Health
experts say UN troops could have caused Haiti cholera outbreak, call
for investigation
By: JONATHAN M. KATZ Associated Press, November 4, 2010
See: UN
responsibility to Haiti for importing cholera by
Ezili Dantò, May 6, 2011
PORT-AU-PRINCE, HAITI — Researchers should determine whether United
Nations peacekeepers were the source of a deadly outbreak of cholera
in Haiti, two public health experts, including a U.N. official, said
Wednesday.
The U.S. Centers for Disease Control and Prevention found that the strain
of cholera that has killed at least 442 people the past three weeks
matches strains found in South Asia. The CDC, World Health Organization
and United Nations say it's not possible to pinpoint the source and
investigating further would distract from efforts to fight the disease.
But leading experts on cholera and medicine consulted by The Associated
Press challenged that position, saying it is both possible and necessary
to track the source to prevent future deaths.
"That sounds like politics to me, not science," Dr. Paul Farmer,
a U.N. deputy special envoy to Haiti and a noted expert on poverty and
medicine, said of the reluctance to delve further into what caused the
outbreak. "Knowing where the point source is — or source,
or sources — would seem to be a good enterprise in terms of public
health."
The suspicion that a Nepalese U.N. peacekeeping base on a tributary
to the infected Artibonite River could have been a source of the infection
fueled a protest last week during which hundreds of Haitians denounced
the peacekeepers.
John Mekalanos, a cholera expert and chairman of Harvard University's
microbiology department, said it is important to know exactly where
and how the disease emerged because it is a novel, virulent strain previously
unknown in the Western Hemisphere — and public health officials
need to know how it spreads.
Interviewed by phone from Cambridge, Massachusetts, Mekalanos said evidence
suggests Nepalese soldiers carried the disease when they arrived in
early October following outbreaks in their homeland.
"The organism that is causing the disease is very uncharacteristic
of (Haiti and the Caribbean), and is quite characteristic of the region
from where the soldiers in the base came," said Mekalanos, a colleague
of Farmer. "I don't see there is any way to avoid the conclusion
that an unfortunate and presumably accidental introduction of the organism
occurred."
Cholera, which had never before been documented in Haiti, has killed
at least 442 people and hospitalized more than 6,742 with fever, diarrhea
and vomiting since late October. It is now present in at least half
of Haiti's political regions, called departments.
Death occurs when patients go into shock from extreme dehydration. The
epidemic has diverted resources needed for the expected strike of a
hurricane this week, and could spread further if there is flooding.
Suspicions that the Nepalese base could have been a source of the infection
intensified Monday after the CDC revealed the strain in Haiti matches
those found in South Asia, including Nepal.
But nothing has been proven conclusively, and in the meantime the case
remains politically charged and diplomatically sensitive. The United
Nations has a 12,000-strong force in Haiti that has provided badly needed
security in the country since 2004. But their presence is not universally
welcomed, and some Haitian politicians have seized upon the cholera
accusations, calling for a full-scale investigation and fomenting demonstrations.
Laurie Garrett, senior fellow for global health at the Council on Foreign
Relations, said it is clear that the disease was imported to Haiti but
that it is still not clear by whom or how. She said the epidemic will
contain lessons for humanitarian relief work and disaster relief around
the world.
"It has to be either peacekeepers or humanitarian relief workers,
that's the bottom line," she said.
Mekalanos said researchers might be more aggressive in finding the source
of the infection if the case was less sensitive.
"I think that it is an attempt to maybe do the politically right
thing and leave some agencies a way out of this embarrassment. But they
should understand that ... there is a bigger picture here," he
said. "It's a threat to the whole region."
He also cast doubt on U.N. military tests released this week that showed
no sign of cholera. The tests were taken from leaking water and an underground
waste container at the base a week after the epidemic was first noted
and processed at a lab in the neighboring Dominican Republic, U.N. spokesman
Vincenzo Pugliese said.
Mekalanos said that it is extremely difficult to accurately isolate
cholera in environmental samples and that false negatives are common.
The Nepalese troops were not tested for cholera before their deployment
if they did not present symptoms. But health officials say 75 percent
of people infected with cholera bacteria do not show symptoms and can
still pass on the disease for weeks.
A spokesman for the World Health Organization said finding the cause
of the outbreak is "not important right now."
"Right now, there is no active investigation. I can't say one way
or another (if there will be). It is not something we are thinking about
at the moment. What we are thinking about is the public health response
in Haiti," said spokesman Gregory Hartl.
The Harvard experts said more conclusive evidence would be available
following closer examinations of the genetic material in the strain.
CDC spokeswoman Kathryn Harben said in an e-mail that the center will
make the full genomic DNA sequence available when it is confirmed.
"At some point in the future, when many different analyses of the
strain are complete, it may be possible to identify the origin of the
strain causing the outbreak in Haiti," she said.
Farmer, who co-founded the medical organization Partners in Health that
is a leading responder in the epidemic, said there is no reason to wait.
"The idea that we'd never know is not very likely," he said.
"There's got to be a way to know the truth without pointing fingers."
___
Associated Press reporter Colleen Barry in Geneva contributed to this
article. |
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Study
bolsters UN source for Haiti's cholera outbreak
Lisa Schnirring * Staff Writer | Source: CDC - Center
for Infectious Disease Research & Policy
(See: UN
responsibility to Haiti for importing cholera by
Ezili Dantò, May 6, 2011)
May 9, 2011 (CIDRAP News) – An epidemiologic study by French researchers
of the initial days of Haiti's cholera outbreak builds a stronger argument
linking the importation of the bacteria to the arrival of United Nations
(UN) peacekeepers from Nepal than a recent report from the UN's independent
experts did.
News of the group's findings was leaked to the media in early December
2010, and the full findings appeared May 6 in an early online posting
by Emerging Infectious Diseases (EID). The report details a field investigation
conducted by the French researchers and their colleagues with Haiti's
health ministry.
On May 4 an independent expert group working on behalf of the UN issued
the results of its 5-month investigation into the source of Haiti's
cholera outbreak, which stopped short of blaming Nepalese UN peacekeepers.
The group said the evidence overwhelmingly supported human activity
as the source but that the pathogen couldn't have spread without deficiencies
in Haiti's water, sanitation, and health systems.
So far Haiti's cholera count is 285,931 cases, including 4,870 deaths,
according to the latest report from the Pan American Health Organization
(PAHO).
When the outbreak first surfaced, some public health officials thought
the contamination could be related to the massive earthquake that had
occurred in January 2010. However, rumors also circulated that sick
Nepalese soldiers imported the disease into Haiti and dumped sewage
into the Artibonite River. As other theories emerged to explain Haiti's
first cholera outbreak in nearly a century, an early analysis suggested
that the Vibrio cholerae strain was from outside Haiti, perhaps from
southern Asia or eastern Africa.
The investigators reported that Nepal's capital, Kathmandu, reported
a cholera outbreak in September 2010, shortly before the UN soldiers
departed for Haiti.
In the French and Haitian investigation, researchers built a database
early in the outbreak, which began in mid October 2010, to identify
clusters and analyze the disease's rapid spread in Artibonite department.
They did field interviews with health groups and government officials
and explored environmental risks in communities and cholera treatment
centers.
They found that the first patients were a family living in Meille, a
village that hosted a UN peacekeeping camp located above a stream that
flowed into the Artibonite River. Nepalese soldiers began arriving at
the location shortly before the family got sick. Haitian epidemiologists
had observed that a pipe from the camp discharged sewage into the stream,
which villagers used for cooking and drinking.
Soon afterward, cholera illnesses were detected in Mirebalais, where
local people used water from the river while their water system underwent
repair. Prisoners at a facility that obtained drinking water from the
river were also sickened
The researchers noted that cholera cases dropped soon after sanitary
problems at the UN camp were corrected, but then spiked again in November.
The outbreak was explosive in communities along the Lower Artibonite
River and then spread into the Artibonite Basin, they reported.
The investigators wrote that the remoteness of Meille and the absence
of other newcomers "make it unlikely that a cholera strain might
have been brought there another way." They added that DNA genotyping
suggests the source was point contamination from a distant source.
They suggested that sewage from asymptomatically infected soldiers probably
wouldn't have created a large enough infectious dose to cause severe
illnesses downstream, and said they believe symptomatic cholera infections
occurred among the Nepalese soldiers inside the UN camp.
"Whatever its cause, this violent outbreak in Lower Artibonite
provoked the flight of persons and resulted in a wave of epidemics that
spread centrifugally and overwhelmed the nascent sanitarian response,"
the article states. "This wave explains the difference between
the delayed and progressive starting of epidemics in the south and the
immediate impact of cholera in the north."
The report shows the usefulness of accurate field reporting to help
focus response efforts, especially when an outbreak involves a newer
pathogen or develops quickly, the researchers said.
Though the epidemiologic report doesn't pinpoint the exact contamination
event, the findings serve as a reminder that military camp sewage should
be handled properly and that aid organizations should avoid adding risks
that don't already exist, they emphasized.
In an editorial in the same issue of EID, Dr Scott Dowell and Dr Christopher
Braden, both from the US Centers for Disease Control and Prevention
(CDC), wrote that the French and Haitian study provides circumstantial
evidence that fecal contamination of a stream initiated the outbreak,
and that the Nepalese soldiers might have been the source. Dowell directs
the CDC's division of global disease detection and emergency response,
and Braden is a medical epidemiologist who directs the CDC's division
of foodborne, waterborne, and environmental diseases.
Though the spread within days to remote parts of Haiti suggests travel
of infected patients played a role in spreading the outbreak, "there
is little doubt that the organism was introduced to Haiti by a traveler
from abroad, and this fact raises important public health considerations,"
they wrote.
Public health experts have noted that Haiti was vulnerable because its
population was naive to the disease, but Dowell and Braden said the
pathogen did not cause major outbreaks in other countries, such as the
Dominican Republic, that reported cases linked to Haiti's cholera outbreak.
They wrote that improving water and sanitation conditions is Haiti's
best hedge against future cholera outbreaks.
They lauded the public health response, which in about 4 months helped
reduce cholera mortality to less than 1%. "Even as we continue
to learn more about the intercontinental spread of this ancient human
scourge, we are reminded of the continued effectiveness of traditional
public health control measures," the two conclude.
See also:
May 6 Emerg Infect Dis study
May 6 Emerg Infect Dis editorial
May 3 PAHO update
May 5 CIDRAP News story "Experts
link Haiti cholera outbreak to human actions, foreign strain"
Dec 8, 2010, CIDRAP News story "Experts
disagree on Haiti cholera source as cases near 100,000"
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