In distant days we suffered great plagues, influenza outbreaks that killed millions worldwide and other mass diseases. So how is it that, for example, the periodic outbreaks of plague ever stopped? It wasn't the Great Fire of London every time ( A favourite explanation for the ending of the plague of 1665, given to generations of British children, was 'it was stopped by the Great Fire of 1666' )And why did the outbreaks of influenza,such as that which killed so many about the time of the Great War, stop? It certainly wasn't the work of doctors ending these attacks, given the ignorance in past days. Yet these pandemics stopped almost as suddenly as they began.
They never really end - in fact AIDs is considered pandemic as it extends beyond the boundaries of a continent. As for "the plague", it still exists although now is considered endemic meaning that it has a low to moderate incidence rate in a population.
"Today Plague is endemic in various places; Madagascar, Tanzania, Brazil, Peru, Burma, and Vietnam have experienced cases almost every year since the start of the last pandemic in 1880, and rodents in the southwestern United States carry it! In fact, 40% of the U.S land area is infested by Plague-infected animals, mostly prairie dogs! Some national parks have signs saying not to feed the squirrels because they have Plague.
Since 1947, there have been 390 cases of Plague in the U.S. resulting in 60 deaths. From 1980-1994 this country has had 229 cases with 33 deaths. The last two Americans to succumb to Plague died in August 1996, both due to transmission by way of prairie dogs. A thirteen year-old Kazakhstani boy died of bubonic Plague on August 9, 1999—the first such death in that country in 25 years. Many other nonfatal cases have been reported" Source
Certainly there has been a decline in epidemics. This is attributed to vaccinations (or course) and in earlier days, improved sanitary habits and a better standard of living. For present day, the CDC has comprised a group called "Epidemic Intelligence Service" and part of their duties is to find the root cause of major epidemics and eradicate.
Posts: 9192 | Location: Atlanta, GA, USA | Registered: 06-03-02
That's fine for nowadays Georgia; naturally there are pockets of a disease around; but what puzzles was how and why the diseases went into remission in past centuries. There seems no obvious reason why plague or influenza was killing millions one week but weeks later was not. There can't be a shortage of victims simply because the disease has killed so many that there's not enough left to carry it further, can there? Does it mutate and become less virulent or are there some other causes at work?
I have been doing some reading about this and there is some evidence that in some cases there were persons with the genetic ability to block the Disease from even infecting the body.
The first known possibility of this genetic resistant quailty of the Plague was in the small, central-England village of Eyam.
quote:
In September 1665, George Viccars, a tailor in the small, central-England village of Eyam, received a parcel of cloth ridden with plague-infected fleas from London. Four days later, Viccars died. By the end of the month, five more villagers had succumbed to the plague. The panicked town turned to their rector, William Mompesson, who persuaded them to quarantine the entire village to prevent the bacterium from spreading throughout the region. It seemed like suicide. A year later, the first outsiders ventured into Eyam, expecting a ghost town. Yet, miraculously, half the town had survived. How did so many villagers live through the most devastating disease known to man?
So, researchers began to determine, if they could, what common genetic feature the survivors of the Plague shared.
quote:
Knowing who died and who lived through the early years of the plague is somewhat problematic. Deaths among the general English population were not recorded in the 14th Century -- the height of the Plague -- and most communities did not begin recording parish registers until around 1538. Fortunately, Eyam began keeping a parish register in 1630. Thus historian John Clifford began by examining the register, noting everyone who was alive in 1665, the year the plague came to Eyam. He searched for evidence of life through the year 1725 -- marriages, baptisms, burials that took place years after the plague had left the village. Deleting the names of those lost during the plague period, he was able to determine who the survivors were.
After all was said and done, Dr. Stephen O'Brien felt that the mutated CCR5 gene, delta 32, may have prevented the plague from being able to enter its host's white blood cells.
quote:
After three weeks of testing at University College in London, delta 32 had been found in 14% of the samples.
In fact, incredibly, this mechanism seems to be the same mechanism that current persons who are HIV resistant possess naturally!
And it was discovered (cross-referenced) quite by accident!
quote:
Virologist Dr. Bill Paxton at the Aaron Diamond AIDS Research Center in New York City noticed, "the center had no study of people who were exposed to HIV but who had remained negative." He began testing the blood of high-risk, HIV-negative individuals like Steve Crohn, exposing their blood to three thousand times the amount of HIV normally needed to infect a cell. Steve's blood never became infected. "We thought maybe we had infected the culture with bacteria or whatever," says Paxton. "So we went back to Steve. But it was the same result. We went back again and again. Same result." Paxton began studying Crohn's DNA, and concluded there was some sort of blocking mechanism preventing the virus from binding to his cells. Further research showed that that mechanism was delta 32.
At any rate, you should read the whole article, it is absolutely fascinating (at least to me ).
( A favourite explanation for the ending of the plague of 1665, given to generations of British children, was 'it was stopped by the Great Fire of 1666' )And why did the outbreaks of influenza,such as that which killed so many about the time of the Great War, stop? It certainly wasn't the work of doctors ending these attacks, given the ignorance in past days. Yet these pandemics stopped almost as suddenly as they began.
