On November 18, three cases of the plague, two pneumonic and one bubonic, were confirmed in China [1,2,3,4]. The first two cases, reported on November 12, were an inner-Mongolian husband and wife . For treatment, the couple was transported to a hospital in Beijing on November 3, raising question about the nine-day delay in officials reporting the plague cases . The third case was reported by health authorities in the Inner Mongolia Autonomous Region on November 16, in a 55-year old man, also from inner Mongolia, who had killed and eaten wild rabbit on November 5 [1,2]. Authorities are stating there is no epidemiological link between the two instances and are reassuring the public not to be concerned, despite the lack of transparency and information being shared around the cases [2,3]. The couple has been reported to have pneumonic plague and the man has been reported to have bubonic plague [1,2].
Both pneumonic and bubonic plague are caused by Yersinia pestis . The plague has been known to have up to a 90% fatality rate, when infections are left untreated . Treatment usually consist of several antibiotics generally used to treat enterobacteria (gram negative rods) [2,5]. Specifically, this includes gentamicin, fluoroquinolones, streptomycin, and more . Bubonic plague is the more common form and can develop into pneumonic plague when the infection advances to the lungs, causing shortness of breath, headache, and coughing [2,3]. The plague is most well-known for the “Black Death” that killed about one-third of Europe’s population in the 1300’s . Millions of people have been killed by the plague through the centuries .
In China specifically, there have been 26 plague cases, and 11 deaths, between 2009 and 2018 . The last major outbreak occurred in 2009, in the town of Ziketan, in Qinghai province on the Tibetan Plateau, resulting in several deaths . It is common for hunters to be among cases as Y. pestis is carried by fleas, which bite animals including rabbits, rodents, and other small mammals that are hunted [2,5]. In 2014, a 38-year old person died of bubonic plague in Yumen, China and in 2018, the growing rodent population in Mongolia led to a “rat plague” resulting in $86 million (600 million Yuan) in damages . It is thought that Y. pestis originated in China and spread to the west and rest of the world via ships . Plague cases are rare, but between 2010 and 2015, the World Health Organization (WHO) reported 3,248 cases worldwide, resulting in 584 deaths . The U.S. has an average of 7 plague cases per year, with cases reported in semirural and rural areas of northern New Mexico, northern Arizona, southern Colorado, California, southern Oregon and far western Nevada .
In response to the three 2019 confirmed cases in China, contacts of the pneumonic plague cases were placed under medical observation and 28 contacts of the bubonic plague case have been quarantined, none having presented with symptoms [2,7]. As of November 25, the Inner Mongolia Health Commission reported no additional cases . Forty-six of the pneumonic plague cases contacts had been released from observation and 8 of the bubonic contacts had been released from quarantine . However, on November 28, a fourth case (bubonic plague) was reported by Chinese health authorities, in the same region as the other cases . This case of bubonic plague is a rural herder in Siziwang county who was known to have been in the area of identified plague sources. The individual is stable at a local hospital and four people have been quarantined in response to this case .