Toxoplasma gondii seroprevalence in raccoons (Procyon lotor) in France | Etude de Toxoplasma gondii chez le raton laveur (Procyon lotor) en France

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Inglés. Toxoplasma gondii is a zoonotic parasite that can infect warm-blooded animals and humans. The raccoon (Procyon lotor), an invasive species in Europe, can be an intermediate host for T.gondii, and is considered to be an indicator of environmental contamination in its native America. Numerous seroprevalence studies of T.gondii in raccoons have been carried out in North America, and in Central Europe where raccoons are nowadays widespread, with prevalence ranging from 13 to 84%. In the absence of published data in France, the aim of this study was to improve knowledge on seroprevalence as well as the presence of the parasite in raccoons from two of the three established populations in France, one in the Gironde department (sampling area G) and one in the north-east, with samples coming from the core (area NEC) and the north-eastern edge (area NEE) of this population.A total of 140 cardiac fluids and 70 thoracic fluids were collected and tested by the modified agglutination test (MAT), with 62 raccoons tested using both cardiac and thoracic fluids. T.gondii infection was detected by quantitative PCR on heart-extracted DNA from 141 raccoons. The results obtained by MAT showed no statistically significant difference between matrices, cardiac fluid or thoracic fluid, with 91.4% [IC95%: 85.5-95.5] and 85.7% [75.3-92.9] of seropositive samples, respectively. There was no statistical difference between population and sampling area, with 93.1%, 89.5% and 89.8% of cardiac fluid positive in NEE, NEC and G areas, respectively. Of the 62 samples tested with both cardiac and thoracic fluid, 51 (82.3%) were seropositive with both matrices, 3 (4.8%) were seropositive with thoracic fluid only and 6 (9.7%) were seropositive with cardiac fluid only. T. gondii DNA was detected in the heart of 19.1% of the raccoons tested by PCR (27/141), but the proportion of infected raccoons was higher in the North-east population (25%) than in Gironde population (8.2%) (p=0.02).The high seroprevalence that we observed indicates that T. gondii is widespread in the environment of raccoons in France and that they are highly exposed to the parasite certainly due to their alimentary habits. The detection of T.gondii DNA in hearts remains low when compared to the high seroprevalence of the animals. This could be explained by the fact that the distribution of T.gondii tissue cysts is not homogeneous and that parasite load is certainly low, which can influence the ability to detect the parasite's DNA. In any case, this study shows that raccoon is a good indicator of T. gondii contamination of its habitat in France.