Surveillance of dengue fever and domestic Aedes aegypti breeding sites in Jeddah, Saudi Arabia
Dengue fever is endemic in Jeddah since 1994. Indoor breeding premises are believed to be the main cause behind the recurrent and escalating dengue epidemics. Seasonal trend showed two peaks of dengue; a small peak in Nov through Jan and a larger peak in May through June. The primary vector in Jeddah is Aedes aegypti.
This study aims at studying the relation between larval house indices and dengue epidemics in Jeddah.
METHODS:
Indoor larval survey was conducted at the districts identified as high risk for dengue infection during 2012 and 2013. Positive breeding premises were identified and results were correlated with dengue cases.
RESULTS:
A total of 1928 clinically diagnosed cases of dengue fever were identified during 2012, in comparison to 6395 cases during 2013. Number of houses surveyed during 2012 and 2013 were 405644 and 294166 respectively. Up to 239827 water containers were examined during 2012, and 113674 during 2013. We found significant difference in House Index and Breteau Index between 2012 and 2013. Mean House index was 3.4 in 2012 and 5.8 in 2013 ( p< 0.01 ). Mean Breteau Index was 4.6 during 2012 and 9.6 during 2013 (p<0.01).
A statistically significant positive correlation was also detected between dengue cases and House Index with a gap of four international weeks during 2013 (Pearson r =.729, p<0.0001), while the correlation was positive only during the pre-epidemic period in 2012 (Pearson r =.699. p=0.012).
CONCLUSIONS:
Indoor breeding premises are the major risk for dengue infection in Jeddah. House index is a major parameter for detecting dengue outbreaks. Control measures should aim at household health education.