Les Zoonoses Flashcards
What is prévalence?
all old and new cases of an illness
What is incidence?
only the new cases of an illnesses (shows the risk)
can cause epidemics if the incidence increases above what is normally found in a population
What is an epidemic called when its in animals?
Épizootie
What is an endemic?
(of a disease or condition) regularly found among particular people or in a certain area
In animals: enzootie
What is a zoonose?
Toute infection naturellement transmissible entre un animal et l’humain
Can be direct transmission of through a vector (water, food, insect)
What is an anthropozoonose?
une maladie ou infection qui se transmet naturellement des animaux vertébrés à l’être humain
What is a zooanthroponose?
maladie ou infection qui se transmet naturellement de l’homme aux animaux vertébrés
What infectious agents are responsible for zoonoses?
Bacteria, fungi, parasites, viruses, unconventional infectious agents (ex: prions —> Mad Cow disease)
What is a maladie infectieuse émergeante?
infection don’t l’incidence s’est accrue depuis les derniers 20 ans et qui menacent de continuer à s’accroître
Have practically quadruples since 1960 —> 20% caused by resistance to treatment, 60-70% are zoonoses
Maladies infectieuses émergeants are usually associated with what? (3 things)
- Évolution des microbes: virulence, résistance, adaptation à un nouvel hôte (franchir la “barrière des espèces”)
- Perturbations de l’environnement: habitat, climat, agriculture intensive
- Perturbations de l’hôte: age, immunosuppressed population
What is a primary host?
a host that naturally allows an infectious agent to multiply which aids in its transmission to another host
It’s an important reservoir for the disease
What is a secondary host?
un hôte qui héberge un agent infectieux de façon transitoire
sometimes required to assure the development/maturation of infectious agent to complete the infectious cycle
if not required… can work as occasional hosts or as reservoirs
What is a “terminal” host?
secondary host that is unable to transmit the infectious agent to a primary host which stops the propagation of the infectious cycle
usually humans in the case of emerging zoonoses
What is a reservoir?
Ecological system in which a zoonotic agent indefinitely survives
such as:
- secondary hosts, vectors, biotope (milieu de vie du pathogène)
What diseases are not considered zoonoses?
Malaria (Plasmodium faciparum), schistosomiase (snail fever), onchocercose
no longer considered zoonoses because humans are now the primary host necessary for their infectious cycle
the “barrière inter-espèce” was crossed a long time ago
Common diseases that are no longer zoonoses:
Started as zoonoses… now primarily through spread interhuman contact
COVID, diphtheria, influenza, certain forms of the common cold, measles, smallpox, HIV-AIDS, tuberculosis
Anamnesis for zoonoes?
VOLCANS
Voyages
Occupations
Loisirs
Contacts
Animaux
Nourriture
Sexe
Système touché par brucellose
blood
Agent infectieux de brucellose
Brucella sp.
Reservoir for brucellose
Bovines, ovines, caprins, canines
Transmission de brucellose
Direct contact, aerosol, food
Système touché par campylobactériose
intestines
Agent infectieux de campylobactériose
Campylobacter sp.
Reservoir de campylobactériose
birds
Transmission de campylobactériose
food (raw meat and milk)
Système touché par Fièvre Q
cardiovascular and respiratory
Agent infectieux du fièvre Q
Coxiella burnetii
Reservoir du fièvre Q
bovines, ovines, caprines, canines, felines
Transmission du fièvre Q
aerosol and direct contact
Système touché par Yersinia gastroenteritis:
intestines
Agent infectieux de Yersinia gastroenteritis:
Yersinia enterocolitica (psychotroph)
Reservoir du Yersinia gastroenteritis:
porcine, canines, felines
Transmission du Yersinia gastroenteritis:
food and feces
Système touché par leptospirose
kidneys, liver, SNC
Agent infectieux du leptospirose
Leptospira sp.
Reservoir du leptospirose
Mostly rats, bovines, and porcines
Transmission du leptospirose
direct contact, urine, water, bites
Système touché par listériose
blood, SNC, digestive
Agent infectieux du listériose
Listeria monocytogenes (psychrotroph)
Reservoir du listériose
divers
Transmission du listériose
food, water, direct contact
Système touché par “Maladie du hamburger” → E. coli gastroenteritis
Intestines, kidneys
Agent infectieux du “Maladie du hamburger” → E. coli gastroenteritis
Escherichia coli that produce shigatoxin (O157:H7 and some other serotypes)
Reservoir du “Maladie du hamburger” → E. coli gastroenteritis
Bovines
Transmission du “Maladie du hamburger” → E. coli gastroenteritis
food and feces
Systems touched of Lyme disease:
cutaneous, articulations, divers
Infectious agent that causes lyme disease
Borrelia burgdorferi
Reservoir for lyme disease
mice, rodents, deer
Mode of transmission of lyme disease
ticks
Système touché par salmonelle
intestines
Agent infectieux du salmonelle
Salmonella sp.
Reservoir du salmonelle
reptiles, mammals, poultry
Transmission du salmonelle
food
Système touché par tularemie
cutaneous, respiratory, blood, lymphatic, digestive
Agent infectieux du tularemie
Francisella tularensis
Reservoir du tularemie
rodents, hares, muskrat, canines
Transmission du tularemie
direct contact, food, insects/ticks, bites, water?
Système touché par babesia
blood
Agent infectieux du babesia
Babesia microti
Reservoir du babesia
mammals
Transmission du babesia
Ticks
Système touché par cryptospridose
intestines
Agent infectieux du cryptosporidose
Cryptosporidium sp. (cholorotolérant)
Reservoir du cryptosporidiose
bovines, ovines, cerfs
Mode de transmission du cryptosporidiose
feces and water
Système touché par giardia
intestines
Agent infectieux du giardia
Giardia lamblia (chlorotolérant)
Reservoir du giardia
beaver, rodents, bovines, cefs, canines, felines
Transmission du giardia
Water and feces
Système touché par la rage
SNC
Agent infectieux de la rage
Lyssavirus
Reservoir de la rage
canines, bats, felines, etc.
Transmission de la rage
Bites, saliva
Système touché par “Hantavirus pulmonary syndrome”
respiratoire
Agent infectieux du Hantavirus pulmonary syndrome:
Hantavirus
Reservoir du Hantavirus pulmonary syndrome:
rodents
Transmission du Hantavirus pulmonary syndrome:
feces and aerosol
Stats on “maladies à déclaration obligatoire” #1
Stats on “maladies à déclaration obligatoire” #2
Stats on “maladies à déclaration obligatoire” #3
Etiology and transmission of Lyme disease
Borrelia bugdoferi from 1975-1985 in Lyme, Connecticut
Spirochetes
3% infection risk after each tick bite but infection rate grows with the time the tick is attached (low <36 hours)
What is the principal reservoir of Lyme disease?
White footed mouse
What is the principal vector of Lyme disease?
Ixodes ticks
Cycle de vie des tiques:
Triphasique: oeufs —> 1. larva 2. nymphe 3. adult —> oeufs
What species of ticks are associated with Lyme disease?
Ixodes: Lyme, babesiosis, ehrlichiosis
How to remove ticks?
DO NOT use fingers or nails… remove with a sharp object like tweezers
Hold tick by its head (hard part) with the tweezer as close as possible to the skin
Pull vertically (lightly), without twisting or swuishing
Wash skin and hands once tick is removed
Place tick in hermetically sealed container and consult a doctor who can analyze the tick for presence of Lyme
What are the 3 stages of Lyme disease?
- Localized (précoce)
- Disséminé précoce
- Disséminé tardif
A “tardive/persistante/chronique” form is currently in discussion
Post-treatment sx are reported in 5-20% of pts
What is stage 1?
début de l’infection avant dissémination des bactéries
60-80% of pts have an expanding erythema migrans with nodule
What is stage 2?
Dissemination of bacteria through the blood —> couple days to 6 months after the initial bite
sometimes accompanied by systematic sx such as: fever, fatigue, localized adenopathies, atteinte cardiaque/neurologique (déficit moteur/sensitif)
What is stage 3?
Complication of preceding stage… appears months later
Usually leads to problems with articulations esp. arthritis of the knees
What is erythema migrans?
2-30 days after tick bite (usually 7-14)
2/3 pts develop these lesions that are generally asymptomatic and circular, oval, or triangular
Their size quickly increases up to a diameter > 5cm and are present for at least 48hr
Clinical manifestations, dx, tx, and prophylaxis of Lyme
Usually the “tableau clinique” isn’t enough to establish a dx… serology usually necessary (ELISA or IFA) and epidemiology of area must be looked at
Where do most cases of Lyme in Quebec come from?
Eastern Townships/Southern Quebec
2016: 179 cases, 70% acquired in Quebec → 60% Estrie, 30% Montérégie
2017: 328 cases, 76% acquired in Quebec → 85% in Estrie/Montérégie
2019: 500 cases, 76% acquired in Quebec
At risk population for Lyme:
People who live/work in areas with forests, high grass → moderate risk
Biking, walks in areas with known ticks
Rx used to treat Lyme:
Stades localisés/disséminés précoces: doxycycline or amoxicillin for 2-3 weeks
Disséminé tardif: ceftriaxone or penicillin for 4 weeks, arthritis can be treated with methotrexate or hydroxychloroquine
What preventative measures should be taken to protect yourself from ticks?
Avoid favourable habitats (shade, long grass)
Wear clothing that covers arms and legs
Using bug spray (DEET 30% > 12 ans, Icaridine 20% > 6 months)
Cutaneous exams and tick extraction
Can prescribe prophylactic ATBs if very high suspicion of bite from infected tick
Should prophylactic antibiotherapy be used?
Not usually recommended after tick bite in Quebec… can be used in cases of bites from zones where risk is higher in Quebec, or endemic zones in the US, Europe, or other parts of Canada
Lyme -> MADO?
LYME DISEASE HAS BEEN A MADO SINCE 2003 → MALADIE À DÉCLARATION OBLIGATOIRE but it is still under reported
Etiology and transmission of rabies
Lyssavirus
Can only be transmitted by mammals
What are the principal reservoirs of rabies?
Skunks, raccoons, bats (NA), foxes, DOGS!
How is rabies transmitted?
Contact with saliva, LCR, and nervous tissue, bites, scratches, possible aerosol transmission
Rabies on a global scale:
150 countries are affected by rabies
2000 → 55k people died of rabies
2015 → estimated to be around 59k
Where?
- Mostly in Asia and Africa, and in the Americas in Haiti
How has rabies been so well controlled in N.A?
Vaccination campaigns for dogs → “Zéro d’ici 2030” et “un monde, une santé”
Important to focus on vet services, public health, and education to prevent rabies
What are the clinical manifestations of a rabies infection?
Incubation for 5 days to 3 months… in some cases up to 2 years
- Phase prodrome: fever, headaches, malaise, irritability, anorexia (4-10 days)
- Later leads to agitation, snoring, confusion, paralysis, and muscular spasm
- and later convulsions and cardiac arrhythmia that lead to coma and death
Death usually occurs 2 to 10 days after first symptoms. Survival is almost unknown once symptoms have presented, even with intensive care
How is rabies dx?
Immunofluorescence directe (corps de Negri) sur les biopsies, RT-PCR is now the “méthode de choix”
What is hydrophobia?
Sx of rabies infection…
Mostly in humans.. fear of water → two forms
- Forme paralytique
- Forme furieuse
How to treat rabies post-exposition?
Treat plaies (clean) as soon as possible
Administer a series of doses of the rabies vaccine according to WHO
Administer antirabic immunoglobulin if indicated
Ideally all of these things must be done in the hours following contact
What are the three types of contact (vaccination criteria set by WHO)?
Type 1: contact with animal
- (pas d’exposition, pas d’intervention)
Type 2: mordillement de la peau nue, griffures ou égratignures superficielles sans saignement
- (traitement de la plaie, vaccination immédiate)
Type 3: morsures ou griffures uniques/multiples ayant traversé le derme, léchage sur peau lésée, contamination des muqueuses par la salive après léchage, exposition à des chauve-souris (contact+salive) →
- (traitement de la plaie, vaccination immédiate, administration d’immunoglobuline antirabique)
