Transmission ecology of canine parvovirus in a multi-host, multi-pathogen system

Protoparvovirus carnivoran 1 infection of golden jackals Canis aureus in Serbia

Parvoviruses are among the major animal pathogens that can cause considerable health disorders ranging from subclinical to lethal in domestic and wild animals. Golden jackal (Canis aureus), an expanding European species, is a reservoir of many pathogens, including vector-borne diseases and zoonoses. Given the importance of parvovirus infections in dogs and cats, this study aimed to unfold the virus prevalence and molecular characterisation in the golden jackal population in Serbia. The spleen samples from 68 hunted jackals during 2022/2023 were tested for the VP2-specific genome region of Protoparvovirus carnivoran 1 by PCR. BLAST analysis of partial VP2 sequences obtained from three animals (4.4%) revealed the highest similarity to Protoparvovirus carnivoran 1, genogroup Feline panleukopenia virus, which is the second report on FPV infection in jackals. Based on specific amino acid residues within partial VP2, the jackals' Protoparvovirus carnivoran 1 was also classified as FPV. One jackal's strain showed two synonymous mutations at positions 699 and 1167. Although species cross-transmission could not be established, jackals' health should be maintained by preventing the transmission of viruses to native species and vice versa. Although jackals are considered pests, their role as natural cleaners is of greater importance. Therefore, further monitoring of their health is needed to understand the influence of infectious diseases on population dynamics and to determine the relationship between domestic predators and jackals and the direction of cross-species transmission.

Fatal canine parvovirus type 2a and 2c infections in wild Chinese pangolins (Manis pentadactyla) in southern China

The Chinese pangolin (Manis pentadactyla) is a critically endangered scale-covered mammal belonging to the order Pholidota. Wild pangolins are notably susceptible to pathogen infection and are typically characterized by impoverished health. However, little is currently known regarding the viruses prevalent among pangolins. In this study, we report the detection of two subtypes of canine parvovirus type 2 (CPV-2), namely CPV-2a and CPV-2c, both of which caused severe diarrheal disease in two post-rescue pangolins with fatal consequences. As in CPV-2-infected dogs, intensive lesion of the mucosal layer of the small intestines is a prominent feature in infected pangolins. Moreover, the immunochemistry results demonstrated that CPV-2 antigens were distributed in the crypts of small intestine. Additionally, typical parvovirus-associated CPV-2 were detected after four passages in F81 cells, and typical parvovirus-like particles, approximately 20 nm in diameter, were observed in the cell supernatants. Phylogenetic analysis revealed that the VP2 viral protein sequences (GenBank accession number OP208805) isolated from one pangolin (termed P1) were classified as CPV-2c, with 99.8% identity to a CPV-2c strain (MN832850) isolated from a Taiwanese pangolin found in Taiwan Province. In contrast, VP2 sequences (#OP208806) obtained from the second pangolin (P2) were classified as CPV-2a, with 99.8% identity to a CPV-2a strain (KY386858) isolated from southern China. In this study, we thus confirmed the infection of pangolins with CPV-2c in mainland China and demonstrated that CPV-2a also can infect pangolins. Based on these findings, we recommend that further investigations should be conducted to establish the interspecies transmission of these viruses among wild pangolins, wild carnivores, and stray dogs.

Investigation of Carnivore protoparvovirus 1 and Amdoparvovirus infections in red fox populations of the Italian Dolomites

Members of the family Parvoviridae are well recognized infectious agents of companion, livestock and wild animals as well, whose relevance on production, health, welfare and conservation is often high. Nevertheless, the knowledge of their epidemiology in wild populations is scarce or fragmentary. In this study, the presence and features of two parvoviruses, Carnivore protoparvovirus 1 and Amdoparvovirus, were evaluated in the red fox population resident in the Dolomites area, Northern Italy, and compared with the scenario of other countries and Italian regions. Six out of 117 spleen samples (5.13%: 95CI: 1.91-10.83%) tested positive to Carnivore protoparvovirus 1 and were molecularly characterized as Canine parvovirus (CPV). Infection frequency was comparable with that observed in wild carnivore populations present in Southern Italian regions, although in that case, Feline parvovirus (FPV) was predominant. No evidence of infection-related clinical signs was reported and viral loads were invariably low, suggesting the subclinical nature of the infection, the persistent carrier status or the detection of traces of viral DNA. No samples tested positive to Amdoparvovirus genus-specific PCR. The present study provides the first evidence of CPV circulation in the Northern Italy fox population. Unfortunately, the inevitable convenience nature of the sampling prevents definitive conclusions. Therefore, a more coordinated and standardized approach should be applied, at least in neighbouring geographic areas, to study these viral infections and their relevance in wildlife.

Distribution and diversity of dog parvoviruses in wild, free-roaming and domestic canids of Newfoundland and Labrador, Canada

Some parvoviruses of carnivorans can infect multiple host species. Since many canine parvoviruses were only discovered recently, their host-range is still unexplored. We examined the host distribution and diversity of five dog parvoviruses in four canine populations from Newfoundland and Labrador, Canada, and investigated the potential for these viruses to cross the species barriers. Canine bocavirus 2 (CBoV-2) and the minute virus of canines were detected in stool from free-roaming dogs from Labrador (5/48 [10.4%] and 3/48 [6.3%], respectively) and two different CBoV-2 variants were identified. Canine bufavirus was identified in stool from free-roaming dogs (1/48, 2.1%) and foxes (3/80, 3.8%) from Labrador, but two different variants were observed in the two host species. The variant found in foxes was highly divergent from previously identified strains. Two cachavirus 1 variants, genetically similar to those circulating in other Canadian wildlife, were found in spleens from Newfoundland coyotes (3/87, 3.5%). Canine parvovirus type 2 (CPV-2) was found in stool from free-roaming dogs from Labrador (2/48, 4.2%) and in spleens from Newfoundland coyotes (3/87, 3.5%). Comparing CPV-2 sequences from these hosts to those retrieved from local symptomatic domestic dogs revealed the presence of a highly heterogeneous viral population as detected strains belonged to five different clades. The close relationship between CPV-2a strains from a dog and a coyote suggests the occurrence of viral transfer between wild and domestic canids. The identification of highly related strains with a similar molecular signature characteristic of older CPV-2 strains in free-roaming and domestic dogs suggests a probable common ancestry and that older CPV-2 strains, which have not been identified in dogs since the 1990s, persist in this part of Canada. Follow-up studies should evaluate samples from a larger number of animals and host species to extensively investigate the possible occurrence of cross-species transmission for recently discovered parvoviruses.

Canine parvovirus-2: An Emerging Threat to Young Pets

Canine parvovirus-2 (CPV-2) is a highly contagious and key enteropathogen affecting the canine population around the globe by causing canine parvoviral enteritis (CPVE) and vomition. CPVE is one of the the leading causes of morbidity and mortality in puppies and young dogs. Over the years, five distinct antigenic variants of CPV-2, namely CPV-2a, CPV-2b, new CPV-2a, new CPV-2b, and CPV-2c, have emerged throughout the world. CPV-2 infects a diverse range of wild animals, and the newer variants of CPV-2 have expanded their host range to include felines. Despite the availability of highly specific diagnostics and efficacious vaccines, CPV-2 outbreaks have been reported globally due to the emergence of newer antigenic variants, expansion of the viral host range, and vaccination failures. The present chapter describes the latest information pertaining to virus properties and replication, disease manifestations in animals, and an additional recent updates on diagnostic, prevention and control strategies of CPV-2.

The Importance of Accurate Host Species Identification in the Framework of Rabies Surveillance, Control and Elimination

Accurate host identification is paramount to understand disease epidemiology and to apply appropriate control measures. This is especially important for multi-host pathogens such as the rabies virus, a major and almost invariably fatal zoonosis that has mobilized unanimous engagement at an international level towards the final goal of zero human deaths due to canine rabies. Currently, diagnostic laboratories implement a standardized identification using taxonomic keys. However, this method is challenged by high and undiscovered biodiversity, decomposition of carcasses and subjective misevaluation, as has been attested to by findings from a cohort of 242 archived specimens collected across Sub-Saharan Africa and submitted for rabies diagnosis. We applied two simple and cheap methods targeting the Cytochrome b and Cytochrome c oxidase subunit I to confirm the initial classification. We therefore suggest prioritizing a standardized protocol that includes, as a first step, the implementation of taxonomic keys at a family or subfamily level, followed by the molecular characterization of the host species.

A Three-Year Biocrime Sanitary Surveillance on Illegally Imported Companion Animals

The illegal trade of companion animals in the European Union poses several legal, ethical and health issues to the entire community. In the framework of the Biocrime Interreg project between Italy and Austria, we surveyed puppies and kittens confiscated at the borders to identify the most frequent pathogens associated with (i) the risk of spread within the shelter, (ii) the development of fatal disease and (iii) the zoonotic potential. From January 2018 to December 2020, we examined a total of 613 puppies and 62 kittens coming from 44 requisitions. Feces, skin specimens and blood sera from confiscated animals were tested to verify the presence of major infections and to assess the rabies post-vaccination immunity. Out of the total of individuals under investigation, necropsies and laboratory investigations were also performed on 79 puppies and three kittens that had died during the observation period. Results indicated a high prevalence of Canine Parvovirus (CPV) and Giardia spp. infections, CPV as the most likely cause of fatal gastroenteritis in puppies and Salmonella and Microsporum canis as major zoonotic pathogens. Conversely, both extended spectrum beta lactamases Escherichia coli and methicillin resistant Staphylococcus pseudintermedius strains as rare findings. Results highlighted that illegal animal trade could expose the human population to potential zoonotic risk and naïve animal population to potentially disrupting epidemic waves, both of these issues being largely underestimated when buying companion animals.

Molecular Characteristics of Carnivore protoparvovirus 1 with High Sequence Similarity between Wild and Domestic Carnivores in Taiwan

Carnivore protoparvovirus 1 (CPPV-1) is a DNA virus causing gastrointestinal disease and immunosuppression in various terrestrial carnivores. Domestic dogs and cats are considered the primary CPPV-1 reservoirs. The habitat overlap of wild carnivores and free-roaming dogs increases the threat of CPPV-1 transmission between them. This study explored the CPPV-1 distribution among wild carnivores in Taiwan through PCR screening and compared the partial capsid protein (VP2) gene sequences from wild and domestic carnivores. In total, 181 samples were collected from 32 masked palm civets (Paguma larvata), 63 Chinese ferret badgers (Melogale moschata), and 86 crab-eating mongooses (Herpestes urva), from 2015 to 2019 were screened for CPPV-1. The average prevalence of CPPV-1 was 17.7% (32/181), with the highest prevalence in masked palm civets (37.5%). In addition, a masked palm civet was coinfected with two CPPV-1 strains. Among the 33 partial VP2 gene sequences, 23 were identical to the sequences amplified from domestic dogs and cats in Asia, and the remaining 10 were identified for the first time. This study supported the circulation of CPPV-1 strains with the same genomic features as domestic carnivores that are also in wild carnivores from the same environment in Taiwan by molecular data. Therefore, further population control and health management of free-roaming domestic carnivores are recommended.

Risk and Environmental Factors Associated with the Presence of Canine Parvovirus Type 2 in Diarrheic Dogs from Thessaly, Central Greece

Canine parvovirus type 2 (CPV-2) primarily infects dogs, which are the main host reservoir, causing severe gastrointestinal disease associated with immunosuppression. The present study was conducted in Thessaly, Greece and aimed to identify risk and environmental factors associated with CPV-2 infection in diarrheic dogs. Fecal samples were collected from 116 dogs presenting diarrhea and were tested by polymerase chain reaction (PCR) for the presence of CPV-2 DNA. Supplementary data regarding clinical symptoms, individual features, management factors and medical history were also gathered for each animal during clinical evaluation. Sixty-eight diarrheic dogs were found to be positive for the virus DNA in their feces. Statistical analysis revealed that CPV-2 DNA was less likely to be detected in senior dogs, while working dogs, namely hounds and shepherds, had higher odds to be positive for the virus. Livestock density and land uses, specifically the categories of discontinuous urban fabric and of human population density, were identified as significant environmental parameters associated with CPV-2 infection by using Geographical Information System (GIS) together with the Ecological Niche Model (ENM). This is the first description of the environmental variables associated with the presence of CPV-2 DNA in dogs’ feces in Greece.

Adding Nuance to Our Understanding of Dog-Wildlife Interactions and the Need for Management

The interactions of dogs and wildlife are receiving increasing attention across the globe. Evidence suggests that dogs can negatively affect wildlife in a variety of ways, including through the risk of predation, by hybridizing with other Canis species, by acting as a reservoir or vector of pathogens, and by competing with wildlife for resources. A multitude of observations and case studies for each of these interactions has led to calls to prioritize increased management of dogs, for instance, through population reduction, vaccination, movement restrictions, and enhanced care of the dogs themselves. Here, I argue that while the risks that dogs present to wildlife are real, they vary in their importance across the globe. Furthermore, often the approaches used to address these risks are championed without a full understanding of the likelihood of success given the necessary spatial scale of management, the availability of alternative management approaches, and the role dogs play in societies. For instance, culling, vaccination, and animal husbandry approaches in reducing the impacts of dogs on wildlife sometimes fail to recognize that local human populations actively recruit replacement dogs, that vaccination often fails to reach levels necessary for herd immunity, and that enhanced dog husbandry may have indirect impacts on wildlife by requiring environmentally impactful activities. I suggest there is a need for attention not only to identify the impacts of dogs but also to determine where and when such interactions with wildlife are problematic and the likelihood of success for any proposed management approach. The impacts of dogs should be mediated in a context-specific manner that accounts for factors such as the local density of dogs, the susceptibility of local wildlife populations to the risks that dog populations may represent, and the local societal norms that underpin how dogs might be managed.

First report of canine parvovirus molecular detection in Bangladesh

Background and Aim:

Canine parvovirus (CPV) is the most important cause of mortality in dogs in many parts of the world. Clinical cases exhibit characteristic signs, including foul-smelling bloody diarrhea, vomiting, fever, and dehydration. This study assessed field and vaccine variants of parvovirus in the Chattogram metropolitan area, Bangladesh. The investigation also aimed to identify risk factors for this disease. This research is the first to identify the presence of CPV in Bangladesh through molecular examination.

Materials and Methods:

From October to December 2019, a total of 100 dogs were included in the study. Rectal swabs were taken from all dogs. Twenty dogs showed clinical signs of parvovirus. All clinically affected animals along with 20 randomly selected healthy dogs were tested using amplification refractory mutation system (ARMS)-polymerase chain reaction (PCR) to identify variants from the samples. Logistic regression model analysis was performed to determine the possible risk factors for CPV.

Results:

ARMS-PCR showed the presence of all three variants, CPV2a, CPV2b, and CPV2c, in clinically ill dogs, and vaccines available in the study area showed either CPV2a or CPV2b strain. The CPV2c variants showed a higher incidence than the other variants. All apparently healthy animals tested were molecularly negative. Multivariable logistic regression model (generalized linear mixed model) indicated that exotic breeds were 3.83 times more likely to be infected by CPV than local breeds. Furthermore, dogs reared in semi-intensive and extensive management systems were 3.64 and 3.79 times more likely to be infected, respectively, than those reared in an intensive management system.

Conclusion:

These findings provide practitioners and pet owners information on the occurrence of different variants and help design effective prevention strategies for CPV infection.

Domestic Dogs and Wild Foxes Interactions in a Wildlife-Domestic Interface of North-Central Chile: Implications for Multi-Host Pathogen Transmission

Domestic dogs (Canis familiaris) often cohabite at interfaces shared by humans and wildlife, interacting with wild canids as predators, prey, competitors and reservoirs of several multi-host pathogens, such as canid-borne micro and macro parasites that could impact on wildlife, livestock and public health. However, spatio-temporal patterns of indirect interactions as promoters of pathogen transfer between domestic and wild canids are largely unknown. In this study, we used camera traps to describe the activity patterns and habitat use of dogs, chilla (Lycalopex griseus) and culpeo (Lycalopex culpaeus) foxes and identify the local-scale factors that may affect the frequency of dog-fox interactions through an anthropization gradient of the Coquimbo region, Chile. We assessed local-scale variables that may predict the number of interactions between dogs and foxes, and compared the time interval between dog-culpeo and dog-chilla interactions. Our findings suggested that closeness to urbanized zones predicts the frequency of indirect interactions between dogs and foxes. We found higher number of dog-fox interactions (60 interactions) at a periurban site adjacent to two coastal towns (Tongoy and Guanaqueros), compared to other two more undisturbed sites (12 interactions) increasingly distanced from urbanized areas. We showed that dogs interacted more frequently with chilla foxes (57 interactions) than with culpeo foxes (15 interactions), and the first interaction type occurred almost exclusively at the periurban site, where dogs and chillas were more frequently detected than in the other sites. We detected a marked temporal segregation between dogs and foxes, but dog-chilla interactions resulted in shorter time intervals (2.5 median days) compared to dog-culpeo interactions (7.6 median days), suggesting a higher potential risk of pathogen spillover between the first species pairing. Based on previous studies, we suggest periurban zones may constitute a potential focus of pathogen exposure between dog and fox populations in the study area. Our research contributes to improving the knowledge on the spatio-temporal patterns of interspecific contact between invasive and native carnivores within the context of multi-host pathogen dynamics. Our outcomes will inform theoretical epidemiological models designed to predict and minimize the contact risk between domestic and threatened species, guiding effective control strategies at the wildlife-domestic interface.

A review of mechanistic models of viral dynamics in bat reservoirs for zoonotic disease

The emergence of SARS-CoV-2, a coronavirus with suspected bat origins, highlights a critical need for heightened understanding of the mechanisms by which bats maintain potentially zoonotic viruses at the population level and transmit these pathogens across species. We review mechanistic models, which test hypotheses of the transmission dynamics that underpin viral maintenance in bat systems. A search of the literature identified only twenty-five mechanistic models of bat-virus systems published to date, derived from twenty-three original studies. Most models focused on rabies and related lyssaviruses (eleven), followed by Ebola-like filoviruses (seven), Hendra and Nipah-like henipaviruses (five), and coronaviruses (two). The vast majority of studies has modelled bat virus transmission dynamics at the population level, though a few nested within-host models of viral pathogenesis in population-level frameworks, and one study focused on purely within-host dynamics. Population-level studies described bat virus systems from every continent but Antarctica, though most were concentrated in North America and Africa; indeed, only one simulation model with no associated data was derived from an Asian bat-virus system. In fact, of the twenty-five models identified, only ten population-level models were fitted to data - emphasizing an overall dearth of empirically derived epidemiological inference in bat virus systems. Within the data fitted subset, the vast majority of models were fitted to serological data only, highlighting extensive uncertainty in our understanding of the transmission status of a wild bat. Here, we discuss similarities and differences in the approach and findings of previously published bat virus models and make recommendations for improvement in future work.

Circulation of diverse protoparvoviruses in wild carnivores, Italy

Protoparvovirus is a monophyletic viral genus that includes the species Carnivore protoparvovirus-1 infecting domestic and wild carnivores. In this paper, the results of an epidemiological survey for Carnivore protoparvovirus-1 in wild carnivores in Italy are reported. Overall, 34 (11.4%) out of 297 tested animals were positive for Carnivore protoparvovirus-1, but the frequency of detection was much higher in intestine (54%) than in spleen samples (2.8%), thus suggesting that the intestine is the best sample to collect from wild animals for parvovirus detection. Feline panleukopenia virus (FPV) was detected in red foxes (Vulpes vulpes) (2.8%, 7/252) and Eurasian badgers (Meles meles) (10%, 1/10), whilst canine parvovirus (CPV) was found in wolves (54.3%, 19/35), Eurasian badgers (60%, 6/10) and one beech marten (Martes foina) (100%, 1/1), with more than one parvovirus type detected in some animals. Protoparvoviral DNA sequences from this study were found to be related to CPV/FPV strains detected in Asia and Europe, displaying some amino acid changes in the main capsid protein VP2 in comparison with other parvovirus strains from wildlife. In particular, the two most common mutations were Ile418Thr and Ala371Gly, which were observed in 6/12 (50%) and 5/12 (41.7%) of the CPV sequences from this study. Continuous surveillance for parvoviruses in wild carnivores and genetic analysis of the detected strains may help obtain new insight into the role of these animals in the evolution and epidemiology of carnivore parvoviruses.

Domestic dog origin of Carnivore Protoparvovirus 1 infection in a rescued free-ranging guiña (Leopardus guigna) in Chile

Carnivore protoparvovirus 1 is one of the most important pathogens affecting both wild and domestic carnivores. Here, we reported the genetic characterization of canine parvovirus (CPV-2) strains from a rescued guiña (Leopardus guigna) and domestic dogs from Chile. Guiña strain was classified as CPV-2c, and phylogenetic analysis of the complete coding genome showed that the guiña CPV-2c strain shares a recent common ancestor with Chilean domestic dogs' strains. These viruses showed >99% identity and exhibited three changes in the NS1 protein (V596A, E661K and L582F). This is the first detection and genetic characterization of CPV-2c infection in guiña worldwide, and one of the few comparative studies that show the source of infection was domestic dogs. The current findings highlight the fact that guiña is a susceptible species to protoparvovirus infection and that domestic dogs represent an important threat to its conservation. The CPV-2 cross-species transmission between domestic dogs and guiña should be taken into account for protection programmes of this endangered species.

Phylogenetic and Geospatial Evidence of Canine Parvovirus Transmission between Wild Dogs and Domestic Dogs at the Urban Fringe in Australia

Canine parvovirus (CPV) is an important cause of disease in domestic dogs. Sporadic cases and outbreaks occur across Australia and worldwide and are associated with high morbidity and mortality. Whether transmission of CPV occurs between owned dogs and populations of wild dogs, including Canis familiaris, Canis lupus dingo and hybrids, is not known. To investigate the role of wild dogs in CPV epidemiology in Australia, PCR was used to detect CPV DNA in tissue from wild dogs culled in the peri-urban regions of two Australian states, between August 2012 and May 2015. CPV DNA was detected in 4.7% (8/170). There was a strong geospatial association between wild-dog CPV infections and domestic-dog CPV cases reported to a national disease surveillance system between 2009 and 2015. Postcodes in which wild dogs tested positive for CPV were 8.63 times more likely to also have domestic-dog cases reported than postcodes in which wild dogs tested negative (p = 0.0332). Phylogenetic analysis of CPV VP2 sequences from wild dogs showed they were all CPV-2a variants characterized by a novel amino acid mutation (21-Ala) recently identified in CPV isolates from owned dogs in Australia with parvoviral enteritis. Wild-dog CPV VP2 sequences were compared to those from owned domestic dogs in Australia. For one domestic-dog case located approximately 10 km from a wild-dog capture location, and reported 3.5 years after the nearest wild dog was sampled, the virus was demonstrated to have a closely related common ancestor. This study provides phylogenetic and geospatial evidence of CPV transmission between wild and domestic dogs in Australia.

A Decade of Treatment of Canine Parvovirus in an Animal Shelter: A Retrospective Study

Here, we present 11.5 years of monthly treatment statistics showing an overall intake of 5127 infected dogs between June 2008 and December 2019, as well as more detailed datasets from more recent, less protracted time periods for the examination of mortality risk, seasonality, and resource requirements in the mass treatment of canine parvovirus (CPV) in a private animal shelter. The total survival rate of animals during the study period was 86.6% (n = 4438/5127 dogs survived) with the probability of survival increasing to 96.7% after five days of treatment (with 80% of fatalities occurring in that period). A distinct parvovirus season peaking in May and June and troughing in August, September, December, and January was observed, which could have contributed as much as 41 animals peak-to-trough in the monthly population (with a potential, smaller season occurring in October). Low-weight and male animals were at higher risk for death, whereas age was not a significant contributing factor. Treatment time averaged 9.03 h of total care during a seven-day median treatment duration. These findings, taken together, demonstrate that canine parvovirus can be successfully treated in a sustainable manner within a shelter setting using a largely volunteer workforce.

Ecology and Infection Dynamics of Multi-Host Amdoparvoviral and Protoparvoviral Carnivore Pathogens

Amdoparvovirus and Protoparvovirus are monophyletic viral genera that infect carnivores. We performed surveillance for and sequence analyses of parvoviruses in mustelids in insular British Columbia to investigate parvoviral maintenance and cross-species transmission among wildlife. Overall, 19.1% (49/256) of the tested animals were parvovirus-positive. Aleutian mink disease virus (AMDV) was more prevalent in mink (41.6%, 32/77) than martens (3.1%, 4/130), feline panleukopenia virus (FPV) was more prevalent in otters (27.3%, 6/22) than mink (5.2%, 4/77) or martens (2.3%, 3/130), and canine parvovirus 2 (CPV-2) was found in one mink, one otter, and zero ermines (N = 27). Viruses were endemic and bottleneck events, founder effects, and genetic drift generated regional lineages. We identified two local closely related AMDV lineages, one CPV-2 lineage, and five FPV lineages. Highly similar viruses were identified in different hosts, demonstrating cross-species transmission. The likelihood for cross-species transmission differed among viruses and some species likely represented dead-end spillover hosts. We suggest that there are principal maintenance hosts (otters for FPV, raccoons for CPV-2/FPV, mink for AMDV) that enable viral persistence and serve as sources for other susceptible species. In this multi-host system, viral and host factors affect viral persistence and distribution, shaping parvoviral ecology and evolution, with implications for insular carnivore conservation.

Fatal canine parvovirus-2 (CPV-2) infection in a rescued free-ranging Taiwanese pangolin (Manis pentadactyla pentadactyla)

Carnivore protoparvovirus 1 includes feline parvovirus (FPV), variants of canine parvovirus-2 (CPV-2), mink enteritis virus, and raccoon parvovirus, important pathogens affecting both wild and domestic carnivores. In this report, we described a fatal CPV-2 infection in a rescued Taiwanese pangolin, which provides the first evidence of CPV-2 infection in a non-carnivore. Post-rescue, the Taiwanese pangolin died from complications resulting from a severe panleucocytopenia and bloody diarrhoea. A full autopsy was performed and microscopic examination of the tissues revealed ulcerative, necrotizing, and haemorrhagic glossitis, esophagitis and enteritis. The results of transmission electronic microscopy, polymerase chain reaction and in situ hybridization provided confirmatory evidence that the lesions in the tongue, oesophagus and intestine were associated with a protoparvovirus. Phylogenetic comparison of the whole VP2 gene from the current pangolin protoparvovirus strain showed close clustering with the CPV-2c strains from domestic dogs in Taiwan, China and Singapore. The amino acid sequence of the pangolin protoparvovirus showed 100% identity to the CPV-2c strains from domestic dogs in China, Italy, and Singapore. The current findings highlight that pangolins are susceptible to protoparvoviruses. The potential of cross-species transmission of protoparvoviruses between Carnivora and Pholidota should be considered when housing pangolins in close proximity to carnivores and adopting strict biosecurity measures to avoid cross-species transmission in rescue facilities and zoos.

Fluorescent biomarkers demonstrate prospects for spreadable vaccines to control disease transmission in wild bats

Vaccines that autonomously transfer among individuals have been proposed as a strategy to control infectious diseases within inaccessible wildlife populations. However, rates of vaccine spread and epidemiological efficacy in real-world systems remain elusive. Here, we investigate whether topical vaccines that transfer among individuals through social contacts can control vampire bat rabies-a medically and economically important zoonosis in Latin America. Field experiments in three Peruvian bat colonies, which used fluorescent biomarkers as a proxy for the bat-to-bat transfer and ingestion of an oral vaccine, revealed that vaccine transfer would increase population-level immunity up to 2.6 times beyond the same effort using conventional, non-spreadable vaccines. Mathematical models showed that observed levels of vaccine transfer would reduce the probability, size and duration of rabies outbreaks, even at low but realistically achievable levels of vaccine application. Models further predicted that existing vaccines provide substantial advantages over culling bats-the policy currently implemented in North, Central and South America. Linking field studies with biomarkers to mathematical models can inform how spreadable vaccines may combat pathogens of health and conservation concern before costly investments in vaccine design and testing.

Interaction of a Densovirus with Glycans of the Peritrophic Matrix Mediates Oral Infection of the Lepidopteran Pest Spodoptera frugiperda

The success of oral infection by viruses depends on their capacity to overcome the gut epithelial barrier of their host to crossing over apical, mucous extracellular matrices. As orally transmitted viruses, densoviruses, are also challenged by the complexity of the insect gut barriers, more specifically by the chitinous peritrophic matrix, that lines and protects the midgut epithelium; how capsids stick to and cross these barriers to reach their final cell destination where replication goes has been poorly studied in insects. Here, we analyzed the early interaction of the Junonia coenia densovirus (JcDV) with the midgut barriers of caterpillars from the pest Spodoptera frugiperda. Using combination of imaging, biochemical, proteomic and transcriptomic analyses, we examined in vitro, ex vivo and in vivo the early interaction of the capsids with the peritrophic matrix and the consequence of early oral infection on the overall gut function. We show that the JcDV particle rapidly adheres to the peritrophic matrix through interaction with different glycans including chitin and glycoproteins, and that these interactions are necessary for oral infection. Proteomic analyses of JcDV binding proteins of the peritrophic matrix revealed mucins and non-mucins proteins including enzymes already known to act as receptors for several insect pathogens. In addition, we show that JcDV early infection results in an arrest of N-Acetylglucosamine secretion and a disruption in the integrity of the peritrophic matrix, which may help viral particles to pass through. Finally, JcDV early infection induces changes in midgut genes expression favoring an increased metabolism including an increased translational activity. These dysregulations probably participate to the overall dysfunction of the gut barrier in the early steps of viral pathogenesis. A better understanding of early steps of densovirus infection process is crucial to build biocontrol strategies against major insect pests.

How to make more from exposure data? An integrated machine learning pipeline to predict pathogen exposure

Predicting infectious disease dynamics is a central challenge in disease ecology. Models that can assess which individuals are most at risk of being exposed to a pathogen not only provide valuable insights into disease transmission and dynamics but can also guide management interventions. Constructing such models for wild animal populations, however, is particularly challenging; often only serological data are available on a subset of individuals and nonlinear relationships between variables are common. Here we provide a guide to the latest advances in statistical machine learning to construct pathogen-risk models that automatically incorporate complex nonlinear relationships with minimal statistical assumptions from ecological data with missing data. Our approach compares multiple machine learning algorithms in a unified environment to find the model with the best predictive performance and uses game theory to better interpret results. We apply this framework on two major pathogens that infect African lions: canine distemper virus (CDV) and feline parvovirus. Our modelling approach provided enhanced predictive performance compared to more traditional approaches, as well as new insights into disease risks in a wild population. We were able to efficiently capture and visualize strong nonlinear patterns, as well as model complex interactions between variables in shaping exposure risk from CDV and feline parvovirus. For example, we found that lions were more likely to be exposed to CDV at a young age but only in low rainfall years. When combined with our data calibration approach, our framework helped us to answer questions about risk of pathogen exposure that are difficult to address with previous methods. Our framework not only has the potential to aid in predicting disease risk in animal populations, but also can be used to build robust predictive models suitable for other ecological applications such as modelling species distribution or diversity patterns.

Carnivore Parvovirus Ecology in the Serengeti Ecosystem: Vaccine Strains Circulating and New Host Species Identified

Carnivore parvoviruses infect wild and domestic carnivores, and cross-species transmission is believed to occur. However, viral dynamics are not well understood, nor are the consequences for wild carnivore populations of the introduction of new strains into wild ecosystems. To clarify the ecology of these viruses in a multihost system such as the Serengeti ecosystem and identify potential threats for wildlife conservation, we analyzed, through real-time PCR, 152 samples belonging to 14 wild carnivore species and 62 samples from healthy domestic dogs. We detected parvovirus DNA in several wildlife tissues. Of the wild carnivore and domestic dog samples tested, 13% and 43%, respectively, were positive for carnivore parvovirus infection, but little evidence of transmission between the wild and domestic carnivores was detected. Instead, we describe two different epidemiological scenarios with separate routes of transmission: first, an endemic feline parvovirus (FPV) route of transmission maintained by wild carnivores inside the Serengeti National Park (SNP) and, second, a canine parvovirus (CPV) route of transmission among domestic dogs living around the periphery of the SNP. Twelve FPV sequences were characterized; new host-virus associations involving wild dogs, jackals, and hyenas were discovered; and our results suggest that mutations in the fragment of the vp2 gene were not required for infection of different carnivore species. In domestic dogs, 6 sequences belonged to the CPV-2a strain, while 11 belonged to the CPV-2 vaccine-derived strain. This is the first description of a vaccine-derived parvovirus strain being transmitted naturally.IMPORTANCE Carnivore parvoviruses are widespread among wild and domestic carnivores, which are vulnerable to severe disease under certain circumstances. This study furthers the understanding of carnivore parvovirus epidemiology, suggesting that feline parvoviruses are endemic in wild carnivores in the Serengeti National Park (SNP), with new host species identified, and that canine parvoviruses are present in the dog population living around the SNP. Little evidence of transmission of canine parvoviruses into wild carnivore species was found; however, the detection of vaccine-derived virus (described here for the first time to be circulating naturally in domestic dogs) highlights the importance of performing epidemiological research in the region.

Carnivore Parvovirus Ecology in the Serengeti Ecosystem: Vaccine Strains Circulating and New Host Species Identified

Carnivore parvoviruses infect wild and domestic carnivores, and cross-species transmission is believed to occur. However, viral dynamics are not well understood, nor are the consequences for wild carnivore populations of the introduction of new strains into wild ecosystems. To clarify the ecology of these viruses in a multihost system such as the Serengeti ecosystem and identify potential threats for wildlife conservation, we analyzed, through real-time PCR, 152 samples belonging to 14 wild carnivore species and 62 samples from healthy domestic dogs. We detected parvovirus DNA in several wildlife tissues. Of the wild carnivore and domestic dog samples tested, 13% and 43%, respectively, were positive for carnivore parvovirus infection, but little evidence of transmission between the wild and domestic carnivores was detected. Instead, we describe two different epidemiological scenarios with separate routes of transmission: first, an endemic feline parvovirus (FPV) route of transmission maintained by wild carnivores inside the Serengeti National Park (SNP) and, second, a canine parvovirus (CPV) route of transmission among domestic dogs living around the periphery of the SNP. Twelve FPV sequences were characterized; new host-virus associations involving wild dogs, jackals, and hyenas were discovered; and our results suggest that mutations in the fragment of the vp2 gene were not required for infection of different carnivore species. In domestic dogs, 6 sequences belonged to the CPV-2a strain, while 11 belonged to the CPV-2 vaccine-derived strain. This is the first description of a vaccine-derived parvovirus strain being transmitted naturally.IMPORTANCE Carnivore parvoviruses are widespread among wild and domestic carnivores, which are vulnerable to severe disease under certain circumstances. This study furthers the understanding of carnivore parvovirus epidemiology, suggesting that feline parvoviruses are endemic in wild carnivores in the Serengeti National Park (SNP), with new host species identified, and that canine parvoviruses are present in the dog population living around the SNP. Little evidence of transmission of canine parvoviruses into wild carnivore species was found; however, the detection of vaccine-derived virus (described here for the first time to be circulating naturally in domestic dogs) highlights the importance of performing epidemiological research in the region.