Tuberculosis risk among staff of a large public hospital in Kenya.

SETTING: In sub-Saharan Africa, high rates of tuberculosis (TB) and human immunodeficiency virus (HIV) infection pose a serious threat for occupationally acquired TB among health care workers. OBJECTIVE: To identify factors associated with TB disease among staff of an 1800-bed hospital in Kenya. DESIGN: We calculated TB incidence among staff and conducted a case-control study where cases (n = 65) were staff diagnosed with TB and controls (n = 316) were randomly selected staff without recent TB. RESULTS: The annual incidence of TB from 2001 to 2005 ranged from 645 to 1115 per 100000 population. Factors associated with TB disease were additional daily hours spent in rooms with patients (adjusted odds ratio [aOR] 1.3, 95%CI 1.2-1.5), working in areas where TB patients received care (aOR 2.1, 95%CI 1.1-4.2), HIV infection (aOR 29.1, 95%CI 5.1-167) and living in a slum (aOR 4.7, 95%CI 1.8-12.5) or hospital-provided low-income housing (aOR 2.6, 95%CI 1.2-5.6). CONCLUSION: Hospital exposures were associated with TB disease among staff at this hospital regardless of their job designation, even after controlling for living conditions, suggesting transmission from patients. Health care facilities should improve infection control practices, provide quality occupational health services and encourage staff testing for HIV infection to address the TB burden in hospital staff.

Aflatoxin levels in locally grown maize from Makueni District, Kenya.

OBJECTIVES: Investigations were carried out to determine aflatoxin levels in household maize in Makueni District and to correlate aflatoxin levels to maize drying and storage practices. Also, aflatoxin exposure in villages that reported aflatoxicosis cases in 2005 was compared with that in villages that did not report cases to assess whether aflatoxin exposure levels could be used to identify high-risk villages for targeted prevention interventions. DESIGN: A cross-sectional study. SETTING: Three divisions of Makueni district, Kibwezi, Makindu and Mtito Andei in Eastern Province, Kenya. SUBJECTS: Ninety six households were surveyed, and 104 maize samples were analysed for total aflatoxin levels from June to July 2005. The households were selected from high and low aflatoxicosis risk areas. RESULTS: Out of the 104 maize samples collected from 96 households, 37 (35.5%) had aflatoxin levels above the World Health Organisation (WHO) recommended maximum limit of 20 ppb. All of these samples were homegrown or purchased. Twenty one samples (20.1%) had levels above 100 ppb. Eleven (10.6%) had extremely high levels above 1000 ppb. No relief supply maize had aflatoxin levels above the WHO maximum limit. CONCLUSION: High levels of aflatoxin in homegrown and purchased maize suggested that aflatoxin exposure was widespread.

Human immunodeficiency virus (HIV) subtype surveillance of African-born persons at risk for group O and group N HIV infections in the United States.

A population-based surveillance registry was used to identify human immunodeficiency virus (HIV)-infected persons in the United States at increased risk for group O and group N infections (those born in or near African countries where group O infection has been reported). Of 155 eligible subjects, 37 gave samples. By phylogenetic and serologic analysis, 32 were infected with group M (16 with subtype A, 5 with B, 7 with C, and 1 each with subtypes D, F2, G, and recombinant A/J) and 2 with group O but none with group N virus. For 3, samples could not be typed by serology or amplified by polymerase chain reaction using group M-, O-, or N-specific primers. In the United States, group O HIV infection is uncommon; no case of group N infection was found. African-born persons may have HIV strains typical of their birth country. Ongoing subtype surveillance may allow early identification of novel or emerging HIV strains.

Emergency vaccination against epidemic meningitis in Ghana: implications for the control of meningococcal disease in West Africa.

BACKGROUND: Recurrent epidemics of meningococcal disease have been reported throughout the African meningitis belt since description of the disease in 1912. Meningooccal polysaccharide vaccines can effectively prevent disease but the optimum strategy for their use in this setting has been controversial. We used data from an outbreak of meningococcal disease in northern Ghana in 1997 to assess the potential effect of different vaccination strategies. METHODS: We identified all reported cases of meningococcal meningitis and estimated the number of cases and deaths that could have been prevented by vaccination through use of a simple mathematical model. We then assessed the potential effect of different vaccination strategies and the burden of these strategies on the public-health system. FINDINGS: In the three affected regions in northern Ghana there were 18703 cases and 1356 deaths reported between November, 1996, and May, 1997. Vaccination began in the third week of February and continued to April, reaching 72% of the at-risk population and preventing an estimated 23% of cases and 18% of deaths. A strategy of routine childhood and adult immunisation would have prevented 61% of cases had this same rate of vaccine coverage been achieved and maintained before the epidemic. If vaccination had started after the onset of the epidemic in January, as currently advocated by WHO guidelines, a similar proportion (61%) of cases could have been prevented. INTERPRETATION: Prevention of epidemics of meningococal disease in west Africa will be difficult until long-lasting conjugate vaccines capable of interrupting transmission of Neisseria meningitidis can be incorporated into routine infant-immunisation schedules. Until then, the strategy of surveillance and response advocated by WHO is as effective and more practical than a strategy of routine childhood and adult vaccination with currently available polysaccharide vaccines.

PIP: This study assessed the potential effects of different vaccination strategies using data from the 1997 meningococcal outbreak in northern Ghana. Since the description of the disease in 1912, recurrent epidemics of meningococcal disease have been reported throughout the African meningitis belt. The use of meningococcal polysaccharide vaccines has been proven to effectively prevent the disease, although the method of vaccine distribution was disputable. Using a simple mathematical model, meningococcal meningitis cases and deaths, which could have been forestalled by vaccination, were identified, and the effect of developed vaccination strategies on the public health system was analyzed. About 18,703 cases and 1356 deaths were reported in 3 regions of northern Ghana between November 1996 and May 1997. Vaccination was conducted between February and April, which covered 72% of the high-risk population and prevented approximately 23% of cases and 18% of deaths. Routine childhood and adult immunization would have prevented 61% of cases had this same rate of vaccine coverage been achieved and maintained before the epidemic. This study suggests that the prevention of the meningococcal disease epidemic in West Africa would be difficult unless long-lasting conjugate vaccines are incorporated into routine infant immunization schedules. For now, the surveillance and response strategies advocated by the WHO serve as an effective and practical intervention.