The global distribution of Paragonimus species.

Abstract

BACKGROUND: Paragonimiasis, a foodborne zoonotic disease caused by Paragonimus (lung fluke) species, is prevalent mainly in tropical and subtropical regions. It is estimated that 23 million people are infected worldwide. Many reviews have been published in recent years, but very few reviews focused on distribution have been published. Here, we performed a review to map the global distribution of Paragonimus species. METHODS: We systematically searched Google Scholar, Web of Science, PubMed, ScienceDirect, African Journals Online, the Chinese National Knowledge Infrastructure (CNKI), Wanfang Database, and Chongqing VIP Chinese Science and Technology Journal Database to identify studies and case reports documenting the occurrences of Paragonimus species (OPSs) and cases of paragonimiasis. Studies were included only if both the OPSs and the geographical locations of Paragonimus species occurrence had been verified in the relevant research. Subsequently, we mapped the OPSs based on data extracted from the eligible included studies. RESULTS: We mapped the global distribution of Paragonimus species and cases caused by them. Paragonimus species are distributed in Asia, Africa, and the Americas, among which no species are distributed across continents. Eight species can infect humans: P. westermani (East Asia, the Far East, Southeast Asia, India, Sri Lanka, probably Nepal, New Guinea), P. skrjabini (mainly distributed in China and Japan), P. heterotremus (the Indochina Peninsula and southwestern border regions of China), P. kellicotti (USA and Canada), P. mexicanus (Latin America), P. africanus, P. uterobilateralis, and P. gondwanensis (West and Central Africa). This study suggests that Paragonimus species are distributed from 12° S to 50° N globally, except four "outliers" in South Africa (approximately 30° S). CONCLUSIONS: Globally, Paragonimus species and paragonimiasis cases exhibit an imbalanced distribution across hemispheres, continents, and countries. In many "suitable habitats", where infection by Paragonimus may be expected, few or no OPSs have been reported. Epidemiological and other studies are encouraged in these regions. This study will support the further refinement of paragonimiasis surveillance and response measures by global disease control authorities, thereby advancing public health.