Risk Factors Associated with a Dengue Fever Outbreak in Islamabad, Pakistan: Case-Control Study

Abstract

Background On October 23, 2016, 79 dengue fever cases were reported from the Union Council Tarlai to Federal Disease Surveillance and Response Unit Islamabad. A team was established to investigate the suspected dengue outbreak. Objective The aim of this study was to determine the extent of the outbreak and identify the possible risk factors. Methods Active case finding was performed through a house-to-house survey. A case was defined as an acute onset of fever ≥38℃ in a resident of Tarlai from October 2 to November 11, 2016, with a positive dengue virus (nonstructural protein, NS-1) test and any of the two of following signs and symptoms: retroorbital/ocular pain, headache, rash, myalgia, arthralgia, and hemorrhagic manifestations. A structured questionnaire was used to collect data. Age- and sex-matched controls (1:1) were identified from residents in the same area as cases. Blood samples were taken and sent to the National Institute of Health for genotype identification. Results During the active case search, 145 cases of dengue fever were identified by surveying 928 houses from October 23 to November 11, 2016. The attack rate (AR) was 17.0/10,000. The mean age was 34.4 (SD 14.4) years. More than half of the cases were male (80/145, 55.2%). Among all cases, 29% belonged to the 25-34 years age group and the highest AR was found in the 35-44 years age group (35.6/10,000), followed by the 55-64 years age group (35.5/10,000). All five blood samples tested positive for NS-1 (genotype DENV-2). The most frequent presenting signs/symptoms were fever and headache (both 100%). Stagnant water around houses (odds ratio [OR] 4.86, 95% CI 2.94-8.01; P<.001), presence of flower pots in the home (OR 2.73, 95% CI 1.67-4.45; P<.001), and open water containers (OR 2.24, 95% CI 1.36-3.60; P<.001) showed higher odds among cases. Conversely, use of bed nets (OR 0.44, 95% CI 0.25-0.77; P=.003), insecticidal spray (OR 0.33, 95% CI 0.22-0.55; P<.001), door screens (OR 0.27, 95% CI 0.15-0.46; P<.001), mosquito coil/mat (OR 0.26, 95% CI 0.16-0.44; P<.001), and cleanliness of the house (OR 0.12, 95% CI 0.05-0.26; P<.001) showed significant protective effects. Conclusions Stagnant water acting as breeding grounds for vectors was identified as the probable cause of spread of the dengue outbreak. Establishment of surveillance and an early reporting system along with use of protective measures against the vector are strongly recommended.

Prevalence of dengue virus serotypes in dengue hemorrhagic fever patients of Peshawar, Pakistan

“…It was previously known that secondary DENV infection happening in the region which is endemic to DENV or areas affected by more than one serotype at a time which corresponds to a major public health risk and is also associated with the progression of disease from DF to DHF and DSS [13]. In the current study, we found DENV2 to be the predominant serotype involved in the dengue outbreaks in Peshawar in contrast to Suleiman et al [1].…”

“…Death toll due to Dengue is 73 till date. The majority of the positive cases were reported in Peshawar city [13]. The serotypes responsible for such cases were not yet analyzed.…”

Demographic and clinical variables in the dengue epidemic in Punjab, Pakistan

“…This is positively reinforced by another study which established that the most known signs and symptoms were fever, myalgia, headache, and retro-orbital pain. 11 Another study also demonstrated that signs and symptoms of dengue fever were high-grade fever, vomiting, abdominal pain, ascites, pleural effusion, GIT bleeding, gum bleeding, and skin bleeding. 15 A comparative study conducted in Bangladesh showed an increasing incidence of abdominal symptoms like abdominal pain anorexia, and diarrhea whereas a decreasing tendency was noticed in terms of hemorrhagic manifestations including melena, conjunctival hemorrhage, hemorrhagic sclera, or skin rash.…”

Frequency of Gastrointestinal Signs and Symptoms in Patients with Dengue Fever in Tertiary Care Hospital

“…Authors from Pakistan has conducted a survey on dengue virus prevalence and found that overall prevalence rate was 15.5% in Islamabad. 4 Another study from Pakistan has observed highest prevalence of dengue in Karachi and Lahore. 5 Most of the patients suffered are from young age group.…”