Emergence of Ancylostoma caninum parasites with the benzimidazole resistance F167Y polymorphism in the US dog population

Unambiguous identification ofAncylostoma caninumandUncinaria stenocephalain Australian and New Zealand dogs from faecal samples

“…Our small‐scale study demonstrated absence of detectable alleles in A. caninum and U. stenocephala associated with benzimidazole resistance. Recently Venkatesan et al 11 demonstrated widespread β‐tubulin F167Y(TTC > TAC) mutation present in 50% (156/314) dogs infected with A. caninum using the ‘nemabiome’ approach 11 and Leutenegger et al 10 in 11% (54/511) using A. caninum allele‐specific qPCR tests. In AU6 A. caninum , the persistent shedding of A. caninum , despite repeated treatment reported by the owner, is therefore attributed to re‐infection or non‐compliance.…”

“…9 Recently two studies investigated the extent of benzimidazole resistance across the United States and one found over half of the A. caninum isolates had resistance allele frequency higher than 50% of that of the isotype-1 β-tubulin F167Y. 10,11 Besides A. caninum, Australian dogs are hosts for three other hookworms, including the tropical hookworms Ancylostoma ceylanicum and Ancylostoma braziliense, and the cooler climate hookworm Uncinaria stenocephala. Dogs in New Zealand are traditionally considered to be only infected by U. stenocephala, because A. caninum was assumed to be restricted to racing greyhounds.…”

“…In Australia, A. caninum resistance to pyrantel embonate was experimentally confirmed already in 2008 and the authors urged “for greater vigilance and more judicious use of anthelmintics in small animal practice” 9 . Recently two studies investigated the extent of benzimidazole resistance across the United States and one found over half of the A. caninum isolates had resistance allele frequency higher than 50% of that of the isotype‐1 ‐tubulin F167Y 10,11 . Besides A. caninum , Australian dogs are hosts for three other hookworms, including the tropical hookworms Ancylostoma ceylanicum and Ancylostoma braziliense , and the cooler climate hookworm Uncinaria stenocephala .…”

Reflecting on the past and fast forwarding to present day anthelmintic resistant Ancylostoma caninum–A critical issue we neglected to forecast

“…Approximately fifteen years ago Kopp et al (2007) described a pyrantel-resistant isolate in Australia. Within the last few years, A. caninum genetic markers for benzimidazole drug-resistance became available ( Furtado et al, 2014 , Schwenkenbecher and Kaplan, 2009 , Venkatesan et al, 2023 ) and can be used to evaluate the distribution of fenbendazole resistance in A. caninum in USA dogs ( Jimenez Castro et al, 2021 , Leutenegger et al, 2023 ). Venkatesan et al (2023) and Leutenegger et al (2023) demonstrated it is no longer just a “Greyhound problem,” as the fenbendazole resistance genetic marker in A. caninum is now widely distributed in USA pet dogs.…”

“…Within the last few years, A. caninum genetic markers for benzimidazole drug-resistance became available ( Furtado et al, 2014 , Schwenkenbecher and Kaplan, 2009 , Venkatesan et al, 2023 ) and can be used to evaluate the distribution of fenbendazole resistance in A. caninum in USA dogs ( Jimenez Castro et al, 2021 , Leutenegger et al, 2023 ). Venkatesan et al (2023) and Leutenegger et al (2023) demonstrated it is no longer just a “Greyhound problem,” as the fenbendazole resistance genetic marker in A. caninum is now widely distributed in USA pet dogs. In the USA, there are at least two MADR A. caninum published case reports, characterized through both in vivo and in vitro studies ( Jimenez Castro et al, 2019 ; Kitchen et al, 2019 ; Jimenez Castro et al, 2020b ).…”