Trichuriasis in Selected Deer (Cervidae) Species: A Geographical Perspective

Trichuris spp. are endoparasites found in a wide range of mammalian species. Some of these host species include humans, non-human primates, dogs, cats, pigs, wild ruminants and domesticated ruminants. However, it had been noted that Trichuris are host specific, therefore the parasites that infects wild ruminant species may be transmitted to domesticated animals such as cattle, sheep and goat. Thus, the aim of this review was to identify species of Trichuris that parasitise deer species and to categorise the prevalence of this disease at various geographical locations. It must be noted that the prevalence and intensity of this parasite within deer species was low and rarely showed any signs of clinical disease. However, deer can be a source of infection to domesticated ruminants that may be housed in closed proximity. The review is divided into several sections based on the geographical location of the deer species. In summary, the review shows that most of the identification of various species of Trichuris in deer is based on morphological techniques. However, the use of molecular techniques in the identification of various species of Trichuris is more accurate. In closing, there is a need for more molecular investigations to be done in identifying the species of Trichuris that are present in deer living in the neo-tropical region.

Multivariate Abundance Analysis of Multi-Host/Multi-Parasite Lungworms in a Sympatric Wild Ruminant Population

In the analysis of a multi-host/multi-parasite system and its associated risk factors, it is particularly interesting to understand the natural dynamics among pathogens, their hosts, and the environment in wildlife populations. This analysis is particularly feasible in a scenario where multiple overlapping host populations are present in high densities, along with a complex community of parasites. We aimed to describe and analyze the naturally occurring lungworm polyparasitism in a wild ruminant community in Southeast Spain. The respiratory tracts of 250 specimens belonging to four different species (red deer, mouflon, Iberian ibex, and fallow deer) were studied. Almost half (48.0%) of the animals were infected with bronchopulmonary nematodes. Seven different nematodes were identified of which two genera (Protostrongylus spp. and Dictyocaulus spp.) and three additional species (Cystocaulus ocreatus, Muellerius capillaris, and Neostrongylus linearis) were recorded in at least two ruminants, with the mouflon as the commonest host. Our study shows a significant effect of host species and sampling area, plus a marginal effect of age, on parasite multivariate abundance at the host population level. Mouflon and adults of all hosts appear to carry the highest parasite load on average. From a spatial perspective, the highest parasite abundance was detected at the central part of the park.

Sarcoptic mange in wild ruminants in Spain: solving the epidemiological enigma using microsatellite markers

Background In Spain, sarcoptic mange was first described in native wildlife in 1987 in Cazorla Natural Park, causing the death of nearly 95% of the local native population of Iberian ibex (Capra pyrenaica). Since then, additional outbreaks have been identified in several populations of ibex and other wild ungulate species throughout the country. Although the first epizootic outbreak in wildlife was attributed to the introduction of an infected herd of domestic goats, the origin and the cause of its persistence remain unclear. The main aims of this study are to understand (i) the number of Sarcoptes scabiei “strains” circulating in wild ruminant populations in Spain, and (ii) the molecular epidemiological relationships between S. scabiei and its hosts. Methods Ten Sarcoptes microsatellite markers were used to characterize the genetic structure of 266 mites obtained from skin scrapings of 121 mangy wild ruminants between 2011 and 2019 from 11 areas in Spain. Results Seventy-three different alleles and 37 private alleles were detected. The results of this study show the existence of three genetic strains of S. scabiei in the wild ruminant populations investigated. While two genetic clusters of S. scabiei were host- and geography-related, one cluster included multi-host mites deriving from geographically distant populations. Conclusions The molecular epidemiological study of S. scabiei in wild ruminants in Spain indicates that the spreading and persistence of the parasite may be conditioned by host species community composition and the permissiveness of each host population/community to the circulation of individual “strains,” among other factors. Wildlife–livestock interactions and the role of human-driven introduction or trade of wild and domestic animals should be better investigated to prevent further spread of sarcoptic mange in as yet unaffected natural areas of the Iberian Peninsula.

Evaluation of the Baermann–Wetzel method for detecting lungworm larvae in wild ruminants from faecal samples

Lungworms can exert a negative impact on wild ruminant fitness; for this reason, the diagnosis of the associated diseases is an important prevention measure. The Baerman–Wetzel technique is the most usual method for the diagnosis of bronchopulmonary nematodes and is based on the active migration and movement of their first-stage larvae. Pulmonary tissue samples are frequently used for the post-mortem diagnosis of these parasites, but this kind of sample is not always available and easy to obtain. Faecal samples represent a more accessible choice for parasite monitoring. This work aimed to evaluate the agreement between the results obtained by the Baermann–Wetzel technique when samples of lung parenchyma or faeces from wild ruminants are used. A good level of agreement as well as a similar sensitivity between the two types of sample were observed, validating the use of faecal samples as a less invasive and cost-effective alternative for the monitoring of lungworm in wild ruminant populations.

Epidemiological approach to nematode polyparasitism occurring in a sympatric wild ruminant multi-host scenario

The epidemiology behind multi-host/multi-parasite systems is particularly interesting to investigate for a better understanding of the complex dynamics naturally occurring in wildlife populations. We aimed to approach the naturally occurring polyparasitism of gastrointestinal nematodes in a sympatric wild ruminant scenario present in south-east Spain. To this end, the gastrointestinal tract of 252 wild ruminants of four different species (red deer, Cervus elaphus; mouflon, Ovis aries musimon; Iberian ibex, Capra pyrenaica and fallow deer, Dama dama) were studied in Cazorla, Segura y Las Villas Natural Park (Andalusia, Spain). Of the analysed animals, 81.52% were positive for parasite infection and a total of 29 nematode species were identified. Out of these, 25 species were detected in at least two host species and 11 parasitized all ruminant species surveyed. The multi-host interaction between these nematodes and the four host species is discussed under the perspective of host family-based differences.

Bluetongue virus serotype 12 enters Australia – a further incursion of novel western lineage genome segments

Bluetongue virus (BTV) is an arbovirus (genus: Orbivirus) that occurs worldwide. It infects domestic and wild ruminant species and can cause disease in livestock, producing high economic impact. Recently, it gained extra prominence throughout Europe, with disease occurring in regions traditionally free of BTV. BTV enters Australia from Southeast Asia via wind-borne infected Culicoides spp. The first Australian isolation was 1975 (BTV-20) and further serotypes were isolated between 1979–86 (BTV-1, -3, -9, -15, -16, -21, -23). Despite increased, more sensitive, monitoring, no more were detected in over two decades, implying a stable BTV episystem of eastern ancestry. Isolations of BTV-2, -7 and -5 then occurred between 2007–15, with the latter two possessing genome segments with high sequence identity to western isolates. We report on the first isolation and genomic characterization of BTV-12, which revealed that three more novel western topotype gene segments have entered northern Australia.

Genomic Characterization and Phylogenetic Classification of Bovine Coronaviruses Through Whole Genome Sequence Analysis

Bovine coronavirus (BCoV) is zoonotically transmissible among species, since BCoV-like viruses have been detected in wild ruminants and humans. BCoV causing enteric and respiratory disease is widespread in cattle farms worldwide; however, limited information is available regarding the molecular characterization of BCoV because of its large genome size, despite its significant economic impact. This study aimed to better understand the genomic characterization and evolutionary dynamics of BCoV via comparative sequence and phylogenetic analyses through whole genome sequence analysis using 67 BCoV isolates collected throughout Japan from 2006 to 2017. On comparing the genomic sequences of the 67 BCoVs, genetic variations were detected in 5 of 10 open reading frames (ORFs) in the BCoV genome. Phylogenetic analysis using whole genomes from the 67 Japanese BCoV isolates in addition to those from 16 reference BCoV strains, revealed the existence of two major genotypes (classical and US wild ruminant genotypes). All Japanese BCoV isolates originated from the US wild ruminant genotype, and they tended to form the same clusters based on the year and farm of collection, not the disease type. Phylogenetic trees on hemagglutinin-esterase protein (HE), spike glycoprotein (S), nucleocapsid protein (N) genes and ORF1 revealed clusters similar to that on whole genome, suggesting that the evolution of BCoVs may be closely associated with variations in these genes. Furthermore, phylogenetic analysis of BCoV S genes including those of European and Asian BCoVs and human enteric coronavirus along with the Japanese BCoVs revealed that BCoVs differentiated into two major types (European and American types). Moreover, the European and American types were divided into eleven and three genotypes, respectively. Our analysis also demonstrated that BCoVs with different genotypes periodically emerged and predominantly circulated within the country. These findings provide useful information to elucidate the detailed molecular characterization of BCoVs, which have spread worldwide. Further genomic analyses of BCoV are essential to deepen the understanding of the evolution of this virus.