House types and demographic risk factors for sustained endemic filariasis in south-eastern Nigeria

ABSTRACT

This study was aimed at assessing both the quality of housing in the coastal and upland areas of Eastern Nigeria using a predetermined three-category house type approach, as well as the distance of the respective houses from major vector breeding sites, in relation to the prevalence of microfilaraemia. From each community, all individuals who were more than one year old or resident in the area for at least a year were screened. The target population was 1000 persons each for coastal and upland areas. Houses in the areas were categorized into three main types. Type I mud houses built with thatched roofs, small windows and yawning eaves that hold no barrier for mosquitoes; Type II mud houses built with zinc roofing sheets; Type III modern-style houses built and plastered with cement and having large doors and windows. A total of 855 houses were screened, out of which 191 (22.3%) were Type I; while 430 (50.3%) and 234 (27.4%) were Type II and Type III respectively. An average of three and four persons per house was recorded for the Upland and Coastal populations respectively. Familial clustering was the settlement pattern in the former, while houses were adjoined one to another in the latter. In the Upland area, 10.0% of the houses had at least one Wuchereria bancrofti microfilaraemia (Wbmf) positive individual, and this comprised of 8.7% harbouring one mf positive individual each, and 1.3% housing two Wbmf positive individuals each. In total, 52% of all positive microfilaraemia cases were from Type I while 39% and 9% of positive microfilaraemia cases were from Type II and Type III respectively. Microfilaraemia was significantly higher among those that lived in poorest quality house type, and in proximity to major vector breeding sites such as streams.