Decade of mass drug administration reduces Lymphatic filariasis and parasite density in Billiri and Kaltungo districts of Gombe State, Nigeria

Abstract

Background: Lymphatic filariasis is a neglected tropical disease caused by mosquito-borne nematodes: Wuchereria bancrofti, Brugia timori, and Brugia malayi, and it affects over 120 million people worldwide. The Global Program for Elimination of Lymphatic Filariasis, in 2000, initiated the mass drug administration (MDA) to interrupt parasite transmission in endemic areas. This study employed anti-filarial antibodies (AFA), circulating microfilariae, and pWb12 DNA repeats to assess the impact of ten years MDA and prevalence of W. bancrofti in Billiri and Kaltungo LGAs of Gombe State, Nigeria. Methodology: All MDA data were collected from the Gombe State Primary Health Care Board. A total of 394 individuals from Billri and Kaltungo districts were selected for anti-filarial antibody tests from 10 districts between April-August 2022. Blood was collected between 10 pm- 2 am and screened for microfilariae at 100X magnifications using Knott’s microscopy test. Mosquitoes were also collected using CDC light traps and subjected to DNA extraction along with collected blood samples. Nested polymerase chain reaction (PCR) was performed to amplify pWb12 DNA repeats and amplicons were electrophoresed on 1.5% agarose gel. Findings: The data showed 60-88% ten years MDA coverage in 194 communities studied. Prevalence by AFA was 1.8% (7/394) immunoglobulin G (IgG) but negative for IgM. Microscopy by Knott’s test detected no microfilariae in all blood samples and Nested-PCR showed no amplified pWb12 DNA repeats. Overall, AFA data revealed that the areas were previously infected as evidenced by 1.8% IgG positives, but there were no active infections, as all individual blood samples were amicrofilaremic by microscopic examination, further confirmed by negative PCR results. Conclusions: Therefore, this study suggests high effectiveness of the ten years MDA of Albendazole against lymphatic filariasis. It also reports the absence of the disease, with antigenemia and fileremia prevalence less than 1% threshold required for the cessation of MDA, and has provided valuable information on the status of Lymphatic filariasis in Billiri and Kaltungo districts of Gombe State, Nigeria.