A survey of free-ranging deer in Ireland for serological evidence of exposure to bovine viral diarrhoea virus, bovine herpes virus-1, bluetongue virus and Schmallenberg virus

Helminth Prevalence in European Deer with a Focus on Abomasal Nematodes and the Influence of Livestock Pasture Contact: A Meta-Analysis

Deer are susceptible to infection with parasitic helminths, including species which are of increasing economic concern to the livestock industry due to anthelmintic drug resistance. This paper systematically collates helminth prevalence data from deer across Europe and explores patterns in relation to host and parasite species, as well as landscape factors. A livestock pasture contact index (LPCI) is developed to predict epidemiological overlap between deer and livestock, and hence to examine deer helminth fauna in the context of their surrounding environment. Fifty-eight studies comprising fallow (Dama dama), red (Cervus elaphus), roe (Capreolus capreolus) and sika (Cervus nippon) deer were identified. Deer populations in "likely" contact with livestock pasture had a higher mean prevalence of the abomasal nematodes Haemonchus contortus, Ostertagia ostertagi, Teladorsagia circumcincta and Trichostrongylus axei (p = 0.01), which are common in livestock and not primarily associated with deer. Roe deer populations had a higher prevalence of T. circumcincta (p = 0.02) and T. axei (p = 0.01) than fallow deer and a higher prevalence of H. contortus than both red (p = 0.01) and fallow deer (p = 0.02). Liver fluke and lungworm species were present sporadically at low prevalence, while the abomasal nematode Ashworthius sidemi occurred locally at high prevalence. Insights from this research suggest that deer helminth fauna is reflective of their surrounding environment, including the livestock species which inhabit areas of shared grazing. This is explored from an epidemiological perspective, and the prospect of helminth transmission between wild and domestic hosts is discussed, including drug-resistant strains, alongside the role of helminths as indicators relevant to the transmission of other pathogens at the wildlife-livestock interface.

Prevalence of Mycobacterium bovis in deer in mainland China: a systematic review and meta-analysis

Background

Deer tuberculosis is a chronic zoonotic infectious disease, despite the existence of socio-economic and zoonotic risk factors, but at present, there has been no systematic review of deer tuberculosis prevalence in mainland China. The aim of this meta-analysis was to estimate the overall prevalence of deer TB in mainland China and to assess possible associations between potential risk factors and the prevalence of deer tuberculosis.

Methodology

This study was searched in six databases in Chinese and English, respectively (1981 to December 2023). Four authors independently reviewed the titles and abstracts of all retrieved articles to establish the inclusion exclusion criteria. Using the meta-analysis package estimated the combined effects. Cochran's Q-statistic was used to analyze heterogeneity. Funnel plots (symmetry) and used the Egger's test identifying publication bias. Trim-and-fill analysis methods were used for validation and sensitivity analysis. we also performed subgroup and meta-regression analyses.

Results

In this study, we obtained 4,400 studies, 20 cross-sectional studies were screened and conducted a systematic review and meta-analysis. Results show: The overall prevalence of tuberculosis in deer in mainland China was 16.1% (95% confidence interval (CI):10.5 24.6; (Deer tuberculosis infected 5,367 out of 22,215 deer in mainland China) 5,367/22215; 1981 to 2023). The prevalence in Central China was the highest 17.5% (95% CI:14.0-21.9; 63/362), and among provinces, the prevalence in Heilongjiang was the highest at 26.5% (95% CI:13.2-53.0; 1557/4291). Elaphurus davidianus was the most commonly infected species, with a prevalence of 35.3% (95% CI:18.5-67.2; 6/17). We also assessed the association between geographic risk factors and the incidence of deer tuberculosis.

Conclusion

Deer tuberculosis is still present in some areas of China. Assessing the association between risk factors and the prevalence of deer tuberculosis showed that reasonable and scientific-based breeding methods, a suitable breeding environment, and rapid and accurate detection methods could effectively reduce the prevalence of deer tuberculosis. In addition, in the management and operation of the breeding base, improving the scientific feed nutrition standards and establishing comprehensive standards for disease prevention, immunization, quarantine, treatment, and disinfection according to the breeding varieties and scale, are suggested as ways to reduce the prevalence of deer tuberculosis.

The first study on the occurrence of bovine herpesviruses in the wild fauna of the Moscow region, Russia

Background and Aim:

Some pathogens that cause infections in cattle are found in wild artiodactyls. Their prevalence, possible impact on the population of free-living animals, and the spread of infectious pathology in livestock have yet to be studied. We investigated the occurrence of bovine herpesviruses (BoHV-1, BoHV-4, and BoHV-6) among wild moose and roe deer in 8 areas of the Moscow region in the Russian Federation.

Materials and Methods:

One hundred and one tissue samples and nasal swabs of 24 moose and seven roe deer were studied using a real-time polymerase chain reaction (PCR) for BoHV-1 DNA and conventional PCR for BoHV-4 and BoHV-6 DNA. A virus neutralization test (VNT) was used to detect antibodies to BoHV-1 in 19 serum samples. The final antibody titer was calculated with the Spearman-Kärber method.

Results:

BoHV-4 and BoHV-6 DNA were not detected in all studied samples of 31 animals. BoHV-1 DNA was detected using a real-time PCR in nasal swabs from 2 adult roe deer. For BoHV-1, only 9/19 tested serum samples reacted positive in VNT with the titer range from 0.67 ± 0.19 to 3.75 ± 0.10 log2. Antibodies were detected in all age groups, more often in fawns under 1-year-old. The seropositivity of females was higher than in males.

Conclusion:

Wild ungulates can potentially represent a reservoir of new pathogenic livestock viruses. To study the prevalence and genetic diversity of wild ungulate herpesviruses, detailed molecular studies of the cervid herpesvirus 1, cervid herpesvirus 2, and elk herpesvirus 1 are necessary.

Pestivirus apparent prevalence in sheep and goats in Northern Ireland: A serological survey

BACKGROUND

Bovine viral diarrhoea virus (BVDV) and border disease virus (BDV) can cause significant health problems in ruminants and economic impacts for farmers. The aim of this study was to evaluate pestivirus exposure in Northern Ireland sheep and goat flocks, and to compare findings with a previous study from the region.

METHODS

Up to 20 animals were sampled from 188 sheep and 9 goat flocks (n = 3,418 animals; 3,372 sheep and 46 goats) for pestivirus antibodies. Differentiation of the causative agent in positive samples was inferred using serum neutralisation. Abortion samples from 177 ovine cases were tested by BVDV reverse-transcription polymerase chain reaction and antigen ELISA.

RESULTS

Apparent animal and flock (one antibody positive animal within a flock) prevalence was 1.7% and 17.3%, respectively, a statistically significant drop in apparent prevalence since a survey in 1999. 52.6% of samples testing positive had higher antibody titres to BVDV than to BDV. Of the ovine abortion samples, only one positive foetal fluid sample was detected by ELISA.

CONCLUSION

The present study found that, since 1999, there has been a decrease in apparent animal and flock prevalence of 3.7 and 12.8 percentage points respectively, suggesting pestivirus prevalence has decreased across Northern Ireland between 1999 and 2018.

A survey of shared pathogens at the domestic-wild ruminants' interface in Doñana National Park (Spain)

A cross-sectional study was carried out to evaluate shared pathogens that can be transmitted by close or non-close contact at the domestic-wild ruminants' interface. During summer-autumn 2015, a total of 138 cattle and 203 wild ruminants (red deer, Cervus elaphus, and fallow deer, Dama dama) were sampled in Doñana National Park (DNP, south-western Spain), a Mediterranean ecosystem well known for the interaction network occurring in the ungulate host community. Pestiviruses, bovine respiratory syncytial virus (BRSV; Bovine orthopneumovirus), bovine herpesvirus 1 (BoHV-1; Bovine alphaherpesvirus 1) and Mycobacterium tuberculosis complex (MTC) were assessed using serological, microbiological and molecular techniques. The overall seroprevalence against viruses in cattle was 2.2% for pestiviruses, 11.6% for BRSV and 27.5% for BoHV-1. No virus-specific antibodies were found in wildlife. MTC incidence in cattle was 15.9%, and MTC seroprevalence in wild ruminants was 14.3%. The same Mycobacterium bovis spoligotypes (SB1232, SB1230 and SB1610) were identified in cattle, red deer and fallow deer. The serological results for the selected respiratory viruses suggest epidemiological cycles only in cattle. Surveillance efforts in multi-host epidemiological scenarios are needed to better drive and prioritize control strategies for shared pathogens.

Bluetongue virus in South America: current status based on phylogenetic analysis

Bluetongue (BT) is an insect-borne disease affecting domestic and wild ruminants. Bluetongue virus (BTV) is the causative agent of the BT disease. BT outbreaks have been widely recorded worldwide. However, in the South American subcontinent, accurate information about the disease and molecular epidemiology is still lacking because little effort has been made to cover the region. This study comprises an exhaustive phylogenetic analysis including all BTV sequences available in databases and reports new Argentinean sequences for Seg 8 and Seg 9. Maximum-likelihood phylogenetic analyses were conducted for Seg 2, Seg 3, Seg 6, Seg 7, Seg 8, Seg 9 and Seg 10. Throughout the study, wide circulation and genetic continuity along the American continent were detected. Also, reassortment events are reported, and the historical virus introduction path into and through South America is suggested.

Serosurveillance and Molecular Investigation of Wild Deer in Australia Reveals Seroprevalence of Pestivirus Infection

Since deer were introduced into Australia in the mid-1800s, their wild populations have increased in size and distribution, posing a potential risk to the livestock industry, through their role in pathogen transmission cycles. In comparison to livestock, there are limited data on viral infections in all wildlife, including deer. The aim of this study was to assess blood samples from wild Australian deer for serological evidence of exposure to relevant viral livestock diseases. Blood samples collected across eastern Australia were tested by ELISA to detect antigens and antibodies against Pestivirus and antibodies against bovine herpesvirus 1. A subset of samples was also assessed by RT-PCR for Pestivirus, Simbu serogroup, epizootic hemorrhagic disease virus and bovine ephemeral fever virus. Our findings demonstrated a very low seroprevalence (3%) for ruminant Pestivirus, and none of the other viruses tested were detected. These results suggest that wild deer may currently be an incidental spill-over host (rather than a reservoir host) for Pestivirus. However, deer could be a future source of viral infections for domestic animals in Australia. Further investigations are needed to monitor pathogen activity and quantify possible future infectious disease impacts of wild deer on the Australian livestock industry.

Seroprevalence and Potential Risk Factors of Bluetongue Virus Infection in Domestic Cattle and Goats in Guangxi Province, Southern China

Bluetongue is one of the most important vector-borne viral diseases that can lead to significant economic losses as a result of reduction of productivity and even death in some susceptible ruminants. However, epidemiological information on bluetongue virus (BTV) infection in cattle and goats is scarce in China. To determine the seropositive rate and risk factors of BTV infection in cattle and goats in Guangxi province, a subtropical region in Southern China, a total of 548 cattle serum samples and 6567 goat serum samples collected from 13 cities across Guangxi province during 2003-2015 were analyzed and found that the seroprevalence is 44.5% (244/548) in cattle and 28.0% (1837/6567) in goats and the main BTV serotypes are BTV-1, -2, -4, and -8. Climatic zone, age, and species are found to be the likely risk factors for BTV infection. To our knowledge, this is the first large-scale serological survey for BTV infection in domestic cattle and goats in Guangxi province, Southern China.

Serological survey of wild cervids in England and Wales for bovine viral diarrhoea virus

BACKGROUND

Bovine viral diarrhoea (BVD) is a production disease commonly found in British cattle herds. Species other than cattle have been shown to be infected with the virus, thereby providing a potential source of infection for livestock. This study surveyed serum samples taken from 596 culled wild deer from England and Wales, between 2009 and 2010, for the presence of BVD antibodies.

METHODS

596 samples were tested with the SVANOVIR BVDV p80-Ab ELISA and a subset of 64 were tested with the IDEXX BVDV p80-Ab ELISA. ELISA results were confirmed using serum neutralisation tests.

RESULTS

2/596 samples (0.35 per cent) tested positive for BVD antibodies using the Svanova test and one of these tested positive and the other inconclusive using the IDEXX test; both were confirmed positive with serum neutralisation tests. These were both red deer stags, one from Devon and the other from East Anglia.

CONCLUSIONS

The results indicate that it is unlikely that BVD virus is widely circulating within the wild deer population and particularly unlikely that persistently infected deer are present in the populations surveyed. These results suggest that wild deer are unlikely to be a significant reservoir of BVD infection in cattle.

A Multi-Pathogen Screening of Captive Reindeer (Rangifer tarandus) in Germany Based on Serological and Molecular Assays

Captive reindeer in German zoos and wildlife parks live outside their natural geographic range and are exposed to a variety of viral, bacterial and protozoan pathogens, some host-specific and some which they are not exposed to in their native habitat. Reindeer blood samples and ticks collected in 2013 from 123 reindeer at 16 different zoological facilities were available from a previous study. The aims of this study were to assess the serological status of these animals with regards to various microorganisms as well as to test ticks (Ixodes ricinus) and blood samples for the presence of Anaplasma spp. DNA in order to evaluate the exposure of captive reindeer in Germany to a variety of pathogens. A total of 119 or 118 serum samples were screened (ELISA) and antibodies were detected (seropositive/tested, prevalence, confidence interval) against alphaherpesvirus (24/119, 20.3%, CI: 13.9–28.3), bluetongue virus (BTV; 4/119, 3.4%, CI: 1.0–8.7), malignant catarrhal fever related gammaherpesvirus (MCFV-related gammaherpesvirus; 7/119, 5.9%, CI: 2.7–11.9), pestivirus (5/118, 4.2%, CI: 1.6–9.8), Schmallenberg virus (SBV; 70/118, 59.3%, CI: 50.3–67.8), smooth Brucella spp. (1/118; 0.9%, CI: 0–5.1), Neospora caninum (5/118, 4.2%, CI: 1.6–9.8), and Toxoplasma gondii (62/119, 52.1%, CI: 43.2–60.9). These results suggested the exposure of reindeer to all tested pathogens. Moreover, real-time PCR for Anaplasma phagocytophilum targeting the partial msp2 gene was performed on DNA extracted from whole blood samples from reindeer (n = 123) and from ticks (n = 49) collected from 22 reindeer in seven different facilities. In addition to the real-time PCR, a semi-nested PCR for the partial groEL gene, and a nested PCR targeting the partial 16S rRNA gene were performed. DNA of A. phagocytophilum was detected in 17 reindeer (13.8%) and 15 ticks (30.6%). Three of the five reindeer with ticks having A. phagocytophilum DNA also had such DNA in blood. These results indicate that captive reindeer can be exposed to several ruminant pathogens that they hitherto had no known exposure to through their natural geographical distribution and habitats as shown for Culicoides-borne BTV and SBV. Further, captive reindeer may serve as reservoir hosts for pathogens circulating in local domestic, captive, and wild ruminant species and populations and arthropod vectors.

Schmallenberg virus: a systematic international literature review (2011-2019) from an Irish perspective

In Autumn 2011, nonspecific clinical signs of pyrexia, diarrhoea, and drop in milk yield were observed in dairy cattle near the German town of Schmallenberg at the Dutch/German border. Targeted veterinary diagnostic investigations for classical endemic and emerging viruses could not identify a causal agent. Blood samples were collected from animals with clinical signs and subjected to metagenomic analysis; a novel orthobunyavirus was identified and named Schmallenberg virus (SBV). In late 2011/early 2012, an epidemic of abortions and congenital malformations in calves, lambs and goat kids, characterised by arthrogryposis and hydranencephaly were reported in continental Europe. Subsequently, SBV RNA was confirmed in both aborted and congenitally malformed foetuses and also in Culicoides species biting midges. It soon became evident that SBV was an arthropod-borne teratogenic virus affecting domestic ruminants. SBV rapidly achieved a pan-European distribution with most countries confirming SBV infection within a year or two of the initial emergence. The first Irish case of SBV was confirmed in the south of the country in late 2012 in a bovine foetus.

Since SBV was first identified in 2011, a considerable body of scientific research has been conducted internationally describing this novel emerging virus. The aim of this systematic review is to provide a comprehensive synopsis of the most up-to-date scientific literature regarding the origin of SBV and the spread of the Schmallenberg epidemic, in addition to describing the species affected, clinical signs, pathogenesis, transmission, risk factors, impact, diagnostics, surveillance methods and control measures. This review also highlights current knowledge gaps in the scientific literature regarding SBV, most notably the requirement for further research to determine if, and to what extent, SBV circulation occurred in Europe and internationally during 2017 and 2018. Moreover, recommendations are also made regarding future arbovirus surveillance in Europe, specifically the establishment of a European-wide sentinel herd surveillance program, which incorporates bovine serology and Culicoides entomology and virology studies, at national and international level to monitor for the emergence and re-emergence of arboviruses such as SBV, bluetongue virus and other novel Culicoides-borne arboviruses.

Genotyping of Pestivirus A (Bovine Viral Diarrhea Virus 1) detected in faeces and in other specimens of domestic and wild ruminants at the wildlife-livestock interface

Pestiviruses are widespread in the world among ungulates and infect both domestic and wild animals causing severe economic losses in livestock. Bovine Viral Diarrhea Virus type 1 (BVDV-1), now re-designated as Pestivirus A, causes diseases mainly in cattle, while few data are available about infection in wild ruminants and about the role of these animals in viral maintenance and spread. In order to investigate BVDV-1 infection in domestic and wild ruminants, especially at the wildlife/livestock interface, bulk tank milk from dairy cattle and sheep and spleen from red deer, roe deer and fallow deer were analysed. Furthermore, faecal samples from Apennine chamois and from wild deer were evaluated as a suitable sample for detecting and genotyping pestiviruses. BVDV-1 RNA was found in all animal species tested but not sheep. Genotyping based on partial 5'UTR and N^pro sequences detected BVDV-1a in samples from Apennine chamois, red deer, roe deer and pasture-raised cattle, while BVDV-1c was found in a faecal sample from Apennine chamois and in a spleen sample from roe deer. For the first time BVDV-1 RNA was found and genotyped from faecal samples of wild ruminants and of cattle. BVDV-1a detection in Apennine chamois, red deer, roe deer and pasture-raised cattle suggests that the eventuality of viral transmission at the wildlife/livestock interface should be carefully evaluated. BVDV subgenotype 1c was found for the first time in roe deer and Apennine chamois in Central Italy, therefore the epidemiological role of these animals and the viral ecology should be further investigated.

Bubaline alphaherpesvirus 1 induces a latent/reactivable infection in goats

Latent infection is a common mechanism used by several alphaherpesviruses to persist in their host but it is not clear whether this mechanism is also triggered in heterologous infections. Cross-species infections have been documented repeatedly for alphaherpesviruses of ruminants, a group of closely related viruses. Herewith we report latent infection with bubaline alphaherpesvirus 1 (BuHV-1) in experimentally infected goats and subsequent virus reactivation after treatment with dexamethasone (DMS) at 10 months after infection. After DMS treatment, the virus was isolated in one such animal in the nasal swabs from day 3 to 9 post treatment and in the ocular swabs at day 6. The goat was euthanized 48 days after DMS treatment and viral DNA was detected by PCR in the trigeminal ganglia and in two cervical ganglia. Additionally, BuHV-1 DNA was detected by PCR in the trigeminal ganglia of the other 3 goats.

Spatial and risk factor analysis of bovine viral diarrhoea (BVD) virus after the first-year compulsory phase of BVD eradication programme in Northern Ireland

Bovine viral diarrhoea virus (BVDV) causes bovine viral diarrhoea (BVD), which is a contagious pathogen that can have a significant economic impact on cattle industries. In Northern Ireland (NI), the compulsory phase of a BVD eradication programme was implemented in 2016. The aim of this retrospective population based study was to utilize herd-level data after the first year of the compulsory phase (March 2016-March 2017) to determine the spatial distribution and variation of BVDV, to identify clusters of infection, and to quantify some risk factors associated with BVD in NI. Global spatial clustering (autocorrelation) and local spatial hot-spot analyses were used to specify the clustering areas (hot- and cold-spot). A suite of multivariable logistic analyses was performed to estimate the associations of spatial and non-spatial factors (relating to herd characteristics) with the risk of being a BVDV positive herd. Final models were compared by evaluating the model fit and the ability to account for spatial autocorrelation in the study area. There were 17,186 herds included in the analysis. The herd-level prevalence of BVDV was 11.31%. Significant spatial clustering of BVDV positive herds was presented in the central region of NI. A mixed effects logistic model, with a spatial random effect term, was considered the best model. The final model showed that a positive BVDV status during the voluntary phase prior to the compulsory phase started (OR = 2.25; CI 95% = 1.85-2.73), larger herd size (OR = 6.19; CI 95% = 5.22-7.34 for herd size > 100 animals) and a larger number of positive nearest neighbours within 4 km radius (OR = 1.24; CI 95% = 1.05-1.47 for 8-9 neighbours and OR = 1.41; CI 95% = 1.20-1.65 for 10-12 neighbours) were significantly related to the risk of a herd being tested positive for BVDV. The clear spatial pattern from the local spatial clustering analyses could be used for targeted surveillance and control measures by focusing on the central region of NI.

Prevalence and Risk Factors of Brucellosis, Chlamydiosis, and Bluetongue Among Sika Deer in Jilin Province in China

Brucellosis and chlamydiosis are important zoonotic diseases and bluetongue virus (BTV) is an arthropod-borne viral disease of ruminants. They are widely distributed around the world, cause large economic losses, and significant harmful effects on humans. However, epidemiological information relating to transmission from commercial sika deer in China is limited. Therefore, from 2016 to 2017, 458 sika deer blood samples were collected from three cities in Jilin Province in China. The Brucella antigen and specific antibodies to Chlamydia and BTV were examined using RT-PCR, indirect hemagglutination assay, and ELISA, respectively. The prevalence of Brucella was found to be 12.9% (59/458) and the seroprevalence of Chlamydia and BTV was 14.4% (66/458) and 17.0% (78/458), respectively. Seasonality was considered a risk factor for the presence of Brucella or BTV in sika deer and the region was considered a risk factor for Chlamydia infection. These data provides reference values for both further research and disease control.

Comparison Between the Fecal Bacterial Microbiota of Healthy and Diarrheic Captive Musk Deer

Diarrhea constitutes one of the most common diseases affecting the survival of captive musk deer and is usually caused by an imbalance in intestinal microbiota. Currently, research regarding the structure and function of intestinal microbiota in diarrheic musk deer is lacking. Therefore, in the present study, high-throughput 16S-rRNA gene sequencing was used to analyze the intestinal microbiota in feces of healthy captive musk deer (HMD) (n = 8) and musk deer with mild (MMD) (n = 8), and severe (n = 5) (SMD) diarrhea to compare the difference in intestinal microbiota of musk deer under various physiological conditions. The results showed that the diversity of HMD fecal microbiota was significantly higher than that of the two diarrhea samples. β Diversity results indicated that there were extremely significant differences in bacterial communities between the HMD sample and the MMD and SMD samples. However, no significant difference was found between the two diarrhea samples. LefSe analysis showed that the degree of intestinal physiological dysfunction in musk deer was correlated with the types of major pathogens. The main pathogen in the MMD group is Escherichia-Shigella, whereas Fusobacterium is the main pathogen in the SMD group. PICRUSt functional profile prediction indicated that the intestinal microbiota disorder could also lead to changes in the abundance of genes in metabolic pathways of the immune system. Altogether, this study provides a theoretical basis for the exploration of treatments for diarrhea in captive musk deer, which is of considerable significance to the implementation of the musk deer release into the wild program.