Tuesday, October 04, 2005

Indonesia's "poultry link"

AP (via Jakarta Post) reports that Indonesian investigators have established a link between the country's six (confirmed) H5N1 fatalities and poultry living near their homes.
"We can't be sure how the victims were infected by poultry around their house, but there is definitely a link," [Agriculture Minister Anton Apriyantono] told reporters.
Maybe. I'd like to see the evidence. Poultry are ubiquitous in Indonesia, so the chances are that almost anyone would be living "near" some poultry. We don't know what "near" means nor do we know if a comparison has been made between proximity of the cases and proximity of a sample of non-cases from the same population that gave rise to the cases. This latter requirement is a bit tricky as you don't want to "over match" controls from the same neighborhood as this would automatically fail to show a relationship. A random sample from Jakarta might be more appropriate.

Even if a link is established (i.e., cases are on average closer to poultry than non-cases), the question of what "near" means is critical. Visitors to the zoo who later fell ill were also "near" infected birds but the exposure was almost incidental and signals an efficiency of transmission qualitatively different than seen hitherto.

Thus this "reassuring" report implying transmission is not human-to-human is not very informative.