21.   Researchers say the virus almost certainly infected humans repeatedly as they killed and ate chimpanzees over the years, but that it is hard to start an AIDS epidemic.

22.   Several forms of TSE infect humans.

23.   She finally found she had Lyme disease, a bacteriological malady that can infect humans through the bite of a tick.

24.   Six viruses that infect humans have been strongly linked to cancers, Dr. Nancy Mueller of the Harvard School of Public Health said in opening the meeting.

25.   Since baboons carry viruses that might infect humans, there is a potential risk that the baboon marrow transplant could transmit a devastating new disease to humans.

26.   Some scientists worry that increased use of antibiotics to treat the udder infections will promote antibiotic resistance in bacteria that can infect humans.

27.   Strong action is needed because many germs that infect humans are growing resistant to treatment with antibiotics.

28.   The archea do not infect humans, making them safer to manipulate.

29.   The most dangerous of these obscure conditions have made the mysterious leap from animals to infect humans, mainly in tropical climates far from the United States.

30.   The North Dakota man had cutaneous, not inhalational, anthrax, meaning the infection began in his skin, the most common way the bacteria infect humans.