Wild and domestic animals as hosts of Toxoplasma gondii in Finland

• Main Author: Jokelainen, Pikka
• Other Authors: Lundén, Anna, University of Helsinki, Faculty of Veterinary Medicine, Veterinary Pathology and Parasitology, Department of Veterinary Biosciences, Helsingin yliopisto, eläinlääketieteellinen tiedekunta, Helsingfors universitet, veterinärmedicinska fakulteten, Sukura, Antti, Oksanen, Antti
• Format: Doctoral or Postdoctoral Thesis
• Language: English
• Published: Helsingin yliopisto 2013
• Subjects: eläinlääketieteellinen parasitologia; Alces alces; Lynx; Lynx lynx lynx
• Online Access: http://hdl.handle.net/10138/40261

Toxoplasma gondii is a widespread protozoan parasite of humans, domestic animals, and wildlife. In this work including nationwide epidemiological cross-sectional studies and descriptive case series studies, T. gondii was confirmed as endemic, common, and sometimes fatal in a selection of animal hosts in Finland. Antibodies against T. gondii were detected in all host species investigated, including hosts hunted or raised for human consumption. The samples were screened with a commercial direct agglutination test using a conservative cut-off for seropositivity. Specific anti-T. gondii IgG antibodies were detected in 9.6% of the 1215 moose (Alces alces), 26.7% of the 135 white-tailed deer (Odocoileus virginianus), and 17.6% of the 17 roe deer (Capreolus capreolus) examined. Seropositive animals were found in 76.3% of 97 sheep farms and 60.0% of 25 wild boar farms, while antibodies were detected in 24.6% of the 1940 individual sheep (Ovis aries) and 33.0% of the 197 farmed wild boars (Sus scrofa) examined. Both of the possible definitive hosts present in Finland had commonly encountered the parasite: 48.4% of the 490 domestic cats (Felis catus) and 86.1%, a significantly higher proportion, of the 337 Eurasian lynx (Lynx lynx) tested seropositive. Raw meat in the diet was a major risk factor (odds ratio 2.0) for the infection in domestic cats. Evidence of exposure to T. gondii followed a north-south gradient in several hosts. The prevalence data indicate an environment contaminated with oocysts. PCR-confirmed T. gondii oocysts were found in one (0.8%) of the fecal samples from domestic cats. None of the lynx shed oocysts. Cats also died of toxoplasmosis; the proportional mortality rate was 3.1% among the 193 domestic cats examined postmortem. The first local T. gondii isolates (FIN1 and FIN2) were obtained from two cats into cell culture. Toxoplasma gondii also caused deaths in species considered highly susceptible to clinical toxoplasmosis. The proportional mortality rates were 8.1% in 173 European brown hares ...