ABUJA (AFP) - A nine-year-old American girl has become the first case of swine flu in Nigeria, Africa's most populous country, Health Minister Babatunde Osotimehin said Wednesday.

"The first case of the influenza A(H1N1), otherwise called swine flu, has been reported in Nigeria of a nine-year-old American girl residing in Lagos," Osotimehin told reporters in Abuja.

He said the girl had "presented flu-like symptom of fever, sore throat, nasal congestion and nausea" to the American consular clinic in Lagos, and she recovered fully after five days of treatment.

"Further to checks in this regard, it has been confirmed that the father, brother and all school contacts of the girl did not suffer from any flu-like symptoms and they are all well," he said

The minister said the mother of the girl had mild symptoms but had recovered fully.

"All other contacts have been tested and they have been found negative to the influenza A(H1N1)," he said.

Osotimehin urged Nigerians not to panic, adding that government would ensure adequate protection against the pandemic.

More than 5,700 people have died worldwide since the virus was first discovered in April, with most of the deaths -- 4,175 -- in the Americas region, according to the World Health Organization.