Years after Covid-19 brought the world to its knees, we have reports of a suspected case of pneumonic plague in a laboratory worker in Russia. This raised concerns and questions about the disease, how it spreads and how dangerous it is.
The World Health Organization (WHO) has asked Russia for further information after media reports emerged about the death of a worker at the Irkutsk Antiplague Research Institute in Siberia.
The worker died after being hospitalised with severe pneumonia. Initial reports suggested the illness may have been pneumonic plague following a possible accidental laboratory exposure.
However, WHO said it does not yet have enough information to conduct a full risk assessment.
Russian authorities have said that no recent case of plague had been reported in the Irkutsk oblast and that around 200 contacts had been placed in quarantine.
The authorities have also said that people who had contact with the researcher tested negative for pneumonic plague.
Here is what you need to know about the disease.
What is pneumonic plague?
When we think of a ‘plague’, our minds often go to the bubonic plague. However, pneumonic plague is a severe form of plague that affects the lungs.
Plague is caused by the bacterium Yersinia pestis, which is generally found in small mammals and their fleas.
There are three main forms of plague namely: bubonic plague, which affects the lymph nodes, septicaemic plague, which occurs when the bacteria infect the bloodstream and pneumonic plague, which affects the lungs.
According to the US Centers for Disease Control and Prevention (CDC), pneumonic plague is the most serious form of plague and is the only form that can be transmitted directly from person to person.
Pneumonic plague can develop when untreated bubonic or septicaemic plague spreads to the lungs.
It can also occur when a person inhales infectious droplets released when another person or animal with pneumonic plague coughs.
How does pneumonic plague spread?
Plague bacteria are usually transmitted to humans through infected fleas or contact with infected animals.
A person can become infected after being bitten by an infected flea or after handling an infected animal.
Pneumonic plague is different because it can also spread directly between people. A person with pneumonic plague can release infectious droplets when coughing, and another person can become infected by inhaling those droplets.
However, this type of transmission generally requires close contact.
Pneumonic plague can also occur when someone already infected with another form of plague develops an infection in the lungs.
How quickly can symptoms appear?
One of the reasons pneumonic plague is considered particularly serious is its short incubation period.
The CDC says the incubation period following inhalation can be as short as one day.
The disease can then progress rapidly.
Symptoms can include:
- Fever
- Headache
- Weakness
- Shortness of breath
- Chest pain
- Coughing
- Bloody or watery mucus
Because the symptoms can develop quickly and resemble those of other serious respiratory infections, rapid medical assessment and treatment are important where there has been a potential exposure.
Is pneumonic plague fatal?
Pneumonic plague is potentially life-threatening, especially when treatment is delayed.
According to the CDC, it is the most serious form of plague.
Can pneumonic plague be treated?
While the plague is potentially life-threatening, it can be treated.
Plague can be treated with antibiotics, particularly when treatment begins early.
The WHO has previously highlighted the importance of rapid diagnosis and treatment because pneumonic plague can progress quickly.
Because of the potential seriousness of the infection, people who have had a high-risk exposure may be offered antibiotics to prevent infection, as well as being placed under quarantine or monitoring.
Why might contacts be quarantined?
If pneumonic plague is suspected, health authorities may need to identify and monitor people who could have been exposed.
This is particularly important because of the possibility of person-to-person transmission.
Gibani said people with a high-risk potential exposure could be offered post-exposure prophylaxis with antibiotics and/or quarantine.
In the reported Russian case, authorities said about 200 contacts had been quarantined.
WHO has asked Russia for more information about the health status of those contacts and the laboratory testing carried out on them.
Is pneumonic plague common?
The pneumonic plague is not common. While the plague still occurs in parts of the world, human infections are relatively uncommon.
The number of cases of all forms of plague varies from year to year and is estimated to be between about 1,000 and 3,000 globally.
Most cases are bubonic plague.
Human cases can occur in areas where the bacterium is maintained in animal populations, including parts of Africa, Asia and the Americas.
Russia can also experience plague because natural reservoirs of Yersinia pestis exist in parts of the region.
What happened in Russia?
On October 2, media reports emerged about the death of a laboratory worker at the Irkutsk Antiplague Research Institute.
The worker had been hospitalised with severe pneumonia and subsequently died.
Some reports suggested the worker may have contracted pneumonic plague after an accidental laboratory exposure.
WHO said it was aware that the Russian government had held a meeting on October 2 after a resident of the Irkutsk oblast was suspected of having a dangerous infection.
On Saturday, WHO requested further information from Russia under the International Health Regulations.
Russia subsequently responded, saying no recent case of plague had been reported in the Irkutsk oblast.
The country also said about 200 contacts had been placed in quarantine.
However, WHO said it had requested additional information about the laboratory tests conducted on the person who died and the contacts.
It also wants more information about what prompted the public health measures and the current health status of those contacts.
WHO said it had also sought verification of reports about a second employee who had developed pneumonia of undetermined cause.
Has Russia confirmed that the worker had plague?
Not at this stage, based on the information provided by WHO.
The circumstances surrounding the death are still being investigated.
Russian authorities have said tests showed “no microorganisms associated with the patient’s professional activities”.
WHO has said it does not yet have the full picture of the event and therefore cannot conduct a complete risk assessment.
The organisation has offered Russia technical support relating to plague and laboratory biosafety and biosecurity.
Does this mean there is a wider outbreak?
There is currently no indication in the information provided by WHO that the Russian incident represents a wider international outbreak.
The issue is that the exact cause of the worker’s illness and death has not been fully established.
WHO has stressed the importance of timely, complete and transparent information sharing under the International Health Regulations so that conflicting reports can be clarified and the potential public health risk accurately assessed.
What about the Black Death?
Plague is often strongly associated with the Black Death, which was the devastating pandemic that killed millions of people in Europe during the 14th century.
There is debate over the precise contribution of different forms and transmission routes of plague to historical pandemics.
What is clear is that Yersinia pestis is the bacterium responsible for plague and that it continues to exist in animal reservoirs today.
But what makes it different is that modern medicine has also changed the situation considerably.
Unlike during historical pandemics, plague can now be diagnosed and treated with antibiotics, while public health authorities can use surveillance, contact tracing, infection control and quarantine measures to reduce transmission.
So, should people be worried?
The reported Russian case is being investigated, and WHO has made clear that it needs more information before it can assess the risk fully.
Pneumonic plague itself is a serious disease and can become fatal if treatment is delayed. It is also capable of spreading from person to person through respiratory droplets.
But it is an uncommon infection, and effective antibiotics are available.
For now, the most important distinction is between a suspected or reported case that is still being investigated and a confirmed outbreak.
WHO’s request for further information is part of the international process for establishing what happened, whether the worker was infected with plague, whether anyone else was infected and whether there is any wider public health risk.
Until those questions are answered, the available information does not establish that there is a broader outbreak of pneumonic plague.
IOL
