South Africa is one of nine countries warned by the World Health Organization (WHO) to be on high alert for plague.
The other eight countries are the Comoros, Ethiopia, Kenya, Mauritius, Mozambique, France’s La Réunion, the Seychelles and Tanzania.
Plague outbreak in Madagascar
This follows the recent outbreak in Madagascar in September 2017 where 124 people have died and 1 133 people have been infected.
In Madagascar cases of bubonic plague are reported nearly every year, during the epidemic season (between September and April).
What is plague and how is it transmitted?
Plague is an infectious disease caused by the bacteria Yersinia pestis, a zoonotic bacteria, usually found in small mammals and their fleas. It is transmitted between animals through fleas.
Humans can be infected through:
- the bite of infected fleas
- unprotected contact with infectious bodily fluids or contaminated materials
- the inhalation of respiratory droplets/small particles from a patient with pneumonic plague.
People infected with Y. pestis often develop symptoms after an incubation period of one to seven days.
Bubonic and pneumonic plague
There are two main forms of plague infection depending on the route of infection:
- Bubonic plague is the most common form of plague and is caused by the bite of an infected flea. Plague bacillus, Y. pestis, enters at the bite and travels through the lymphatic system to the nearest lymph node where it replicates itself. The lymph node then becomes inflamed, tense and painful, and is called a ‘bubo’. At advanced stages of the infection the inflamed lymph nodes can turn into open sores filled with pus. Human to human transmission of bubonic plague is rare. Bubonic plague can advance and spread to the lungs, which is the more severe type of plague called pneumonic plague.
- Pneumonic plague, or lung-based plague, is the most virulent form of plague. Incubation can be as short as 24 hours. Any person with pneumonic plague may transmit the disease via droplets to other humans. Untreated pneumonic plague, if not diagnosed and treated early, can be fatal. However, recovery rates are high if detected and treated in time (within 24 hours of onset of symptoms).