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Lymphatic Filariasis Elimination Status: Wuchereria bancrofti Infections in Human Populations After Five Effective Rounds of Mass Drug Administration in Zambia
Matapo, B.B.; Mpabalwani, E.M.; Kaonga, P.; Simuunza, M.C.; Bakyaita, N.; Masaninga, F.; Siyumbwa, N.; Siziya, S.; Shamilimo, F.; Muzongwe, C.; Mwase, E.T.; Sikasunge, C.S. Lymphatic Filariasis Elimination Status: Wuchereria bancrofti Infections in Human Populations after Five Effective Rounds of Mass Drug Administration in Zambia. Trop. Med. Infect. Dis.2023, 8, 333.
Matapo, B.B.; Mpabalwani, E.M.; Kaonga, P.; Simuunza, M.C.; Bakyaita, N.; Masaninga, F.; Siyumbwa, N.; Siziya, S.; Shamilimo, F.; Muzongwe, C.; Mwase, E.T.; Sikasunge, C.S. Lymphatic Filariasis Elimination Status: Wuchereria bancrofti Infections in Human Populations after Five Effective Rounds of Mass Drug Administration in Zambia. Trop. Med. Infect. Dis. 2023, 8, 333.
Matapo, B.B.; Mpabalwani, E.M.; Kaonga, P.; Simuunza, M.C.; Bakyaita, N.; Masaninga, F.; Siyumbwa, N.; Siziya, S.; Shamilimo, F.; Muzongwe, C.; Mwase, E.T.; Sikasunge, C.S. Lymphatic Filariasis Elimination Status: Wuchereria bancrofti Infections in Human Populations after Five Effective Rounds of Mass Drug Administration in Zambia. Trop. Med. Infect. Dis.2023, 8, 333.
Matapo, B.B.; Mpabalwani, E.M.; Kaonga, P.; Simuunza, M.C.; Bakyaita, N.; Masaninga, F.; Siyumbwa, N.; Siziya, S.; Shamilimo, F.; Muzongwe, C.; Mwase, E.T.; Sikasunge, C.S. Lymphatic Filariasis Elimination Status: Wuchereria bancrofti Infections in Human Populations after Five Effective Rounds of Mass Drug Administration in Zambia. Trop. Med. Infect. Dis. 2023, 8, 333.
Abstract
Lymphatic filariasis (LF), also commonly known as elephantiasis, is a neglected tropical disease (NTD) caused by filarial parasites. The disease is transmitted by a bite from infected mosquitoes. The bites of these infected mosquitoes deposit filarial parasites, Wuchereria or Brugia whose predilection site is the lymphatic system. The damage to the lymph system causes swelling in the legs, arms, and genitalia. A mapping survey conducted between 2003 and 2010 determined LF that LF was endemic in Zambia in 96 out of 116 districts. Elimination of LF is known to be possible by stopping the spread of the infection through large-scale preventive chemotherapy. Therefore, mass drug administration (MDA) with diethylcarbamazine citrate (DEC) (6 mg/kg) and Albendazole (400 mg) for Zambia has been conducted and implemented in all endemic districts with five effective rounds. Post-MDA pre-transmission assessment survey (pre-TAS) was conducted between 2021 and 2022 in 80 districts to determine the LF prevalence rate. We conducted a cross-sectional seroprevalence study involving 600 participants in each Evaluation Unit (EU) or each district. The study sites (sentinel and spot-check sites) were the districts that were the Implementation Unites (IUs) where MDA, preventive chemotherapy against LF was conducted. These included 80 districts from the 9 provinces. A total of 47,235 people from sentinel and spot-check locations were tested. Of these, valid tests were 47,052 of which 27,762 (59%) were females and 19,290 (41%) were males. The survey revealed in the 79/80 endemic district a prevalence of Wb anti-gens of 0.14% and 0.0% prevalence of microfilariae. All the surveyed districts had an optimum prevalence of less than 2 percent, except for Chibombo district. The majority of participants that tested positive for Wb Ag were those that had 2, 3, and 4 rounds of MDA. Surprisingly, individuals that had 1 round of MDA were not found to have circulating antigens of Wb. The study showed that all the surveyed districts except for Chibombo, passed Pre-TAS. This further implies that there is a need to conduct a TAS in these districts in order to decide whether to stop MDA or not.
Keywords: Lymphatic Filariasis; pre-TAS; Prevalence; Antigenaemia; Microfilariae; Zambia
Public Health and Healthcare, Public Health and Health Services
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