21.   All of the men apparently caught the virus by giving oral sex, rather than receiving it, and none used condoms.

22.   But the U.S.-based site operator insists he caught the virus in time.

23.   Even if treatment began only at birth, this reduced the chance of catching the virus by two-thirds.

24.   He joked that the fact that he caught the virus in Moscow showed that he was still in contact with the people.

25.   Health chiefs said the finding indicated that people could be at risk of catching the virus by visiting poultry markets.

26.   However, it is possible to catch a virus from a document or program attached to an e-mail message.

27.   It is also possible to catch a virus if you set your software package to read attach documents or run attached programs without checking them first.

28.   It is not possible to catch a virus from just reading an e-mail message.

29.   Meanwhile, it emerged yesterday that people had been put off signing up for clinical trials on the bird flu vaccine because of fears they may catch the virus.

30.   Neither the man infected earlier this month, nor a Swiss research scientist who caught the virus last year, died.