Some of the cases of influenza A H1N1, commonly known as swine flu, were linked to community transmission, spokeswoman Nombuso Shabalala said in a statement.

Fourteen of these cases were of people who travelled to countries with community transmission.

Some students who were members of a squash team that recently played at the University of Johannesburg, who lived in the same residence, and their contacts accounted for 16 cases.

Shabalala said the majority of the students had mild illness and were all recovering.

"It is highly likely that further cases linked to this event or contact with these confirmed known cases will occur in many parts of South Africa as they return to their home towns.

"It is also highly likely that there are additional cases linked to this event with very mild disease, who are undiagnosed."

Shabalala also ruled out the possibility of containing swine flu, given the highly infectious nature of the virus. Many cases with mild symptoms would go undiagnosed. People could spread infection a day before symptoms developed.

She also warned that focus should be directed at identifying people who were at risk of complications, particularly those with moderate or severe illness and close contacts who may be at risk for complications.

"Persons at risk for complications include the elderly and anyone with chronic underlying illness, such as diabetes, immuno deficiency, diabetes, and chronic chest problems."

She said although the institute continued providing testing for travellers returning from countries with swine flu, the situation needed to be monitored in South Africa given concerns around infections in people with compromised immune systems.

Sapa

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