.080) or feline leukemia virus-infected (p = 0.163) cats, but males were significantly more likely to be FcaGHV1 positive (odds ratio, 5.86; 95% CI, 2.27⁻15.14) than females. The higher frequency of FcaGHV1 detection in domestic cats than TLCs, and the location of the viral DNA sequences from both cats within the same genetic cluster suggests that virus transmission from domestic cats to TLCs is likely.

Feline APOBEC3s, Barriers to Cross-Species Transmission of FIV?

The replication of lentiviruses highly depends on host cellular factors, which defines their species-specific tropism. Cellular restriction factors that can inhibit lentiviral replication were recently identified. Feline immunodeficiency virus (FIV) was found to be sensitive to several feline cellular restriction factors, such as apolipoprotein B mRNA-editing enzyme, catalytic polypeptide-like 3 (APOBEC3) and tetherin, but FIV evolved to counteract them. Here, we describe the molecular mechanisms by which feline APOBEC3 restriction factors inhibit FIV replication and discuss the molecular interaction of APOBEC3 proteins with the viral antagonizing protein Vif. We speculate that feline APOBEC3 proteins could explain some of the observed FIV cross-species transmissions described in wild Felids.

Epidemiologic survey of feline leukemia virus in domestic cats on Tsushima Island, Japan: management strategy for Tsushima leopard cats

The Tsushima leopard cat (TLC) Prionailurus bengalensis euptilurus, a subspecies of P. bengalensis, is designated a National Natural Monument of Japan, and lives only on Tsushima Island, Nagasaki Prefecture, Japan. TLCs are threatened by various infectious diseases. Feline leukemia virus (FeLV) causes a serious infectious disease with a poor prognosis in cats. Therefore, the transmission of FeLV from Tsushima domestic cats (TDCs) to TLCs may threaten the TLC population. We investigated the FeLV infection status of both TDCs and TLCs on Tsushima Island by screening blood samples for FeLV p27 antigen and using PCR to amplify the full-length FeLV env gene. The prevalence of FeLV was 6.4% in TDCs and 0% in TLCs. We also demonstrated that the virus can replicate in the cells of TLCs, suggesting its potential cross-species transmission. The viruses in TDCs were classified as genotype I/clade 3, which is prevalent on a nearby island, based on previous studies of FeLV genotypes and FeLV epidemiology. The FeLV viruses identified on Tsushima Island can be further divided into 2 lineages within genotype I/clade 3, which are geographically separated in Kamijima and Shimojima, indicating that FeLV may have been transmitted to Tsushima Island at least twice. Monitoring FeLV infection in the TDC and TLC populations is highly recommended as part of the TLC surveillance and management strategy.

Low genetic variation in the MHC class II DRB gene and MHC-linked microsatellites in endangered island populations of the leopard cat (Prionailurus bengalensis) in Japan

Isolated populations of the leopard cat (Prionailurus bengalensis) on Tsushima and Iriomote islands in Japan are classified as subspecies P. b. euptilurus and P. b. iriomotensis, respectively. Because both populations have decreased to roughly 100, an understanding of their genetic diversity is essential for conservation. We genotyped MHC class II DRB exon 2 and MHC-linked microsatellite loci to evaluate the diversity of MHC genes in the Tsushima and Iriomote cat populations. We detected ten and four DRB alleles in these populations, respectively. A phylogenetic analysis showed DRB alleles from both populations to be closely related to those in other felid DRB lineages, indicating trans-species polymorphism. The MHC-linked microsatellites were more polymorphic in the Tsushima than in the Iriomote population. The MHC diversity of both leopard cat populations is much lower than in the domestic cat populations on these islands, probably due to inbreeding associated with founder effects, geographical isolation, or genetic drift. Our results predict low resistance of the two endangered populations to new pathogens introduced to the islands.

The presence of tick-borne diseases in domestic dogs and cats living on Iriomote-jima and Tsushima islands

The Iriomote cat and Tsushima leopard cat are endangered wildcats in Japan and inhabit only Iriomote-jima and Tsushima islands, respectively. Domestic dogs and cats living on Iriomote-jima and Tsushima islands were surveyed to clarify the interrelationship between wildcats and domestic animals regarding tick-borne disease transmission. Pathogen-derived DNA in blood samples was detected by polymerase chain reaction. Babesia gibsoni was detected in dogs of Iriomote-jima, and Hepatozoon felis and hemoplasmas were detected in domestic cats of Tsushima. Because the H. felis detected in this study was closely related to that isolated from wildcats, we suspect that common H. felis is harbored and transmitted among wildcats and domestic cats via ticks in Tsushima.

Feline Immunodeficiency Virus Vif N-Terminal Residues Selectively Counteract Feline APOBEC3s

Feline immunodeficiency virus (FIV) Vif protein counteracts feline APOBEC3s (FcaA3s) restriction factors by inducing their proteasomal degradation. The functional domains in FIV Vif for interaction with FcaA3s are poorly understood. Here, we have identified several motifs in FIV Vif that are important for selective degradation of different FcaA3s. Cats (Felis catus) express three types of A3s: single-domain A3Z2, single-domain A3Z3, and double-domain A3Z2Z3. We proposed that FIV Vif would selectively interact with the Z2 and the Z3 A3s. Indeed, we identified two N-terminal Vif motifs (12LF13 and 18GG19) that specifically interacted with the FcaA3Z2 protein but not with A3Z3. In contrast, the exclusive degradation of FcaA3Z3 was regulated by a region of three residues (M24, L25, and I27). Only a FIV Vif carrying a combination of mutations from both interaction sites lost the capacity to degrade and counteract FcaA3Z2Z3. However, alterations in the specific A3s interaction sites did not affect the cellular localization of the FIV Vif protein and binding to feline A3s. Pulldown experiments demonstrated that the A3 binding region localized to FIV Vif residues 50 to 80, outside the specific A3 interaction domain. Finally, we found that the Vif sites specific to individual A3s are conserved in several FIV lineages of domestic cat and nondomestic cats, while being absent in the FIV Vif of pumas. Our data support a complex model of multiple Vif-A3 interactions in which the specific region for selective A3 counteraction is discrete from a general A3 binding domain.

IMPORTANCE

Both human immunodeficiency virus (HIV) and feline immunodeficiency virus (FIV) Vif proteins counteract their host's APOBEC3 restriction factors. However, these two Vif proteins have limited sequence homology. The molecular interaction between FIV Vif and feline APOBEC3s are not well understood. Here, we identified N-terminal FIV Vif sites that regulate the selective interaction of Vif with either feline APOBEC3Z2 or APOBEC3Z3. These specific Vif sites are conserved in several FIV lineages of domestic cat and nondomestic cats, while being absent in FIV Vif from puma. Our findings provide important insights for future experiments describing the FIV Vif interaction with feline APOBEC3s and also indicate that the conserved feline APOBEC3s interaction sites of FIV Vif allow FIV transmissions in Felidae.

Occupancy of the Invasive Feral Cat Varies with Habitat Complexity

The domestic cat (Felis catus) is an invasive exotic in many locations around the world and is thought to be a key factor driving recent mammal declines across northern Australia. Many mammal species native to this region now persist only in areas with high topographic complexity, provided by features such as gorges or escarpments. Do mammals persist in these habitats because cats occupy them less, or despite high cat occupancy? We show that occupancy of feral cats was lower in mammal-rich habitats of high topographic complexity. These results support the idea that predation pressure by feral cats is a factor contributing to the collapse of mammal communities across northern Australia. Managing impacts of feral cats is a global conservation challenge. Conservation actions such as choosing sites for small mammal reintroductions may be more successful if variation in cat occupancy with landscape features is taken into account.

Evolution of puma lentivirus in bobcats (Lynx rufus) and mountain lions (Puma concolor) in North America

Mountain lions (Puma concolor) throughout North and South America are infected with puma lentivirus clade B (PLVB). A second, highly divergent lentiviral clade, PLVA, infects mountain lions in southern California and Florida. Bobcats (Lynx rufus) in these two geographic regions are also infected with PLVA, and to date, this is the only strain of lentivirus identified in bobcats. We sequenced full-length PLV genomes in order to characterize the molecular evolution of PLV in bobcats and mountain lions. Low sequence homology (88% average pairwise identity) and frequent recombination (1 recombination breakpoint per 3 isolates analyzed) were observed in both clades. Viral proteins have markedly different patterns of evolution; sequence homology and negative selection were highest in Gag and Pol and lowest in Vif and Env. A total of 1.7% of sites across the PLV genome evolve under positive selection, indicating that host-imposed selection pressure is an important force shaping PLV evolution. PLVA strains are highly spatially structured, reflecting the population dynamics of their primary host, the bobcat. In contrast, the phylogeography of PLVB reflects the highly mobile mountain lion, with diverse PLVB isolates cocirculating in some areas and genetically related viruses being present in populations separated by thousands of kilometers. We conclude that PLVA and PLVB are two different viral species with distinct feline hosts and evolutionary histories. Importance: An understanding of viral evolution in natural host populations is a fundamental goal of virology, molecular biology, and disease ecology. Here we provide a detailed analysis of puma lentivirus (PLV) evolution in two natural carnivore hosts, the bobcat and mountain lion. Our results illustrate that PLV evolution is a dynamic process that results from high rates of viral mutation/recombination and host-imposed selection pressure.

Cross transmission of gastrointestinal nematodes between captive neotropical felids and feral cats

Pathogen cross transmission between wildlife and domestic animals represents an extinction risk for wildlife; however, reliable verification is difficult to perform, and in some cases, it is even considered unlikely to be conducted. The aim of this work was to identify cross transmission of helminths between feral cats and captive wild felids at a zoological park in southeastern Mexico. Feces were collected from jaguars (Panthera onca), cougars (Puma concolor), ocelots (Leopardus pardalis), margays (Leopardus wiedii), and jaguarundis (Puma yagouaroundi). A flotation technique and macroscopic sieving were performed on the feces. Additionally, as part of the noxious fauna control program of the park, feral cats were captured and euthanized. To perform parasitologic studies, helminths from these animals were recovered. Toxocara cati and Trichuris campanula were shared by jaguarundis and feral cats. Ancylostoma sp. was found in jaguar and ocelot and Ancylostoma tubaeforme in feral cats. Additionally, during this study, a couple of jaguarundis died with clinical signs of trichuriasis. This is the first report of T. campanula in jaguarundi. Because feral cats roam freely in the park, transmission could occur from these vertebrates to wild felids. This study shows the risk that parasites represent to wild felids; a similar situation could be found in free-living species, especially in fragmented habitats that favor contact with domestic animals.

Epidemiological survey of tick-borne protozoal infection in iriomote cats and tsushima leopard cats in Japan

This epidemiological survey was conducted to determine the prevalence of Hepatozoon, Babesia and Theileria infection in the Iriomote cat (IC) and the Tsushima leopard cat (TLC). Blood samples from 43 ICs and 14 TLCs were collected between November 2002 and January 2012. Polymerase chain reaction and DNA sequencing analyses detected a Hepatozoon felis infection prevalence of 72.0% (31/43 cats) and 100% (14/14 cats) in ICs and TLCs, respectively. The degree of Hepatozoon parasitemia observed on blood smears ranged from 0.1 to 4.7%. However, no cases had obvious clinical signs of hepatozoonosis. Neither Babesia- nor Theileria-infected wildcats were detected in this study.

An epidemiological survey of hemoplasma infection in Iriomote cats (Prionailurus bengalensis iriomotensis)

An epidemiological survey of Iriomote cats (Prionailurus bengalensis iriomotensis) was conducted to understand the prevalence and molecular characteristics of hemotropic mycoplasma (hemoplasma). A series of ecological surveys of Iriomote cats were performed between November 2003 and September 2010. During this period, 31 Iriomote cats were captured or found, and 39 blood samples were collected. Polymerase chain reaction screening for hemoplasmas and BLAST searches revealed that 4 of the 31 cats were positive for hemoplasma infection (n=3, Mycoplasma haemofelis [Mhf]; n=1, 'Candidatus M. turicensis' [CMt]). The 4 infected cats were captured or found in the northern area of the island of Iriomote. Phylogenetic analyses revealed close relationships between Mhf and CMt isolated from Iriomote cats compared with those from domestic cats and other wild felids. In our study, we identified two species of hemoplasma in Iriomote cats. The number and location of the hemoplasma-positive cats appeared to be limited; however, continuous surveillance of hemoplasma infection in Iriomote cats is necessary.

Feline immunodeficiency virus in South America

The rapid emergence of AIDS in humans during the period between 1980 and 2000 has led to extensive efforts to understand more fully similar etiologic agents of chronic and progressive acquired immunodeficiency disease in several mammalian species. Lentiviruses that have gene sequence homology with human immunodeficiency virus (HIV) have been found in different species (including sheep, goats, horses, cattle, cats, and several Old World monkey species). Lentiviruses, comprising a genus of the Retroviridae family, cause persistent infection that can lead to varying degrees of morbidity and mortality depending on the virus and the host species involved. Feline immunodeficiency virus (FIV) causes an immune system disease in domestic cats (Felis catus) involving depletion of the CD4+ population of T lymphocytes, increased susceptibility to opportunistic infections, and sometimes death. Viruses related to domestic cat FIV occur also in a variety of nondomestic felids. This is a brief overview of the current state of knowledge of this large and ancient group of viruses (FIVs) in South America.

Emerging viruses in the Felidae: shifting paradigms

The domestic cat is afflicted with multiple viruses that serve as powerful models for human disease including cancers, SARS and HIV/AIDS. Cat viruses that cause these diseases have been studied for decades revealing detailed insight concerning transmission, virulence, origins and pathogenesis. Here we review recent genetic advances that have questioned traditional wisdom regarding the origins of virulent Feline infectious peritonitis (FIP) diseases, the pathogenic potential of Feline Immunodeficiency Virus (FIV) in wild non-domestic Felidae species, and the restriction of Feline Leukemia Virus (FeLV) mediated immune impairment to domestic cats rather than other Felidae species. The most recent interpretations indicate important new evolutionary conclusions implicating these deadly infectious agents in domestic and non-domestic felids.

When cats' ways of life interact with their viruses: a study in 15 natural populations of owned and unowned cats (Felis silvestris catus)

In natural populations, virus circulation is influenced by host behavior and physiological characteristics. Cat populations exhibit a great variability in social and spatial structure, the existence of different ways of life within a same population may also result in different epidemiological patterns. To test this hypothesis, we used a logistic regression to analyze the risk factors of Feline immunodeficiency virus (FIV), feline herpes virus (FHV), feline calicivirus (FCV), and feline parvovirus (FPV) infection in owned (fed and sheltered) and unowned (neither fed nor sheltered, unsocialized) cats living in a rural environment in the North Eastern part of France. A serological survey was carried out in 492 non-vaccinated and non-sterilized individuals from 15 populations living in the same area. The prevalence of feline leukemia virus (FeLV) was also studied, but too few were infected to analyze the risk factors of this virus. For each virus, the epidemiological pattern was different in owned and unowned cats. Unowned cats were more frequently infected by directly transmitted viruses like FIV, FHV and FCV (21.22%, 67.66%, 86.52% in unowned cats vs 9.55%, 53.88%, 77.18% in owned cats, respectively), a difference that may be explained by a more solitary and more aggressive behavior in unowned adults, and/or possibly by a higher sensitivity related to a more stressful life. On the contrary, owned cats were more frequently infected with FPV (36.41% in owned cats vs 15.61% in unowned cats), possibly as a result of their concentration around human settlements. The present study showed that owned and unowned cats living in a same area have behavioral and physiological characteristics sufficiently different to influence virus circulation. Pooling different types of cats in a single sample without taking it into account could give a wrong picture of the epidemiology of their viruses. The conclusion of this work can be extended to any epidemiological studies led in wildlife species with flexible behavior as any variations in social or spatial structure, between or within populations, could result in different virus circulation.

Fecal steroid metabolites and reproductive monitoring in a female Tsushima leopard cat (Prionailurus bengalensis euptilurus)

Although the Tsushima leopard cat (Prionailurus bengalensis euptilurus) is one of the most endangered mammals in Japan, its reproductive physiology and endocrinology have been not elucidated. The objective was to establish the non-invasive monitoring of reproductive endocrinology in a female Tsushima leopard cat and to identify the types of fecal reproductive steroid metabolites in this species. Fecal concentrations of estrogen and progestin were determined by enzyme immunoassays, from 60 d before to 60 d after the last copulation, during three pregnancies. Fecal estrogen metabolite concentrations were increased before/around the mating period and after mid-pregnancy. Fecal progestin metabolite concentrations increased after the last copulation and remained high during pregnancy. The gestation period was 65.0 ± 0.6 d (mean ± SD). Fecal extracts were separated by high-performance liquid chromatography for identification of fecal metabolites. Fecal estrogens were identified as estradiol-17β and estrone. Fecal progestins during pregnancy contained 5α-reduced pregnanes: 5α-pregnan-3α-ol-20-one, 5α-pregnan-3β-ol-20-one and 5α-pregnan-3,20-dione, and nonmetabolized progesterone was barely detected in feces. In conclusion, measurement of fecal estrogen and progestin metabolites was effective for noninvasive reproductive monitoring in the Tsushima leopard cat. An immunoassay for fecal estradiol-17β concentrations seemed useful to monitor follicular activity, whereas an immunoassay with high cross reactivity for 5α-reduced pregnanes was useful to monitor ovarian luteal activity and pregnancy.

Vif of feline immunodeficiency virus from domestic cats protects against APOBEC3 restriction factors from many felids

To get more insight into the role of APOBEC3 (A3) cytidine deaminases in the species-specific restriction of feline immunodeficiency virus (FIV) of the domestic cat, we tested the A3 proteins present in big cats (puma, lion, tiger, and lynx). These A3 proteins were analyzed for expression and sensitivity to the Vif protein of FIV. While A3Z3s and A3Z2-Z3s inhibited Deltavif FIV, felid A3Z2s did not show any antiviral activity against Deltavif FIV or wild-type (wt) FIV. All felid A3Z3s and A3Z2-Z3s were sensitive to Vif of the domestic cat FIV. Vif also induced depletion of felid A3Z2s. Tiger A3s showed a moderate degree of resistance against the Vif-mediated counter defense. These findings may imply that the A3 restriction system does not play a major role to prevent domestic cat FIV transmission to other Felidae. In contrast to the sensitive felid A3s, many nonfelid A3s actively restricted wt FIV replication. To test whether Vif(FIV) can protect also the distantly related human immunodeficiency virus type 1 (HIV-1), a chimeric HIV-1.Vif(FIV) was constructed. This HIV-1.Vif(FIV) was replication competent in nonpermissive feline cells expressing human CD4/CCR5 that did not support the replication of wt HIV-1. We conclude that the replication of HIV-1 in some feline cells is inhibited only by feline A3 restriction factors and the absence of the appropriate receptor or coreceptor.

Feline immunodeficiency virus (FIV) in wild Pallas' cats

Feline immunodeficiency virus (FIV), a feline lentivirus related to HIV, causes immune dysfunction in domestic and wild cats. The Pallas' cat is the only species from Asia known to harbor a species-specific strain of FIV designated FIV(Oma) in natural populations. Here, a 25% seroprevalence of FIV is reported from 28 wild Mongolian Pallas' cats sampled from 2000 to 2008. Phylogenetic analysis of proviral RT-Pol from eight FIV(Oma) isolates from Mongolia, Russia, China and Kazakhstan reveals a unique monophyletic lineage of the virus within the Pallas' cat population, most closely related to the African cheetah and leopard FIV strains. Histopathological examination of lymph node and spleen from infected and uninfected Pallas' cats suggests that FIV(Oma) causes immune depletion in its' native host.

Restrictions to cross-species transmission of lentiviral infection gleaned from studies of FIV

More than 40 species of primates and over 20 species of cats harbor antibodies that sero-react to lentiviral antigens. In nearly all cases where viral genetic analysis has been conducted, each host species is infected with a unique lentivirus. Though lentivirus clades within a species can be substantially divergent, they are typically monophyletic within that species. A notable significant departure from this observation is apparent cross-species transmission of FIV between bobcats (Lynx rufus) and pumas (Puma concolor) in Southern California that has occurred at least three times; evidence from one bobcat sequence suggests this cross-over may have also occurred in Florida between bobcats and the endangered Florida panther. Several other isolated reports demonstrate cross-species transmission of FIV isolates among captive animals housed in close proximity, and it is well established that HIV-1 and HIV-2 arose from human contact with SIV-infected non-human primates. Using an experimental model, we have determined that domestic cats (Felis catus) are susceptible to FIVs originating from pumas or lions. While infections are initially replicative, and animals seroconvert, within a relatively short period of time circulating virus is reduced to nearly undetectable levels in a majority of animals. This diminution of viral load is proportional to initial viral peak. Although viral reservoirs can be identified in gastrointestinal tissues, most viral genomes recovered peripherally are highly mutated, suggesting that the non-adapted host successfully inhibits normal viral replication, leading to replication incompetent viral progeny. Mechanisms possible for such restriction of cross-species infections in natural settings include: (1) Lack of contact conducive to lentiviral transmission between infected and shedding animals of different species; (2) Lack of suitable receptor repertoire to allow viral entry to susceptible cells of a new species; (3) Cellular machinery in the new host sufficiently divergent from the primary host to support viral replication (i.e. passive unfacilitated viral replication); (4) Intracellular restriction mechanisms present in the new host that is able to limit viral replication (i.e. active interrupted viral replication. These include factors that limit uncoating, replication, packaging, and virion release); (5) Unique ability of new host to raise sterilizing adaptive immunity, resulting in aborted infection and inability to spread infections among con-specifics; or (6) Production of defective or non-infectious viral progeny that lack cellular cofactors to render them infectious to con-specifics (i.e. particles lacking appropriate cellular components in viral Env to render them infectious to other animals of the same species). Data to support or refute the relative importance of each of these possibilities is described in this review. Insights based on our in vivo cross-species model suggest intracellular restriction mechanisms effectively inhibit rapid inter-specific transmission of lentiviruses. Further, limited contact both within and between species in natural populations is highly relevant to limiting the opportunity for spread of FIV strains. Studies of naturally occurring SIV and innate host restriction systems suggest these same two mechanisms are significant factors inhibiting widespread cross-species transmission of lentiviruses among primate species as well.

Restriction of feline retroviruses: lessons from cat APOBEC3 cytidine deaminases and TRIM5alpha proteins

The interplay between viral and cellular factors determines the outcome of an initial contact between a given virus and its natural host or upon encounter of a novel host. Thus, the potential of inducing disease as well as crossing host species barriers are the consequences of the molecular interactions between the parasite and its susceptible, tolerant or resistant host. Cellular restriction factors, for instance APOBEC3 and TRIM5 proteins, targeting defined pathogens or groups of pathogens as well as viral genes counter-acting these cellular defense systems are of prime importance in this respect and may even represent novel targets for prevention and therapy of virus infections. Due to the importance of host-encoded antiviral restriction and viral counter-defense for pathogenicity and host tropism, the responsible molecular factors and mechanisms are currently under intense investigation. In this review we will introduce host restriction and retroviral counter-defense systems with a special emphasis on the cat and its naturally occurring exogenous retroviruses which is a valid model for human disease, a model that will contribute to increase our basic understanding and potential applications of these important aspects of host-virus interaction.

Truncation of TRIM5 in the Feliformia explains the absence of retroviral restriction in cells of the domestic cat

TRIM5alpha mediates a potent retroviral restriction phenotype in diverse mammalian species. Here, we identify a TRIM5 transcript in cat cells with a truncated B30.2 capsid binding domain and ablated restrictive function which, remarkably, is conserved across the Feliformia. Cat TRIM5 displayed no restriction activity, but ectopic expression conferred a dominant negative effect against human TRIM5alpha. Our findings explain the absence of retroviral restriction in cat cells and suggest that disruption of the TRIM5 locus has arisen independently at least twice in the Carnivora, with implications concerning the evolution of the host and pathogen in this taxon.

When domestic cat (Felis silvestris catus) population structures interact with their viruses

Many theoretical studies have proposed different causal mechanisms by which the structure of a host population could have important implications for life history traits of pathogens. However, little information is available from real systems to test these hypotheses. The domestic cat, Felis silvestris catus, whose populations exhibit a great variability in social and spatial structure, represent an ideal case study to assess this question. In the present article, we show how cat population structure may have influenced the evolution of feline viruses and, in return, how these viruses may have modified the genetic structure of cat populations. To cite this article: D. Pontier et al., C. R. Biologies 332 (2009).

Ocelots on Barro Colorado Island are infected with feline immunodeficiency virus but not other common feline and canine viruses

Transmission of pathogens from domestic animals to wildlife populations (spill-over) has precipitated local wildlife extinctions in multiple geographic locations. Identifying such events before they cause population declines requires differentiating spillover from endemic disease, a challenge complicated by a lack of baseline data from wildlife populations that are isolated from domestic animals. We tested sera collected from 12 ocelots (Leopardus pardalis) native to Barro Colorado Island, Panama, which is free of domestic animals, for antibodies to feline herpes virus, feline calicivirus, feline corona virus, feline panleukopenia virus, canine distemper virus, and feline immunodeficiency virus (FIV), typically a species-specific infection. Samples also were tested for feline leukemia virus antigens. Positive tests results were only observed for FIV; 50% of the ocelots were positive. We hypothesize that isolation of this population has prevented introduction of pathogens typically attributed to contact with domestic animals. The high density of ocelots on Barro Colorado Island may contribute to a high prevalence of FIV infection, as would be expected with increased contact rates among conspecifics in a geographically restricted population.

Could FIV zoonosis responsible of the breakdown of the pathocenosis which has reduced the European CCR5-Delta32 allele frequencies?

Background

In Europe, the north-south downhill cline frequency of the chemokine receptor CCR5 allele with a 32-bp deletion (CCR5-Δ32) raises interesting questions for evolutionary biologists. We had suggested first that, in the past, the European colonizers, principally Romans, might have been instrumental of a progressively decrease of the frequencies southwards. Indeed, statistical analyses suggested strong negative correlations between the allele frequency and historical parameters including the colonization dates by Mediterranean civilisations. The gene flows from colonizers to native populations were extremely low but colonizers are responsible of the spread of several diseases suggesting that the dissemination of parasites in naive populations could have induced a breakdown rupture of the fragile pathocenosis changing the balance among diseases. The new equilibrium state has been reached through a negative selection of the null allele.

Results

Most of the human diseases are zoonoses and cat might have been instrumental in the decrease of the allele frequency, because its diffusion through Europe was a gradual process, due principally to Romans; and that several cat zoonoses could be transmitted to man. The possible implication of a feline lentivirus (FIV) which does not use CCR5 as co-receptor is discussed. This virus can infect primate cells in vitro and induces clinical signs in macaque. Moreover, most of the historical regions with null or low frequency of CCR5-Δ32 allele coincide with historical range of the wild felid species which harbor species-specific FIVs.

Conclusion

We proposed the hypothesis that the actual European CCR5 allelic frequencies are the result of a negative selection due to a disease spreading. A cat zoonosis, could be the most plausible hypothesis. Future studies could provide if CCR5 can play an antimicrobial role in FIV pathogenesis. Moreover, studies of ancient DNA could provide more evidences regarding the implications of zoonoses in the actual CCR5-Δ32 distribution.

FIV cross-species transmission: an evolutionary prospective

Feline and primate immunodeficiency viruses (FIVs, SIVs, and HIV) are transmitted via direct contact (e.g. fighting, sexual contact, and mother–offspring transmission). This dynamic likely poses a behavioral barrier to cross-species transmission in the wild. Recently, several host intracellular anti-viral proteins that contribute to species-specificity of primate lentiviruses have been identified revealing adaptive mechanisms that further limit spread of lentiviruses between species. Consistent with these inter-species transmission barriers, phylogenetic evidence supports the prediction that FIV transmission is an exceedingly rare event between free-ranging cat species, though it has occurred occasionally in captive settings. Recently we documented that puma and bobcats in Southern California share an FIV strain, providing an opportunity to evaluate evolution of both viral strains and host intracellular restriction proteins. These studies are facilitated by the availability of the 2× cat genome sequence annotation. In addition, concurrent viral and host genetic analyses have been used to track patterns of migration of the host species and barriers to transmission of the virus within the African lion. These studies illustrate the utility of FIV as a model to discover the variables necessary for establishment and control of lentiviral infections in new species.

Frequent transmission of immunodeficiency viruses among bobcats and pumas

With the exception of human immunodeficiency virus (HIV), which emerged in humans after cross-species transmissions of simian immunodeficiency viruses from nonhuman primates, immunodeficiency viruses of the family Lentiviridae represent species-specific viruses that rarely cross species barriers to infect new hosts. Among the Felidae, numerous immunodeficiency-like lentiviruses have been documented, but only a few cross-species transmissions have been recorded, and these have not been perpetuated in the recipient species. Lentivirus seroprevalence was determined for 79 bobcats (Lynx rufus) and 31 pumas (Puma concolor) from well-defined populations in Southern California. Partial genomic sequences were subsequently obtained from 18 and 12 seropositive bobcats and pumas, respectively. Genotypes were analyzed for phylogenic relatedness and genotypic composition among the study set and archived feline lentivirus sequences. This investigation of feline immunodeficiency virus infection in bobcats and pumas of Southern California provides evidence that cross-species infection has occurred frequently among these animals. The data suggest that transmission has occurred in multiple locations and are most consistent with the spread of the virus from bobcats to pumas. Although the ultimate causes remain unknown, these transmission events may occur as a result of puma predation on bobcats, a situation similar to that which fostered transmission of HIV to humans, and likely represent the emergence of a lentivirus with relaxed barriers to cross-species transmission. This unusual observation provides a valuable opportunity to evaluate the ecological, behavioral, and molecular conditions that favor repeated transmissions and persistence of lentivirus between species.

FIV as a Model for HIV: An Overview

Animal models for human immunodeficiency virus (HIV) infection play a key role in understanding the pathogenesis of AIDS and the development of therapeutic agents and vaccines. As the only lentivirus that causes an immunodeficiency resembling that of HIV infection, in its natural host, feline immunodeficiency virus (FIV) has been a unique and powerful model for AIDS research. FIV was first described in 1987 by Niels Pedersen and co-workers as the causative agent for a fatal immunodeficiency syndrome observed in cats housed in a cattery in Petaluma, California. Since this landmark observation, multiple studies have shown that natural and experimental infection of cats with biological isolates of FIV produces an AIDS syndrome very similar in pathogenesis to that observed for human AIDS. FIV infection induces an acute viremia associated with Tcell alterations including depressed CD4 :CD8 T-cell ratios and CD4 T-cell depletion, peripheral lymphadenopathy, and neutropenia. In later stages of FIV infection, the host suffers from chronic persistent infections that are typically self-limiting in an immunocompetent host, as well as opportunistic infections, chronic diarrhea and wasting, blood dyscracias, significant CD4 T-cell depletion, neurologic disorders, and B-cell lymphomas. Importantly, chronic FIV infection induces a progressive lymphoid and CD4 T-cell depletion in the infected cat. The primary mode of natural FIV transmission appears to be blood-borne facilitated by fighting and biting. However, experimental infection through transmucosal routes (rectal and vaginal mucosa and perinatal) have been well documented for specific FIV isolates. Accordingly, FIV disease pathogenesis exhibits striking similarities to that described for HIV-1 infection.

Going wild: lessons from naturally occurring T-lymphotropic lentiviruses

Over 40 nonhuman primate (NHP) species harbor species-specific simian immunodeficiency viruses (SIVs). Similarly, more than 20 species of nondomestic felids and African hyenids demonstrate seroreactivity against feline immunodeficiency virus (FIV) antigens. While it has been challenging to study the biological implications of nonfatal infections in natural populations, epidemiologic and clinical studies performed thus far have only rarely detected increased morbidity or impaired fecundity/survival of naturally infected SIV- or FIV-seropositive versus -seronegative animals. Cross-species transmissions of these agents are rare in nature but have been used to develop experimental systems to evaluate mechanisms of pathogenicity and to develop animal models of HIV/AIDS. Given that felids and primates are substantially evolutionarily removed yet demonstrate the same pattern of apparently nonpathogenic lentiviral infections, comparison of the biological behaviors of these viruses can yield important implications for host-lentiviral adaptation which are relevant to human HIV/AIDS infection. This review therefore evaluates similarities in epidemiology, lentiviral genotyping, pathogenicity, host immune responses, and cross-species transmission of FIVs and factors associated with the establishment of lentiviral infections in new species. This comparison of consistent patterns in lentivirus biology will expose new directions for scientific inquiry for understanding the basis for virulence versus avirulence.

Fecal DNA Analysis for Identifying Species and Sex of Sympatric Carnivores: A Noninvasive Method for Conservation on the Tsushima Islands, Japan

Fecal analysis is a useful tool for the investigation of food habits and species identity in mammals. However, it is generally difficult to identify the species based on the morphological features and contents of feces deposited by mammals of similar body size. Therefore we developed noninvasive DNA analysis methods using fecal samples for identification of the species and sex of four small sympatric carnivores living on the Tsushima Islands of Japan: the leopard cat (Felis bengalensis), Japanese marten (Martes melampus), Siberian weasel (Mustela sibirica), and feral cat (Felis catus). Based on DNA sequence data from previous phylogenetic studies, we designed species-specific primers for polymerase chain reaction (PCR) amplification of the partial mitochondrial cytochrome b gene (112-347 bp) to identify the species and primers for the partial SRY gene (135 bp) to determine the sex. Due to the adjustment of PCR conditions, those specific DNA fragments were successfully amplified and then applied for species and sex identification. Nucleotide sequences obtained from the PCR products corresponded with cytochrome b sequences of the carnivore species expected. The protocol developed could be a valuable tool in the management and conservation of the four carnivore species occurring on the Tsushima Islands.

Seroprevalence and genomic divergence of circulating strains of feline immunodeficiency virus among Felidae and Hyaenidae species

Feline immunodeficiency virus (FIV) infects numerous wild and domestic feline species and is closely related to human immunodeficiency virus (HIV) and simian immunodeficiency virus (SIV). Species-specific strains of FIV have been described for domestic cat (Felis catus), puma (Puma concolor), lion (Panthera leo), leopard (Panthera pardus), and Pallas' cat (Otocolobus manul). Here, we employ a three-antigen Western blot screening (domestic cat, puma, and lion FIV antigens) and PCR analysis to survey worldwide prevalence, distribution, and genomic differentiation of FIV based on 3,055 specimens from 35 Felidae and 3 Hyaenidae species. Although FIV infects a wide variety of host species, it is confirmed to be endemic in free-ranging populations of nine Felidae and one Hyaenidae species. These include the large African carnivores (lion, leopard, cheetah, and spotted hyena), where FIV is widely distributed in multiple populations; most of the South American felids (puma, jaguar, ocelot, margay, Geoffroy's cat, and tigrina), which maintain a lower FIV-positive level throughout their range; and two Asian species, the Pallas' cat, which has a species-specific strain of FIV, and the leopard cat, which has a domestic cat FIV strain in one population. Phylogenetic analysis of FIV proviral sequence demonstrates that most species for which FIV is endemic harbor monophyletic, genetically distinct species-specific FIV strains, suggesting that FIV transfer between cat species has occurred in the past but is quite infrequent today.

Genetic diversity in domestic cats Felis catus of the Tsushima Islands, based on mitochondrial DNA cytochrome b and control region nucleotide sequences

Nucleotide sequences of mitochondrial DNA (mtDNA) of 50 domestic cats (Felis catus) obtained from the Tsushima Islands were determined and the genetic diversity was analyzed. In the cats, six haplotypes of the complete cytochrome b sequences (1,140 base-pairs, bp) and ten haplotypes of the partial control region sequences (350 bp) were identified. Haplotypes obtained from both genes showed existence of at least 11 maternal lineages of domestic cats in Tsushima. Mean values of polymorphic site numbers and sequences differences in the control region were 2.4 times and 1.8 times higher than those in the cytochrome b gene, respectively. Our results support the idea that the evolutionary rate of the control region was faster than that of the cytochrome b as reported in other mammals. Molecular phylogenetic trees showed the similar clustering of haplotypes for both genes. Meanwhile, no individual variations within the Tsushima leopard cat (Felis bengalensis euptilura), which is native to Tsushima, were observed, possibly as a result of genetic drift in the small ancestral population by geographical isolation. In contrast, the diversity of the domestic cat population was higher than that of the leopard cats, because the genetic variability of the former's founders, which were repeatedly brought to Tsushima in the past, still remains. In addition, no sequences of the leopard cat mtDNA were detected in any domestic cats. However, because the possibility that the domestic cat would crossbreed with the leopard cat cannot be denied, genetic monitoring of two species is necessary to biological conservation in Tsushima.

Benign giant cell tumour of tendon sheaths in a European Lynx (Lynx lynx)

The histological, histochemical, immunohistochemical and ultrastructural features of a benign giant cell tumour (BGCT) of tendon sheaths in a 12-year-old male European lynx (Lynx lynx) are reported herein. The neoplastic mass involved the subcutaneous and inter-muscular tissues of the first, second, third and fourth digit of the left forelimb, from the phalanxes up to the carpus. The tumour appeared as a grey-whitish tissue mottled with darker areas, along with several scattered foci of orange colour. Histologically, the lesion consisted of a mixed population of numerous, multinucleated giant cells and epithelioid or spindle-shaped mononuclear cells embedded in a loose, highly vascular stroma. Neoplastic cells lined cleft formations and synovial-like projections into cystic spaces. No osteoid matrix could be detected. Haemorrhage and necrosis were also observed. The mononuclear and the giant cells were tartrate-resistant acid phosphatase and periodic acid-Schiff positive, being also immunohistochemically reactive for lysozyme and vimentin, with a few cells showing immunopositivity also for alpha-1-antitrypsin. Ultrastructurally, histiocyte-like cells, fibroblast-like cells and multinucleated giant cells were observed, but no virus-like particles could be detected in any of the above cell types. The BGCT of tendon sheaths, a fairly uncommon neoplasm in animals, has not been previously reported in the lynx.

Patterns of feline immunodeficiency virus multiple infection and genome divergence in a free-ranging population of African lions

Feline immunodeficiency virus (FIV) is a lentivirus that causes AIDS-like immunodeficiency disease in domestic cats. Free-ranging lions, Panthera leo, carry a chronic species-specific strain of FIV, FIV-Ple, which so far has not been convincingly connected with immune pathology or mortality. FIV-Ple, harboring the three distinct strains A, B, and C defined by pol gene sequence divergences, is endemic in the large outbred population of lions in the Serengeti ecosystem in Tanzania. Here we describe the pattern of variation in the three FIV genes gag, pol-RT, and pol-RNase among lions within 13 prides to assess the occurrence of FIV infection and coinfection. Genome diversity within and among FIV-Ple strains is shown to be large, with strain divergence for each gene approaching genetic distances observed for FIV between different species of cats. Multiple in fections with two or three strains were found in 43% of the FIV-positive individuals based on pol-RT sequence analysis, which may suggest that antiviral immunity or interference evoked by one strain is not consistently protective against infection by a second. This comprehensive study of FIV-Ple in a free-ranging population of lions reveals a dynamic transmission of virus in a social species that has historically adapted to render the virus benign.

Contrastive prevalence of feline retrovirus infections between northern and southern Vietnam

The prevalence of infections with three feline retroviruses; feline leukemia virus (FeLV), feline immunodeficiency virus (FIV) and feline foamy virus (FeFV), was examined in domestic cats (Felis catus) and leopard cats (Felis bengalensis) in southern Vietnam in 1998. We then compared this data with our previous study in northern Vietnam in 1997. None of the cats had FeLV antigens in both the northern and southern areas. In contrast, there is a great distinction in the seropositivity of FIV. Twenty-two percent of domestic cats had FIV antibodies whereas no FIV positive cats were detected in northern area. FIV may have entered southern Vietnam recently and spread rapidly. FeFV infections were found in both areas, suggesting that FeFV might be present in the cat populations in Vietnam from the earliest time.