Dit document bevat alle slides van alle hoorcolleges, aangevuld met aantekeningen tijdens het hc, welke niet op de slides stonden. Kortom, een document wat de hele cursus omvat!
LECTURES PARASITOLOGY
LECTURE 1: CLASSIFICATION, LIFE CYCLES AND DEFINITIONS
DEFINITIONS
Parasites: Eukaryotic organisms that have to live in or on other organisms to complete their natural life cycle
Medical parasitology: Eukaryotic organisms that infect humans hosts
SYMBIOSIS
Symbiosis: Organisms living together. Close association between two organisms; (Micro)organisms and host.
- Commensalism: ‘eating at the same table’
o Benefit is uni-directional → Microorganism benefits, host is neither harmed nor helped.
- Mutualism:
o Benefit is bi-directional → Microorganism and host benefit.
- Parasitism:
o Benefit is uni-directional → Microorganism benefits, host is harmed
TYPE OF PARASITES
ENDO- VS ECTOPARASITES
- Endoparasites: Live IN the host → infection
o Protozoa (unicellular eukaryotes):
▪ Size: 1-100 uM
▪ Intra- or extracellular
▪ Sexual or asexual reproduction in host → binary fission of schizogony
▪ Increase parasite load
▪ Classification based on movement organelles and type of reproduction
▪ Types:
• Rhizopods
• Cilliates
• Flagellates
• Sporozoans
o Metazoa (multicellular):
▪ Size: mm – meters
▪ Hermaphroditic or males and females
▪ Reproduction: Eggs or larvae
▪ Stable population
▪ Classification based on morphology, sex and digestive tract
▪ Types:
• Trematodes (flukes)
• Cestodes (tapeworms) → Flat worms and hermaphroditic (they can still
produce off-spring with only one egg)
• Nematodes (roundworms)
- Ectoparasites: Live ON the host → infestation
o Insecta (lice, fleas)
o Arachnida (mites, ticks)
,OBLIGATE VS FACULTATIVE PARASITES
- Obligate: The parasite cannot survive without its host.
- Facultative: The parasite may exist in a free living state.
TYPE OF HOSTS
- Definitive host: In which sexual reproduction takes place, that is, the fertilization process.
o Two gametes form a zygote. This is preceded by sexual multiplication/gametogony
(formation of gametes). If in a host only sexual multiplication takes place (such as in malaria)
and not fertilization, it’s not a definitive host but an intermediate host.
o Sexual multiplication and fertilization are two distinct processes in sexual reproduction.
- Intermediate host: In which asexual reproduction takes place.
- Accidental host: Parasite is seldom found in this host (host was infected by accident)
o These hosts are often a dead end and the lifecycle stops here. In these hosts, often disease is
caused which is neither beneficial for the hosts nor the parasite as disease can cause death.
LIFE CYCLES
- Direct: Parasite needs only one host to complete its life cycle.
o Enterobius vermicularis
▪ Fecal-oral auto-infection.
- Indirect: Parasite needs two (or more) hosts to complete its life cycle (often an intermediate and
definitive host)
o T. saginata and solium
▪ Humans definitive host
▪ Fecal-oral auto-infection is possible
,LECTURE 2: DIAGNOSTIC CHALLENGES IN PARASITOLOGY
Lecture clips:
INTRODUCTION DIAGNOSTIC RESEARCH
PROTOZOA
Characteristics of protozoa
- single cell organism; 1-100 µm
o microscope needed to see
- intra/extra cellular
- multiply within host
- schizogony/sporogony or binary fission
Lifestyle and reproduction:
Plasmodium: schizogony →
Intestinal protozoa, like Entamoeba/Giardia: 2 stages:
- Trophozoites: moving around, causes morbidity
o Vegetative; motile, feeding
o asexual reproduction
o disintegrate → difficult to detect
- Cyst formation: dormant stage
o decreased metabolism; rounding, external cell wall
o resistance to environment => transmission of infection
HELMINTHS
Characteristics of helminths
- mm to meters
- multi cellular adult stage
- multiple organs
Lifecycle and reproduction
Adult worms: hermaphrodite or separate sex
- egg or larvae production
- eggs/larvae leave the host
- stable population => reflection of morbidity?
- Chronic disease
o depending on species adult worm 1 year => several decades
o the more worms, the more disease
Clinical aspects: Cryptosporidium parvum/ C. hominis
- Endemic in Netherlands (children)
- Water related outbreaks → summer outbreaks
- Gastro-intestinal complaints chronic diarrhoea
- Self limiting in healthy individuals
- Severe in non-immono competent
- Detection of Oocyst via acid fast staining
Microscopy diagnosis of diarrhoea causing protozoa
- Cysts and trophozoites can be found in faeces
- Trophozoites cannot survive in environment → disintegrate within an hour
o Mix stool with fixative → will still be visible
Specific problem microscopic diagnosis of E. histolytica
- Entamoeba hystolica and dispar not morpholically distinguishable
- Dispar causes no diarrhoea
- Only histolytica can go into red blood cells: hematophagous → differentiate from dispar
Microscopy
- Advantages:
o Available
o Affordable
o Specificity (not for E. histolytica)
- Disadvantages:
o Sensitivity!!!!: Day to day variation in parasites → 3 different samples from 3 different days
o Specificity for E. histolytica
o Staining procedures
Antibody detection (serology)
- Advantages:
o Fast
Voordelen van het kopen van samenvattingen bij Stuvia op een rij:
Verzekerd van kwaliteit door reviews
Stuvia-klanten hebben meer dan 700.000 samenvattingen beoordeeld. Zo weet je zeker dat je de beste documenten koopt!
Snel en makkelijk kopen
Je betaalt supersnel en eenmalig met iDeal, creditcard of Stuvia-tegoed voor de samenvatting. Zonder lidmaatschap.
Focus op de essentie
Samenvattingen worden geschreven voor en door anderen. Daarom zijn de samenvattingen altijd betrouwbaar en actueel. Zo kom je snel tot de kern!
Veelgestelde vragen
Wat krijg ik als ik dit document koop?
Je krijgt een PDF, die direct beschikbaar is na je aankoop. Het gekochte document is altijd, overal en oneindig toegankelijk via je profiel.
Tevredenheidsgarantie: hoe werkt dat?
Onze tevredenheidsgarantie zorgt ervoor dat je altijd een studiedocument vindt dat goed bij je past. Je vult een formulier in en onze klantenservice regelt de rest.
Van wie koop ik deze samenvatting?
Stuvia is een marktplaats, je koop dit document dus niet van ons, maar van verkoper quintylisa18. Stuvia faciliteert de betaling aan de verkoper.
Zit ik meteen vast aan een abonnement?
Nee, je koopt alleen deze samenvatting voor €6,00. Je zit daarna nergens aan vast.
