Two suspected cases of swine flu have been reported in South Africa, the country's National Institute for Communicable Diseases said on Thursday.
Deputy director Lucille Blumberg said the first, which became known on Monday, was a woman from the Western Cape who travelled extensively in Mexico earlier this month.
She was in contact with people there while travelling on trains and buses.
The woman was ill with flu-like symptoms on her return to South Africa on April 24, Blumberg told a press briefing in Pretoria.
A general practitioner who treated the woman last Saturday considered swine flu as a possible diagnosis. She was given anti-viral treatment, sent home and was fine at present.
The blood sample taken from her was not stored appropriately, which meant a laboratory assessment to confirm the case could not be done.
"But she fits the case definitely," said Blumberg.
The second suspected case which the institute became aware of on Wednesday concerned a woman in Gauteng. She also returned from Mexico with a flu-like illness, but without others details made known.
"She is not particularly ill," said Blumberg.
Health department director general Thami Mseleku told journalists that there were no confirmed cases in South Africa at the moment.
"In addition, the department of agriculture has informed us there have been no cases of swine flu in pigs in South Africa or the region. The most recent case was reported in Kenya in the 1950s."
Mseleku said the risk of contracting the illness by eating pork products was very low.
"The highest risk is from imported human cases through international travel and extra vigilance is needed at ports of entry," Mseleku said.
A thermal image detection system which should aid identifying anyone possibly infected with swine flu is already in place at Lanseria airport. Getting two similar machines at OR Tambo airport up and running is being fast-tracked.
A supply of surgical masks, to cover the nose and mouth, would be available at airports. However, they would only be handed out by port health services where it is deemed necessary, according to officials.
Mseleku said the main plan was that suspected cases would be identified while on board and would then be escorted out of aircraft into isolation wards at hospitals.
Preparations to deal with any possible cases of the flu are in place in South Africa, the official declared.
All hospitals have been given guidelines on how to handle any suspected cases. South Africa will also help neighboring countries with laboratory work or case treatment, officials say.
"We are prepared for any eventuality, including treating cases." Mseleku said, adding South Africa has enough drugs available for treatment.
In any case, Blumberg said, antiviral treatment was only for people with moderate to severe symptoms. Milder cases just need lots of fluids and rest.
The flu is transmitted through human to human contact, so people should always wash their hands and put their hand in front of their face when coughing or sneezing, doctors say.
Mseleku said while travel restrictions are not being proposed, "we urge anyone who is ill not to travel either to South Africa or from South Africa."
The World Health Organization raised its flu alert on Wednesday, signaling a swine flu pandemic as "imminent" as at least nine countries had confirmed cases and another 20 countries reported suspected cases.