Tracking infectious disease on Twitter
January 10th, 2012
10:34 AM ET

Tracking infectious disease on Twitter

Haitians started dying of cholera just 10 months after the country's devastating earthquake. Researchers say health ministries might have responded more quickly had they seen evidence of the unfolding epidemic in an unlikely place: Twitter.

Putting all publicly-available tweets with the word "cholera" and the hashtag "#cholera" on a timeline, researchers at Harvard Medical School were able to show a surge in cholera-related tweets early in the epidemic. The timeline correlates closely with later health-ministry tallies.

The researchers used tweets from around the world - 65,728 total with the word "cholera" - that were sent between October 20 and November 3, 2010, including those that came from aid organizations and/or media outlets in Haiti and elsewhere.

The goal is to someday harness the immediacy of social media and use it to make better decisions early on about where to deploy public health resources, said Professor John Brownstein of Children's Hospital Boston and co-founder of HealthMap.org, which aggregates global information about infectious diseases. FULL POST

October 13th, 2011
03:25 PM ET

Lesson from Haiti's deadly cholera outbreak

Cholera cases have risen in Haiti, but the number dying from the disease is down, according to researchers from the Centers for Disease Control and Prevention.

“The number of deaths were initially way too high,” said Dr. Robert Tauxe, researcher and deputy director at the CDC. “But within a few weeks of the outbreak, we trained teams to treat the disease and increased access to supplies.”

Tauxe says these improvements lowered the mortality rate from cholera in Haiti from 4% to below 1%, where it's been since December.

Cholera is contracted by consuming food or water contaminated with fecal bacteria. People who live in rural areas with a lack of adequate water treatment and sanitation are more likely to get the disease. While it can cause severe dehydration from rapid loss of body fluids, cholera is one of the easiest diseases to treat with oral rehydration salts.

Access to these very basic supplies was a core challenge in Haiti that led to many deaths soon after the outbreak.


Cholera vaccine, antibiotics urged for Haiti
December 10th, 2010
07:19 PM ET

Cholera vaccine, antibiotics urged for Haiti

The cholera epidemic in Haiti continues to spread, particularly in the rural areas in the north, which has public health advocates calling for more to to be done to try to stem the spread of disease.

In a commentary published Friday in the journal The Lancet, Dr. Paul Farmer, a co-founder of Partners In Health and chair of the Department of Global Health and Social Medicine at Harvard Medical School, calls for more antibiotics and vaccines to be shipped to the small Caribbean nation.

He and his co-authors told reporters Friday that there are still areas and even some camps where only few people have been infected with the waterborne disease, which causes severe diarrhea and dehydration and in extreme cases can lead to death in just a few hours.


Study: Origin of cholera epidemic in Haiti is in humans, not nature
December 9th, 2010
07:20 PM ET

Study: Origin of cholera epidemic in Haiti is in humans, not nature

After studying the DNA of the strain of cholera responsible for the outbreak in Haiti, researchers believe this disease was brought to the Caribbean nation by humans.

Researchers used cutting-edge DNA testing to identify the origins of the bacteria responsible for the large cholera outbreak.  By sequencing the genome of this strain and analyzing the DNA from strains found in Latin America and South Asia, researchers found this Haitian strain of cholera is nearly identical to strains circulating in South Asia, according to a study published online in the New England Journal of Medicine on Thursday.  However, it was distinct from the strain in Latin America, says lead author Dr. Matthew Waldor, a physician and researcher at the Harvard School of Medicine.


November 4th, 2010
05:41 PM ET

TEDMED: Gupta on helping Haiti

CNN Chief Medical Correspondent Dr. Sanjay Gupta couldn't make it to the TEDMED 2010 conference because he was on assignment in Haiti, but he still presented his perspective on covering the earthquake and cholera outbreak there.

In January, in the aftermath of the earthquake, Gupta remembers children running after dump trucks to see if the bodies of their parents or loved ones were inside. "It was as if these people just vanished off the face of the Earth," he said. Some say it will take four years to get Haiti back to the way it was one day before the earthquake, he said.


October 29th, 2010
11:31 AM ET


By Dr. Sanjay Gupta
CNN Chief Medical Correspondent

The tragic story of 22-year-old Saint Helene and her 15-month old daughter Cherie began like many here in Haiti. About two weeks ago, Saint Helene bought a bus ticket to Artibonite, a city about an hour north of Port Au Prince. Visiting with friends there last week, they had likely heard about the cholera outbreak that was unfolding in front of them. The good news: When Saint Helene and Cherie headed back to Port-au-Prince a few days later, they felt perfectly fine. Asymptomatic, as we say in the medical world. What Saint Helene or Cherie could not have known at that time is they were likely carrying the cholera bacteria back to the nation’s capital.

What happened next is not entirely clear. Saint Helene told us she was walking in Port-au-Prince, when she became suddenly ill. Within a couple hours, she was terribly dehydrated from diarrhea, and began to vomit. A good Samaritan brought mother and her young child to the closest hospital, where Saint Helene was taken to a back, somewhat isolated area and began treatment for cholera. She had an IV placed, and was given salts to replace the lost electrolytes. All of this happened within a few hours, relatively speedy, especially given the logistical challenges of Haiti.


October 28th, 2010
11:35 AM ET

Blindsided in the Third World

[cnn-video url=http://www.cnn.com/video/#/video/world/2010/10/28/dnt.gupta.haiti.cholera.aid.cnn]

By Sanjay Gupta
CNN Chief Medical Correspondent

I visited one of the largest warehouses in Port-au-Prince yesterday. It is a large structure behind a big blue gate and a handful of security guards. I went to get a better understanding of how lifesaving supplies are distributed in the middle of a cholera outbreak. Outside, workers from aid organizations were also waiting to take supplies to patients in St. Marks, the epicenter of the outbreak.

It quickly became clear that it was going to be a long day. One of the workers told me she had been waiting for several hours to pick up the supplies despite the fact that she had all the necessary paperwork and authorizations. No one was available to help her. After sitting there frustrated nearly the whole day, she eventually left empty-handed, telling me this wasn’t at all unusual. “Typical Third World red tape,” she added.


October 27th, 2010
05:01 PM ET

Cholera cases rising around the world

Haiti's department of public health has recorded 4,147 confirmed cases and 292 deaths from cholera since the outbreak was reported last week, officials from the Pan American Health Organization (PAHO) announced Wednesday. The PAHO is watching the spread of the disease closely, for fear that cholera could cross the border into the Dominican Republic.

On Tuesday, the United Nations reported Nigeria's worst outbreak in recent years, with more than 1,500 dead.


October 25th, 2010
05:32 PM ET

Was cholera in Haiti before the earthquake?

The fast moving cholera outbreak has sickened more than 3,000 people and resulted in more than 250 deaths in the island nation of Haiti. This infectious disease has not been seen on the island since the 1960s and doctors are working around the clock to get the outbreak under control.

"We expect these cases to increase and infection to emerge," said Dr. Jon Andrus, deputy director of Pan American Health Organization. "We had put in an early warning system to watch for these consequences, since the earthquake on January 12. So we are prepared if the numbers become more widespread. We are ready to handle this infection."

But according to Dr. Anthony Fauci, director, National Institute of Allergy and Infectious Diseases at the National Institutes of Health, the bacteria must have been in Haiti already, beneath the surface, and poor sanitation helped trigger the outbreak.


October 22nd, 2010
02:09 PM ET

Cholera can be deadly within hours

Cholera is a bacterial illness that causes severe diarrhea and dehydration and can be lethal within hours if a person is not treated.

"This is a bacteria that actually is in the environment. It's in brackish water in the river. It can be in seacoasts and if the environmental conditions are not right, the cholera bacteria can grow up and then anyone who ingests that water or food that comes from that water or food that is prepared with that water can get ill," says Dr. William Schaffner, chair of Preventive Medicine at the Vanderbilt University Medical Center.

In an epidemic, cholera can also be spread from the feces of an infected person.  Children and adults alike are vulnerable.  According to the World Health Organization (WHO), three-quarters of people carrying the bacteria have no symptoms. For those who do get sick, the main symptoms include diarrhea, vomiting, muscle cramps, dehydration and shock. Death can occur if treatment is not immediately administered.
While human remains don’t typically pose a health threat, the WHO notes that bodies of people who have died from cholera do pose a health risk and should be kept away from polluting sources of drinking water.

The WHO estimates  3–5 million people are sickened by cholera each year causing 100,000–120,000 deaths.

The bacteria can spread when human waste enters water systems and people drink the contaminated water or eat food that's been cooked in contaminated water.  While modern sewerage systems have almost completely eliminated cholera in industrialized countries, it can thrive in areas where war, disaster, or extreme poverty forces people to live in crowded and unsanitary conditions, according to the Mayo Clinic.

Cholera is easily treated if people can be rehydrated.  In many cases, giving patients oral rehydration salts can help relieve symtoms.  In more severe cases, IV fluids may and antibiotics are required.   According to the WHO, the fatality rate may be 30-50 percent if left untreated.   Two vaccines are available to prevent cholera, but they are not always readily available in situations where disaster and impoverishment flourish.

Improving sewerage and sanitation conditions is the best way to prevent cholera outbreaks and spread, according to the WHO.  But this is not always practical in times of disaster, where food, hygiene and public health tracking may be compromised.

About this blog

Get a behind-the-scenes look at the latest stories from CNN Chief Medical Correspondent, Dr. Sanjay Gupta, Senior Medical Correspondent Elizabeth Cohen and the CNN Medical Unit producers. They'll share news and views on health and medical trends - info that will help you take better care of yourself and the people you love.