# 1861
After having been declared `bird flu free' last summer, the H5N1 virus has returned to South Korea with a vengeance this spring. In a little over a week there have been reports of outbreaks in as many as 25 locations.
This from the Yonhap News Agency.
Bird flu spreading through southwestern S. Korea
SEOUL, April 11 (Yonhap) -- Bird flu outbreaks that started killing chickens and ducks in late March have spread through the southwestern part of South Korea despite intensified quarantine efforts, the government said Friday.
The Ministry for Food, Agriculture, Forestry and Fisheries said suspected outbreaks of avian influenza have been discovered in Naju, about 355 kilometers south of Seoul.
It was the second discovery in the region after authorities found suspected cases in Yeongam, 25 kilometers south of Naju, earlier in the week.
The ministry said three duck farms in Naju may have been hit by bird flu, and that more detailed tests are needed to ascertain the exact cause and to confirm if a virulent strain is the cause of the deaths.
The first outbreaks occurred in areas about 100 kilometers north of Naju, with several confirmed and suspected cases in Gimje and Jeongeup.
The ministry said there are now 25 confirmed and suspected cases of bird flu, with officials scrambling to cull and bury birds to prevent further contamination.
"As a precautionary measure, all birds within a 10 kilometer radius of Gimje and Jeongeup farms are to be destroyed," a quarantine official said. He added similar steps are to be taken for ducks and chickens within 3 kilometers of Yeongam.
He said the decision will result in over 2.36 million birds being culled in these regions. The animal expert, however, said that concerns of another outbreak in Sunchang, 364 kilometers south of Seoul, arose from other causes.
South Korean health authorities, meanwhile, said a person who reported having symptoms similar to bird flu during the week tested negative.
The Korea Center for Disease Control and Prevention said the person who had taken samples for analysis from areas of bird flu outbreaks is already feeling better and has been released from observation. It said polymerase chain reaction tests carried out Thursday showed he was suffering from human flu and not a mutated form of the virus that has caused human deaths in the past.
Posts
1 comments:
Spread of avian flu by drinking water:
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 .
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.
http://www.un.org/apps/news/story.asp?NewsID=26096&Cr=&Cr1
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.
Dipl.-Ing. Wilfried Soddemann - Free Science Journalist - soddemann-aachen@t-online.de
Post a Comment