Prevalence and distribution of infectious and parasitic agents in roe deer from Spain and their possible role as reservoirs

Helminth fauna in roe deer (Capreolus capreolus Linnaeus, 1758) in the province of Grosseto (central Italy)

Helminth infection was analysed at necropsy and coprology in a total of 54 roe deer from the province of Grosseto (central Italy) between 2018 - 2020. Age and sex data were recorded for each deer for a total of 31 adults (23 females, 8 males) and 23 juveniles (11 females, 12 males). The results on the small intestine (51 samples) highlighted that nematodes belonging to the species Trichostrongylus colubriformis were the most prevalent parasite (41.2 %), followed by the cestode Moniezia expansa (7.8 %). The large intestine results (52 samples) showed Trichuris spp. (53.8 %), Oesophagostomum venulosum (50 %) and Chabertia ovina (26.9 %). In the abomasum, only Ostertagia ostertagi (17.9 %) was found. Of the 34 samples analysed by bronchopulmonary, only the lung of an adult female was positive for Dictyocaulus spp. In two livers out of 33 samples analysed, nematodes of the species Setaria tundra were found on the surface. Copropositivity was observed in 45 of the 52 faecal samples analysed. The results of the present study indicate that the roe deer is host to several species of parasites, which are also common in other cervids and domestic ruminants. Statistical testing highlighted a significant difference between mean intensities in males and females.

Occurrence of Cephenemyia Stimulator Larvae in Male Roe Deer (Capreolus Capreolus L.) in The Lublin Upland, Poland, and Their Impact on Particular Animal Health Indicators

Introduction

The aim of the study was to carry out epizootic assessment of male roe deer to detect the presence of Cephenemyia stimulator larvae and determine the influence of the parasite on the carcass and antler weight in animals living in different habitats.

Material and Methods

The investigations were based on post-mortem analysis of Cephenemyia stimulator infestations of the nasal passages and throat of 177 male roe deer culled between May 11 and September 30, 2020 in hunting districts of the Lublin region in Poland. The individual quality of the animals was assessed by weighing the gutted carcasses after cooling, and the antlers were weighed after dissection and their total weight was determined.

Results

The parasite prevalence ranged from18 to 48% according to habitat type, with a mean value of 33%. The highest prevalence was detected in bucks living in grassland ecosystems. The presence of the parasites exerted influence on the individual condition of the animals, which was reflected in reduced carcass and antler weight. The differences were found both in young individuals and in somatically fully developed animals, but they were not statistically significant in all age groups.

Conclusion

Although the parasitic infestations impaired the individual condition traits, their parametric values in most cases were not lower than those reported from other regions of Poland. Despite the Cephenemyia stimulator infestation, male roe deer from the Lublin region are characterised by high carcass and antler weight.

An Update on Cephenemyiosis in the European Roe Deer: Emergent Myiasis in Spain

Cephenemyia stimulator is a Palearctic species developing in the nasal cavity and pharynx of roe deer (Capreolus capreolus). It is widely spread in the range of distribution of this ungulate in Europe. Since the first report of C. stimulator in Spain in 2001, a rapid geographic expansion has been observed, first in the north of the country, with high prevalence and intensities of infestation that caused some mortal cases, and, lately, also in Extremadura and Andalucía, the southernmost populations of European roe deer. These observations suggest an adaptation of this parasite to different ecosystems of the Iberian Peninsula. Almost simultaneously, C. stimulator is also expanding its range to northern Europe, with the first cases being reported in Sweden. Thus, Cephenemyia stimulator may be an example of a parasite currently displaying distributional changes along its southernmost and northernmost range margins. Thus, it is of the utmost importance to unravel all the epidemiological and clinical aspects of this myiasis, as well as implementing surveillance measures including reliable and non-invasive diagnostic techniques to monitor its expansion and adaptation to different ecosystems and/or hosts and to reduce the negative impact on roe deer populations.

Diversity of Anaplasma species and importance of mixed infections in roe deer from Spain

Although wildlife can act as reservoirs of some Anaplasma species, studies on the presence and distribution of Anaplasma spp. in wild cervids are mainly limited and focused on zoonotic species. In order to identify the Anaplasma species in roe deer from Spain and to detect co-infections, 224 spleen samples were tested for Anaplasma spp. using a commercial qPCR; positive samples were further characterized using generic 16S rRNA primers and species-specific primers targeting the msp2 and groEL genes. Anaplasma DNA was detected in the 50.9% of samples, and four Anaplasma species were identified. Anaplasma phagocytophilum (43.8%) was predominant, followed by Anaplasma bovis (13.8%), Anaplasma capra (5.8%) and Anaplasma ovis (2.2%). In addition, strains similar to Anaplasma platys were found in nine animals. Most positive roe deer (71.9%) were infected with a single Anaplasma species, whereas co-infections with two (19.3%) or three (8.8%) Anaplasma species were also found. This study confirms the widespread occurrence of Anaplasma spp. in roe deer from Spain, being the first report of A. platys-like strains and A. capra in this cervid; it is also the first report of A. capra in Spain. The detection of Anaplasma species pathogenic for humans and/or domestic animals in roe deer suggests that this cervid may play a role in the sylvatic cycle of these bacteria contributing to the appearance of clinical anaplasmosis cases. In addition, co-infections are common in roe deer revealing that Anaplasma species specific PCR assays are essential for a reliable identification as well as for determining their real prevalence.

Seroepidemiology of Toxoplasma gondii in wild ruminants in Spain

Toxoplasmosis is a parasitic zoonosis caused by Toxoplasma gondii which infects warm-blooded species worldwide. Humans can be infected through ingestion of tissue cysts from raw or undercooked meat, including game meat. A nationwide large-scale cross-sectional study was conducted to assess exposure to T. gondii in seven wild ruminant species in Spain. A total of 2,040 serum samples from 77 sampling sites randomly distributed in the five bioregions (BRs) covering mainland Spain were tested for antibodies against T. gondii using the modified agglutination test. The overall seroprevalence was 22.0% (449/2,040). Seroprevalence by species in decreasing order was as follows: 39.6% (141/356) in roe deer (Capreolus capreolus), 37.1% (138/372) in fallow deer (Dama dama), 16.6% (92/553) in red deer (Cervus elaphus), 14.0% (26/186) in Southern chamois (Rupicapra pyrenaica), 11.5% (24/209) in mouflon (Ovis aries musimon), 7.8% (27/346) in Iberian wild goat (Capra pyrenaica) and 5.6% (1/18) in Barbary sheep (Ammotragus lervia). Seropositivity was detected in 74.0% (57/77) of the sampling sites. Results indicate widespread but not homogeneous exposure to T. gondii in wild ruminant populations in Spain during the last two decades and highlight differences related to animal species and spatial distribution of these species in this country; this implies potential consequences of T. gondii for animal health, conservation and public health.

Coprological Survey of Protostrongylid Infections in Antelopes from Souss-Massa National Park (Morocco)

Protostrongylids, small nematode lungworms, are an integral part of the wild ruminant helminth community, which can damage animals' health when they are held in captivity or semi-captive conditions. The Sahelo-Saharan antelope species dorcas gazelle (Gazella dorcas), the scimitar-horned oryx (Oryx dammah), and the addax (Addax nasomacculatus), reintroduced to Souss-Massa National Park in Morocco, could be host to many species of Protostrongylids. This study was conducted from January to July 2015 to identify infecting parasite species, and determine their prevalence and abundance in all three antelope species. A total of 180 individual fecal samples were collected, morphologically examined by the Baermann technique, and molecularly identified by PCR amplification and sequencing of the second internal transcribed spacer region of the rDNA (ITS-2). Two parasite species were found in the three antelope populations: Muellerius capillaris and Neostrongylus linearis. The prevalence scores recorded for M. capillaris were 98.40 % in the addax, 96.70 % in dorcas gazelle, and 28.40 % in the oryx. The prevalence rates of N. linearis were 60 % in the addax, 23.40 % in dorcas gazelle, and 90 % in the oryx. Excreted larvae were quantified by LPG (larvae per gram) counting: for M. capillaris, the LPG mean values were 92.94 in the addax, 133.09 in dorcas gazelle, and 1.48 in the oryx; and for N. linearis, the LPG mean values were 6.02 in the addax, 1.37 in dorcas gazelle, and 32.81 in the oryx. These findings indicate that the three species of antelopes are infected with Muellerius capillaris and Neostrongylus linearis to varying degrees in intensity and prevalence.

A systematic review and meta-analysis of Toxoplasma gondii in roe deer (Capreolus capreolus) and red deer (Cervus elaphus) in Europe

The objective of this systematic review and meta-analysis was to summarize the available knowledge on the seroprevalence of T. gondii in roe deer (Capreolus capreolus) and red deer (Cervus elaphus) in Europe. A computerized literature search of electronic databases (PubMed and CAB abstracts) was performed along with hand searches of library resources for relevant papers, books, abstracts and conference proceedings. A random-effect model was employed to calculate pooled seroprevalence estimates with 95% confidence intervals, and I² statistic was used to assess heterogeneity. Further, moderator analysis was performed to evaluate the effect of geographical area on the seroprevalence in roe deer. From a total of 190 studies initially identified, 16 and 8 articles were included for roe deer and red deer, respectively. These comprise 3,913 roe deer and 2,913 red deer from different European countries. The pooled seroprevalence was estimated to be 29% (95% CI: 23%-35%) in roe deer and 15% (95% CI: 10%-20%) in red deer. High heterogeneity was detected in the seroprevalence data within each species. In roe deer, the pooled seroprevalence estimate was significantly different according to geographical area with 40% (95% CI: 31%-49%) in Western Europe, 31% (95% CI: 21%-43%) in Northern Europe, 27% (95% CI: 15%-41%) in Eastern Europe and 21% (95% CI: 14%-28%) in Southern Europe. The present study indicates a moderate exposure to T. gondii in roe deer and red deer in Europe, with very high prevalence in Western Europe. Our results highlight the significant risk associated to the consumption of venison, encouraging proper handling and cooking of game meat to prevent toxoplasmosis in humans.

Distribution of Pestivirus exposure in wild ruminants in Spain

A large-scale study was carried out to determine the prevalence of antibodies against Pestivirus species in wild ruminants and describe their spatial variation in mainland Spain. Serum samples of 1,874 wild ruminants from different regions of this country were collected between the years 2000 and 2017. A total of 6.6% (123/1,874) animals showed antibodies against Pestivirus by both blocking ELISA (bELISA) and virus neutralization tests (VNT). The prevalence of antibodies against pestiviruses was different both among species and regions. Seroprevalence by species was 30.0% (75/250) in Southern chamois (Rupicapra pyrenaica), 7.0% (25/357) in fallow deer (Dama dama), 2.5% (10/401) in red deer (Cervus elaphus), 2.4% (8/330) in Iberian wild goat (Capra pyrenaica), 1.1% (4/369) in roe deer (Capreolus capreolus) and 0.8% (1/130) in mouflon (Ovis aries musimon), not detecting seropositivity (0/37) in Barbary sheep (Ammotragus lervia). The results confirm that exposure to pestiviruses was detected throughout mainland Spain, with significantly higher seroprevalence in Northern regions associated with the presence of Southern chamois. This indicates an endemic circulation of pestiviruses in Southern chamois and a limited circulation of these viruses in the remaining wild ruminant species during the last two decades, thus suggesting that non-chamois species are not true Pestivirus reservoirs in Spain. Nonetheless, the high spatial spread of these viruses points out that new epidemic outbreaks in naïve wild ruminant populations or transmission to livestock may occur, evidencing the usefulness of monitoring pestiviruses in wild ruminants, especially at the wildlife-livestock interface.

Control of tick infestations in wild roe deer (Capreolus capreolus) vaccinated with the Q38 Subolesin/Akirin chimera

Ticks (Acari: Ixodidae) are considered to be the most important vectors of disease-causing pathogens in domestic and wild animals, and emerging and re-emerging tick-borne diseases (TBD) exert an enormous impact on them. Wild ungulates are hosts for a wide variety of tick species and tick-borne pathogens that affect human and animal health. Consequently, the control of tick infestations and tick-borne pathogen prevalence is essential in some regions. Acaricides and animal management or culling have been used for the control of tick infestations and TBD, but tick vaccines constitute the best alternative to reduce the impact of acaricides on tick resistance and the environment. Previous results of controlled vaccination trials have shown that the Q38 Subolesin/Akirin chimera containing conserved protective epitopes could be a candidate universal antigen to control multiple tick species infestations. Thus, vaccination trials are necessary to validate these results under field conditions. In this study, we characterized the effect of Q38 vaccine on a wild population of European roe deer (Capreolus capreolus) in the Andalusian roe deer Reference Station (Junta de Andalucía, Cádiz, Spain). In this location, roe deer suffer especially severe parasitic conditions in some periods and commercial pesticides and ixodicides that are authorized to control ticks without specificity are frequently applied in the field, posing a threat to the environment. Animals vaccinated over a three-year period showed an antibody response to the vaccine antigen and a reduction in tick infestations by multiple species including Hyalomma marginatum, H. lusitanicum, Rhipicephalus bursa and Ixodes ricinus previously identified in roe deer, when compared to untreated controls. These results suggest the efficacy of Q38 for the control of tick infestations in wildlife.

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.

Serosurveillance of Schmallenberg virus in wild ruminants in Spain

Schmallenberg disease (SBD) is an emerging vector-borne disease that affects domestic and wild ruminants. A long-term serosurvey was conducted to assess exposure to Schmallenberg virus (SBV) in all the wild ruminant species present in mainland Spain. Between 2010 and 2016, sera from 1,216 animals were tested for antibodies against SBV using a commercial blocking ELISA. The overall prevalence of antibodies was 27.1% (95%CI: 24.7-29.7). Statistically significant differences among species were observed, with significantly higher seropositivity found in fallow deer (Dama dama) (45.6%; 99/217), red deer (Cervus elaphus) (31.6%; 97/307) and mouflon (Ovis aries musimon) (28.0%; 33/118) compared to Barbary sheep (Ammotragus lervia) (22.2%; 8/36), Iberian wild goat (Capra pyrenaica) (19.9%; 49/246), roe deer (Capreolus capreolus) (17.5%; 34/194) and Southern chamois (Rupicapra pyrenaica) (10.2%; 10/98). Seropositive animals were detected in 81.4% (57/70; 95%CI: 70.8-88.8) of the sampled populations. SBV seroprevalence ranged from 18.8% (48/256) in bioregion (BR)2 (north-central, Mediterranean) to 32.3% (31/96) in BR1 (northeastern or Atlantic, Eurosiberian). Anti-SBV antibodies were not found before 2012, when the first outbreak of SBD was reported in Spain. In contrast, seropositivity was detected uninterruptedly during the period 2012-2016 and anti-SBV antibodies were found in yearling animals in each of these years. Our results provide evidence of widespread endemic circulation of SBV among wild ruminant populations in mainland Spain in recent years. Surveillance in these species could be a useful tool for monitoring SBV in Europe, particularly in areas where wild ruminants share habitats with livestock.

Prevalence and molecular characterization of Anaplasma phagocytophilum in roe deer (Capreolus capreolus) from Spain

Anaplasma phagocytophilum can infect a wide range of vertebrates; nevertheless, some genetic variants are associated with particular species of tick vectors and animal hosts. It has been suggested that roe deer (Capreolus capreolus) mainly acts as a reservoir of several A. phagocytophilum non-pathogenic variants for other animal species. The aim of this study was to determine the prevalence and identify the genetic variants of A. phagocytophilum in roe deer from Spain in order to assess host-pathogen associations and their pathogenic potential. The spleens of 212 roe deer hunted in Spain were individually collected and analysed by a commercial qPCR kit in order to detect the presence of A. phagocytophilum DNA. Positive samples were further characterized at groESL, 16S rRNA and msp2 partial genes. The possible influence of several intrinsic (age and sex) and extrinsic factors (ecological area) on A. phagocytophilum prevalence was analysed using a logistic regression. Overall, 41.5 % of the samples resulted positive to A. phagocytophilum. The percentage of infected roe deer was significantly higher in the Mediterranean and Oceanic areas than in the Continental and Mountain regions; nevertheless, prevalence was not related to age or sex. Sequence analysis at groESL and 16S rRNA genes allowed the identification of three ecotypes (I to III) and four variants ("Y", "X", "W", "I"), respectively. A high percentage of roe deer from Spain is infected with different variants of A. phagocytophilum; these results have implications for public and animal health since some of these ecotypes and variants have been previously identified in both human and animal clinical cases.

The effect of livestock on the physiological condition of roe deer (Capreolus capreolus) is modulated by habitat quality

Free-range livestock grazing is a widespread human activity that not only modifies natural vegetation but also leads to interactions with wild ungulates. Most commonly, the interactions between cattle and wild ungulates have been studied with a focus on competition for high-quality forage. However, other mechanisms, such as the risk of parasite infection, might better describe this interaction. We aim to determine whether livestock affect roe deer (Capreolus capreolus Linnaeus, 1758) by reducing habitat quality and increasing the probability of infection by shared parasites. We measured noninvasive fecal cortisol metabolites as an indicator of habitat quality as well as the lung nematode larvae burden from the Dictyocaulus genus. A higher Dictyocaulus larvae load was found in the presence of livestock in pines, and feces collected in winter had a higher parasite load than feces collected in autumn. Additionally, fecal cortisol metabolite levels in the roe deer were affected by the interaction between habitat quality and livestock presence and were higher in the poorest habitat and when living in sympatry with cattle. Our results suggest that physiological stress responses in roe deer were mediated by the habitat type and the presence of competitors. The long-term implications of altered physiological responses such as those demonstrated here should be considered in management strategies for deer.

Prevalence and distribution of Babesia and Theileria species in roe deer from Spain

Babesiosis and Theileriosis are important worldwide-distributed tick-borne diseases for human and animals. Their presence in a particular area depends on the presence of suitable tick-vector and host species as well as competent reservoirs such as roe deer, one of the most abundant wild cervids in Spain. Spleen samples from 174 roe deer hunted in Spain were analysed to determine the prevalence of Babesia and Theileria species. DNA of both piroplasms was firstly detected using a commercial qPCR. Then, positive samples were molecularly characterized at the 18S rRNA and ITS1 genes of Babesia spp. and Theileria spp. The possible influence of some factors such as ecological area, age and sex was also assessed. Overall, 89.7% of roe deer were positive to any of the two piroplasms. Theileria spp. was more prevalent (60.9%) than Babesia spp. (19.0%); species identification could not be achieved in 17.3% of positive samples. Babesia prevalence was significantly higher in young animals and in roe deer from Oceanic regions, in contrast to Theileria spp. Five species were identified: Theileria sp. OT3 (60.3%), Babesia capreoli (15.5%), Babesia venatorum (2.9%), Theileria sp. 3185/02 (0.6%) and Babesia bigemina (0.6%). The coinfection B. capreoli/T. sp. OT3 was the most common (4.6%) followed by B. venatorum/T. sp. OT3 (0.6%) and B. bigemina/T. sp. OT3 (0.6%). Our results reveal that Theileria spp. and Babesia spp. are prevalent piroplasms in roe deer from Spain. These cervids can act as reservoirs for several Babesia and Theileria species, including the zoonotic B. venatorum. This study represents the first description of B. venatorum and B. bigemina in roe deer from Spain.

Description of the first Schmallenberg disease outbreak in Spain and subsequent virus spreading in domestic ruminants

Schmallenberg disease (SBD) is an emerging disease transmitted mainly among ruminant species by biting midges of the genus Culicoides. Since the Schmallenberg virus (SBV) was first identified in Germany in late 2011, it rapidly spread to other European countries. The aims of the present study were to describe the first SBD outbreak in Spain and to assess the spread and risk factors associated with SBV infection in domestic ruminants from nearby farms during the following year. In March 2012, one malformed stillborn lamb from a sheep farm located in Cordoba province (Southern Spain) was subjected to necropsy. Pathological compatible lesions and molecular analyses confirmed the first SBV infection in Spain. Afterwards, serum samples from 505 extensively reared domestic ruminants from 29 farms were analysed using both blocking ELISA and virus neutralization test against SBV. The overall seroprevalence was 54.4% (CI_95%: 50.0-58.7). Antibodies were detected in 70.6%, 46.0% and 34.8% of cattle, sheep and goats, respectively. A generalized estimating equation model indicated that the main risk factors associated with SBV infection were: species (cattle), age (adult), and absence of animal insecticide treatment. Pathological and molecular results confirmed the presence of SBV in Spain few months after it was firstly identified in Germany. The seroprevalence detected indicates a widespread circulation of SBV in nearby domestic ruminant farms one year after this first outbreak was reported in Spain. Further studies are warranted to determine the spatio-temporal trend of SBV in domestic ruminants in this country.

First report on the sero-epidemiology of Toxoplasma gondii infection in German roe deer (Capreolus capreolus)

While the roe deer (Capreolus capeolus) is the most important game species in Germany and its venison is popular, there is limited knowledge about the prevalence of Toxoplasma gondii in this animal population in the country, and in wild ungulates in Germany generally. Between 2013 and 2015, we collected 295 blood samples from roe deer belonging to a central German population. Sera were analysed using a modified agglutination test (MAT, cut-off 1:20), and antibodies were detected in 86 of the 295 samples (29%). Seroprevalence values differed significantly between the different age classes, with antibodies more frequently observed in adults. In contrast, seroprevalence did not differ significantly between the sexes or collection years. Venison is frequently consumed raw or undercooked and may be a potential source of human infection with T. gondii.