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The Bubonic Plague Is Still Killing People in Madagascar

Since the 1990s, the plague has become endemic to Madagascar, with the most recent outbreak flaring up in the capital city of Antananarivo in November.
January 28, 2015, 5:05pm
Photo by Flickr/NIAID

The plague outbreak that has taken hold in slums throughout the capital of Madagascar in recent months has now claimed more than 50 lives and infected at least 213 people, nearly twice the amount reported by the World Health Organization (WHO) in November.

As the agency confirmed the rise in cases, up from 119 confirmed infections as of November 16, it also highlighted concern that a recent tropical storm that hit the island nation last week could lead to further spread of the deadly bacterial disease, or the appearance of other rodent-borne epidemics. The typhoon and cyclone combo displaced tens of thousands of people and countless rats. The rodents can carry the plague before their fleas, in some cases, transmit it to humans.

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WHO's Director-General Margaret Chan dedicated a portion of her executive board session speech on Monday to discuss the spread of the plague in the country, noting that it was an outbreak "receiving very little attention."

"This is the kind of geographically focused and readily manageable outbreak that WHO was designed to contain," she said.

Since the 1990s, the plague has become endemic, or regularly occurring, in Madagascar, with the most recent outbreak flaring up in the capital of Antananarivo in November, after the first case was documented in a village at the end of August.

Dr. Stephen Morse, an epidemiology professor at Columbia University, told VICE News that the country has a long history of sporadic plague outbreaks, and when it comes to the disease, by and large, Madagascar "is not so exceptional." The virus crops up from time to time in places like Vietnam, as well as sporadic instances in the US. Even the subways of New York City are home to the Norway rat species that makes a good host for the so-called "black death."

The Hot Zone: Black death returns to Madagascar. Read more here.

Poverty, unplanned urbanization, and a poor healthcare system all contribute to the problem in Madagascar, while generally the plague is a disease that kills quickly and is difficult to detect.

This time around, however, some concern is being raised over the urban spread, as well as the form of plague spreading in Madagascar. When the disease, caused by the Yersinia pestis bacterium, showed up in Antananarivo in November, WHO warned about the potential for "rapid spread" of the plague due to the dense population and weak healthcare system in the country's largest city.

These concerns have been emboldened by the fact that 8 percent of cases to date in the current Madagascan outbreak have developed into the lethal and more transmissible pneumonic form. This percentage is up from the 2 percent that WHO reported in November.

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Typically, the bubonic plague is transmitted between rats by fleas carrying the disease. Occasionally, these fleas bite and infect humans, typically due to some natural occurring event like a massive rat die-off, according to Morse. In these instances, Morse said fleas become desperate for blood and seek out humans as a source.

The form of the plague that fleas typically inflict on humans causes an enlarged lymph node and cannot be transmitted from person to person. If the bacteria from the disease enters someone's lungs, however, it can then be spread between humans via droplets emitted when coughing.

"It doesn't spread quite as much as the flu in this case," Morse said, but it becomes a "much more efficient transmission method than being bitten by fleas."

Another one of the "disturbing dimensions" of the current outbreak in Madagascar that Chan mentioned on Monday was that the fleas in Madagascar appear to have built up a resistance to deltamethrin, the first-line of insecticide used against the parasites. This was a problem highlighted earlier in the outbreak, with the WHO stating that the observed immunity had "further complicated" the situation.

On top of spreading more easily, pneumonic plague is considered one of the most deadly infectious diseases, according to the WHO. This form of the plague can kill someone within 24 hours after being infected, with a patient's outcome largely dependent on how soon treatment is started.

In general, bubonic plague reacts well to treatment given in the early stages of infection. On Monday, Chan highlighted important progress that has been made in the way of detecting the disease. Together, the WHO and the local partner it supports, Institut Pasteur, have created an inexpensive test that brings back a plague diagnosis in 15 minutes.

"Usually the problem is diagnosing it in time," Morse said, explaining that you can treat the plague with medicine, but added that the infection moves very quickly. "Once a person becomes infected you really need to recognize it and treat it quickly."

Follow Kayla Ruble on Twitter: @RubleKB

Photo by Flickr/NIAID