Immunoepidemiology ofWuchereria bancroftiInfection: Parasite Transmission Intensity, Filaria-Specific Antibodies, and Host Immunity in Two East African Communities

Abstract

We compared the age profiles of infection and specific antibody intensities in two communities with different transmission levels in East Africa to examine the contribution of humoral responses to human immunity to the vector-borne helminth Wuchereria bancrofti. The worm intensities were higher and exhibited a nonlinear age pattern in a high-transmission community, Masaika, in contrast to the low but linearly increasing age infection profile observed for a low-transmission community, Kingwede. The mean levels of specific immunoglobulin G1 (IgG1), IgG2, IgG4, and IgE were also higher in Masaika, but intriguingly, the IgG3 response was higher in Kingwede. The age-antibody patterns differed in the two communities but in a manner apparently contrary to a role in acquired immunity when the data were assessed using simple correlation methods. By contrast, multivariate analyses showed that the antibody response to infection may be classified into three types and that two of these types, a IgG3-type response and a response measuring a trade-off in host production of IgG4 and IgG3 versus production of IgG1, IgG2, and IgE, had a negative effect on Wuchereria circulating antigen levels in a manner that supported a role for these responses in the generation of acquired immunity to infection. Mathematical modeling supported the conclusions drawn from empirical data analyses that variations in both transmission and worm intensity can explain community differences in the age profiles and impacts of these antibody response types. This study showed that parasite-specific antibody responses may be associated with the generation of acquired immunity to human filarial infection but in a form which is dependent on worm transmission intensity and interactions between immune components.

Geographic and ecologic heterogeneity in elimination thresholds for the major vector-borne helminthic disease, lymphatic filariasis

“…Although differences in the transmission dynamics of this parasitic disease have been investigated before, they have primarily focused on uncovering the impact of a priori proposed drivers of such differences, such as community vector biting rates and acquired immunity [20,21,23,24]. However, this study is the first to use empirical data to disclose the key transmission parameters that underlie observed site-specific differences in filarial transmission dynamics and the resulting endpoints for terminating parasite transmission.…”

“…The major result of this study of immediate import to LF elimination is our finding of the occurrence of significant differences in the population dynamics and the resulting transmission breakpoint estimates between the nine endemic villages investigated. Although differences in the transmission dynamics of this parasitic disease have been investigated before, they have primarily focused on uncovering the impact of a priori proposed drivers of such differences, such as community vector biting rates and acquired immunity [ 20 , 21 , 23 , 24 ]. However, this study is the first to use empirical data to disclose the key transmission parameters that underlie observed site-specific differences in filarial transmission dynamics and the resulting endpoints for terminating parasite transmission.…”

Seroepidemiology of helminths and the association with severe malaria among infants and young children in Tanzania

“…bancrofti than with O . volvulus infection [ 48 – 51 ] as does the geospatial data. Although we now have filarial species-specific recombinants for W .…”

Parasitic nematodes in humans : exploring the host-parasite dynamic through historical, biological, and public health evaluations of infection.

“…Individual acquired immunity may not be long-lasting, however (208). Another study has indicated that acquired immunity may only be attained in populations where transmission is moderate to high (209). Infection intensity has been shown to be different in areas of low transmission as compared to those of high transmission (209).…”

“…Infection intensity has been shown to be different in areas of low transmission as compared to those of high transmission (209). In areas with high transmission, infection intensity decreases with age while in low transmission areas, infection intensity increases with age (209).…”