#Plague: Don't panic, experts say

File image: wild rodents are also carriers of the plague. Pexels

File image: wild rodents are also carriers of the plague. Pexels

Published Nov 3, 2017

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South Africa hasn't had a case of reported human plague in 35 years - and experts are allaying fears of a possible resurgence.

Since August, more than 1 300 suspected cases of plague have been reported in Madagascar, with 93 people dead in its wake.

"Black death" - a term scientists don't even use anymore has been widely used in news headlines rousing fears that the epidemic that killed millions of people in Europe in the middle ages could be back with a vengeance.

"Firstly it's not appropriate to use that term. We have a range of antibiotics and treatments that readily treat it, and with this current plague, there are no signs that it is resistant to antibiotics". Professor John Frean from the National Institute for Communicable Diseases (NICD) said this week.

The NICD's Frean and Professor Lucille Blumberg both explained that the plague was a disease that had existed in many regions for millions of years, most commonly in bubonic form - meaning it was spread by infected fleas from the rodent hosts to humans.

While the plague is an annual occurrence in Madagascar, this year's outbreak has raised particular concerns as it is affecting urban centres, mainly in its pneumonic form, spreading from person to person via respiratory droplets.

"I think what's important to note is there are no cases of the plague in SA  nor are there cases of exported plague", Blumberg said.

The World Health Organisation (WHO) warned SA  and eight other countries to take precautionary measures earlier in October, but also added that there were no travel and trade restrictions for Madagascar.

"The risk of international spread remains very low. Madagascar has a number of prevention measures in place such as exit screenings and we as SA also have entry screenings. Our systems are working wells and the outbreaks seem to be under control. Treatment, which lasts about a week also is highly effective," Blumberg assured.

SA  has one direct flight a week from Madagascar and travellers are also screened on arrival for fever or a cough, and ill passengers are assessed at the airport clinic.

She added, "Our advice to travellers has been to avoid flea bites by using insecticide repellents and to take medication to prevent malaria. The risk may be very low but we must be vigilant".

Key facts on the plague by WHO:

-Plague is caused by the bacteria Yersinia pestis, a zoonotic bacteria usually found in small mammals and their fleas.

-People infected with Y. pestis often develop symptoms after an incubation period of one to seven days.

-There are two main clinical forms of plague infection: bubonic and pneumonic. 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.

-Plague can be a very severe disease in people, with a case-fatality ratio of 30% to 60% for the bubonic type, and is always fatal for the pneumonic kind when left untreated.

-Antibiotic treatment is effective against plague bacteria, so early diagnosis and early treatment can save lives.

-From 2010 to 2015 there were 3248 cases reported worldwide, including 584 deaths.

-Currently, the three most endemic countries are the Democratic Republic of the Congo, Madagascar, and Peru.

Signs and symptoms (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.

There are two main forms of plague infection, depending on the route of infection: bubonic and pneumonic.

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).

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