Proof and disproof

The human bird flu cases in Indonesia continue to be worrisome. The virus there seems to move more easily now from birds to humans, since recent cases (and the zoo associated cases) haven't had heavy contact with infected birds, although in most of the cases some history of dead or dying birds in the vicinity has been reported.

The two most recent women who died, however, fall into the category of those with no known contact with flu-infected birds, reminiscent of the first cases of the government civil servant (an auditor) and his child who started the Indonesian outbreak in July.

"It remains unclear how the two people contracted the disease,'' said Ilham Patu, 47, a medical officer with Sulianti Saroso, one of two hospitals in Jakarta designated to treat bird-flu cases.

A government investigation found no fowl or other birds were infected with the bird-flu virus near their homes, Patu said in an interview today.

[snip]

In about 80 percent of human cases, the infection was probably caused by direct contact with sick or dying birds, Georg Petersen, WHO's representative in Jakarta, said in a Nov. 14 interview.

"Then we are left with a group of people where we don't know exactly how they got infected,'' Petersen said. In cases where more than one person in a family became infected, authorities may ``know the source of one person, but not the others,'' he said.

Human-to-human transmission of the H5N1 avian flu virus is "not proven and not disproved,'' Petersen said. "There is only one case published from Thailand'' where human-to-human transmission is implicated, he said.

In Indonesia, two teenagers who had developed symptoms are undergoing tests for the virus. Neither had been exposed to H5N1-infected chickens at their homes, Patu said. (Bloomberg)

So there you have it. Human-to-human is neither proven nor disproved. On the other hand, if there are dead birds in the vicinity, this seems to demonstrate it isn't human-to-human. Which makes me wonder, what will proof consist of? A large cluster?

Just asking.