The present study was undertaken in village Karondang in South-Sulawesi, Indonesia, to investigate the influences of
genetic, household and environmental factors on Brugia malayi infection. Infection status was determined by measuring
both microfilariae in night blood and anti-filarial IgG4, as a marker for detection of active filarial infection. A total of 171
residents participated in the study; familial relationships between subjects were registered to construct pedigrees and
distances between households were measured. The data were analysed using a test statistic for familial aggregation. For
distribution of microfilariae over the study population a genetic influence on infection susceptibility was favoured over the
household and environmental effects. For anti-filarial IgG4, all 3 clustering models gave significant results, suggesting that
genetic, household and/or environmental factors influence specific IgG4 antibodies.