Bubonic plague in China: All you need to know about 'black death'

A suspected case of bubonic plague was reported in a city in northern China on Sunday. Bayannur, Inner Mongolia Autonomous Region, announced a level III warning of plague prevention and control, state-run People's Daily Online reported.

The suspected bubonic plague case was reported on Saturday by a hospital in Bayannur. The local health authority announced that the warning period will continue until the end of 2020.

While it is unclear how the plague spread, the alert asks people to immediately report any sick or dead marmot (large and heavy rodents that resemble squirrels).

"At present, there is a risk of a human plague epidemic spreading in this city. The public should improve its self-protection awareness and ability, and report abnormal health conditions promptly," news agency PTI said quoting a local health authority.

On July 1, state-run Xinhua news agency said that two suspected cases of bubonic plague reported in Khovd province in western Mongolia have been confirmed by lab test results. The confirmed cases are a 27-year-old resident and his 17-year-old brother, who are being treated at two separate hospitals in their province, it quoted a health official as saying.

What is bubonic plague?

Bubonic plague is a bacterial disease that is spread by fleas living on wild rodents such as marmots. According to WHO, the plague is caused by the bacteria Yersinia pestis, a zoonotic bacteria usually found in small mammals and their fleas.

While there are two main clinical forms of plague infection, bubonic plague is the most common form and is characterized by painful swollen lymph nodes or 'buboes'.

Plague is transmitted between animals and humans by the bite of infected fleas, direct contact with infected tissues, and inhalation of infected respiratory droplets.

How fatal is bubonic plague?

Bubonic plague can be a very severe disease in people, with a case-fatality ratio of 30 percent to 60 percent. According to the World Health Organization (WHO), it can kill an adult in less than 24 hours if not treated in time. From 2010 to 2015, there were 3,248 cases reported worldwide, including 584 deaths.

Historically, plague was responsible for widespread pandemics with high mortality. It was known as the "Black Death" during the fourteenth century, causing more than 50 million deaths in Europe. However, with the availability of antibiotics, the disease is largely treatable now.

Plague epidemics have occurred in Africa, Asia, and South America; but since the 1990s, most human cases have occurred in Africa. The three most endemic countries are the Democratic Republic of Congo, Madagascar, and Peru. In Madagascar cases of bubonic plague are reported nearly every year, during the epidemic season (between September and April).

What are the symptoms of bubonic plague?

As per WHO, people infected with plague usually develop acute febrile disease with other non-specific systemic symptoms after an incubation period of one to seven days, such as sudden onset of fever, chills, head and body aches, and weakness, vomiting and nausea.

The bubonic plague attacks the lymphatic system, causing swelling in the lymph nodes. If untreated, the infection can spread to the blood or lungs.