Zoonoses Flashcards
What is the WHO definition of a zoonosis?
A disease/infection which is transmitted naturally between vertebrate animals and humans
List 5 zoonoses transmitted by mice
Hantan viruses (fleas) Lyme borreliosis Ehrlichia Bartonella Lymphocytic choriomeningitis
List 7 zoonoses transmitted by rats
Rabies Leptospirosis Lassa fever Hantan viruses Plague Pasteruellosis Haverhill fever (rat bite)
List 7 zoonoses transmitted by cats
Bartonellosis (cat scratch) Leptospirosis Q-fever Toxoplasmosis Rabies Ringworm Toxocariasis
List 8 zoonoses transmitted by dogs
Hydatid disease Leptospirosis Brucellosis Q-fever Rabies MRSA Ringworm Toxocariasis
List 9 zoonoses transmitted by small ruminants (sheep and goats)
Anthrax Brucellosis Q-fever Cryptosporidiosis Enzootic abortion Louping ill Orff virus Rift valley fever Toxoplasmosis
List 9 zoonoses transmitted by cattle
Anthrax Leptospiriosis Brucella Bovine TB Anaplasmosis Toxoplasmosis E. coli 0157 Rift valley fever Ringworm
List 8 zoonoses transmitted by swine
Brucellosis Leptospirosis Erysipeloid Cysticerosis Trichinella HEV Influenza A Streptococcal sepsis
List 6 zoonoses transmitted by birds
Psitticosis Influenza Cryptococcus Influenza A Salmonella (poultry) West Nile fever (poultry)
List 7 water-sports associated zoonoses
Leptospirosis HAV Giardia Toxoplasmosis Mycobacterium marinum/ulcerans Burkholderia pseudomallei E. coli
List 4 water-borne zoonoses
Campylobacter
Salmonella
E. coli toxin (VTEC 0157)
Cryptosporidiosis
List 7 food-associated zoonoses
Listeria (cow-cheese-human) Taenia Cysticercosis Toxoplasmosis Trichinellosis Yersiniosis Giardia
Brucella - microscopic features
Gram-negative Aerobic Facultatively intracellular Endemic world wide Small Nonencapsulated Flagellated Coccobacilli
What is the name of the disease caused by brucella?
Brucellosis
Which 4 animals are associated with brucellosis?
Farm animals
Dogs
Cattle
Small ruminants
Swine
What are the 3 modes of transmission of brucellosis?
Inhalation
Skin contact
Mucus membrane contact
Ingestion
How is brucellosis contracted?
Consumption of contaminated food (untreated milk/dairy)
Animal contact
Environmental contamination
Laboratory acquired
List 6 symptoms of brucellosis
Undulant fever (peaks in evening, normal by morning) Malaise Rigors Sweating Myalgia/arthralgia Tiredness
What is the incubation period for brucellosis?
3-4 weeks
List 3 potential complications of brucellosis
Endocarditis
Osteomyelitis
Meningoencephalitis
List 6 signs of brucellosis
Arthritis Spinal tenderness Lymphadenopathy Splenomegaly Hepatomegaly Epididymo-orchitis
List 4 rare signs of brucellosis
Jaundice
CNS abnormalities
Cardiac murmur
Penumonia
What investigations are performed if brucellosis suspected, and what are the likely results?
Serology
- Anti-O polysaccharide antibody (titres >1:160)
FBC
- WCC normal
- Leukocytosis rare
- Significant number of pts neutropaenic
What is the treatment for brucellosis?
4-6 weeks of tetracycline or doxycycline AND stretomycin
OR
8 weeks of doxycycline AND rifampicin
What is the name of the pathogen that causes rabies?
Rhabdovirus
What are the 2 most common animal vectors of rabies?
Dogs and bats
How long does rhabdovirus take to migrate to the CNS?
Months - years
Without treatment, how does rabies progress?
Fatal encephalitis - death usually occurs within 2-10 days, survival rare once symptoms have presented
What is the name of the cerebral inclusions seen in brain samples that are pathognomonic for rabies?
Negri bodies
Give 3 features of the rabies prodrome
Fever
Headache
Sore throat
Which test can be used antemortem to detect the rabies antigen in brain tissue?
Indirect Fluorescent Antibody Test (IFA)
Other than IFA, name 2 other tests that can be used to diagnose rabies
Serological neutralisation test
ELISA, for specific IgM
What is the treatment for rabies?
Post exposure IgG
Recent experimental treatment (at symptomatic presentation): Milwaukee protocol. Successfully saved first patient in 2004. Involves induced coma, ketamine and antivirals.
What is the name of the bacteria responsible for bubonic plague?
Yersinia pestis
Yersinia pestis - microscopic features
Gram-negative
Lactose fermenter
Rod-shaped coccobacillus
Facultative anaerobe
Which animals are a source of yersinia pestis and how is it transmitted?
Rats
Transmitted by fleas
How is plague diagnosed?
PCR
How is bubonic plague contracted and how does it present?
Flea bites human
Presents with swollen lymph nodes (bubos) and dry gangrene
How does pulmonary plague differ from bubonic?
Spread person-person (rather than rat-flea-person)
This kind of plague seen during (relatively) more recent epidemics
What is the treatment for plague?
Streptomycin
Doxycycline
Gentamicin
Chloramphenicol (in meningitis)
Leptospira interrogans - microscopic features
Gram -ve
Spirochaete (spiral shaped)
Obligate aerobic
Motile
What is the name of the disease caused by Leptospira interrogans?
Leptospirosis
How is leptospirosis transmitted?
L. interrogans excreted in dog/rat urine
Penetrates broken skin when swimming in contaminated water
List 5 animal sources of leptospirosis
Rats Cats Dogs Cattle Swine
What is the incubation period for leptospirosis?
10-14 days
How does leptospirosis present?
High spiking fever Headache Conjunctival haemorrhages Jaundice Malaise Myalgia Meningism Carditis Renal failure Haemolytic anaemia
What is the treatment for leptospirosis?
Amoxicillin, erythromycin, doxycycline or ampicillin
What is the name of the bacteria that causes anthrax?
Bacillus anthracis
Bacillus anthracis - microscopic features
Obligate pathogen Gram-positive Endospore-forming Rod-shaped Can be grown in an ordinary nutrient medium under aerobic or anaerobic conditions
List 2 animal sources of anthrax
Cattle Small ruminants (sheep, goats)
How does cutaneous anthrax present?
Small black lesions with a rim of oedema
How does pulmonary anthrax present?
Massive lymphadenopathy
Mediastinal haemorrhage
Pleural effusion
Respiratory failure
What is another name for pulmonary anthrax?
Woolsorter’s disease
What is another name for Lyme disease?
Lyme borreliosis
What is the name of the bacterium that cause Lyme disease?
Borrelia burgdoferi (and other Borrelia spp)
Borrelia burgdoferi - microscopic features
Spirochaete Diderm (double-membrane) therefore neither gram positive nor negative Flat wave shape Anaerobic Motile Flagellated
How is Lyme disease transmitted?
Arthropod-borne, transmitted through tick (ixodes) bite. Ticks also transmit to other vertebrates eg mice
What are the symptoms of early localised Lyme disease?
Cyclical fevers
Non-specific flu-like symptoms
Erythema chronicum migrans (ECM) - “Bullseye rash”
How does early disseminated Lyme disease present?
Malaise Lymphadenopathy Hepatitis Carditis Arthritis
How does late persistent Lyme disease present?
Arthritis
Focal neuropathy
Neuropsychiatric disturbance
Acrodermatitis chronic atrophicans (ACA)
How is Lyme disease diagnosed?
Biopsy of the edge of the bullseye rash
ELISA for Lyme antibodies
What is the treatment for Lyme disease?
Doxycycline for 2-3 weeks (alternatively amoxicillin, cephalosporins)
If CNS issues: IV ceftriaxone for 2-4 weeks
What is a potential consequence following treatment for Lyme disease?
ME type symptoms
Which bacterium causes Q fever?
Coxiella burnetii
Coxiella burnetii - microscopic features
Obligate intracellular
Gram-negative
Highly resistant to environmental stresses
Biphasic developmental cycle
What is the treatment for Q fever?
Doxycycline
Which other respiratory disease might Q fever be mistaken for?
Atypical pneumonia
How does Q fever present?
Symptoms begin 2-5 weeks post infection Fever Dry cough Fatigue Pleural effusion Diarrhoea NO rash
Does Q fever cause a rash?
No
List 4 animal sources of Q fever
Cattle
Sheep
Dogs
Cats
Which pathogens cause Leishmaniosis?
Protozoan parasites of the genus Leishmania
How is the Leishmania parasite transmitted?
Via the bite of certain types of sandflies (South and Central America, Middle East)
Which 2 Leishmania species cause cutaneous Leishmaniosis?
L. major
L. tropica
How does cutaneous Leishmaniosis present?
Skin ulcer at site of bite (due to multiplication of dermal macrophages)
Heals after 1 year leaving depigmented scar
May be single/multiple painless nodules which grow and ulcerate
What type of hypersensitivity reaction is cutaneous Leishmaniosis?
Type IV
How many types of Leishmaniosis exist, and what are they?
4 types
Cutaneous
Diffuse cutaneous
Muco-cutaneous
Visceral
Which patients are more likely to get diffuse cutaneous Leishmaniosis?
Immunodeficient
How does diffuse cutaneous Leishmoniosis present?
Nodular skin lesions that do NOT ulcerate
Lots of nodules, esp on nose
Skin test -ve (due to immunodeficiency)
Which Leishmania species causes muco-cutaneous Leishmaniosis?
L. braziliensis
How does muco-cutaneous leishmaniosis present?
Dermal ulcer same as cutaneous leishmaniosis
Months/years later: ulcers in mucous membranes of nose and mouth
What is visceral leishmaniosis also known as?
Kala Azar
Black fever
Dumdum fever
Which 2 species of leishmania cause visceral leishmaniosis?
L. donovani
L. infantum
L. chagasi (South America)
Which patients are more likely to get visceral leishmaniosis?
Young, malnourished children
How does visceral leishmaniosis present?
Abdo discomfort
Distension
Anorexia
Weight loss
What specific pathology is caused by L. donovani?
Invasion of the reticuloendothelial system
Causes hepatosplenomegaly and BM invasion
Later results in disfiguring dermal disease, post kala-azar dermal leishmaniasis (PKDL)
