Can P-glycoprotein and β-tubulin polymorphisms be used as genetic markers of resistance in Dirofilaria immitis from Rio de Janeiro, Brazil?

Abstract

ObjectiveDirofilaria immitis, the causative agent of canine heartworm infection, is worldwide the most important filarid to affect domestic dogs. Prevention of this infection is done by macrocyclic lactones, but some reports on the lack of efficacy have been published. Although the actual cause of resistance is unknown, single nucleotide polymorphisms (SNPs) on a P-glycoprotein ABC transporter and β-tubulin genes have been pointed out as candidates for genetic markers of resistance. We conducted a survey to verify the presence of these suggested genetic markers in microfilariae from 30 naturally infected dogs under macrocyclic lactones treatment living in an endemic area in the state of Rio de Janeiro.ResultsThe analysis of these specific SNPs demonstrated no sign of polymorphism on the P-glycoprotein loci, while 72 and 48% of the samples were polymorphic to the first and second SNPs on β-tubulin loci, respectively. This work demonstrates that the P-glycoprotein position 11 and 618 were not polymorphic and, therefore, not suitable as a genetic marker of resistance in Rio de Janeiro whereas both β-tubulin loci were polimorphic. This work points out the difficulty of finding a universal genetic marker for resistance.Electronic supplementary materialThe online version of this article (10.1186/s13104-018-3259-z) contains supplementary material, which is available to authorized users.

Genome structure and population genomics of the canine heartwormDirofilaria immitis

“…In the USA, reports describing the loss of efficacy of ML for the treatment of D. immitis infections have been increasing in frequency since 1998 (Hampshire, 2005) and confirmed by the isolation of an ML-resistant D. immitis isolate in 2014 (Pulaski et al, 2014). Several studies have attempted to define genetic variants associated with resistance to be used to monitor its emergence and spread (Bourguinat et al, 2017(Bourguinat et al, , 2016(Bourguinat et al, , 2011a(Bourguinat et al, , 2011bCurry et al, 2022a;Mani et al, 2017;Sanchez et al, 2020;Willi et al, 2018). The most promising of these studies used pooled worm .…”