Zoonotic Diseases

AnSci Final Exam

What types of disease is rabies?

Viral disease

How is rabies transmitted?

Through saliva (can be inhaled - in caves with bats)

Where is rabies found?

Worldwide (with exceptions to some islands)

Is rabies a large problem?

Yes, there is 1 new infection every 10 minutes

How many people world-wide die from rabies per year?

70,000 people

True or false: Rabies is generally fatal without treatment

True

If you think you are infected, should you wait to see if you get rabies or not?

NO! Once symptoms appear, they are almost always fatal, so treat prophylactically

What does prophylactically mean?

Before the onset of symptoms

What medicine is available to humans with rabies?

Prophylaxis

In what animals is rabies most common in, in Wisconsin

• Bats

• Skunks

• Cattle

• Raccoons

True or false: Rabies can affect all mammals, though some are more commonly affected than others

True

Explain the mode of infection for rabies:

• Virus enters muscle tissue

• Gets to nervous tissue

• Replicates and travels to spinal cord and brain

  • Causes encephalitis

• Travels back out nerves

• Gets in saliva (elsewhere, too)

• Bites or saliva in open cuts transmits rabies 

Clinical Stages of Rabies

1. Prodromal-Incubation Stage

2. Excitative (Furious) Stage

3. Paralytic (Dumb) Stage

4. Death

Prodromal-Incubation Stage Characteristics:

• 2-3 days

• May see subtle temperament changes

Excitative (Furious) Stage Characteristics

• 1-7 days

• Animal is vicious

• Bites are common

• May chew on things

• May drool 

Paralytic (Dumb) Stage Characteristics

• 2-4 days

• Dropped jaw (muscles are paralyzed)

• Heavy drooling

• Incoordination

• Lack of fear of humans

• Can be variable

Human Rabies Symptoms:

• Itching around bite and flu-like symptoms first

• Muscle aches, dilated pupils

• Hypersensitivity to light, sound, etc

• Spasms, convulsions, inability to swallow

• Gradual paralysis until death from respiratory failure

How long does it take for humans to show signs of rabies?

30-60 days (2 weeks - 5 months)H

How long does it take dogs to show signs of rabies?

Rarely more than 2 weeks (but can go to 6 months)

What do you do if you are bitten by a rabid animal?

• WASH well with soap and HOT water (wash for 30-40 seconds or longer)

• Seek medical assistance

• Take note of what animal looked like (trap it if safely possible)

Is rabies a fragile virus?

Yes, it is fragile and destroyed fairly easily

• Soap

• Heat (about 105 F)

• UV light

• Drying out

How do they test for rabies?

By removing the brain

To kill a rabid animal, should you shoot it in the head?

No, because brain is used for testing

What animals must be vaccinated?

Dogs, cats, ferrets

What happens if bitten by a vaccinated dog

• Dog is quarantined for 10 days

• May be in home, if able to keep isolated

• Vet must check on day 1 and day 10

What happens if bitten by an unvaccinated dog?

• Dog must be quarantined in a clinic or euthanized

Are there approved vaccine for wolf hybrids?

No, you can still vaccinate, but if it bites, it will be considered an unvaccinated animal

True or false: Only vaccination by veterinarian is accepted?

True

Number of rabid animal cases in 2023

36 (all bats)

Number of rabid human cases from 2009-2018 in U.S.

25 human cases in U.S. (23 died)

Rabies Survivor:

• 2004

• Girl from Fond du Lac

• Bitten by a bat

• Month later, started showing signs

• First person to survive without treatment prior to onset

What is a common sign of rabies in cows?

The cows bellow and appear to be choking

Why can the choking of rabid cows be dangerous?

Because many farmers and vets reach in cow’s throat to find the choking hazard, but saliva can be transferred into cuts or scratch on teeth

When was Lyme Disease first described?

1977 (relatively new disease)

What type of bacteria is Lyme disease?

Spirochete bacteria

What can Lyme Disease cause?

• Arthritis

• Heart muscle inflammation

• Fever

• Anorexia

• Enlarged lymph nodes

• Shifting-leg lameness (for dogs)

Are vaccines for Lyme disease available?

Yes, for dogs. Treatable with antibiotics, but difficult

What is the main human stage of Lyme Disease?

Bulls eye shaped lesion (70-80%), flu-like symptoms, headaches, body aches

What is the most common Lyme disease vector?

Deer tick

Where do ticks get Lyme disease from?

From small rodents

What is Baylisascaris?

A roundworm found in raccoons with aberrant migration in humans

Where can the roundworms in raccoons travel to?

They can travel to the brain and eventually cause death

What should you avoid to prevent Baylisascaris?

• Avoid raccoons and their droppings

How many of raccoons in WI are infected

About half (50%)

Is Baylisascaris more common in southern or northern WI?

Southern

What was West Nile Virus brought to the U.S?

1999 (fairly new)

How is West Nile Virus transmitted?

By mosquitoes

Where did the mosquitoes get West Nile Virus?

From birds

What percentage of people show severe symptoms from WNV

Less than 1%

What percentage of people show some symptoms of WNV?

About 20%

How to avoid WNV

• Long clothing

• Eliminate water in the yard

• Insect repellant

Other Zoonotic Diseases

1. Psittacosis

2. Tuberculosis

3. Colibacillosis (E. coli)

4. Chlamydiosis

5. Brucellosis (undulant fever)

6. Salmonellosis

7. Toxoplasmosis

8. Ringworm

When was Psittacosis recognized?

in 1895

Psittacosis disease characteristics

• Associated of the condition in humans to psittacine birds

• Pandemic in the early 1930’s before antibiotics became available

• Occasional deaths

What causes Tuberculosis?

Bacteria in genus Mycobacterium

Tuberculosis disease characteristics

• One of the major causes of human death until antibiotics were discovered

• Prevalence of both animal and human forms is associated with overcrowding

What is Colibacillosis an infection with?

Escherichia coli (E. coli)

How many known species of E. coli are there?

+2000

(only a few are both pathogenic for animal and humans)

Colibacillosis disease characteristics

• Infection in both animals and humans is characterized by profuse, watery diarrhea, dehydration, and acidosis 

What causes Brucellosis (undulant fever)?

Brucella abortus with a reservoir in cattle, sheep, goats, deer, swine, and rabbits

How is Brucellosis contracted?

By consuming (unpasteurized or raw) products of the above infected animal

Brucellosis disease characteristics (symptoms)

Very high undulating fever, sweating, fatigue, and rapid weight loss

What is Salmonellosis?

A pathogenic strain of Salmonella (may not affect the host animal such as a turtle)

What is Salmonellosis also called?

Food poisoning

Salmonellosis disease characteristics (symptoms)

• Acute gastroenteritis, vomiting, dirrhead, and dehydration

How to eliminate Salmonellosis

Cooking