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Animal link to human health


The link between animal viruses and human health is under the spotlight. Diseases like SARS, HIV and Avian flu probably originated in animals and evolved to humans. A new flu pandemic, which many experts believe is inevitable, combined with an animal virus could have a devastating impact across the world.

Scientific experts at a British Royal Society [1] conference in London in January 2004 said there was a growing risk that more viruses will jump the species barrier and infect humans.

Influenza viruses are classified as types A, B and C.

Type A flu viruses are found in many species of animals, including ducks, chickens, pigs, whales, horses, and seals. According to the World Health Organisation the avian flu outbreak in Asia which has resulted in 20 deaths in Thailand and Vietnam are from Type A subgroup H5N1. National officials have slaughtered hundreds of thousands of chickens in an effort to stop the disease from spreading. In China, thousands of civet cats have been killed after researchers found links between the animal and new cases of SARS.

In 2003, EU veterinary experts restricted the movement of poultry and eggs from Belgium and the Netherlands throughout the Union and beyond. This followed an outbreak of avian flu in the Netherlands of the virus strand A H7N7 . A total of 30 million birds were culled, 89 cases of human related avian flu were recorded and one death. In this instance there was evidence of transmission to humans, but the main symptoms were conjunctivitis rather than more serious health problems.

The EU is to act by fast-tracking the legislation needed to create the European Centre for Disease Control (ECDC) through the Parliament and the Council, and better information exchange between Member States.

On 13 February 2004, the former Commissioner for Health, David Byrne, announced a new planning instrument, a working paper on Influenza Pandemic Preparedness and Response Planning in the Community. It will explain the stages of an influenza pandemic based on WHO definitions and set out the main objectives for action. The paper will address key issues of co-ordination and the availability of vaccines and anti-virals.

- More information on Europa Server.

- EPHA’s section on communicable diseases

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Footnotes

[1] The Royal Society is the independent scientific academy of the UK dedicated to promoting excellence in science.

Last modified on May 30 2005.

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15 January 2004 09:40, by Joe HART

Avian Flu Outbreak in the EU

Only 2 types of Highly Pathogenic Avian Influenza (HPAI) strains have ever been known to infect humans. However there is no cross-protection between the 15 different known hemagglutinin subtypes of influenza A virus, so specific subtype vaccines are necessary to gain protection.

The 2 subtypes of the influenza A virus known as (H7N7), (H5N1) have been associated with HPAI and (H9N2) are those potentially posing a major risk to humans because of their virulence in avian species and the intensity of symptoms in humans.

Current 2003/04 vaccines are using H3N2 & H1N1 serotypes. Following last years Dutch outbreak caused by H7N7, and the new Vietnamese outbreak by H5N1, some general questions need to be raised:

- Are adequate press briefings being made (I have seen media articles which ignore the H7N7 serotype in humans)

- is vaccination of humans a viable economic option for workers at risk in the poultry industry or for visitors intending travelling to tropical regions of Asia?

- does the recent Hong Kong outbreak caused by H9N2 avian strain (milder in avian species but with severe symptoms in children) also merit its inclusion in a vaccine cocktail?

- Have these strains been reported resistant to rimantadine / Amantadine hydrochloride ?

While resistance to neuraminidase inhibitors zanamivir and oseltamivir has not been seen in human clinical practice, they have relatively high incidence of side effects. Are there any other effective antiviral alternatives against HPAI infections for humans?

See online : Extensive explanations of different types of flu

23 January 2004 08:37, by J. Hart Consulting

> Animal link to human health

WHO has stated that the simultaneous occurrence in several countries of large epidemics of highly pathogenic H5N1 influenza in domestic poultry is historically unprecedented. The present situation may grow worse. In bird populations, the disease is highly contagious and rapidly fatal, and spreads easily from farm to farm. Wild migratory waterfowl can spread infection to domestic flocks. The potential for further spread of ongoing poultry epidemics, both within affected countries and to other countries, is therefore great. Furthermore due to the ability of this serotype to propagate in wild and domestic pig populations concern in the pig meat industry is to be expected. http://www.who.int/entity/csr/don/2004_01_23/en

In addition to the Thailand outbreak confirmed today http://www.who.int/entity/csr/don/2004_01_22/en as being H5N1, the report below also cites outbreaks in Korea and Japan. While there was no mention of the H7N7 & H9N2 serotypes in these reports focusing on H5N1, in view of the similar problems in vaccine production due the high mortality for avian species, see http://www.who.int/csr/don/2004_01_20/en/ concern for vaccine availability is a real issue. Lead times are relatively short with candidate vaccines being produced using reverse genetic techniques thus these can be made available within a matter of months. However these need to be fully tested prior to mass production.

See online : Korea & japan H5N1 outbreaks

28 January 2004 09:21, by J Hart Consulting

> Animal link to human health

Recommendation that people at risk i.e. in contact with pig , poultry & pig /poultry products have a human flu vaccination.

This will minimize the risks that the avian flu virus will be able to evolve (recombine) to pick up genes allowing it to become more infectious for humans with a possibility to transfer between humans.