59Outbreak investigation of dengue fever in union council (UC) Bharakahu, Islamabad, Pakistan, 2019

Abstract

Abstract Background During third week of September 2019, lady health workers reported twelve suspected cases of dengue fever from UC Bharakahu, Islamabad (population 70,000) to health department. Outbreak investigation conducted with objectives to determine risk factors and recommend control measures. Methods Investigation conducted from 20th September to 04th November 2019. Case was defined as any resident of UC Bharakahu with fever and two or more of following signs/symptoms; headache, retro-orbital pain, arthralgia, myalgia, petechial rash with NS1 (Nonstructural Protein 1) positive during 12th August to 18th November 2019. Age and sex matched healthy controls recruited from same neighborhood. Blood samples from seven suspected cases sent for laboratory confirmation. Results Total 993 houses surveyed and 113 cases identified. Mean age was 34.2 years (range 13-90 years). Most affected age group was 35-44 years (Attack Rate 0.78%), Overall attack rate was 0.15%. Males were predominantly involved n = 70 (62%). Out of total cases, 34 (70%) had stagnant water inside and around houses (OR 2.0, CI 1.06-3.75, p < 0.005), 40 (35%) used repellent lotions (OR 0.55, CI 0.32-0.95, p < 0.05), 34 (30%) used insecticide spray (OR 0.35, CI 0.20-0.61, p < 0.05), 97 (86%) used full protective clothing (OR 0.22, CI 0.07-0.68, p < 0.05). All seven blood samples tested positive for NS-1 Ag. Conclusion Presence of stagnant rain water inside and around houses acted as breeding grounds for aedes aegypti mosquitoes and was most probable cause of outbreak. Following our recommendations, health department initiated mosquito breeding sites control activities through insecticide residual spray and advocacy on use of protective measures against mosquito bites. Key words Outbreak, dengue, stagnant water, Bhara Kahu, Islamabad, 2019