Serological evidence of exposure to Rift Valley, Dengue and Chikungunya Viruses among agropastoral communities in Manyara and Morogoro regions in Tanzania: A community survey

PLoS Negl Trop Dis. 2020 Jul 20;14(7):e0008061. doi: 10.1371/journal.pntd.0008061. eCollection 2020 Jul.

Abstract

Tanzania has recently experienced outbreaks of dengue in two coastal regions of Dar es Salaam and Tanga. Chikungunya and Rift Valley Fever outbreaks have also been recorded in the past decade. Little is known on the burden of the arboviral disease causing viruses (Dengue, Rift Valley and Chikungunya) endemically in the inter-epidemic periods. We aimed at determining the prevalence of the dengue, rift valley and chikungunya among humans in two geo ecologically distinct sites. The community-based cross-sectional study was conducted in Magugu in Manyara region and Wami-Dakawa in Morogoro region in Tanzania. Venous blood was collected from participants of all age groups, serum prepared from samples and subjected to ELISA tests for RVFV IgG/IgM, DENV IgG/IgM, and CHIKV IgM/IgG. Samples that were positive for IgM ELISA tests were subjected to a quantitative RT PCR for each virus. A structured questionnaire was used to collect socio-demographic information. Data analysis was performed by using SPSSv22. A total of 191 individuals from both sites participated in the study. Only one individual was CHIKV seropositive in Magugu, but none was seropositive or positive for either RVFV or DENV. Of the 122 individuals from Wami-Dakawa site, 16.39% (n = 20) had recent exposure to RVFV while 9.83% (n = 12) were seropositive for CHIKV. All samples were negative by RVFV and CHIKV qPCR. Neither infection nor exposure to DENV was observed in participants from both sites. Being more than 5 in a household, having no formal education and having recently travelled to an urban area were risk factors associated with RVFV and CHIKV seropositivity. We report a considerable exposure to RVFV and CHIKV among Wami-Dakawa residents during the dry season and an absence of exposure of the viruses among humans in Magugu site. In both sites, neither DENV exposure nor infection was detected.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Animals
  • Antibodies, Viral / blood*
  • Chikungunya Fever / blood*
  • Chikungunya Fever / epidemiology
  • Chikungunya Fever / virology
  • Chikungunya virus / immunology*
  • Chikungunya virus / physiology
  • Cross-Sectional Studies
  • Dengue / blood*
  • Dengue / epidemiology
  • Dengue / virology
  • Dengue Virus / immunology*
  • Dengue Virus / physiology
  • Female
  • Humans
  • Immunoglobulin M / blood
  • Male
  • Middle Aged
  • Rift Valley Fever / blood*
  • Rift Valley Fever / epidemiology
  • Rift Valley Fever / virology
  • Rift Valley fever virus / immunology*
  • Rift Valley fever virus / physiology
  • Seroepidemiologic Studies
  • Tanzania / epidemiology
  • Young Adult

Substances

  • Antibodies, Viral
  • Immunoglobulin M

Grants and funding

This study was conducted with financial support from the International Center for Genetic Engineering and Biotechnology (ICGEB), Grant #CRP/TZA18-04 to JOC and The East African Consortium for Clinical Research (EACCR-2) grant # EDCTP-RegNet2015-1104T through the KCRI NID node to BTM. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.