Hyperendemicity of Rift Valley fever in Southwestern Uganda associated with the rapidly evolving lineage C viruses

Introduction: Recent Rift Valley fever (RVF) epidemiology in eastern Africa region is characterized by widening geographic range and increasing frequency of small disease clusters. Here we conducted studies in the southwestern (SW) Uganda region that has since 2016 reported increasing RVF activities...

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Main Authors: Bakamutumaho, B., Juma, John, Clancey, E., Nyakarahuka, L., Situma, S., Odinoh, R., Dawa, J., Nasimiyu, C., Eskew, E.A., Balinandi, S., Mulei, S., Kayiwa, J., Klena, J.D., Shoemaker, T.R., Whitmer, S.L.M., Montgomery, J.M., Schieffelin, J., Lutwama, J., Muruta, A., Bosa, H.K., Nuismer, S.L., Oyola, Samuel O., Breiman, R.F., Njenga, M.K.
Format: Journal Article
Language:Inglés
Published: Oxford University Press 2026
Subjects:
Online Access:https://hdl.handle.net/10568/175998
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author Bakamutumaho, B.
Juma, John
Clancey, E.
Nyakarahuka, L.
Situma, S.
Odinoh, R.
Dawa, J.
Nasimiyu, C.
Eskew, E.A.
Balinandi, S.
Mulei, S.
Kayiwa, J.
Klena, J.D.
Shoemaker, T.R.
Whitmer, S.L.M.
Montgomery, J.M.
Schieffelin, J.
Lutwama, J.
Muruta, A.
Bosa, H.K.
Nuismer, S.L.
Oyola, Samuel O.
Breiman, R.F.
Njenga, M.K.
author_browse Bakamutumaho, B.
Balinandi, S.
Bosa, H.K.
Breiman, R.F.
Clancey, E.
Dawa, J.
Eskew, E.A.
Juma, John
Kayiwa, J.
Klena, J.D.
Lutwama, J.
Montgomery, J.M.
Mulei, S.
Muruta, A.
Nasimiyu, C.
Njenga, M.K.
Nuismer, S.L.
Nyakarahuka, L.
Odinoh, R.
Oyola, Samuel O.
Schieffelin, J.
Shoemaker, T.R.
Situma, S.
Whitmer, S.L.M.
author_facet Bakamutumaho, B.
Juma, John
Clancey, E.
Nyakarahuka, L.
Situma, S.
Odinoh, R.
Dawa, J.
Nasimiyu, C.
Eskew, E.A.
Balinandi, S.
Mulei, S.
Kayiwa, J.
Klena, J.D.
Shoemaker, T.R.
Whitmer, S.L.M.
Montgomery, J.M.
Schieffelin, J.
Lutwama, J.
Muruta, A.
Bosa, H.K.
Nuismer, S.L.
Oyola, Samuel O.
Breiman, R.F.
Njenga, M.K.
author_sort Bakamutumaho, B.
collection Repository of Agricultural Research Outputs (CGSpace)
description Introduction: Recent Rift Valley fever (RVF) epidemiology in eastern Africa region is characterized by widening geographic range and increasing frequency of small disease clusters. Here we conducted studies in the southwestern (SW) Uganda region that has since 2016 reported increasing RVF activities. Methods: A 22-month long hospital-based study in three districts of SW Uganda targeting patients with acute febrile illness (AFI) or unexplained bleeding was followed by a cross-sectional population-based human-animal survey. We then estimated RVFV force of infection (FOI) and yearly cases using the age-structured seroprevalence data and conducted genomic phylodynamic modelling of RVFV isolates. Results: Overall RVF prevalence was 10.5% (205 of 1,968) among febrile or hemorrhagic cases, including 5% (100 of 1,968) with acute (PCR or IgM positive) infection, averaging 5 cases per month. Community-based seroprevalence of 11.8% (88/743) among humans and 14.6% (347/2,383) in livestock was observed. Expected yearly human RVF cases were 314-2,111 per 1,369 km2 in SW Uganda, up to 3-fold higher than the 0-711 yearly cases in comparable regions of Kenya and Tanzania. Viral genomic studies identified RVFV lineage C, sub-clade C.2.2, as the circulating strain in SW Uganda since 2019. Lineage C strain has undergone recent rapid evolution and clonal expansion resulting in four sub-clades, C.1.1, C.1.2, C.2.1, and C.2.2, that are adept at establishing endemicity in new territories. Conclusions: We demonstrate an atypical RVF hyperendemic region in SW Uganda characterized by sustained human clinical RVF cases, unusually high population prevalence, and high number of expected yearly human cases, associated in part with emergence of new RVFV sub-lineages.
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spelling CGSpace1759982026-01-19T08:08:47Z Hyperendemicity of Rift Valley fever in Southwestern Uganda associated with the rapidly evolving lineage C viruses Bakamutumaho, B. Juma, John Clancey, E. Nyakarahuka, L. Situma, S. Odinoh, R. Dawa, J. Nasimiyu, C. Eskew, E.A. Balinandi, S. Mulei, S. Kayiwa, J. Klena, J.D. Shoemaker, T.R. Whitmer, S.L.M. Montgomery, J.M. Schieffelin, J. Lutwama, J. Muruta, A. Bosa, H.K. Nuismer, S.L. Oyola, Samuel O. Breiman, R.F. Njenga, M.K. rift valley fever zoonoses Introduction: Recent Rift Valley fever (RVF) epidemiology in eastern Africa region is characterized by widening geographic range and increasing frequency of small disease clusters. Here we conducted studies in the southwestern (SW) Uganda region that has since 2016 reported increasing RVF activities. Methods: A 22-month long hospital-based study in three districts of SW Uganda targeting patients with acute febrile illness (AFI) or unexplained bleeding was followed by a cross-sectional population-based human-animal survey. We then estimated RVFV force of infection (FOI) and yearly cases using the age-structured seroprevalence data and conducted genomic phylodynamic modelling of RVFV isolates. Results: Overall RVF prevalence was 10.5% (205 of 1,968) among febrile or hemorrhagic cases, including 5% (100 of 1,968) with acute (PCR or IgM positive) infection, averaging 5 cases per month. Community-based seroprevalence of 11.8% (88/743) among humans and 14.6% (347/2,383) in livestock was observed. Expected yearly human RVF cases were 314-2,111 per 1,369 km2 in SW Uganda, up to 3-fold higher than the 0-711 yearly cases in comparable regions of Kenya and Tanzania. Viral genomic studies identified RVFV lineage C, sub-clade C.2.2, as the circulating strain in SW Uganda since 2019. Lineage C strain has undergone recent rapid evolution and clonal expansion resulting in four sub-clades, C.1.1, C.1.2, C.2.1, and C.2.2, that are adept at establishing endemicity in new territories. Conclusions: We demonstrate an atypical RVF hyperendemic region in SW Uganda characterized by sustained human clinical RVF cases, unusually high population prevalence, and high number of expected yearly human cases, associated in part with emergence of new RVFV sub-lineages. 2026-01-15 2025-08-06T07:53:22Z 2025-08-06T07:53:22Z Journal Article https://hdl.handle.net/10568/175998 en Open Access Oxford University Press Bakamutumaho, B., Juma, J., Clancey, E., Nyakarahuka, L., Situma, S., Odinoh, R., Dawa, J., Nasimiyu, C., Eskew, E.A., Balinandi, S., Mulei, S., Kayiwa, J., Klena, J.D., Shoemaker, T.R., Whitmer, S.L.M., Montgomery, J.M., Schieffelin, J., Lutwama, J., Muruta, A., Bosa, H.K., Nuismer, S.L., Oyola, S.O., Breiman, R.F. and Njenga, M.K. 2026. Hyperendemicity of Rift Valley fever in Southwestern Uganda associated with the rapidly evolving lineage C viruses. Journal of Infectious Diseases 233 (1): e77–e88.
spellingShingle rift valley fever
zoonoses
Bakamutumaho, B.
Juma, John
Clancey, E.
Nyakarahuka, L.
Situma, S.
Odinoh, R.
Dawa, J.
Nasimiyu, C.
Eskew, E.A.
Balinandi, S.
Mulei, S.
Kayiwa, J.
Klena, J.D.
Shoemaker, T.R.
Whitmer, S.L.M.
Montgomery, J.M.
Schieffelin, J.
Lutwama, J.
Muruta, A.
Bosa, H.K.
Nuismer, S.L.
Oyola, Samuel O.
Breiman, R.F.
Njenga, M.K.
Hyperendemicity of Rift Valley fever in Southwestern Uganda associated with the rapidly evolving lineage C viruses
title Hyperendemicity of Rift Valley fever in Southwestern Uganda associated with the rapidly evolving lineage C viruses
title_full Hyperendemicity of Rift Valley fever in Southwestern Uganda associated with the rapidly evolving lineage C viruses
title_fullStr Hyperendemicity of Rift Valley fever in Southwestern Uganda associated with the rapidly evolving lineage C viruses
title_full_unstemmed Hyperendemicity of Rift Valley fever in Southwestern Uganda associated with the rapidly evolving lineage C viruses
title_short Hyperendemicity of Rift Valley fever in Southwestern Uganda associated with the rapidly evolving lineage C viruses
title_sort hyperendemicity of rift valley fever in southwestern uganda associated with the rapidly evolving lineage c viruses
topic rift valley fever
zoonoses
url https://hdl.handle.net/10568/175998
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