Dead Swans: Avian Flu Strain the Cause
In the adjoining English county - a mere 40 miles or so from where I type this, I learn that three swans have been found dead.
The cause of death? Avian flu. (The H5N1 strain)
The dead birds were found at Abbotsbury swannery in Dorset which is a colony of mute swans. The swannery dates back to the 11th century and was established by Benedicitine monks.
Staff discovered the deaths during a routine check and are now being administered Tamiflu tablets as a precaution.
Whether it is more of a shock when it happens to such beautiful creatures is of course debatable, yet certainly it seems to have upset the people I have spoken to more than usual.
And as a report in The Guardian states:
The outbreak comes less than a month after restrictions on poultry movement were lifted in Norfolk and Suffolk that had been imposed after an outbreak of H5N1 on a free range turkey farm in November.
This is not good timing at all.
It is thought that wild birds are the source of the infection.
But certainly, as far as this writer is concerned, avian influenza still seems a rather mysterious area. It pops up in the news far too often, yet still I am ignorant as to the facts. So here goes.
Recent UK History
Again referring to the Guardian piece it states that in 2005 a parrot died of the disease. Fortunately the bird was in quarantine at the time which allowed the UK to maintain its disease-free status.
In April, 2006, 35,000 chickens had to be slaughtered at a farm in the south of England after an outbreak of the disease was discovered.
12 months ago, 159,000 turkeys had to be culled - again in the south of England - after it was found that some of the birds had died suspiciously. It appears the H5N1 strain was to blame.
Two months ago, yet again in the same part of the country, 5,000 birds were destroyed at a poultry farm during another outbreak.
What is Avian Flu?
The disease came to light in Italy around 100 years ago. It can affect a variety of both domesticated and wild birds.
This site explains:
Infection can range from asymptomatic to severe, depending on the virulence of the virus and the susceptibility of the avian host. Avian influenza in domestic chickens and turkeys is classified according to disease severity, with two recognized forms: highly pathogenic avian influenza (HPAI), also known as fowl plague, and low-pathogenic avian influenza (LPAI).
Avian influenza viruses that cause HPAI are highly virulent and mortality rates in infected flocks often approach 100%. While LPAI viruses are generally of lower virulence, LPAI in flocks should be controlled because LPAI viruses can serve as progenitors to HPAI viruses.
Sources:
The Guardian incl. Q and A
Center for Infectious Disease Research and Policy
Picture obtained here.
Pretty scary stuff, but wonderfully written. Interesting to hear from someone so close to the scene.
Very much so. The mass culls in the south of England have all occurred within the same two counties as far as I am aware.
Certainly, it raises questions over farming techniques, though of course the problem is far more complicated than just that.
But broadly speaking, you put thousands of poultry together within a confined space, you’re going to have health problems, avian flu or otherwise.
Definitely. This makes sense and it reminds me of other, similar medical troubles that farmers have when they try to raise too many animals in a small enclosure.
Not too long ago, I read Jane Goodall’s Harvest For Hope, which included some information about this. But it seems like the avian flu is a little more of a going concern (at least for our species) than, say, sea lice in overcrowded salmon farms.
H5N1 avian flu: Spread by drinking water
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 webside: http://www.who.int/water_sanitation_health/emerging/h5n1background.pdf and http://www.umwelt-medizin-gesellschaft.de/ abstract in English “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. Infected poultry can everywhere contaminate the drinking water. All humans have contact to drinking water. Special in cases of decentral water supplies this pathway can explain small cluster in households. In hot climates and the tropics flood-related influenza is typical after extreme weather and natural after floods. The virulence of the influenza virus depends on temperature and time. If young and fresh H5N1 contaminated water from low local wells, cisterns, tanks, rain barrels or rice fields is used for water supply the water temperature for infection may be higher (at 24°C the virulence of influenza viruses amount to 2 days) as 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 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 cluster are rare, accounting for just 9 percent of cases 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.
In temperate climates strong seasonal waterborne infections like the norovirus, rotavirus, salmonella, campylobacter and - differing from the usual dogma - influenza are mainly triggered by drinking water, dependent on the water’s temperature (in Germany it is at a minimum in February and March and at a maximum in August). There is no evidence that influenza primarily is transmitted by saliva droplets. In temperate climates the strong interdependence between influenza infections and environmental temperatures can’t be explained by the primary biotic transmission by saliva droplets from human to human at temperatures of 37.5°C. There must be an abiotic vehicle like cold drinking water. There is no other appropriate abiotic vehicle. In Germany about 98 percent of inhabitants have a central public water supply with older and better protected water. Therefore, in Germany cold water is decisive to the virulence of viruses.
Dipl.-Ing. Wilfried Soddemann - Free Science Journalist - soddemann-aachen@t-online.de - http://www.dugi-ev.de/information.html - Epidemiological Analysis: http://www.dugi-ev.de/TW_INFEKTIONEN_H5N1_20071019.pdf
Influenza virus continuously changes through small changes in their makeup called antigenic drift and sometimes abrupt changes called antigenic drift.
This means that even though you may have fought and won a battle against the flu miserable a year or two earlier, the next time the virus appears your body will not recognize it because your body antibodies against Influenza has made the last time will not work. That’s why people need to be vaccinated against influenza every year, using the most up-to-date strains of the virus.
There are three types of influenza viruses: A, B and C. Type C causes only mild problems in humans. Type B can cause a more serious illness and seasonal epidemics, but because it does not change through the slow process of antigenic drift there is little risk of a pandemic, where millions of people are suddenly exposed to a new, radically different virus.
This threat is more likely to come from type A, which can undergo rapid change.