NEW YORK: American health officials in three Midwestern states are scrambling to contain a rare lethal virus that is spread by rodents and monkeys and has never been seen before in the western hemisphere.

At least 28 people have been infected with “monkeypox”, a disease related to smallpox and usually found in central and west African rain forests, although none of the American patients has died.

The infections are thought to have been passed on by prairie dogs, wild rodents that live in holes on the western plains of the US and that have become popular in America’s exotic pet market recently.

The symptoms of monkeypox include fever, headaches, swollen lymph nodes, chills, sweats and a dry cough. Ten days after contracting the disease, patients break out in a rash of blistering pimples filled with pus, which open and produce scabs.

The patients range in age from four to 48, and come from Wisconsin, Illinois and Indiana. Health officials expect the numbers to rise now that the public is on alert for the symptoms. All those infected had recent close contact with prairie dogs.

It does not appear that anyone contracted the virus from another person, doctors say.

The disease has a mortality rate of up to 10 per cent, with young children more likely to perish. However, with better standards of nourishment and medical provision in America, the virus may prove less lethal.

Officials believe the disease may have been carried to the US by Gambian giant pouched rats, which then passed it on to the prairie dogs.

Monkeypox is the latest in a series of new diseases that have recently surfaced in America.—Dawn/The Guardian News Service.