Leidi Laurimaa will defend her doctoral thesis titled "Echinococcus multilocularis and other zoonotic parasites in Estonian canids" on 8 June at 10:15.
Supervisors: Lead Research Fellow Urmas Saarma, PhD (TÜ ÖMI) ad Research Fellow Epp Moks, PhD
Opponent: Research Fellow Thomas Romig, PhD (Hohenheim University, Germany)
Summary: Zoonotic parasites are still a threat to public health not only in developing countries, but also in industrialised countries including Europe. In general, humans can acquire such parasites from a direct contact with an infected animal or by consuming water and foodstuffs contaminated with the infective stages of a parasite. The most dangerous parasite that can be transmitted from animals to humans is Echinococcus multilocularis. In Europe, the red fox and to a lesser extent also the raccoon dog are the main definitive host species for this cestode. However, adult worms can additionally develop in domestic dogs and cats. In Europe, during the last decades the number of red foxes has increased rapidly and they have colonised urban areas, bringing along their zoonotic pathogens. The main aim of the thesis was to study the prevalence of E. multilocularis among Estonian canids in both rural and urban areas. In addition, we studied the general parasite fauna of red foxes and raccoon dogs. In order to study urban canids new highly sensitive non-invasive molecular method that can identify both host and Echinococcus species from faecal samples was developed. Although the general parasite fauna of rural foxes and raccoon dogs is very similar, infection with life-threatening E. multilocularis was significantly higher in red foxes (31.5 %) compared to raccoon dogs (1.6 %), in which the cestode was reported for the first time in Estonia. The almost 20-fold difference in prevalence between the two host species can be explained by the difference in food preferences, especially their ability to capture rodents that serve as the main intermediate host for E. multilocularis. Analyses of faecal samples collected from urban areas in Tartu showed that 7.1 % of fox samples tested positive for E. multilocularis and 2.2 % of dog samples tested positive for E. granulosus, another zoonotic species from the genus Echinococcus. In conclusion, due to the high number of red foxes and raccoon dogs, both canid species can be considered as important sources of zoonotic parasites in Estonia.