Kubu Simbelang, Indonesia ? The biggest case yet of humans infecting others with bird flu prompted the World Health Organization to put the maker of the anti-viral drug Tamiflu on alert for possible shipment of the global stockpile for the first time, officials said Saturday.

No further action on the emergency supply was expected for now, according to the U.N. health agency, which called the alert part of its standard operating procedure when a case arises like that in Indonesia. “We have no intention of shipping that stockpile,” WHO spokesman Dick Thompson cautioned. “We see this as a practice run.”

Meanwhile, Indonesia confirmed three more bird flu deaths as the country grapples with a spike in human cases. Bird flu is known to have infected 48 people in Indonesia, with 36 deaths – second highest after Vietnam’s 42 deaths.

A precautionary 9,500 treatment doses of Tamiflu from a separate WHO stockpile, along with protective gear, were flown into Indonesia on Friday. The tablets will likely be handed over to the Indonesian government, WHO spokeswoman Maria Cheng said in Geneva.

Officials revealed the stockpile alert came last Monday as experts puzzled over why six Indonesians from a family in a North Sumatra village died after being infected by the H5N1 virus. A seventh was buried before tests could be done, but she is believed to have been infected.

Despite the cluster of deaths, the virus has not mutated into a form easily passed among humans, experts said. Scientists have seen examples of bird flu passing between family members in a handful of smaller cases.

“If this virus had evolved into a form that is more easily passed between people, you would have seen some other cases (outside the family) by now,” Cheng said. “The virus hasn’t passed beyond the family.”

No health workers could be seen Saturday in the family’s village of Kubu Simbelang, where dozens of chickens ran among houses and through backyards framed by high mountains and surrounded by rich fields of chilis, oranges and limes.

The family infected by the virus lived in three houses near the church in the Christian village.

Indonesia’s number of human bird flu cases has jumped this year, but public awareness of the disease remains low and government efforts have not equaled that of other countries. Indonesia’s reaction has raised concerns it is moving slowly and ineffectively in containing the disease.

Vietnam, the country hit hardest by bird flu, has been hailed for controlling the virus through mass poultry vaccination, among other measures. No human cases have been reported there since November.