Health

Animal-Borne Diseases

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Zoonotic diseases are diseases that animals and insects can carry and pass on to humans. Some of the most common zoonotic diseases in Larimer County include rabies, West Nile virus, plague, and tularemia.

These diseases are caused by different types of harmful organisms, such as bacteria, viruses, parasites, and fungi, which are carried by wild animals and insects. For example, mosquitoes can spread the West Nile virus, while fleas on rodents can carry the bacteria that causes plague. Rabies is usually spread through the bite of an infected animal, and tularemia can be transmitted by handling infected animals or being bitten by ticks.

Contact with infected animals or insects through their saliva, urine, feces, or bites is one of the most common ways people are exposed. In some cases, diseases can also spread through contaminated soil, dust, or water. 

The Zoonosis Program helps manage the health risks posed by wild animals, insects, and other pests that carry diseases through the following services:

  • Community education and outreach about zoonotic diseases
  • Monitoring trends, and specimen testing.
  • Tracking animal activity and deaths, and sharing information with the public, homeowner associations (HOAs), cities, and parks and recreation districts.
  • Working with local agencies to manage animal bites and assess potential rabies exposure for people and pets.

More Information About Animal-Borne Diseases

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What is Tularemia?   
Tularemia is a bacterial infection most commonly transmitted to humans that have handled infected animals.

How is tularemia transmitted?  
Infection can arise from handling infected animals, as well as from the bite of infected insects (most commonly ticks and deer flies), by exposure to contaminated food, water, or soil, by eating, drinking, or direct contact with breaks in the skin, and by breathing in dust stirred up during mowing or moving hay, grass, grain, or soil contaminated by an infected animal.

What are the symptoms of tularemia?  
Typical signs of infection in humans are fever, chills, headache, muscle aches, chest pain, and coughing. 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 and swollen glands. Eating or drinking food or water containing the bacteria may produce a throat infection, stomach pain, diarrhea and vomiting. 

Symptoms typically appear between 3 to 5 days of exposure, but can range from 2 - 13 days.

How is tularemia treated?  
Tularemia can be effectively treated with antibiotics, so if you should have any of these early signs, seek medical attention as soon as possible.

Current Risk:  
Larimer County residents are advised that tularemia-causing bacteria are present in much of Larimer County. 

Handling (removing) dead animals: 
NOTE: Tularemia is present in Larimer County. If you had multiple animal die-offs in your area please use caution when handling dead animals.

If you need to remove a dead animal:

  • Apply an insect repellent to yourself against fleas and ticks prior to proceeding with the removal.
  • Use a shovel and place the body in a plastic bag.
  • Dispose of it in an outdoor trash receptacle.
  • Wash your hands immediately.

Steps people can take to prevent human tularemia:

  • Never feed wildlife.
  • Avoid handling any sick or dead animals.
  • Wear gloves when gardening or planting trees.
  • Wear an insect repellent effective against ticks, biting flies and mosquitoes. Repellents that contain DEET or IR3535 are good choices for humans.
  • Wear shoes in areas where rabbits have died. The bacteria can persist in the environment for a month or two, so these precautions should be taken for several weeks.
  • Wear a dust mask when mowing or blowing vegetation in areas where rabbit die-offs have occurred
  • If you hunt rabbits, take appropriate precautions when processing them. Precautions include:
    • When handling rabbits, always wear gloves.
    • Wash your hands after touching any animal, especially before you eat.
    • Cook rabbit meat thoroughly (170 degrees).
    • Wear insect repellents that contain DEET.
    • Only drink water from a safe source.

Tularemia and pets: 
Dogs and cats also get tularemia by eating infected rabbits or other animals, by drinking contaminated surface water, through tick and deer fly bites, and though exposure to contaminated soil if the skin is broken.

If your pet shows symptoms of illness which may include fever, loss of appetite, enlarged lymph nodes, ulcers on the mouth and tongue, draining abscesses, nasal and eye discharge, and skin sores, take it to the veterinarian.

As in humans, tularemia is easily treated if diagnosed early in dogs and cats.

Steps people can take to prevent tularemia in their pets:

  • Routinely apply flea and tick repellent to any pets that go outdoors. Talk to your veterinarian about which choice is best for your pet and follow label directions carefully.
  • Keep your pets leashed when walking them outdoors and keep them away from dead animals.
  • Keep pets from wandering in areas where sick or dead animals have been found.
  • Don't let dogs or cats drink from surface waters (puddles, streams, and ponds) when outdoors.
  • Do not feed them raw meat.
Map of Positive Rabies Animals

What is rabies?     
Rabies is an infectious disease caused by a virus that can affect humans and other animals. The rabies virus affects the nervous system and causes swelling of the brain, eventually resulting in death. Once symptoms appear, the disease is nearly always fatal. Rabies is preventable if vaccines are administered early but the disease is not treatable once symptoms appear.

What animals commonly transmit rabies in Larimer county?     
The virus is most commonly found in skunks and bats in Larimer County, but can also be found in foxes, raccoons and coyotes. Any mammal can get rabies.

Why does public health investigate potential contact with rabid animals?     
Public health can coordinate testing of animals for rabies and help determine if preventive treatment is needed for humans and pets. Public health can also discuss possible exposures and determine risk when an animal is not available for testing. The purpose of these measures is to protect humans and animals from getting rabies.

How is rabies transmitted?     
The virus is transmitted by the saliva of an infected animal, usually through a bite or scratch.  Pets and livestock, especially outdoor animals, can easily come in contact with rabid animals. If your pets are unvaccinated, and they come in contact with a rabid animal, they can contract rabies and spread it to humans and animals.

What are the symptoms of rabies in animals?

  • Normally nocturnal animals such as skunks and bats active during the day
  • Animals stumbling, weak, or paralyzed
  • Unusually aggressive or tame behavior while approaching humans or pets

What can I do to prevent rabies?

  • Ensure that your pets, including horses and livestock, are up to date on their rabies vaccinations.
  • Don’t keep wild animals as pets.
  • Avoid feeding or touching wildlife or feral animals.
  • Avoid animals showing unusual behavior.
  • Prevent contact between pets and wildlife. Obey leash laws.
  • Eliminate food sources for wild animals by not feeding pets outdoors, closing pet doors especially at night, and tightly close garbage cans and feed bins.
  • Put trash in secure bins and animal proof if needed.
  • Prevent wildlife from getting into your house.
  • Teach children to observe wildlife from a distance and to notify an adult if there is a wild animal in the area or if they are bitten or scratched.

What to do if you have an encounter with a sick or dead animal

  • Call the NOCO Humane's Animal Control at 970-226-3647, extension #7, to report a bat, skunk, or other encounters with wildlife that looks sick.
  • Never touch the animal, even if it appears dead
  • Try to contain a bat in the room where it is found. Close the entrances to the room or place a box over it.
  • If the bat, skunk or other animal has bitten or scratched you, wash the affected area immediately and call your doctor as soon as possible.
  • Contact the LCDHE Zoonosis Hotline: 970-498-6666

What if I wake up and find a bat in the house?

  • Trap the bat in one room and contact NOCO Humane Animal Control.
  • Use leather gloves and a box or coffee can and set it over the bat. Use lid to move the bat into the container. Place lid on container and hold for pick up by Animal Control. Do not touch the bat with bare hands!
  • If you are unable to locate the bat or the bat escapes, please contact Larimer County Health Department (970-498-6775) to evaluate the situation and for recommendations for rabies post exposure treatment.
  • The majority of the human cases of rabies in the United States can be associated with a history of waking up with a bat in the bedroom and releasing it without reporting the bat or receive post exposure treatment.

What happens if my pet is exposed to a potentially rabid animal?     
All animal encounters should be reported to animal control or to the Larimer County Department of Health and Environment.  The health department can help evaluate the risk of the exposure and make recommendations for you or your pet. Unvaccinated pets that come in contact with a potentially rabid animal might be required to go through an extensive quarantine process that can be costly, or they might have to be euthanized. Vaccination is the best way to protect your pets from rabies.  

When to call your healthcare provider     
Please consult your healthcare provider or the Larimer County Department of Health and Environment: 

  • If you have had contact with a bat, skunk or other wild animal
  • If you have had contact with feral cats or stray animals
  • If you found a bat in an area where you were sleeping
  • If you are unsure if contact with a bat may have occurred, such as with a child or adult who may not be able to communicate if they had contact

What are the symptoms of rabies in humans?     
Once symptoms appear, rabies is almost always fatal.  Symptoms include tingling or twitching sensation around the animal bite, fever, headache, muscle aches, loss of appetite, nausea and fatigue.  As the infection progresses, irritability, excessive movements or agitation, seizures, inability to swallow and increased salivation can occur.

How long does it take to get rabies?     
It generally takes 20-60 days to develop symptoms of rabies but has been known to be longer than 6 months.

What should I do if I am bitten by an animal?

  • Make note of what animal bit you, what happened, and where the animal went.
  • If the animal bit you in an enclosed area, try and contain the animal. Do not release the animal. If it is caught, it can be tested for rabies. A negative test can mean less health care costs for you after an exposure.
  • Immediately wash the wound with soap and water for at least 15 minutes. Washing the wound thoroughly helps reduce the likelihood of rabies and other bacterial infection.
  • Contact your physician or go to your local emergency room. Bite wounds can be a very serious injury regardless of rabies risk.
  • Report the bite incident to NOCO Humane Animal Control at 970-226-3647 ext 7 and to your local health department.

What is the post exposure treatment for humans?      
If you are bitten or otherwise exposed to a rabid animal you can be vaccinated against rabies. This vaccine is called rabies post exposure prophylaxis (PEP). Call your doctor without delay and report the incident to your the health department.

  • Treatment should start soon after exposure. Talk to your provider or call the Health Department if you have questions.
  • Treatment for rabies usually takes 4 visits, unless the person has been vaccinated previously for rabies.

Protect your pet from rabies:     
Vaccinating pets and livestock for rabies helps to protect you and your family from the virus. Dogs and cats over the age of 4 months are required by law to be vaccinated against rabies in Larimer County.

  • Vaccinate indoor pets
    • Bats can enter houses and even strictly indoor animals sometimes escape. Each year there are pet owners that must make the difficult decision to either euthanize their pet or face an expensive 6 month quarantine because a rabies positive bat came in contact with their indoor pet.
  • Indoor & Outdoor Cats
    • Cats have a natural instinct to hunt, whether they are indoor or outdoor. Sometimes a cat will catch and eat the bat, other times, they may bring the animal they caught into the house or even into a bedroom and share it with their owner.
    • Barn cats have a high risk of rabies exposure since they share their environment with bats and other wildlife. Children many times play with barn cats and the cats have close contact with many other animals on the property.
  • Preventing pet and wildlife conflicts
    • Keep dogs leashed when hiking and walking in your neighborhood. Loose dogs may tangle with a rabid skunk, pick up a bat from the ground, or run into other wildlife without the owner being aware it has happened. Feed your pets indoors. Do not leave pet food outside. Ensure pet doors are locked at night when wildlife is most active. Wildlife frequently visit backyards in search of food and water sources. At night, turn on a light and make some noise prior to letting the dog into the yard to give any wildlife a chance to escape first. Tightly close garbage cans and feed bins. If your pet comes into contact with a wild animal, follow up with your veterinarian.

How is plague transmitted?   
Plague is a bacteria that can be transmitted to people through flea bites and direct contact with infected animals. The bacteria can be carried by fleas, which can be found on rodents like prairie dogs, squirrels, rabbits and chipmunks. When fleas bite rodents infected with plague, they become infected and can then spread the disease to other rodents, domestic animals and humans.   
In humans, the incubation period is usually 2-7 days.

What are plague types and symptoms?    
There are three main forms of plague:

  1. The most common form is the Bubonic plague, characterized by sudden onset of fever, headache, chills, and weakness and one or more swollen, tender and painful lymph nodes (called buboes). This form usually results from the bite of an infected flea. The bacteria multiply in the lymph node closest to where the bacteria entered the human body. Bubonic plague is the most common form of the disease in humans (about 80% of cases) Typical symptoms include swollen lymph nodes, sudden onset of fever or chills, severe headache, extreme exhaustion, and a general feeling of illness. Bubonic plague can be successfully treated when diagnosed promptly. If you have had a possible exposure to infected rodents or fleas and are experiencing these symptoms, consult a physician as soon as possible.
  2. Septicemic plague occurs when the bacteria enter the bloodstream directly and spread throughout the body. These forms are highly fatal unless treated promptly; unfortunately there are often no localizing signs to suggest plague.
  3. Pneumonic plague can result in human-to-human transmission via spread through respiratory droplets. Patients develop fever, headache, weakness, and a rapidly developing pneumonia with shortness of breath, chest pain, cough, and sometimes bloody or watery mucous.

Untreated bubonic plague has a fatality rate approaching 70%; septicemic and pneumonic plague are fatal without prompt treatment.

Tips to avoid plague: 

  • Avoid contact with all sick and dead rodents and rabbits. Look for the presence of blow flies or dead animal smell as evidence of animal die-offs. Prairie dog colonies that suddenly are not active may also be due to plague activity in the area. Report such die-offs to the Larimer County Department of Health and Environment Zoonosis Hotline at 970-498-6666.
  • While hiking, treat pants, socks, shoe tops, arms and legs with insect repellents. If you hunt or trap rabbits or carnivorous wild animals, wear gloves and a respiratory mask while skinning or handling these animals. Fresh pelts may be treated with flea powder.
  • Cats and dogs can carry plague and infected fleas into the house. Talk to your veterinarian about flea and tick prevention to help protect your pets from plague.
  • DO NOT feed or entice any rodent or rabbit species into your yard, back porch, or patio.
  • Eliminate rodent habitat, such as piles of lumber, broken cement, trash and weeds around your home, outbuildings and cabins.
  • When outdoors, minimize exposure in rodent-infested areas. Do not catch, play with, or attempt to hand feed wild rodents.
  • Sick pets should be examined promptly by a veterinarian.

Plague and pets:
Dogs can get a mild infection and have the ability to recover without treatment.

Cats are infected from flea bites or by direct contact with infected rodents. Plague infected cats will generally have a history of roaming freely in rural or semi-rural areas and their owners often report that they are known predators.

Infected cats frequently exhibit swelling and sores around the mouth, head, and neck, and appear to be ill. Seek veterinary care for such animals. Since domestic cats and dogs can carry infected fleas into the home environment, it is also important to consult your veterinarian for information about flea control for your pets. While dogs rarely appear sick from plague, it is still important that they are treated for fleas as they can still carry them into the home.

Steps people can take to prevent plague in their pets:

  • Keep pets from roaming and hunting in areas where plague has been found.
  • Talk to your veterinarian about using an appropriate flea control product.
  • Sick pets should be examined promptly by a veterinarian.

How is plague treated?    
Plague can be treated if diagnosed in the early stages of disease. If diagnosis and appropriate treatment are delayed, life-threatening complications may follow.

When to contact your doctor:  
A doctor or hospital emergency room should be consulted as soon as symptoms appear and a history of exposure to potentially infected animals is very important in evaluating the risk from plague.

What is Avian Flu?
Highly Pathogenic Avian Influenza (HPAI), also referred to as Avian Influenza Flu, Bird Flu, or H5N1 , is a virus that spreads among wild birds, especially ducks and geese, and domestic birds. HPAI is highly contagious but infected birds may not always appear sick or exhibit symptoms. 

How does HPAI Flu spread?
Wild birds can spread the virus to domestic poultry and can cause large-scale outbreaks of serious disease or death in both commercial and backyard flocks. Highly pathogenic avian influenza (HPAI) strains are deadly to domestic poultry and can wipe out entire flocks within a matter of days.  The virus spread through direct, bird-to-bird contact. The virus can also spread via contaminated surfaces or materials, such as manure; egg flats, crates, or other farming materials and equipment; and people's clothing, shoes, or hands.

Cases of the virus has also been reported other kinds animals such as dairy cows. Additionally, Colorado health officials have also identified the virus it in farm workers who were directly exposed to infected cattle and poultry.

Learn More

Reporting Sick or Dead Birds

  • Wild Birds: If you find three or more dead wild birds in a specific area within a two week period OR if you see live birds showing clinical signs of disease, please contact your local Colorado Parks and Wildlife office.
     
  • Domestic Birds: Veterinarians and backyard, hobby, and commercial producers should report any suspicious disease events in poultry flocks to the State Veterinarian’s using this form. 
     
  • To report sick birds or birds that have died from unknown causes, please call the Avian Health Hotline at Colorado State University (CSU): 970-297-4008

What is hantavirus? 
Hantavirus causes a respiratory disease in people and is transmitted by infected rodents. It is often fatal. It can usually be found in rural areas.

How is hantavirus transmitted? 
Hantavirus is transmitted to people through contact with infected rodents.

Contact includes:

  • Inhaling airborne droplets of an infected rodent’s saliva, urine, or feces.
  • Hantavirus can become airborne if any particles containing the virus are moved around while cleaning or by the wind
  • Eating or drinking food contaminated with an infected rodent’s saliva, urine, or feces.
  • Touching contaminated feces and then touching your face, eyes, nose, mouth, or any open wound.
  • Being bitten or scratched by an infected rodent.

What are possible signs of infestation?  
Rodents:

  • Deer mice are the most common transmitters of hantavirus
  • Other types of mice may also carry hantavirus.

Burrows and nests of mice:

  • Piles of debris such as twigs, insulation, grass, usually in or around wood piles, shrubbery, and piles of debris.

Mouse droppings

  • Look like black grains of rice, usually near the walls and in corners

If you have rodents in your home 
Air Out:

  • Air out any potentially contaminated areas for an extended period of time

Clean up:

  • Wear gloves
  • Spray the area with a bleach mixture solution (1 part bleach to 9 parts water) and let sit for 10-15 minutes
  • Pick up solution with paper towels
  • Wash hands thoroughly after cleaning up

Symptoms

  • Flu-like symptoms with trouble breathing
  • Fever of 101°-104°
  • Abdominal, joint, or back pains
  • Nausea and vomiting (sometimes)
  • Difficulty breathing

Symptoms of hantavirus occur 1 to 6 weeks after exposure. If you think you have been exposed to hantavirus, seek medical attention immediately.

Treatment 
There is no specific treatment, vaccine, or cure for this virus. If symptoms are recognized early, receive medical treatment immediately.

Let your health care provider know that you have been around rodents which will allow them to check for rodent-carried diseases such as hantavirus.

There are disease concerns with both rats, mice and other rodents. These diseases can be spread to humans directly, through handling of rodents, through contact with rodent feces, urine, or saliva, or through rodent bites.

These diseases can be spread to humans directly through handling of rodents, rodent bites, or through contact with rodent feces, urine or saliva.  The best way to preventing human exposure to rodent diseases is effective rodent control in and around the home.

Getting Rodents Under Control
Getting a rodent problem under control can be very frustrating. The keys to rodent control are sealing, trapping and cleaning.

CDC provides some guidance on how to get rodent problems under control: 

Health Department Role
As annoying as bed bugs are, they are NOT a public health threat. The Larimer County Department of Health and Environment does not track or monitor bed bug infestations, nor does the health department do any sort of case management related to bed bug infestations. If you suspect you have a bed bug problem, we recommend you call a professional exterminator for a consultation.

Increasing Bed Bug Problems
In general, bed bugs have become more because of increasing travel, increased reuse and re-sale of household furnishings, and an increase in the bugs' resistance to pesticides.

Recommendations to Deal with an Infestation
Since bed bugs can be very challenging to control, we recommend calling a professional exterminator. They can work with you to properly identify the pest and suggest an appropriate and effective treatment for the problem.

Bed bugs can be very difficult to exterminate from a site once they are established. Homeowners and businesses should be aware that some pesticides are not approved for use inside of the home/business site, or on surfaces such as mattresses where people will come in direct contact with that surface. For safe, lasting, and cost-effective results, it's best not to do it yourself. Application of pesticides is best addressed by a licensed pest control professional.

Possible Indicators of Bed Bugs
You're most likely to see a bed bug infestation on your mattress or pillow because you are more frequently at eye-level with a bed's surface and since you may wake up with visible and itchy bites. But bed bugs are very adept at hiding and reproducing behind floorboards and trim, in upholstered chairs and sofas, and even in the frames of televisions. They will hide until emerging when hungry. Luggage is another common way for bedbugs to get into a home. Be sure to check yours closely after your travels.

Diseases Associated with Bed Bugs
Bed bugs are not significant transmitters of disease; however, the bites can be itchy, and scratching the bites could possibly lead to other infections.

Bed Bugs & Cleanliness
A bed bug infestation does not necessarily indicate a lack of cleanliness of any particular home or lodging. Bedbugs can be introduced into even the cleanest, high-end homes, lodging establishments, apartments or office buildings. Adequate hiding places for the bed bugs (furniture, crevices, cracks, etc.) and a warm blooded host for blood meals are all that are needed to start an infestation once the pest is introduced.

For more information on bed bugs:


Please report three or more dead animals (especially rabbits or rodents) found within an area over a two-week period to the LCDHE Zoonosis Team.

Environmental Health

Zoonosis Hotline: 970-498-6666