Abstract

The aim of this study was to determine the activity of the Rift Valley Fever Virus (RVFV) in non-exposed regions in Saudi Arabia following the outbreak that had occurred in the southwestern region of Saudi Arabia in 2000 - 2001. An Enzyme-Linked Immunosorbent Assay (ELISA) was used to detect anti-RVFV IgG antibodies among subjects working in abattoirs or adjacent livestock holding yards as a high risk group and healthy blood donors as a control group in seven non-epidemic regions of Saudi Arabia (Jeddah, Makkah, Al-Madina, Riyadh, Taif, Dammam, Yanbou). The serological tests were carried out at the Special Infectious Agents Unit, Biosafety Level 3, King Fahd Medical Research Centre, at King Abdulaziz University, Jeddah. A total of 1256 high-risk subjects (working in abattoirs or adjacent livestock holding yards) and 1216 blood donors were studied. Only 9 of 1256 (0.72%) high risk subjects and 2 of 1260 (0.16%) blood donors were RVFV IgG positive. All nine high risk RVFV-IgG positive subjects were of Bangladeshi nationality, whereas the two positive donors were of Saudi nationality from Dammam city. High risk practice that increases the risk of exposure to RVFV infection at work or at home was also studied. The reason for positive RVFV-IgG in the two supposedly-low risk blood donors was likely an old exposure to the virus in the epidemic regions (Jazan, Tihama of Asir, and Al-Qunfuda) back in 2000 - 2001. This could not be confirmed as it was not possible to contact these two donors to inquire about a past history of visiting any of the epidemic regions. The study confirms that the RVF epidemic in Saudi Arabia was confined to the epidemic regions (Jazan, Tihama of Asir, and Al-Qunfuda) with no serological evidence of spread of the infection among human subjects living outside the epicenters. The preventive measures undertaken at the time of the epidemic and thereafter by the concerned parties such as the Ministry of Health, Ministry of Agriculture, and Ministry of Municipality, clearly prevented the spread of RVFV to the rest of Saudi Arabia.

Key words: Rift valley fever virus, epidemic, Saudi Arabia.