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

Seroprevalence of infectious pathogens of zoonotic and veterinary importance in wild ruminants from Slovenia

Introduction

Wildlife represents an increasingly important source of pathogens of medical and veterinary importance. Surveillance in wildlife offers an insight on current epidemiological status of selected pathogens and help to prevent spillovers to humans and livestock.

Material and methods

Our study included 312 wild ruminants belonging to five species: Roe deer (n = 134), red deer (n = 113), Alpine chamois (n = 53), European mouflon (n = 10) and Alpine ibex (n = 2). Seven pathogens that may have profound effect on human/livestock health and economic viability of the farms were tested using serological methods.

Results

Antibodies against Toxoplasma gondii, Neospora caninum, Coxiella burnetii, Brucella spp., Chlamydophila abortus, Mycobacterium avium subsp. paratuberculosis (MAP) and Mycobacterium bovis were detected in 34.62% (108/312), 0.96% (3/312), 2.24% (7/312), 0, 0.96% (3/312), 0, 0.64% (2/312) of animals tested, respectively. Because of low prevalences, risk factors were assessed only for T. gondii. Sex (female>male) and species (roe deer>red deer, roe deer>Alpine chamois) were significantly associated with the T. gondii positive outcome, while age was not.

Discussion

Adult males had the lowest T. gondii prevalence which offers future research opportunities. The lower seroprevalence of most investigated pathogens suggests game meat, if properly cooked, as being relatively safe for human consumption. This is the first study investigating the seroprevalence and associated risk factors of selected pathogens in wild ruminants in Slovenia.

Comparison of Direct and Indirect Toxoplasma gondii Detection and Genotyping in Game: Relationship and Challenges

The importance of game as a source of Toxoplasma gondii (T. gondii) infection in humans is largely unknown. New data on the presence of T. gondii in game hunted in the Federal State of Brandenburg, Germany, were obtained by direct and indirect detection (ELISA). DNA extracted either directly (5 g heart or foreleg muscle, DE) or after acid pepsin digestion (50 g heart, PD) or enriched by magnetic capture (50 g heart, MC) was examined by real-time PCR (qPCR). ELISA revealed seroprevalences of 20% in wild boar (Sus scrofa), 11% in roe deer (Capreolus capreolus) and 6% in red deer (Cervus elaphus). T. gondii DNA was detected by at least one direct detection method in 12% of wild boar, 6% of roe deer, 2% of fallow deer (Dama dama) and 2% of red deer. In both, positive wild boar and roe deer, T. gondii type II specific alleles were the most prevalent, as assessed by PCR-restriction fragment length polymorphism. The highest proportion of positive animals was detected by MC qPCR, followed by PD qPCR with a similar proportion of positive findings. Investigation of 50 g of heart muscle revealed a significantly higher proportion of positive qPCR results than analysis of 5 g (p = 0.048). An association between seropositivity and direct detection was evident in wild boar and roe deer (p < 0.001). Infectivity of T. gondii DNA–positive samples was confirmed by bioassay (4/4), providing evidence that game could represent a relevant source of viable T. gondii posing a risk for human infection.

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.

Epidemiologic and Public Health Significance of Toxoplasma gondii Infections in Venison: 2009-2020

Toxoplasma gondii infections are common in humans and animals worldwide. The ingestion of food or water contaminated with oocysts excreted by infected cats or ingestion of uncooked or undercooked meat containing tissue cysts of T. gondii are the 2 major modes of transmission of T. gondii. Deer are a popular game. Recently, outbreaks of clinical toxoplasmosis were reported in humans in North America linked to ingestion of undercooked venison. Here, we review prevalence, persistence of infection, clinical disease, epidemiology, and public health risks of T. gondii infections in deer and other cervids for the past decade. Estimates of worldwide serological prevalence are summarized individually for each species of deer, elk, moose, and caribou. Genetic diversity of 112 viable isolates of T. gondii from cervids is discussed, including its public health significance. Prevalence of T. gondii in deer is very high. Any part of a deer, including liver, spleen, and muscles, should be cooked thoroughly before human consumption.

The global seroprevalence of Toxoplasma gondii in deer from 1978 to 2019: A systematic review and meta-analysis

Toxoplasma gondii infecting virtually all warm-blooded animals, including humans, is an intracellular protozoan parasite. The immunocompromised patients or pregnant women infected by Toxoplasma usually can cause encephalitis or abortion. Deer are also the important intermediate host of the parasite and people can be infected by ingesting the undercooked venison. Therefore, to raise the attention of the researchers and T. gondii infection on people in deer, we conducted the meta-analysis. All potential publications on the T. gondii infection in deer were retrieved by searching the PubMed, ScienceDirect, Springer- Link, China National Knowledge Infrastructure (CNKI), WanFang, and VIP Chinese Journal Databases. Finally, a total of 48 publications were included. The pooled seroprevalence of T. gondii infection in deer was 22.92% (95% CI 17.89-28.38) calculated by the random effect model. The seroprevalence of T. gondii infection in deer was the lowest in Asia (12.72%, 95% CI 6.29-20.89), and the highest in North America (32.21%, 95% CI 20.32-45.39). The highest point estimate of deer T. gondii in detection method subgroup was using MAT (31.28%, 95% CI 20.15-43.61). The estimated pooled seroprevalence of T. gondii infection in elk (63.50%, 95% CI 50.01-76.01) was higher than other types of deer. Our meta-regression analysis found that the subgroups including region, sampling year, age, climate, and deer species may be the main heterogeneous source in our meta-analysis. It is necessary to monitor the seroprevalence of T. gondii infection in deer at all times. Furthermore, people should be taken to precautions when ingesting the venison by cooking it well before serving to prevent the T. gondii infection via eating venison.