Detection of Canine Vector-Borne Filariasis and Their Wolbachia Endosymbionts in French Guiana

Abstract

In French Guiana, canine heartworm disease is well known, but the diversity of filarial parasites of dogs remains largely unknown. A total of 98 canine blood samples from Cayenne and Kourou were assessed by a blood wet mount preparation, heartworm antigen test and molecular exploration of filarioid and <i>Wolbachia</i> DNAs, followed by a multiplex species-specific qPCR's identification and a subsequent sequencing analysis. Thereafter, a phylogeny based on maximum likelihood was carried out to facilitate specific identification. Five dogs were microfilaremic. Heartworm antigens were detected in 15 (15.3%) dogs. Of these, six (6.1%) were considered as occult infections as neither microfilariae nor <i>Dirofilaria immitis</i> DNA were detected. The 11 (11.2%) <i>D. immitis</i> isolates corresponded to a low virulent strain. Six of the <i>D. immitis</i> isolates were positive for <i>Wolbachia</i> endosymbionts of <i>D. immitis</i> belonging to the clade C DNA. <i>Acanthocheilonema reconditum</i> DNA was detected in 3 (3.1%) samples. Of these latter, one was found co-infected with the <i>Brugia</i> sp. genotype and the DNA of the clade D of the <i>Wolbachia</i> endosymbiont of <i>Brugia</i> species. This latter was also detected in two filarioid DNA-free samples. Finally, two samples were positive for <i>Cercopithifilaria bainae</i> genotype, which is distinct from those identified in Europe. The present study highlights the urgent need to implement chemoprophylaxis associated with anti-<i>Wolbachia</i> drugs to control these potential zoonoses.