Pneumonic plague

The most apparent symptom of pneumonic plague is coughing, often with hemoptysis (coughing up blood). With pneumonic plague, the first signs of illness are fever, headache, weakness and rapidly developing pneumonia with shortness of breath, chest pain, cough and sometimes bloody or watery sputum.

The pneumonia progresses for two to four days and may cause respiratory failure and shock. Patients will die without early treatment, some within 36 hours.

Initial pneumonic plague symptoms can often include the following:

Pneumonic plague can be caused in two ways: primary, which results from the inhalation of aerosolized plague bacteria, or secondary, when septicemic plague spreads into lung tissue from the bloodstream. Pneumonic plague is not exclusively vector-borne like bubonic plague; instead, it can be spread from person to person. There have been cases of pneumonic plague resulting from the dissection or handling of contaminated animal tissue. This is one of the types of plague formerly known as the Black Death.

Pneumonic plague is a very aggressive infection requiring early treatment, which must be given within 24 hours of first symptoms to reduce the risk of death. Streptomycin, gentamicin, tetracyclines and chloramphenicol are all able to kill the causative bacterium.

Antibiotic treatment for seven days will protect people who have had direct, close contact with infected patients. Wearing a close-fitting surgical mask also protects against infection.

The mortality rate from untreated pneumonic plague approaches 100% although victims of the Black Death who vomited blood occasionally survived, such as the chronicler Marcha di Marco Battagli.

Since 2002, the World Health Organization (WHO) has reported seven plague outbreaks, though some may go unreported because they often happen in remote areas. Between 1998 and 2009, nearly 24,000 cases were reported, including about 2,000 deaths, in Africa, Asia, the Americas, and Eastern Europe. Ninety-eight percent of the world's cases occur in Africa.

Two outbreaks occurred in the Democratic Republic of the Congo in 2005 and 2006. The outbreak in 2005 was only detected by looking back at blood samples. The total death toll was 111.

In September 1994, India experienced an outbreak of plague that killed 50 and caused travel to New Delhi by air to be suspended until the outbreak was brought under control. The outbreak was feared to be much worse because the plague superficially resembles other common diseases such as influenza and bronchitis; over 200 people who had been quarantined were released when they did not test positive for the plague. All but three of the deaths occurred around the city of Surat.

A major outbreak of the pneumonic plague occurred in Manchuria from 1910 to 1911, in what became known as the Manchurian plague, killing around 60,000 people. The Qing court dispatched Wu Lien-teh, a doctor educated at Cambridge University, to oversee disease control and treatment efforts. He made the novel observation that the disease was transmitted by air, and developed prototypical respirators to help prevent its spread. A second, less deadly outbreak occurred in 1920–21, killing approximately 9,300 people.

The People's Republic of China has eradicated pneumonic plague from most parts of the country, but still reports occasional cases in remote western areas, where the disease is carried by rats and the marmots that live across the Himalayan plateau. Outbreaks can be caused when a person eats an infected marmot or comes into contact with fleas carried by rats. A 2006 WHO report from an international meeting on plague cited a Chinese government disease expert as saying that most cases of the plague in China's northwest occur when hunters are contaminated while skinning infected animals.

The expert said at the time that, due to the region's remoteness, the disease killed more than half the infected people. …