Evasius Bauni

Incidence of clinically significant bacteraemia in children who present to hospital in Kenya: community-based observational study.

BACKGROUND Estimates of the burden of invasive bacterial disease in sub-Saharan Africa have previously relied on selected groups of patients, such as inpatients; they are, therefore, probably underestimated, potentially hampering vaccine implementation. Our aim was to assess the incidence of bacteraemia in all children presenting to a hospital in Kenya, irrespective of clinical presentation or decision to admit. METHODS We did a community-based observational study for which we cultured blood from 1093 children who visited a Kenyan hospital outpatient department. We estimated bacteraemia incidence with a Demographic Surveillance System, and investigated the clinical significance of bacteraemia and the capacity of clinical signs to identify cases. RESULTS The yearly incidence of bacteraemia per 100,000 children aged younger than 2 years and younger than 5 years was 2440 (95% CI 1307-3573) and 1192 (692-1693), respectively. Incidence of pneumococcal bacteraemia was 597 (416-778) per 100,000 person-years of observation in children younger than age 5 years. Three-quarters of episodes had a clinical focus or required admission, or both; one in six was fatal. After exclusion of children with occult bacteraemia, the incidence of clinically significant bacteraemia per 100,000 children younger than age 2 years or 5 years fell to 1741 (790-2692) and 909 (475-1343), respectively, and the yearly incidence of clinically significant pneumococcal bacteraemia was 436 (132-739) per 100,000 children younger than 5 years old. Clinical signs identified bacteraemia poorly. INTERPRETATION Clinically significant bacteraemia in children in Kilifi is twice as common, and pneumococcal bacteraemia four times as common, as previously estimated. Our data support the introduction of pneumococcal vaccine in sub-Saharan Africa.

Profile: The Kilifi Health and Demographic Surveillance System (KHDSS)

Summary The Kilifi Health and Demographic Surveillance System (KHDSS), located on the Indian Ocean coast of Kenya, was established in 2000 as a record of births, pregnancies, migration events and deaths and is maintained by 4-monthly household visits. The study area was selected to capture the majority of patients admitted to Kilifi District Hospital. The KHDSS has 260 000 residents and the hospital admits 4400 paediatric patients and 3400 adult patients per year. At the hospital, morbidity events are linked in real time by a computer search of the population register. Linked surveillance was extended to KHDSS vaccine clinics in 2008. KHDSS data have been used to define the incidence of hospital presentation with childhood infectious diseases (e.g. rotavirus diarrhoea, pneumococcal disease), to test the association between genetic risk factors (e.g. thalassaemia and sickle cell disease) and infectious diseases, to define the community prevalence of chronic diseases (e.g. epilepsy), to evaluate access to health care and to calculate the operational effectiveness of major public health interventions (e.g. conjugate Haemophilus influenzae type b vaccine). Rapport with residents is maintained through an active programme of community engagement. A system of collaborative engagement exists for sharing data on survival, morbidity, socio-economic status and vaccine coverage.

Active convulsive epilepsy in a rural district of Kenya: a study of prevalence and possible risk factors

BACKGROUND Few large-scale studies of epilepsy have been done in sub-Saharan Africa. We aimed to estimate the prevalence of, treatment gap in, and possible risk factors for active convulsive epilepsy in Kenyan people aged 6 years or older living in a rural area. METHODS We undertook a three-phase screening survey of 151,408 individuals followed by a nested community case-control study. Treatment gap was defined as the proportion of cases of active convulsive epilepsy without detectable amounts of antiepileptic drugs in blood. FINDINGS Overall prevalence of active convulsive epilepsy was 2.9 per 1000 (95% CI 2.6-3.2); after adjustment for non-response and sensitivity, prevalence was 4.5 per 1000 (4.1-4.9). Substantial heterogeneity was noted in prevalence, with evidence of clustering. Treatment gap was 70.3% (65.9-74.5), with weak evidence of a difference by sex and area. Adjusted odds of active convulsive epilepsy for all individuals were increased with a family history of non-febrile convulsions (odds ratio 3.3, 95% CI 2.4-4.7; p<0.0001), family history of febrile convulsions (14.6, 6.3-34.1; p<0.0001), history of both seizure types (7.3, 3.3-16.4; p<0.0001), and previous head injury (4.1, 2.1-8.1; p<0.0001). Findings of multivariable analyses in children showed that adverse perinatal events (5.7, 2.6-12.7; p<0.0001) and the childs mother being a widow (5.1, 2.4-11.0; p<0.0001) raised the odds of active convulsive epilepsy. INTERPRETATION Substantial heterogeneity exists in prevalence of active convulsive epilepsy in this rural area in Kenya. Assessment of prevalence, treatment use, and demographic variation in screening response helped to identify groups for targeted interventions. Adverse perinatal events, febrile illness, and head injury are potentially preventable associated factors for epilepsy in this region.

A micro-epidemiological analysis of febrile malaria in Coastal Kenya showing hotspots within hotspots

Malaria transmission is spatially heterogeneous. This reduces the efficacy of control strategies, but focusing control strategies on clusters or ‘hotspots’ of transmission may be highly effective. Among 1500 homesteads in coastal Kenya we calculated (a) the fraction of febrile children with positive malaria smears per homestead, and (b) the mean age of children with malaria per homestead. These two measures were inversely correlated, indicating that children in homesteads at higher transmission acquire immunity more rapidly. This inverse correlation increased gradually with increasing spatial scale of analysis, and hotspots of febrile malaria were identified at every scale. We found hotspots within hotspots, down to the level of an individual homestead. Febrile malaria hotspots were temporally unstable, but 4 km radius hotspots could be targeted for 1 month following 1 month periods of surveillance. DOI: http://dx.doi.org/10.7554/eLife.02130.001

Cause-specific childhood mortality in Africa and Asia: evidence from INDEPTH health and demographic surveillance system sites

Background Because most deaths in Africa and Asia are not well documented, estimates of mortality are often made using scanty data. The INDEPTH Network works to alleviate this problem by collating detailed individual data from defined Health and Demographic Surveillance sites. By registering all deaths over time and carrying out verbal autopsies to determine cause of death across many such sites, using standardised methods, the Network seeks to generate population-based mortality statistics that are not otherwise available. Objective To build a large standardised mortality database from African and Asian sites, detailing the relevant methods, and use it to describe cause-specific mortality patterns. Design Individual demographic and verbal autopsy (VA) data from 22 INDEPTH sites were collated into a standardised database. The INDEPTH 2013 population was used for standardisation. The WHO 2012 VA standard and the InterVA-4 model were used for assigning cause of death. Results A total of 111,910 deaths occurring over 12,204,043 person-years (accumulated between 1992 and 2012) were registered across the 22 sites, and for 98,429 of these deaths (88.0%) verbal autopsies were successfully completed. There was considerable variation in all-cause mortality between sites, with most of the differences being accounted for by variations in infectious causes as a proportion of all deaths. Conclusions This dataset documents individual deaths across Africa and Asia in a standardised way, and on an unprecedented scale. While INDEPTH sites are not constructed to constitute a representative sample, and VA may not be the ideal method of determining cause of death, nevertheless these findings represent detailed mortality patterns for parts of the world that are severely under-served in terms of measuring mortality. Further papers explore details of mortality patterns among children and specifically for NCDs, external causes, pregnancy-related mortality, malaria, and HIV/AIDS. Comparisons will also be made where possible with other findings on mortality in the same regions. Findings presented here and in accompanying papers support the need for continued work towards much wider implementation of universal civil registration of deaths by cause on a worldwide basis.Background Because most deaths in Africa and Asia are not well documented, estimates of mortality are often made using scanty data. The INDEPTH Network works to alleviate this problem by collating detailed individual data from defined Health and Demographic Surveillance sites. By registering all deaths over time and carrying out verbal autopsies to determine cause of death across many such sites, using standardised methods, the Network seeks to generate population-based mortality statistics that are not otherwise available. Objective To build a large standardised mortality database from African and Asian sites, detailing the relevant methods, and use it to describe cause-specific mortality patterns. Design Individual demographic and verbal autopsy (VA) data from 22 INDEPTH sites were collated into a standardised database. The INDEPTH 2013 population was used for standardisation. The WHO 2012 VA standard and the InterVA-4 model were used for assigning cause of death. Results A total of 111,910 deaths occurring over 12,204,043 person-years (accumulated between 1992 and 2012) were registered across the 22 sites, and for 98,429 of these deaths (88.0%) verbal autopsies were successfully completed. There was considerable variation in all-cause mortality between sites, with most of the differences being accounted for by variations in infectious causes as a proportion of all deaths. Conclusions This dataset documents individual deaths across Africa and Asia in a standardised way, and on an unprecedented scale. While INDEPTH sites are not constructed to constitute a representative sample, and VA may not be the ideal method of determining cause of death, nevertheless these findings represent detailed mortality patterns for parts of the world that are severely under-served in terms of measuring mortality. Further papers explore details of mortality patterns among children and specifically for NCDs, external causes, pregnancy-related mortality, malaria, and HIV/AIDS. Comparisons will also be made where possible with other findings on mortality in the same regions. Findings presented here and in accompanying papers support the need for continued work towards much wider implementation of universal civil registration of deaths by cause on a worldwide basis.

Geographic access to care is not a determinant of child mortality in a rural Kenyan setting with high health facility density

BackgroundPolicy-makers evaluating country progress towards the Millennium Development Goals also examine trends in health inequities. Distance to health facilities is a known determinant of health care utilization and may drive inequalities in health outcomes; we aimed to investigate its effects on childhood mortality.MethodsThe Epidemiological and Demographic Surveillance System in Kilifi District, Kenya, collects data on vital events and migrations in a population of 220,000 people. We used Geographic Information Systems to estimate pedestrian and vehicular travel times to hospitals and vaccine clinics and developed proportional-hazards models to evaluate the effects of travel time on mortality hazard in children less than 5 years of age, accounting for sex, ethnic group, maternal education, migrant status, rainfall and calendar time.ResultsIn 2004-6, under-5 and under-1 mortality ratios were 65 and 46 per 1,000 live-births, respectively. Median pedestrian and vehicular travel times to hospital were 193 min (inter-quartile range: 125-267) and 49 min (32-72); analogous values for vaccine clinics were 47 (25-73) and 26 min (13-40). Infant and under-5 mortality varied two-fold across geographic locations, ranging from 34.5 to 61.9 per 1000 child-years and 8.8 to 18.1 per 1000, respectively. However, distance to health facilities was not associated with mortality. Hazard Ratios (HR) were 0.99 (95% CI 0.95-1.04) per hour and 1.01 (95% CI 0.95-1.08) per half-hour of pedestrian and vehicular travel to hospital, respectively, and 1.00 (95% CI 0.99-1.04) and 0.97 (95% CI 0.92-1.05) per quarter-hour of pedestrian and vehicular travel to vaccine clinics in children <5 years of age.ConclusionsSignificant spatial variations in mortality were observed across the area, but were not correlated with distance to health facilities. We conclude that given the present density of health facilities in Kenya, geographic access to curative services does not influence population-level mortality.

Validating physician-certified verbal autopsy and probabilistic modeling (InterVA) approaches to verbal autopsy interpretation using hospital causes of adult deaths

BackgroundThe most common method for determining cause of death is certification by physicians based either on available medical records, or where such data are not available, through verbal autopsy (VA). The physician-certification approach is costly and inconvenient; however, recent work shows the potential of a computer-based probabilistic model (InterVA) to interpret verbal autopsy data in a more convenient, consistent, and rapid way. In this study we validate separately both physician-certified verbal autopsy (PCVA) and the InterVA probabilistic model against hospital cause of death (HCOD) in adults dying in a district hospital on the coast of Kenya.MethodsBetween March 2007 and June 2010, VA interviews were conducted for 145 adult deaths that occurred at Kilifi District Hospital. The VA data were reviewed by a physician and the cause of death established. A range of indicators (including age, gender, physical signs and symptoms, pregnancy status, medical history, and the circumstances of death) from the VA forms were included in the InterVA for interpretation. Cause-specific mortality fractions (CSMF), Cohens kappa (κ) statistic, receiver operating characteristic (ROC) curves, sensitivity, specificity, and positive predictive values were applied to compare agreement between PCVA, InterVA, and HCOD.ResultsHCOD, InterVA, and PCVA yielded the same top five underlying causes of adult deaths. The InterVA overestimated tuberculosis as a cause of death compared to the HCOD. On the other hand, PCVA overestimated diabetes. Overall, CSMF for the five major cause groups by the InterVA, PCVA, and HCOD were 70%, 65%, and 60%, respectively. PCVA versus HCOD yielded a higher kappa value (κ = 0.52, 95% confidence interval [CI]: 0.48, 0.54) than the InterVA versus HCOD which yielded a kappa (κ) value of 0.32 (95% CI: 0.30, 0.38). Overall, (κ) agreement across the three methods was 0.41 (95% CI: 0.37, 0.48). The areas under the ROC curves were 0.82 for InterVA and 0.88 for PCVA. The observed sensitivities and specificities across the five major causes of death varied from 43% to 100% and 87% to 99%, respectively, for the InterVA/PCVA against the HCOD.ConclusionBoth the InterVA and PCVA compared well with the HCOD at a population level and determined the top five underlying causes of death in the rural community of Kilifi. We hope that our study, albeit small, provides new and useful data that will stimulate further definitive work on methods of interpreting VA data.

Incidence and clinical characteristics of group A rotavirus infections among children admitted to hospital in Kilifi, Kenya.

Background Rotavirus, predominantly of group A, is a major cause of severe diarrhoea worldwide, with the greatest burden falling on young children living in less-developed countries. Vaccines directed against this virus have shown promise in recent trials, and are undergoing effectiveness evaluation in sub-Saharan Africa. In this region limited childhood data are available on the incidence and clinical characteristics of severe group A rotavirus disease. Advocacy for vaccine intervention and interpretation of effectiveness following implementation will benefit from accurate base-line estimates of the incidence and severity of rotavirus paediatric admissions in relevant populations. The study objective was to accurately define the incidence and severity of group A rotavirus disease in a resource-poor setting necessary to make informed decisions on the need for vaccine prevention. Methods and Findings Between 2002 and 2004 we conducted prospective surveillance for group A rotavirus infection at Kilifi District Hospital in coastal Kenya. Children < 13 y of age were eligible as “cases” if admitted with diarrhoea, and “controls” if admitted without diarrhoea. We calculated the incidence of hospital admission with group A rotavirus using data from a demographic surveillance study of 220,000 people in Kilifi District. Of 15,347 childhood admissions 3,296 (22%) had diarrhoea, 2,039 were tested for group A rotavirus antigen and, of these, 588 (29%) were positive. 372 (63%) rotavirus-positive cases were infants. Of 620 controls 19 (3.1%, 95% confidence interval [CI] 1.9–4.7) were rotavirus positive. The annual incidence (per 100,000 children) of rotavirus-positive admissions was 1,431 (95% CI 1,275–1,600) in infants and 478 (437–521) in under-5-y-olds, and highest proximal to the hospital. Compared to children with rotavirus-negative diarrhoea, rotavirus-positive cases were less likely to have coexisting illnesses and more likely to have acidosis (46% versus 17%) and severe electrolyte imbalance except hyponatraemia. In-hospital case fatality was 2% among rotavirus-positive and 9% among rotavirus-negative children. Conclusions In Kilifi > 2% of children are admitted to hospital with group A rotavirus diarrhoea in the first 5 y of life. This translates into over 28,000 vaccine-preventable hospitalisations per year across Kenya, and is likely to be a considerable underestimate. Group A rotavirus diarrhoea is associated with acute life-threatening metabolic derangement in otherwise healthy children. Although mortality is low in this clinical research setting this may not be generally true in African hospitals lacking rapid and appropriate management.

Excess child mortality after discharge from hospital in Kilifi, Kenya: a retrospective cohort analysis.

OBJECTIVE To explore excess paediatric mortality after discharge from Kilifi District Hospital, Kenya, and its duration and risk factors. METHODS Hospital and demographic data were used to describe post-discharge mortality and survival probability in children aged < 15 years, by age group and clinical syndrome. Cox regression models were developed to identify risk factors. FINDINGS In 2004-2008, approximately 111,000 children were followed for 555,000 person-years. We analysed 14,971 discharges and 535 deaths occurring within 365 days of discharge. Mortality was higher in the post-discharge cohort than in the community cohort (age-adjusted rate ratio, RR: 7.7; 95% confidence interval, CI: 6.6-8.9) and declined little over time. An increased post-discharge mortality hazard was found in children aged < 5 years with the following: weight-for-age Z score < -4 (hazard ratio, HR: 6.5); weight-for-age Z score > -4 but < -3 (HR: 3.4); hypoxia (HR: 2.3); bacteraemia (HR: 1.8); hepatomegaly (HR: 2.3); jaundice (HR: 1.8); hospital stay > 13 days (HR: 1.8). Older age was protective (reference < 1 month): 6-23 months, HR: 0.8; 2-4 years, HR: 0.6. Children with at least one risk factor accounted for 545 (33%) of the 1655 annual discharges and for 39 (47%) of the 83 discharge-associated deaths. CONCLUSION Hospital admission selects vulnerable children with a sustained increased risk of dying. The risk factors identified provide an empiric basis for effective outpatient follow-up.

Sensitivity of hospital-based surveillance for severe disease: a geographic information system analysis of access to care in Kilifi district, Kenya

OBJECTIVE To explore the relationship between homestead distance to hospital and access to care and to estimate the sensitivity of hospital-based surveillance in Kilifi district, Kenya. METHODS In 2002-2006, clinical information was obtained from all children admitted to Kilifi District Hospital and linked to demographic surveillance data. Travel times to the hospital were calculated using geographic information systems and regression models were constructed to examine the relationships between travel time, cause-specific hospitalization rates and probability of death in hospital. Access to care ratios relating hospitalization rates to community mortality rates were computed and used to estimate surveillance sensitivity. FINDINGS The analysis included 7200 admissions (64 per 1000 child-years). Median pedestrian and vehicular travel times to hospital were 237 and 61 minutes, respectively. Hospitalization rates decreased by 21% per hour of travel by foot and 28% per half hour of travel by vehicle. Distance decay was steeper for meningitis than for pneumonia, for females than for males, and for areas where mothers had less education on average. Distance was positively associated with the probability of dying in hospital. Overall access to care ratios, which represent the probability that a child in need of hospitalization will have access to care at the hospital, were 51-58% for pneumonia and 66-70% for meningitis. CONCLUSION In this setting, hospital utilization rates decreased and the severity of cases admitted to hospital increased as distance between homestead and hospital increased. Access to hospital care for children living in remote areas was low, particularly for those with less severe conditions. Distance decay was attenuated by increased levels of maternal education. Hospital-based surveillance underestimated pneumonia and meningitis incidence by more than 45% and 30%, respectively.