Nepal reported its first case of swine flu with three members of the same family testing positive on Monday.

The health ministry called a press conference to specify that a 48-year-old man, a 38-year-old woman and an eight-year-old boy had been found to have contracted the Influenza A(H1N1) virus.

The trio, whose identity was not revealed, has been kept in isolation, health ministry spokesman S Upreti said.

The family had reached Kathmandu's Tribhuvan International Airport on June 16 when they were diagnosed with fever. They had travelled from the US via Doha. Further tests confirmed they had contracted swine flu.

While the government stepped up vigil at its lone international airport after the outbreak of the disease in more than 100 countries, there are growing fears that the land routes are not sufficiently manned.

Nepal is connected by land route to China in the north and India. Both neighbours have reported rising incidence of the new epidemic.

This year, Nepal was also struck by bird flu (H5N1), believed to have been caused due to the smuggling of contaminated poultry from India across the open border. Thousands of birds were culled in the Jhapa district where the strain was detected, affecting poultry farmers.

However, there were no human casualties and last month, the government indicated there was no further trace of the disease.