BackgroundThe physical characteristics of the environment influence the composition, distribution and behavior of the vectors and mammalian hosts involved in the transmission of visceral leishmaniasis (VL), thereby affecting the epidemiology of the disease. In Brazil, urbanization of human VL is a recent phenomenon and represents an issue of particular concern to local health authorities. The present study aimed to establish the degree of spatial dependency between canine and human VL in the municipality of Divinópolis, Minas Gerais, Brazil, and to identify priority risk areas in which stricter control measures should be implemented.MethodsThe selected canine population comprised 3,652 dogs distributed within 11 strata and 1,247 urban blocks. Serum samples were collected between March 2013 and February 2014. Serodiagnosis of dogs was performed using the enzyme-linked immunosorbent assay and the indirect fluorescent-antibody test. The blocks sampled for canine VL and the addresses of the 16 confirmed cases of human VL notified in Divinópolis during the period 2007–2013 were georeferenced. Spatial analysis of the data was performed using Kernel density estimation, Ripley’s bivariate K-function and directional distribution methods.ResultsThe overall prevalence of seropositive animals was 4.63% (range 3.95 - 5.31) (n =169) and varied in different strata between 0.9 (range 0.0 - 1.91) and 8.73% (range 5.65 - 11.81). A positive spatial dependency was detected between human and canine VL in which the occurrence of human cases of the disease tended to concentrate in locations that were close to areas with a higher incidence of canine VL. The priority risk area could be clearly distinguished from Kernel density estimation and standard deviational ellipse plots in which the human VL ellipse was totally enclosed within the canine VL ellipse.ConclusionsThe results presented herein will enable the Municipal Health Office of Divinópolis to devise a more effective management plan for human VL in which specific strategies would be applied to areas presenting different levels of risk. This spatial evaluation of leishmaniasis model could be applied in other urban areas of Brazil.
Background: The physical characteristics of the environment influence the composition, distribution and behavior of the vectors and mammalian hosts involved in the transmission of visceral leishmaniasis (VL), thereby affecting the epidemiology of the disease. In Brazil, urbanization of human VL is a recent phenomenon and represents an issue of particular concern to local health authorities. The present study aimed to establish the degree of spatial dependency between canine and human VL in the municipality of Divinópolis, Minas Gerais, Brazil, and to identify priority risk areas in which stricter control measures should be implemented. Methods: The selected canine population comprised 3,652 dogs distributed within 11 strata and 1,247 urban blocks. Serum samples were collected between March 2013 and February 2014. Serodiagnosis of dogs was performed using the enzyme-linked immunosorbent assay and the indirect fluorescent-antibody test. The blocks sampled for canine VL and the addresses of the 16 confirmed cases of human VL notified in Divinópolis during the period 2007-2013 were georeferenced. Spatial analysis of the data was performed using Kernel density estimation, Ripley's bivariate K-function and directional distribution methods. Results: The overall prevalence of seropositive animals was 4.63% (range 3.95 -5.31) (n =169) and varied in different strata between 0.9 (range 0.0 -1.91) and 8.73% (range 5.65 -11.81). A positive spatial dependency was detected between human and canine VL in which the occurrence of human cases of the disease tended to concentrate in locations that were close to areas with a higher incidence of canine VL. The priority risk area could be clearly distinguished from Kernel density estimation and standard deviational ellipse plots in which the human VL ellipse was totally enclosed within the canine VL ellipse. Conclusions: The results presented herein will enable the Municipal Health Office of Divinópolis to devise a more effective management plan for human VL in which specific strategies would be applied to areas presenting different levels of risk. This spatial evaluation of leishmaniasis model could be applied in other urban areas of Brazil.
Identification of factors associated with Leishmania infection in dogs is essential for targeting visceral leishmaniasis control actions. Thus, the present study analyzed some of these factors in a population of dogs in a Brazilian municipality, along with the limitations of control strategies implemented there. The association between the exposure variables and occurrences of infection was analyzed through logistic regression models. The disease control interventions were treated qualitatively. Out of the 755 animals examined, 13.6% (103/755) were seropositive. Of these, 23.3% (24/103) were asymptomatic and 76.7% (79/103) presented at least one clinical sign possibly associated with visceral leishmaniasis. With weak associations, purebred, shorthaired, over 5 years of age, male and large dogs were more prone to infection. The latter two variables formed the final regression model and the association with dog size was statistically significant. The control strategies developed presented limitations and a great number of seronegative dogs was culled. The data presented contribute towards better understanding of the dynamics of infection in canine visceral leishmaniasis and indicate that actions aimed towards adequate implementation of Visceral Leishmaniasis control program in Brazilian endemic areas should be prioritized.
Visceral Leishmaniasis by Leishmania infantum chagasi is an endemic zoonosis present in many areas of Brazil. This parasite needs reservoirs for maintenance of the infection and the presence of dogs in urban areas is a key factor for the spread of canine visceral leishmaniasis (CVL). The aim of this study was to report the first autochthonous case of CVL in the municipality of Iguatama, in west central region of Minas Gerais State. Dog infection by Leishmania infantum chagasi was confirmed in the municipality, previously considered as non-endemic area to CVL. The canine infection by Leishmania was confirmed by three immunological tests for antibodies: indirect immunofluorescence assay (IFA), rapid Dual Path Platform (DPP®) CVL immunochromatographic test, enzyme-linked immunosorbent assay (ELISA), and microscopic demonstration of Leishmania amastigotes in imprints of spleen and bone marrow stained by Giemsa. The species Leishmania infantum chagasi was confirmed by molecular diagnosis (PCR). Studies are being carried out, aiming to describe the importance and the prevalence of this disease in the region and factors associated with its transmission.
objectives To analyse the accuracy of American tegumentary leishmaniasis (ATL) diagnostic methods and evaluate the quality of the existing publications by means of a systematic review. methods Diagnostic tests evaluated in at least two studies with common reference standards were included in the sensitivity and/or specificity meta-analyses. Quality and susceptibility to bias were analysed using the QUADAS-2 and STARD tools. results The title and abstract of 3387 publications were evaluated after deduplication resulting from database searches. Thirty-eight studies were included in the review, and 26 of them had results inserted in meta-analyses. The diagnostic methods with the highest pooled sensitivity values were ELISA, polymerase chain reaction (PCR), indirect immunofluorescence reaction and Montenegro's intradermal reaction. Cytometry was assessed in only two studies and presented 100% sensitivity in both. Smear slide microscopy and histopathology showed low pooled values of sensitivity. For specificity, the highest pooled values were identified for PCR. High values were also identified for ELISA, except for studies in which the reference standard for defining negative participants included individuals with Chagas' disease or paracoccidioidomycosis, which also occurred for cytometry. IFR had lower specificities than ELISA. There was a predominance of case-control designs of phase 1 or 2 and only four studies were strongly recommended as evidence generators. Several reference standards were adopted, and different methods were assessed in a small number of studies. conclusion PCR showed the highest accuracy for the diagnosis of ATL, and its use should be encouraged in clinical practice. ELISA is recommended for the screening of suspected individuals, but the possibility of cross-reactions should be considered. New validation studies for the tests evaluated in few publications and studies of phase 3 with appropriate methods are needed.
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