Epidemiological Study of Bancroftian Filariasis in Recife, Northeastern Brazil
Amélia Maciel, Abraham Rocha, Keyla Belizia F Marzochi*, Zulma Medeiros, Alexandre B Carvalho, Leda Regis, Wayner Souza, Tiago Lapa, André Furtado/+
Vol. 91(4): 449-455, Jul./Aug. 1996
Centro de Pesquisas Aggeu Magalhães-FIOCRUZ, Caixa Postal 7472, Campus UFPE, 50670-420 Recife, PE, Brasil *Escola Nacional de Saúde Pública, Fundação Oswaldo Cruz, R. Leopoldo Bulhões 1480, 21041-210, Rio de Janeiro, RJ, Brasil
Wuchereria bancrofti in Pernambuco was first documented in 1952 (Azevedo & Dobbin 1952), and since then it has been reported in surveys carried out in selected areas of Recife. Several surveys were carried out from 1981 to 1991 by SUCAM. In the 1985 SUCAM's report the disease is considered under control. The CPqAM Filariasis Research Program was established in 1985 and a filarial survey was carried out in the town of Olinda, Greater Recife. In order to verify the real epidemiological situation, a study was conducted in the city of Recife.
21/36 of the Special Zones of Social Interest (ZEIS), were randomly selected for the present study. From 10,664 persons screened, 683 were positive and the prevalence rate for microfilaraemia (mf) varied from 0.6% to 14.9%. A mean mf prevalence of 6.5%, showed that the infection occurs in a wide geographic distribution in Greater Recife and that the intensity of transmission is a real and potential threat to public health in affected communities. Mf rate among males and females differed significantly. Due to the rapid increase in population, unplanned urban settlements, poor sanitary facilities and the favorable geographical conditions to the development of the vector, filariasis may actually be increasing in Recife.
Key words: filariasis - Wuchereria bancrofti - Culex quinquefasciatus - epidemiology - sex distribution - age distribution
Lymphatic filariasis is an endemic infection associated with three parasites - Wuchereria bancrofti, Brugia malayi and Brugia timori.The World Health Organization (WHO) estimated 72.8 million persons infected with W. bancrofti, and 5.8 millions with B. malayi and B. timori, among a total of 751 millions exposed (WHO 1992).
The presence of W. bancrofti in Brazil was first reported in 1877 (Pessoa 1978) and there is a presupposition that the disease was brought by the African slaves. The city of Salvador, State of Bahia, was the first historic focus of this infection (Parahym 1961).
In Recife, northeast of Brazil, the disease was first documented in 1952, when the prevalence rate recorded was 9.7% (Azevedo & Dobbin 1952).
In 1954, a large country-wide filarial survey was carried out. High levels of endemicity were found only in the cities of Recife and Belém (north of Brazil), with an estimate that a total of 50,000 to 80,000 persons were infected in both areas (Rachou & Deane 1954).
A National Program for the Control of Lymphatic Filariasis was created by the National Department of Rural Endemics (DNERu). In 1970 this Department took the name of SUCAM (Health Campaigns Superintendency), at present FNS (National Health Foundation). From 1954 to 1981, there have been eleven filarial surveys in Recife. The crude microfilaraemia rate found during this period ranged between 6.9% and 2.3%. Finally, in a survey completed in 1983, including active and passive search, 246,818 persons were examined from which 2,477 (1%) were found positive, indicating that the disease had reached a very low level of endemicity. A detailed epidemiological report, based on data from SUCAM, concluded that the endemy was under control (Ministério da Saúde 1985).
In May 1986, the CPqAM Filariasis Research Program was established. A filarial survey in Sapucaia, district of Olinda, Greater Recife, utilizing a different method of blood collection and the technique of nuclepore filtration, instead of blood smears, showed values of microfilarial prevalence up to 40% (Dreyer & Medeiros 1990).With the aim of providing both more precise estimates of prevalence in the communities surveyed and its distribution by gender and major age-group categories overall, in order to offer alternatives for future control programs, a filarial survey covering Recife and Greater Recife was carried out during 1991-1992.
ACKNOWLEDGMENTS
To the National Health Foundation, Pernambuco State Health Secretary and Recife Health Secretary.
Fig. 1 | Fig. 2 | Fig. 3 | Fig.4 | Fig. 5
Table I | Table II | Table III
This work was supported by UNPD/World Bank/WHO/ Special Program for Research and Training in Tropical Diseases (TDR), Conselho Nacional de Desenvolvi-mento Científico e Tecnológico (CNPq) and Fundação de Amparo à Ciência e Tecnologia do Estado de Pernambuco FACEPE.
+Corresponding author. Fax:Received 11 October 1995
Accepted 12 February 1996
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