Canine Distemper Virus (CDV): an Emerging Threat to Nepal's Wildlife
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Applied Science and Technology Annals Vol.1, No.1 (2020); 149-154 ISSN: 2717-5014 (Print). Available online at www.recast.tu.edu.np DOI: https://doi.org/10.3126/asta.v1i1.30294 Thematic Opinion Canine Distemper Virus (CDV): an emerging threat to Nepal’s wildlife Roshan Babu Adhikari 1,2,5, Mina Shrestha 2,6, Ganesh Puri 3,7, Ganga Ram Regmi 2,4,8 and Tirth Raj Ghimire 1,9,* 1Animal Research Laboratory, Faculty of Science, Nepal Academy of Science and Technology (NAST), Khumaltar, Lalitpur, Nepal 2 Third Pole Conservancy, Bhaktapur-10, Pipeline, Nepal 3 Department of Forests, Ministry of Forests and Environment, Government of Nepal 4 Institute of Forestry, Tribhuvan University, Nepal 5 E-mail: [email protected], ORCID ID: 0000-0002-5876-667X 6 E-mail: [email protected], ORCID ID: 0000-0002-3996-0709 7 E-mail: [email protected], ORCID ID: 0000-0002-6382-4707 8 E-mail: [email protected], ORCID ID: 0000-0002-8392-5863 9 E-mail: [email protected], ORCID ID: 0000-0001-9952-1786 Received: May 15, 2020; Accepted: June 14, 2020; Published: June 25, 2020 Abstract: In this article, we have described the urgency of research on CDV in the domestic and feral dogs roaming in and around the protected areas of Nepal where the already threatened wildlife have been struggling for their existence from the immense anthropogenic pressures. Keywords: canine distemper; carnivores; conservation; feral dogs; mass extinction ;f/f+z g]kfndf dfgjåf/f pTkGg ckf/ rfkx?n] ubf{ b'n{e hgfj/x?n] klxn] b]lvg} cl:tTjsf] nflu ;+3if{ ul//x]sf 5g\ / : g]kfnsf] ;+/lIft If]q tyf pQm If]q jl/kl/ /x]sf 3/kfn'jf tyf lkm/Gt] s's'/x?df x'g] s]gfOg l8:6]Dk/ efO/; cg';Gwfgsf] h?/L /x]sf] s'/fsf] j0f{g of] n]vdf xfdLn] u/]sf 5f}+ . * Corresponding author, E-mail: [email protected]; Tel.: +977-1-5547715 © RECAST/TU 1. Introduction It is known that the government of Nepal has pathogens like viruses, bacteria, fungi, and parasites allocated millions of dollars in the conservation of (Ghimire et al., 2020). Principally, we consider that flora and fauna each year. The budget is mainly pathogens are one of the contributing factors in the spent on the projects that focus on population survey wildlife decline in the future; for instance, Canine and monitoring, awareness generation, training, Distemper Virus (CDV) should be recognized as a security, construction, relief aid, support to local critical microbe possessing the capability to lead people, seminars, meetings, and administrations. endangerment of both captive and wild animals. But, the budget has not been allocated to the research CDV (order: Mononegavirales, family: on wildlife-declining factors, for example, antibiotic Paramyxoviridae, subfamily: Paramyxovirinae, resistivity, pesticide poisoning, plant poisoning, and genus: Morbillivirus) is a pleomorphic virus 149 possessing a lipoprotein envelope and a single- America, Africa, and South America. Various stranded negative-sense RNA molecule (Zhang et al. laboratory techniques like neutralizing antibody tests 2017; Sykes 2014; https://talk.ictvonline.org/ictv- and histologic assays detected 100% positive cases reports/ictv_9th_report/negative-sense-rna-viruses- (Yoshikawa et al., 1989; Pardo et al., 2005), and 2011/w/negrna_viruses/199/paramyxoviridae, critically, this virus has been shown to result in Retrieved on: June 5, 2020). CDV is transmitted via 100% mortality in many animals (Pardo et al., 2005). oronasal contact with the virus in secretions or We used Arc map 10.2.1 (Redlands, CA) to prepare excretions like urine, blood, saliva, droplet nuclei, maps of CDV cases in the different continents and large particle aerosol from infected animals (Figure 1). We also used Excel 2007 Sheet to make a (Appel and Summers 1995; Sykes 2014). Therefore, graph of CDV cases according to the hosts' families sneezing, coughing, sharing of feed, and food and their habitat (Figure 2). A line graph was serving utensils with other animals may pose risks of prepared to show CDV cases and numbers of viral contamination and transmission. The virus publications at every eight years from 1956 onwards leads to systemic diseases in a variety of organs, (Figure 3). The reviews revealed that CDV cases such as in integumentary, gastrointestinal, were maximum in canidae family and wild animals, respiratory, and neurologic systems (Sykes 2014). It although they have been reported in a total of 15 can cause immunosuppression; that is why families. The cases were positive in captive, secondary infections by bacteria and protozoa may domestic, feral, and wild populations. While aid higher mortality of the hosts (Riley and Wilkes analyzing the numbers of published reports as well 2015; Beineke et al., 2015; Zhang et al., 2017). CDV as cases, they peaked only after 1987. Therefore, affects a wide range of host families, including CDV is one of the deadly viruses that can affect both ailuridae (red panda), canidae (dog, fox, raccoon wild and domestic animals globally. dog, wolf), cercopithecidae (crab-eating macaques, 3. Challenges to Nepalese wildlife Japanese macaques, and rhesus macaques), cervidae We hypothesize that the CDV, the poorly (sika deer), elephantidae (Asian elephant), felidae addressed threat, can result in a challenging problem (Amur leopard, domestic cat, jaguar, jaguarundi, to Nepalese wildlife. The hypothesis is supported by lion, lynx, ocelots, pumas, snow leopard, tiger), a few facts. For example, dogs, the potent reservoirs, hyaenidae (hyena), mephitidae (skunk), mustelidae transporters, or carrier hosts of CDV, are widely (badger, ferret, fisher, martes, mink, polecat, stone distributed all over the landscapes. Although they marten, weasel), myrmecophagidae (tamandu), can be asymptomatic, CDV can be transmitted in procyonidae (raccoon), phocidae (seal), suidae (wild their population (Sidhu et al., 2019). Besides, the boar), ursidae (bear, giant panda), tayassuidae CDV-infected dogs can also spread the diseases to (javelina), and vivirridae (binturong, palm civet) all the wildlife-proximity areas. In this context, the feral over the world. Critically, the virus is highly dogs, which usually share overlapping niches of susceptible to newly exposed or unvaccinated wildlife, can transmit the virus either directly via populations of various animals and contributes to saliva and respiratory droplets or indirectly via stool fatal consequences threatening their populations and urine. The CDV has already been indicated to (University of Leeds 2007; Kapil and Yeary 2011); cross the species barrier easily and can be thus, it indicates the need of basic research in virus transmitted from one species to another (Beineke et and its impacts on the animal population in a country al., 2015) and vice versa; for example, in Portugal, like Nepal where the study of diseases is usually CDV found in the wolves was transmitted from the neglected or ignored by experts and administration local domestic dogs (Muller et al., 2011), while a in policy levels. major outbreak of CDV in Danish farm mink 2. Patterns and distribution of CDV (Neovison vison) resulted from the wildlife We used the term 'Canine Distemper Virus' to see reservoirs like fox, raccoon dog, and ferrets the patterns and distribution of CDV in various hosts (Trebbien et al., 2014). One compelling case of the and searched the articles from Google Scholar, CDV positivity was reported in the wild and captive PubMed, and ResearchGate. The last search was macaques in China and Japan (Yoshikawa et al., done in June 2020. We selected and reviewed 80 1989; Sakai et al., 2008; Sun et al., 2009; Qiu et al., articles published in the journals from 1956 to 2019 2011). It may indicate that the animals closely (Supplementary file). The reviews were mainly contacting these primates are also susceptible to focused on a common name, scientific name, family, CDV transmission. In these contexts, Nepal might be order, taxonomic serial number (isit.gov), IUCN Red prone to CDV because dogs and macaques in city List, habitat, country, continent, and year of areas usually live closely with humans, especially in publications. We found that this disease was reported the temples, monasteries, and in 125 cases in 28 countries in Asia, Europe, North 150 Figure 1. Global Distribution of Canine Distemper Virus (CDV) cases. Viverridae Ursidae Captive Domestic Tayassuidae Suidae Feral Wild Procyonidae Phocidae Myrmecophagidae Mustelidae Mephitidae Hyaenidae Felidae Cervidae Cercopithecidae Canidae Ailuridae 0 5 10 15 20 25 30 35 40 45 50 Numbers of cases Figure 2. Distribution of CDV cases according to the hosts' family and their habitat. 151 80 No. of CDV positive cases 70 No. of articles published 60 50 40 30 20 10 0 Figure 3. Line graphs showing the CDV cases and numbers of publications at every eight years from 1956 onwards. a b c d Figure 4. Camera-trapped images in Manang, Annapurna Conservation Area. (a) Himalayan wolf (b) Feral dog (c) Snow leopard (d) Golden jackals. Photos by Tashi R Ghale/ Third Pole Conservancy. gompas. The transmission of CDV among wild and groups (Ng et al., 2019). The authors detected the domestic animals always has negative impacts on the CDV in asymptomatic domestic dogs in and around existing populations, particularly on the threatened the Annapurna Conservation Area (Ng et al., 2019), and endangered species (Berentsen et al., 2013). the protective home of several threatened species Therefore, the roles of macaques and feral dogs including snow leopards, wolves, Pallas’s cats, surviving and roaming in and around the protected foxes, and mustelids (Regmi et al., 2020, submitted areas like National Parks, Wildlife Reserves, and manuscript) (Figure 4). Therefore, we assume that Conservation areas cannot be ignored in threatening CDV might be transported by these suspected the wild fauna. The suspected case also can be vectors (dogs) to other susceptible animals in the evidenced by a previously published article by forest areas and finally, the infection reaches to the Debby Ng of the University of Tasmania and the top-level predators like snow leopards and wolves 152 which may lead to the local mass extinction of these Ethical approval: Not applicable.