High seroprevalence and peripheral spatial distribution of visceral leishmaniasis among domestic dogs in an emerging urban focus in Central Brazil: a cross-sectional study

Abstract

The Brazilian municipality of Rondonópolis is an emerging urban focus of intense transmission of visceral leishmaniasis (VL), where few investigations have addressed canine reservoirs. This study assessed the seroprevalence and spatial distribution of canine visceral leishmaniasis (CVL) in the urban area of Rondonópolis. A CVL serosurvey was conducted between October 2016 and February 2017 using an immunochromatographic rapid test and enzyme-linked immunosorbent assay. Domestic dogs were sampled from 25 heterogeneous regions previously defined by the Spatial 'K'luster Analysis by Tree Edge Removal algorithm, which considered the socioeconomic and environmental features from the last demographic census. The CVL spatial distribution was analyzed by kernel density estimation (KDE) and spatial scan statistic. All the autochthonous human VL cases reported between 2014 and 2016 were georeferenced. Of the 600 dogs tested, 115 were seropositive in both tests. The overall CVL prevalence was 19.2% (95%CI: 16.1-22.3%), which varied widely among the evaluated regions (0.0-35.1%). Almost 25% of the sampled households (n = 405) had at least one infected dog. KDE demonstrated that positive CVL households were concentrated in the peripheral areas of the city. Spatial scan statistics detected a spatial cluster with significantly low CVL prevalence in the central region (relative risk = 0.37; p = 0.04), where only one human VL case was reported. Thus, we demonstrated a high prevalence of CVL in domestic dogs from diverse socioeconomic and environmental urban contexts in Rondonópolis. The CVL cases were peripherally distributed and occurred more frequently in areas that had reported human VL.

High levels of serum glycans monovalent IgG immune complexes detected by dissociative ELISA in experimental visceral leishmaniasis

“…Leishmania (Leishmania) infantum chagasi causes VL in Latin American countries, transmitted to a mammalian host by phlebotomine sandflies. This disease has great medical and veterinary importance, and is considered an anthropozoonosis; among its hosts, the domestic dog plays a prominent role in the transmission cycle, as the main reservoir responsible for the spread of the disease among the human population …”

“…This disease has great medical and veterinary importance, and is considered an anthropozoonosis; among its hosts, the domestic dog plays a prominent role in the transmission cycle, as the main reservoir responsible for the spread of the disease among the human population. 2 Clinical manifestations of VL may present in different forms, ranging from asymptomatic to lethal. 3…”

Abordagens Geográfica da Vigilância, Prevenção e Promoção da Saúde

“…Isso representou outra alteração considerável no panorama da LV na área de estudo, uma vez que a região metropolitana da capital Cuiabá havia liderado os registros entre 1998 e 2005 (MESTRE; FONTES, 2007). A elevada ocorrência de LV em Rondonópolis parece estar associada ao intenso processo de crescimento populacional e descontrolada ocupação do espaço geográfico com formação de áreas com marcantes diferenças intraurbanas recentemente visualizados no município (CARVALHO et al, 2018;LUZ et al, 2017;LUZ et al, 2018). Aparentemente, isso pode ter favorecido a adaptação dos insetos vetores na área urbana, que juntamente com a presença de reservatórios domésticos e seres humanos susceptíveis, favoreceu a instalação de ciclos de transmissão .…”

“…Cabe ressaltar que existência de áreas com características rurais dentro dos espaços urbanos, bem como a formação de áreas socioeconomicamente desfavorecidas com precariedade da infraestrutura sanitária, dificuldade de acesso aos serviços de saúde e desnutrição, já foram apontadas como hipóteses plausíveis para a ocorrência da epidemia de LV em diversas localidades brasileiras (ARAÚJO et al, 2013;COSTA, 2008;ROCHA et al, 2018). De fato, Carvalho et al (2018) demonstraram a sobreposição descritiva de áreas quentes para a LV canina e a doença humana nas zonas periféricas do município de Rondonópolis, que por sua vez caracterizam-se como áreas mais pobres.…”

First autochthonous case of canine visceral leishmaniasis in Rondônia, Brazil, a region with no history of visceral leishmaniasis

“…No cases have been recorded in the Rondônia State prior to this report. Rondonópolis City (approximately 200km from Cacoal), is an emerging urban focus of intense transmission of visceral leishmaniasis (VL); its reported prevalence of CVL is 19.2% 2 .…”