Onchocerciasis Elimination Mapping in Tanzania Mainland: A case of Iringa DC, Kilolo DC, Handeni DC and Kilindi DC,

Abstract Background In Tanzania, seven councils were showed possibility of endemicity of Onchocerciasis. For this reason, a desktop review of Onchocerciasis exclusion mapping was undertaken in these councils with reference to the vectors and categorized the district ecology as suitable or unsuitable for vector breeding. Out of seven councils, four councils were met the suitable criteria for conducting Onchocerciasis elimination mapping (OEM). The OEM aimed to determine the level of exposure to onchocerciasis among children 5 to 9 years age in four councils. Methods A community-based cross-sectional survey was conducted between May and July 2023 using multistage sampling of 30 villages. Mapping was conducted in four councils that were merged to form two Evaluation units (EUs) of Kilindi-Handeni close to Tanga focus located northeast and Kilolo and Iringa close to Mahenge in the southwest of Tanzania. The target population were 6,000 children of 5 to 9 years that have been living in the selected villages for their entire lives. Results A total of 6,054 children were sampled from the two EUs whereby 3,044 children came from Handeni-Kilindi EU and 3,010 came from Kilolo-Iringa DC EU. A total of 5 (0.1%) out of 6,054 tested children were seropositive for IgG4 antibodies using OV-16 RDT from the two EUs, whereby 2 (0.07%) came for Handeni-Kilindi and 3 (0.1%) came from Kilolo-Iringa. Conclusions Based on these study findings, there is no transmission of onchocerciasis currently taking place in the assessed EUs. It is vital that appropriate surveillance procedures are now implemented to confirm and ensure that no transmission remains. Keywords Onchocerciasis, Elimination Mapping, Mass Drug Administration, Exclusion Mapping ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement This Study was funded by USAID through Act to End Neglected Tropical Disease program implemented in Tanzania ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: Approval for the study was provided by the Institutional Review board of the Ministry of Health in Tanzania through NTDCP and Research Triangle Institute in Washington DC I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes All data produced in the present work are contained in the manuscript