The Global Spread Pattern of Rat Lungworm Based on Mitochondrial Genetics.

Area of Science:

• Parasitology
• Genomics
• Epidemiology

Background:

• Eosinophilic meningitis caused by Angiostrongylus cantonensis is a growing global health issue.
• New endemic areas for A. cantonensis infections include South America and Spain.
• Increasing genetic data offers insights into the parasite's worldwide dissemination.

Purpose of the Study:

• To analyze the global spread patterns of Angiostrongylus cantonensis using genetic data.
• To characterize gene types and phylogenies of A. cantonensis.
• To investigate the origins and distribution of A. cantonensis clades.

Main Methods:

• Sequencing of eight additional mitochondrial (mt) genomes of A. cantonensis.
• Phylogenetic analysis using Bayesian inference and network analysis on 554 mt genomes/fragments (1472 specimens).
• Characterization of gene types by mapping mt gene fragments to complete mt genomes.

Main Results:

• Phylogenetic and network analyses identified six main clades (I-VI) and additional clades (I2, II2, III2, V2, VII, VIII) based on cox1 and cytb genes.
• Haplotype diversity of A. cantonensis was significantly higher in Southeast and East Asia compared to other regions.
• Most samples (78/81) outside Southeast/East Asia belonged to Clade II, with higher diversity in the New World than the Pacific.

Conclusions:

• The genetic data suggests Angiostrongylus cantonensis was introduced from Southeast Asia.
• Clade II is the predominant lineage in regions outside Southeast Asia, particularly diverse in the New World.
• Further global research is recommended to fully understand the spread dynamics of rat lungworm.