Bubonic plague, which wiped out a third of Europe's population in the middle ages, has reared its ugly head in the African island state of Madagascar where 32 people have died in a fresh outbreak, according to health authorities.

Some 84 suspected cases of bubonic plague – 60 of them thought to be pneumonic or pulmonary plague, a more virulent strain of the disease – have been reported in five of the island's 112 districts in the past month.

Pneumonic plague is caused by the same bacteria that occur in bubonic plague. However, while bubonic plague is usually transmitted by bites from rat-borne fleas and can be treated with antibiotics, pneumonic plague can be inhaled and transmitted between humans without involvement of animals or fleas. If untreated, it has a very high fatality rate, and can kill within 24 hours.

Last year, Madagascar reported 60 deaths from bubonic plague. Poor hygiene and declining living standards as a result of a protracted political crisis since a coup in 2009 are cited as the primary causes of the spread of the disease.