Use of Population-based Surveillance to Determine the Incidence of Rotavirus Gastroenteritis in an Urban Slum and a Rural Setting in Kenya

Abstract

Background Rotavirus gastroenteritis is a major cause of mortality among children <2 years of age. Disease burden data are important for introducing and sustaining new rotavirus vaccines in immunization programs. Methods We analyzed population-based infectious disease surveillance data from 2007 to 2010 from Kenyan sites in rural and urban slum areas. Stool specimens were collected from patients of all ages presenting to study clinics with diarrheal disease and tested for rotavirus by enzyme immunoassay. Incidence rates were adjusted using data on healthcare utilization (from biweekly home visits) and proportion of stools collected at study clinics from patients meeting case definitions. Results Rotavirus was detected in 285 (9.0%) of 3174 stools tested, including 122 (11.9%) from children <5 years of age and 162 (7.6%) from participants ≥5 years of age. Adjusted incidence rates for infants were 13,419 and 12,135 per 100,000 person-years of observation in rural and urban areas, respectively. Adjusted incidence rates were high in adults across age ranges. The rates suggest that annually, among children <5 years of age, there are >54,500 cases of rotavirus-associated gastroenteritis in rural Nyanza Province and >16,750 cases in Nairobi urban slums. Conclusions Community-based surveillance in urban and rural Kenya suggests that rotavirus plays an important role as a cause of acute gastroenteritis in adults, as well as in children. In addition to substantially preventing illness and complications from diarrheal disease in children, rotavirus infant immunization has the potential of indirectly preventing diarrheal disease in older children and adults, assuming children are the predominant sources of transmission.

Epidemiology, Seasonality and Factors Associated with Rotavirus Infection among Children with Moderate-to-Severe Diarrhea in Rural Western Kenya, 2008–2012: The Global Enteric Multicenter Study (GEMS)

“…During the first 3 years of year surveillance, we found rotavirus prevalence rate of 14.2% in year 1 and which remained stable in year two (13.8%) but increased to 20.7% in year 3 among children seeking care at a hospital or health center for non-dysenteric MSD. Our prevalence rate of rotavirus among MSD patients <5 years in year one and two of the surveillance is slightly higher but remains comparable to a prevalence of 12% reported from a population-based surveillance study conducted in both urban slums in Nairobi and rural western Kenya [ 36 ] and to 13.5% from a similar study conducted in Nigeria [ 37 ]. Furthermore, our observed prevalence especially in year 3 is similar to that observed in other hospital-based studies conducted in the neighboring countries like Tanzania (21%) [ 10 ]and Ethiopia (21%) [ 38 ].…”

Population-Based Incidence Rates of Diarrheal Disease Associated with Norovirus, Sapovirus, and Astrovirus in Kenya

“…Nonetheless, the magnitude of these estimates suggests the significant burden of these enteric viruses on the people and healthcare system in Kenya and the importance of targeted public health interventions for these enteric viruses. Compared to the outpatient incidence of rotavirus estimated in the same sites among children aged <5 years from 2007 to 2010 (before introduction of rotavirus vaccine into the national immunization program in 2014) [ 14 ], the outpatient incidence of norovirus was estimated to be 10% higher in Lwak and 46% higher in Kibera among the same age group. Among the total population across all age groups, the outpatient incidence of norovirus was about 2-fold higher than that of rotavirus in both sites.…”

“…An important limitation of this study is the lack of non-diarrheal or healthy control specimens. As such, we were not able to adjust the attributable fraction to account for asymptomatic viral detection, as has been done previously [ 14 ]. However, we conservatively limited our incidence estimates for norovirus, sapovirus, and astrovirus to only include diarrhea patients that were not positive for another known pathogen (i.e., enteric bacteria or rotavirus), providing some reassurance that these were etiologic detections.…”

“…Kibera is an urban slum in Nairobi, which is the capital and the largest city in Kenya. The geographic characteristics of these surveillance areas have been described previously [ 14 , 15 ]. The study periods for this analysis was from June 2007 to October 2008 (one year and five months) in Lwak and from October 2006 to February 2009 (two years and five months) in Kibera.…”

Tuberculosis case finding using population-based disease surveillance platforms in urban and rural Kenya

“…As part of ongoing disease surveillance since 2005, participants in the PBIDS project were visited weekly or bi-weekly at home by field workers who used standardized questionnaires to gather information about any illnesses since the last home visit [ 25 , 30 – 32 ]. At the onset, the study focused on characterization of four syndromes, which were pneumonia, diarrhea febrile illness and jaundice.…”