Friday, April 04, 2008

WHO | Avian influenza – situation in Pakistan - update 2

The two best kept secrets in Pakistan

The first secret is, 'Where is Osama bin Laden?'. Secret number two is that there was confirmed Human-to-Human (H2H) spread of Avain flu in Pakistan more than 5 months ago. Here's the complete info release from the WHO:

WHO | Avian influenza – situation in Pakistan - update 2

3 April 2008

Two additional H5N1 cases were confirmed by serological testing, thus providing final H5N1 infection test results on a previously reported family cluster in Peshawar.

These tests were conducted by the WHO H5 Reference Laboratory in Cairo, Egypt and the WHO Collaborating Centre for Reference and Research on Influenza in Atlanta, USA. The table below summarises the testing results of the confirmed/probable cases in the family cluster.

  • The preliminary risk assessment found no evidence of sustained or community human to human transmission.
  • All identified close contacts including the other members of the affected family and involved health care workers remain asymptomatic and have been removed from close medical observation.

These laboratory test results support the epidemiological findings from the outbreak investigation in December 2007, and the final risk assessment that suggested limited human to human transmission likely occurred among some of the family members which is consistent with some human-to-human transmission events reported previously. This outbreak did not extend into the community, and appropriate steps were taken to reduce future risks of human infections.

Relationship Onset Date Outcome Exposure Status
Case 1 (Index case) 29 Oct 07 Fully recovered Direct contact sick/dead poultry Confirmed (serology)
Case 2 12 Nov 07 Dead (19 Nov 07) Close contact with Case 1, no known direct contact with sick/dead poultry Probable
(No sample available)
Case 3 21 Nov 07 Dead (28 Nov 07) Close contact with Case 1 and 2, no known direct contact with sick/dead poultry Confirmed (PCR)
Case 4 21 Nov 07 Fully recovered Close contact with Case 1 and 2, no known direct contact with sick/dead poultry Confirmed (serology)

It is great news that the H2H transmission burned out before it hit the wider community. But many aspects of this news are troubling. First and foremost is the credibility of the WHO reporting. It seems that we hear complete details if a single duck shows up with H5N1 in Eureka-stan; why such a delay for major news such as H2H?

Speaking of credibility, contrast today's news with this Reuters article on December 28, 2007:

No proof of human-to-human bird flu in Pakistan No evidence that bird flu passed between relatives, WHO says

Reutersupdated 1:10 p.m. ET, Fri., Dec. 28, 2007

GENEVA -The World Health Organization said on Thursday it had established a single case of human infection of the H5N1 bird flu virus in a sick family in Pakistan but there was no apparent risk of it spreading further.

A statement from the U.N. agency said tests in its special laboratories in Cairo and London had established the “human infection” through presence of the virus “collected from one case in an affected family.”

But it said a WHO team invited to Pakistan to look into an outbreak involving up to nine people from late October to December 6 had found no evidence of sustained or community human-to-human transmission.

No identified close contacts of the people infected, including health workers and other members of the affected family, had shown any symptoms and they had all been removed from medical observation, the WHO added.

The outbreak followed a culling of infected chickens in the Peshawar region, in which a veterinary doctor was involved. Subsequently he and three of his brothers developed proven or suspected pneumonia.

The brothers cared for one another and had close personal contact both at home and in hospital, a WHO spokesman in Geneva said. One of them, who was not involved in the culling, died on November 23, but the cause of death was not known.

On November 28 another brother who had not been involved in the culling died, and tests on him — in Pakistan as well as in Cairo and London — had established the presence of the H5N1 virus.

(snip)

The WHO spokesman told Reuters on Thursday all the evidence ”suggests that the outbreak within this family does not pose a broader risk. He added: “But there is already heightened surveillance and there is a need for ongoing vigilance.”

Truth delayed, is none the less the truth. But going forward it is harder to accept what the WHO says is the truth.

2 comments:

Dipl.-Ing. Wilfried Soddemann said...

Spread of avian flu by drinking water can explain small clusters in households

Proved awareness to ecology and transmission is necessary to understand the spread of avian flu. For this it is insufficient exclusive to test samples from wild birds, poultry and humans for avian flu viruses. Samples from the known abiotic vehicles also have to be analysed. There are plain links between the cold, rainy seasons as well as floods and the spread of avian flu. That is just why abiotic vehicles have to be analysed. The direct biotic transmission from birds, poultry or humans to humans can not depend on the cold, rainy seasons or floods. Water is a very efficient abiotic vehicle for the spread of viruses - in particular of fecal as well as by mouth, nose and eyes excreted viruses.
Infected birds and poultry can everywhere contaminate the drinking water. All humans have very intensive contact to drinking water. To prove viruses in water is difficult because of dilution. If you find no viruses you can not be sure that there are not any. On the other hand in water viruses remain viable for a long time. Water has to be tested for influenza viruses by cell culture and in particular by the more sensitive molecular biology method PCR.
There is a widespread link between avian flu and water, e.g. in Egypt to the Nile delta or Indonesia to residential districts of less prosperous humans with backyard flocks and without central water supply as in Vietnam:
http://www.cdc.gov/ncidod/EID/vol12no12/06-0829.htm.
See also the WHO web side:
http://www.who.int/water_sanitation_health/emerging/h5n1background.pdf and
http://www.umg-verlag.de/umwelt-medizin-gesellschaft/407_m_s.html
“Influenza: Initial introduction of influenza viruses to the population via abiotic water supply versus biotic human viral respirated droplet shedding” and
http://www.thelancet.com/journals/laninf/article/PIIS1473309907700294/abstract?iseop=true
“Transmission of influenza A in human beings”.
Avian flu infections may increase in consequence to increase of virus circulation. Transmission of avian flu by direct contact to infected poultry is an unproved assumption from the WHO. There is no evidence that influenza primarily is transmitted by saliva droplets.
In hot climates/the tropics flood-related influenza is typical after extreme weather and floods. Virulence of influenza viruses depends on temperature and time. Special in cases of local water supplies with “young” and fresh H5N1 contaminated water from low local wells, cisterns, tanks, rain barrels, ponds, rivers or rice paddies this pathway can explain small clusters in households. At 24°C e.g. in the tropics the virulence of influenza viruses in water amount to 2 days.
Human to human and contact transmission of influenza occur - but are overvalued immense. In the course of influenza epidemics in Germany, recognized clusters are rare, accounting for just 9 percent of cases e.g. in the 2005 season.
In temperate climates for “older” water from central water supplies cold water is decisive to virulence of viruses. At 7°C the virulence of influenza viruses in water amount to 14 days. In temperate climates the lethal H5N1 virus will be transferred to humans via cold drinking water, as with the birds in February and March 2006, strong seasonal at the time when drinking water has its temperature minimum.
The performance to eliminate viruses from the drinking water processing plants regularly does not meet the requirements of the WHO and the USA/USEPA. Conventional disinfection procedures are poor, because microorganisms in the water are not in suspension, but embedded in particles. Even ground water used for drinking water is not free from viruses.

Dipl.-Ing. Wilfried Soddemann - Free Science Journalist - soddemann-aachen@t-online.de

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