We investigated an unusually large and severe outbreak of hepatitis B, primarily involving parenteral drug abusers and their sexual contacts, in Worcester, Massachusetts, over a 21-month period from 1983 to 1985. Of 135 patients with drug-related acute hepatitis B, 81 percent were parenteral drug abusers and 19 percent had sexual contact with drug abusers; 13 fulminant cases resulted in 11 deaths. Among the patients with hepatitis B, evidence of delta virus infection was found in 54 percent of drug abusers, 33 percent of their sexual contacts, and 9 percent of other patients with acute hepatitis B (P less than 0.001). Most of the delta infections (86 percent) were coinfections with hepatitis B virus; the balance were superinfections. Delta infection was strongly associated with fulminant hepatitis: 91 percent of patients with a fulminant outcome had delta infection, as compared with 45 percent of less severely ill drug abusers and their contacts (P = 0.0037). Alcohol, other drugs, and other hepatitis viruses could not be implicated as hepatotoxic cofactors for fulminant disease. This outbreak appeared to result from the concurrent spread of hepatitis B and delta viruses among new drug users. Control measures included the distribution to physicians of guidelines on prophylaxis in contacts of patients with hepatitis B, health education for drug abusers, and a hepatitis B vaccination program. Despite these efforts, the outbreak continued unabated until the number of new cases began to decline slowly in late 1986.

As a rule, both the standard of hygiene and sanitation prevalent in hospitals in the United States and the rarity of parasitic diseases compared to viral, bacterial, and fungal infections, reduce the hazard of nosocomial acquisition of parasites to relatively trivial levels. However, abetted by the resultant low index of suspicion on the part of clinical staff, certain parasitic microorganisms may at times cause significant morbidity and even mortality in both normal and immunocompromised patients, as summarized in this review. Also, the nosocomial acquisition of parasites may be somewhat underappreciated because the incubation period for clinical illness may be days to weeks and thus a hospital-acquired infection may not be recognized as such, particularly if the parasite is endemic locally. Parasitic diseases have been a much more significant problem in certain special facilities, such as custodial institutions for the mentally ill or retarded, where crowding, poor environmental sanitation, and low levels of personal hygiene have in the past allowed the rapid dissemination and endemic occurrence of a large variety of parasitic infections. It is likely that nosocomial transmission of parasites may be an even greater problem in some hospitals in the tropics, where strict hygienic standards are costly or otherwise more difficult to maintain, and where often an increased proportion of the patient population harbors one or more parasites. However, the exact magnitude of the problem in tropical hospitals is also more difficult to determine because nosocomial acquisition of a parasitic infection may not be distinguished easily versus exogenous infection or reactivation of latent infection.(ABSTRACT TRUNCATED AT 250 WORDS)

A previously asymptomatic carrier of hepatitis B virus receiving chronic hemodialysis developed acute delta hepatitis. The patient regularly received dialysis treatments on the same machine as a parenteral drug abuser with hepatitis B surface antigen (HBsAg)-positive chronic hepatitis whose serum was strongly positive for delta antibody. The drug abuser had a major bleeding episode that caused extensive environmental contamination 3 months before onset of illness in the index patient. No other patients receiving dialysis or staff members had evidence of delta infection. A surgeon previously infected with hepatitis B from the same parenteral drug abuser also had delta antibody. Testing for delta virus is indicated for both HBsAg-positive parenteral drug abusers and patients with hemophilia receiving chronic hemodialysis. All patients who are HBsAg- and delta-positive should receive dialysis separately from patients who are HBsAg-positive and delta-negative. Susceptible patients on dialysis and staff should receive hepatitis B vaccine to protect against both hepatitis B and delta virus infection.

As a rule, both the standard of hygiene and sanitation prevalent in hospitals in the United States and the rarity of parasitic diseases compared to viral, bacterial, and fungal infections, reduce the hazard of nosocomial acquisition of parasites to relatively trivial levels. However, abetted by the resultant low index of suspicion on the part of clinical staff, certain parasitic microorganisms may at times cause significant morbidity and even mortality in both normal and immunocompromised patients, as summarized in this review. Also, the nosocomial acquisition of parasites may be somewhat underappreciated because the incubation period for clinical illness may be days to weeks and thus a hospital-acquired infection may not be recognized as such, particularly if the parasite is endemic locally. Parasitic diseases have been a much more significant problem in certain special facilities, such as custodial institutions for the mentally ill or retarded, where crowding, poor environmental sanitation, and low levels of personal hygiene have in the past allowed the rapid dissemination and endemic occurrence of a large variety of parasitic infections. It is likely that nosocomial transmission of parasites may be an even greater problem in some hospitals in the tropics, where strict hygienic standards are costly or otherwise more difficult to maintain, and where often an increased proportion of the patient population harbors one or more parasites. However, the exact magnitude of the problem in tropical hospitals is also more difficult to determine because nosocomial acquisition of a parasitic infection may not be distinguished easily versus exogenous infection or reactivation of latent infection.(ABSTRACT TRUNCATED AT 250 WORDS)

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