The results of our investigation suggested that the hospital cooling towers were the source of a community outbreak of LD. Increasing proximity to and frequency of exposure to the towers increased the risk of LD. New guidelines for cooling tower maintenance are needed. Knowing the location of cooling towers could facilitate maintenance inspections and outbreak investigations.

A total of 80 human infections by Escherichia coli O157:H7 were documented in Finland in 1997 and 1998. Most were sporadic and their sources undetermined. Five cases not associated with one another, one of which led to secondary transmission within a family, could be traced to five different dairy farms. These five case patients (age range 2-17 years, median age 3 years) were hospitalised with bloody diarrhoea; two of them developed haemolytic uraemic syndrome. All nine human isolates obtained were sorbitol negative, carried the verocytotoxin 2 and eae genes, and produced verocytotoxin and enterohaemolysin. The phage and pulsed-field gel electrophoresis types of the human and bovine isolates from the corresponding farms were indistinguishable. The cattle (20-70 animals per farm) were monitored for up to 2 years after the human cases. The proportion of cattle excreting the type that caused the human infections varied from 3.2 to 66.7% when sampled soon after the human cases, and from 0.0 to 5.3% about a year or so later. On most of the farms, the animals excreted the pathogen intermittently. On one farm, Escherichia coli O157 isolates with other characteristics were also occasionally isolated. Although the infections were traced back to the farms, it could not be established whether the source was unpasteurised milk or direct or indirect contact with cattle. The results of this study emphasise the need for special recommendations for children visiting or living on a farm to prevent these infections.

Puumala hantavirus infection is prevalent throughout most of Europe, and in endemic areas it may be the most common cause of acute renal failure. To evaluate trends in incidence of Puumala virus infections in Finland, we analysed national surveillance data in 12-month periods from March 1995 to February 2002. During this time, 8184 laboratory-confirmed cases were notified to the National Infectious Disease Register. Three epidemic periods were identified, for which the number of cases was more than 1400 (there were approximately 600-900 cases per non-epidemic period). The incidence of Puumala hantavirus infection varied by geographic region during the study period, and the overall number of cases may be increasing.

Pneumococcal disease, which includes pneumococcal pneumonia, meningitis, and bacteremia, is associated with substantial morbidity, mortality, and health care costs in adults. Advanced age, chronic lung or cardiovascular disease, immunosuppressive conditions, and smoking increase the risk for infection. Despite the availability of an effective pneumococcal polysaccharide vaccine (PPSV23), vaccination rates among adults remain suboptimal. This is of immediate concern given the current H1N1 pandemic, since secondary bacterial infection with Streptococcus pneumoniae is common and can contribute to morbidity and mortality. The Centers for Disease Control and Prevention has recently called for increased efforts to vaccinate recommended persons against pneumococcal disease. Long-term trends including the growth of the elderly population and an increase in the number of patients with chronic conditions also underscore the importance of improving pneumococcal vaccination rates. It is important for health care providers, public health officials, and policy makers to recognize the serious health impact of pneumococcal disease in adults and to ensure increased coverage; at present, this is the best way to protect against invasive pneumococcal infection and its consequences.

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