Sustained Presence of Cutaneous Leishmaniasis in Urban Manaus, the Largest Human Settlement in the Amazon

Abstract

The Amazon is responsible for approximately 40% of the American tegumentary leishmaniasis (ATL) in Brazil. Herein the sustained presence of ATL in Manaus, the largest settlement in the Amazon, was investigated. Records of notification of historic cases, and data from cases prospectively enrolled in the Tropical Medicine Foundation of the Amazonas State were used. Geographic coordinates of prospective patients' living sites were used to detect inner-city clusters of ATL. Infecting Leishmania species was determined by polymerase chain reaction. Among prospectively enrolled subjects, 94.8% were infected with Leishmania (Viannia) guyanensis, 76.7% were male, 30.2% were 0-20 years old, and 69.8% had an urban residence. Historic cases showed a profile similar to that of prospectively enrolled subjects. Several clusters of ATL, widely distributed within the city of Manaus, could be detected. In conclusion, there was a high frequency of disease in young age groups and cases clustered in urban neighborhoods. It cannot be determined from these data whether transmission of these cases occurred within or outside the city of Manaus.

Figure 1.

Representative photograph of an agarose gel showing electrophoretic patterns of Leishmania (Viannia) guyanensis and Leishmania (Viannia) braziliensis HSP-70 polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP). Reactions were performed as described in references., MW = molecular weight markers; Lg = L. (V.) guyanensis; Lb = L. (V.) braziliensis.

Figure 2.

Age distribution of 172 cases of American tegumentary leishmaniasis (ATL) diagnosed in the dermatology clinic of Tropical Medicine Foundation of the Amazonas State (FMTAM), Manaus, between January 2008 and August 2010.

Figure 3.

Distribution of American tegumentary leishmaniasis (ATL) cases within the city of Manaus. (A) Composite image showing the distribution of urban ATL cases diagnosed in the dermatology clinic of Tropical Medicine Foundation of the Amazonas State (FMTAM) between January 2008 and August 2010. Polygons outlined by black lines in the satellite photograph correspond to neighborhoods of Manaus. Green areas in color picture and dark gray areas in the black and white geo-referenced image correspond to vegetation. Red, light gray, and white areas correspond to populated districts. Yellow dots represent the homes of ATL patients. Yellow circle surrounds the major cluster of observed ATL cases, located in the Cidade Nova neighborhood. (B) Kernel analysis identifying clusters of cases represented by shades of yellow, red, and purple. Progression of shading from yellow to red to purple represents increasing density of clustered cases. Yellow circle surrounds the major cluster of ATL cases in the Cidade Nova neighborhood.

Figure 4.

Distribution of seven representative cases found at the center of the major cluster of American tegumentary leishmaniasis (ATL) patients in Cidade Nova neighborhood within the yellow circle from Figure 3A. Green areas correspond to vegetation. Yellow dots represent the homes of ATL patients.