A Gozitan teenager was the latest person to contract swine flu, bringing the number of infected cases to 19.
It is still to be determined whether this is the first locally-transmitted case of swine flu.
Asked whether the young woman had been abroad, a spokesman for the Community Care Parliamentary Secretariat said contact tracing was still being carried out in the evening.
If this is indeed the first non-imported case, it means the virus has started spreading among people on the island. But the general director for health, Ray Busuttil said that, even if this were the first case of secondary transmission in Malta, one case would not bring about big changes. However, it would make it even more important for people who are ill to stay at home and away from others, he said.
"We are trying to delay as much as possible secondary infection and the widespread onset of disease," he said.
The worldwide predictions for swine flu are that it will affect 18 per cent of populations with five per cent of those affected needing hospitalisation. The mortality rate has been worked at 0.2 per cent, similar to the death rate for the seasonal influenza.
Until Friday, almost 90,000 cases of swine flu were confirmed around the world, with 382 people falling victim to the disease. The highest number of deaths was registered in the US, followed by Mexico, where the disease started earlier this year.
The good news for the elderly is that they seem to have a greater immunity to swine flu with young adults being the most affected by the swine flu. In fact, the majority of cases in Malta so far have been people in their 20s. The reason why the elderly have a greater immunity to swine flu could lie in the fact that they were exposed to influenza strains with the H1 and N1 subtypes in the past.
Last month, Keiji Fukuda, from the World Health Organisation, said young adults seemed to be more prone to succumb to swine flu.
The first case of swine flu in Malta was confirmed on Wednesday evening in two rugby players who had just returned from a trip to Spain. Two of their team mates tested positive the next day as the tally continued rising among holidaymakers and those arriving from abroad.
The first person to be admitted to hospital was an 18-month-old British boy who was holidaying with his family in Gozo. However, he was discharged on Saturday after starting treatment with Tamiflu. An 18-year-old British woman who was diagnosed with swine flu on Saturday was admitted to hospital for observation. She is still being treated in hospital although her condition has improved.
Prime Minister Lawrence Gonzi said yesterday the country was well prepared for the pandemic, with stocks of medication and precautions in place. He said he expected the numbers of infected people to go up. Dr Gonzi said the new wing at St Vincent de Paul Residence for the elderly could be used to contain those who fell ill with the virus.