Home » Volumes » Volume 21 January/March 1988 » Infrequency of asymptomatic malaria in an endemic area in Amazonas, Brazil

Infrequency of asymptomatic malaria in an endemic area in Amazonas, Brazil

Aluizio Prata; Margarita Urdaneta; Patrick B. McGreevy; Mauro Shugiro Tada

DOI: 10.1590/S0037-86821988000200003


ABSTRACT

A malaria survey was conducted in an area of high transmission (Costa Marques, Rondonia, Brazil) to determine the prevalence of asymptomatic parasitemia and its clinical significance. Most of the people surveyed were immigrants who had lived in the endemic area < 5 years. The people had easy access to free diagnostic and treatment services at the Malaria Clinic in the town of Costa Marques. The prevalence of plasmodial parasitemia in 344 people was 22%. There were 36 individuals with asymptomatic infections among the 77 parasitemic patients. During the two days following the initial examination, 19 ofthe 36 individuals: with asymptomatic infections developed malaria. Among the 17 patients who remained asymptomatic for > 2 days, 4 had only gametocytes, 1 had taken inadequate anti-malarial treatment, 3 were under treatment and 2 moved. Six asymptomatic patients denied the use of anti-malarial drugs and they developed malaria 3-6 days after the initial parasitological diagnosis. The final patient remained asymptomatic during the 7 day observation period. He had a history of > 40 malaria attacks and denied the use of antimalarial treatment. With the exception of the latter all of the other asymptomatic patients, were either in the incubation period or had been treated It is concluded that asymptomatic malaria is rare in the Costa Marques area and that it is necessary to treat all individuals with plasmodial parasitemia.

Keywords: Malaria. Asymptomatic malaria. Plasmodium falciparum. Plasmodium vivax. Brazil.


RESUMO

Em uma área de alta transmissão de malária (Costa Marques, Rondônia) foi feito um estudo para determinar a prevalência de parasitemia assintomática e seu significado clínico. A maioria dos habitantes estudados era imigrante que vivia na região há menos de 5 anos. Em Costa Marques há facilidades para o diagnóstico e pronto tratamento da malária. Em 344 pessoas examinadas havia 77 (22%) com parasitemia para hematozoários. Entre estes, 36 não tinham sintomatologia de malária. Após dois dias, 19 dos 36 desenvolveram sintomatologia. Dos 17 que continuavam assintomáticos, 4 tinham somente gametócitos no esfregaço de sangue examinado, 1 tinha recebido tratamento antimalárico inadequado, 3 estavam em tratamento e 2 se mudaram da área. Entre o 3.o e 6.o dia 6 apresentaram sintomatologia. Um paciente continuou assintomático no 7.o dia, quando terminou a observação. Ele contava já ter tido mais de 40 ataques de malária. Exceto ele, todos os outros assintomáticos ou estavam no período de incubação ou em tratamento. Conclui-se que a malária assintomática é rara em Costa Marques e que é necessário tratar todos os indivíduos com parasitemia.

Palavras-chave: Malária. Malária assintomática. Plasmodium falciparum. Plasmodium vivax. Brasil.


 

 

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REFERENCES

1. Bruce-Chwatt LJ. A longitudinal survey of natural malaria infection in a group of West African adults. Part I and II. West African Medical Journal 12:1-52,1963.         [ Links ]

2. Chagas C, Chagas E. Manual de Doenças Tropicais e Infectuosas. Volume I. Livraria Editora Freitas Bastos. Rio de Janeiro, 1935.         [ Links ]

3. Cobran KMcL. Malaria in the partially immune adult Nigerian. The Journal of Tropical Medicine and Hygiene 60:233-237, 1960.         [ Links ]

4. Gamham PCC, Wilson DB, Swellengrebel NH. A review of hyperendemic malaria. Tropical Disease Bulletin. 47:677-698, 1950.         [ Links ]

5. Greenwood BM. Asymptomatic malaria infections – Do they matter?. Parasitology Today 3:206-214,1987.         [ Links ]

6. McGregor IA. The significance of parasitic infections in terms of clinical diseases: A personal view. P arasitology 94(Suppl.): 159-178, 1987.         [ Links ]

7. Organización Mundial de la Salud. Quimioterapia del Paludismo. Séries Monográficas. 27. Ginebra, 1982.         [ Links ]

8. Schwetz J, Peel M. Congenital malaria and placental infections amongst negroes of Central Africa. Transactions of the Royal Society of Tropical Medicine and Hygiene. 28:167-174, 1934.         [ Links ]

9. World Health Organization. Advances in Malaria Chemotherapy. Technical Report Series 711. Geneva, 1984.         [ Links ]

 

 

 Adress to correspondence:
Núcleo de Medicina Tropical e Nutrição
Universidade de Brasília
70.910
Brasília, DF, Brazil.

 

 

Recebido para publicação em 4/6/88.

 

 

This study was supported under a collaborative agreement between the University of Brasilia and the Walter Reed Army Institute of Research, grant number DAMD17-84-G-4007.