Brucellosis of the European Brown Hare (Lepus europaeus)

Fatal toxoplasmosis in wild European brown hares (Lepus europaeus) in tularaemia endemic areas of the Czech Republic: Poses risk of infection for humans?

Toxoplasma gondii may cause fatal infection in European brown hares (Lepus europaeus). However, the role of this parasite in terms of mortality rate in tularaemia endemic areas, amount of parasites in affected organs and circulating genotypes, is still unknown. In total, 36 hares (killed or found dead) were submitted for pathomorphological examination as a part of the national tularaemia and brucellosis monitoring. Tissue samples (lung, heart, liver, spleen and kidney) were tested by quantitative real-time PCR targeting 529 bp region of T. gondii. Genotyping was performed by a 15 microsatellite markers method in a single multiplex PCR assay. The same tissues of hares were simultaneously used for the bacteriological cultivation. Toxoplasma gondii was detected by qPCR in the tissues of two hares. Spleen and lungs of one infected hare have been found harbouring up to ~7 millions of T. gondii parasites per gram of tissue. Both positive samples were characterized as T. gondii type II, one archetypal clonal type II and the other one a type II variant (W35 = 244). Bacteria Francisella tularensis was proved in pooled samples of three hares but without coinfection with T. gondii; all hares were negative for Brucella suis. Toxoplasma gondii has significant impact on mortality of European brown hares in tularaemia endemic areas and parasite load within the animal tissues may present high risk of human infection.

Surveillance of important bacterial and parasitic infections in Danish wild boars (Sus scrofa)

Background

Similar to the situation in other European countries, Danish wild boars may harbour a wide range of pathogens infectious to humans and domestic pigs. Although wild boars must be kept behind fences in Denmark, hunting and consumption of the meat may cause zoonotic transmission. Moreover, most infections of wild boars are transmissible to domestic pigs, which may have important economic consequences. The aim of this study was to investigate whether Danish wild boars were infected with bacteria and parasites transmissible to humans or domestic pigs: Brucella suis, methicillin-resistant Staphylococcus aureus (MRSA), Salmonella spp., Trichinella spp., lungworms and gastrointestinal parasites, especially Ascaris suum. This is the first study to investigate the prevalence of these important pathogens in Danish wild boars.

Results

Wild boars from eight enclosures were analysed over a 5-year period. All tested wild boars were negative for B. suis (n = 240), MRSA (n = 244), Salmonella spp. (n = 115) and Trichinella spp. (n = 232), while eight parasite genera were identified in the faeces (n = 254): Ascaris suum, Capillaria sp., Cystoisospora suis, Eimeria spp., Metastrongylus sp. (lungworm), Strongyloides ransomi, Trichuris suis and strongylid eggs, i.e. strongyles not identified to the genera. Eimeria spp. and Metastrongylus sp. had the highest prevalence (92.3 and 79.5%, respectively) and were identified in wild boars from all eight enclosures, while the remaining parasite genera were present more sporadically.

Conclusions

Wild boars from Denmark constitute a low risk of transmitting B. suis, MRSA, Salmonella spp. and Trichinella spp. to humans or domestic pigs, while economically important parasites transmissible to domestic pigs are highly prevalent in the wild boar population.

European Brown hare (Lepus europaeus) as a source of emerging and re-emerging pathogens of Public Health importance: A review

European brown hare (Lepus europaeus, EBH) is probably the most important game animal in Europe throughout its historical distribution. The decline in its populations across its geographic range in Europe have been attributed to factors such as reproductive rate and the ability for adaptation, climate, feed availability, predators, anthropogenic factors and diseases. Apart from common diseases of hares with a high impact on their mortality such as European Brown hare Syndrome, EBH has been involved in the epidemiology of pathogens with zoonotic potential. In this work, the role of EBH as a source of Crimean–Congo haemorrhagic fever virus (CCHFV), Hepatitis E virus (HEV), Yersinia spp., Brucella spp., Francisella tularensis, Toxoplasma gondii and Leishmania infantum is discussed. Hares may significantly contribute to the epidemiology of important emerging zoonotic pathogens through maintenance of high endemicity levels as in the case of CCHFV, as a reservoir of important pathogens such as Yersinia spp., B. suis, F. tularensis and L. infantum and as a potential source of T. gondii for other animals, especially for carnivores but also for humans. However, EBH may also be a host of minor importance as in the case of HEV. The continuous surveillance of hare populations will enable the collection of information on the population health status and the pathogens currently circulating in the area posing risk for wildlife, domestic animals and humans. The possible live animal translocations of infected hares, the fact that this species acts as a host of vectors (fleas, ticks, mosquitoes and sandflies) and the prey of carnivores and omnivores that travel in great distances getting into contact with domestic animals and humans, further highlights the need to be included in surveillance studies. Besides, the hunter‐harvested EBH population is an excellent indicator for recent pathogen transmission due to its short lifespan.

The present review provides an overview of the role of European Brown Hare as a source of Crimean–Congo haemorrhagic fever virus (CCHFV), Hepatitis E virus (HEV), Yersinia spp., Brucella spp., Francisella tularensis, Toxoplasma gondii and Leishmania infantum aiming to highlight the contribution of this species to the epidemiology of important emerging zoonotic pathogens.

Investigation of the Role of the European Brown Hare in the Epidemiology of Bacterial Zoonotic Pathogens: A Serological and Molecular Survey in Greece

The aim of this study was to investigate the occurrence of Bartonella spp, Brucella spp, Coxiella burnetii, and Francisella tularensis in European Brown hares (Lepus europaeus) hunter harvested during 2-year hunting periods in northern and central Greece. Serum samples were examined for the presence of IgG antibodies by using an immune fluorescence test and/or an enzyme-linked immunosorbent assay. PCR was used to detect Bartonella spp DNA in blood samples and Brucella spp, C. burnetii, and F. tularensis DNA in liver samples. Antibodies against Bartonella spp were detected in 12 hares (12/105); whereas none of the hares examined was seropositive for Brucella spp, C. burnetii, and F. tularensis. The presence of Bartonella spp, Brucella spp, C. burnetii, and F. tularensis DNA was not detected in the samples examined. This study did not provide any evidence that the European Brown hare is involved in the epidemiology of Brucella spp, C. burnetii, and F. tularensis in Greece. However, our results suggest that this species is exposed to Bartonella spp, which gives the impetus for further investigation of its role as another host of this bacterium.

Serologic Survey of Snowshoe Hares (Lepus americanus) in the Greater Yellowstone Area for Brucellosis, Tularemia, and Snowshoe Hare Virus

We examined sera from snowshoe hares (Lepus americanus) livetrapped in the northern Greater Yellowstone Area (GYA), US, for antibodies to Brucella abortus, Francisella tularensis, and snowshoe hare virus (SSHV). Zero of 90, 0 of 67, and 40 of 100 samples were antibody positive for B. abortus, F. tularensis, and SSHV, respectively. Hares were trapped from 2009 to 2012, and of the six animals that were captured twice with at least 1 yr between captures, four developed antibody to SSHV, indicating active exposure to the agent. These findings suggest snowshoe hares in the GYA do not play a significant role as a reservoir of B. abortus, but do maintain the zoonotic, encephalitic SSHV in the population.

Genetic relatedness of Brucella suis biovar 2 isolates from hares, wild boars and domestic pigs

Porcine brucellosis generally manifests as disorders in reproductive organs potentially leading to serious losses in the swine industry. Brucella suis biovar 2 is endemic in European wild boar (Sus scrofa) and hare (Lepus europeus, Lepus capensis) populations, thus these species may play a significant role in disease spread and serve as potential sources of infection for domestic pigs. The aim of this study was an epidemiologic analysis of porcine brucellosis in Hungary and a comparative analysis of B. suis bv. 2 strains from Europe using multiple-locus variable-number tandem repeat analysis (MLVA). MLVA-16 and its MLVA-11 subset were used to determine the genotypes of 68 B. suis bv. 2 isolates from Hungary and results were then compared to European MLVA genotypes. The analyses indicated relatively high genetic diversity of B. suis bv. 2 in Hungary. Strains isolated from hares and wild boars from Hungary showed substantial genetic divergence, suggesting separate lineages in each host and no instances of cross species infections. The closest relatives of strains from Hungarian wild boars and domestic pigs were mainly in the isolates from German and Croatian boars and pigs. The assessment of the European MLVA genotypes of wild boar isolates generally showed clustering based on geographic origin. The hare strains were relatively closely related to one another and did not cluster based on geographic origin. The limited relationships between geographic origin and genotype in isolates from hares might be the result of cross-border live animal translocation. The results could also suggest that certain B. suis strains are more adapted to hares. Across Europe, isolates from domestic pigs were closely related to isolates originating from both hares and wild boars, supporting the idea that wild animals are a source of brucellosis in domestic pigs.

A serological and bacteriological survey of brucellosis in wild boar (Sus scrofa) in Belgium

Background

Brucellosis is frequently reported among wild boar populations in Europe. The aim of the study was to assess the epidemiological situation in Belgium, regarding the steady increase of wild boar populations over the last decades. Several serological tests were used and compared with culture and IS711 polymerase chain reaction (PCR), to determine the most suitable combination of diagnostic tools for conducting a successful prevalence study in wildlife.

Results

An indirect enzyme-linked immunosorbent assay (iELISA) was used on 1168 sera from hunter-killed wild boar sampled between 2003 and 2007 in 4 natural regions of southern Belgium. Results gave an apparent prevalence of 54.88% (95% CI 52.03-57.73). Prevalence was significantly affected by age and by the year of study, but not by sex nor by the region of sampling. The relative sensitivities of the complement fixation test (CFT), the Rose Bengal test (RBT), and the slow agglutination test (SAT) versus the iELISA differed widely between tests, reaching 62.67%, 46.68%, and 34.77%, respectively. The relative specificities of the CFT, RBT and SAT versus the iELISA were respectively 99.01%, 92.49%, and 99.1%. From seropositive animals (iELISA), 9% were positive by culture and 24% by PCR when testing spleen and/or tonsils. Sensitivity of the PCR was higher on tonsils than on spleen. All bacterial isolates were identified as Brucella suis biovar 2.

Conclusions

Brucellosis is widespread among wild boar in southern Belgium, with seroprevalences having increased over ten years, and constitutes a growing risk of spillback to outdoor-farmed pig herds. The iELISA showed a better sensitivity than the CFT, RBT and SAT. Serological tests must be associated with direct diagnosis and PCR proved more sensitive than culture under wildlife sampling conditions. Spleen and tonsils are lymphoid tissues usually sampled in multi-disease monitoring programs. They remain top-grade organs for direct diagnosis of brucellosis, with a preference for tonsils.