Laboratory-Enhanced Dengue Sentinel Surveillance in Colombo District, Sri Lanka: 2012-2014

Abstract

IntroductionDengue has emerged as a significant public health problem in Sri Lanka. Historically surveillance was passive, with mandatory dengue notifications based on clinical diagnosis with only limited laboratory confirmation. To obtain more accurate data on the disease burden of dengue, we set up a laboratory-based enhanced sentinel surveillance system in Colombo District. Here we describe the study design and report our findings of enhanced surveillance in the years 2012–2014.MethodsThree outpatient clinics and three government hospitals in Colombo District that covered most of the Colombo metropolitan area were selected for the sentinel surveillance system. Up to 60 patients per week presenting with an undifferentiated fever were enrolled. Acute blood samples from each patient were tested by dengue specific PCR, NS1 ELISA and IgM ELISA. A sub-set of samples was sent to Duke-NUS Singapore for quality assurance, virus isolation and serotyping. Trained medical research assistants used a standardized case report form to record clinical and epidemiological data. Clinical diagnoses by the clinicians-in-charge were recorded for hospitalized cases.ResultsOf 3,127 febrile cases, 43.6% were PCR and/or NS1 positive for dengue. A high proportion of lab confirmed dengue was observed from inpatients (IPD) (53.9%) compared to outpatient (clinics in hospitals and general practice) (7.6%). Dengue hemorrhagic fever (DHF) was diagnosed in 11% of patients at the time of first contact, and the median day of illness at time of presentation to the sentinel sites was 4. Dengue serotype 1 was responsible for 85% of the cases and serotype 4 for 15%. The sensitivity and specificity of the clinicians’ presumptive diagnosis of dengue was 84% and 34%, respectively.ConclusionDENV-1, and to a lesser degree DENV-4, infection were responsible for a high proportion of febrile illnesses in Colombo in the years 2012 to 2014. Clinicians’ diagnoses were associated with high sensitivity, but laboratory confirmation is required to enhance specificity.

A Spatial Hierarchical Analysis of the Temporal Influences of the El Niño-Southern Oscillation and Weather on Dengue in Kalutara District, Sri Lanka

“…Therefore unfortunately, since data with laboratory confirmed cases are not uniformly available for this analysis at the regional and sub-district level. Available scientific evidence suggests in Sri Lanka, that clinicians’ diagnosis for dengue at time of admission had a high sensitivity of 84.7% but the specificity of 32.5% is questionable [17]. However, this type of surveillance data is still the prevailing methods observing dengue disease patterns in most endemic countries.…”

“…DENV-1 replaced DENV-3 in 2009 triggering a wave of severe dengue epidemic in Sri Lanka. During 2012 to 2014 all laboratory confirmed cases were due to either DENV-1 or DENV-4, with DENV-1 being the predominant serotype (85%) [16,17]. In 2012, 44,456 cases were reported corresponding to an incidence rate of 220 per 100,000 population [18,19,20].…”

Novel tools for the surveillance and control of dengue: findings by the DengueTools research consortium

“…Quality assurance with a subset of samples sent to the Duke-NUS Laboratory ‘Emerging Infectious Diseases Program’ showed high agreement [7]. The improved RT-RPA as a rapid assay for dengue diagnosis is now routinely used for detection of DENV at the WHO Collaborating Center for Arbovirus Reference and Research (Dengue/Severe Dengue) at the University of Malay.…”

“…Historically surveillance was passive, with mandatory dengue notifications based on clinical diagnosis and limited laboratory confirmation. With DengueTools funds, we established laboratory-based enhanced sentinel surveillance in Colombo District [7]. Three outpatient clinics and three government hospitals from the Colombo metropolitan area were selected.…”

Evidence Decision-Making Policy Practice in Emerging Pandemics and Epidemics Threats Preparedness and Response Operations in Africa

“…Capability and capacity are there certain types of people or a particular skill set that would make an individual better able or equipped to engage in research-service collaborative research? Given this type of research takes place in the real life world of practice, there are some general transferable qualities that might be embodied in researchers, such as being: able to wear more comfortable in the field, good communicator with different audiences, able to go with the flow and be adaptable [35]. Whilst maintaining the standards of research rigour, able to manage conflict, be tenacious and creative.…”