Concern over spread of Mumps in the U.S.

Health officials in the United States have voiced concern about an outbreak of mumps in the Midwest and say they believe some people may have become infected on airline flights.

In the state of Iowa more than 600 people are reported to be sick with the mumps virus in an outbreak that began in December 2005.

Mumps is an infection of the salivary glands caused by a virus which causes unpleasant illness including fever, headache, and swelling of the glands around the jaw.

It can sometimes cause more serious complications including meningitis, encephalitis, inflammation of the testicles or ovaries, inflammation of the pancreas and permanent deafness.

Mumps once a common childhood illness was virtually eradicated with widespread use of the measles, mumps and rubella vaccine.

Most of the recent cases have been in college age or older people and although mumps rarely causes serious medical problems, young men who contract the disease can have fertility problems later on.

The U.S. Centers for Disease Control and Prevention says the outbreak has spread across Iowa, and mumps activity, possibly linked to the Iowa outbreak, is under investigation in six neighboring states, including Illinois (4 cases), Kansas (33 cases), Minnesota (1 case), Missouri (4 cases), Nebraska (43 cases), and Wisconsin (4 cases).

The CDC says it is transmitted by coughing and sneezing, is as contagious as influenza and people can pass on the virus from three days before they become ill.

The CDC is apparently using a new system to track two infected people who took nine flights in April which may have spread the disease.

The flights, on Northwest and American Airlines, included stops in Iowa, Minnesota and Missouri and the CDC has asked anyone showing symptoms of mumps to report to state health officials if they had been on the flights in question.

Infectious disease experts have queried the CDC's actions and say the organisation has not fully explained why the general public are being warned about the dangers of acquiring infection from air travel.

Other have also questioned the CDC's plans for monitoring international travelers in case of a pandemic of H5N1 bird flu.

Health authorities believe the viral strain originally arrived via a traveler from Britain which has lower mumps vaccination rates than the U.S., and has been battling with a widespread outbreak for the last three years.