tularemia organism
Tularemia organism

UTSA research team closer to tularemia therapy

By Christi Fish
Public Affairs Specialist

(Feb. 3, 2009)--Researchers are closer to developing therapies to combat the deadly tularemia infection, according to a study published Feb. 2 in the Proceedings of the National Academy of Sciences Early Edition.

Karl Klose, director of the South Texas Center for Emerging Infectious Diseases (STCEID) and UTSA professor of microbiology, said his lab collaborated with researchers at the Burnham Institute for Medical Research, University of Texas Southwestern Medical Center at Dallas and Thomas Jefferson University in a study that discovered that Francisella tularensis makes an essential metabolic molecule, nicotinamide adenine dinucleotide (NAD), using a different process and different enzyme from all other living organisms.

F. tularensis is a highly infectious organism that causes morbidity and mortality in humans. Very little is known about its molecular mechanisms of pathogenesis (origination and development), and no vaccine is available for protection against tularemia, the disease it causes. Consequently, there is great concern about its role as a potential bioweapon.

However, the researchers' findings are promising. Because F. tularensis makes NAD using a unique pathway that is not used by humans, that pathway can be targeted to destroy the tularemia organism without doing damage to the human host.

"There is a 'conventional' way to make NAD, nicotinamide adenine dinucleotide, in all living organisms studied thus far ranging from bacteria to humans," said Klose, whose lab studies the genetics behind the virulence of F. tularensis. "Our study uncovered that Francisella makes NAD in a very unique way, using the enzyme nicotinamide mononucleotide synthetase, or NMS. The findings offer us a possible target for the development of therapeutics against tularemia."

>> Learn more about UTSA research.

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Agent: Francisella tularensis
Disease: Tularemia or Rabbit Fever

(from Frontier Web site)

F. tularensis is usually found in animals, particularly rodents and rabbits, and is typically associated with rural areas. Each year in the U.S. there are approximately 200 human cases of tularemia reported. Individuals usually become infected through bites from infected insects like ticks and flies, handling infected animals, eating or drinking contaminated food or water, or inhaling airborne bacteria.

F. tularensis causes bioweapons concern because only a small number of the bacteria are needed to cause disease. If the bacteria were used as a bioweapon they would likely be released into the air to cause infection by inhalation. This type of infection would cause fever, headaches, cough and muscle aches. Infected individuals would likely develop pneumonia and other respiratory infections.

Individuals exposed to F. tularensis may not show tularemia symptoms for up to two weeks. However, there are several different types of antibiotics capable of treating tularemia after an individual shows symptoms.