Zoonoses: Disease from Animals to Humans

Zoonoses: Disease from Animals to Humans

BACKGROUND

If you live in the front range area, you’re probably exposed to animals on a daily bases, whether working on a farm full of cattle herds and horses, pets at home, or even just walking through a park and seeing squirrels. Here are some warnings you should be aware of.

Zoonosis or Zoonoses (pl.) are any diseases caused by infectious agents that are transmitted from animals to humans. The infectious agents that cause Zoonotic diseases include bacteria, viruses, parasites, and fungi. Zoonotic diseases represent significant public health threats, but many of them can be avoided. In Larimer County, these include, but are not limited to: Plague, Rabies, Tularemia, West Nile Virus, Colorado Tick Fever, Hanta Virus, and Western Equine Encephalitis.

Zoonotic diseases have various ways of spreading, making them very hard to cure. Most Zoonotic diseases are transferred by direct contact with infected animals. For example, Tapeworms can often spread to humans when people eat the infected meat of cattle and swine. Other diseases are transferred by insect vectors which are often blood-feeding insects that carry the cause of the disease from one animal to another.

LIST OF AGENTS

Bacterial

· Plague (apply link)

· Tularemia (apply link)

· Lyme Disease (apply link)

Viral

· Rabies (apply link)

· Dengue Fever (apply link)

· Hanta Virus (apply link)

· West Nile Virus (apply link)

· Yellow Fever (apply link)

Parasitic (apply link)

Fungal (apply link)

CARRIERS

The following is a partial list of animals and the diseases that they may carry. Not all animal carriers are listed, nor are all the diseases that the various species can carry.

· Bats

o Commonly known to carry the virus that causes Rabies and also carry several other viral diseases that can affect humans.

· Cats

o Can carry the causative organisms for Plague, Anthrax, cowpox, Tapeworm, and many bacterial infections.

· Dogs

o May carry Plague, Tapeworms, Rabies, Rocky Mountain Spotted Fever, and Lyme disease.

· Horses

o Can carry Anthrax, Rabies, and Salmonella infections.

· Cattle

o May carry the organisms that cause Anthrax, European tick-borne encephalitis, Rabies, Tapeworm, Salmonella infections and many bacterial and viral diseases.

· Pigs

o Best known for carrying Tapeworm, but also carry a large number of other infections including Anthrax, Influenza, and Rabies.

· Sheep and goats

o May carry Rabies, European tick-borne encephalitis, Salmonella infections, and many bacterial and viral diseases.

· Rabbits

o May carry Plague and Q-Fever.

· Birds

o May carry Campylobacteriosis, Chlamydia psittaci, Pasteurella multocida, Histoplasma capsulatum, Salmonellosis, and others.

PLAGUE

What is the Plague?

You’ve probably heard of the “Black Plague” from your high school history class, but it’s actually part of a larger Zoonotic disease simply called the Plague. It is a bacterial disease of rodents that can spread to humans and other animals by infected fleas. There are three major forms of the disease:

· Bubonic Plague is an infection of the lymph nodes (Black Plague)

· Pneumonic Plague is an infection of the lungs

· Septicemic Plague is an infection of the blood

The organism Yersinia pestis causes Plague. Rodents, such as rats, spread the disease to humans.

How do people get the Plague?

People can get the Plague when a flea that carries the Plague bacteria from an infected rodent bites them. In rare cases, you may get the disease when handling an infected animal. Here are some ways to get Plague:

· By the bites of infected fleas

· By direct contact with the tissues or body fluids of a Plague-infected animal

· By inhaling infectious airborne droplets from persons or animals, especially cats, with Plague pneumonia

· By laboratory exposure to Plague bacteria

What are the signs and symptoms of the Plague?

Bubonic Plague symptoms appear suddenly, usually after 2-5 days of exposure to the bacteria. Symptoms include:

· High fever

· Smooth, painful lymph gland swelling called a buboe

o Commonly found in the groin, but may occur in the armpits or neck.

o Pain may occur in the area before the swelling.

· Chills

· General ill feeling (malaise)

· Muscle pain

· Severe headache

· Seizures

Pneumonic Plague symptoms appear suddenly, typically 2-3 days after exposure. They include:

· Severe cough

· Frothy, bloody sputum

· Difficulty breathing

Septicemic Plague may cause death even before the symptoms occur. Symptoms can include:

· Abdominal pain

· Blood clotting problems

· Diarrhea

· Fever

· Low blood pressure

· Nausea

· Organ failure

· Vomiting

What is the treatment for the Plague?

If diagnosed in time, Plague is treatable with antibiotics. Treatment of suspected Plague cases should start as soon as possible after the laboratory examinations of the specimen. Streptomycin is usually the antibiotic administered, but several other antibiotics are also effective.

How can the Plague be prevented?

· Do not feed any rodent or rabbit species in the wild.

· When camping or hiking, do not hang around in rodent-infested areas. Do not catch,
play with or attempt to hand feed wild rodents.

· Avoid contact with all sick and dead rodents and rabbits. Look for the
presence of blowflies or dead animal smell as evidence of animal die-offs.

· While hiking, treat pants, socks, shoe tops, arms and legs with insect
repellants.

· Insecticide powders or shampoos should be used on cats and dogs every few
days while in Plague areas.

· Cats sometimes exhibit swelling and sores around the mouth head and neck when infected. Seek professional veterinarian care for such animals and do not handle suspiciously sick pets without gloves and face protection.

· Remember the incubation period of 2-6 days and consult a physician if
sudden unexplained illness occurs within that period after activities in the
outdoors.

Where can I find more information about the Plague?

· CDC (Center for Disease and Control)

o http://www.cdc.gov/ncidod/dvbid/Plague/index.htm

· WHO (World Health Organization)

o http://www.who.int/zoonoses/en/

· Larimer County – Home

o http://www.co.larimer.co.us/

TULAREMIA

What is Tularemia?

Tularemia is a bacterial disease associated with both animals and humans. Many wild and domestic animals can be infected. The rabbit is most often involved in disease outbreaks, which hints at its alternate name, rabbit fever.

Tularemia is caused by the bacterium Francisella tularensis. The primary vectors are ticks and deer flies although it can also spread through arthropods. The most known reservoir hosts include rabbits, prairie dogs, hares, and muskrats.

How do people get Tularemia?

People can get this disease mostly by being involved in outdoor activities. Some of the most common ways are:

· Bites from infected ticks

· Direct contact through the skin or mucous membranes with blood or tissue while handling infected animals (rabbit hunting)

· Contact with fluids from infected deer flies or ticks

· Handling or eating insufficiently cooked rabbit meat

· Drinking contaminated water

· Inhaling dust from contaminated soil or handling contaminated pets or wild animals

The good news about Tularemia is that it’s not spread from human to human.

What are the signs and symptoms of Tularemia?

Symptoms vary, depending on the route of introduction.

Cases of infection after handling an animal carcass:

· Slow-growing ulcer at the site where the bacteria entered the skin (usually on the hand)

· Swollen lymph nodes

Cases when the bacterium is inhaled:

· Pneumonia-like symptoms

o Severe cough

o Frothy, bloody sputum

o Difficulty breathing

Cases when the bacterium is ingested:

· Sore throat

· Abdominal Pain

· Diarrhea and Vomiting

What is the treatment for Tularemia?

Usual cases are treated with Steptomyocin, Gentamicin, Tetracyclin, Chloramphinicol, or Fluroquinolones.

How can Tularemia be prevented?

· Avoid drinking, bathing, swimming or working in untreated water where infection may be common among wild animals.

· Use impermeable gloves when skinning or handling animals, especially rabbits.

· Cook the meat of wild rabbits and rodents thoroughly.

· Avoid being bitten by deer flies and ticks. Here are a few helpful hints:

o Check your clothing often for ticks. Wear light-colored long-sleeved shirts and long pants so the tiny ticks are easier to see. Tuck long pants into your socks and boots. Wear a head covering or hat for added protection.

o For those who may not tolerate wearing all of these clothes in hot, humid weather, apply insect repellent containing DEET. Be sure to wash treated skin after coming indoors. If you do cover up, use repellents while in locations where ticks are common.

o Walk in the center of trails so weeds do not brush against you. Weeds serve good nesting locations for flies and ticks.

o Check yourself, children and other family members every two to three hours for ticks. Most ticks seldom attach quickly and rarely transmit tick-borne disease until they have been attached for four or more hours.

o If you let your pets outdoors, check them often for ticks. Infected ticks also can transmit some tick-borne diseases to them. (Check with your veterinarian about preventive measures against tick-borne diseases.) You are at risk from ticks that "hitch a ride" on your pets but fall off in your home before they feed.

o Make sure the property around your home is unattractive to ticks. Keep your grass mowed and keep weeds cut.

Where can I find more information about Tularemia?

· CDC (Center for Disease and Control)

o http://www.cdc.gov/ncidod/diseases/submenus/sub_tularemia.htm

· WHO (World Health Organization)

o http://www.who.int/zoonoses/en/

· Larimer County – Home

o http://www.co.larimer.co.us/

LYME DISEASE

What is Lyme Disease?

Lyme disease is a bacterial disease transmitted by infected ticks. In the U.S. it’s caused by the bacterium Borrelia afzelii.

How do people get Lyme Disease?

· By the bites of infected deer ticks (black-legged tick)

What are the signs and symptoms of Lyme Disease?

Symptoms vary greatly from one person to another. Symptoms also vary with the length of time a person has been infected.

· Ring-like red rash (grows larger over time)

o Rash usually accompanied by:

· Fatigue, chills and fever

· Headache

· Swollen lymph nodes

· Joint and muscle pain

What is the treatment for Lyme Disease?

Antibiotics are the primary treatment for Lyme disease. Usual cases are treated with Doxycycline, Amoxicillin and Ceftriaxone.

How can Lyme Disease be prevented?

The best way to protect yourself against Lyme disease and other tickborne illnesses is to avoid tick bites. This includes avoiding tick-infested areas. However, if you live in or visit wooded areas or areas with tall grass and weeds, follow these precautions against Lyme disease and other tickborne diseases like Rocky Mountain Spotted Fever and Tularemia.

· Avoid being bitten by deer flies and ticks. Here are a few helpful hints:

o Check your clothing often for ticks. Wear light-colored long-sleeved shirts and long pants so the tiny ticks are easier to see. Tuck long pants into your socks and boots. Wear a head covering or hat for added protection.

o For those who may not tolerate wearing all of these clothes in hot, humid weather, apply insect repellent containing DEET. Be sure to wash treated skin after coming indoors. If you do cover up, use repellents while in locations where ticks are common.

o Walk in the center of trails so weeds do not brush against you.

o Check yourself, children and other family members every two to three hours for ticks. Most ticks seldom attach quickly and rarely transmit tick-borne disease until they have been attached for four or more hours.

o If you let your pets outdoors, check them often for ticks. Infected ticks also can transmit some tick-borne diseases to them. (Check with your veterinarian about preventive measures against tick-borne diseases.) You are at risk from ticks that "hitch a ride" on your pets but fall off in your home before they feed.

o Make sure the property around your home is unattractive to ticks. Keep your grass mowed and keep weeds cut.

Where can I find more information about Lyme Disease?

· CDC (Center for Disease and Control)

o http://www.cdc.gov/ncidod/dvbid/lyme/

· WHO (World Health Organization)

o http://www.who.int/zoonoses/en/

· Larimer County – Home

o http://www.co.larimer.co.us/

RABIES

What is Rabies?

Do you ever wonder why you can’t have squirrels or other really cute looking wild rodents as pets? One of the answers is Rabies. Rabies is a viral infection that affects the nervous system. This Zoonotic disease is known for causing acute encephalitis (inflammation of the brain) in mammals. It is caused by the RNA virus, Lyssavirus , most commonly referred to as the Rabies Virus.

How do people get Rabies?

People get Rabies from infected mammals, most commonly bats. Rabies is transmitted most often through animal bites, although other contact with the saliva or brain tissue of an infected animal can cause the disease. It can also be spread by an unnoticeable bite from a bat with Rabies, even without an obvious wound. There have currently been a few isolated cases of Rabies infection through skunk interactions in Colorado.

What are the signs and symptoms of Rabies?

The Rabies virus travels through the nervous system, eventually inflaming the brain. Early symptoms include:

· Irritability

· Headache

· Fever

· Itching or pain at the site of the bite

The disease progresses if untreated and is accompanied by the following signs:

· Paralysis

· Spasms of the throat muscles

· Convulsions

· Delirium

What is the treatment for Rabies?

As soon as a bite has been identified, it’s important to clean the wounded area to avoid infection. A series of vaccinations after exposure can prevent the disease from worsening and spreading. Once symptoms appear, treatment is highly unlikely to be found and often leads to fatality.

How can Rabies be prevented?

· Do not feed, touch or adopt wild animals or stray dogs or cats.

· Vaccinated pets serve as a buffer between rabid wildlife and humans, so be sure dogs and cats are up-to-date on their Rabies vaccinations. Consult with your veterinarian about when your pet needs to be vaccinated.

· Do not allow pets to roam free.

· Do not attract wild animals to your home or yard. Store bird seed or other animal feed in containers with tight-fitting lids. Feed pets indoors. Make sure garbage cans are tightly capped. Board up any openings to your attic, basement, porch or garage. Cap chimneys with screens.

· Encourage children to immediately tell an adult if they are bitten or scratched by an animal. Teach children not to approach or to touch any animal they do not know.

· Report all animal bites to the local animal control.

· AGAIN, MAKE SURE ALL PETS ARE VACCINATED.

Where can I find more information about Rabies?

· CDC (Center for Disease and Control)

o http://www.cdc.gov/Rabies/

· WHO (World Health Organization)

o http://www.who.int/zoonoses/en/

· Larimer County – Home

o http://www.co.larimer.co.us/

DENGUE FEVER

What is Dengue Fever?

Dengue Fever is a viral disease spread by the bite of infected mosquitoes. Its more sever and often fatal form is called Dengue Hemorrhagic Fever. Dengue and Dengue Hemorrhagic Fever are caused by any of the Dengue family of viruses, Flaviviridae. Infection with one virus does not protect a person against infection with another.