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.

Porcine hokovirus in wild boar in Portugal.

Porcine hokovirus (PHoV), also referred to as porcine parvovirus 4 (P-PARV4), a recently discovered parvovirus of swine that is closely related to human parvovirus 4/5 (H-PARV4/5), was first described in Hong Kong. To evaluate the occurrence of P-PARV4 in Portuguese wild boars in the hunting season of 2011/2012,liver and serum samples were tested. P-PARV4 was detected in 24 % of the wild boars analyzed. Phylogenetic analysis showed a close relationship between the P-PARV4 isolates and other P-PARV4 reference strains. This virus appears to be emerging, with yet unknown implications for public health.

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.