First identification of Strongyloides stercoralis infection in a pet dog in Argentina, using integrated diagnostic approaches

Abstract

Background Strongyloides stercoralis is a soil-transmitted intestinal nematode with a complex life cycle that primarily affects humans, non-human primates, dogs, and occasionally cats. This study presents, to the best of our knowledge, the first case of S. stercoralis infection and its genotyping in a domestic dog from Argentina. Methods The patient was a female wired-haired Teckel dog exhibiting recurrent coughing. Coproparasitological analysis using the Baermann technique revealed the presence of rhabditiform larvae morphologically compatible with S. stercoralis. To confirm this finding, molecular diagnosis (18S ribosomal RNA) and analysis of the cox1 gene were performed. Results We identified a haplotype (HP20) that has previously only been related to S. stercoralis infection in dogs, but was found in the present study to be highly related to the haplotype (HP16) of a zoonotic variant and divergent from those previously described from human patients in Argentina. Furthermore, unlike in human cases following treatment with ivermectin, the dog was negative after moxidectin treatment according to polymerase chain reaction of the sampled faeces. Conclusions This case report shows the importance of further investigation into potential transmission events and prevalences of S. stercoralis in dogs and humans in South America. The results reported here should also encourage future work that examines different scenarios of infection with S. stercoralis in dogs and humans with the aim of integrating clinical management, diagnosis, treatment and follow-up strategies in the quest for new approaches for the treatment of this disease in animals and humans. The findings support the adoption of a One Health approach, which recognizes the interconnectedness between animal and human health, in addressing parasitic infections such as strongyloidiasis. Graphical Abstract

Strongyloides stercoralis in two dogs from a household in temperate Australia

“…In humans, ivermectin is considered the most efficacious drug for the treatment of S. stercoralis with cure rates of up to 97% in asymptomatic patients with a 2 day course, with longer courses recommended for patients with hyperinfection 29 . In dogs, there are a small number of publications on treatments for S. stercoralis based on single cases 15,19 and small case series 12,14,17,21,30 . Fenbendazole either used alone orally or in combination with moxidectin/ imidocloprid topically on the skin appeared inconsistent in eliminating infection in all dogs, 12,14,17 with a single case report utilising oral moxidectin with success 19 .…”

“…In dogs, there are a small number of publications on treatments for S. stercoralis based on single cases 15,19 and small case series 12,14,17,21,30 . Fenbendazole either used alone orally or in combination with moxidectin/ imidocloprid topically on the skin appeared inconsistent in eliminating infection in all dogs, 12,14,17 with a single case report utilising oral moxidectin with success 19 . Milbemycin has also been reported to have some efficacy although also inconsistent 18 .…”

“…Disease in dogs is asymptomatic and self‐limiting in most cases with clinical disease presenting in younger dogs with diarrhoea, with or without weight loss, with more severe clinical signs involving skin lesions and bronchopneumonia 2,10,12–19 . Hyperinfection in immunosuppressed dogs has been reported following the use of glucocorticoids for suspected inflammatory bowel disease 15,20 .…”