Health officials in Guinea-Bissau are struggling to contain what has become a nationwide epidemic of cholera. About 16,000 cases of the water borne disease have been recorded in the tiny West African nation, since outbreaks first appeared earlier this year.

In the main marketplace in Guinea-Bissau's capital city, Bissau, a water seller calls to potential customers as they pass in front of her stand.

The tiny former Portuguese colony is in the middle of an epidemic of cholera that has now affected all of its regions.

The disease has killed about 300 people since instances of the disease appeared in Guinea-Bissau in July. More than 4,000 new cases were reported in the past month.

Health authorities are blaming polluted wells and rivers for the spread of cholera in the countryside. In Bissau, the health ministry says raw sewage may have seeped into the public water supply through the city's cracked and aging pipes.

Nurse Mime Gomes, who is helping with efforts to educate the public on how to prevent the spread of cholera, also blames the city's water sellers.

"People should not buy this water, because the person who sells this water, she does not know the procedure to take care of water," says Ms. Gomes. "This water is not clean."

But water seller Maria Diata says the authorities are simply paranoid.

Many of the women who support their families by selling water in Bissau's main market say they are being made scapegoats by the government, which, they say, has failed to contain the outbreak.

Ms. Diata says her water is safe. She says, though she takes water from the tap and resells it, she adds lemon juice to kill any bacteria.

Health officials say this is not enough. They say all water meant for drinking must be boiled first. And people should take extra care to wash their hands with soap before eating.

Former colonial power Portugal is also helping combat the disease. It has sent tons of drugs and medical equipment and its Foreign Minister, Diogo Freitas do Amaral, says medical expertise is also being made available to Guinea-Bissau.

"We have some experience in these tropical diseases," said Mr. Amaral. "We have a very good research institute in tropical diseases in Lisbon,and we will give all the support we can."

Cases of cholera have appeared in eight West African countries this year. More than 100,000 cases of the disease, which is characterized by diarrhea and profuse vomiting, were reported last year. Most of those occurred in poor countries in the developing world.