Sept. 28, 2011— -- Despite the Jensen Farms' cantaloupe recall in Colorado, the number of people diagnosed with listeriosis continues to grow. So far, 13 people have died and 72 people have been infected in 18 states according to the latest numbers released by the Centers for Disease Control and Prevention.
"This is the deadliest outbreak of a food borne disease that we've indentified in more than a decade," said Dr. Thomas Frieden, director of the CDC. "For the public, it's important to know that if you know the cantaloupe you have is not Jensen Farms, then it's OK to eat. But if you're in doubt, throw it out."
Government investigators are continuing to search for the root cause of the outbreak, examining the possibility of animal or water contamination as well as the farm's harvesting practices. In the meantime, the number of people infected is expected to rise because it can take up to two months for people infected with the bacteria to develop listeriosis.
"We do anticipate there will be a rising number of cases in the days and weeks to come," Frieden said.
The death toll may be as high as 16 if tests confirm the bacteria was responsible for three new deaths in New Mexico, Kansas and Wyoming.
So far, four people in New Mexico and one person in Kansas have died from the outbreak, as well as two people in Colorado, two in Texas and single deaths in Maryland, Missouri, Nebraska and Oklahoma, according to the CDC. The Wyoming death would be the first in that state tied to the cantaloupe contamination.
"We believe that it is connected based on patient history and presence of listeria; however we do not yet have molecular lab confirmation for the specific outbreak strains," Wyoming Department of Health spokeswoman Kim Deti told ABCNews.com.
In some states where patients have become ill, officials have not yet connected the illness to cantaloupe.
Sarah Weninger, an epidemiologist at the North Dakota Department of Health told ABCNews.com today that a Stutsman County woman in her 60s was diagnosed with listeria on Sept. 23 and has been discharged from the hospital.
"She is a match for the outbreak, but we haven't confirmed that she consumed the recalled product," Weninger said.
Families Sue Jensen Farms
Several families have filed lawsuits against Jensen Farms in Granada, Colo.
Herbert Stevens of Littleton, Colo., bought half of a Jensen Farms cantaloupe wrapped in plastic at a local grocery store on Aug. 10 and the 84-year-old developed tremors on Aug. 22.
"On the 24th, he got really weak and was in a sitting position and couldn't get up," his daughter, Jeni Exley, told ABCNews.com.
Stevens' wife called 911 and he was taken to a hospital, where doctors discovered he had a fever of 102.7. By the end of the weekend, he had been diagnosed with listeriosis.
Antibiotics destroyed the listeria in Stevens' body, but he remains weak and it's unclear when -- if ever -- he'll be able to leave the long-term care facility where he's been living for the past week.
"He is making some progress but still relies on a walker to walk and assistance with activities of daily living," Exley said.
Prior to contracting the bacteria, Stevens was able to walk without assistance and was in good health. He often took trips abroad with his family, most recently to Sweden.
Right now, however, "He sleeps for most of the day," said Exley. "This has played havoc with his whole body."
Stevens' 81-year-old wife, Elaine, tested negative for listeria. The CDC has cautioned that the amount of bacteria it takes to produce listeriosis can differ depending on the person.
There are four different listeria strains associated with the cantaloupe outbreak, something the F.D.A. considers unusual.
"The reasons for that are under investigation," said FDA senior advisor Dr. Sherri McGarry.
Today the F.D.A. said the latest outbreak is yet another reason to fully implement the Food Safety Modernization Act.
The act was signed into law on Jan. 4, but when the F.D.A.'s budget was slashed by the U.S. House of Representatives, it became unclear how the agency would pay for a new, modernized food safety inspection process.
"We're going to take these lessons learned, share that with our partners and industries, CDC and the states, and what we want to do is we want to really prevent this from happening in the future," McGarry said of the listeria investigation.
Listeria can cause fever, neck stiffness, confusion and vomiting, according to the CDC. The elderly and those with weakened immune systems are at a greater risk of developing serious symptoms. Listeria is especially dangerous during pregnancy and can infect the newborn or lead to premature delivery.
Although there have been other listeria outbreaks in recent years, this is the first one attributed to whole cantaloupes, according to the FDA.