|Background: Lymphatic filariasis (LF) control started in Tanga Region of Tanzania in 2004, with annual ivermectin/
albendazole mass drug administration (MDA). Since then, the current project has monitored the effect in
communities and schools in rural areas of Tanga District. In 2013, after 8 rounds of MDA, spot check surveys were
added in the other 7 districts of Tanga Region, to assess the regional LF status.
Methods: LF vector and transmission surveillance, and human cross sectional surveys in communities and schools,
continued in Tanga District as previously reported. In each of the other 7 districts, 2–3 spot check sites were
selected and about 200 schoolchildren were examined for circulating filarial antigens (CFA). At 1–2 of the sites in
each district, additional about 200 community volunteers were examined for CFA and chronic LF disease, and the
CFA positives were re-examined for microfilariae (mf).
Results: The downward trend in LF transmission and human infection previously reported for Tanga District
continued, with prevalences after MDA 8 reaching 15.5% and 3.5% for CFA and mf in communities (decrease by
75.5% and 89.6% from baseline) and 2.3% for CFA in schoolchildren (decrease by 90.9% from baseline). Surprisingly,
the prevalence of chronic LF morbidity after MDA 8 was less than half of baseline records. No infective vector
mosquitoes were detected after MDA 7. Spot checks in the other districts after MDA 8 showed relatively high LF
burdens in the coastal districts. LF burdens gradually decreased when moving to districts further inland and with
Conclusion: LF was still widespread in many parts of Tanga Region after MDA 8, in particular in the coastal areas.
This calls for intensified control, which should include increased MDA treatment coverage, strengthening of bed net
usage, and more male focus in LF health information dissemination. The low LF burdens observed in some inland
districts suggest that MDA in these could be stepped down to provide more resources for upscale of control in the
coastal areas. Monitoring should continue to guide the programme to ensure that the current major achievements
will ultimately lead to successful LF elimination.|