Zika: Estimating the transmission and case burden of Zika virus in Kenya
Lead Research Organisation:
University of Oxford
Department Name: UNLISTED
Abstract
Abstracts are not currently available in GtR for all funded research. This is normally because the abstract was not required at the time of proposal submission, but may be because it included sensitive information such as personal details.
Technical Summary
Zika virus (ZIKV) was discovered in Uganda, and given the presence of vectors throughout
East Africa it is likely to be endemic in the region. High ZIKV antibody seroprevalence,
~50%, was reported in coastal Kenya in 1970, where coincident transmission of other
arboviruses also occurs. However, this may be due to cross-reactivity with other flaviviruses
and the epidemiology of ZIKV in East Africa remains unknown. On examination of data in
Kilifi Hospital on the Kenyan coast we find a 1% prevalence of severe microcephaly (defined
by interbio growth standards adjusting for gestational age and birthweight), which is far
higher than the expected prevalence of 0.1% but we do not know if this is attributable to
ZIKV.
To address these knowledge gaps we will utilise a unique biobank of samples at the Kenya
Medical Research Institute-Wellcome Trust Research Programme (KWTRP) collected over a
25-year period from coastal Kenya residents. The biobank is a sample archive of >100k acute
hospital admissions, paired maternal and cord blood from >10k deliveries, longitudinal cohort
samples from >2k individuals, and a large archive of local mosquito collections. Hospital case
records and other metadata are available for all these samples.
Using qRT-PCR and plaque reduction neutralisation assays (PRNT) we will determine the case
burden of ZIKV in matched case-control studies of: 1) cord blood samples for microcephalic
vs. normocephalic births, 2) plasma samples for acute undifferentiated fevers vs. community
controls, and 3) perform qRT-PCR assessments of Aedes mosquito collections for ZIKV. In
addition to genome sequencing of any qRT-PCR positive samples, PRNT on co-circulating
flaviviruses will be performed to ensure diagnostic accuracy. Together, this will provide the
first comprehensive analysis of ZIKV transmission and case burden in East Africa.
East Africa it is likely to be endemic in the region. High ZIKV antibody seroprevalence,
~50%, was reported in coastal Kenya in 1970, where coincident transmission of other
arboviruses also occurs. However, this may be due to cross-reactivity with other flaviviruses
and the epidemiology of ZIKV in East Africa remains unknown. On examination of data in
Kilifi Hospital on the Kenyan coast we find a 1% prevalence of severe microcephaly (defined
by interbio growth standards adjusting for gestational age and birthweight), which is far
higher than the expected prevalence of 0.1% but we do not know if this is attributable to
ZIKV.
To address these knowledge gaps we will utilise a unique biobank of samples at the Kenya
Medical Research Institute-Wellcome Trust Research Programme (KWTRP) collected over a
25-year period from coastal Kenya residents. The biobank is a sample archive of >100k acute
hospital admissions, paired maternal and cord blood from >10k deliveries, longitudinal cohort
samples from >2k individuals, and a large archive of local mosquito collections. Hospital case
records and other metadata are available for all these samples.
Using qRT-PCR and plaque reduction neutralisation assays (PRNT) we will determine the case
burden of ZIKV in matched case-control studies of: 1) cord blood samples for microcephalic
vs. normocephalic births, 2) plasma samples for acute undifferentiated fevers vs. community
controls, and 3) perform qRT-PCR assessments of Aedes mosquito collections for ZIKV. In
addition to genome sequencing of any qRT-PCR positive samples, PRNT on co-circulating
flaviviruses will be performed to ensure diagnostic accuracy. Together, this will provide the
first comprehensive analysis of ZIKV transmission and case burden in East Africa.
Organisations
People |
ORCID iD |
Publications
Barsosio HC
(2019)
Congenital microcephaly unrelated to flavivirus exposure in coastal Kenya.
in Wellcome open research
Kamau E
(2019)
Complete Genome Sequences of Dengue Virus Type 2 Strains from Kilifi, Kenya.
in Microbiology resource announcements