Detection and sequence analysis of Canine morbillivirus in multiple species of the Mustelidae family

Geographical Distribution of Carnivore Hosts and Genotypes of Canine Distemper Virus (CDV) Worldwide: A Scoping Review and Spatial Meta-Analysis

Background: Emerging viral diseases are spreading to new geographic locations, influenced by human activities and climate change. Morbillivirus canis (also known as canine distemper virus, CDV), the etiological agent of CD, is distributed worldwide and shared between wild and domestic animals. Methods: A systematic review using MeSH terms was carried out from 1985 to 2024, focusing the search on studies (PubMed and WOS) that would detect CDV and sequence it in a known genotype in Carnivora hosts. Articles were reviewed by four researchers, and after quality assessment, we selected 160 published papers for data extraction, analysis, and spatial meta-analysis. Considering species studied, geographical location, and classified genotypes we identify 457 different individual studies (records) from which 332 records CDV was sequenced into a classifiable 17 main genotypes. Spatial meta-analysis was performed using QGIS, revealing distributions of animals in which a CDV lineage has been isolated; geographical lineages overlapping on different hosts have been measured as a density function. Results: CDV host species belonged to the suborder Caniformia (93.7%) into families such as Canidae (75.2%), Mustelidae (9.7%), and Procyonidae (7.6%). Suborder Feliformia (6.1%) showed wild Felidae (5.1%) as the most represented family. Samples used were brain (13.74%), lung (12.4%), blood (10.8%), and nasal-eye discharges (8.9%; 8.1%). Reverse transcription-PCR (RT-PCR) (60.34%) and real-time-quantitative PCR (RT-qPCR) (26.57%) detecting H gene (62%) were most used to detect viral ARN. On genotypes, Europe/South America-1 (27.4%), Europe-3/Artic (15.5%), Asia-1 (14.5%), America-1 (11.2%), Europe-2/European Wildlife and Africa (Africa-1 and Africa-2) (7.6%) were the most represented worldwide, being America-1 and Europe/South America-1 the most widely distributed around the world. Conclusions: The analysis showed the wide multihost capacity and diversity of CDV, with dog (Canis lupus familiaris) as the most frequent (40%) and red fox (Vulpes vulpes) (30.2%) as the main wild host. Most of the detected lineages can be detected in several wild host families, in addition to the dog, suggesting constant spillover phenomena in shared habitats at the domestic-wild interface. The most cosmopolitan lineages mirror the distribution routes of their hosts, showing that it is difficult to establish a CDV-fixed picture in an interconnected world.

Exposure to anticoagulant rodenticides in steppe polecat (Mustela eversmanii) and European polecat (Mustela putorius) in central Europe

Poisoning caused by coumarin-type anticoagulant rodenticides (ARs) stands as the predominant method for controlling rodents globally. ARs, through secondary poisoning, pose a significant threat to predators due to their lethal and sublethal effects. We examined the concentration of accumulated ARs in liver samples of mostly road-killed steppe polecats (Mustela eversmanii) and European polecats (M. putorius) collected throughout Hungary between 2005 and 2021. The steppe polecat samples were found mainly from Eastern Hungary, while European polecats from Western Hungary. We measured the concentration of six residues by HPLC-FLD. Our analysis revealed the presence of one first-generation and four second-generation ARs in 53% of the steppe polecat (36) and 39% of the European polecat (26) samples. In 17 samples we detected the presence of at least two AR compounds. Although we did not find significant variance in AR accumulation between the two species, steppe polecats displayed greater prevalence and maximum concentration of ARs, whereas European polecat samples exhibited a more diverse accumulation of these compounds. Brodifacoum and bromadiolone were the most prevalent ARs; the highest concentrations were 0.57 mg/kg and 0.33 mg/kg, respectively. The accumulation of ARs was positively correlated with human population density and negatively correlated with the extent of the more natural habitats in both species. To the best of our knowledge, this is the first study to demonstrate anticoagulant rodenticide exposure in steppe polecats globally, and for European polecats in Central European region. Although the extent of AR accumulation in European polecat in Hungary appears comparatively lower than in many other European countries, the issue of secondary poisoning remains a serious problem as these ARs intrude into food webs. Reduced and more prudent usage of pesticides would provide several benefits for wildlife, included humans. However, we advocate a prioritization of ecosystem services through the complete prohibition of the toxicants.

Snapshot study of canine distemper virus in Bangladesh with on-site PCR detection and nanopore sequencing

Canine distemper virus (CDV) is a highly contagious virus that affects domestic and wild animals, causing severe illness with high mortality rates. Rapid monitoring and sequencing can provide valuable information about circulating CDV strains, which may foster effective vaccination strategies and the successful integration of these into conservation programs. During two site visits in Bangladesh in 2023, we tested a mobile, deployable genomic surveillance setup to explore the genetic diversity and phylogenetic patterns of locally circulating CDV strains. We collected and analysed 355 oral swab samples from stray dogs in Rajshahi and Chattogram cities, Bangladesh. CDV-specific real-time RT-PCR was performed to screen the samples. Out of the 355 samples, 7.4% (10/135) from Rajshahi city and 0.9% (2/220) from Chattogram city tested positive for CDV. We applied a real-time RT-PCR assay and a pan-genotype CDV-specific amplicon-based Nanopore sequencing technology to obtain the near-completes. Five near-complete genome sequences were generated, with phylogenetic relation to the India-1/Asia-5 lineage previously identified in India. This is the first study to provide genomic data on CDV in Bangladesh and the first demonstration of a mobile laboratory setup as a powerful tool in rapid genomic surveillance and risk assessment for CDV in low resource regions.

Study of Canine Distemper Virus Presence in Catalonia's Wild Carnivores through H Gene Amplification and Sequencing

Canine distemper virus (CDV) is recognised worldwide as an important pathogen in both domestic and wild carnivores. Few data are available on its impact and spread on the wildlife/wildlife-domestic animal-environment interface. This study, aimed at developing a conservation-oriented control strategy, analysed 89 sick or deceased animals from 2019 to 2023 at the Wildlife Rehabilitation Centre in Torreferrussa. RT-PCR and sequencing of the partial H gene were used to detect and analyse CDV in tissues. The total positive percentage was 20.22% (18/89), comprising 13 red foxes (44.8%), 4 European badgers (28.6%), and 1 American mink (4.5%), while 24 Eurasian otters tested negative. Phylogenetic analysis indicated that all of the CDV strains belong to the European lineage. Geographically distant individuals and different species shared the same viral strain, suggesting a strong capacity of CDV for interspecies and long-distance transmission. This calls for further research, particularly focusing on potential impacts of CDV on endangered carnivores.