Asymptomatic dengue infection in adults of major cities of Pakistan

Objective: To determine the asymptomatic dengue infection in adults of Pakistani population. Methods: This study was conducted in five major cities (Islamabad, Karachi, Lahore, Multan, and Peshawar) of Pakistan. A total of 5 230 adults aged 18 years and above without a history of dengue fever at any point in their life were enrolled from participating laboratories. Those who were confirmed for dengue previously were excluded. Of the total, 62.6% (n = 3 276) were male with an average age of 34.6 years. Participants were briefed about the objectives of the study, and written consent was obtained to perform dengue IgG test using enzyme linked immunosorbent assay. The brief information related to age, gender and area was also taken on proforma. Results: Overall 32.3% (n = 1 691) was having asymptomatic dengue infection which was 67.5% (n = 756) in Karachi followed by 39.1% (n = 391) in Islamabad, 29.9% (n = 316) in Lahore and 21% (n = 228) in Peshawar and none from Multan. More males were affected with asymptomatic dengue infection than females. The asymptomatic dengue infection was significantly higher in different cities; however, there was no significant difference with respect to age groups. Conclusions: The asymptomatic dengue infection is higher in cities i.e. Karachi, Islamabad and Lahore which are at risk of developing secondary dengue infections. There is a need of awareness among the public about secondary dengue infection.