“Preliminary Seroepidemiological survey of dengue infections in Pakistan, 2009-2014”

BACKGROUND: Dengue virus is the causative agent of dengue fever, a vector borne infection which causes self-limiting to life threatening disease in humans. A sero-epidemiological study was conducted to understand the current epidemiology of dengue virus in Pakistan which is now known as a dengue endemic country after its first reported outbreak in 1994. METHODS: To investigate the prevalence of dengue virus in Pakistan during 2009-2014, a total of 9,493 blood samples were screened for the detection of anti-dengue IgM antibodies using ELISA. Clinical and demographic features available with hospital records were reviewed to ascertain mortalities related to dengue hemorrhagic shock syndrome. RESULTS: Out of 9,493 samples tested, 37% (3,504) were found positive for anti-dengue IgM antibodies. Of the seropositive cases, 73.6% (2,578/3,504) were male and 26.4% (926/3,504) were female. The highest number (382/929; 41.1%) of sero-positive cases was observed among the individuals of age group 31-40 years. The highest number of symptomatic cases was reported in October (46%; 4,400/9,493), and the highest number of sero-positive cases among symptomatic cases was observed in November (45.7%; 806/1,764). Mean annual patient incidence (MAPI) during 2009-2014 in Pakistan remained 0.30 with the highest annual patient incidence (11.03) found in Islamabad. According to the available medical case record, 472 dengue related deaths were reported during 2009-2014. CONCLUSION: The data from earlier reports in Pakistan described the dengue virus incidence from limited areas of the country. Our findings are important considering the testing of clinical samples at a larger scale covering patients of vast geographical regions and warrants timely implementation of dengue vector surveillance and control programs. TRIAL REGISTRATION NUMBER: It is an epidemiological research study, so trial registration is not required. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s40249-017-0258-6) contains supplementary material, which is available to authorized users.