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Biological Health Hazard – Tularemia (pneumonic human infection): Larimer County, Colorado


Biological Hazard  – Tularemia (Rabbit Fever)

Published Date: 2016-06-18 14:43:10
Subject: PRO/AH/EDR> Tularemia – USA: (CO) pneumonic
Archive Number: 20160618.4295395

Date: Friday, 17 June 2016 12:49:08 PM MDT
Source: Fort Collins (CO) Reporter-Herald [edited]

The Larimer County [Colorado] Department of Health and Environment announced [Fri 17 Jun 2016], that a [Fort Collins] resident, who has not been identified, developed a lung infection in late May 2016 and was hospitalized. He or she is now home recovering from the infection, which is commonly referred to as rabbit fever because of the animal that most commonly carries the bacterium.

People can become infected by handling infected animals, through an insect bite, from contaminated food, or by the droppings or urine of a sick animal. The bacterium in the animal waste can turn to aerosol, and when people mow or turn up the soil, they can inhale the infection.

Health officials believe that is how the Fort Collins resident contracted tularemia, according to a written release. “This person did a lot of lawn mowing and gardening,” said Katie O’Donnell, spokeswoman for the health department.

Tularemia varies in severity from mild illness to even death, though fatalities from the condition are rare, according to health officials. Signs of infection include fever, chills, headache, fatigue, and swollen and painful lymph glands. If the condition is contracted from an insect bite, it often causes a skin ulcer and swollen glands, according to the Larimer health department. If it is contracted through food or water, it may result in a throat infection, mouth ulcers, stomach pain, diarrhea, and vomiting. Inhaling the infection can lead to chest pain and coughing. The condition can be treated with antimicrobials, so residents with these symptoms are encouraged to seek medical attention.

The frequency of human cases appears to be increasing. The Colorado Department of Health and Environment reports 94 total confirmed cases from 2005 through 2015. Of those, 52 occurred in 2015. Larimer County has 12 total reports during that same 10-year period, according to the state health department. 9 of those were in 2015, O’Donnell said.

The bacterium that causes tularemia naturally occurs in rabbits, hares, small rodents, voles, muskrats, and beavers. Therefore, any signs of these species dying off throughout a neighborhood indicate a possible outbreak.

[Byline: Pamela Johnson]

Communicated by:

Date: Friday, 17 June 2016
Source: Larimer County Department of Health and Environment [edited]

The Larimer County Department of Health and Environment has confirmed the 1st human case of tularemia in a county resident in 2016. This patient developed a lung infection, and may have been exposed while mowing the yard or gardening at home in an urban subdivision. Soil can be contaminated by tularemia-causing bacteria from the droppings or urine of sick animals, most often rabbits. When a person mows, blows leaves, or turns up the soil, these bacteria can aerosolize and be inhaled, causing pneumonic tularemia.

All warm-blooded animals are susceptible to tularemia, including livestock and pets such as dogs, cats, and birds, however these bacteria normally occur in nature in rabbits and hares, as well as in small rodents, voles, muskrats, and beavers. A recent die-off of rabbits or rodents in a neighborhood suggests a possible tularemia outbreak among the animals in that area. The bacteria these animals shed can persist in the soil or water for weeks, and it takes very few bacteria to cause an infection.

Tularemia can be transmitted to people, such as hunters, who have handled infected animals. Infection can also arise from the bite of infected insects (most commonly ticks and deer flies); by exposure to contaminated food, water, or soil; by eating, drinking, putting hands to eyes, nose, or mouth before washing after outdoor activities; by direct contact with breaks in the skin; or by inhaling particles carrying the bacteria (through mowing or blowing vegetation and excavating soil). In recent years, most human tularemia cases along the Front Range have been attributed to activities involving soil and vegetation.

Typical signs of infection in humans may include fever, chills, headache, swollen, and painful lymph glands, and fatigue. If tularemia is caused by the bite of an infected insect or from bacteria entering a cut or scratch, it usually causes a skin ulcer or pustule and swollen glands. Eating or drinking food or water containing the bacteria may produce a throat infection, mouth ulcers, stomach pain, diarrhea, and vomiting. Inhaling the bacteria may cause an infection of the lungs with chest pain and coughing.

Tularemia can be effectively treated with antimicrobials. Should you have any of these early signs, seek medical attention as soon as possible. Untreated tularemia can lead to hospitalization and may be fatal if not diagnosed and treated appropriately.

Gardeners, landscapers, mowers, outdoor workers, and others participating in leisure activities outside are advised to:
– wear gloves when gardening or planting trees, and always wash hands before eating or putting hands to mouth, nose, or eyes;
– wear a dust mask when mowing or blowing vegetation, or excavating or tilling soil;
– wear an insect repellent effective against ticks, biting flies, and mosquitoes (DEET, picaridin, or IR3535 are good choices);
– wear shoes, rather than going barefoot, on grassy lawns, especially if dead rabbits or rodents have been seen in the neighborhood;
– never touch dead animals with bare hands

Communicated by:

[ProMED-mail sincerely thanks veterinarian Dr Bob Peterson (<>) who also contributed this report.

The state of Colorado can be located on the HealthMap/ProMED-mail interactive map at Larimer County can be seen on the map at – Sr.Tech.Ed.MJ

The following is extracted from
Pedati C, House J, Hancock-Allen J, et al: Notes from the Field: Increase in Human Cases of Tularemia — Colorado, Nebraska, South Dakota, and Wyoming, January-September 2015.
MMWR Morb Mortal Wkly Rep. 2015 Dec 4;64(47):1317-8;

“Approximately 125 cases have been reported annually in the USA during the last 2 decades. As of 30 Sep 2015, a total of 100 tularemia cases were reported in 2015 among residents of Colorado (n = 43), Nebraska (n = 21), South Dakota (n = 20), and Wyoming (n = 16). This represents a substantial increase in the annual mean number of 4 (975 percent increase), 7 (200 percent), 7 (186 percent) and 2 (70 percent) cases, respectively, reported in each state during 2004-2014.

“Patients ranged in age from 10 months to 89 years (median = 56 years); 74 were male. The most common clinical presentations of tularemia were respiratory disease (pneumonic form, [n = 26]), skin lesions with lymphadenopathy (ulceroglandular form, [n = 26]), and a general febrile illness without localizing signs (typhoidal form, [n = 25]). Overall, 48 persons were hospitalized, and 1 death was reported, in a man aged 85 years. Possible reported exposure routes included animal contact (n = 51), environmental aerosolizing activities (n = 49), and arthropod bites (n = 34); a total of 41 patients reported 2 or more possible exposures.

“Although the cause for the increases in tularemia cases in Colorado, Nebraska, South Dakota, and Wyoming is unclear, possible explanations might be contributing factors, including increased rainfall promoting vegetation growth, pathogen survival, and increased rodent and rabbit populations. Increased awareness and testing since tularemia was reinstated as a nationally notifiable disease in January 2000 is also a possible explanation for the increase in the number of cases in these 4 states. Health care providers should be aware of the elevated risk for tularemia within these states and consider a diagnosis of tularemia in any person nationwide with compatible signs and symptoms. Residents and visitors to these areas should regularly use insect repellent, wear gloves when handling animals, and avoid mowing in areas where sick or dead animals have been reported.”

Tularemia is a classic zoonosis, capable of being transmitted by aerosol, direct contact, ingestion, or arthropods. Inhalation of aerosolized organisms (as in the laboratory or as an airborne agent in an act of bioterrorism) can produce a pneumonic form. Direct contact with or ingestion of infected carcasses of wild animals (such as cottontail rabbits) can produce the ulceroglandular, oculoglandular, oropharyngeal (local lesion with regional inflammation of a lymph node), or typhoidal form. Immersion in or ingestion of contaminated water can result in infection in aquatic animals. Ticks can maintain infection transstadially and transovarially. Transstadial transmission occurs when a pathogen remains with the vector from one life stage (“stadium”) to the next. Transovarial or transovarian transmission occurs in certain arthropod vectors as they transmit disease-causing bacteria from parent arthropod to offspring arthropod, which makes them an efficient reservoir as well as a vector. Recognized vectors in the USA include _Dermacentor andersoni_ (wood tick), _Amblyomma americanum_ (lone star tick), _Dermacentor variabilis_ (dog tick), and _Chrysops discalis_ (deer fly).

Tularemia does not spread from person to person essentially in contradiction to another category A bioterrorism agent, _Yersinia pestis_, in which the pneumonic form can easily be transmitted. – Mod.LL]

See Also

Plague, tularemia – USA (NM) alert 20160615.4289092

Tularemia – USA (18) 20151205.3842058
Tularemia – USA (17): (WY, NE) 20150925.3670429
Tularemia – USA (16): (AZ) rabbits 20150830.3612365
Tularemia – USA (15): (CO) rabbits 20150828.3608721
Tularemia – USA (14): (WY) fatality 20150825.3599260
Tularemia – USA (13): (NM, WY, AZ) human, animal 20150819.3580618
Tularemia – USA (12): (AK) hare, human 20150818.3586385
Tularemia – USA (11): (WY) rabbit 20150802.3553047
Tularemia – USA (10): (CO, SD) 20150801.3548673
Tularemia – USA (09): (CO) muskrat, alert 20150728.3542178
Tularemia – USA (08): (ND): human, animal 20150726.3537551
Tularemia – USA (07): (NM) 20150715.3510564
Tularemia – USA (06): (CO) rabbit, alert 20150703.3482641
Tularemia – USA (05): (AK) susp. 20150702.3480207
Tularemia – USA (04): (CO) rabbit, dog 20150702.3479571
Tularemia – USA (03): (CO) 20150626.3467769
Tularemia – USA (02): (CO) 20150603.3403896
Tularemia – USA: (CO) 20150522.3379806

Tularemia – USA (09): (CO) humans, beavers 20141206.3014671
Tularemia – USA (08): (CO) hunter warning 20141003.2829512
Tularemia – USA (07): (CO) 20140923.2798680
Tularemia – USA (06): (CO) 20140918.2783744
Tularemia – USA (05): (CO) 20140912.2763100
Tularemia – USA (04): (IL, CO) fatal 20140813.2684686
Tularemia – USA (03): (CA) feline 20140711.2602339
Tularemia – USA (02): (NM) 20140711.2601188
Tularemia – USA: (CO) rabbit 20140705.2589884

Tularemia – USA (08): 2001-2010 20131130.2083934
Tularemia – USA (07): (MA) 20130905.1926007
Tularemia – USA (06): (CO) rabbit 20130818.1886594
Tularemia – USA (05): (AK) snowshoe hare 20130702.1802498

A ProMED-mail post
ProMED-mail is a program of the International Society for Infectious Diseases

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