There has been a dramatic rise in the number of Legionnaires disease cases in the United States. According to the country’s health officials, the number of cases reported in the month of August is more than double of what was expected for that month.

When inquired, experts are saying that they haven’t yet managed to pinpoint any single cause of this surge. According to them, the epidemic is caused by a combination of several factors. Some of the most prominent ones among them are: aging population of the country that has greater susceptibility to illness, multiple environmental factors, better diagnostics and improved awareness of the infection.

This summer, so far, has seen 12 individuals in Bronx borough, New York and 8 living in an Illinois veterans’ home being killed by the Legionella bacterium. Recently, a significant rise in cases of the disease has been observed among prisoners at California’s San Quentin State Prison.

These recent figures clearly show that there has been an acceleration from the most recently obtained national data, which reveals that the number of cases reported to the country’s public health bodies has become more than three times between the years 2001 and 2012.

Dr. Matthew Moore of the US Centers for Disease Control and Prevention (CDC) said that it’s not yet clear to them whether that rise actually represents a rise in disease or indicates something else. Dr. Moore adorns the position of a medical epidemiologist at the CDC.

CDC has recently revealed that during the four weeks ending on August 29, a total of 404 cases of Legionnaires disease, Legionellosis and a related condition known as Pontiac Fever have been reported to the American health authorities. This number is double than what was expected from that particular 4-week period.

The year 1976 saw Legionnaires being reported in the US for the first time. The most extreme cases of the disease might result in symptoms such as severe pneumonia, kidney failure, septic shock and respiratory failure.

People develop the condition after inhaling water droplets or mist infected with the bacterium called Legionella. It’s a waterborne bacterium that cannot spread from one person to another. Legionella grow rapidly in warm water and thus infections caused by this bacterium are more common during the summer months.