Concurrent triple parasitic infection (Ctenocephalides canis, Rhipicephalus sanguineus, and Toxocara canis) in a domestic dog from Bangladesh: clinical management and zoonotic implications

Abstract

Mixed parasitic infections are prevalent in dogs, often leading to significant clinical issues and posing zoonotic risks to humans. Dogs can simultaneously harbor ectoparasites such as fleas and ticks and endoparasites such as gastrointestinal nematodes. These parasites can induce dermatological and gastrointestinal disorders and serve as vectors or reservoirs for zoonotic infections. This case report describes a rare triple parasitic co-infection involving Ctenocephalides canis, Rhipicephalus sanguineus, and Toxocara canis in a domestic dog in Bangladesh and highlights the diagnostic approach and effective treatment strategy. A 2-year-old male local breed dog presented to the veterinary clinic at Bangladesh Agricultural University, Mymensingh, Bangladesh, exhibiting severe pruritus, reduced body condition score, and enteric signs. Parasites were collected and identified through gross examination and detailed morphological analysis under a stereomicroscope (Olympus SZ61, Olympus Corporation, Tokyo, Japan). Key diagnostic features included cervical alae in T. canis, genal and pronotal combs in C. canis, and a hexagonal basis capitulum in R. sanguineus. Treatment consisted of an oral combination of sarolaner (1200 µg/kg), moxidectin (24 µg/kg), and pyrantel pamoate (5000 µg/kg), accompanied by supportive therapy and environmental control measures. Morphological examination identified 35 adult Ctenocephalides canis, 12 adult Rhipicephalus sanguineus and 4 adult Toxocara canis, thereby indicating a concurrent triple infection. Following treatment, clinical improvement was observed within 48 h, characterized by a marked reduction in pruritus and improved appetite. A follow-up examination at 14 days revealed no visible ectoparasites and a negative fecal flotation test for T. canis eggs. Complete clinical recovery was recorded during the 30-day follow-up period. This case underscores the clinical and zoonotic significance of mixed parasitic infections in dogs. Routine parasitic screening and preventive measures are crucial within a One Health framework to minimize zoonotic transmission risks.