{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"institution":[{"name":"medRxiv"}],"indexed":{"date-parts":[[2026,1,16]],"date-time":"2026-01-16T14:06:24Z","timestamp":1768572384609,"version":"3.49.0"},"posted":{"date-parts":[[2025,8,19]]},"group-title":"Epidemiology","reference-count":57,"publisher":"openRxiv","license":[{"start":{"date-parts":[[2025,8,19]],"date-time":"2025-08-19T00:00:00Z","timestamp":1755561600000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"accepted":{"date-parts":[[2025,8,19]]},"abstract":"<jats:title>ABSTRACT<\/jats:title>\n                <jats:p>\n                  Current interventions targeting malaria control in sub-Saharan Africa (SSA) are focused on\n                  <jats:italic>Plasmodium falciparum<\/jats:italic>\n                  , the most prevalent species infecting humans. Despite renewed efforts for malaria elimination in SSA, little attention has been paid to the neglected parasites\n                  <jats:italic>P. malariae<\/jats:italic>\n                  and\n                  <jats:italic>P. ovale<\/jats:italic>\n                  spp. and the impact of interventions like long-lasting insecticidal nets (LLINs), indoor residual spraying (IRS) with non-pyrethroid insecticides, and\/or seasonal malaria chemoprevention (SMC) on these minor\n                  <jats:italic>Plasmodium<\/jats:italic>\n                  spp. To address this research gap, this study was undertaken to assess the efficacy of two sequential interventions, IRS and SMC combined with LLINs, on minor-\n                  <jats:italic>Plasmodium<\/jats:italic>\n                  spp. infections in Bongo District, an area characterized by high seasonal transmission in the Northern Sahelian belt of Ghana. Using an interrupted time-series study, five age-stratified surveys, each of \u223c2,000 participants, were undertaken at the end of the wet seasons between 2012 and 2022. Across this 10-year study period, infections with\n                  <jats:italic>P. malariae<\/jats:italic>\n                  and\n                  <jats:italic>P. ovale<\/jats:italic>\n                  spp. were detected using a species-specific PCR targeting the\n                  <jats:italic>18S rRNA<\/jats:italic>\n                  gene. In 2015, following IRS, the prevalence of the minor\n                  <jats:italic>Plasmodium<\/jats:italic>\n                  spp. declined in all ages from baseline in 2012, with participants being significantly less likely to be infected with\n                  <jats:italic>P. malariae<\/jats:italic>\n                  (13.7% vs 1.4%) and\n                  <jats:italic>P. ovale<\/jats:italic>\n                  spp. (5.7% vs 0.4%). Despite this decline, in 2017, 32 months after IRS was discontinued and SMC was introduced, the prevalence of\n                  <jats:italic>P. malariae<\/jats:italic>\n                  (2.9%) and\n                  <jats:italic>P. ovale<\/jats:italic>\n                  spp. (4.0%) rebounded 2- and 10-fold, respectively. This rebound in the minor species was observed in all age groups, except for the younger children (&lt; 5 years) targeted by SMC. Finally, when we examined this population in 2020 and 2022 after sustained deployment of SMC, the prevalence of\n                  <jats:italic>P. malariae<\/jats:italic>\n                  continued to increase (7.4% and 5.8%), while the prevalence of\n                  <jats:italic>P. ovale<\/jats:italic>\n                  spp. declined (2.6% and 1.3%). Results show that both IRS and SMC were effective not only against\n                  <jats:italic>P. falciparum<\/jats:italic>\n                  but also reduced the prevalence of\n                  <jats:italic>P. malariae<\/jats:italic>\n                  and\n                  <jats:italic>P. ovale<\/jats:italic>\n                  spp. in Bongo District. Going forward, molecular diagnostics will be critical to identify changes in the submicroscopic reservoir of the minor\n                  <jats:italic>Plasmodium<\/jats:italic>\n                  spp. found in adolescents and adults and to achieve malaria elimination in this region of Ghana.\n                <\/jats:p>\n                <jats:sec>\n                  <jats:title>AUTHOR SUMMARY<\/jats:title>\n                  <jats:p>\n                    To achieve malaria elimination, the use of molecular diagnostics for surveillance of the\n                    <jats:italic>Plasmodium<\/jats:italic>\n                    spp. reservoir is essential. Such diagnostics are critical to detect hidden reservoirs of submicroscopic minor-species infections with\n                    <jats:italic>P. malariae<\/jats:italic>\n                    and\n                    <jats:italic>P. ovale<\/jats:italic>\n                    spp. Here we examine the impact of two sequential malaria control interventions, indoor residual spraying (IRS) with non-pyrethroid insecticides and seasonal malaria chemoprevention (SMC) with sulfadoxine-pyrimethamine plus amodiaquine administered to all children &lt; 5 years, combined with long-lasting insecticidal nets (LLINs) impregnated with pyrethroids to reduce the reservoir of\n                    <jats:italic>Plasmodium<\/jats:italic>\n                    spp. infections where\n                    <jats:italic>P. falciparum<\/jats:italic>\n                    is dominant and the minor species,\n                    <jats:italic>P. malariae<\/jats:italic>\n                    and\n                    <jats:italic>P. ovale<\/jats:italic>\n                    spp., were also found. This interrupted time-series study, undertaken over 10 years (2012-2022) in Bongo District, located in the Northern Sahelian belt of Ghana, identified that IRS and SMC reduced the prevalence of all\n                    <jats:italic>Plasmodium<\/jats:italic>\n                    spp. IRS significantly reduced the prevalence of single- and mixed-\n                    <jats:italic>Plasmodium<\/jats:italic>\n                    spp. infections across all age groups. However, following its discontinuation a rebound was observed for\n                    <jats:italic>P. falciparum<\/jats:italic>\n                    and minor-species infections, especially in adolescents and adults. Although SMC maintained a near-zero prevalence of all\n                    <jats:italic>Plasmodium<\/jats:italic>\n                    spp. infections, its impact was limited to the target age group (&lt; 5 years). Furthermore, this study showed that following the discontinuation of IRS, the older children, adolescents, and adults, not eligible for SMC, continued to harbour\n                    <jats:italic>Plasmodium<\/jats:italic>\n                    spp. infections, including minor species, thus sustaining the reservoir. These results show that by combining vector control inventions as well as targeting all age groups with chemoprevention, high-burden countries in sub-Saharan Africa, including Ghana, could bring the\n                    <jats:italic>Plasmodium<\/jats:italic>\n                    spp. reservoir closer to elimination more rapidly.\n                  <\/jats:p>\n                <\/jats:sec>","DOI":"10.1101\/2025.08.15.25333797","type":"posted-content","created":{"date-parts":[[2025,8,19]],"date-time":"2025-08-19T15:35:16Z","timestamp":1755617716000},"source":"Crossref","is-referenced-by-count":0,"title":["Longitudinal analysis of the prevalence of minor\n                  <i>Plasmodium<\/i>\n                  spp. in the reservoir of asymptomatic infections through sequential interventions in Northern Sahelian Ghana"],"prefix":"10.64898","author":[{"ORCID":"https:\/\/orcid.org\/0009-0007-9301-2068","authenticated-orcid":false,"given":"Cecilia A.","family":"Rios-Teran","sequence":"first","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3305-0533","authenticated-orcid":false,"given":"Kathryn E.","family":"Tiedje","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1491-1510","authenticated-orcid":false,"given":"Oscar","family":"Bangre","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Samantha L.","family":"Deed","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8068-0215","authenticated-orcid":false,"given":"Dionne C.","family":"Argyropoulos","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Kwadwo A.","family":"Koram","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4191-7419","authenticated-orcid":false,"given":"Abraham R.","family":"Oduro","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3214-5621","authenticated-orcid":false,"given":"Patrick O.","family":"Ansah","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6115-6135","authenticated-orcid":false,"given":"Karen P.","family":"Day","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"54368","reference":[{"key":"2025082110300866000_2025.08.15.25333797v1.1","doi-asserted-by":"publisher","DOI":"10.1038\/nature15386"},{"key":"2025082110300866000_2025.08.15.25333797v1.2","doi-asserted-by":"publisher","DOI":"10.1016\/j.ijpara.2021.06.003"},{"key":"2025082110300866000_2025.08.15.25333797v1.3","doi-asserted-by":"publisher","DOI":"10.1186\/s12889-019-6576-9"},{"key":"2025082110300866000_2025.08.15.25333797v1.4","doi-asserted-by":"publisher","DOI":"10.1186\/s13071-021-05118-1"},{"key":"2025082110300866000_2025.08.15.25333797v1.5","doi-asserted-by":"publisher","DOI":"10.1155\/2021\/7419548"},{"key":"2025082110300866000_2025.08.15.25333797v1.6","doi-asserted-by":"publisher","DOI":"10.1093\/infdis\/jiab353"},{"key":"2025082110300866000_2025.08.15.25333797v1.7","doi-asserted-by":"publisher","DOI":"10.1371\/journal.pntd.0006994"},{"key":"2025082110300866000_2025.08.15.25333797v1.8","doi-asserted-by":"publisher","DOI":"10.1371\/journal.pmed.1001630"},{"key":"2025082110300866000_2025.08.15.25333797v1.9","doi-asserted-by":"publisher","DOI":"10.1371\/journal.pmed.1002181"},{"key":"2025082110300866000_2025.08.15.25333797v1.10","doi-asserted-by":"publisher","DOI":"10.4269\/ajtmh.2011.10-0684"},{"key":"2025082110300866000_2025.08.15.25333797v1.11","doi-asserted-by":"crossref","first-page":"1104","DOI":"10.1093\/infdis\/jiy628","article-title":"Persistent Parasitemia Despite Dramatic Reduction in Malaria Incidence After 3 Rounds of Indoor Residual Spraying in Tororo, Uganda","volume":"219","year":"2019","journal-title":"Journal of Infectious Diseases"},{"key":"2025082110300866000_2025.08.15.25333797v1.12","doi-asserted-by":"publisher","DOI":"10.1371\/journal.pgph.0000285"},{"key":"2025082110300866000_2025.08.15.25333797v1.13","unstructured":"National Malaria Control Programme, Ghana Health Service, Ministry of Health. 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