South Africa is among the British holiday hotspots identified by the World Health Organization as priority countries to get ready to defend against the black death.
Madagascar is facing a worrying spread of the deadly disease, with 124 people killed already.
A total of 1,133 people have been infected across the country, with the risk of further spread of the disease “very high” according to latest WHO analysis.
As well as South Africa, Mauritius, Seychelles, Tanzania, La Réunion, Mozambique, Kenya, Ethiopia and Comoros have all been put on notice.
Unicef, the Red Cross, the Centers for Disease Control and Prevention (CDC) and the European Centre for Disease Prevention and Control (ECDC) have mobilised emergency plans in the countries.
They aim to increase public awareness to increase surveillance, particularly at borders, draw up contingency plans and sourcing medication.
In WHO’s latest update on the outbreak, the body said: “Nine countries and overseas territories have been identified as priority countries in the African region for plague preparedness and readiness by virtue of having trade and travel links to Madagascar.
“WHO is prepositioning equipment and supplies, including personal protective equipment, antibiotics and other equipment required to safely identify plague cases, in Comoros, Mauritius, Mozambique, Seychelles, and Tanzania.”
It added: “Due to the increased risk of further spread and the severe nature of the disease, the overall risk at the national level is considered very high. The risk of regional spread is moderate due to the occurrence of frequent travel by air and sea to neighbouring Indian Ocean islands and other southern and east African countries, and the observation of a limited number of cases in travellers.”
The plague has a 30 to 100 per cent chance of death if left untreated.
Elhadj As Sy, secretary general of the International Federation of Red Cross and Red Crescent Societies, said: ”The number of cases is growing by the day.
“Our volunteers are working in communities convincing people to seek help.”
Plague symptoms include sudden fevers, head and body aches, vomiting and nausea.
Bubonic plague – the most common form of plague – can causes inflamed lymph nodes, which can then turn to puss-filled, open sores if the condition worsens.
It can develop to pneumonic plague, if the infection spreads to the lungs.
The bubonic plague is transmitted to humans by infected fleas.
The majority of those reported by WHO had developed to pneumonic.
Last week the United Arab Emirates issued travel advisories warning tourists to avoid Madagascar.