Bancroftian filariasis in two urban areas of Recife, Brasil: the role of individual risk factors

Abstract

Bancroftian filariasis is spreading in towns of endemic areas as in Recife, northeastern Brazil, where it is a major public health problem. This paper deals with the prevalence of microfilaraemia and filarial disease in two urban areas of Recife, studying their association with individual characteristics and variables related to the exposure to the vectors. The parasitologic survey was performed through a "door-to-door" census and microfilaraemia was examined by the thick-drop technique using 45µl of peripheral blood collected between 20:00 and 24:00 o' clock. 2,863 individuals aged between 5 and 65 years were interviewed and submitted to clinical examination. Males aged between 15 and 44 years old presented the greatest risk of being microfilaraemic. Microfilaraemia was also significantly associated with no use of bednet to sleep. The risk of being microfilaraemic was greater among those who had lived in the studied areas for more than 5 years. The overall disease prevalence was 6.3%. Males presented the greatest risk of developing acute disease. The risk of developing chronic manifestations was also greater among males and increased with age. We found no association between time of residence, bednet use, microfilaraemia and acute and chronic disease. We may conclude that in endemic areas there are subgroups of individuals who has a higher risk of being microfilariae carriers due to different behaviours in relation to vector contact.

Bancroftian filariasis in an endemic area of Brazil: differences between genders during puberty

“…Nevertheless, the analysis of the association between sex and filarial infection during puberty suggests that, at least for microfilaraemia, the association between these variables occurred independently of the use of bednets and the presence of a microfilaraemic adult in the household. This result is in accordance with a previous epidemiological study carried out in a neighboring city, Recife, in which the filarial infection risk remained twice as high in men, even after adjusting for other exposure variables 1 . Therefore, despite the difficulties of measuring human exposure to infection and in controlling for all the relevant behavioral factors 7 , the data suggest that individual protection may not play a decisive role in the gender differences in lymphatic filariasis.…”

Urban lymphatic filariasis

“…quinquefasciatus and the parasite was W . bancrofti City (country)Location (number of urban sites examined)Human mf prevalence in blood smears, range (mean)Annual vector biting rate a Vector infectivity rate b Annual transmission potential c Key referencesJakarta (Indonesia)Rawasari District (2)7.8–16.3 %−0.1–0.3 %−Joe et al 1958, 1960; Chow et al 1959Kepu District (1)4.5–8.8 %223,0000.3–0.4 %1,941Oemijati et al 1975; Mahfudin et al 1977; Self et al 1978Rangoon (Burma)Kemmendine4.9 %83,0000.36 %1,357De Meillon et al 1967; Hairston and De Meillon 1968Calcutta (India)Howrah suburb (1)12.4–14.8 %115,0001.5 %5,904Bhattacharya and Gubler 1973; Gubler and Bhattacharya 1974; Dondero et al 1976Central Calcutta (1)2.5 %55,0000.3 %319Hati et al 1989Pondicherry (India)Pondicherry City (14)10.2–30.0 % (17.8 %)88,5001.25 %5,178Rajagopalan et al 1977Pondicherry City (1)8.4 %26,2000.86 %450Rajagopalan et al 1987, 1989; Ramaiah et al 1992Chennai (India)Chennai City (7)1.1–7.3 %−−−Hyma et al 1989Chennai City0.0–4.5 %−−−Ramaiah et al 2005; Kumar and Ramaiah 2008Greater Recife (Brazil)Recife City (2)9.3–10.7 %−−−Albuquerque et al 1995a and b; Braga et al 1998Recife and Olinda cities (2)12.3–13.5 %−−...…”

“…A survey among 4,600 individuals (5–65 years) in two slum areas during 1990–1991 showed mf prevalence rates of 9.3 and 10.7 % (Albuquerque et al 1995a, b; Braga et al 1998). The overall LF disease prevalence was 6.3 % (mainly hydrocele and lymphoedema).…”

“…quinquefasciatus . Lack of sewerage system (Neto 1993; Rajagopalan et al 1977; Albuquerque et al 1995a, b; Maciel et al 1996; Fontes et al 1998) and poorly maintained (damaged and/or clogged) open drainage systems (Oemijati et al 1975; Mahfudin et al 1977; Self et al 1978; Williams 1968; Abdulcader 1971; Rozeboom et al 1968; Rajagopalan et al 1977; Albuquerque et al 1995b) were some of the most commonly reported causes for creation of highly productive vector breeding sites. Others were waste water pools near houses and wells (Chow et al 1959; Joe et al 1960; Gubler and Bhattacharya 1974; Rajagopalan et al 1977), urban swamps and ponds (Williams 1968; Rajagopalan et al 1977, 1987), urban agriculture (Joe et al 1958), wet pit latrines (Williams 1968; Maxwell et al 1999) and even flooded basements (Maxwell et al 1999).…”

Screening of army soldiers for Wuchereria bancrofti infection in the metropolitan Recife region, Brazil: implications for epidemiological surveillance

“…In most populations where lymphatic filariasis is endemic, the prevalence of microfilaraemia tends to increase with age to about 20 years, after which it remains consistently high (Brabin 1990;Lammie et al 1994;Albuquerque et al 1995;Chanteau et al 1995). In addition, during the reproductive years, the prevalence of microfilaraemia tends to be higher in males than in females (Brabin 1990;Pani et al 1991;Albuquerque et al 1995). The prevalence of chronic filarial disease, such as hydrocele, tends to increase with age; thus most infected young males are asymptomatic (Ottesen 1993;Norões et al 1996).…”