Tuesday, December 8, 2009

Flu or Flew?

Everyone you talk to, complain about someone who fell a victim of Dengue fever.
My wife suffered from it last year.
Mosquitoes are there nad Malaria is there.
I heard of this new fever when in Delhi.
The scourge has spread all over India.
In this context I bring to you an article I read on the diseases.

We humans might think we're pretty clever because we invented digital watches, colour TV, poetry, and income tax. But as far as viruses and bacteria are concerned, we're just meat.


Over the last 20 years we've seen a few diseases, such as AIDS, pop up from virtually nowhere. And now we're finding more and more diseases that jump from one species to another.

Sometimes, these diseases spill over from domestic animals to wildlife populations. In Australia, a disease called Sarcoptic mange 2 has jumped from dogs to wombats.

Sometimes the disease can jump from one animal to another, and even make it extinct. This happened with the wild dogs in the Serengeti in 1991. Domestic dogs in the area had a canine distemper, which hopped across to the wild dogs, and wiped them out completely.

Sometimes, the disease can spread to many different species. In August 1999, a range of creatures in New York and nearby Long Island were struck with a very strange and unusual viral encephalitis (an inflammation of the brain).

By the time it was all over, the encephalitis had killed several thousand wild crows, nine of the 23 horses that had been infected, and seven of the 60 people who had caught the disease.

After a lot of hard scientific work, the villain was found to be the West Nile Virus. It's carried by mosquitoes. It's well known to cause encephalitis in humans and horses in the Middle East, Africa, and parts of Europe, but this was its first entry into America.

Sometimes, the disease is just a new version of an old disease. In early 1998, there was a very unusual outbreak of influenza A (H5N1) in Hong Kong. H5N1 was known, but had previously infected only birds such as poultry. This was the first time that it had attacked people.

Very quickly, six of the 18 people who were infected died.

The government officials acted with brutal efficiency, and slaughtered all of the millions of poultry birds in Hong Kong.

We'll never know for sure, but many infectious disease scientists say that this quick action stopped the spread of what could have been another killer influenza epidemic.


The last big influenza epidemic — called the Spanish Flu — occurred just after World War I, and killed over 20 million people worldwide. So H5N1 might have been a repeat offender.

But sometimes the disease comes from domesticated animals, and is previously unknown. This happened in late 1994, in the town of Hendra, in southeast Queensland.

Some horses in a stable run by a Mr Vic Rail became very ill. Fourteen of these horses had very high fevers of 41°C. They soon died of lung disease, with frothy blood coming out of their noses.

Both Vic Rail and his stablehand got this disease. The stablehand recovered, but Vic Rail died. The virus turned out to be a paramyxovirus, which had successfully jumped from horses to humans.

The area was quickly quarantined, causing severe disruption to the Queensland horse industry. But thanks to the quarantine, there was very little impact interstate, and the Melbourne Cup was able to go ahead, and stop the nation.

But there could have been a bigger cost. The very first case of this disease was in a mare that had come from Cannon Hill. There's an export meat works in the Cannon Hill area.

Luckily, the paramyxovirus, now called the Hendra virus, did not cause damage to Australia's export meat markets.

But diseases do cost money.

In New Hampshire in 1994, 665 people had to be treated because of a single kitten with rabies in a pet store. That cost $1.1 million.

In Australia, there was a recent infection of pilchards, which left us with dead fish scattered across our southern coasts. That cost the Australian fishing industry $12 million over three years.

Back in the USA, the cost of introduced diseases to the health of crops and livestock, and to humans, is about $41 billion every year.

Sometimes the cost of these viruses or bacteria moving into previously unexposed populations is not measured in dollars, but in human grief.

In the 15th and 16th centuries, the Spanish Conquistadors bought smallpox, typhus and measles into South America, and 50 million native South Americans died.

Diseases have been with us for millions of years, and there is no easy solution.

There are a few things we can do about it. Domesticated dogs that live near the Serengeti National Park are now vaccinated against rabies. This seems to be stopping rabies in wild dogs.

In a similar way, mountain gorillas in Africa are being vaccinated against measles, while chimpanzees are being vaccinated against polio virus.

But we'll need to look harder at known viruses and bacteria, and look even harder for unknown ones in the environment.

We need to involve many different types of scientists and medical specialists from different fields to work out what is making these diseases spread, so that we can stamp them out.

Because if we don't, the Doomsday Bug might stamp on us.

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