Domestic Waterfowl Club.

Illnesses Avain Flu

Avian Flu . . . some facts for waterfowl keepers Pics may upset some if so change the page

The type with the greatest risk is highly pathogenic avian influenza (HPAI). "Bird flu" is a phrase similar to "swine flu," "dog flu," "horse flu," or "human flu" in that it refers to an illness caused by any of many different strains of influenza viruses that have adapted to a specific host.The fear of governments is that if in the food chain it will cross species barriers and evolve  as viruses do to cause a pandemic such as Spanish Flu which killed more than both world wars and with NO remedy. Due to this every outbreak of each type = lockdown for your birds and improve biosecurity. This will happen each year so get sorted and save energy. .  the advise is keep indoors but most goose and duck keepers cannot but you can stop wild birds coming around for a snack and transmitting to your stock.

 Virus :A virus is a small infectious agent that replicates only inside the living cells of other organisms. Viruses can infect all types of life forms, from animals and plants to microorganisms, including bacteria.Viral infections in animals provoke an immune response that usually eliminates the infecting virus. Immune responses can also be produced by vaccines, which confer an artificially acquired immunity to the specific viral infection. However, some viruses including those that cause AIDS and viral hepatitis evade these immune responses and result in chronic infections. ie you live with the disease as in many wild birds with  Avian Influenza . Antibiotics have NO effect on viruses, but several antiviral drugs have been developed.These are not used at present as they give a false positive test on many birds See quote /link :-
"It is a fact that in Viet Nam, Muscovy ducks are raised in large populations (approximately 8 million), usually kept in small flocks together with mallards and chickens. As a result, it is a great concern for epidemiologists to elucidate possible differences in relation to these species being exposed to infection with H5N1. To do this, an experimental study on infections with different genotypes of H5N1 in mallards and Muscovy ducks have been conducted, where it was found that the mortality of the inoculated Muscovy ducks was at least 80%, regardless of the virus strain employed. In contrast, the mortality of the mallards ranged from nil to 100%, which suggests that Muscovy ducks are more susceptible to HPAIV H5N1 infection in terms of disease development and mortality. It was also found that higher virus titers developed in vital organs of Muscovy ducks compared to mallards, particularly in the brain. Due to their high susceptibility, it is unlikely that Muscovy ducks act as a silent reservoir. The virus strains used in this study, to a certain degree, differed in their virulence properties to the bird species in question."

*** Muscovies are almost sentinel birds ie drop dead with DVE or Avian Influenza or show symptoms before other breeds so multiple  suspicious Muscovy deaths are always a VET job. Unless you do odd things with your birds or kill them with an axe or knife as in many Asian countries you cannot catch it. . . also the bird has to be infected first**

 One of the symptoms in Muscovy due to their caruncles is that for many strains their  head will discolour like a chicken often going blue/black (Cyanosis) . They suffer from  torticollis ( twisted position + neck ) plus a swollen watery crop, ruffled feathers, dropped wings, twisted neck that follows the duckling position  shown  and after a few hours death. These symptoms together = ring DEFRA send/email pics. On this outbreak (2106/17)    of  H5 N8   research suggests that when dealing with the current viral type  Muscovy's have natural immunity to this variant. The study does look at tiny numbers but far from severe symptoms and rapid death the Muscovy's did not die and did not show any significant symptoms from infection but tey will still carry and transmit the virus . The other 3 types of poultry (hybrid layers, quail and native Korean chickens) had 100%, 100% and 60% mortality from infection.  There are also other studies which show differing pathogenicity of differing Avian Influenza viral subtypes (H5 N1, H9 N2, H7 N9) in differing poultry species.
In summary my interpretation of these results suggests that there really is no evidence of a sentinel species for Avian Influenza.  DEFRAs advice and that of the PCGBs Hon. Veterinary Surgeon is that ducks and geese are likely to be less affected by the current H5N8 viral outbreak than chickens and turkeys and the mortality rates in the confirmed outbreaks supports this, with up to 80% mortality (2000 birds) at 4 days symptomatic in the turkey farm outbreak to small numbers of wild ducks, geese and swans ( 5 max ) in reserves of thousands. Extra Info from  Dermot Gardiner

https://www.gov.uk/guidance/avian-influenza-bird-flu

You can order copies of the two biosecurity leaflets by emailor fax.

PB11393 Protect your bird from the risk of Avian flu (birdflu). Available now. This one-page leaflet is aimed at all bird owners, especially non commercial poultry keepers.

PB11380 Biosecurity and preventing disease. Available soon.This leaflet is aimed at larger commercial bird farms.

Current Regulations

A few little pointers from conversations with DEFRA:-

Birds do not have to be moved inside unless an outbreak occurs in your area but make contingency plans to do so.

DEFRA do not consider vaccination an option. Current vaccines are not effective against this strain of AI. They would only consider it if there is a world-wide epidemic and if you read the info re Muscovy above you understand why.

Waterfowl would not need to be housed if an outbreak occurred if you were able to confine them in a pen with wire sides, apertures no more than 25mm and cover the top so that no wild bird faeces can fall through. ( ie stop wild birds coming in. . . CD's on strings , whirligigs, empty air guns fired at them all work. Do NOT shoot anything but the noise or similar startling noise will work.)

History of the Disease

When avian influenza outbreaks occur in poultry, quarantine and depopulation (or culling) and surveillance around affected flocks is the preferred control and eradication option in most areas . However, it is virtually impossible to fully eliminate the virus from the environment because it can stay hidden in ducks. At an international conference in Ho Chi Minh City this week, officials said extensive research since the first major outbreak last year has confirmed that wild birds, particularly ducks, are primary reservoirs for the H5N1 virus, since they can carry it without falling ill.

Recent research findings give further cause for concern. New research suggests that H5 viruses are becoming more capable of causing disease(pathogenic) for mammals than earlier H5 viruses and are becoming more widespread in birds in the region. One study found that ducks infected with H5N1 are now shedding more virus for longer periods of time without showing any symptoms of illness. This has implications for therole of ducks in transmitting disease to other birds and possibly, to humans as well. Additionally, other findings have documented H5 infection among pigs in China and H5 infection in felines (experimental infection in housecats in the Netherlands and isolation of H5N1 viruses from infected tigers and leopards in Thailand), suggesting that cats could host or transmit the infection. These finding are particularly worrying due to the fact that reassortment of avian influenza genomes is most likely to occur when these viruses demonstrate a capacity to infect multiple species, as is now the case in Asia.

Domesticated birds may become infected with avian influenza virus through direct contact with infected waterfowl or other infected poultry, or through contact with surfaces (such as dirt or cages) or materials (such as water or feed) that have been contaminated with the virus. People, vehicles, and other inanimate objects such as cages can be responsible for the spread of influenza virus from one farm to another. When this happens, avian influenza outbreaks can occur among poultry, these outbreaks occur worldwide from time to time. Since 1997, for example, more than 16 outbreaks of H5 and H7 influenza have occurred among poultry in the United States. The H5N1 virus is easily spread from farm to farm among domestic poultry through the faeces of wild birds. The virus can survive for up to four days at 71 F (22 C) and more than 30 days at 32 F (0 C). If frozen, it can survive indefinitely so here in the UK it can transmit if imported.

. . . . . Low pathogenic forms of avian influenza viruses are responsible for most avian influenza outbreaks in poultry. Such outbreaks usually result in either no illness or mild illness (e.g., chickens producing fewer or no eggs), or low levels of mortality. When highly pathogenic influenza H5 or H7 viruses cause outbreaks, between 90% and 100% of poultry can die from infection. Animal health officials carefully monitor avian influenza outbreaks in domestic birds for several reasons:Bird flu is not the same as SARS (severe acute respiratory syndrome). Although their symptoms are similar, SARS is caused by completely different viruses. Influenza viruses also are more contagious and cannot be as readily contained as SARS by isolating people who have the infection.

Avian influenza viruses circulate among birds worldwide. Certain birds, particularly waterfowl, act as hosts for influenza viruses by carrying the virus in their intestines and shedding it. Infected birds shed virus in saliva, nasal secretions, and feces. Susceptible birds can become infected with avian influenza virus when they have contact with contaminated nasal, respiratory, or fecal material from infected birds. Fecal-to-oral transmission is the most common mode of spread between birds.Most often, the wild birds that are host to the virus do not get sick, but they can spread influenza to other birds. Infection with certain avian influenza A viruses (forexample, some H5 and H7 strains) can cause widespread disease and death among some species of domesticated birds.

Complicating the issue are traditional methods of farming in Asia that allow free-range ducks who roam from paddy to paddy to mix with chickens and other livestock.In Vietnam, for example,there are an estimated 59 million ducks, geese and other waterfowl, most raised in open-air backyard farms, according to agriculture figures.

Evidence suggests that trade in live poultry, mixing of bird species in farms and markets, and poor biosecurity in poultry production play a much bigger role than wild bird movements, Agencies"advises against the destruction of wild birds and their habitats" since it is unlikely to have a major impact on controlling the bird flu..

Countries recently  gave only about $18 million tofund an emergency response to the bird flu outbreak, which is an alarming lack of commitment. Earlier  Thailand approved a program to vaccinate free-range chickens, ducks, fighting cocks and tropical birds in a bid to ward off bird flu, reversing an earlier banon the practice.

Experts have warned that the H5N1 virus, which has ravaged the region's poultry industry and killed 45 people across Thailand, Vietnam and Cambodia, could well become even deadlier if thevirus mutates into a form that is easily transmitted between humans. So far there is no evidence of that, but health and animal experts say thelonger it remains in the environment, the greater the chances of the virus changing and triggering a global pandemic that could kill millions.

 

* Background: Influenza A (H5N1) is a subtypeof the type A influenza virus. Wild birds are the natural hosts of the virus -- hence, the name avian influenza or bird flu. The virus wasfirst isolated from birds (terns) in South Africa in 1961. The virus circulates among birds worldwide. It is very contagious among birds and can be deadly to them, particularly domesticated birds like chickens.

 

* Infection: The virus does not typicallyinfect humans. In 1997, however, the first instance of direct bird-to-human transmission of influenza A (H5N1) virus was documented during an outbreak of avian influenza among poultry in Hong Kong; the virus caused severe respiratory illness in 18 people, of whom 6 died.Since that time, there have been other instances of H5N1 infection among humans However, H5N1 viruses thus far have not been capable of efficient human-to-human transmission; health officials continue to monitor the situation closely for evidence of H5N1 transmission between people.

 

* Spread: Infected birds shed virus in saliva,nasal secretions, and feces. Avian influenza viruses spread among susceptible birds when they have contact with contaminated excretions.It is believed that most cases of H5N1 infection in humans have resulted from contact with infected poultry or contaminated surfaces.

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