Zoonoses and food-borne diseases Flashcards
What should you do if you suspect and anthrax case?
Peripheral blood smear and stain with new methylene blue.
Notify the government and send sample to state lab.
What are the three forms of anthrax in humans?
How dangerous is it for humans?
Cutaneous - black ulcerative, not painful
Pulmonary
Gastrointestinal
More severe when untreated, can kill.
What steps should you take to control and prevent an anthrax outbreak? (6)
Notify gov Movement control PPE Bury deep in pit with lining. Vx Pest control (can pick up spores and translocate).
How is leptospirosis spread?
For the less common routes, what climate do these mostly occur?
Rodent urine or water most common. Other animals can carry different serovars like pigs, cattle and dogs. These other routes are more common in tropical areas.
What are the 3 serovars of leptosporidia that are unique to Australia?
Arborea
Australis
Topaz
What is the pathophysiology and the 2 types of infection for Lepto in humans?
Endothelial damage, can be icteric or anicteric.
Has two phases:
Bacteraemic - neuro and gastro signs
Immune or complicated - renal adn pulmonary issues.
How do you control and prevent spread of lepto? (5)
Vx with specific serovar (humans and livestock)
control sylvanic reservoirs (rats, feral pigs)
Treat water
Education
PPE
How can humans contract Psittacosis?
Inhalation of small particals from bird (faeces, dander, nasal secretions).
What are some human clinical signs of psittacosis?
Flu-like that progresses into pneumonia and pneumonitis.
If the bacteria localises into liver, heart of CNS then you will see respective CSx.
How do humans most commonly contract Bartonella?
Cat scratch.
Why does Bartonella seem to have a higher prevalence in shelters?
Cats fight more Have more fleas (vector) Live in higher density Dirtier environment Usually young cats (who are more susceptible).
What are the CSx of Bartonella in humans?
Painful and chronic lymphadentitis Fever Rash \+/- GIT signs Sequalae --> neuro
What is coxiella burnetii more commonly known as?
Q fever
What makes coxiella burnetii more of a concern in public heath?
Pleomorphic quality so can become more spore like and survive harsh environments (UV, temp, disinfectants and drying).
Can travel far distances in wind.
How can humans be infected by coxiella burnetii? (transmission pathways)
Any ruminant fluids (esp. amniotic fluids) Ixodes tick sp. Dog and cat secretions Aerosol and dust Clothing.
What are the CSx of Q-fever?
How can the disease progress if chronic?
Severe flu-like headache retro-ocular pain fever penumonitis. Chronic --> endocarditis or hepatic complications.
What are the best control and prevention strategies for coxiella burnetii?
PPE
Workplace design, operation design to reduce exposure and transmission
Vx
How is tuberculosis spread between people?
Fomites and oronasal material.
What diseases does Mycobacteria Bovis (M. Bovis) cause in cattle?
Tuberculosis
How was M. bovis eradicated in Aus?
Test and cull, injected with unactive bacterial cell wall, if saw swelling later –> cull.
What are some other diseases caused by mycobacteria?
non-tubercular mycobacteria (NTM)
M. avium ssp. paratuberculosis (MAP)
How does tuberculosis spread to humans from cattle?
Unpasturised milk (MAP survives pasturisation) Contaminated water
What human GIT disease is MAP associated with?
Crohn’s disease.
What are hosts of most concern in Aus for carrying ans spreading Brucellosis?
Cattle and feral pigs
What are human CSx of brucellosis?
What are some complications if it is chronic?
fever, septicaemia, fatigue, arthralgia, insomnia.
Chronic –> spondylosis, endocarditis or orchitis
What techniques were taken to eradicate brucella abortus? (Cattle)
Volunteer testing to identify infected and carriers
Vx to reduce prevalence
BTEC (gov organisation) of test and cull + surveillance of milk and meat.
What are some tips to control Brucella suis? (6)
Control feral pigs Educate pig hunters Don't take dogs, Vx dogs PPE Don't touch/let dog eat pig repro tissues Report incidences.
What are some zoonotic parasites that are carried by dogs?
Hook worm - ancylostoma caninum
Round worm - Toxocara canis and strongyloides stercoralis
How do humans contract hookworms and round worms from dogs? (three different parasites in total)
Eggs excreted from dogs in faeces
A. caninum –> cutaneous penetration
S. stercoralis –> cutaneous penetration
T. canis –> ingestion.
What are the health conditions associated with A. caninum in humans?
Itchy feet
Cutaneous larval migrans
Enosinophilic enteritis (pre-adult/non-patent worm at ileocolic junction)
How do you treat people who are infected with A. caninum?
Albendazole/Ivermectin +/- AM
Mechanical removal
What are the clinical signs of S. stercoralis in humans?
Cutaneous larval migrans
GIT signs including malabsorption
Respiratory form tracheal migration
Hyper-infection syndrome –> death.
Describe how hyper-infection syndrome develops?
Build-up of adults in SI, many auto-infection of larvae, which then migrate into other intestinal sites. This results in septicaemia, bronchopneumonia, hepatitis.
Can be fatal.
How do you treat hosts of S. stercoralis? When will it be impossible to completely uninfect?
Tx = ivermectin moxidectin.
When auto-infected migrating larvae develop the antihelmithics will never reach them.
What makes it difficult to control Toxocara canis in the environment?
Highly resistant, can survive years.
What are the clinical manifestations that occur in humans with Toxocara canis?
Occular larval migrans
Visceral larval migrans
Takes a years for these clinical signs to appear (1-8 yrs or more)
What are some general methods to decrease dog and cat zoonotic parasite spread? (7)
- Hygiene
- Remove dog faeces so eggs don’t hatch in to larvae
- Regular de-worming
- Control feral dog population
- Don’t lie on dog beaches
- Shoes
- Education
How do you control scabies?
Treat the dog! mites cannot survive on humans
How do you control Echinococcus granulosus?
Don’t let dogs eat offal
De-worm dogs
Hand and food hygiene (faecal oral transmission)
What are the clinical signs of Echinococcus granulosus in humans?
Slow growing mass in body (hydatid cyst)
CSx variable according to hydatid cyst location.
Anaphylaxis if cyst fluid leaks out
How is Echidnoccocus granulosus population still prevalent in Aus despite domestic dog control?
Sylvatic cycle (wildlife and feral dogs/dingoes).
How can you reduce occurance of Echinococcus granulosus in Aus?
Control sylvatic cycle (praziquantel bait?) Education in hygiene no offal to dogs Wash fruit and veggies De-worm with praziquantel.
What are some methods to prevent human infection of Toxoplasma Gondii? (6)
- Regularly clean litter trays (2x/day) so oocsyts doesnt develop
- Cook Paratenic host meat completely
- Don’t drink unpasturised milk
- Reduce cat contraction by keeping indoors and not feeding raw meat
- Wash vegetables before eating
- Hand hygiene
What are the possible clinical signs of people infected with Toxoplamsa gondii? (4)
- Mostly asymptomatic
- More severe in immunocompromised, can lead to death
- Pregnant women infected during 1st trimester –> 5% chance of placental transmission, increasing risk of abortion or CSx at birth or later in life.
- Pregnant women infected in 3rd trimester –> 80% chance placental transmission but less likely to affect baby.
What is the main reason why we see outbreak in water-borne protozoal zoonotic diseases?
Mismanagement of effluent.
What are the 2 major zoonotic protozoae that are water-borne?
Giardia
Cryptosporidium
What are some control methods to reduce the transmission of Giardia in humans?
Good sanitisation, esp in overcrowding areas and young
Treated drinking water
Hand hygiene after handling pets (reservoirs)
Which animal is considered a multiplying host for cryptosporidium?
Calves, only for ~4 weeks as it is a self limiting infection
Adult cattle do not shed.
What are the major causes for cryptosporidium outbreaks in Aus?
Children in public swimming pools
Water-borne - drinking water not properly treated/reinfected before consumption of water
What should you recommend as a veterinarian if a client calls about a bat in their backyard?
Don’t touch bat!
have pets come in contact with the bat, if so bring in to discuss possible treatments.
Advise them to call Biosecurity QLD.
If there has been human contact advise they call QLD health
How should you send bat sample off to be tested for ABLV?
Freeze entire bat before packing and sending to biosecurity QLD.
What are three viruses that use bats as vectors? in what manner are they spread to humans?
ABLV - Bite or scratch
Nipah virus (not in Aus) - directly to humans, via pigs or human-human, concentrated in urine.
Hendra - from urine ([Highest]) –> horse –> human
How can you control Hendra virus spread to humans?
Reduce horse contact with bats (cover water troughs, less trees that attract bats, put in stable at night)
Vaccinations
What are some possible reasons why there has been a sudden outbreak in the occurence of Nipah virus?
deforestation –> bats in closer contact to spill-over hosts
Combine fruit and pig farming
Intensive farming of pigs
Commercial trade of pigs –> spreading
How did SARS start and spread?
Wildlife meat trade (bat)
Aerosol spread was easy due to crowded market place and poor hygiene.
what was MERS Initial outbreak and transmission?
Bats –> camels –> humans
Aerosol, feed/water, human-human, fomites
What type of disease do flaviviruses and alphaviruses cause in humans?
Flavivirus –> encephalitis
Alphavirus –> arthritic disease
What are some CSx of Ross River Virus in humans (alphavirus)
Non-specific = fatigue, myalgia, polyarthritis , rash and fever.
How can you control Ross river virus?
Control arthropod populations (no stagnant water, insecticides)
Prevent transmission –> protective clothing and repellant.
Who are the natural hosts for Barmah forest virus and how is it spread to humans?
Macropods, +/- possums and birds
alphavirus that is an arbovirus.
Who are the 2 most common flaviviruses in Australia?
What are their epidemiological patterns?
Murray Valley encephalitis
Kunjin (type of west nile virus)
Mostly Northern tropical Aus, changing with climate change.
What zoonotic arboviruses can infect horses?
RRV
MRE
WNV (Kunjin)
Which animal hosts are responsible for maintaining Japanese encephalitis virus life cycle and which act as amplifying hosts?
Who are the dead-end hosts?
Water birds maintain it
Pigs amplify it.
Humans and horses = dead-end
How do you control Japanese encephalitis?
Vx people
Control arthropod populaitons
What CSx do you expect in people infected with Dengue virus (1st vs 2nd time infected)
1st –> non-specific febrile
2nd –> higher AB response leading to increased vascular permeability, see shock, and potentially DIC. Fatal if untreated.
What is the common pathophysiology or Richettsia infection?
Endothelial destruction, obligate intracellular organism
Murine Typhus - vector and transmission
X. cheopi (Rat flea) –> bite on mm or inhalation from flea faecal particles.
Scrub Typhus - vector and transmission. Preferred climate.
Leptotrombidium (Mite) –> bite human
Likes warmer months and shows seasonality
Name an emerging zoonotic richettsia disease that had a flea as a vector.
Animals that are part of this life cycle.
Cat flea spotted fever (also called cat flea typhus).
Dogs and cats; dogs have been found to have R. felis = dogs are reservoir hosts.
What are the three different types of Yersinia pestis infections? How do these types manifest?
Bubonic –> When flea bites. Also from cat bites sometimes.
Systemic –> enters circulatory system and LNs
Pulmonary –> when infected via airborne human-human.
What are the various forms of Tularemia (rabbit fever) in humans? How it is transmitted?
Skin ulcer Ulceroglandular Pneumonic Gastrointestinal Transmission = bacteria spread by tick bite, or from animals carrying it (rodents and native & domestic animals).
What bacteria causes glanders. What was the animal of major concern
Burkholderia mallei.
Frequently infected from horses with it.
What pseudomonad bacteria do humans and animals need to be careful of when there are floods? Is it considered zoonotic?
Burkholderia pseudomallei.
There has never been evidence of direct transmission from animals to humans but there is the possibility.
How is erysipelothrix rhusiopathiae spread to animals and humans?
Rats –> pigs and humans (braised skin)
pigs –> humans
Vaccine –> self jab (MLV)
What are the clinical signs of lyme disease (Borrelia burgdorferi)?
Target rash
fever, arthritis, neuro signs, cardio
Is there concern lyme disease is in Australia
There have never been reported incidences with Australian origin but similar bacteria has been isolated in echidnas but never in ticks.
Can animals be asymptomatic carriers of ringworm?
Yes
Are all dermatophytes zoonotic?
No,
Which animals are common transmitters of dermatophytes to humans?
Dogs and cats mostly
*Guinea pigs and horses can have trichophyton mentagrophytes.
What is the best method to Dx dermatophyte and sp.
Culture.
Can also do stick tape impressions and observe under microscope.
What are some control methods for dermatophytes?
Antifungal creams (if can’t lick spot, wash hands if touch)
shelter those that are at higher risk of contraction
control rodents
Improve hygiene
What is the worst system mycosis in terms of human health and zoonosis?
What diseases does it cause?
Why is it the worst?
Cryptococcosis –> Multifocal skin papules/ulcers, CNS lesions, pneumonia
Very difficult to treat.
How do you diagnose mycoses?
Histopathology
Micro exam of sputum/discharge
Culture (some fungus is ubiquitous however)
Serological
What are the three common zoonotic parapoxviruses?
Scabby mouth
Bovine papular stomatitis (BPS)
Pseudocowpox (same as BPS but in calves)
How do sheep get orf (scabby mouth)?
How do humans get it?
abrasion + contact. Also in humans + self-vaccinate
How do humans get pseudocowpox?
What are some methods to control contraction?
Abrasion on hands and touch cow teat.
Udder and equipment hygiene, management practices
How can people be infected with foot and mouth disease? is it common?
Infection –> abrasion, milk, needle stick
Rare and non-fatal
What are the three most pathogenic types of influenza virus based on their H and N proteins?
H1N1
H2N2
H2N3
What are the roles of H and N proteins on influenza viruses?
H –>Attachment and entry into cells
N –> Dispertion and transmission of daughter viruses.
What are the two proteins on pig tracheal mucosal cells that mean human and avian influenza viruses can attach to?
alpha2-3 (a2-3) = birds
a2-6 = humans
Are pigs always considered to be the mixing pot for new variants of influenza?
No, it is suspected that humans have acted as a ‘mixing pot’
How can humans become infected with influenza?
Human-human
Avian contact
swine contact
Meat can be contaminated and there is evidence of GIT infectivity and infection (enteric symptoms)
What can you do to control the spread of influenza?
Biosecurity
Reduce exposure to animals and infected people
Control outbreak with strategic vaccination and isolation
vaccines and PPE
Surveillance and response.
