Monitoring the trends of Angiostrongylus cantonensis infection in humans and Pomacea spp. Snails in Dali, Yunnan, China, 2007–2021

We summarize historical events related to angiostrongyliasis and analyze surveys of clinically diagnosed and suspected cases of angiostrongyliasis in Dali from 2007 to 2021. We also randomly tested market sold Pomacea spp. snails to detect whether Angiostrongylus cantonensis was present in Dali market stalls from 2008 to 2021. There were a total of 125 cases of angiostrongyliasis (92 clinically diagnosed and 33 suspected) reported in the Dali Prefecture from 2007-2021. Of the 125 cases, 72 patients from 2010 to 2021 were investigated, with the main clinical manifestations being headache (100%), muscle pain (61%), neck stiffness (58.3%), paresthesia (58.3%), fever (55.5%), nausea (48.6%), coughing (26.3%), vomiting (44.4%), photophobia (18%), diplopia (25%), and visual impairment (5.5%). Laboratory testing showed cerebrospinal fluid qualitative protein levels and blood eosinophil levels were abnormal in 100% and 87.5% of patients tested, respectively. Moreover, of the 49,970 Pomacea spp. checked for A. cantonensis infection, 373 (0.75%) were found infected. Our study highlights the importance of enhancing public education, stricter food safety measures, and improved diagnostic methods to help mitigate future outbreaks of angiostrongyliasis.