Kevin M. DeCock

Aflatoxin contamination of commercial maize products during an outbreak of acute aflatoxicosis in eastern and central Kenya.

In April 2004, one of the largest aflatoxicosis outbreaks occurred in rural Kenya, resulting in 317 cases and 125 deaths. Aflatoxin-contaminated homegrown maize was the source of the outbreak, but the extent of regional contamination and status of maize in commercial markets (market maize) were unknown. We conducted a cross-sectional survey to assess the extent of market maize contamination and evaluate the relationship between market maize aflatoxin and the aflatoxicosis outbreak. We surveyed 65 markets and 243 maize vendors and collected 350 maize products in the most affected districts. Fifty-five percent of maize products had aflatoxin levels greater than the Kenyan regulatory limit of 20 ppb, 35% had levels > 100 ppb, and 7% had levels > 1,000 ppb. Makueni, the district with the most aflatoxicosis case-patients, had significantly higher market maize aflatoxin than did Thika, the study district with fewest case-patients (geometric mean aflatoxin = 52.91 ppb vs. 7.52 ppb, p = 0.0004). Maize obtained from local farms in the affected area was significantly more likely to have aflatoxin levels > 20 ppb compared with maize bought from other regions of Kenya or other countries (odds ratio = 2.71; 95% confidence interval, 1.12–6.59). Contaminated homegrown maize bought from local farms in the affected area entered the distribution system, resulting in widespread aflatoxin contamination of market maize. Contaminated market maize, purchased by farmers after their homegrown supplies are exhausted, may represent a source of continued exposure to aflatoxin. Efforts to successfully interrupt exposure to aflatoxin during an outbreak must consider the potential role of the market system in sustaining exposure.

Case-control study of an acute aflatoxicosis outbreak, Kenya, 2004

Objectives: During January–June 2004, an aflatoxicosis outbreak in eastern Kenya resulted in 317 cases and 125 deaths. We conducted a case–control study to identify risk factors for contamination of implicated maize and, for the first time, quantitated biomarkers associated with acute aflatoxicosis. Design: We administered questionnaires regarding maize storage and consumption and obtained maize and blood samples from participants. Participants: We recruited 40 case-patients with aflatoxicosis and 80 randomly selected controls to participate in this study. Evaluations/Measurements: We analyzed maize for total aflatoxins and serum for aflatoxin B1–lysine albumin adducts and hepatitis B surface antigen. We used regression and survival analyses to explore the relationship between aflatoxins, maize consumption, hepatitis B surface antigen, and case status. Results: Homegrown (not commercial) maize kernels from case households had higher concentrations of aflatoxins than did kernels from control households [geometric mean (GM) = 354.53 ppb vs. 44.14 ppb; p = 0.04]. Serum adduct concentrations were associated with time from jaundice to death [adjusted hazard ratio = 1.3; 95% confidence interval (CI), 1.04–1.6]. Case patients had positive hepatitis B titers [odds ratio (OR) = 9.8; 95% CI, 1.5–63.1] more often than controls. Case patients stored wet maize (OR = 3.5; 95% CI, 1.2–10.3) inside their homes (OR = 12.0; 95% CI, 1.5–95.7) rather than in granaries more often than did controls. Conclusion: Aflatoxin concentrations in maize, serum aflatoxin B1–lysine adduct concentrations, and positive hepatitis B surface antigen titers were all associated with case status. Relevance: The novel methods and risk factors described may help health officials prevent future outbreaks of aflatoxicosis.

Health and nutritional status of orphans <6 years old cared for by relatives in western Kenya.

One of the consequences of the HIV/AIDS epidemic in sub‐Saharan Africa is the increase in the number of orphans, estimated to have reached 6–11% of children <15 years old in 2000. Orphans who stay in their communities may be at increased risk for poor health due to reduced circumstances and loss of parental care. We have used data from a population‐based study in rural western Kenya to compare basic health and nutritional indicators between non‐orphaned children <6 years old and children who lost either or both of their parents. In June 2000, all children <6 years old who had been recruited for a cross‐sectional survey in 60 villages of Rarieda Division, western Kenya, in June 1999 were invited to return for a follow‐up survey. Basic demographic characteristics, including the vital status of the childs parents, and health histories were requested from all 1190 participants of the follow‐up survey, along with a finger‐prick blood sample for determination of malaria parasite status and haemoglobin (Hb) levels. Height‐for‐age (H/A) and weight‐for‐height (W/H) Z‐scores were also calculated from anthropometric measurements. Overall, 7.9% of the children had lost one or both their parents (6.4% had lost their father, 0.8% had lost their mother and 0.7% had lost both parents). While there was no difference between orphans and non‐orphans regarding most of the key health indicators (prevalence of fever and malaria parasitaemia, history of illness, Hb levels, H/A Z scores), W/H Z‐scores in orphans were almost 0.3 standard deviations lower than those of non‐orphans. This association was more pronounced among paternal orphans and those who had lost a parent more than 1 year ago. These results suggest that the health status of surviving orphans living in their community is similar to that of the non‐orphan population, but longitudinal cohort studies should be conducted to determine better the overall impact of orphanhood on child health.

Profile: The KEMRI/CDC Health and Demographic Surveillance System—Western Kenya

The KEMRI/Centers for Disease Control and Prevention (CDC) Health and Demographic Surveillance System (HDSS) is located in Rarieda, Siaya and Gem Districts (Siaya County), lying northeast of Lake Victoria in Nyanza Province, western Kenya. The KEMRI/CDC HDSS, with approximately 220 000 inhabitants, has been the foundation for a variety of studies, including evaluations of insecticide-treated bed nets, burden of diarrhoeal disease and tuberculosis, malaria parasitaemia and anaemia, treatment strategies and immunological correlates of malaria infection, and numerous HIV, tuberculosis, malaria and diarrhoeal disease treatment and vaccine efficacy and effectiveness trials for more than a decade. Current studies include operations research to measure the uptake and effectiveness of the programmatic implementation of integrated malaria control strategies, HIV services, newly introduced vaccines and clinical trials. The HDSS provides general demographic and health information (such as population age structure and density, fertility rates, birth and death rates, in- and out-migrations, patterns of health care access and utilization and the local economics of health care) as well as disease- or intervention-specific information. The HDSS also collects verbal autopsy information on all deaths. Studies take advantage of the sampling frame inherent in the HDSS, whether at individual, household/compound or neighbourhood level.

Preventing mother-to-child transmission of HIV in Western Kenya: operational issues

Objectives:To improve uptake in a program to prevent mother-to-child HIV transmission and describe lessons relevant for prevention of mother-to-child transmission programs in resource-poor settings. Methods:Implementation of a pilot project that evaluates approaches to increase program uptake at health facility level at New Nyanza Provincial General Hospital, a public hospital in western Kenya, an area with high HIV prevalence. Client flow was revised to integrate counseling, HIV testing, and dispensing of single-dose nevirapine into routine antenatal services. The number of facilities providing PMCT services was expanded to increase district-wide coverage. Main outcome measures were uptake of counseling, HIV testing, nevirapine, and estimated program impact. Results:Uptake of counseling and testing improved from 55 to 68% (P < 0.001), nevirapine uptake from 57% to 70% (P < 0.001), and estimated program impact from 15% to 23% (P = 0.03). Aggregate reports compare well with computer-entered data. Conclusion:Addressing institutional factors can improve uptake, but expected program impact remains low for several reasons, including relatively low efficacy of the intervention and missed opportunities in the labor room.

High Prevalence of Pulmonary Tuberculosis and Inadequate Case Finding in Rural Western Kenya

RATIONALE Limited information exists on the prevalence of tuberculosis and adequacy of case finding in African populations with high rates of HIV. OBJECTIVES To estimate the prevalence of bacteriologically confirmed pulmonary tuberculosis (PTB) and the fraction attributable to HIV, and to evaluate case detection. METHODS Residents aged 15 years and older, from 40 randomly sampled clusters, provided two sputum samples for microscopy; those with chest radiograph abnormalities or symptoms suggestive of PTB provided one additional sputum sample for culture. MEASUREMENTS AND MAIN RESULTS PTB was defined by a culture positive for Mycobacterium tuberculosis or two positive smears. Persons with PTB were offered HIV testing and interviewed on care-seeking behavior. We estimated the population-attributable fraction of HIV on prevalent and notified PTB, the patient diagnostic rate, and case detection rate using provincial TB notification data. Among 20,566 participants, 123 had PTB. TB prevalence was 6.0/1,000 (95% confidence interval, 4.6-7.4) for all PTB and 2.5/1,000 (1.6-3.4) for smear-positive PTB. Of 101 prevalent TB cases tested, 52 (51%) were HIV infected, and 58 (64%) of 91 cases who were not on treatment and were interviewed had not sought care. Forty-eight percent of prevalent and 65% of notified PTB cases were attributable to HIV. For smear-positive and smear-negative PTB combined, the patient diagnostic rate was 1.4 cases detected per person-year among HIV-infected persons having PTB and 0.6 for those who were HIV uninfected, corresponding to case detection rates of 56 and 65%, respectively. CONCLUSIONS Undiagnosed PTB is common in this community. TB case finding needs improvement, for instance through intensified case finding with mobile smear microscopy services, rigorous HIV testing, and improved diagnosis of smear-negative TB.

First documentation of human Crimean-Congo hemorrhagic fever, Kenya.

To the Editor: On October 21, 2000, a previously healthy 25-year-old male farmer was admitted to a mission hospital in western Kenya with an acute hemorrhagic illness. Four days before admission, the patient had rapid onset of fever, headache, nausea, vomiting, severe muscle pains, and diarrhea, which became bloody. On admission his temperature was 36.4°C, pulse was 60/minute, respiratory rate was 20/minute, and blood pressure was 90/40 mm Hg. In addition to the signs and symptoms listed above, the only other abnormal finding on admission was neck stiffness. The differential diagnoses included bacterial dysentery and meningitis. Results of a blood smear for malaria parasites and Widal test for typhoid were negative, and cerebrospinal fluid and urine examinations were normal. The patient was treated with doxycycline, cotrimoxazole, metronidazole, and intravenous fluids. On the day after admission, the patient’s vomitus became blood stained and blood was passed rectally. The patient was isolated and strict barrier nursing implemented on the suspicion of viral hemorrhagic fever (VHF). Progressive hypotension developed, resistant to resuscitation efforts with intravenous fluids and corticosteroids, and later massive bleeding from the nose, mouth, and upper and lower gastrointestinal tract occurred. The patient died on the second day of admission, 6 days after onset of illness. A serum sample was sent to the Arbovirus and Viral Hemorrhagic Fever Reference Laboratory in Nairobi for diagnostic screening. Serologic tests in Nairobi were negative for yellow fever, dengue, West Nile, Chikungunya, and Rift Valley fever (immunoglobulin [Ig] M–capture enzyme-linked immunosorbent assay) and reverse transcriptase-polymerase chain reaction (RT-PCR) tests for flaviviruses, alphaviruses, and Bunyamwera serogroup bunyaviruses were also negative. RT-PCR for Crimean-Congo hemorrhagic fever virus (C-CHFV) was positive. Tests for anti-C-CHFV–specific IgM antibody by indirect immunofluorescence were negative. Virus isolation attempts were then terminated because the cultivation of C-CHFV (the presumptive cause) requires biosafety level 4 facilities. The specimen was submitted to the Special Pathogens Unit in Johannesburg for confirmation of the result. The sample was positive by RT-PCR for C-CHFV and was IgM and IgG antibody negative. No isolation of the virus could be made from the serum sample, possibly because it was received by the Johannesburg laboratory 8 days after initial collection and following freeze-thaw conditions. The specimen was was insufficient to attempt C-CHVF antigen detection assays. Sequencing of the RT-PCR amplicon confirmed C-CHFV. C-CHFV is a tick-borne virus of the genus Nairovirus, family Bunyaviridae, and is widely distributed throughout eastern Europe and the Crimea, to the Middle East and western China, Pakistan, and Africa. Natural hosts for this virus are varied (including wild and domestic animals and birds) and may reflect the feeding preferences of the host tick (1). While C-CHFV infections are rare in humans, the virus is notorious for nosocomial outbreaks of VHF, typically following admission of an index case to a health-care facility where VHF was not suspected, with mortality rates up to 40%. Previous evidence for C-CHFV in Kenya is limited and based on serology (human and bovine) and two isolations of C-CHFV from non-human sources (1,2). This report represents the first documented case of acute human C-CHFV infection in Kenya. The hospital concerned belongs to a VHF surveillance network serving to increase awareness and preparedness within Kenyan health-care facilities. In this case suspicion of VHF was raised, and the patient was immediately isolated, noninvasive procedures were instigated, and barrier nursing was implemented to prevent nosocomial transmission. No family or hospital staff member who had close contact with the patient became ill. Although VHFs are rare, this report stresses the need for health facilities in Kenya and East/Central Africa to include VHFs in their differential diagnosis of unexplained fever with hemorrhagic tendencies, as well as the utility of the surveillance network. The causative agents of Ebola hemorrhagic fever, Marburg hemorrhagic fever, C-CHFV, Rift Valley fever, and yellow fever are all endemic in East and Central Africa, and sporadic cases, as well as outbreaks, are likely to continue to occur in this region (3–5).

Population-Based Biochemistry, Immunologic and Hematological Reference Values for Adolescents and Young Adults in a Rural Population in Western Kenya

Background There is need for locally-derived age-specific clinical laboratory reference ranges of healthy Africans in sub-Saharan Africa. Reference values from North American and European populations are being used for African subjects despite previous studies showing significant differences. Our aim was to establish clinical laboratory reference values for African adolescents and young adults that can be used in clinical trials and for patient management. Methods and Findings A panel of 298, HIV-seronegative individuals aged 13–34 years was randomly selected from participants in two population-based cross-sectional surveys assessing HIV prevalence and other sexually transmitted infections in western Kenya. The adolescent (<18 years)-to-adults (≥18 years) ratio and the male-to-female ratio was 1∶1. Median and 95% reference ranges were calculated for immunohematological and biochemistry values. Compared with U.S-derived reference ranges, we detected lower hemoglobin (HB), hematocrit (HCT), red blood cells (RBC), mean corpuscular volume (MCV), neutrophil, glucose, and blood urea nitrogen values but elevated eosinophil and total bilirubin values. Significant gender variation was observed in hematological parameters in addition to T-bilirubin and creatinine indices in all age groups, AST in the younger and neutrophil, platelet and CD4 indices among the older age group. Age variation was also observed, mainly in hematological parameters among males. Applying U.S. NIH Division of AIDS (DAIDS) toxicity grading to our results, 40% of otherwise healthy study participants were classified as having an abnormal laboratory parameter (grade 1–4) which would exclude them from participating in clinical trials. Conclusion Hematological and biochemistry reference values from African population differ from those derived from a North American population, showing the need to develop region-specific reference values. Our data also show variations in hematological indices between adolescent and adult males which should be considered when developing reference ranges. This study provides the first locally-derived clinical laboratory reference ranges for adolescents and young adults in western Kenya.

Decreased Ebola Transmission after Rapid Response to Outbreaks in Remote Areas, Liberia, 2014.

Basic interventions and community acceptance can result in rapid control of outbreaks.

Differential of HIV prevalence in women and men who attended sexually transmitted disease clinics at HIV sentinel surveillance sites in Kenya, 1990-2001.

Several studies in sub-Saharan Africa have reported that HIV prevalence in young women is higher than in young men. We used data from Kenya HIV sentinel surveillance conducted from 1990 to 2001 among sexually transmitted disease (STD) patients (15-49 years old) to investigate consistency of gender differentials over time and their risk factors. Of the 15,889 STD patients, the HIV prevalence ranged from 16.0% in 1990 to 41.8% in 1997. The odds ratios (ORs) of HIV infection for women compared to men decreased by age; women 15-24 years were nearly twice as likely as men of the same ages to be HIV infected (OR 1.7 [1.5-2.0]), but risk in those >44 years was almost equal (OR 0.8 [95% CI 0.7-1.2]). The odds of HIV infection for women compared to men were twice in unmarried patients (OR 2.1 [95% CI 1.8-2.3]). This association persisted after controlling for age groups or marital status, residence, level of education, and presence of STD syndromes. This pattern had been consistent over 12 years. Adolescent women with symptoms of STDs should be a focus for the HIV/STD intervention programmes because of their high risk for HIV.