Zoonotic Diseases Flashcards
Zoonotic Diseases
Diseases that can be transmitted from animals to humans
Rabies
- Viral Disease
- Transmitted in saliva
- Found world-wide (exceptions)
- Large problem:
- 1 new human infection every 10 mins
- Kills more than 55,000 ppl per year (world)
- Generally fatal without treatment
Rabies: Important Problems
- Can’t wait to see if you get rabies or not
- Once symptoms appear, nearly always fatal
- So treat prophylactically, just in case
- before onset of symptoms
- Treatment given to 40% of children in Africa and Asia
Rabies in WI
Most commonly found in WI in:
* bats
* skunks
* cattle
* racoons
Can affect all mammals, though some more commonly affected than others
Rabies mode of infection
- virus enters muscle tissue
- gets to nervous tissue - where it likes to multiply
- replicates and travels to spinal cord and brain
- causes encephalitis
- virus travels back out nerves
- gets in saliva (elsewhere, too)
- bites or saliva in open cuts transmits rabies
Dog Stage 1: Prodromal - incubation stage (2-3 days)
may see subtle temperament changes
Dog Stage 2: Excitative (Furious) stage (1-7 days)
- animal is vicious
- bites are common
- animal may chew on things
- may drool
Dog Stage 3: Paralytic (dumb) stage (2-4 days)
- dropped jaw (muscles are paralyzed)
- heavy drooling
- incoordination
- lack of fear of humans
- typically die after this - often from diaphragm muscle being paralyzed and can’t breathe anymore
Rabies Human Symptoms
- itching around bite and flu-like symptoms first
- muscle aches, dilated pupils
- hypersensitivity to light, sound, etc
- spasms, convulsions, inability to swallow (usually too late at this point)
- gradual paralysis until death from respiratory failure
Rabies Symptoms Onset
- Usually takes about 30-60 days in humans - huge advantage because you can watch the dog for 2 weeks to see if it has rabies, and you still have time to treat yourself
- Dogs - rarely more than 2 weeks before you see symptoms (but can go to 6 months)
Prevention when bitten
- If you are bitten, WASH well with soap and hot water (for 30-40 sec)
- Virus is very fragile and destroyed fairly easily
- Seek medical assistance
- Take note of what animal looked like - trap it if safely possible
Rabies testing in brain
- Test for it by removing brain - test for antibodies
- Don’t shoot animal in head bc you need it intact for testing
Laws and Rabies
- Must have dogs, cats, (ferrets) vaccinated
- No approved vaccine for wolf hybrids: can still vaccinate, but if it bites, it will be considered an unvaccinated animal
- Only vaccination by vet is accepted
Law: If bitten by 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
Law: If bitten by unvaccinated dog
- dog must be quarantined in a clinic for the 10 days or destroyed
Rabies cases
- in US 2021, 5 cases of rabies (all deaths) - at least 3 of them had been exposed to bats and ignored it
- 29 animal cases in WI in 2017
A 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
Rabies Exposure from Cows
Common exposure from cows
* cows bellow and appear to be choking
* first response of many farmers, vets is to reach in and check
* saliva is transferred into cuts, or they may scratch on teeth - wear gloves
Lyme Disease
Relatively new disease
* A bacterial disease (spirochete bacteria)
* Can cause arthritis, heart muscle inflammation, fever, shifting-leg lameness
* Also a problem in humans
* Vaccines are available (for dogs)
* Treatable with antibiotics, but difficult
Lyme Disease: Human stages
- Bulls eye shaped lesion (70-80%), flu-like symptoms, headaches, bodyaches
- Secondary lesions, facial palsy, disruption of heartbeat
- Centra; nervous disorder
Lyme Disease: deer tick
- most common vector is deer tick
- ticks often get it from small rodents
Pre-exposure prophylaxis
- antibodies made by bacteria
- hopes that it will last for a season
- still being worked on
Baylis ascaris (Roundworm)
- Roundworm found in raccoons
- Aberrant migration in humans - burrows into you
- Can travel to brain and eventually cause death
- Good to avoid raccoons and droppings as well
Baylis ascaris in WI
- About half of raccoons in WI are infected
- More common in southern WI than in north
West Nile Virus
- Fairly new to US - about 1999
- Transmitted by mosquitoes
- Less than 1% of people show severe symptoms
- About 20% show some symptoms
Where do mosquitoes get West Nile Virus?
From birds
How do you avoid West Nile Virus
Wear mosquito repellent
Psittacosis
- Bacterial, can usually treat it
- Birds
Tuberculosis
- Bacterial
- Antibiotic treatment - although there are some antibiotic resistant forms
Colibacillosis
- E. coli
- diarrhea, from food sources
Brucellosis (undulant fever)
- Can cause spontaneous abortions in animals
- In humans, causes sweating, fever, fatigue
- Usually contracted from consuiming unpasteurized or raw products of infected animal
Salmonellosis
- Food poisoning
- Eliminate problem by cooking
Avian/Swine Influenza
- Not typically zoonotic, but humans can get sick from these
