First evidence of canine distemper in Brazilian free-ranging felids

Evidence-based legislation, strong institutions and consensus needed to mitigate the negative impacts of free-ranging dogs

Dogs bring many benefits to our society but, if not properly managed, they can be detrimental for humans, livestock and wildlife. We highlight the increasing problems associated with free-ranging dogs using examples from two regions of the world where this issue is pervasive, India and South America. In these regions, free-ranging dogs spread diseases, injure people, harm biodiversity, and negatively impact human livelihoods. We discuss why mitigating these deleterious effects can be extremely complicated because there are diverse challenges such as: (a) a lack of or inappropriate legislations concerning free-ranging dog management and human-dog interactions, (b) unregulated intentional and unintentional feeding of free-ranging dogs, (c) limitations of animal shelters, (d) non-responsible ownership, and (e) uncontrolled dog populations. As the management of animal species is usually shaped by differing interests, existing policies and regulations, views and social influence of stakeholders, power asymmetries between interested parties is yet another challenge in this regard. We need evidence-based legislations and strong institutions (e.g., public health and conservation institutions) that are capable of implementing governance principles and managing the complexities of this socio-ecological system by taking science-based decisions, and balancing power asymmetries to promote consensus.

Serological Survey for Three Canine Viruses in Brazilian Wild Carnivores : Antibodies Against Canine Viruses in Wild Carnivores

We evaluated the presence of antibodies against CaHV-1, CDV, and CPV-2 in serum samples from Brazilian wild carnivore species. Nine maned wolves and six crab-eating foxes were tested for CaHV-1 and CDV by virus neutralization test and CPV-2 by hemagglutination inhibition assay. Antibodies to CaHV-1, CDV, and CPV-2 were detected in serum samples of 1 (6.7%), 5 (33.3%), and 10 (66.7%) wild carnivores, respectively. Two maned wolves and one crab-eating fox were seropositive simultaneously for CDV and CPV-2. Antibodies against all viruses were detected in one crab-eating fox. This is the first report of CaHV-1 antibody detection in crab-eating foxes.

Identification of a new polymorphism on the wild-type canine distemper virus genome: could this contribute to vaccine failures?

The canine distemper virus (CDV) is responsible for a multisystem infectious disease with high prevalence in dogs and wild carnivores and has vaccination as the main control measure. However, recent studies show an increase in cases including vaccinated dogs in different parts of the world. There are several reasons for vaccine failures, including differences between vaccine strains and wild-type strains. In this study, a phylogenetic analysis of CDV strains from samples of naturally infected, vaccinated, and symptomatic dogs in Goiânia, Goiás, Brazil was performed with partial sequencing of the hemagglutinin (H) gene of CDV. Different sites of amino acid substitutions were found, and one strain had the Y549H mutation, typically present in samples from wild animals. Substitutions in epitopes (residues 367, 376, 379, 381, 386, and 388) that may interfere with the vaccine's ability to provide adequate protection against infection for CDV were observed. The identified strains were grouped in the South America 1/Europe lineage, with a significant difference from other lineages and vaccine strains. Twelve subgenotypes were characterized, considering a nucleotide identity of at least 98% among the strains. These findings highlight the relevance of canine distemper infection and support the need better monitoring of the circulating strains that contribute to elucidate if there is a need for vaccine update.

Canine distemper virus and canine adenovirus type-2 infections in neotropical otters (Lontra longicaudis) from Southern Brazil

All descriptions of infectious diseases affecting otters were published in the Northern Hemisphere, with no occurrence identified in neotropical otters (Lontra longicaudis). Consequently, a retrospective histopathological study using archival tissue samples from six free-living neotropical otters was done to investigate the possible occurrence of disease patterns associated with common viral infectious disease agents of the domestic dogs. Immunohistochemical (IHC) assays were designed to identify intralesional tissue antigens of canine distemper virus (CDV), and canine adenovirus-1 (CAdV-1) and canine adenovirus-2 (CAdV-2). The most frequent histopathological patterns diagnosed were interstitial pneumonia (83.33%; 6/5) and hepatocellular vacuolar degeneration (50%; 3/6). IHC identified intralesional intracytoplasmic immunoreactivity to CDV antigens in all otters evaluated, with positive immunolabeling occurring within epithelial cells of the lungs, stomach, kidneys, and liver, and skin. Intracytoplasmic CAdV-2 antigens were identified within epithelial cells of the peribronchial glands in four otters with interstitial pneumonia. These findings resulted in singular and simultaneous infections in these neotropical otters, represented the first report of concomitant infections by CDV and CAdV-2 in free-living neotropical otters from the Southern Hemisphere, and suggested that this mammalian species is susceptible to infections by viral disease agents common to the domestic dogs and may develop similar histopathologic disease patterns.

Dog predation by jaguars in a tourist town on the Mexican Caribbean

Invasion of humans and dogs into the jaguars’ habitat opens the way for future negative events. Dog predation by jaguars has only been recorded anecdotally, despite the high risk of pathogen transmission and the potential conflict due to pet predation. In this study, we document jaguar attacks on dogs in Mahahual, Quintana Roo, Mexico, a tourist town in the Mexican Caribbean. In addition, we describe an initiative designed to prevent jaguar persecution by constructing night houses for dogs at the most recent attack sites. A total of 20 attacks were recorded in the last nine years, most of them fatal (60%) on medium-sized dogs (70%), at night (95%) and during the dry season (65%). Half of the attacks occurred in the north of Mahahual´s coastline and the other half in the south. Attacks in the south were concentrated between 0 to 10 km away from the village, while in the north they were dispersed over distances between 0 and > 30 km. Thirty-eight night houses were constructed covering almost 45 km of the 135 km of Mahahual’s coastline. Further research is required to understand the importance of dogs in the jaguar diet and the impact of dog predation on the health and disease ecology of jaguar populations.

Sylvatic Canine Morbillivirus in Captive Panthera Highlights Viral Promiscuity and the Need for Better Prevention Strategies

Canine Distemper Virus (CDV) is a multi-host morbillivirus that infects virtually all Carnivora and a few non-human primates. Here we describe a CDV outbreak in an exotic felid rescue center that led to the death of eight felids in the genus Panthera. Similar to domestic dogs and in contrast to previously described CDV cases in Panthera, severe pneumonia was the primary lesion and no viral antigens or CDV-like lesions were detected in the central nervous system. Four tigers succumbed to opportunistic infections. Viral hemagglutinin (H)-gene sequence was up to 99% similar to strains circulating contemporaneously in regional wildlife. CDV lesions in raccoons and skunk were primarily encephalitis. A few affected felids had at least one previous vaccination for CDV, while most felids at the center were vaccinated during the outbreak. Panthera sharing a fence or enclosure with infected conspecifics had significantly higher chances of getting sick or dying, suggesting tiger-tiger spread was more likely than recurrent spillover. Prior vaccination was incomplete and likely not protective. This outbreak highlights the need for further understanding of CDV epidemiology for species conservation and public health.

Comparative leucocyte populations between two sympatric carnivores (Nasua narica and Procyon lotor)

Coatis (Nasua narica) and raccoons (Procyon lotor) potentially play an important role in zoonotic diseases because they may carry pathogens and can transmit them to humans. To date, our understanding of the immune function of these two carnivores is deficient. The aim of this study was to compare the number of leucocyte subtypes and the phagocytic capacity between the coati and the raccoon. Blood samples were collected, and leucocyte subtypes were characterized and counted by flow cytometry and microscopy, respectively. Phagocytosis was analysed by kinetic assay. Differences in leucocytes between these two species were found; the total count of neutrophils was higher in raccoons than in coatis, but lymphocytes and eosinophils were higher in coatis than in raccoons. Antigen reduction was more rapid for the coatis. However, raccoons had a higher efficient endocytic process than coatis. This study provides the basis for understanding the procyonid immune system, which informs conservation, particularly since some procyonids are imperilled.

Evolution and Interspecies Transmission of Canine Distemper Virus-An Outlook of the Diverse Evolutionary Landscapes of a Multi-Host Virus

Canine distemper virus (CDV) is a worldwide distributed virus which belongs to the genus Morbillivirus within the Paramyxoviridae family. CDV spreads through the lymphatic, epithelial, and nervous systems of domestic dogs and wildlife, in at least six orders and over 20 families of mammals. Due to the high morbidity and mortality rates and broad host range, understanding the epidemiology of CDV is not only important for its control in domestic animals, but also for the development of reliable wildlife conservation strategies. The present review aims to give an outlook of the multiple evolutionary landscapes and factors involved in the transmission of CDV by including epidemiological data from multiple species in urban, wild and peri-urban settings, not only in domestic animal populations but at the wildlife interface. It is clear that different epidemiological scenarios can lead to the presence of CDV in wildlife even in the absence of infection in domestic populations, highlighting the role of CDV in different domestic or wild species without clinical signs of disease mainly acting as reservoirs (peridomestic and mesocarnivores) that are often found in peridomestic habits triggering CDV epidemics. Another scenario is driven by mutations, which generate genetic variation on which random drift and natural selection can act, shaping the genetic structure of CDV populations leading to some fitness compensations between hosts and driving the evolution of specialist and generalist traits in CDV populations. In this scenario, the highly variable protein hemagglutinin (H) determines the cellular and host tropism by binding to signaling lymphocytic activation molecule (SLAM) and nectin-4 receptors of the host; however, the multiple evolutionary events that may have facilitated CDV adaptation to different hosts must be evaluated by complete genome sequencing. This review is focused on the study of CDV interspecies transmission by examining molecular and epidemiological reports based on sequences of the hemagglutinin gene and the growing body of studies of the complete genome; emphasizing the importance of long-term multidisciplinary research that tracks CDV in the presence or absence of clinical signs in wild species, and helping to implement strategies to mitigate the infection. Integrated research incorporating the experience of wildlife managers, behavioral and conservation biologists, veterinarians, virologists, and immunologists (among other scientific areas) and the inclusion of several wild and domestic species is essential for understanding the intricate epidemiological dynamics of CDV in its multiple host infections.

Molecular and serological surveys of canine distemper virus: A meta-analysis of cross-sectional studies

BACKGROUND

Canine morbillivirus (canine distemper virus, CDV) persists as a serious threat to the health of domestic dogs and wildlife. Although studies have been conducted on the frequency and risk factors associated with CDV infection, there are no comprehensive data on the current epidemiological magnitude in the domestic dog population at regional and national levels. Therefore, we conducted a cross-sectional study and included our results in a meta-analysis to summarize and combine available data on the frequency and potential risk factors associated with CDV infection.

METHODS

For the cross-sectional study, biological samples from dogs suspected to have canine distemper (CD) were collected and screened for viral RNA. Briefly, the PRISMA protocol was used for the meta-analysis, and data analyses were performed using STATA IC 13.1 software.

RESULTS

CDV RNA was detected in 34% (48/141) of dogs suspected to have CD. Following our meta-analysis, 53 studies were selected for a total of 11,527 dogs. Overall, the pooled frequency of CDV positivity based on molecular and serological results were 33% (95% CI: 23-43) and 46% (95% CI: 36-57), respectively. The pooled subgroup analyses of clinical signs, types of biological samples, diagnostic methods and dog lifestyle had a wide range of CDV positivity (range 8-75%). Free-ranging dogs (OR: 1.44, 95% CI: 1.05-1.97), dogs >24 months old (OR: 1.83, 95% CI: 1.1-3) and unvaccinated dogs (OR: 2.92, 95% CI: 1.26-6.77) were found to be positively associated with CDV infection. In contrast, dogs <12 months old (OR: 0.36, 95% CI: 0.20-0.64) and dogs with a complete anti-CDV vaccination (OR: 0.18, 95% CI: 0.05-0.59) had a negative association.

CONCLUSION

Considering the high frequency of CDV positivity associated with almost all the variables analyzed in dogs, it is necessary to immediately and continuously plan mitigation strategies to reduce the CDV prevalence, especially in determined endemic localities.

Molecular detection of viral agents in free-ranging and captive neotropical felids in Brazil

We describe molecular testing for felid alphaherpesvirus 1 (FHV-1), carnivore protoparvovirus 1 (CPPV-1), feline calicivirus (FCV), alphacoronavirus 1 (feline coronavirus [FCoV]), feline leukemia virus (FeLV), feline immunodeficiency virus (FIV), and canine distemper virus (CDV) in whole blood samples of 109 free-ranging and 68 captive neotropical felids from Brazil. Samples from 2 jaguars ( Panthera onca) and 1 oncilla ( Leopardus tigrinus) were positive for FHV-1; 2 jaguars, 1 puma ( Puma concolor), and 1 jaguarundi ( Herpairulus yagouaroundi) tested positive for CPPV-1; and 1 puma was positive for FIV. Based on comparison of 103 nucleotides of the UL24-UL25 gene, the FHV-1 sequences were 99-100% similar to the FHV-1 strain of domestic cats. Nucleotide sequences of CPPV-1 were closely related to sequences detected in other wild carnivores, comparing 294 nucleotides of the VP1 gene. The FIV nucleotide sequence detected in the free-ranging puma, based on comparison of 444 nucleotides of the pol gene, grouped with other lentiviruses described in pumas, and had 82.4% identity with a free-ranging puma from Yellowstone Park and 79.5% with a captive puma from Brazil. Our data document the circulation of FHV-1, CPPV-1, and FIV in neotropical felids in Brazil.

Multiple-host pathogens in domestic hunting dogs in Nicaragua's Bosawás Biosphere Reserve

Nicaragua's Bosawás Biosphere Reserve is a vast forested area inhabited largely by indigenous Mayangna and Miskitu people. Most Bosawás residents rely on subsistence hunting and swidden agriculture, and hunting dogs are important for finding and securing wild game. We investigated the health of hunting dogs in three communities differing in location, size, and economy. Dogs in all communities were nutritionally compromised and experienced a heavy burden of disease. Seroprevalence of canine distemper, canine parvovirus, Rickettsia rickettsii, and Leptospira spp. exceeded 50% of dogs. At least one dog was actively shedding leptospires in urine, and many dogs were anemic and/or dehydrated. These dogs interact with wildlife in the forest and humans and domestic livestock in the communities, and may therefore serve as sources of zoonotic and wildlife diseases. Bosawás represents one of the largest intact tracts of habitat for jaguars (Panthera onca) in Central America, and given that these communities are located within the forest, jaguars may be at risk from disease spillover from hunting dogs. Dog owners reported that four of 49 dogs had been attacked and killed by jaguars in the past year, and that retaliatory killing of jaguars was sometimes practiced. Disease spillover from dogs to wildlife could occur both in the course of dogs' hunting activities as well as during jaguar attacks. A better understanding of dog depredation by jaguars, pathogen exposure in jaguars, and a management strategy for the hunting dog population, are urgently needed to mitigate these dual threats to jaguars, improve the lives of hunting dogs, and safeguard the health of their owners.

Hepatozoon SPP. Infect Free-Ranging Jaguars (Panthera onca) in Brazil

This study investigated the presence of Hepatozoon spp. in jaguars ( Panthera onca ) and domestic animals in the Cerrado, Amazon, and Pantanal biomes of Brazil. Between February 2000 and January 2010, blood samples were collected from 30 jaguars, 129 domestic dogs ( Canis lupus familiaris), and 22 domestic cats ( Felis catus ) for molecular tests. All of the jaguars from the Pantanal (n = 22) and Cerrado (n = 4) and 3 of 4 jaguars from the Amazon were positive for Hepatozoon spp. Domestic dogs (62.8%) and cats (31.8%) were also positive for the agent. Hepatozoon nucleotide sequences from jaguars and domestic cats grouped with other Hepatozoon felis, whereas Hepatozoon from domestic dogs showed high similarity to Hepatozoon canis. Different species of Amblyomma were identified as parasitizing the jaguars and may act as vectors for Hepatozoon spp. Jaguars from the 3 sites were healthy and did not seem to be threatened by the hemoparasite within its population or environments. Most likely, jaguars play an important role in the maintenance of Hepatozoon spp. in nature.

Exposure of Free-Ranging Wild Carnivores and Domestic Dogs to Canine Distemper Virus and Parvovirus in the Cerrado of Central Brazil

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

Canine distemper virus as a threat to wild tigers in Russia and across their range

Canine distemper virus (CDV) has recently been identified in populations of wild tigers in Russia and India. Tiger populations are generally too small to maintain CDV for long periods, but are at risk of infections arising from more abundant susceptible hosts that constitute a reservoir of infection. Because CDV is an additive mortality factor, it could represent a significant threat to small, isolated tiger populations. In Russia, CDV was associated with the deaths of tigers in 2004 and 2010, and was coincident with a localized decline of tigers in Sikhote-Alin Biosphere Zapovednik (from 25 tigers in 2008 to 9 in 2012). Habitat continuity with surrounding areas likely played an important role in promoting an ongoing recovery. We recommend steps be taken to assess the presence and the impact of CDV in all tiger range states, but should not detract focus away from the primary threats to tigers, which include habitat loss and fragmentation, poaching and retaliatory killing. Research priorities include: (i) recognition and diagnosis of clinical cases of CDV in tigers when they occur; and (ii) collection of baseline data on the health of wild tigers. CDV infection of individual tigers need not imply a conservation threat, and modeling should complement disease surveillance and targeted research to assess the potential impact to tiger populations across the range of ecosystems, population densities and climate extremes occupied by tigers. Describing the role of domestic and wild carnivores as contributors to a local CDV reservoir is an important precursor to considering control measures.

Canine Distemper Virus in Wild Felids of Costa Rica

Several highly infectious diseases can be transmitted through feces and cause elevated mortality among carnivore species. One such infectious agent, canine distemper virus (CDV; Paramyxoviridae: Morbillivirus), has been reported to affect wild carnivores, among them several felid species. We screened free-ranging and captive wild carnivores in Costa Rica for CDV. Between 2006 and 2012, we collected 306 fecal samples from 70 jaguars (Panther onca), 71 ocelots ( Leopardus pardalis ), five jaguarundis (Puma yaguaroundi), 105 pumas ( Puma concolor ), five margays ( Leopardus wiedii ), 23 coyotes ( Canis latrans ), and 27 undetermined Leopardus spp. We found CDV in six individuals: one captive jaguarundi (rescued in 2009), three free-ranging ocelots (samples collected in 2012), and two free-ranging pumas (samples collected in 2007). Phylogenetic analyses were performed using sequences of the phosphoprotein (P) gene. We provide evidence of CDV in wild carnivores in Costa Rica and sequence data from a Costa Rican CDV isolate, adding to the very few sequence data available for CDV isolates from wild Central American carnivores.

Serological Survey of Hantavirus in Inhabitants from Tropical and Subtropical Areas of Brazil

Brazil has reported more than 1,600 cases of hantavirus cardiopulmonary syndrome (HPS) since 1993, with a 39% rate of reported fatalities. Using a recombinant nucleocapsid protein of Araraquara virus, we performed ELISA to detect IgG antibodies against hantavirus in human sera. The aim of this study was to analyze hantavirus antibody levels in inhabitants from a tropical area (Amazon region) in Rondônia state and a subtropical (Atlantic Rain Forest) region in São Paulo state, Brazil. A total of 1,310 serum samples were obtained between 2003 and 2008 and tested by IgG-ELISA, and 82 samples (6.2%), of which 62 were from the tropical area (5.8%) and 20 from the subtropical area (8.3%), tested positive. Higher levels of hantavirus antibody were observed in inhabitants of the populous subtropical areas compared with those from the tropical areas in Brazil.

Prevalence and risk factors for viral exposure in rural dogs around protected areas of the Atlantic forest

BACKGROUND

Despite the crucial role of domestic dogs as reservoirs for zoonosis and some of the most threatening diseases for wild carnivores such as distemper and parvovirosis, little is known about the epidemiological features and the risk factors involved in pathogen exposure of dogs that live in human/wildlife interfaces and actually contacts wildlife. Through a cross-sectional serological approach and questionnaire survey, we assessed the prevalence along with individual and environment-associated risk factors for four important viral diseases of rural dogs living in households around six Atlantic Forest fragments in southeast Brazil.

RESULTS

Widespread exposure to canine parvovirus (97%), canine distemper virus (15%) and canine adenovirus (27%) was detected, but none for canine coronavirus. Dogs from small private reserves were more exposed to parvovirus and canine distemper virus than those from larger state parks. Exposure was associated with dog sex and age, lack of health care and the number of people in the households. Remarkably, factors linked to free-ranging behaviour of dogs were associated with the exposure for all pathogens detected.

CONCLUSIONS

According to identified associations, reducing viral pathogen exposure in dogs will require inhibiting dog's movements and access to nearby forests and villages and improving veterinary assistance. Promoting dog vaccination and population control through sterilization around protected areas is also necessary. The study provides support for preventive management actions aimed to protect the health of rural dogs, and consequently of Atlantic Forest's wild carnivores.

Cross-species transmission of canine distemper virus-an update

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

The V domain of dog PVRL4 (nectin-4) mediates canine distemper virus entry and virus cell-to-cell spread

The entry of canine distemper virus (CDV) is a multistep process that involves the attachment of CDV hemagglutinin (H) to its cellular receptor, followed by fusion between virus and cell membranes. Our laboratory recently identified PVRL4 (nectin-4) to be the epithelial receptor for measles and canine distemper viruses. In this study, we demonstrate that the V domain of PVRL4 is critical for CDV entry and virus cell-to-cell spread. Furthermore, four key amino acid residues within the V domain of dog PVRL4 and two within the CDV hemagglutinin were shown to be essential for receptor-mediated virus entry.

Canine distemper virus (CDV) in another big cat: should CDV be renamed carnivore distemper virus?

One of the greatest threats to the conservation of wild cat populations may be dogs or, at least, one of their viruses. Canine distemper virus (CDV), a single-stranded RNA virus in the Paramyxoviridae family and genus Morbillivirus, infects and causes disease in a variety of species, not just canids. An outbreak of CDV in wild lions in the Serengeti, Tanzania, in 1994 was a wake-up call for conservationists, as it demonstrated that an infectious disease could swiftly impact a previously healthy felid population. To understand how this virus causes disease in noncanid hosts, researchers have focused on specific mutations in the binding site of the CDV hemagglutinin gene. Now, Seimon et al. provide information on CDV in its latest feline victim, the endangered wild Amur tiger (Panthera tigris altaica) [T. A. Seimon et al., mBio 4(4):e00410-13, 2013, doi:10.1128/mBio.00410-13]. Their findings of CDV strains infecting tigers, in combination with recent information from other felids, paints a different picture, one in which CDV strains from a variety of geographic lineages and with a variety of amino acid residues in the hemagglutinin gene binding site can infect cats and cause disease. Although CDV has been known as a multihost disease since its discovery in domestic dogs in 1905, perhaps it is time to reconsider whether these noncanid species are not just incidental or "spillover" hosts but, rather, a normal part of the complex ecology of this infectious disease.

The fusion protein signal-peptide-coding region of canine distemper virus: a useful tool for phylogenetic reconstruction and lineage identification

Canine distemper virus (CDV; Paramyxoviridae, Morbillivirus) is the etiologic agent of a multisystemic infectious disease affecting all terrestrial carnivore families with high incidence and mortality in domestic dogs. Sequence analysis of the hemagglutinin (H) gene has been widely employed to characterize field strains, permitting the identification of nine CDV lineages worldwide. Recently, it has been established that the sequences of the fusion protein signal-peptide (Fsp) coding region are extremely variable, suggesting that analysis of its sequence might be useful for strain characterization studies. However, the divergence of Fsp sequences among worldwide strains and its phylogenetic resolution has not yet been evaluated. We constructed datasets containing the Fsp-coding region and H gene sequences of the same strains belonging to eight CDV lineages. Both datasets were used to evaluate their phylogenetic resolution. The phylogenetic analysis revealed that both datasets clustered the same strains into eight different branches, corresponding to CDV lineages. The inter-lineage amino acid divergence was fourfold greater for the Fsp peptide than for the H protein. The likelihood mapping revealed that both datasets display strong phylogenetic signals in the region of well-resolved topologies. These features indicate that Fsp-coding region sequence analysis is suitable for evolutionary studies as it allows for straightforward identification of CDV lineages.

Canine distemper spillover in domestic dogs from urban wildlife

Canine distemper virus (CDV) causes a major disease of domestic dogs that develops as a serious systemic infection in unvaccinated or improperly vaccinated dogs. Domesticated dogs are the main reservoir of CDV, a multihost pathogen. This virus of the genus Morbillivirus in the family Paramyxoviridae occurs in other carnivorous species including all members of the Canidae and Mustelidae families and in some members of the Procyonidae, Hyaenidae, Ursidae, and Viverridae families. Canine distemper also has been reported in the Felidae family and marine mammals. The spread and incidences of CDV epidemics in dogs and wildlife here and worldwide are increasing.