# 6829
Not quite a month ago we learned that a `new’ clade of H5N1 had shown up in in Indonesia, causing the deaths of hundreds of thousands of ducks (see Report: Clade 2.3.2 H5N1 Detected In Indonesia) on the island of Java.
Although new to Indonesia, clade 2.3.2 has been circulating across Asia for several years. I wrote of the spread of this emerging clade in 2011 in What Goes Around, Comes Around and EID Journal: H5N1 Branching Out).
In the spring of 2010 we began to see reports of poultry vaccine failures in Vietnam due to the spread of a mutated version this clade (further classified as clade 2.3.2.1), which led to this statement FAO Warns On Bird Flu.
The H5N1 virus is constantly changing, and as it does, forms distinct genetic groups, or clades. Since its discovery in 1996, the H5N1 virus has evolved into more than 20 distinct clades (and subclades), with many variations within each.
Some of these clades have flared briefly and then died out, supplanted by more biologically `fit’ versions of the virus. But even so there is a good deal of variety among the strains in circulation today.
Clade 2.3.2 (and now 2.3.2.1) is very common in South East Asia, clades 2.2.1 and 2.2 are endemic in Egypt and up until recently, Indonesia had only dealt with clades 2.1.1, 2.1.2. and 2.1.3, but now adds 2.3.2.
Until this past week, all of the reports we’ve seen of this newly emergent clade in Indonesia have come from the island of Java.
Three days ago, Gert van der Hoek on FluTrackers posted a machine translation of a VOA Indonesia article (New Bird Flu Clade Detected in 3 districts in Bali) indicating the new clade had jumped to the vacation island of Bali.
Today, an English Language report from the Jakarta Post, Bali Edition, carries details of this latest discovery.
Bali braces for bird flu epidemic
by Muliarta on 2013-01-07
The local health authorities have begun implementing the necessary measures to deal with the ongoing outbreak of avian influenza affecting the duck population, and the possible spillover of the disease into the human population.
The measures have been taken following confirmed reports of avian influenza killing thousands of ducks in farming areas in three separate regencies: Buleleng, Tabanan and Klungkung.
Laboratory tests have confirmed that the ducks were killed by the new, more malignant strain of the avian influenza virus known as H5N1 Clade 2.3.2. A similar strain of the virus killed hundreds of thousands of ducks across farming regions in Java weeks before the first reported case in Bali.
Although the arrival of this new clade has sparked fears of more human infections, so far, we’ve not seen any sudden increase in reports of human cases in Indonesia.
Bali, a popular international tourist destination, has seen more than a half dozen high profile human H5N1 cases over the past several years.
In order to protect the island’s economy, in 2005 it was decreed that only locally raised chickens could be sold on the island.
But like many other laws and edicts concerning poultry trade in Indonesia, they have gone largely ignored. Ducks fetch a higher price on the island of Bali than on Java, providing ample incentive to smuggle poultry.
While it isn’t known whether this new strain arrived via illegal trade, or migratory birds, its arrival has nerves on edge. Bali public health officials have alerted three local hospitals to be ready to receive human cases, and a public awareness campaign is underway.
H5N1 remains largely an avian-adapted virus, and for now primarily a threat to poultry.
The concern, of course, is that with continual changes to the virus, one of these days it may better adapt to human or mammalian physiology.
Which is why, even after 10 years after its return in 2003, we continue to follow developments with keen interest.
