Enzootic Angiostrongyliasis, Guangdong, China, 2008–2009

To the Editor: The nematode Angiostrongylus cantonensis was discovered in pulmonary arteries and hearts of domestic rats in Guangzhou (Canton), China, by Chen in 1935 (1). This parasite has a complex life cycle (2) and causes cerebral angiostrongyliasis after ingestion of infective larvae found in freshwater and terrestrial snails and slugs, paratenic hosts (such as freshwater fi sh, shrimp, frogs, and crabs), and contaminated vegetables (3). During 2000–2006, a total of 7 outbreaks of angiostrongyliasis were reported in the People's Republic of China, including an outbreak in Zhaoqing, Guangdong Province (4–6). We conducted a survey of A. It is the largest city in the province. Qingyuan borders Zhaoqing on the west and Guangzhou on the south. Its climate is subtropical monsoon, and it has an average annual temperature of 20.7°C. The city has an area of 19,152.89 km 2 and a population of 3.87 million. Rats were examined for adult A. cantonensis nematodes in pulmonary arteries and right heart cavities. Among the 288 rats examined, 27 (9.4%) from 3 species were infected with A. cantonensis adults in their cardiopulmonary systems (Table). Infected rodents were found in all 3 counties. The 27 infected rats were 25 R. norvegicus, 1 R. losea, and 1 M. musculus. R. norvegicus rats were most frequently captured in the 3 counties, and this rodent had the highest prevalence of infection. Infected B. indica rats in Lianzhou and M. musculus rats in Qingxin were also found, but the total numbers of infected animals and the prevalences are lower than that for R. norvegicus rats. On the basis of these fi ndings, we conclude that R. norvegicus rats are the major defi nitive host for A. cantonensis nematodes in Qingyuan. Specimens from 510 snails (144 Pomacea canaliculata, 306 Achatina fulica, and 60 Bradybaena despecta) were digested with pepsin for isolation of A. cantonensis larvae (7). Metastrongylid larvae were found in 21 (4.1%) of 510 examined snails. Prevalence rates of A. cantonensis in P. canaliculata, A. fulica, and B. despecta were 8.3%, 2.0% and 5.0%, respectively. Differences between the 3 prevalence rates were signifi cant (χ 2 9.604, p<0.05). Prevalence rates in the 3 counties are shown in the Table. All 3 species of infected snails were found in Qingxin and Fogan Counties. P. canaliculata and B. despecta snails were found infected in Qingxin County. However, only A. fulica snails were found infected in Fogang. These fi ndings are …