Selamectin for the prevention of canine Dirofilaria immitis infection: field efficacy in client-owned dogs in a high risk area

Abstract

BackgroundDog owners and veterinarians in small animal practices began to waive prevention of canine heartworm disease after heartworm infections seemed to have disappeared in Brazil. After 2013, infection rates rebounded, and an evaluation of the efficacy of chemoprophylactic drugs became necessary. Included in this re-evaluation was the efficacy of selamectin in client-owned dogs residing in a high infection-risk area.MethodsThe preventive efficacy of selamectin was evaluated by the topical application of selamectin to 24 client-owned dogs at the recommended rate (minimum of 6 mg/kg) by a veterinarian monthly for 36 months. Blood samples were collected before the first treatment and at the end of the study for testing to detect microfilariae by the modified Knott’s test and Dirofilaria immitis antigens using a commercial antigen test. Exposure to risk of heartworm infection was confirmed by the presence of infection in dogs living in low-income communities within a 2 km radius from the homes of dogs in the study. The dogs were managed according to routine practice by the owners within each household throughout the study.ResultsAll dogs tested negative by both tests after receiving topical treatment with selamectin monthly for 36 months. Testing of 204 dogs from the communities confirmed the presence of heartworm in the area by detection of microfilariae or D. immitis antigen in 44 dogs (21.6 %).ConclusionsTopical selamectin was 100 % effective for D. immitis prevention in 24 dogs that received monthly treatments by a veterinarian. Detection of heartworm infections in untreated dogs in the area suggests that clients need to be better informed regarding the prevalence of D. immitis and the importance of maintaining regular preventive treatments.

Gusano del corazón ectópico en un paciente canino asintomático: Reporte de caso

“…A estabilidade da paciente, frente aos achados clínicos normalizados, infere e reforça a importância e a natureza insidiosa da doença (Nelson et al, 2020), trazendo ainda mais atenção, e necessidade de testes diagnósticos para detecção de forma precoce da doença (Moraes et al, 2016).…”

Field Implementation of a Monthly Multi-Modal Prophylactic Strategy (Dinotefuran-Permethrin-Pyriproxyfen and Milbemycine Oxime-Praziquantel) Against Canine Vector-Borne Diseases in Corsica

“…For obvious ethical reasons, the demonstration of MMP efficacy was based on a comparison with real-life preventive strategies (treated with several existing approved products irrespective of the treatment period or the number of dogs in the subgroups) as an active control instead of an untreated control. The active control groups are often used to demonstrate the efficacy of new treatments on the field [28][29][30].…”

Evaluation of Microfilaricidal Efficacy of Doxycycline, Ivermectin and Selamectin in Dogs Naturally Infected with Dirofilaria repens

“…The animal remained negative for D. immitis microfilariae during a follow-up period of 180 days and combined therapy was found effective. Moraes-da-Silva et al, (2016) conducted a study to evaluate the efficacy of selamectin topical application @ 6 mg/kg b. wt. to dogs living in a high risk area in Brazil.…”

“…Many researchers used different therapeutic agents against D. immitis and D. repens infection in dogs either alone or in combination with other drugs (Lok et al, 2005;Fok et al, 2010;Genchi et al, 2010;Razi Jalali et al, 2011;Rocconi et al, 2012;Genchi et al, 2013;McCall et al, 2014;Chandrashekar et al, 2014;Frangipane et al, 2016 andMoraes-da-Silva et al, 2016) and opined that, the combined use of microfilaricide and adulticide drugs are effective compared with either microfilaricide or adulticide drugs alone against filarial infections in dogs.…”