Efficacies of insecticide dog collars against visceral leishmaniasis in low and high-income areas and the effects for non-collared neighbor dogs

• Published in: Acta tropica Vol. 235; p. 106626
• Main Authors: Matsumoto, Patricia Sayuri Silvestre, Taniguchi, Helena Hilomi, Pereira, Virgínia Bodelão Richini, Hiramoto, Roberto Mitsuyoshi, Seviero Rampazzi, Karla Letícia, de Raeffray Barbosa, José Eduardo, Puci Neto, Roldão Antonio, Camprigher, Valéria Medina, de Barros Cortez, Luiz Ricardo Paes, Rahaman, Khan Rubayet, Novak, Mathew, Tolezano, José Eduardo
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.11.2022
• Subjects: Deltamethrin-impregnated collars (DMC); Dogs; Geoprocessing; Inequality; Insecticide collars; Low-income; Neglected diseases; Public health; Spatial analysis; Surveillance; Deltamethrin-impregnated collars (DMC); Geoprocessing; Neglected diseases; Surveillance; Low-income; Dogs; Spatial analysis; Insecticide collars; Public health; Inequality
• DOI: 10.1016/j.actatropica.2022.106626
• ISSN: 0001-706X

•4% Deltamethrin-Impregnated Collared (DMC) dogs were successfully protected (63%) against canine visceral leishmaniasis (CVL) compared to control dogs.•DMC showed higher efficacy in low-income areas (76%) than in the high-income ones (45%).•There is no indirect protection of DMC for non-collared dogs living nearby DMC dogs.•DMC dogs may repeal Lutzomyia longipalpis while non-protected neighbor dogs attract them, increasing the seroconversion of CVL by the indirect effect of DMC.•Innovative technological measures such as spatial analysis, real-time data collection, and instant messages to inform the research results for people can prevent and promote health and help create the One Health approach. Previous studies demonstrated that insecticide collars are highly effective in reducing canine visceral leishmaniasis (CVL); however, it is unclear if the efficacy differs by socioeconomic conditions across diverse communities. This study aimed fourfold: (i) to evaluate the protection of 4% impregnated deltamethrin collared (DMC) dogs in different areas of an endemic city for visceral leishmaniasis (VL); (ii) to analyze socioeconomic variables with the seroconversion rates; (iii) to analyze the indirect effect of DMC on untreated dogs in areas of intervention; and, (iv) to evaluate the potential transmission to other dogs in the same household when one positive dog is present. The study employed the municipality of Bauru, São Paulo, Brazil, as the area of interest and used Geographic Information System tools to fit binary logistic regression models.  Dogs were divided into three cohort studies: intervention with DMC (I), indirect effect of DMC (IE), and control (C). Pre-intervention, lower mean income was associated with higher rates of CVL and a 142% increase in the odds of transmission (OR = 1.42, p-value = 0.001, CI 1.14,1.77). Post-intervention, lower-income areas depicted greater efficacy (76%) than higher-income areas (45%). The overall efficacy of DMC in preventing CVL was 63%; however, seroconversion rates were higher for IE (6.02%) than C (3.78%), revealing the failure of the indirect protection of DMC to manage the spread of the disease among the general non-wearing DMC canine population living in the same area. The protected dogs may repel the vectors, and non-protected dogs attract them, creating a higher transmission rate for non-protected dogs. Greater seroconversion was observed for living with an infected dog (10.20% in IE and 8.75% in C) than for the indirect effect of DMC, demonstrating the social burden of CVL. Overall, uncollared dogs have three times higher odds of being infected with CVL than DMC dogs (p < 0.005), and uncollared dogs living with (an) infected dog(s) in the same household can reach 3.5 times higher odds than those living with negative ones (p < 0.005). The results may assist in enhancing public policies and minimizing inequality in low and middle-income countries that suffer from neglected diseases such as VL. [Display omitted]