Spread of avian flu by drinking water.

I got an article as  comments in my previous post Bangladesh reports first human case of H5N1 bird flu by Dipl.-Ing. Wilfried Soddemann – Epidemiologist – Free Science Journalist. I found it is interesting so publishing it as a post in my blog.

I want to thank Mr. Wilfried Soddemann for his excellent comments. Here is the article-

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

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: “Transmission of influenza A in human beings” http://www.thelancet.com/journals/laninf/article/PIIS1473309907700294/abstract?iseop=true .

Avian flu infections may increase in consequence to increase of virus circulation. 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. 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.

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 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.

Ducks and rice [paddies = flooded by water] major factors in bird flu outbreaks, says UN agency
Ducks and rice fields may be a critical factor in spreading H5N1
26 March 2008 – Ducks, rice [fields, paddies = flooded by water! Farmers on work drink the water from rice paddies!] and people – and not chickens – have emerged as the most significant factors in the spread of avian influenza in Thailand and Viet Nam, according to a study carried out by a group of experts from the United Nations Food and Agriculture Organization (FAO) and associated research centres.

“Mapping H5N1 highly pathogenic avian influenza risk in Southeast Asia: ducks, rice and people” also finds that these factors are probably behind persistent outbreaks in other countries such as Cambodia and Laos.
The study, which examined a series of waves of H5N1 highly pathogenic avian influenza in Thailand and Viet Nam between early 2004 and late 2005, was initiated and coordinated by FAO senior veterinary officer Jan Slingenbergh and just published in the latest issue of the Proceedings of the National Academy of Sciences of the United States.
Through the use of satellite mapping, researchers looked at a number of different factors, including the numbers of ducks, geese and chickens, human population size, rice cultivation and geography, and found a strong link between duck grazing patterns and rice cropping intensity.

In Thailand, for example, the proportion of young ducks in flocks was found to peak in September-October; these rapidly growing young ducks can therefore benefit from the peak of the rice harvest in November-December [at the beginning of the cold: Thailand, Viet Nam, Cambodia, Laos are situated – different from Indonesia – in the northern hemisphere].

“These peaks in congregation of ducks indicate periods in which there is an increase in the chances for virus release and exposure, and rice paddies often become a temporary habitat for wild bird species,” the agency said in a news release.

“We now know much better where and when to expect H5N1 flare-ups, and this helps to target prevention and control,” said Mr. Slingenbergh. “In addition, with virus persistence becoming increasingly confined to areas with intensive rice-duck agriculture in eastern and south-eastern Asia, evolution of the H5N1 virus may become easier to predict.”

He said the findings can help better target control efforts and replace indiscriminate mass vaccination.
FAO estimates that approximately 90 per cent of the world’s more than 1 billion domestic ducks are in Asia, with about 75 per cent of that in China and Viet Nam. Thailand has about 11 million ducks.

Bangladesh reports first human case of H5N1 bird flu.

Authorities here have stepped up surveillance against avian influenza after the case of a 16-month-old boy, who took ill in January, was diagnosed as one of infection with the deadly H5N1 virus.

Bangladesh become the 15th country to report a case of human infection after the Geneva-based World Health Organisation (WHO), citing results from laboratories at the Centres for Disease Control (CDC) in Atlanta, confirmed the infection on Thursday.

Since 2003, when bird flu first surfaced, 15 countries have reported a total of 382 human cases, with 241 of them turning fatal. WHO has now confirmed human cases in Azerbaijan, Cambodia, China, Djibouti, Egypt, Indonesia, Iraq, Laos, Burma, Nigeria, Pakistan, Thailand, Turkey, Vietnam and Bangladesh.

Prof. Mahmudur Rahman, a director at Bangladesh’s Institute of Epidemiology, Disease Control and Research (IEDCR), told IPS that although the boy was totally cured well before the confirmation, surveillance has been stepped up across the country.

Since the H5N1 virus was first detected in Bangladesh, at a state-run poultry farm on the outskirts of the capital, authorities have culled more than two million birds, causing losses estimated at 700 million US dollars.

With 47 of Bangladesh’s 64 districts affected, the poultry industry, introduced two decades ago to help this impoverished country, is now facing its biggest ever challenge. Affected are more than 1.5 million people employed in one of the world’s largest poultry industries that produces producing 220 million chickens and 37 million ducks annually.

According to the South Asia Enterprise Development Facility, a multi-donor facility managed by the International Finance Corporation of the World Bank Group, the poultry sector supports five million people directly or indirectly through 150,000 poultry farms, constituting 1.6 percent of Bangladesh’s gross domestic product (GDP).

In recent years, the poultry industry has been growing at an annual rate of about 20 percent, recording a turnover of 25 -1.5 billion dollars in 2006. Analysts say the figures for 2007 may fall below that mark thanks to drastic culling.

Battered by the culling, monsoon floods and a devastating cyclone in November, the country’s once booming poultry industry is now seriously threatened. Businessmen say the outbreak has already caused the closure of more than a third of the country’s poultry farms.

As the virus spread, the state-owned Bangladesh TV and a dozen or so private cable TV channels often broadcast programmes on avian influenza making people aware of the deadly virus, but observers said impact is minimal.

‘’Street vendors are still selling live chickens in Dhaka, although the city corporation authority has imposed a ban on selling live chickens in the open,’’ said Dhaka school teacher Sharif Ahmed.

Without disclosing the identity of the affected boy, Rahman said he lived in a crowded slum in Dhaka. His parents had bought a live chicken from a nearby market which they kept in their house for some days before slaughtering it for a meal.

The boy was among the more than 3,000 people suspected of being infected with bird flu in Bangladesh, but his was the only case that tested positive, a health department official said.

After the Bangladesh government was informed of the test results by the WHO, the national advisory committee on avian influenza met on Thursday to step up measures.

Rahman said IEDCR was already conducting surveillance measures in the districts affected by bird flu and that people who were in direct contact with poultry birds and products were being kept under observation by epidemiologists. As part of the new measures, Bangladesh will set up isolation units in all public hospitals, he said.

“Right now everything is under control. We have trained doctors and readied hospitals to tackle any new detection,” Rahman said. ‘’We also have trained volunteers in the villages.’’

Bangladesh, which has a population of nearly 150 million, is the world’s most densely populated country with nearly 1,000 people per sq km. With poultry farms set up everywhere in the country the risk of the virus spreading fast is high.

Earlier this year, India’s West Bengal state which shares a long border with Bangladesh suffered the neighbouring country’s worst outbreak of the virus among poultry. But no human cases of bird flu have been reported in India, which has also carried out massive poultry culling.

Bird flu was thought only to infect birds until the first human cases were detected in Hong Kong in 1997. Though rare, humans catch the disease through close contact with infected birds.

Experts consider vigilance and speedy action such as isolation of human cases important because of a fear that the H5N1 strain could mutate to become capable of human-to-human transmission and set off a deadly pandemic. Densely populated countries like Bangladesh, where people live in close proximity to backyard poultry or keep birds in their homes, are seen as particularly risky.

Part-2: Bird Flu.

I found this on the BBC Website. I think it will be help you to know more about bird flu. So publishing it to my blog.

The Original Link is in- BBC News

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Part-1: Bird Flu.

There’s been a lot of talk about bird flu.

Bird (avian) flu is an influenza virus type A that normally infects birds, but can also infect pigs and other animals. Wild birds, the natural hosts, normally don’t get sick from this virus, but domestic animals such as chickens and turkeys can be severely affected severely. Humans, meanwhile, can be infected with influenza types A, B, and C.

Genetic changes and sharing (the closest thing viruses have to sex) can occur under certain circumstances such as in crowded conditions where poultry, pigs, and people live in close quarters. This change can allow a virus to become much more infectious to humans and more easily transmitted from person to person. And this is where a “pandemic” comes in: it’s a worldwide outbreak of a new influenza A virus between humans, while epidemics tend to be seasonal, involving viruses that already exist.

Symptoms of bird flu

  • Fever
  • Sore throat
  • Muscle aches
  • Headache
  • Lethargy
  • Conjunctivitis (eye infections)
  • Breathing problems
  • Chest pains

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