Short report

Absence of Wolbachia endobacteria in the non-filariid nematodes Angiostrongylus cantonensis and A. costaricensis

Jeremy M Foster¹ , Sanjay Kumar¹ , Louise Ford² , Kelly L Johnston² , Renata Ben³ , Carlos Graeff-Teixeira³ and Mark J Taylor²

¹  Parasitology Division, New England Biolabs, 240 County Road, Ipswich, MA 01938, USA

²  Molecular and Biochemical Parasitology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK

³  Laboratório de Parasitologia Molecular, Instituto de Pesquisas Biomédicas da PUCRS, Porto Alegre, Brazil

author email corresponding author email

Parasites & Vectors 2008, 1:31doi:10.1186/1756-3305-1-31

Published:	18 September 2008

Abstract

The majority of filarial nematodes harbour Wolbachia endobacteria, including the major pathogenic species in humans, Onchocerca volvulus, Brugia malayi and Wuchereria bancrofti. These obligate endosymbionts have never been demonstrated unequivocally in any non-filariid nematode. However, a recent report described the detection by PCR of Wolbachia in the metastrongylid nematode, Angiostrongylus cantonensis (rat lungworm), a leading cause of eosinophilic meningitis in humans. To address the intriguing possibility of Wolbachia infection in nematode species distinct from the Family Onchocercidae, we used both PCR and immunohistochemistry to screen samples of A. cantonensis and A. costaricensis for the presence of this endosymbiont. We were unable to detect Wolbachia in either species using these methodologies. In addition, bioinformatic and phylogenetic analyses of the Wolbachia gene sequences reported previously from A. cantonensis indicate that they most likely result from contamination with DNA from arthropods and filarial nematodes. This study demonstrates the need for caution in relying solely on PCR for identification of new endosymbiont strains from invertebrate DNA samples.