Some 60,000 people have been infected, but the country's Health Ministry is resisting pressure to declare an emergency despite a U.N. warning that the disease is an epidemic.
"The fact that it is spreading to new areas in the country is cause for serious concern," said Paul Hebert, head of the U.N.'s Office for the Coordination of Humanitarian Affairs in Ethiopia. "The full extent of this needs to be addressed."
The U.N. has not officially declared the outbreak, which began nearly a year ago, to be cholera. But U.N. officials speaking privately because of the sensitivity of the issue are saying it is cholera, something local officials continue to deny.
Eight of Ethiopia's 11 regions have already been affected by the outbreak, according to Ethiopia's Health Ministry and the U.N. The remote eastern region of Afar has recorded more than 1,000 new cases in the last week alone.
The outbreak started in April 2006 after heavy rains in the country. Neighboring Somalia and Kenya have also been hit, and more than 1,000 people have been infected with suspected cholera in Uganda's capital since October. In Kenya, 17 people have died since October.
"Once a disease has been present for an extended period of time, then the likelihood of it being eliminated is quite difficult," Hebert said.
"I don't think we are addressing this issue on the scale that is needed and it needs to be targeted to have an impact."
Ethiopian health officials, who say the disease is not cholera, are describing the outbreak as acute watery diarrhea, but they have not shared any of the test results that they have carried out.
Ethiopian Health Ministry spokesman Ahmed Emano said that contrary to U.N. concerns, the outbreak was being contained by the government.
Cholera is transmitted through contaminated water and is linked to poor hygiene, overcrowding and bad sanitation. Symptoms include diarrhea and vomiting and it is deadly if untreated. "It can kill someone in as little as five hours," said Kebba O. Jaiteh, emergency officer with the U.N.'s World Health Organization in Ethiopia.
Ethiopia's economy could suffer if the country declares a cholera emergency.
"The Ethiopian Health Ministry did not share the results of the lab tests since last April," Jaiteh said. "It can mean some serious economic losses, especially in terms of international trade and tourism.
"Many African countries don't declare a cholera emergency even when they know for a fact that it is in their country for these very economic reasons."
The U.N. in Ethiopia has said the disease is suspected of having entered Ethiopia from Sudan last year, where the disease was confirmed in early 2006.
U.N. officials in Ethiopia are unable to act on their own about the issue and are obligated to follow the lead of the country's Ministry of Health.
Only after a disease has been recorded as active in an area for one year can the WHO declare an emergency and label the disease as endemic to the country.
Fears are mounting that with the onset of next month's rainy season the outbreak could worsen.
"The rainy season is coming soon so it might get worse if we do not do something soon," said Dr. Patrick Mweki, head of the International Medical Corps in Somalia.
Government health officials say the situation in Uganda is now under control. "Now that the rains have disappeared, the cholera has really subsided, said Dr. Sam Okware, the commissioner for public health services at Uganda's Health Ministry.