Cross sectional study reveals a high percentage of asymptomatic Plasmodium vivax infection in the Amazon Rio Negro Area, Brazil

• Published in: Revista do Instituto de Medicina Tropical de São Paulo Vol. 49; no. 3; pp. 159 - 164
• Main Authors: SUAREZ-MUTIS, Martha C, CUERVO, Patricia, LEORATTI, Fabiana M. S, MORAES-AVILA, Sandra L, FERREIRA, Antonio Walter, FERNANDES, Octavio, COURA, José Rodrigues
• Format: Journal Article
• Language: English
• Published: São Paulo Instituto de Medicina Tropical de São Paulo 01.06.2007; Instituto de Medicina Tropical de Sao Paulo; Instituto de Medicina Tropical
• Subjects: Adolescent; Adult; Aged; Animals; Antibodies, Protozoan - blood; Biological and medical sciences; Brazil - epidemiology; Child; Child, Preschool; Cross-Sectional Studies; DNA, Protozoan - analysis; Enzyme-Linked Immunosorbent Assay; Female; General aspects; Human protozoal diseases; Humans; Infectious diseases; Malaria; Malaria, Vivax - diagnosis; Malaria, Vivax - epidemiology; Male; Medical sciences; Middle Aged; Parasitic diseases; Plasmodium vivax - genetics; Plasmodium vivax - immunology; Polymerase Chain Reaction; Prevalence; Protozoal diseases; TROPICAL MEDICINE; South America; Brazil; America; Infection; Protozoa; Plasmodium vivax; Apicomplexa; Protozoal disease; Malaria; Cross sectional study; Brazilian Amazon; Tropical medicine; Asymptomatic infection; Asymptomatic; Parasitosis
• ISSN: 0036-4665; 1678-9946; 1678-9946; 0036-4665
• DOI: 10.1590/s0036-46652007000300005

A parasitological, clinical, serological and molecular cross-sectional study carried out in a highly endemic malaria area of Rio Negro in the Amazon State, Brazil, revealed a high prevalence of asymptomatic Plasmodium vivax infection. A total of 109 persons from 25 families were studied in five villages. Ninety-nine inhabitants (90.8%) had at least one previous episode of malaria. Serology showed 85.7% and 46.9% of positivity when P. falciparum antigens and P. vivax MSP-1, respectively, were used. Twenty blood samples were PCR positive for P. vivax (20.4%) and no P. falciparum infection was evidenced by this technique. No individual presenting positive PCR reaction had clinical malaria during the survey neither in the six months before nor after, confirming that they were cases of asymptomatic infection. Only one 12 year old girl presented a positive thick blood smear for P. vivax. This is the first description of asymptomatic Plasmodium infection in this area studied.