UN launches in Haiti second phase of vaccination campaign against cholera

The campaign aims to vaccinate 200,000 people living in the communes where the disease persists in particular the department of Artibonite, Central and West. The action was taken pursuant to the recommendations of the Technical Advisory Group of the Pan American Health Organization (PAHO / WHO) on preventable diseases.

According to these experts, oral vaccines two doses against cholera are safe and provide durable protection close to 70% and are effective for a period of two years in endemic areas.

In August 2013, a similar campaign a two-dose was conducted by the Government of Haiti with the support of the United Nations and was able to reach a population of about 107,000 people distributed in the municipalities of Petite Anse in North and Cerca Cavajal in the Central Plateau.

This campaign is a priority measure in the context of the struggle for the elimination of cholera, complementary to other interventions for prevention and response implemented since the epidemic began in October 2010.

In addition to emergency action, the UN supported the government on longer term initiatives, including the campaign for total sanitation, jointly launched in July by Prime Minister Laurent Lamothe and the Secretary-General of the United Nations during his visit to Haiti.

Cholera is believed to have been introduced to the Caribbean island by UN peace keeping forces, since Haiti had no cases reported for over a century. Allegedly the bacteria, according to the identified type originated in Nepal.

cholera bacteria from Haiti changed its DNA in order to fight phages

In the battle between our immune systems and cholera bacteria, humans may have an unknown ally in bacteria-killing viruses known as phages.

In a new study, researchers from Tufts University School of Medicine, Massachusetts General Hospital, Partners In Health, and Haiti’s National Public Health Laboratory, reported that phages can force cholera bacteria to give up their virulence in order to survive.

Phages are viruses that infect bacteria. They first determined that cholera bacteria from Haiti changed its DNA in order to fight phages, reports Tufts University.

The study published in eLife found that cholera’s mutational escape from phage predation occurs during human infection.

The researchers analyzed phage resistance properties and DNA sequences of cholera bacteria taken from phage-positive stool samples from patients with cholera in Haiti and Bangladesh, two countries where cholera outbreaks are common at present.

The researchers compared the bacteria from Haiti to bacteria from Bangladesh, all collected over many years to best determine if the changes were happening on multiple occasions in both countries or only in isolated groups or cases.

The team discovered that across both time and geography, the cholera bacteria mutated during human infection in order to trade their virulence—ability to persist and make a human sick—for the ability to defend against the phages.

Alternatively, in some patients, the cholera bacteria mutated in a more conservative manner to retain virulence, yet sacrificed the ability to grow optimally in the environment. In either scenario, the cholera bacteria appear to have traded something important in order to survive the onslaught from phages.

“This is the first time we have seen cholera bacteria defend themselves from phages while infecting humans. This suggests that these phages are actively working in our favor, first by killing cholera bacteria within the patient, and, second, by genetically weakening the bacteria that are shed by the infected patient such that they are less fit to survive in the environment or less able to cause infection in other people,” said senior author Andrew Camilli of Tufts University School of Medicine.

“Seeing this rapid evolutionary change in the cholera bacteria occurring during human infection suggests that the phages are posing a very strong threat. And to observe this in two different continents suggests that this is not a one-time find, but that it may be happening consistently during cholera outbreaks,” said Kimberley Seed, lead author of the study.

The World Health Organization reports that there are an estimated three to five million cases of cholera and 100,000 to 120,000 deaths due to cholera each year.

“This important finding suggests that we may be able to leverage the strength of phages for treating people with cholera or perhaps preventing cholera in people who may have been recently exposed as an alternative to antibiotics,” said Camilli.