A pathological study of Leishmania infantum natural infection in European rabbits (Oryctolagus cuniculus) and Iberian hares (Lepus granatensis)

In this study, we describe the pathology of Leishmania infantum infection in naturally infected wild Leporidae and compare diagnosis of infection using histopathology, direct fluorescent antibody (DFA) assay, immunofluorescence antibody test (IFAT) and quantitative real‐time PCR (qPCR). Tissues were analysed from 52 European rabbits (Oryctolagus cuniculus) and 7 Iberian hares (Lepus granatensis) from the Community of Madrid (Spain). Our results show that L. infantum infection is associated with only minimal histopathological lesions and that L. infantum amastigotes can be detected by DFA assay in all tissues types tested, including skin. These results were confirmed by qPCR on fresh frozen tissues in 13% of rabbits and 100% of hares. However, L. infantum DNA could not be detected by qPCR on paraffin‐embedded tissue obtained by laser capture microdissection. Using the DFA assay to diagnose L. infantum, infection may provide further insights into this disease in wild animals and may allow the precise tissue localization of L. infantum, thereby guiding follow‐up tests with more accurate qPCR.     

First outbreak of myxomatosis in Iberian hares (Lepus granatensis)

Myxomatosis is an infectious disease caused by myxoma virus (MYXV; genus Leporipoxvirus), which affects the European wild rabbit (Oryctolagus cuniculus) and sporadically brown hares (Lepus europaeus). Here, we describe the first outbreak of myxomatosis in Iberian hares (Lepus granatensis). Between mid‐July and the end of September 2018, around 530 dead animals were detected in Iberian hare populations in southern Spain. The apparent mean mortality rate was 56.7%, and the estimated mean case fatality rate was 69.2%. Histopathological and molecular results confirmed MYXV infections in all hares analysed. To the authors’ knowledge, this is the first myxomatosis outbreak causing a high mortality in hares and the first detailed characterization of a myxomatosis outbreak in the Iberian hare. The absence of cases in sympatric wild rabbits suggests differences in the susceptibility between both lagomorph species to the virus strain implicated in the outbreak. After the first case, the number of affected areas increased sharply affecting most of the Iberian Peninsula where the Iberian hare is present. Further studies are required to elucidate the origin of the implicated MYXV strain as well as to assess the impact of this outbreak on the Iberian hare populations.     

Entomological risk factors for potential transmission of Rift Valley fever virus around concentrations of livestock in Colorado

Rift Valley fever virus (RVFV) poses a major threat of introduction to several continents, including North America. Such an introduction could cause significant losses to the livestock industry, in addition to substantial human morbidity and mortality. Because of the opportunistic blood host selection of Culex tarsalis mosquitoes, we hypothesized that this species could be an important bridge vector of RVFV near feedlots in the event of an introduction. We investigated the mosquito community composition at livestock feedlots and surrounding natural and residential areas to determine differences in mosquito relative abundance and blood feeding patterns attributed to cattle feeding operations. DNA extracted from abdomens of blood‐fed mosquitoes were sequenced to determine host identity. Multivariate regression analyses revealed differences between mosquito community assemblages at feedlots and non‐feedlot sites (p < 0.05), with this effect driven largely by differential abundances of Aedes vexans (p_adj < 0.05). Mosquito diversity was lower on feedlots than surrounding areas for three out of four feedlots. Culex tarsalis was abundant at both feedlots and nearby sites. Diverse vertebrate blood meals were detected in Cx. tarsalis at non‐feedlot sites, with a shift towards feeding on cattle at feedlots. These data support a potential for Cx. tarsalis to serve as a bridge vector of RVFV between livestock and humans in Colorado.     

Risk Profile of Hepatitis E Virus from Pigs or Pork in Canada

The role and importance of pigs and pork as sources of zoonotic hepatitis E virus (HEV) has been debated in Canada and abroad for over 20 years. To further investigate this question, we compiled data to populate a risk profile for HEV in pigs or pork in Canada. We organized the risk profile (RP) using the headings prescribed for a foodborne microbial risk assessment and used research synthesis methods and inputs wherever possible in populating the fields of this RP. A scoping review of potential public health risks of HEV, and two Canadian field surveys sampling finisher pigs, and retail pork chops and pork livers, provided inputs to inform this RP. We calculated summary estimates of prevalence using the Comprehensive Meta‐analysis 3 software, employing the method of moments. Overall, we found the incidence of sporadic locally acquired hepatitis E in Canada, compiled from peer‐reviewed literature or from diagnosis at the National Microbiology Laboratory to be low relative to other non‐endemic countries. In contrast, we found the prevalence of detection of HEV RNA in pigs and retail pork livers, to be comparable to that reported in the USA and Europe. We drafted risk categories (high/medium/low) for acquiring clinical hepatitis E from exposure to pigs or pork in Canada and hypothesize that the proportion of the Canadian population at high risk from either exposure is relatively small.     

Significant re‐emergence and recirculation of Schmallenberg virus in previously exposed dairy herds in Ireland in 2016

Schmallenberg virus (SBV) circulation was investigated in 25 previously exposed dairy herds in Ireland in 2016. A population of 1,550 spring‐2014‐born animals, which had been monitored for SBV infection in 2014 and 2015 as part of a previous SBV surveillance study, were resampled for evidence of SBV infection during 2016. A total of 366 blood samples were collected in the 25 study herds (15 samples per herd) between 3 March 2017 and 10 March 2017 (before the 2017 vector‐active season) and analysed for SBV antibodies using a competitive ELISA kit (IDVet). A total of 256 animals tested seropositive, an AP of 69.9% (95% CI: 65.1–74.4) and TP of 77.7% (95% CI: 72.3%–82.8%) when correcting for imperfect test characteristics. These results demonstrate that a new epidemic of SBV circulation occurred in these previously exposed herds in Ireland in 2016.     

Arrival of rabbit haemorrhagic disease virus 2 to northern Europe: Emergence and outbreaks in wild and domestic rabbits (Oryctolagus cuniculus) in Sweden

Incursion of rabbit haemorrhagic disease virus (RHDV ) into Sweden was documented in 1990 and it is now considered endemic in wild rabbit (Oryctolagus cuniculus ) populations. Rabbit haemorrhagic disease virus 2 (RHDV 2), a new, related lagovirus was first detected in France in 2010, and has spread rapidly throughout Europe and beyond. However, knowledge of RHDV 2 in northern Europe is sporadic and incomplete, and in Sweden, routinely available diagnostic methods to detect rabbit haemorrhagic disease (RHD ) do not distinguish between types of virus causing disease. Using RHDV 2‐specific RT ‐qPCR , sequencing of the VP 60 gene and immunological virus typing of archived and prospective case material from the National Veterinary Institute's (SVA ) wildlife disease surveillance programme and diagnostic pathology service, we describe the emergence of RHDV 2 in Sweden in both wild and domestic rabbits. The earliest documented outbreak occurred on 22 May 2013, and from May 2013 to May 2016, 10 separate incidents of RHDV 2 were documented from six different municipalities in the southern half of Sweden. Phylogenetic analysis of the VP 60 gene shows clear clustering of Swedish isolates into three separate clusters within two different clades according to geographic location and time, suggesting viral evolution, multiple introduction events or both. Almost all cases of RHD examined by SVA from May 2013 to May 2016 were caused by RHDV 2, suggesting that RHDV 2 may be replacing RHDV as the predominant cause of RHD in Sweden.     

Constant Hepatitis E Virus (HEV) Circulation in Wild Boar and Red Deer in Spain: An Increasing Concern Source of HEV Zoonotic Transmission

Hepatitis E is a viral zoonosis that affects multiple hosts. The complete dynamics of infection in wildlife are still unknown, but the previous fact facilitates the maintenance and circulation of the virus, posing a risk to human health in the case of meat consumption from susceptible animals. In Spain, it has been shown how domestic pigs, cattle and wildlife (i.e. wild boar and red deer) clearly interact in hunting farms, generating a complex epidemiological situation in terms of interspecies pathogen transmission. Therefore, in this study, we aimed to (i) evaluate the circulation of the virus in geographically close domestic (Iberian pigs) and wild animals (wild boar and deer) living in hunting areas from central Spain over an 8‐year period (2003–2010) and (ii) to determine whether HEV could be used as a marker of domestic–wildlife contact. For these purposes, a longitudinal analysis of Iberian pig, wild boar and red deer samples (n = 287) through virological and serological tests was conducted to shed light upon the circulation events of HEV. Regarding HEV RNA detection by real‐time RT‐PCR, 10.12% samples (95% CI: 5.44–14.8) from wild boar and 16.05% samples (95% CI: 8.06–24.04) from red deer were positive. As for the Iberian pigs, none of the 48 samples was positive for HEV RNA detection. In the serological analysis, 43.75% (95% CI: 29.75–57.75) from Iberian pig, 57.40% (95% CI: 48.10–66.70) from wild boar and 12.85% (95% CI: 5.01–20.69) samples from red deer presented anti‐HEV antibodies. Positive samples were distributed among all study years (2003–2010). These results depict the urgent need to improve the inspection and surveillance of these species and their products. In the case of HEV, it is clear that the stable and constant presence of the virus in wildlife and its contact with Iberian pigs pose a risk for human health as they are all destined for human consumption.     

Epidemiology of RHDV2 (Lagovirus europaeus/GI.2) in free‐living wild European rabbits in Portugal

As the detection of the first outbreak of a novel aetiological agent of rabbit haemorrhagic disease commonly called RHDV 2 or RHDV b (Lagovirus europaeus /GI .2, henceforth GI .2) in France in 2010, the virus rapidly spread throughout continental Europe and nearby islands such as Great Britain, Sardinia, Sicily, the Azores and the Canary Islands among others. The outbreaks of this new lagovirus cause important economic losses in rabbitries, and ecological disruptions by affecting the conservation of rabbit‐sensitive top predators. We analysed 550 rabbit carcasses collected in the field between May 2013 and March 2016, to investigate the epidemiology of GI .2 in free‐living populations and to perform a comparative analysis with the epidemiology of classical rabbit haemorrhagic disease virus forms (RHDV , henceforth GI .1) in Portugal. Rabbits were sexed, aged and liver and blood samples were collected for subsequent RHDV screening and serology. A total of 172 samples were PCR‐positive to GI .2, whereas GI .1 strains were not detected in any of the samples. The outbreaks of GI .2 revealed a marked seasonality, with peaks during the breeding season (November‐May). We also found that approximately, one‐third of free‐ranging European rabbits in Portugal have seroconverted to GI .2. We demonstrate that the GI .2 lagovirus is currently widespread in wild populations in Portugal and is affecting a high proportion of adults and juveniles. Therefore, ongoing monitoring and surveillance are required to assess the effects of GI .2 on wild rabbit populations, its evolution, and to guide management actions aimed at mitigating the impacts of rabbit declines in the ecosystem and in rural economies.     

Lack of Evidence of Spill‐Over of Salmonella enterica Between Cattle and Sympatric Iberian ibex (Capra pyrenaica) from a Protected Area in Catalonia,NE Spain

Salmonella enterica is a zoonotic agent of worldwide importance found in a wide range of wild hosts. However, its prevalence in many popular game species has never been assessed. Iberian ibex (Capra pyrenaica) is the main game caprinae of the Iberian Peninsula and around two thousand individuals are hunted every year for trophy or for home consumption. In this work, 313 Iberian ibexes from the Ports de Tortosa i Beseit National Game Reserve (NE Spain) were tested for Salmonella enterica in faeces, and anti microbial susceptibility was determined. The exact location of shooting or capture was recorded with a GPS device to study the links of Salmonella infection with cattle presence and human proximity. Additionally, samples were taken from cattle grazing inside this reserve (n = 73). Only three Iberian ibexes (0.96%, 95% CI 0.2–2.8) were positive to Salmonella (serotype Enteritidis, Bardo and 35:r:z35), while prevalence was moderate in cattle: 21.92% (95% CI 13.10–33.14, serotype Meleagridis, Anatum, Kedougou and Othmarschen). All isolates were susceptible to the anti microbial agents tested. Moreover, a case of fatal septicaemic salmonellosis in an 11‐year‐old male Iberian ibex is described where Salmonella enterica serotype Enteritidis was isolated from the lung, liver and spleen samples. The low prevalence of Salmonella in Iberian ibex and the lack of shared serotypes suggest no association to cattle. Despite this, game meat aimed for human consumption should be examined, and it is strongly recommended that hunters and game keepers manipulate animals and carcasses under maximal hygienic conditions to avoid environmental contamination and human contagion.