Alkhurma hemorrhagic fever virus is one of the families Flaviviridae similar to Kyasanur Forest disease virus in India. It was discovered in Saudi Arabia for the first time in 1995 in a patient who died in 1994 and was suspected to have Congo-Crimean hemorrhagic fever. That patient was reported to develop fever after he slaughtered a sheep imported from Alkhurma city (near Al Taif city west of Saudi Arabia). Later, several cases were discovered, all of them were from Makkah region (Makkah, Jeddah and Taif). Recently, the disease had spread outside Makkah region as Najran region, which started to report several cases since 2003. This is the first study to be conducted on Alkhurma hemorrhagic fever virus (AHFV) outside Makkah region to describe the epidemiologic characteristics of this outbreak and investigate the possible factors associated with the occurrence of AHFV in Najran city (southern region of Saudi Arabia ) to assess the severity and the extent of this outbreak, to identify the source of this outbreak and the risk factors and to provide evidence-based recommendations for control of this disease and prevention of its recurrence.
Methodology
A case control study based on semi structured interviewing questionnaire and review of records of all the patients who were hospitalized and laboratory confirmed as positives for AHFV disease from 2006 to 2009. The study was conducted in Najran city. There were 6 districts from which the cases appeared, Al Balad, Al Hadhan, Al Jarbah, Dahthah, Al Gwailah and Al Mashaliah. Sampling was done as one case and two contacts from the relatives as controls who had the same risk factors to develop the disease. In this study, the total sample size reached 93 persons, 28 cases and 65 controls. The data were entered and analyzed by SPSS 17 program software.
Results
A total of 28 cases, reported between 1st January 2006 and April 2009, and 65 controls met the study criteria. Out of the cases, 11 had been hospitalized while 17 had subclinical disease; most of the cases occurred during the period from March to July. It was found that direct contact with domestic animals (OR=13.37; 95% CI: 2.96-69.06), feeding (OR=6.67; CI: 1.78-26.25) and slaughtering (OR=4.66; CI: 1.29-17.30) animals, dealing with raw meat products (OR=8.22; CI: 2.58-27.10) and drinking unpasteurized milk (OR=3.93; CI: 1.06-14.88) showed statistically significant relationship with Alkhurma fever. A statistically significant association between tick bite and development of the disease was also found (OR=11.48; 95% CI of 2.51-59.73) while no statistically significant difference as regards biting of mosquitoes. Finding from logistic regression models showed that statistically significant predictors of the disease included dealing with animals and tick bites only (adjusted OR=7.72; CI: 1.16-51.23 and adjusted OR=9.67; CI: 1.41-66.18 respectively).
Conclusion
AHFV is a zoonotic disease with clinical features ranging from sub-clinical asymptomatic to severe life-threatening complications. The study strongly indicates the association of different activity related to exposure to animals and tick bite with the infection.