Dogs wearing anti-leishmaniasis collars in a Brazil landscape.

Dog Collars vs. Leishmaniasis: A Surprising Weapon in Brazil's Fight Against the Disease

Elliot Brynn in Health & Wellness December 2025 • 4 min read.

"New research reveals how a simple dog collar could be a game-changer in preventing the spread of Leishmania infantum, offering hope for a safer, healthier future."

Visceral leishmaniasis (VL) is a major health concern worldwide, with a large number of cases concentrated in Brazil. This disease, caused by the parasite Leishmania infantum and spread by sandflies, poses a significant threat, especially to dogs, which act as major carriers in urban environments. Current control methods in Brazil involve a combination of tactics, but their effectiveness has been debated.

The usual strategies in Brazil's Visceral Leishmaniasis Control and Surveillance Program (VLCSP) include diagnosing and treating human cases, controlling sandfly populations with insecticides, and, controversially, euthanizing dogs that test positive for the disease. The problem? These measures haven't been very successful in significantly reducing the transmission of VL.

But what if there was a simple, more effective way to protect our furry friends and, in turn, protect ourselves? Researchers have been exploring innovative approaches, including special insecticide-impregnated dog collars. A recent large-scale study in Brazil investigated whether these collars, containing deltamethrin, could significantly reduce the incidence of L. infantum infections in dogs within a high-risk area.

How the Collars Made a Difference: The Study's Key Findings

Dogs wearing anti-leishmaniasis collars in a Brazil landscape.

The year-long intervention study focused on nearly 6,000 dogs in an area where VL is common. About 3,742 dogs were selected and divided into two groups: one wearing deltamethrin-impregnated collars and a control group without collars. The dogs were monitored over 12 months, with three check-up interventions.

The results were analyzed using two different methods: intention-to-treat and per-protocol. The intention-to-treat analysis, which includes all participants regardless of whether they fully complied with the study, showed a 48% reduction in L. infantum infections in the collared group. The per-protocol analysis, focusing only on dogs that consistently wore the collars, revealed an even greater effectiveness of 63%.

Intention-to-Treat Analysis: Demonstrated a 48% reduction in new infections with consistent collar use.
Per-Protocol Analysis: Showed an even higher effectiveness (63%) among dogs that consistently wore the collars throughout the study.
Reduced Incidence Rates: Lowered the number of new infections per year.
Safe Application: Showed no major side effects.

These findings highlight that while the collars provide protection, consistent and correct use is key to maximizing their impact. The data emphasizes the importance of uninterrupted use of deltamethrin-impregnated collars to increase protection against canine VL.

A Promising Step Forward in VL Control

This research offers a promising strategy for VL control in Brazil. The findings suggest that deltamethrin-impregnated dog collars can be a valuable tool, especially when used consistently, in reducing the spread of L. infantum among dogs. A relatively safe and simple to apply, these collars offer a practical way to lower infection rates and protect both animal and human populations.

Given the challenges faced by public health officials in implementing existing VL control measures, insecticide-impregnated collars offer a viable alternative to current strategies. While further research may be useful, this study supports integrating collar use into broader VL control programs for impactful results.

As pet owners, we can take a proactive step in protecting our dogs and community. By using these collars correctly and promoting responsible pet ownership, we can help reduce the burden of visceral leishmaniasis and create a healthier environment for all.

About this Article -

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This article is based on research published under:

DOI-LINK: 10.1371/journal.pone.0208613, Alternate LINK

Title: Effectiveness Of Deltamethrin-Impregnated Dog Collars On The Incidence Of Canine Infection By Leishmania Infantum: A Large Scale Intervention Study In An Endemic Area In Brazil

Subject: Multidisciplinary

Journal: PLOS ONE

Publisher: Public Library of Science (PLoS)

Authors: Wendel Coura-Vital, Gleisiane Gomes De Almeida Leal, Luana Araújo Marques, Aimara Da Costa Pinheiro, Mariângela Carneiro, Alexandre Barbosa Reis

Published: 2018-12-10

Everything You Need To Know

What is the main health issue being addressed?

The primary issue is Visceral leishmaniasis (VL), a significant health concern in Brazil caused by the parasite Leishmania infantum and spread by sandflies. This disease poses a threat to dogs, which act as major carriers, and subsequently, to humans. Current control methods, such as diagnosing and treating human cases, controlling sandfly populations with insecticides, and euthanizing infected dogs, have shown limited success in significantly reducing VL transmission. The study explores a new approach to increase the control of the disease.

What were the main findings of the study regarding the dog collars?

The study's key finding is that deltamethrin-impregnated dog collars can significantly reduce the incidence of Leishmania infantum infections in dogs. The results were analyzed using two methods: intention-to-treat and per-protocol. The intention-to-treat analysis showed a 48% reduction in new infections, while the per-protocol analysis revealed a 63% effectiveness among dogs consistently wearing the collars. The collars offer a promising strategy for VL control, especially when used consistently. Consistent and correct use is key to maximizing their impact. These collars offer a practical way to lower infection rates and protect both animal and human populations.

What is deltamethrin, and what role does it play in this context?

Deltamethrin is the insecticide used in the dog collars. The insecticide is a key component of the dog collars, which are designed to repel sandflies, the vectors of Leishmania infantum. By reducing the number of sandfly bites on dogs, the collars decrease the likelihood of the dogs contracting the parasite and, therefore, reduce the spread of VL. The deltamethrin-impregnated collars are a relatively safe and simple way to protect dogs from the disease.

How was the study conducted?

The study in Brazil involved nearly 6,000 dogs in a high-risk area for Visceral leishmaniasis. Approximately 3,742 dogs were selected and divided into two groups: one group wearing deltamethrin-impregnated collars and a control group without collars. The dogs were monitored over a year with three check-up interventions. This large-scale study was crucial to provide significant data, with two methods (intention-to-treat and per-protocol) used to analyze and measure the effectiveness of the dog collars.

What are the broader implications of this research?

The implications are significant as the research suggests a new approach to control Visceral leishmaniasis (VL). By reducing the spread of Leishmania infantum among dogs, these collars can contribute to protecting both animal and human populations. The findings provide a promising strategy for VL control in Brazil, and possibly other regions where this disease is prevalent. The use of deltamethrin-impregnated dog collars offers a practical and relatively safe intervention, that can lower infection rates when used correctly.