Health providers and aid groups have mobilized to combat outbreaks of cholera in Haiti and Nigeria. Often causing extreme dysentery and dehydration, cholera arises from a strain of bacteria that is easily spread and hard to eradicate from infected zones. Cholera is a common after-effect of natural calamities.

Ever since January's massive earthquake devastated Haiti, health officials have warned of the dangers of cholera. In a country where public sanitation infrastructure is poor to non-existent and clean drinking water is often hard to come by, more than 3,000 cholera cases and more than 250 deaths have been reported in recent weeks, mostly north of Port-au-Prince.

Doctor John Andrus, Deputy Director of the Pan American Health Organization in Washington, spoke with reporters this week:

"People with low immunity, such as malnourished children or people with the HIV virus, are of greatest risk for death, if infected [with cholera]," said Andrus.

Across the Atlantic, heavy rains are blamed for more than 1,500 cholera deaths in Nigeria so far this year, including the brother of this man.

He said that he was at the house of his brother, who was feeling ill. He says he gave his brother salt water and took him to a hospital the next day. Two days later, the man says, his brother was dead.

The past year has also seen cholera outbreaks in Zimbabwe, Pakistan, India, and Bangladesh.

Cholera often emerges in underdeveloped regions struck by disaster, according to infectious disease expert Peter Hotez of George Washington University.

"It is a disease that occurs under extreme conditions: with individuals who are debilitated because of malnutrition, but also where there is a massive breakdown of public health infrastructure - either because of war in a refugee camp setting, or in extreme poverty, or in settings of natural disasters such as earthquakes and floods," said Hotez.

Cholera is easily treatable with saline solutions, intravenous fluids, and antibiotics - but time is of the essence. Absent swift medical attention, death can come in a matter of hours, according to Dr. Hotez.

"The cholera bacillus produces a toxin, and this toxin has the ability to poison cells in such a way that you can no longer absorb water from your gastro-intestinal tract," he said. "In fact, you start secreting massive volumes of water. So you can become a shriveled, desiccated individual just a few hours after infection."

Not everyone who contracts cholera falls ill. Some show no symptoms but nonetheless can spread bacteria in the surrounding environment. Water purification, hand-washing, and proper waste disposal are recommended to prevent and contain cholera.

Haiti's cholera outbreak is its first in decades. Health experts say the epidemic already shows signs of ebbing and will likely continue to do so. But they add that Haiti and its island-neighbor, the Dominican Republic, could see new cases for years to come.

Again, Dr. John Andrus of the Pan American Health Organization:

"Now that cholera has established itself with a strong foothold in Haiti, it is clear to us that this will not go away for several years," he said.

In the short term, health officials and aid groups can rush treatments and supplies to cholera-stricken regions. In the long term, improving sanitation and overall infrastructure in underdeveloped regions is seen as key to combating the disease.

debilitated: 疲惫不堪的；衰弱

saline: a mixture of salt in water（盐水）

bacillus: a type of bacteria. There are several types of bacillus, some of which cause disease. 杆菌（有些可致病）

desiccated: 脱水的

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（来源：VOA 编辑：陈丹妮）