H5N1 Transmission in Cikelet Patients in Garut Cluster
Recombinomics Commentary
August 22, 2006
Deaths from respiratory illness are known to have occurred in late July and early August, but no samples were taken and medical records are generally poor. Though some of these undiagnosed deaths occurred in family members of confirmed cases, the investigation has found no evidence of human-to-human transmission and no evidence that the virus is spreading more easily from birds to humans.
The cooperation of residents is good, house-to-house surveillance for febrile illness is continuing, and specimens have been taken from symptomatic persons and sent for testing. The team is well-supplied with antiviral drugs, and these are being administered prophylactically to close contacts of cases and therapeutically to persons showing symptoms of influenza-like illness.
The above comments from the latest WHO update may be factually correct, but misleading. The undiagnosed deaths of family members were initially cited as typhus. However, the fatalities had bird flu symptoms, and there is little doubt that they died of H5N1 bird flu. Two fatalities are cousins of a confirmed case. One of the siblings (20M), who died August 6 was initially described as a likely case. His sister (14F) died August 1, and may have been the index case for the region. Her brother and cousin were described early in WHO updates. They both developed symptoms on July 26, but the disease onset date for the sister has not been released. A third sibling has been hospitalized, but released. Similarly, the cousin was released, even though he was H5N1 positive. This familial clusters developed symptoms over an extended time frame, consistent with human-to-human transmission. A fourth sibling has symptoms also, but was not hospitalized.
Similarly, the daughter (9F) of another confirmed cases died 3-14 days prior to her mother’s (35F) death, which is developed symptoms on August 8, as described in the WHO update.
Tamiflu is being dispensed to hundreds, if not thousands, of residents in the associated villages, consistent with the Tamiflu blanket response described previously. These treatments may generate false negatives.
The number of confirmed and suspect cases in the small region around Cikelet, indicates the transmission to humans is more efficient than has been seen previously.
The report of bird flu in the region in June, coupled with the collection of birds for feeding to dogs, raises the possibility that the H5N1 in the region has acquired additional mammalian polymorphisms via recombination, and is therefore more adapted to infections in humans. In the Jakarta area, almost all human isolates have a novel cleavage site which has not been reported in bird isolates, raising the possibility of a mammalian reservoir. Media reports indicated the sequences from the current cluster do not match Karo or Bekasi, suggesting a third sub-clade of Indonesian H5N1 is circulating.
More information on these sequences would be useful.
Media Sources
Phylogenetic Trees