Dengue infection in patients with febrile illness and its relationship to climate factors: A case study in the city of Jeddah, Saudi Arabia, for the period 2010-2014.

Dengue is an important global arboviral disease with expanding geographical range. It is a major public health concern in Western Saudi Arabia since its first detection in the city of Jeddah in 1994. In this retrospective study, we examined dengue incidence among febrile patients suspected for acute dengue infection at King Abdulaziz University Hospital, Jeddah from 2010 to 2014 and we tried to determine the effect of climate factors on dengue incidence in the city. Acute dengue incidence rates among clinically suspected patients showed annual variation with a range from 29.3% to 57%. Male gender and 11-30 years age range were found to be risk factors for dengue infection in Jeddah. While dengue infections can be detected throughout the year, most cases occurred between March and July with peaks in May and June. Seasonality of dengue was found to be significantly associated with the decrease in relative humidity and increase in temperature within the range of ∼25 °C to ∼33 °C but not extremely hot temperatures. Moreover, we found that rainfall during winter (November to February) has a significant lag effect on dengue infection among febrile patients in the city. Jeddah is the second largest city in Saudi Arabia and a major hub for pilgrims because of its close proximity to the holy sites in the Kingdom. The observed high rates of acute dengue infections clearly show the endemicity of dengue in Jeddah. The observed higher incidence rates at young age are expected to cause an increase in severe dengue cases in the future especially that multiple dengue serotypes are co-circulating in the city. Furthermore, the significant association between the different climate factors and dengue and their impact on the disease seasonality should help in the effort to implement effective control and management measures to reduce dengue burden in the Kingdom.