Session:

Emerging Infectious Diseases

Abstract No.:

46.047

Title:

Laboratory confirmation of dengue-3 virus outbreak in Mandera, Northern Kenya, 2011

Author(s):

V. Ofula¹, C. Ochieng¹, S. Limbaso¹, E. Wurapa², R. Sang³, M. Obonyo⁴, E. Bii¹; ¹United States Army Medical Research Unit-Kenya, VHF Laboratory, Nairobi/KE, ²USAMRU-K, DEID, Nairobi/KE, ³Kenya Medical Research Institute, Center for Virus Research, Nairobi/KE, ⁴Ministry of Public Health and Sanitation, Field Epidemiology and Laboratory Traaining Program, Nairobi, N/A/KE

Abstract:

Background: Dengue a mosquito-borne viral infection is caused by four dengue virus serotypes (DENV-1, DENV-2, DENV-3, and DENV-4) that are antigenically distinct. All DENVs are transmitted to humans through the bite of infected mosquitoes, primarilyAedes aegyptiandAedes albopictusspecies. In September 2011, reports were received from Mandera District Disease surveillance office of an unusually high number of patients visiting health facilities, with high fever, severe arthralgia and myalgia with some reporting gingival and nasal hemorrhages. Most patients were negative for malaria, though they were treated with anti-malarial medicine with no improvement. An investigation was conducted to confirm and determine the cause of the illness.
Methods: Blood Samples from sick patients were collected and transported to the Arbovirus/Viral Hemorrhagic Fever (VHF) laboratory for arboviruses testing using enzyme linked immunosorbent assay-IgM (IgM-ELISA), real time reverse transcriptase polymerase chain reaction (rRT-PCR) and conventional reverse transcriptase polymerase chain reaction (RT-PCR).Virus isolation was also attempted in Vero cell lines
Results: A total of 43 blood samples were collected and tested. A total of 11 samples (25.6%) were positive for Dengue virus by IgM ELISA, 29 (67.4%) were positive for Dengue virus by real time PCR and 26/43 (60.5%) were positive were for Dengue-3 virus by conventional RT-PCR. Virus isolation was unsuccessful despite two passage attempts.
Conclusion: The outbreak that occurred in Mandera, northern Kenya was caused by Dengue virus. After molecular diagnosis, Dengue virus serotype 3 was the cause of the acute febrile illness. The disease was most likely imported from neighboring Somalia which had an ongoing outbreak since June 2011. This calls for the need for strengthened surveillance with strong laboratory capacity in the region to detect and respond to any potential outbreaks in future.