Seasonal variation of anti-resa/Pf155 Plasmodium falciparum antibodies in three localities from the state of Amapá, Brazil Variação sazonal de anticorpos anti-RESA/Pf155 de Plasmodium falciparum em três localidades do Estado do Amapá, Brasil

• Published in: Revista do Instituto de Medicina Tropical de São Paulo
• Main Authors: Rosely S. Malafronte, Jorge Luis Valdívia, Clóvis R. Nakaie, Judith K. Kloetzel
• Format: Article in Journal/Newspaper
• Language: English
• Published: Universidade de São Paulo (USP) 1994
• Subjects: RESA/Pf155; P. falciparum; Seasonal variation; Arctic medicine. Tropical medicine; RC955-962; Infectious and parasitic diseases; RC109-216; Alta; Arctic; Paraíso
• Online Access: https://doi.org/10.1590/S0036-46651994000300008; https://doaj.org/article/c9ef41e3b363460a94666113e7fd468b

Anti-RESA/Pf155 antibodies were assayed in sera of individuals from three localities (Laranjal do Jari, Vila Padaria and Vila Paraíso) in the State of Amapá, Brazil, during the long-rains and short-rains seasons. All of these had negative blood smears for malaria. Most of the sera collected were positive in Indirect Fluorescent Antibody (IFA) with P. falciparum parasites, with no seasonal variation. A high percentage of these sera (62% to 100%) was RESA positive by Modified Indirect Fluorescent Antibody (MIFA), with a significant (p < 0.05) increase of geometric mean titers during the short-rains season, when the transmission of the disease is highest. ELISA with three repetitive RESA peptides (EENV)3 (4x3), (EENVEHDA)2 (8x2) and (DDEHVEEPTVA)2(11x2) did not reveal statistically significant seasonal variations, although a small enhancement of positivity was observed in V. Padaria (15.3 to 38.8%) in the short-rains season with the 8x2 peptides, and with 4x3 and 8x2 peptides in V. Paraíso, with a decrease in 11x2. MIFA titers appeared to be correlated mainly to the peptide 4x3 and it was the immunodominant in the three localities. Anticorpos anti-RESA/Pf155 foram testados em soros de indivíduos de três localidades (Laranjal do Jari, Vila Padaria e Vila Paraíso) localizadas no Estado do Amapá, Brasil, durante as estações de chuvas "longas" e "curtas". Todos os esfregaços apresentaram-se negativos para malária. A maioria dos soros coletados foram positivos na reação de Imunofluorescência Indireta (IFI) para P. falciparum, não apresentando variação sazonal. Uma alta porcentagem destes soros (62% a 100%) foram positivos para RESA na reação de Imunofluorescência Indireta Modificada (IFIM), com aumento na média geométrica dos títulos significante (p < 0.05) durante a estação das chuvas "curtas", época de maior transmissão da doença. O teste de ELISA com os três peptídeos repetitivos do RESA: (EENV)3(4x3), (EENVEHDA)2 (8x2) e (DDEHVEEPTVA)2(11x2), não revelou variações sazonais estatisticamente significantes, ...