Direct detection and quantification of Toxoplasma gondii in meat samples from feral raccoons (Procyon lotor) in Germany by magnetic-capture real-time PCR

Abstract

Because the number of wild raccoons in Germany is increasing constantly, it appears to be economic reasonable to use their meat as food. For this purpose, it is essential to generate data regarding the pathogen load of the meat to be consumed and handled. It is known that raccoons, particularly in Germany, show a high seroprevalence of Toxoplasma gondii. Because serological data only indicates contact of a host to a parasite additional direct detection is needed to prove presence of parasitic stages in particular tissues. Therefore, a total of 150 samples from raccoons with known serostatus were tested and quantified using magnetic-capture real-time PCR for Toxoplasma gondii. As it represents potentially consumption-relevant parts of raccoons, meat from forelimb and hindlimb was examined. Samples were stratified into three groups based on the animals’ serostatus (each 50 negative, low positive, and high positive). All samples from seronegative animals were found negative by MC-PCR as well. In a total of 56 meat samples from 100 seropositive animals, T. gondii DNA was detected. Statistically significant more samples were positive by MC-PCR in the high positive than in the low positive serostatus group (38/50 vs. 18/50, p < 0.0001). Furthermore, samples from the former group were also found to have statistically significant higher DNA equivalent values compared to samples from the low positive serostatus group (p < 0.0001). These results suggest that meat from seropositive raccoons may contain considerable numbers of T. gondii presenting a potential public health risk for humans whilst handling and consumption.

Zoonotic Parasites in Feral Animals Commonly Consumed in Australia — Is There a Risk?

“…A number of the domestic species escaped or were deliberately released into the wild and are now living as established feral populations, including pigs, goats, buffalo, camels and cattle. Although wild game meat is more commonly eaten in many rural, remote and/or poor areas around the world [2], there has been a recent increase in the consumption of wild game meat in urban and higher socioeconomic regions [2][3][4][5] such as Australia. Wild game meat is considered rich in nutrients, low in fat and is usually sustainably sourced [3,6,7] which, along with the environmental benefits of removing feral species from the environment, has helped increase levels of consumption in Australia [3,8].…”

“…Zoonotic parasites and their associated diseases are well known throughout many parts of the world, where they are a major burden on public health and wellbeing [13][14][15][16], although there are limited data on the specific pathogens found in most wild game meat [5,6]. Within Australia, the study of parasites of wild animals has an opportunistic and sporadic history, with the study of parasites of wildlife, in general, not perceived as being of great social benefit and generally limited to those only with potential impacts on livestock [17].…”

“…Australia (and its neighbouring countries in the Western Pacific) has a very low global burden of foodborne diseases [18] based on the available literature. The increased utilisation of feral game meat includes the potential risk of infection through the handling and butchering of the animal, as well as from the consumption of raw or poorly cooked meat and organs [2,5,19,20]. Wildlife Health Australia listed various disease risks from feral animals in Australia, with feral pigs harbouring the majority of risks, but only the cestode Spirometra was listed as a risk able to be transmitted by the consumption of meat [21], although the Victorian Government stated that the diseases and pathogens of feral animals could present a food safety risk unless mitigating procedures were adopted and implemented [22].…”