Prevalence and Distribution of Dengue, Chikungunya and Zika Arboviruses among Non-Measles Febrile Rash Cases in Selected Regions of Kenya: 2008-2014

Abstract

In Kenya, 50-60% of suspected measles cases remain undiagnosed as their etiology remains unknown. Clinical symptoms of rash and fever are common manifestations of several infectious disease etiologies, including arboviruses and malaria. Lack of diagnostic capacity has led to the under-reporting of specific causes of febrile rash illness, including arbovirus infections in Kenya. This study aimed to determine the recent and past circulation of arboviral infections amongst suspected cases of measles in Kenya which confirmed negative IgM for measles as well as rubella serological assays. A retrospective study was conducted on 392 randomly selected serum samples collected between 2008 and 2014 from health facilities in Nairobi, North-Eastern and Coastal regions of Kenya. Samples were screened for the presence of IgG and IgM antibodies against dengue, chikungunya, and Zika viruses by Enzyme-Linked Immuno-sorbent Assay (ELISA). Positive samples by ELISA were confirmed by Plaque Reduction Neutralization Test (PRNT) for samples that were positive for either dengue (DEN), Zika (ZIK), or chikungunya (CHIK) viruses. Out of the 392 samples, 5(45.5%) were confirmed to have an active infection of DEN, while 1(0.3%) had an active infection of CHIK and 3 had an active infection of ZIK. Past infection of DEN was confirmed in 17 (56.7%) while 1 (10.0%) sample was positive for CHIKV. Other viruses included were West-Nile (WN), Yellow Fever (YF), Sindbis (SIN), Semliki Forest (SF) and O’nyong Nyong (ONN) viruses. 9(90.0%) samples were confirmed to be ONN, 3 (10.0%) to be WN and 2 (6.7%) to be YF. Dengue, chikungunya and Zika were detected in all years of study 2008-2014 and all study sites except Tana-River and Wajir Counties. The results showed that the prevalence of CHIK and DEN was significantly higher in those aged 14-60 years. The study confirms patients' exposure to these arboviral infections DEN, ZIK and CHIK arboviruses in Nairobi, North-Eastern and Coast Regions. The study recommends that arbovirus diagnosis be included in a comprehensive differential diagnosis for cases presenting with fever and rash from suspected measles cases. Additionally, clinicians should be sensitized to consider testing for arboviruses for those fever and rash cases that are negative for measles and rubella.