Thursday, July 21, 2011

EID: Cholera In The U.S. Associated With Hispaniola Epidemic

 

 

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Although endemic in many developing countries, due to our modern water and sewage treatment infrastructure, cholera is a rarely reported illness in the United States.

 

In the years between 1965 and 1990, there were only an average of 5 cases each year.

 

Starting in 1991, and running through 1994, a Cholera epidemic swept out of Peru infecting more than 1 million South Americans, and claiming nearly 10,000 lives.

 

During the height of that outbreak, the United States saw a 10-fold increase in cholera cases (n=53/yr), mostly from travelers returning from the afflicted region.

 

When the South American epidemic died down, so did the number of cases identified in the United States.  By the year 2000, the average number of yearly cases in the U.S. had dropped to 6, and most of those had a history of international travel.


Last October, when cholera appeared once again in the Western Hemisphere – this time in Haiti, and quickly spread into the Dominican Republic – concerns over another increase in domestic cholera cases were raised.

 

As expected, given the frequency and relative ease of travel between the United States and Haiti, an increase in the number of cholera cases in the United States was observed during the first six months of the epidemic.

 

Yesterday, the CDC’s EID Journal – in ahead of print dispatch – released a report summarizing the 23 known cases of Cholera that appeared in the U.S. in the wake of the Haitian epidemic.

 

All were associated with travel to Hispaniola (n=22) or the consumption of Haitian food (n=1), and no secondary transmission in the United States was observed.

 

Cholera in United States Associated with Epidemic in Hispaniola

DOI: 10.3201/eid1711.110808

 
Newton AE, Heiman KE, Schmitz A, Török T, Apostolou A, Hanson H, et al.  Emerg Infect
Dis. 2011 Nov;

EXCERPT

Six months after the Hispaniola cholera epidemic started in Haiti, 23 associated cases
were recognized in the United States. All cases were associated with recent travel to Hispaniola
or with consumption of seafood from Haiti.

 

The risk for cholera transmission in the United States is low because of improved water and sanitation, and there is no evidence of secondary
transmission. Florida, New York, and Massachusetts have the highest populations of persons of
Haitian or Dominican ancestry (6).

 

Most cases were reported from Florida, the state with the largest Haitian population. However, case-patients also resided in states with small Haitian and Dominican populations.

Travel between the United States and Haiti is straightforward; 4 US airports  offer daily direct flights from Florida and New York to Port-au-Prince. Many persons, including many of Haitian descent, traveled from the United States to Haiti to help with the response to the January 2010 earthquake in Port-au-Prince.

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Echoing the Latin American cholera epidemic in the 1990s, the number of US cholera cases has increased after the cholera epidemic in Hispaniola. Travelers to cholera-affected areas should be aware of the risk and should follow prevention measures to avoid infection.

 

In particular, travelers visiting friends or relatives may be at higher risk for travel-associated infection (7). Few case-patients had received cholera prevention education (educational materials available at www.cdc.gov/cholera/index.html); no cholera vaccine is licensed in the United States.

 

Until cholera in Haiti and Dominican Republic resolves, clinicians, microbiologists, and public health workers in the United States should be prepared for more cases in travelers returning from Hispaniola.

 

 

While obviously a public health concern, the good news here is that the primitive sanitary conditions needed to facilitate ongoing sustained transmission of cholera are largely absent in the United States.

 

International travel to developing countries  - whether for business, pleasure, or to assist in post-disaster recovery operations - has many rewards. The risks of contracting an illness like cholera – while not zero – with proper preparation are generally manageable.

 

As we saw advised earlier this week in MMWR: Dengue Among Travelers Returning from Haiti, international travelers should seek pre-travel health counseling to receive information about travel-related disease risks, and ways to prevent them.