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Investigation of the First Reported Cases of West Nile Encephalitis in Saudi Arabia: Jeddah, March 2020.


West Nile Virus (WNV) infection is a mosquito borne disease which can cause death to humans and animals such as horses and birds. A confirmed case of WNV Encephalitis was reported from a hospital in Jeddah. The first reported confirmed case in the Kingdom of Saudi Arabia (KSA) was known cancer patient originally referred from Asser region with history of multiple blood transfusions. Objectives: The objectives were to determine the source of infection and route of transmission of the West Nile virus in Jeddah.


We conducted epidemiological, laboratory, and entomological investigations in both Jeddah and Aseer in February, 2020. Environmental and entomological assessments included inspection of index case house, kindergarten, relative's house in Jeddah, and the hospital premises for history of dead birds or animals, mosquito breeding sites. Laboratory analyses included serological, RT-PCR, isolating virus, among the case, family members, blood donors, and collected mosquitoes from both Jeddah and Aseer.


We found a female of 38 months known case of brain sarcoma on chemotherapy admitted to the National Guard Hospital in Jeddah, developed fever, stupor, encephalitis with seizures, weakness, and semi-coma in March 2020. Cerebrospinal fluid analysis revealed positive for WNV in May 2020. The entomological findings showed negative results for WNV RT-PCR among culex species, and the blood donors' laboratory findings showed 5 BDs tested IgG positive out of 22 blood donors.


Conclusively, the source of infection could be blood transfusions in NGHA-J. However, findings suggest the presence of WNV in Jeddah, where one of blood donors got infected. There might be chances of more cases have occurred and missed due to low suspicion by the clinical healthcare workers. Nevertheless, WNV has caused severe outbreaks when introduced to new areas and there is a need of further investigations in the Kingdom of Saudi Arabia.