Modelling transmission of bovine tuberculosis in red deer and wild boar in Normandy, France

In early 2001, Mycobacterium bovis infection was confirmed in red deer (RD) (Cervus elaphus) shot in Normandy region, France. An epidemiological survey conducted during the following hunting season in two connected forests confirmed the occurrence of the disease in both free-ranging RD and wild boar (WB) (Sus scrofa). This was the first detected bovine tuberculosis outbreak in wildlife in France. We present a simple deterministic age-structured model of the within- and between-species M.?bovis transmission in RD and WB populations that distinguishes direct transmission (horizontal and pseudo-vertical) and indirect transmission through contaminated offal left behind by hunters. Results issued from the epidemiological surveys conducted in Normandy forests were used to estimate transmission parameters. Because data for RD and WB populations were not available, population sizes at demographic equilibrium were estimated and used to run the model. We qualitatively tested different control measure scenarios with our model, considering different mortality rates and offal harvesting, to determine which ones affect the success of infection control. The most realistic control scenario would combine the total depopulation of RD and good compliance with offal harvesting, because the model suggests that infected offal left by hunters represents the main transmission source of M.?bovis in the field.     

Natural infection of red deer with bovine tuberculosis

Six bovine tuberculosis-free red deer hinds were introduced in October 1993 to a 1.8 ha enclosure, within a larger field study site known to contain tuberculous possums, and kept there for 9 months. A Mycobacterium bovis-infected possum was found in the vicinity of the deer enclosure 3 weeks after the introduction. Subsequently, a further eleven infected possums were found in the area. The deer were monitored by repeated composite antibody detection ELISA and lymphocyte transformation assays for tuberculosis, interpreted in parallel, by skin testing and by routine culturing of samples collected from potential excretion sites. Lymphocyte transformation assay evidence of M. bovis infection in four hinds was first observed 4 months after introduction. One other hind became bovine tuberculin lymphocyte transformation assay positive in the 5th month. Positive or equivocal bovine reactivity remained evident at most test episodes. A comparative cervical skin test performed in July 1994, shortly before slaughter, was positive in these five hinds. Mycobacterium bovis was recovered off swabs from the oropharyngeal tonsils of two hinds during routine sampling. Detailed necropsy of the six deer revealed a single typical tuberculous lesion in only one, but culturing of various tissue specimens ascertained that the five blood test and comparative cervical skin test-positive animals were all infected. Mycobacterium bovis was cultured from the oropharyngeal tonsils of four and medial retropharyngeal lymph nodes of two of the deer with no typical gross lesions. Six additional tuberculosis-free hinds were introduced to the enclosure in April 1994 and kept there for 12 months. Four of these animals showed a positive lymphocyte transformation assay response to M. bovis after 9 weeks, but no significant reactivity thereafter. Concurrent observational studies suggest that five of the first six deer probably became infected through close inspection and investigation of the tuberculous possums, although the possibility of deer-to-deer transmission cannot be totally excluded. The likely deer-possum contact, and thus exposure to M. bovis, was related to the curiosity and social ranking of the hinds. The second group appear to have had transient exposure to M. bovis, possibly caused by direct contact with the infected hinds introduced earlier. This group never showed any curiosity toward, or interaction with, possums during the periods of observation.     

Risk factors associated with the prevalence of tuberculosis-like lesions in fenced wild boar and red deer in south central Spain

In recent decades the management of large game mammals has become increasingly intensive in south central Spain (SCS), resulting in complex epidemiological scenarios for disease maintenance, and has probably impeded schemes to eradicate tuberculosis (TB) in domestic livestock. We conducted an analysis of risk factors which investigated associations between the pattern of tuberculosis-like lesions (TBL) in wild boar (Sus scrofa) and red deer (Cervus elaphus) across 19 hunting estates from SCS and an extensive set of variables related to game management, land use and habitat structure. The aggregation of wild boar at artificial watering sites was significantly associated with an increasing risk of detecting TBL in both species, which probably relates to enhanced opportunities for transmission. Aggregation of wild boar at feeding sites was also associated with increased risks of TBL in red deer. Hardwood Quercus spp. forest availability was marginally associated with an increased risk of TB in both species, whereas scrubland cover was associated with a reduced individual risk of TBL in the wild boar. It is concluded that management practices that encourage the aggregation of hosts, and some characteristics of Mediterranean habitats could increase the frequency and probability of both direct and indirect transmission of TB. These findings are of concern for both veterinary and public health authorities, and reveal tuberculosis itself as a potential limiting factor for the development and sustainability of such intensive game management systems in Spanish Mediterranean habitats.     

Wild boar and red deer display high prevalences of tuberculosis-like lesions in Spain

We describe the distribution of tuberculosis-like lesions (TBL) in wild boar (Sus scrofa) and red deer (Cervus elaphus) in Spain. Animals with TBL were confirmed in 84.21% of mixed populations (n=57) of red deer and wild boar and in 75% of populations of wild boar alone (n=8) in central and southern Spain (core area). The prevalence of TBL declined towards the periphery of this region. In the core area, the prevalence ranged up to 100% in local populations of wild boar (mean estate prevalence 42.51%) and up to 50% in red deer (mean estate prevalence 13.70%). We carried out exploratory statistical analyses to describe the epidemiology of TBL in both species throughout the core area. Prevalence of TBL increased with age in both species. Wild boar and red deer mean TBL prevalence at the estate level were positively associated, and lesion scores were consistently higher in wild boars than in red deer. The wild boar prevalence of TBL in wild boar did not differ between populations that were or were not cohabiting with red deer. Amongst the wild boars with TBL, 61.19% presented generalized lesions, and the proportion of generalized cases was similar between sex and age classes. In red deer, 57.14% of TBL-positive individuals presented generalized lesions, and the percentage of generalized cases increased with age class, but did not differ between the sexes. These results highlight the potential importance of wild boar and red deer in the maintenance of tuberculosis in south central Spain.     

Seroprevalence of Toxoplasma gondii in wild boar and deer in Brandenburg,Germany

Consumption of game in Germany has increased during the past 10 years. Wild boar (Sus scrofa), roe deer (Capreolus capreolus) and red deer (Cervus elaphus) are the most frequently hunted and consumed game animals in Germany, yet information on the occurrence of zoonotic pathogens in these animal species is scarce. To better estimate the public health risk emanating from handling and consumption of game, this study investigated seroprevalences of Toxoplasma gondii in game hunted in the German federal state of Brandenburg during two hunting seasons from 2017 to 2019. Toxoplasma gondii‐specific antibodies were detected in 24.4% (44/180, 95% CI: 18.4%–31.4%) of wild boar, 12.8% (16/125, 95% CI: 7.5%–20%) of roe deer and 6.4% (3/47, 95% CI: 1.3%–17.5%) of red deer using a commercial ELISA kit. Seroprevalences were similar in the two hunting seasons. Correlation between sex and seropositivity could not be observed. A rise in seroprevalence was seen with increasing age in all studied game species. Observed seroprevalences suggest that T. gondii is endemic in the sylvatic environment in the German federal state of Brandenburg and imply that game could represent a relevant source for human T. gondii infection.     

Serosurveillance of wild deer and wild boar after the epidemic of foot-and-mouth disease in The Netherlands in 2001

Blood samples from 140 wild deer and 208 wild boar shot in the aftermath of the epidemic of foot-and-mouth disease in The Netherlands in 2001 were examined for antibodies to foot-and-mouth disease virus. They were all negative.     

Experimental tuberculosis in red deer (Cervus elaphus)

This study was designed to investigate experimental Mycobacterium bovis infection of red deer (Cervus elaphus). Three intravenously inoculated deer (dose 10 microg-1000 microg) developed miliary tuberculosis of the lungs and all died within 28 days of being infected. No clinical illnesses were observed in four subcutaneously (dose 1 microg-1000 microg) and three intratracheally (dose 10 microg-100 microg) inoculated deer. At the conclusion of the experiment six weeks post inoculation, these seven animals reacted to 2 mg/ml of bovine purified protein derivative. The principal lesions in the intravenously inoculated deer were in the lungs which had multiple foci of necrosis containing very large numbers of acid fast bacilli. A gradation of changes was seen in the subcutaneously inoculated deer. The animal receiving the 1 microg dose only had lesions at the injection site and the draining prescapular lymph node. Deer receiving higher doses also had histopathological changes in the lungs and liver. Microscopic changes in the intratracheally infected animals were restricted to the thoracic cavity. The ability of the deer to controlled infection was related to the route of inoculation.     

Experimental tuberculosis in red deer (Cervus elaphus)

This study was designed to investigate experimental Mycobacterium bovis infection of red deer (Cervus elaphus). Three intravenously inoculated deer (dose 10µg–1000µg) developed miliary tuberculosis of the lungs and all died within 28 days of being infected. No clinical illnesses were observed in four subcutaneously (dose 1 uµg–100uµg) and three intratracheally (dose lµg–100µg) inoculated deer. At the conclusion of the experiment six weeks post inoculation, these seven animals reacted to 2 mg/ml of bovine purified protein derivative. The principal lesions in the intravenously inoculated deer were in the lungs which had multiple foci of necrosis containing very large numbers of acid fast bacilli. A gradation of changes was seen in the subcutaneously inoculated deer. The animal receiving the 1µg dose only had lesions at the injection site and the draining prescapular lymph node. Deer receiving higher doses also had histopathological changes in the lungs and liver. Microscopic changes in the intratracheally infected animals were restricted to the thoracic cavity. The ability of the deer to control infection was related to the route of inoculation.     

Leptospiral antibodies in Iberian red deer (Cervus elaphus hispanicus), fallow deer (Dama dama) and European wild boar (Sus scrofa) in Asturias,Northern Spain

Serum samples collected from Iberian red deer (Cervus elaphus hispanicus; n = 472), fallow deer (Dama dama; n = 293) and European wild boar (Sus scrofa; n = 174) in Asturias, Northern Spain, from 1999 to 2005 were examined for antibodies against a reference panel of 14 Leptospira spp. serovars. Positive antibody titres at a microscopic agglutination test cut-off of 1:80 were detected against serovars Pomona (1.6%, 5.8%, 5.2%), Bratislava (1.1%, 0.7%, 4.7%), Grippotyphosa (0.7%, 2.4%, 1.7%), Muenchen (2.6%, 0%, 0%), Pyrogenes (0.4%, 2.4%, 1.2%), Panama (1.2%, 1.7%, 0%), Copenhageni (0%, 0.7%, 0.6%), Autumnalis (0.4%, 0%, 0.6%) and Icterohaemorrhagiae (0%, 0%, 0.6%) in Iberian red deer, fallow deer and European wild boar, respectively.     

Comparison studies of the chemical,physical, technological,and microbiological characteristics of the European roe deer,boar, red deer,and beaver hunted wild game meat

The aim of this research was to perform comparison studies of the chemical, physical, technological, and microbiological characteristics, including biogenic amines (BAs) and volatile compounds (VC), of the European roe deer (RDM), boar (BoM), red deer (ReDM), and beaver (BM) hunted wild game meat (HWGM). The outcome of this study showed a significant effect (p < .05) of animal species on protein content, pH, drip loss, shear force, cooking loss, color coordinates, total count of enterobacteria, and most of the VC. ReDM had the highest protein content (23.15%), cooking loss, L* and b* values. The lowest protein and cholesterol content and L* value and the highest pH, shear force, drip loss, and fat content were established in BM having the highest content of unsaturated fatty acids (UFA) (64.12% from total FA). The total UFA content in ReDM and BM was almost twofold higher, compared with saturated FA. Small amounts of main BAs (<7.8 mg/kg) were found in ReDM and BM, while a higher content of putrescine in RDM and BoM was established. The main VCs in HWGM were acetoin, pelargonic, and acetic acid. These findings provide a valuable data about the HWGM quality characteristics and might aid food manufacturers to improve and enhance the processing of the HWGM.     

Urolithiasis in a wild red deer (Cervus elaphus) population

Renal calculi were found in eight of 325 red deer kidney pairs examined, all eight were females and only one was infected in both kidneys. A further three deer badly infected with urolithiasis were found by chance, two were males. Examples of the calculi found are illustrated to show their range of sizes and shapes. One calculus analysed for chemical composition comprised predominantly calcium carbonate.     

Farm and slaughter survey of bovine tuberculosis in captive deer in Switzerland

In 1998, a survey was conducted by postal questionnaire to gather basic knowledge about the management, health and productivity of captive deer in Switzerland. In addition, lymph nodes were collected from slaughtered deer from 124 of the 262 holdings surveyed, and tested for Mycobacterium bovis and Mycobacterium tuberculosis. The total farmed deer population was 8389 animals kept on 485 holdings; 87 per cent were fallow deer, 8 per cent red deer, 4 per cent sika deer, and there were small numbers of other species. The median herd sizes were 12 for fallow deer and eight for red deer. Few owners had handling facilities or crushes. In none of the lymph nodes examined were lesions typical of bovine tuberculosis observed, and neither M bovis nor M tuberculosis was cultivated from any of the samples.