Malaria epidemiology in low-endemicity areas of the Atlantic Forest in the Vale do Ribeira, São Paulo, Brazil

• Published in: Acta tropica 2006-11, Vol.100 (1), p.54-62
• Main Authors: Curado, Izilda, dos Santos Malafronte, Rosely, de Castro Duarte, Ana Maria Ribeiro, Kirchgatter, Karin, Branquinho, Maria Stela, Bianchi Galati, Eunice Aparecida
• Format: Article
• Language: English
• Subjects: Adult; Animals; Antibodies, Protozoan - blood; Asymptomatic malaria; Atlantic Forest; Biological and medical sciences; Brazil; Brazil - epidemiology; Circumsporozoite protein; DNA, Protozoan - analysis; Endemic Diseases; Enzyme immunosorbent assay; Enzyme-Linked Immunosorbent Assay; Epidemiology; Female; Fluorescent Antibody Technique, Indirect; General aspects; Human protozoal diseases; Humans; Indirect immunofluorescent assay; Infectious diseases; Malaria; Malaria - epidemiology; Malaria - parasitology; Male; Medical sciences; Parasitic diseases; Plasmodium - classification; Plasmodium - growth & development; Plasmodium - immunology; Plasmodium falciparum; Plasmodium malariae; Plasmodium vivax; Polymerase Chain Reaction; Prevalence; Protozoal diseases; Protozoan Proteins - immunology; Public health. Hygiene; Public health. Hygiene-occupational medicine; Trees
• ISSN: 0001-706X; 1873-6254
• DOI: 10.1016/j.actatropica.2006.09.010

We describe a seroepidemiological survey of malaria prevalence in two areas of low endemicity: Intervales State Park and Alto Ribeira State Tourist Park (PETAR). Both are located in the Vale do Ribeira in the state of São Paulo, Brazil. In this study, 318 subjects from both areas had their blood analyzed for the presence of malaria parasites by thin and thick blood smears. One hundred and sixty-three (51.2%) of the subjects were from Intervales State Park and 155 (48.7%) were from PETAR. We analyzed all the samples by indirect immunofluorescent assay (IFA) to detect antibodies against asexual forms of Plasmodium vivax and Plasmodium malariae and enzyme immunosorbent assay (ELISA) to detect the presence of antibodies against circumsporozoite proteins (CSP) from P. vivax VK210, human P. vivax-like/ Plasmodium simiovale, P. vivax VK247 and Plasmodium brasilianum/ P. malariae. The presence of Plasmodium species was detected by polymerase chain reaction (PCR). Eighteen of the subjects analyzed had positive IFA results for IgM against P. malariae antigens, and three others were positive for P. vivax antigens. Positivity of IgG antibodies against P. vivax detected by IFA was high in samples from both Intervales State Park and PETAR (32.0% and 49.0%, respectively), while positivity for P. malariae was lower (16.0% and 19.3% in Intervales State Park and PETAR, respectively). ELISA tests showed a higher prevalence of antibodies against P. vivax VK210 (35.0%) in samples from Intervales State Park and against human P. vivax-like (29.7%) in samples from PETAR. PCR reactions revealed the presence of parasites in several of the samples analyzed. In Intervales State Park, one subject was infected by P. malariae and two by Plasmodium falciparum, while in PETAR, one subject was positive for P. falciparum and three for both P. falciparum and P. vivax parasites. The areas where these parks are located belong to the Atlantic Forest habitat, and inhabitants frequently, see monkeys. Our data suggest that monkeys may constitute a natural reservoir for malaria in both areas.