Explaining the difference between bacterial and viral infections is a persistent problem, but there's now evidence that the two might not be quite as separate as once thought. A clinical trial involving more than 37 000 children has shown that use of the pneumococcal vaccine prevented 31% of pneumonias associated with any of seven respiratory viruses—raising the possibility that infant pneumococcal immunization might reduce morbidity and deaths linked to influenza and other viral pneumonias in children and adults (Nature Medicine 2004;doi:10.1038/nm1077).

Erectile dysfunction has a strong and independent association with silent cardiac ischemia in people with apparently uncomplicated type 2 diabetes (Circulation 2004;110: 22-6). The implications are two-fold. First, erectile dysfunction might become a useful marker to identify diabetic patients at risk of silent ischemia. Second, it might be sensible to perform an exercise electrocardiogram before starting treatment for erectile dysfunction, especially in people with other cardiovascular risk factors.

Though Minerva rarely manages to squash mosquitoes, she derives great satisfaction when she does. But US doctors say it's better to flick mosquitoes off skin, rather than squashing them, after a 57 year old woman died from …