AN EPIDEMIC OF PNEUMOCOCCAL DISEASE IN AN OVERCROWDED, INADEQUATELY VENTILATED JAIL

Background. In the United States many correctional facilities now oper ate at far over capacity, with the potential for living conditions tha t permit outbreaks of respiratory infections. We investigated an outbr eak that was identified in an overcrowded Houston jail after two inmat es died of pneumococcal sepsis on the same day. Outbreaks of pneumococ cal disease have been rare in the era of antibiotics. Methods. We asse ssed risk factors for pneumococcal disease in both a case-control and a cohort study. Ventilation was evaluated by measuring carbon dioxide levels and air flow to the living areas of the jail. The extent of asy mptomatic infection was determined by culturing pharyngeal specimens f rom a random sample of inmates. Type-specific immunity was determined with an enzyme immunoassay. Results. Over a four-week period, 46 inmat es had either acute pneumonia or invasive pneumococcal disease due to Streptococcus pneumoniae serotype 12F. The jail's capacity had been se t at 3500 inmates, but it housed 6700 at the time of the outbreak; the inmates had a median living area of only 34 ft(2) (3.2 m(2)) (interqu artile range, 28 to 56 ft(2) [2.6 to 5.2 m(2)]) per person. There were significantly fewer cases of disease among inmates with 80 ft(2) (7.4 m(2)) per person or more (P = 0.030). Carbon dioxide levels ranged fr om 1100 to 2500 ppm (acceptable, <1000), and the ventilation system de livered a median of only 6.1 ft(3) of outside air per minute per perso n (interquartile range, 4.4 to 8.5 ft(3); recommended, greater than or equal to 20 ft(3)). The attack rate was highest among inmates in cell s with the highest carbon dioxide levels and the lowest volume of outs ide air delivered by the ventilation system (relative risk, 1.94; 95 p ercent confidence interval, 1.08 to 3.48). Of underlying medical condi tions, intravenous drug use was most strongly associated with disease (odds ratio, 4.50). The epidemic strain (serotype 12F) was cultured fr om 7 percent of the asymptomatic inmates. Of 11 case patients tested w ith the enzyme immunoassay, 9 (82 percent) lacked preexisting immunity to this strain. Conclusions. Severe overcrowding, inadequate ventilat ion, and altered host susceptibility all contributed to this outbreak of pneumococcal disease in a large urban jail.