Serological evidence of Toxoplasma gondii in hunted wild boar from Portugal

Toxoplasmosis is an important parasitic zoonosis with a worldwide distribution, being the parasitic disease with the highest occurrence in Europe. Wild boar has an important role in the epidemiological cycle of Toxoplasma gondii as an intermediate host, that can potentially infect humans when the meat is consumed raw or undercooked. The purpose of this work was to determine the presence of antibodies to T. gondii in serum of hunted wild boar. During the hunting season 2011/2012, sera samples were collected from 97 wild boar and tested for IgG antibodies to T. gondii, using the modified agglutination test. Twenty out of the 97 wild boar (20.6%) were seropositive for T. gondii IgG antibodies. Multivariate logistic regression analysis showed that males and older animals were associated with T. gondii seropositivity. These results show that T. gondii has an important presence in wild boar population from Portugal, suggesting a potential zoonotic risk for humans when wild boar meat or meat products are consumed raw or undercooked.

Toxoplasma gondii Infection in Hunted Wild Boars (Sus scrofa): Heart Meat Juice as an Alternative Sample to Serum for the Detection of Antibodies

Toxoplasmosis is a global zoonosis caused by the protozoan parasite Toxoplasma gondii. Detection of antibodies to T. gondii in serum samples from hunted animals may represent a key step for public health protection. It is also important to assess the circulation of this parasite in wild boar population. However, in hunted animals, collection of blood is not feasible and meat juice may represent an alternative sample. The purpose of the present study was to evaluate heart meat juice of hunted wild boars as an alternative sample for post-mortem detection of antibodies to T. gondii by modified agglutination test (MAT). The agreement beyond chance between results from meat juice assessed with Cohen’s kappa coefficient revealed that the 1:20 meat juice dilution provided the highest agreement. McNemars’s test further revealed 1:10 as the most suitable meat juice dilution, as the proportion of positive paired samples (serum and meat juice from the same animal) did not differ at this dilution. All together, these results suggest a reasonable accuracy of heart meat juice to detect antibodies to T. gondii by MAT and support it as an alternative sample in post-mortem analysis in hunted wild boars.

Unraveling Sarcocystis miescheriana and Sarcocystis suihominis infections in wild boar

Sarcocystis species are worldwide spread cyst-forming protozoa that can infect wild boar but little is known about the prevalence of these parasites. In this study we assessed the prevalence of Sarcocystis spp. infections in wild boars from northeastern Portugal, for which novel PCR testing assays targeting Sarcocystis genus, S. miescheriana and S. suihominis were implemented, and risk factors potentially associated with these infections were evaluated. Samples from muscle tissue, namely diaphragm (n = 102), oesophagus (n = 96) and heart (n = 101), were collected from a total of 103 wild boar hunted between October 2011 and February 2012. Diaphragm muscle was used for the PCR detection of Sarcocystis nucleic acids since a higher proportion of samples showed the presence of cysts during histological examination. PCR assay targeting Sarcocystis genus yielded a 73.8% infection rate, which indicate a high level of exposure to these protozoan parasites among wild boars. These samples showed to be positive with the S. miescheriana-specific PCR assay and no sample was positive with the S. suihominis-specific assay, suggesting that a single species infecting wild boar is circulating in Portugal. These results were confirmed by the partial sequencing of the 18S rRNA gene amplified from selected samples from different geographic regions. Adults, young adults and female wild boars were found to be more likely infected. Hunters have an important role in the life cycle of S. miescheriana since potentially infected viscera and carcasses can be left behind promoting the protozoan dissemination to the scavenging final hosts. If hunting dogs bite and ingest infected meat they can perpetuate the life cycle of Sarcocystis spp. spreading oocysts or sporocysts in the environment.