< i > Onchocerca volvulus < /i > -specific antibody and cellular responses in onchocerciasis patients treated annually with ivermectin for 30 years and exposed to parasite transmission in central Togo

Conclusions/SignificanceRepeated annual ivermectin treatment of onchocerciasis patients durably inhibited their patentO.volvulus infections despite ongoing low-level parasite transmission in the study area. Repeated MDA with ivermectin affects the expression of immunity in patients.O.volvulus parasite-specific antibody levels diminished to levels seen in infection-free endemic controls. With low antibody levels, antibody-dependent cellular cytotoxic responses against tissue-dwellingO.volvulus larvae will weaken.O.volvulus antigen inducible cytokine and chemokine production increased in treated mf-negative patients, while their innate responsiveness to mitogen declined. Such lower innate responsiveness in elderly patients could contribute to reduced adaptive immune responses to parasite infections and vaccines. On the other hand, increased specific cellular chemokine responses in mf-negative onchocerciasis patients could reflect effector cell activation against tissue invasive larval stages ofO.volvulus. The annualSimulium damnosum s.l. biting rate observed in the M รด river basin was similar to levels prior to initiation of MDA with ivermectin, and the positive rtPCR results reported here confirm ongoingO.volvulus transmission.
Source: PLoS Neglected Tropical Diseases - Category: Tropical Medicine Authors: Source Type: research