Effectiveness of the Brazilian Visceral Leishmaniasis Surveillance and Control Programme in reducing the prevalence and incidence of Leishmania infantum infection

Abstract

BackgroundControl strategies adopted by the Brazilian Visceral Leishmaniasis Surveillance and Control Programme (VLSCP) include identifying and culling seropositive infected dogs, early diagnosis and treatment of human cases, chemical control of the vector and population awareness. This study evaluated the effectiveness of the VLSCP on the prevalence and incidence rates of Leishmania infantum in children residing in areas under different VLSCP intervention times.MethodsA quasi-experimental epidemiological study with a panel (two cross-sectional) and a concurrent cohort was performed in three areas of Belo Horizonte, southeast Brazil. The first cross-sectional study (I) was carried out with 1875 children, 478 of which were enrolled in the cohort study. In the second cross-sectional study (II), 413 additional children were included, totalizing 891 children. Laboratory diagnosis was performed by ELISA-rK39. Analyses included multilevel logistic and Poisson regression models.ResultsThe incidence rates of L. infantum infection were: 14.4% in the area where VLSCP intervention was initiated in 2006 (AI2006); 21.1% in the area where intervention was initiated in 2008 (AI2008); and 11.6% in the area where intervention was initiated in 2010 (AI2010 - control area). A follow-up period of 24 months showed that the persons-time incidence rates in AI2006, AI2008, and AI2010 were: 6.2/100, 10/100, and 5.6/100 persons/24 months, respectively. The final prevalence rates of infection (cross-sectional II - in 2012), compared to the initial rates (cross-sectional I - in 2010), increased 83.7% in AI2006, 74.1% in AI2008, and decreased 5% in AI2010. Analysis of the effectiveness revealed that children residing in AI2008 are more likely to be infected (OR = 1.84; 95% CI: 1.06-3.23) and present a higher risk of infection (IRR = 1.76; 95% CI: 1.05-2.95) compared to those in AI2010. No statistically significant differences were observed in asymptomatic infection (OR and IRR) in AI2006 compared to AI2010.ConclusionsThe VLSCP was not effective at controlling L. infantum infection in areas where interventions had respectively been carried out for six and four years. However, it is unclear what the consequences in terms of human infection and diseases would be in the absence of the VLSCP. Efforts to improve the effectiveness of control measures remain a necessary priority.Electronic supplementary materialThe online version of this article (10.1186/s13071-018-3166-0) contains supplementary material, which is available to authorized users.

A cross-sectional approach including dog owner characteristics as predictors of visceral leishmaniasis infection in dogs

“…(4) Dogs are considered the main source of infection in urban areas and this represents a major challenge for the implementation of control measures, resulting in the euthanasia of seropositive animals in an attempt to reduce the risk of transmission to humans. (5) However, euthanasia has been increasingly rejected due to the appreciation of pets, especially dogs. (6,7) In addition, its ineffectiveness has raised concerns.…”

Prospection of immunological biomarkers for characterization and monitoring of asymptomatic Leishmania (Leishmania) infantum infection

“…This is a cohort study conducted in 2013 with 179 children aged 1–10 years old (mean age: 5 years old) selected from a cross-sectional study carried out in 2012 to evaluate the prevalence of asymptomatic L. infantum infection in an endemic area of Belo Horizonte, the capital of the state of Minas Gerais, Brazil. Among those, 141 children were diagnosed positive in at least one serological test (ELISA using recombinant antigen K39 and/or soluble L. infantum antigen performed in peripheral blood samples absorbed on filter paper), while 38 children were diagnosed negative in the two tests (da Rocha et al ., 2018).…”

Nonconventional opponents: a review of malaria and leishmaniasis among United States Armed Forces

“…Canine Leishmaniasis (CanL) is a common veterinary problem worldwide, with recent prevalence estimates as high as 25–80% (Michel et al., 2011; Akhtardanesh et al., 2017; Baneth et al., 2017; Guven et al., 2017; Ruh et al., 2017; Al-Bajalan et al., 2018; Monteiro et al., 2018). Brazil is known to be especially affected (Borja et al., 2016; Torres-Guerrero et al., 2017; Da Rocha et al., 2018; Melo et al., 2018), with published reports highlighting increases in diagnoses and advocating for better public health strategies to be focused specifically on dogs (Camargo & Langoni, 2006; Lima et al., 2010). The armed forces regularly use military working dogs (MWD) for special operations, including abroad in Leishmania -endemic regions.…”