Impact of malaria mass-test treat exercise on antipfeba- 175 antibody levels in a malaria endemic community

Abstract

One key factor influencing the manifestation of malaria is naturally acquired immunity (NAI) against the parasite, which is developed after repeated exposure by people living in endemic areas. Efforts to further decrease the incidence of malaria have resulted in the implementation of a wide variety of malaria control and elimination measures, each with the potential to alter the development of NAI. We monitored total IgG against PfEBA-175 antigen quarterly over a 13-month period in individuals living in a high malaria transmission setting (Obom) where a mass test, treat and track (MTTT) exercise was rolled out. 1200 individuals without any symptoms of malaria aged between 7 months and 90 years were enrolled on the study and donated finger-pricked blood that was used to prepare dried blood spots (DBS). Out of this number, 314 individuals who were present for all four sampling time points were selected for the study. Genomic DNA was extracted from the DBS from these individuals for PCR estimate of P. falciparum. Antibodies were also eluted from the DBS and used for PfEBA-175-specific ELISA. The results were stratified by age into 0-4 years, 5-9 years, 10-15 years and 16+ years groups. Across visits, there was a gradual rise in antibody levels at each time point, however, this was not statistically significant. Individuals aged 16 and above had higher antibody titres than individuals aged 15 and below. The study revealed that all the age categories had higher antibody titres with mean significant differences at the end of the period except those in the age group 10-15 years whose differences in antibody titres at the end of the study were not statistically significant. Generally, higher antibody levels were associated with those infected compared to the uninfected. This study established that MTTT intervention does not significantly reduce antibody titres against the PfEBA-175 antigen after a year of its rollout in an endemic community.