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MD1 SF3 - EXAM 2 > Introduction à la parasitologie médicale > Flashcards

Introduction à la parasitologie médicale Flashcards

(85 cards)

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1
Q

What is parasitology?

A

The study of infections directly or indirectly caused by parasites

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2
Q

What is a parasite?

A

organism that feeds exclusively at the expense of a host organism of a different species, either permanently or during a phase of its life cycle

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3
Q

What is parasitosis?

A

infestation with or disease caused by parasites.

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4
Q

What are the three different kinds of hosts?

A

Hôte définitif: parasite à l’état adulte

Hôte intermédiaire: parasite à l’état de larve

Hôte accidentel: parasitosis usually found in another species

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5
Q

What is a reservoir?

A

Organism in which parasites multiply between transmissions and infections

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6
Q

How are parasites a problem globally?

A

Omnipresent on our planet —> found in all climates

Important cause of morbidity and mortality

Affect extremely high number of people

ex: Geohelminths —> 1.5 billion people infected, 24% of global population

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7
Q

How are parasites acquired in Canada? (3 main causes of parasitosis)

A

Locally acquired

Immigrants from endemic locations

Travellers and tourism

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8
Q

What are the three main ways in which parasites can be transmitted?

A
  1. Fecal-oral (digestive)
  2. Direct and indirect contact including transcutaneous
  3. Vectors (ex: ticks, mosquitos, etc.)
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9
Q

How is intestinal parasitosis dx in a lab?

A

Microscopie —> méthode de référence

Feces is the specimen of choice (need 2-3 specimens for dx)

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10
Q

Why do you study selles fraiches?

A

Fast dx, evaluate “charge parasitaire”, evaluate motility of protozoa, detect mobile larvae

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11
Q

Why do you study selles fixées?

A

SAF-fixatives can be used (formol d’acétate de sodium) which allows for permanent colouration that helps with better visualization of Trophozoïtes and Kystes

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12
Q

How is cutaneous parasitosis dx?

A

Microscope and colourations

Clinic?

  • Aspect of lesions and anatomical localization
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13
Q

How is “parasitose profond” dx?

A

Specimen for microscopy if possible… if not:

  1. Medical imagery
  2. Serology
  3. Antigen detection
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14
Q

Eosinophils and parasitosis:

A

Type of WBC

Increased in blood during allergic rxns and certain parisitoses

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15
Q

When are eosinophils associated with parasitosis?

A

Severe infections

Infections plus profondes

Dissemination and migration of parasites

IN CUTANEOUS AND INTESTINAL PARASITOSIS —> NO EOSINOPHILS

The absence of eosinophils does not mean an absence of parasites

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16
Q

What are the two classification groups of parasites?

A
  1. Ectoparasites
  2. Endoparasites
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17
Q

What are ectoparasites?

A

Live on the surface of the body (skin, hair, nails, etc.)

Either insects and arachnids

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18
Q

What are the different kinds of insects (4) and arachnids (2) that are considered ectoparasites?

A
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19
Q

What are Sarcoptes scabei? —> SCABIES

A

Mite (human skin)

Omnipresent globally

300M new cases annually

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20
Q

Who is the most vulnerable? (scabies)

A

Lower socioeconomic classes

People living in overcrowded living conditions

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21
Q

How is it transmitted? (scabies)

A

Person to person contact (direct)

VERY CONTAGIOUS (outbreaks in hospitals very very possible)

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22
Q

How do they reproduce? (scabies)

A

Creusent des sillons sous la peau

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23
Q

What sites are affected by scabies?

A
  1. Wrists
  2. Interdigital grooves
  3. Navel
  4. Lower back
  5. Buttocks and genitals
  6. Underarms and breasts
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24
Q

What is the incubation period of scabies?

A

Around 2 months but shorter if been exposed before

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25
Sx associated with scabies:
Prurit cutané
26
Dx of scabies:
Microscopie sur raclures de peau
27
Tx of scabies:
Permethrin 5% (topical cream) or Ivermectin
28
What are endoparasites?
Parasites that live inside organism Deep tissues and organs (ex: lungs, intestines, brain, etc.)
29
What are the 4 main categories of endoparasites?
1. Protozoa 2. Helminthes (worms) 3. Chromistes 4. Microsporidies (fungi)
30
How are protozoa classified?
classified according to their mode of locomotion
31
What are the sub-classifications of amoebas?
32
What are Entamoeba hystolytica?
Intestinal parasite (amoeba) Found across the globe but mostly in tropical and subtropical regions in: Latin America, Africa, and Asia 2nd highest cause of death due to parasitosis: 40k - 100k deaths per year Infects 500M people a year —\> 50M with abscesses in liver
33
What are the two forms of Entamoeba hystolytica?
1. **Trophozoite** —\> active form 2. **Kyste** —\> dissemination (resistant in environment)
34
How are Entamoeba hystolytica transmitted?
Fecal-oral (contaminated food and water) and oro-genital sex
35
Incubation period of Entamoeba hystolytica:
Couple days to months —\> hepatic abscesses in 8-20 weeks
36
Sx of Entamoeba hystolytica:
90% of cases are asymptomatic **but if not... causes intestinal symptoms such as:** * Wide range of symptoms * Mild diarrhoea * Dysentery * Haemorrhagic or fulminant colitis
37
Dx of Entamoeba hystolytica:
Microscope of fresh or fixed faecal matter Antigenic detection PCR testing Serology —\> hepatic abscesses
38
Tx of Entamoeba hystolytica:
All cases are treated even in asymptomatic: **Asymptomatic:** * Luminal agents —\> work against kystes * Paromomycin x 7 days **Intestinal or extra-intestinal infections:** * Tissular agent —\> work against trophozoites * Metronidazole x 7-10 days followed by a luminal agent
39
What are the sub-classifications of flagellated?
40
What are Giardia lamblia?
Intestinal parasitosis Most frequently found in Canada and US but can be found globally **Prevalent in temperate climates**: 2-10% of adults and 25% of children **Tropical climates**: 50-80% are carriers
41
What are the two forms of Giardia?
**Trophozoite** —\> active form **Kyste** —\> dissemination (resistant in environment)
42
How is giardia transmitted?
Fecal-oral: contaminated food/water or just person to person
43
What is the reservoir for giardia?
Mostly in beavers
44
In developed countries... where is giardia most often found?
Daycare service Hikers HARSAH (hommes ayant des relations sexuelles avec d'autres hommes) Family members of a patient Immunosuppressed (IgA deficiency)
45
What is the incubation period of giardia?
7-14 days
46
Sx of giardia:
**small intestine** * Nausea and vomiting * Abdominal cramps * Diarrhea * Steatorrhea and odour * Flatulence **Symptoms last for 2-4 weeks but can turn chronic in some cases**
47
Dx of giardia:
Microscope: selle fixée or intestinal biopsy Antigen detection PCR test and serology
48
Tx of giardia:
Who is treated: **EVERYONE**, symptomatic and asymptomatic (to avoid transmission) **Metronidazole** x 5-7 days
49
What are the sub-classification of sporozoa?
50
What is Plasmodium sp.?
Malaria --\> paludism 200M cases a year —\> 80% of cases in 16 counties (15 in Sub-Saharan Africa and India)
51
What are the 5 species of plasmodium that infect humans?
1. P. **falciparum** (mondial) 2. P. **vivax** (pas d’Afrique Sub-saharienne 3. P. **ovale** (Afrique surtout) 4. P. **malariae** (mondial) 5. P. **knowlesi** (Borneo et Malaisie)
52
What are the 4 forms of plasmodium?
1. **Gametocytes** —\> germinative form, ingested by mosquitos 2. **Sporozoites** —\> form injected by mosquitos 3. **Schizont** —\> disseminated form 4. **Trophozoites** —\> mature form
53
How are plasmodium transmitted?
Through mosquitos **Vector —\> anophèle (genus of mosquito)** Mostly in rural regions during rainy season
54
What are the two cycles of plasmodium infection?
Hepatocytes (liver) Erythrocytes (blood)
55
What is the incubation of plasmodium?
8-25 days —\> fever up to 3 months after returning from trip
56
Sx of Plasmodium infection:
Fever and chills Sweating Headaches Weakness and discomfort Myalgia and arthralgia Diarrhoea (or constipation) and abdominal cramps
57
What causes a severe rxn to plasmodium?
**Especially P. falciparum (sometimes vivax)** **Causes:** * Neurological impairment * Severe hemorrhage * Respiratory distress **Risk factors:** * People that aren't immune * Children * Pregnant women * Immunosuppressed individuals
58
Dx of plasmodium infection:
Frottis sanguin —\> frottis mince, goutte épaisse Antigen detection **(rapid testing, best for P. falciparum and vivax)** Serology and PCR testing
59
Tx of plasmodium infection:
**Medical emergency!** **Depends on:** species, region where acquired, severity of infection **Rx available:** * Atovaquone-proguanil (Malarone ®) * Chloroquine * Mefloquine * Doxycicline * Primaquine **IF SEVERE INFECTION = Artesunate IV**
60
How can malaria be prevented?
* Traveller education * Protection against mosquitoes * Insect repellent (Deet 30%) * Light-coloured long garments * Mosquito nets * Limit activities outside from dusk to dawn * Drug prophylaxis
61
How are helminthes classified?
classified according to their morphology
62
What are the sub-classifications of nematodes?
ROUND WORMS
63
What are *Enterobius vermicularis*?
Pinworms (oxyure) Intestinal parasites **Global, but mostly in temperate climates in children between 5 and 10 years old**
64
What are the two main forms of pinworms?
Adult worm (8-13 mm) Eggs
65
How are pinworms transmitted?
**Females live 2 - 3 months** **Fecal-oral transmission:** * Contaminated food * Person to person * Self-infection **Indirect contact transmission:** * Clothing and bedding * Surfaces **Aerial transmission of eggs possible** **Frequent intra-family transmission**
66
What is the incubation period of pinworms?
1-2 months
67
Sx associated with pinworms:
Infections localized in cecum or appendix Can be asymptomatic or cause anal itching (prurit anal) * Excoriations * Possible bacterial superinfections * Night agitation and insomnia * **Digestive sx if infection is more severe**
68
Dx of pinworms:
Microscopie sur selles —\> not very useful **"Scotch Test" test à la cellophane adhésive de Graham** —\> morning, before shower/bath
69
Tx of pinworms:
**Antiparasitic with action against nematodes:** * Mebendazole * Albendazole * Pyrantel pamoate
70
What are the sub-classifications of cestodes?
Tapeworms
71
What are the two forms of tapeworm infections?
Humain hôte **définitif**: Vers matures, Infection **tractus digestif** Humain hôte **intermédiaire**: Larves, Infections **e****xtra-intestinales**e
72
What Is Taenia solium?
Taenia du porc Mostly in tropical and sub-tropical climates in rural/périurban zones \>\>\> cities **Very frequent cause of convulsions**
73
What are the three main forms of Taenia solium?
1. Eggs 2. Cysticerques (larvae) 3. Adult worms (2-7 m)
74
How is Taenia solium transmitted?
Fecal-oral transmission from consuming contaminated pork, person to person, or auto-infestation
75
Sx of Taenia solium infection:
**Neurocysticercose** Atteinte SNC ou oculaire SNC: parenchymateuse ou extra- paranchymateuse **Atteinte parenchymateuse** * Plus fréquente * Convulsion * Lésions kystiques ou rehaussantes
76
Dx of Taenia solium:
TDM or IRM cérébrale Serology Occular examination (everyone) Biopsy to confirm dx
77
Tx of Taenia solium:
**Symptomatic patients with variable cysts or degeneration are treated** **Combination therapy** of antiparasitics * Albendazole * Praziquantel Corticosteroids Anti-convulsants
78
What are the sub-classifications of trematodes?
79
What is the Schistosoma sp.?
200M people affected annually in 74 countries **S. mansoni**: Africa, Middle East, Asia, and Latin America **S. japonicum**: China, Southwest Asia, and Indonesia **S. haematobium**: Africa and the Middle East
80
What are the two forms of the Schistosoma sp.?
Eggs Adult worms (male and female)
81
How are Schistosoma transmitted?
Transcutaneous from contact with water (mostly in children)
82
What is the acute form of a Schistosoma infection?
**Katayama fever** Incubation: 2-12 weeks, first exposure Eosiniphilie Sx: fever, chills, myalgia, abdominal pain, diarrhea **Auto-résolutive**
83
What is the chronic form of a Schistosoma infection?
**Immune response directed towards migrating eggs** Intestinal infection —\> portal hypertension Bladder problems, lung damage, possible SNC infection
84
Dx of Schistosoma:
Lab testing (**eosinophilia**) Microscope to search for eggs in feces and urine Serology
85
Tx of Schistosoma:
**Everyone is treated** Praziquantel and corticosteroids

MD1 SF3 - EXAM 2 (12 decks)

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