Monday, June 29, 2015

Colorado’s Recent Spate Of Tularemia Infections



# 10,271


Although Lyme disease, Ehrlichiosis and Rocky Mountain Spotted fever tend to grab the bulk of our attention when it comes to tick borne diseases in North America, there are a number of less well-known nasties including STARI (Southern Tick Associated Rash Illness), Babesia, the recently discovered Heartland and bourbon viruses, and the multi-vectored bacteria called Tularemia.


First isolated a little over 100 years ago (1911) in ground squirrels in Tulare County, California - Francisella tularensis  is a gram-negative coccobacillus that is zoonotic and has been reported in every state of the US except Hawaii. It is most prevalent in the south central United States, the Pacific Northwest, and parts of Massachusetts, including Martha's Vineyard.


While often a tickborne disease, Tularemia can also be spread via biting flies (deer flies), via direct contact with infected animals, and even through the inhalation of dust or aerosols contaminated with F. tularensis bacteria.  It is even possible to contract the bacteria through drinking contaminated water, although this is fairly rare in the United States.

Hunters are at particular risk because of potential tick exposure and hunting activities such as skinning infected game.  While often called `Rabbit Fever’, many other wild animals are known to carry this bacteria, including muskrats, prairie dogs and other rodents. The CDC warns that domestic cats are very susceptible to tularemia and have been known to transmit the bacteria to humans.


Nearly half of all US tularemia infections are reported from the 4-state block of Missouri, Arkansas, Oklahoma, and Kansas.


Symptoms (and prognosis) of the disease depends upon the mode of infection.  Deer fly and tick bites usually result in the Ulceroglandular form of the disease, with localized infection and enlarged lymph nodes. Ocular (from touching the eyes with contaminated hands) and Oropharyngeal (from eating or drinking contaminated items) infections are also possible. 


The most severe form – pneumonic – can occur when the bacteria are inhaled, or another mode of infection goes untreated and spreads through the bloodstream.  As far as diagnosis and treatment is concerned, the CDC has this to say:

Diagnosis & Treatment

Tularemia can be difficult to diagnose. It is a rare disease, and the symptoms can be mistaken for other more common illnesses. For this reason, it is important to share with your health care provider any likely exposures, such as tick and deer fly bites, or contact with sick or dead animals. Blood tests and cultures can help confirm the diagnosis. Antibiotics used to treat tularemia include streptomycin, gentamicin, doxycycline, and ciprofloxacin. Treatment usually lasts 10 to 21 days depending on the stage of illness and the medication used. Although symptoms may last for several weeks, most patients completely recover.


Although not normally considered a hotbed of tularemia infections, last year Colorado unusually reported 16 cases, and this year has already recorded 11 cases.   Prior to 2014, Colorado averaged 3 or 4 cases a year.  The following alert comes from the Colorado Department of Health.



News: Eleven tularemia cases identified in Colorado this year

Mark Salley, Communications Director | 303-692-2013 |


DENVER — According to the Colorado Department of Public Health and Environment, there havebeen 11 human cases of tularemia in Colorado since May of this year. Sixteen human tularemia cases were reported in 2014, the second highest number of cases in Colorado since 1983 when there were 20 cases. The previous average was fewer than four cases a year.

People can get tularemia if they handle infected animals, such as rabbits, rodents or hares, or are bitten by ticks or deer flies. They also can be exposed by touching contaminated soil, drinking contaminated water or inhaling bacteria.

Anyone who becomes ill after exposure to a sick or dead animal, or after spending time in areas where sick or dead wild animals have been seen, should talk to a health care provider about the possibility of tularemia. Tularemia is treatable with antibiotics.

Symptoms of tularemia include abrupt onset of fever, chills, headache, muscle aches, joint pain, vomiting, dry cough and difficulty breathing. Other symptoms are skin ulcers, swollen and painful lymph glands, inflamed eyes, sore throat, mouth sores, diarrhea or pneumonia. Tularemia often is overlooked as a diagnosis because it is rare, and the symptoms are similar to other diseases. The incubation period (from being exposed to becoming ill) for tularemia is typically 3 to 5 days, but can range from 1 to 14 days.

Individuals who became sick this year reported engaging in activities such as gardening, mowing, soil excavation, construction, ranching and farming. Few reported seeing any sick or dead animals in the days prior to their illness onset. Many of the 2015 patients were ill for several weeks before receiving antibiotic treatment.

To avoid exposure to tularemia, state Public Health Veterinarian Jennifer House recommends people:

  • Wear gloves while gardening or landscaping, and wash your hands after these activities.

  • Use a dust mask when mowing or doing yard work. Do not mow over animal carcasses.

  • Do not go barefoot or wear sandals while gardening, mowing or landscaping.

  • Dispose of animal carcasses by using a long-handled shovel to place them in a garbage bag. Put the bag in an outdoor garbage can.

  • Wear an insect repellent effective against ticks, biting flies and mosquitoes when hiking, camping or working outdoors. Effective repellants contain 20 to 30 percent DEET, picaridin or IR3535.

  • Do not drink unpurified water from streams or lakes or allow your pets to drink surface waters.

  • Prevent pets from hunting or eating wild animals. Contact a veterinarian if your pet becomes ill with a high fever and/or swollen lymph nodes.

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