Evaluating dengue burden in Africa in passive fever surveillance and seroprevalence studies: protocol of field studies of the Dengue Vaccine Initiative

Abstract

IntroductionDengue is an important and well-documented public health problem in the Asia-Pacific and Latin American regions. However, in Africa, information on disease burden is limited to case reports and reports of sporadic outbreaks, thus hindering the implementation of public health actions for disease control. To gather evidence on the undocumented burden of dengue in Africa, epidemiological studies with standardised methods were launched in three locations in Africa.Methods and analysisIn 2014–2017, the Dengue Vaccine Initiative initiated field studies at three sites in Ouagadougou, Burkina Faso; Lambaréné, Gabon and Mombasa, Kenya to obtain comparable incidence data on dengue and assess its burden through standardised hospital-based surveillance and community-based serological methods. Multidisciplinary measurements of the burden of dengue were obtained through field studies that included passive facility-based fever surveillance, cost-of-illness surveys, serological surveys and healthcare utilisation surveys. All three sites conducted case detection using standardised procedures with uniform laboratory assays to diagnose dengue. Healthcare utilisation surveys were conducted to adjust population denominators in incidence calculations for differing healthcare seeking patterns. The fever surveillance data will allow calculation of age-specific incidence rates and comparison of symptomatic presentation between patients with dengue and non-dengue using multivariable logistic regression. Serological surveys assessed changes in immune status of cohorts of approximately 3000 randomly selected residents at each site at 6-month intervals. The age-stratified serosurvey data will allow calculation of seroprevalence and force of infection of dengue. Cost-of-illness evaluations were conducted among patients with acute dengue by Rapid Diagnostic Test.Ethics and disseminationBy standardising methods to evaluate dengue burden across several sites in Africa, these studies will generate evidence for dengue burden in Africa and data will be disseminated as publication in peer-review journals in 2018.

Seroprevalence and factors associated with IgG anti‐DENV positivity in blood donors in Burkina Faso during the 2016 dengue outbreak and implications for blood supply

“…These findings were expected and reflect the cumulative results of the different epidemics that occurred since 2003. Dengue fever outbreaks were declared in Burkina Faso in 2013, 2015 and 2016 . Therefore, as only IgG antibodies were screened, our study detected all donors who have ever been in contact with DENVs, either before or during the 2016 outbreak, and who still have a detectable title of circulating IgG anti‐DENVs.…”

“…Burkina Faso, located in West Africa, is part of the Soudano‐Sahelian area, with a rainy season from May to October (with a mean temperature of 28°C or 82 °F) and a dry season comprised of a cold period from December to February (minimum average temperature of 16°C or 61 °F) and a hot one, which runs from March to May, when the temperature can reach as high as 43°C or 109 °F …”

“…Therefore, it seems necessary to update the seroprevalence and factors associated with anti-DENV antibody positivity among blood donors and to discuss their implications for blood supply. 36 With an estimated population of 19 034 397 in 2016, 37 the country is mainly rural; only about 29% of the population lived in urban areas in 2014. However, Burkina Faso is urbanising rapidly and is the fourth country with the fastest urbanisation in the last quarter of a century.…”

A Mapping Review on Urban Landscape Factors of Dengue Retrieved from Earth Observation Data, GIS Techniques, and Survey Questionnaires

“…Relationships were not identified for individual dengue cases, except in id 22 (human mobility patterns of recently DENV-infected subjects). Since we considered data from survey questionnaires, a large number of relationships were identified at fine scale household-level, where the authors mainly considered the influence of house type and characteristics in the dengue transmission process, and exposure to Aedes bites by including entomological observations (ids: 1,4,8,12,13,20,25,26,34,35,48,52,55,60,68,75,77). Urban administrative divisions were often considered because (i) they represented the legal unit of dengue cases reports (ii) other datasets, such as demographic or socio-economic data, were aggregated and available at the same levels.…”

Detection of dengue virus type 2 of Indian origin in acute febrile patients in rural Kenya

“…Family Flaviviridae, genus Flavivirus, includes important mosquito-borne human pathogens such as the yellow fever, Zika, West Nile and dengue viruses, all found in Africa [1]. Dengue viruses (DENV-1 to 4) have a significant impact on public health globally, but their impact in Africa is less characterized, and the available information and sequence data are fragmented [2,3].…”