Drug resistance

Praziquantel

Population

Cestode infections

Veterinary medicine

Biology

Microbiology

Helminths

Immunology

Schistosomiasis

Pyrantel

Dipylidium caninum

Anthelmintic

Medicine

Environmental health

American Journal of Tropical Medicine and Hygiene

Dipylidium caninum is a cosmopolitan cestode infecting dogs, cats, and humans. Praziquantel is a highly effective cestocidal drug and resistance in adult cestodes has not been reported. From 2016 to 2018, a population of dogs with cestode infections that could not be eliminated despite multiple treatments with praziquantel or epsiprantel was identified. Cases of D. caninum were clinically resistant to praziquantel and could not be resolved despite increasing the dose, frequency, and duration of treatment. Resistant isolates were identified and characterized by sequencing the 28S, 12S, and voltage-gated calcium channel beta subunit genes. Cases were only resolved following treatment with nitroscanate or a compounded pyrantel/praziquantel/oxantel product. Clinicians should be aware of this alarming development as treatment options for cestodes are limited in both human and veterinary medicine.

Praziquantel Resistance in the Zoonotic Cestode Dipylidium caninum