Molecular detection of filarioid worms in dogs in Nigeria, West Africa

Abstract

The filarioid worm Dirofilaria repens has long been reported in dogs in Nigeria. Recent studies however, did not only report increased prevalence of D. repens but also the presence of Dirofilaria immitis. The classical diagnostic methods used in these studies have low sensitivity. Therefore, we screened 197 canine blood samples from seven states in Nigeria, using a highly sensitive and specific High Resolution Melt Real Time PCR and sequencing, to determine the prevalence and species of filarial worms infecting Nigerian dogs. Only one (0.5%) of the 197 samples screened was positive and showed a melt curve similar to Acanthocheilonema reconditum. Nevertheless, the sequence of this positive sample had only 94% similarity to its first GenBank match, a A. reconditum (JF461460.1). This could be a new filarioid species or a variant of an existing species and deserves further investigation. The low prevalence reported herein is in discrepancy with previous reports that showed the frequent presence of canine filariasis in Nigeria. A large scale survey is needed of filarioids infecting dogs in Nigeria, using highly sensitive and specific methods, to identify the present species and provide a baseline data on their national prevalence and geographic distribution.