What is Henipavirus?
Henipaviruses are viruses which cause disease in birds. They are found mainly in birds such as ducks, geese, turkeys and guinea fowl. There are different types of henipaviruses. Some of them are known as “common” or “typical”. These viruses infect birds without causing any major problems to humans. Other types of henipaviruses infect only certain species of birds. For example, some viruses affect pigeons, while others affect ducks and geese. Some types of henipaviruses are very dangerous to humans. These viruses cause a condition known as “fowl plague”.
Fowl plague was first reported in the 1960s and has spread across the globe. Outbreaks of fowl plague have been reported in Asia, the Middle East, Eastern Europe and Africa.
Fowl plague is a very serious disease which can wipe out entire populations of birds. It has an impact on the economy of affected areas. The World Organisation for Animal Health has listed fowl plague as a “List A” disease, which means it has “priority” status. This means that a vaccine for fowl plague must be developed as quickly as possible.
How does it spread?
Fowl plague is spread in several different ways. The virus is spread by direct contact between infected and uninfected birds. It can also be spread by a bird-to-bird transmission of the virus, which means it can survive outside of a host. For example, the virus can be spread through an infected bird’s saliva or nasal mucus. This means the virus can survive outside of a host for up to twelve days. The virus can also survive for up to twelve days on the feathers, blood and carcasses of infected birds. It is spread by mosquitoes and other insects.
What are the signs and symptoms of fowl plague?
Clinical signs of the fowl plague in birds may include:
Reduced food intake
Swollen heads and comb
Swelling around the eyes
Lack of coordination and paralysis
Drop in egg-laying rate
Infected birds will usually die within two to four days.
How is it diagnosed?
Fowl plague is usually diagnosed by taking a history of the symptoms, and by taking a sample of blood or tissue from an infected bird. It may also be diagnosed by detecting the virus in the bird’s urine, feces, respiratory or nervous system.
How is it treated?
There is no available treatment for fowl plague.
How can it be prevented?
There are several ways to protect birds from fowl plague. Vaccinations are available against the disease. Movement restrictions and quarantines can also be used to prevent the spread of the virus. The Australian state of New South Wales has implemented a shoot-to-kill policy to prevent the spread of fowl plague. The carcasses of dead birds can also be collected and burned to prevent the spread of the disease.
Severely affected areas should be disinfected after an outbreak has occurred. It is important to clean and disinfect equipment and tools which have come into contact with infected birds.
The World Organisation for Animal Health has listed the bird flu as a “List A” disease. This is an important designation because it means there is a vaccine available to prevent the spread of the disease. Countries which have reported fowl plague in their region are encouraged to vaccinate all wild birds within a ten-kilometer radius of each outbreak.
Outbreaks of bird flu have a significant effect on the economies of affected countries. In 2005, bird flu cost India $450 million and caused the loss of over one million jobs.
In 2006, Taiwan reported an outbreak of the disease and lost over 200 million dollars in egg exports. The outbreak also cost the lives of over 200 people due to a lack of chickens and ducks available for human consumption.
What is the prognosis?
The survival rate of infected birds depends on whether or not the outbreak can be quickly contained. Vaccinations can prevent infected birds from dying, but no vaccine currently exists which can bring back an infected bird back to health.
What is the history of the disease?
The first recognized outbreak of fowl plague occurred in the Netherlands in 1878. Since then, many different strains of the virus have been identified. The first case in the United States occurred in Oregon in 1924. Since then, outbreaks of the virus have become common. In 2014, an outbreak of fowl plague occurred in Arkansas and was the largest outbreak of the virus in the United States since 1984.
In 2005, an outbreak of the disease occurred in India and Pakistan. This outbreak was particularly wide-spread and not only killed many birds, but also infected humans.
The outbreak resulted in the culling of over 22 million chickens in Pakistan and the deaths of over 70 people.
Researchers have linked the spread of fowl plague to global warming. The virus thrives in warmer temperatures and is capable of surviving in cooler temperatures for short periods of time.
As global warming increases the average temperature of the Earth, the virus is becoming more common and more widespread.
The disease also poses a significant threat to the poultry industry. Many countries rely on the meat and egg production of chickens.
In the United States, the price of eggs increases by about 40 cents per dozen whenever there is an outbreak. The loss of millions of chickens during an outbreak also results in a shortage of eggs and poultry for human consumption.
In the future, the spread of the disease could have a devastating effect on the economies of affected countries. In addition to causing significant financial losses, fowl plague also poses a serious health threat.
The virus is capable of mutating and becoming easily transmittable from human to human. The mutated forms of the virus are difficult to treat and the death rate among humans reaches close to 100%.
The increase in global temperature has also allowed avian influenza viruses to spread further into the Arctic. In the past, these sub-arctic regions were too cold for the virus to survive.
As global warming has increased the temperature of these regions, the viruses are now able to spread further north. As these viruses spread further north, they will be in a better position to spread back down into the more heavily populated regions of the globe.
How is the disease transmitted?
The virus is primarily transmitted through direct contact with infected birds. Transmission can also occur through the consumption of raw or undercooked poultry or eggs contaminated with the virus.
What are the symptoms?
The incubation period for fowl plague is 1 to 3 days. Initial symptoms include:
? Loss of Appetite
? Muscle Aches
? Respiratory Problems
As the disease progresses, the virus begins to attack the cardiovascular system. At this stage, the infected person will suffer from:
? Rapid Heartbeat
? Pale or Bluish Skin
? Shortness of Breath
? Sudden Drop in Body Temperature
If left untreated, the infected person will die within 48 hours of showing these final symptoms.
Sources & references used in this article:
- Henipavirus RNA in African bats (JF Drexler, VM Corman, F Gloza-Rausch, A Seebens… – PloS one, 2009 – journals.plos.org)
- Evidence of henipavirus infection in West African fruit bats (DTS Hayman, R Suu-Ire, AC Breed, JA McEachern… – PloS one, 2008 – journals.plos.org)
- Cedar virus: a novel Henipavirus isolated from Australian bats (GA Marsh, C De Jong, JA Barr, M Tachedjian… – PLoS …, 2012 – journals.plos.org)
- Henipavirus infection in fruit bats (Pteropus giganteus), India (JH Epstein, V Prakash, CS Smith… – Emerging infectious …, 2008 – ncbi.nlm.nih.gov)
- Outbreak of henipavirus infection, Philippines, 2014 (PKG Ching, VC de Los Reyes… – Emerging infectious …, 2015 – ncbi.nlm.nih.gov)
- Henipavirus susceptibility to environmental variables (R Fogarty, K Halpin, AD Hyatt, P Daszak, BA Mungall – Virus research, 2008 – Elsevier)