segunda-feira, 25 de outubro de 2010

Cholera outbreak confirmed in Haiti, fatalities mounting

Emerging Diseases
Posted October 22, 2010

Cholera outbreak confirmed in Haiti, fatalities mounting

VANCOUVER — Haitian President, Rene Preval confirmed that there have been at least 138 fatalities from more than 1,500 cases in an outbreak of cholera in the central region of the country. In a press conference at the 48th Annual Meeting of the Infectious Diseases Society of America, Pan American Health Organization Deputy Director, Jon Andrus said that the case-fatality ratio is approximately 9%.
"These are preliminary figures and we expect them to change," Andrus said. "The reported cases and deaths have come primarily from areas where there was no direct damage from the earthquake, but where there are vulnerable populations living in impoverished situations."
It is currently unknown whether cholera is occurring in the temporary settlements housing individuals displaced by the Jan. 12, 2010 earthquake, according to Andrus.
Immediate response
Andrus said that the Pan American Health Organization is collaborating with a number of organizations, including the Cuban Medical Mission, Medecins Sans Frontieres, Minustha, the Office for the Coordination of Humanitarian Affairs and UNICEF. Participating organizations from North America include USAID, the US State Department, the US CDC, NIH and FDA; contributing Canadian organizations are Health Canada, the Public Health Agency of Canada and the Canadian International Development Agency.
The Haitian Ministry of Health is working with international collaborators to provide medicines and supplies from the PROMESS warehouse near the Port-au-Prince airport, according to Andrus. He said that the warehouse has 750,000 packets of oral rehydration salts - which are enough to treat 100,000 cases of moderate diarrhea - and enough IV fluids to treat 4,000 cases of severe diarrhea. There are also 300,000 courses of antibiotics available for use.
Herbert L. DuPont, MD, an Infectious Disease News Editorial Board member, said that the key challenge is getting treatment to individuals who are difficult to reach. "The problem is that you can not just go door-to-door with this," he said during an interview. "Administration of oral rehydration needs to be supervised."
DuPont said that about 80% of cholera cases can be treated with oral rehydration therapy, but that many of the cases in Haiti are not identified until it is too late-- highlighting the importance of antibiotics which decrease the bacterial counts in the body.
Explaining the outbreak
Most experts, including Robin Nandy, MBBS, MPH, Senior Health Advisor with Emergencies Health Section of UNICEF, believe that consumption of water from the contaminated Arbonite River is the likely source of the outbreak.
"The river runs directly through the city," he said in a press release. "Most of the cases reported thus far have occurred in areas close to the river."
Thomas D. Kirsch, MD, MPH, associate professor in the Department of Emergency Medicine at The Johns Hopkins School of Medicine and a member of the Department of International Health at the The Johns Hopkins Bloomberg School of Public Health, visited Haiti 10 days after the quake.
"The [cholera] outbreak is what we have feared since all the camps sprung up after the earthquake," he told Infectious Disease News. "Any time there is crowding, especially into camps with questionable sanitary conditions, the chance of an outbreak of diarrheal disease goes up markedly."
DuPont agreed, but said that he did not necessarily believe that a cholera outbreak was inevitable, even in the devastated conditions of Haiti. "This is a high inoculum illness. It takes hundreds of millions of organisms to make you sick," he said. "This is not something that is transmitted simply by handshake."
That said, DuPont noted that cholera occurs in individuals who are poorly nourished or in poor health. "Generally, healthy individuals can not develop cholera easily," he said. "Stomach acids need to be neutralized before this infection can develop." He said that more communicable pathogens such as Shigella were expected, but cholera was not. "Cholera has to be introduced into an environment," he said. "Something helped to produce this problem. Travelers may have brought it in. We would not have anticipated this."
Conversely, some have expressed fears that the vast number of international volunteers moving in and out of the country may spread the disease to other parts of the world. However, because of the specific conditions required to transmit the disease, DuPont believes that such an occurrence is unlikely.
"There is a tremendous amount of illegal movement between the borders of Haiti and the Dominican Republic," he said. "Poor populations in the Dominican Republic could be in trouble."
Moving forward
Andrus said that keys to minimizing the number of people infected through mitigating measures will be frequent hand washing, personal hygiene, safe water use and food preparation. He said that mortality rates can be stemmed through effective case management that prevents severe dehydration.
Kirsch cited the 1994 outbreak of cholera in the Rwandan refugee camps that killed an estimated 12,000 people, and noted that "rapid intervention and transmission control is critical."
DuPont said that no matter which interventions are implemented, there may be as many as tens of thousands of cases. "There will be a lot of deaths not because it is untreatable, but because people will not be able to get to oral rehydration centers," he said. "We need to take this opportunity to educate Haitian citizens on the severity of this disease and make sure they reach treatment."
DuPont and Nandy suggested that training health care workers will be a key aspect of the education campaign.
Nandy stressed that children are at particular risk as they progress to severe dehydration more rapidly. "The priority now is to prevent the spread of cholera to more children and to other areas, and to ensure rapid identification and treatment of affected patients," he said.
A final key component to containment of the outbreak will be ongoing surveillance. "We need to ensure that cases are being tracked," Nandy said. "When we see that it spreads to new areas, it can inform response activities."

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