A plague epidemic in Madagascar has killed 124 people since August in an outbreak that has hit the island's two main cities the hardest, the authorities said.

Plague is endemic in Madagascar, but the outbreak that has caused 1,192 suspected cases since August is especially worrying because it started earlier in the season than usual and has hit urban, rather than rural areas.

Its symptoms are flu-like - fever, chills, body aches, nausea, vomiting, and swelling of the lymph nodes in the groin, neck or armpits.

There are three major types of plague: bubonic, septicemic, and pneumonic. Two-thirds of the cases are of the pneumonic plague.

Pneumonic, the most lethal form has broken out in Madagascar. Highly contagious, it is transmitted from person to person often by coughing. If untreated, it has a fatality rate close to 100 percent and can be fatal within 24 hours of being contracted.

Bubonic plague is spread by fleas or rodents to humans and can spread to a person's lungs. About 10 percent of bubonic plague cases develop to become pneumonic.

The third strain septicemic, when the infection spreads through the bloodstream. This could happen from flea bites or if the bacteria enters through a cut on a person's skin.

"The total number of cases (1,192) is already three times higher than the average annual total," the National Office for Risk and Disaster Management said in a report on Wednesday.

Last week, a World Health Organization report said the death toll stood at 94.

The capital Antananarivo and Toamasina, the two largest cities in Madagascar, an island in the Indian Ocean, were the most affected, with 55 percent of cases recorded there.

To date 54 medical staff have been infected, it said.

The report said that of an estimated $9.5m in aid needed to counter the epidemic, only $3m has been raised.