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In 2012, Neisseria meningitidis serogroup W caused a widespread meningitis epidemic in Burkina Faso. We describe the dynamic of the epidemic at the subdistrict level. Disease detection at this scale allows for a timelier response, which is critical in the new epidemiologic landscape created in Africa by the N. meningitidis A conjugate vaccine.

Objective: To develop a tool for evaluating the risk that an outbreak of meningitis will occur in a particular district of the Niger after outbreaks have been reported in other, specified districts of the country., Methods: A Bayesian network was represented by a graph composed of 38 nodes (one for each district in the Niger) connected by arrows. In the graph, each node directly influenced each of the "child" nodes that lay at the ends of the arrows arising from that node, according to conditional probabilities. The probabilities between "influencing" and "influenced" districts were estimated by analysis of databases that held weekly records of meningitis outbreaks in the Niger between 1986 and 2005. For each week of interest, each district was given a Boolean-variable score of 1 (if meningitis incidence in the district reached an epidemic threshold in that week) or 0., Findings: The Bayesian network approach provided important and original information, allowing the identification of the districts that influence meningitis risk in other districts (and the districts that are influenced by any particular district) and the evaluation of the level of influence between each pair of districts., Conclusion: Bayesian networks offer a promising approach to understanding the dynamics of epidemics, estimating the risk of outbreaks in particular areas and allowing control interventions to be targeted at high-risk areas.

A novel influenza A (H1N1) virus has spread rapidly across the globe. Judging its pandemic potential is difficult with limited data, but nevertheless essential to inform appropriate health responses. By analyzing the outbreak in Mexico, early data on international spread, and viral genetic diversity, we make an early assessment of transmissibility and severity. Our estimates suggest that 23,000 (range 6000 to 32,000) individuals had been infected in Mexico by late April, giving an estimated case fatality ratio (CFR) of 0.4% (range: 0.3 to 1.8%) based on confirmed and suspected deaths reported to that time. In a community outbreak in the small community of La Gloria, Veracruz, no deaths were attributed to infection, giving an upper 95% bound on CFR of 0.6%. Thus, although substantial uncertainty remains, clinical severity appears less than that seen in the 1918 influenza pandemic but comparable with that seen in the 1957 pandemic. Clinical attack rates in children in La Gloria were twice that in adults (<15 years of age: 61%; >/=15 years: 29%). Three different epidemiological analyses gave basic reproduction number (R0) estimates in the range of 1.4 to 1.6, whereas a genetic analysis gave a central estimate of 1.2. This range of values is consistent with 14 to 73 generations of human-to-human transmission having occurred in Mexico to late April. Transmissibility is therefore substantially higher than that of seasonal flu, and comparable with lower estimates of R0 obtained from previous influenza pandemics.

Adults more than 40 years old are not necessarily immune to measles. A measles outbreak that involved healthcare workers occurred after contact with a 44-year-old patient. Results of a hospital-wide program of mass screening revealed that 117 (4.5%) of 2,600 individuals tested seronegative for measles; 31 (26.1%) of these 117 individuals were more than 40 years old.

Postoperative endophthalmitis is a rare but potentially devastating condition. We investigated an outbreak of 8 cases of endophthalmitis in patients who underwent phakectomy performed by a single surgeon from January through September 2004. The outbreak was traced to damaged surgical blades, and it highlights the importance of the quality of the surgical wound.

Background: Risk factors influencing the incidence of human immunodeficiency virus (HIV) infection were investigated in a case-control study nested within a community-randomized trial of treatment of syndromic sexually transmitted infections (STIs) in rural Tanzania., Methods: Case patients were persons who became HIV positive, and control subjects were randomly selected from among persons who remained HIV negative. For each sex, we obtained adjusted odds ratios (ORs) and population-attributable fractions (PAFs) for biomedical and behavioral factors., Results: We analyzed 92 case patients and 903 control subjects. In both sexes, the incidence of HIV infection was significantly higher in subjects with an HIV-positive spouse than in those with HIV-negative spouse (men: OR, 25.1; women: OR, 34.0). The incidence of HIV infection was significantly higher in those who became positive for herpes simplex virus type 2 (HSV-2) (men: OR, 5.60; women: OR, 4.76) and those who were HSV-2-positive at baseline (men: OR, 3.66; women: OR, 2.88) than in subjects who were HSV-2 negative. In women, living elsewhere (OR, 3.22) and never having given birth (OR, 4.27) were significant risk factors. After adjustment, the incidence of HIV infection was not significantly associated with a history of injections or STIs in either sex., Conclusion: HSV-2 infection was the most important risk factor for HIV infection, which highlights the need for HSV-2 interventions in HIV infection control, and there were particularly strong associations with recent HSV-2 seroconversion. The PAF associated with having an HIV-positive spouse was low, but this is likely to increase during the epidemic.