Open Access Research

Phylogenetic relationship of the Brazilian isolates of the rat lungworm Angiostrongylus cantonensis (Nematoda: Metastrongylidae) employing mitochondrial COI gene sequence data

Tainá CC Monte1, Raquel O Simões1, Ana Paula M Oliveira2, Clodoaldo F Novaes3, Silvana C Thiengo2, Alexandre J Silva4, Pedro C Estrela1 and Arnaldo Maldonado Júnior1*

Author Affiliations

1 Laboratório de Biologia e Parasitologia de Mamíferos Silvestres Reservatórios, Instituto Oswaldo Cruz, Avenida Brasil 4365, Manguinhos, 21040-360, Rio de Janeiro, Brazil

2 Laboratório de Referência Nacional em Malacologia Médica, Instituto Oswaldo Cruz, Avenida Brasil 4365, Manguinhos, 21040-360, Rio de Janeiro, Brazil

3 Secretaria de Saúde do Estado do Rio de Janeiro, Rua México 128, Centro, 20031-142, Rio de Janeiro, Brazil

4 Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Center for Global Health, 1600 Clifton Road, Atlanta, GA, 30333, USA

For all author emails, please log on.

Parasites & Vectors 2012, 5:248  doi:10.1186/1756-3305-5-248

Published: 6 November 2012

Abstract

Background

The rat lungworm Angiostrongylus cantonensis can cause eosinophilic meningoencephalitis in humans. This nematode’s main definitive hosts are rodents and its intermediate hosts are snails. This parasite was first described in China and currently is dispersed across several Pacific islands, Asia, Australia, Africa, some Caribbean islands and most recently in the Americas. Here, we report the genetic variability among A. cantonensis isolates from different geographical locations in Brazil using mitochondrial cytochrome c oxidase subunit I (COI) gene sequences.

Methods

The isolates of A. cantonensis were obtained from distinct geographical locations of Brazil. Genomic DNAs were extracted, amplified by polymerase reaction, purified and sequenced. A partial sequence of COI gene was determined to assess their phylogenetic relationship.

Results

The sequences of A. cantonensis were monophyletic. We identified a distinct clade that included all isolates of A. cantonensis from Brazil and Asia based on eight distinct haplotypes (ac1, ac2, ac3, ac4, ac5, ac6, ac7 and ac8) from a previous study. Interestingly, the Brazilian haplotype ac5 is clustered with isolates from Japan, and the Brazilian haplotype ac8 from Rio de Janeiro, São Paulo, Pará and Pernambuco states formed a distinct clade. There is a divergent Brazilian haplotype, which we named ac9, closely related to Chinese haplotype ac6 and Japanese haplotype ac7.

Conclusion

The genetic variation observed among Brazilian isolates supports the hypothesis that the appearance of A. cantonensis in Brazil is likely a result of multiple introductions of parasite-carrying rats, transported on ships due to active commerce with Africa and Asia during the European colonization period. The rapid spread of the intermediate host, Achatina fulica, also seems to have contributed to the dispersion of this parasite and the infection of the definitive host in different Brazilian regions.

Keywords:
Rattus norvegicus; Achatina fulica; Eosinophilic meningoencephalitis; Molecular phylogeny; Cytochrome c oxidase subunit I; Brazil