Spirometra erinaceieuropaei severely infect frogs and snakes from food markets in Guangdong, China: implications a highly risk for zoonotic sparganosis.

Sparganosis is a parasitic disease caused by plerocercoid larvae of the genus Spirometra. In China, the main source of sparganosis is from Guangdong, 16.1% of the country's human sparganosis cases occur in this province. Frequent international trade of amphibians and reptiles in Guangdong may introduce new species of Spirometra into the local market. In this study, a large-scale, high-intensity sampling survey was conducted to find out the causative species and epidemic situation of Sparganosis in Guangdong. The prevalence of sparganum infection in five species of frogs (Boulengerana guentheri, Fejervarya multistriata, Hoplobatrachus chinensis, Pelophylax nigromaculatus and Quasipaa spinosa) and nine species of snakes (Elaphe carinata, Lycodon rufozonatum, Hypsiscopus plumbea, Ptyas dhumnades, P. korros, P. mucosa, Naja atra, Sinonatrix annularis and Xenochrophis piscator) was investigated in Guangdong, Southern China from May 2014 to August 2015. The results showed that 9.8% (50/511) of the frogs and 40.8% (141/ 346) of snakes were found to be infected by plerocercoids (spargana). To identify the species of the collected spargana, a partial sequence of the mitochondrial cytochrome c oxidase subunit1 gene (cox1) was amplified and sequenced. Phylogenetic analysis identified all the spargana specimens as Spirometra erinaceieuropaei. Our study indicated that S. erinaceieuropaei, a highly pathogenic parasite, is the only causative agent of sparganosis in Guangdong, China. This study suggests that the large numbers of frogs and snakes in food markets in Guangdong may impact public health in China by transmitting S. erinaceieuropaei sparganum. Additional steps should be considered by the governments and public health agencies to prevent the risk of food-associated Spirometra infections in humans in China.