Toxoplasma gondii in the Eurasian kestrel (Falco tinnunculus) in northern Italy.

BACKGROUND: Identifying factors that sustain parasite transmission is important for understanding their spread and emergence, including how changes in biodiversity may affect parasite prevalence and spread. Toxoplasma gondii is a protozoan parasite infecting humans and animals. Birds can acquire T. gondii infection through ingestion either of oocysts from the ground or of tissue cysts present in infected prey and are therefore suitable indicators of the presence of T. gondii in the natural environment. METHODS: The aim of the study included the evaluation of T. gondii seroprevalence in clinically healthy Eurasian kestrels (Falco tinnunculus) using a modified agglutination test. Birds were captured in a small area of Parma (northern Italy) for two consecutive years (2016-2017), sex and age determined and serological study carried out. Food sources for the birds were also evaluated, in particular rodent and grasshopper population estimates in the study area. The biomass of rodents and grasshoppers per hectare was estimated in order to directly compare food availability. Statistical analyses were performed in order to evaluate factors influencing the probability of kestrels being T. gondii-seropositive using R 3.4.4 fitting linear mixed-effect models with the 'glmer' function of the package lme4, 'lsmean' in package lsmean for pair-wise post-hoc comparisons using differences of least square means (DLSM) and the 'betareg' function of the package betareg for beta regression. RESULTS: Seroprevalence for T. gondii was 33.3% (49/147) in 2016, while in 2017 seroprevalence decreased to 14.3% (13/91). An increase in the probability of kestrels being T. gondii-seropositive was associated with a higher rodent biomass in the environment, suggesting a positive feedback of the biotic factors driving infection risk. CONCLUSIONS: These results underline the need for multidisciplinary studies aimed at better understanding pathogen-host relationships and for predictions in disease ecology.

Lack of viable parasites in cured 'Parma Ham' (PDO), following experimental Toxoplasma gondii infection of pigs.

Twelve Large White pigs were experimentally infected with 1000 Toxoplasma gondii oocysts/each. Serology was carried out at different time points post infection (p.i.) and animals were slaughtered at four months p.i. One of two thighs was examined for T. gondii infection status by PCR and bioassay in mice. The other thigh was processed for Parma ham production. Four thighs were examined after twelve months of curing, four after fourteen months and four were examined after sixteen months. Cured hams were analyzed by PCR, bioassay and in-vitro cultivation on Vero cells followed by real-time PCR. Pigs seroconverted from day 21 p.i. Bioassays were positive for all fresh thighs, but negative for cured hams. PCR was positive for parasite DNA from most thighs both at slaughter and post curing, but parasite growth was not observed following in vitro cultivation and real-time PCR. Results indicate that the curing process of Parma Ham (PDO), when carried out according to the Parma Ham consortium regulations, can inactivate T. gondii tissue cysts. Results would suggest that food-borne transmission of T. gondii to consumers from Parma ham can be excluded.