parasites - lecture 35 Flashcards
(48 cards)
1
Q
Protozoan parasites-General features
A
- Unicellular
- parasitic (acquire nutrition from the host )
- asexual and sexual
2
Q
what are the location and common routes if parasites
A
- intestinal : faecal oral
- urogenital: sexual transmission
- Blood and tissue : insect vectors
3
Q
what’s the life cycle of a protozoa
A
-cysts - inactive and in the environment
-Trophozoite - metabolically active
- Intestinal parasites grow and divide within the bowel and are passed into the
environment.
they may be trophozoites and cysts
4
Q
Cyst or oocytes
A
- passed in feces
- Non motile
- Resistand to hostile environment
- does not multiply
5
Q
Trophozoite
A
- Metabolically active
- Motile
- Multiplies by replication
6
Q
Name the intestinal protozoas
A
- Entamoeba histolytica
- Balantidium coli
- Giardia lamblia
- Cryptosporidium parvum
- Cyclospora cyatenensis
7
Q
Name a urogential protozal parasite
A
-Trichomonas vaginalis
8
Q
Entamoeba histolytica
A
- Pseudopodia
- causes bloody diarrhoea (amoebic dysentery)
- amoebic liver abscess
- asexually
9
Q
Balantidium coli:
A
- ciliate
- found in pigs colon
- produces colonic ulceration
- asexually reproduces
10
Q
Giardia lamblia
A
- flagellate
-lives in the
small intestine - malabsorption
-reproduces asexually
11
Q
Cryptosporidium parvum
A
-non-motile
-prevalent in the
immunocompromised
-reproduces asexually and sexually
12
Q
Cyclospora cyatenensis
A
- non-motile
- parasitizes the small intestinal mucosa
- diarrhoea
- asexually and sexually
13
Q
Trichomonas vaginalis
A
flagellate, urogenital parasite, sexually transmitted,
reproduces asexually
14
Q
Name the extra-intesitanal/blood and tissue protozoa
A
- Plasmodium spp
- Leishmania spp
- Trypanosoma
15
Q
Plasmodium spp
A
-Anopheles
mosquito
-Malaria
16
Q
Leishmania spp
A
- flagellate
- sand flies
17
Q
African Trypanosoma
A
- sleeping sickness
- Tsetse fly
18
Q
American Trypanosoma
A
- Chagas disease
- Reduviid/Triamtomine
19
Q
Name 2 Pathogenic free-living amoebae
A
- Naegleria fowleri
- Acanthamoeba spp.-
20
Q
Naegleria fowler
A
- freshwater
-Invasion
from nasal mucosa into the brain
-meningoencephalitis
21
Q
Acanthamoeba spp
A
- soil and water
- lens liquid gets contaminated or comes from dust or swimming
- causes keratitis
22
Q
Metazoan parasites-General features
A
-Eukaryotic multicellular animals that have digestive, circulatory, nervous, excretory and reproductive systems -bilateral symmetry -reproduce sexually and asexually -
23
Q
Classified Helminths are called :
A
➢ Nemathelminthes (roundworms)-Nematoda
➢ Platyhelminthes (flatworms)-Trematoda and Cestoda
24
Q
what are the infective forms of nematodes
A
- egg
- filariform larvae
- 3rd stage larvae
25
what are the infective forms of trematodes
- cercaria
| - metacercaria
26
what are the infective forms
- proglottid
- embryonated egg
- cysticercus
- cystericercoid
27
Presence of worms might result in:
➢Mechanical blockage
➢Pressure from the growing parasite
➢Nutritional deficiency
28
Significance of Polyparasitism
| multiparasitism or co-infection
• High numbers of infections: increases chance of >1 parasite
29
Symptoms associated with nematode infections
Lungs (larvae):
➢Asthma or pneumonia-like
➢Cough, shortness of breath, wheezing.
Intestines (adult worms):
➢Diarrhea; or bloody stools
➢General GI symptoms: nausea, vomiting, abdominal pain.
➢Severe infections: malnutrition, weight loss.
30
Nematodes (round worms)- General features
- cyndrical bodies
- complete digestive tracts
- body covered in cuticle
- hooks or suckers
- male and female sexes
- the worms produce eggs
31
Ascaris
- roundworm
- poor hygiene
- adult worm lives in small intestine
32
• Enterobius
pinworm
Fecal-oral
➢Prevalent worldwide
➢Found mainly in children
33
Trichuris
whipworm
-fecal-oral route
-diarrhoea, rectal prolapse
and anaemia
34
• Ancylostoma & Necator
hookworm
-Acquired by skin penetration, a major
cause of anaemia in the tropics
35
Strongyloides
```
threadworm
➢Acquired by skin penetration,
inhabits the small bowel
➢Infection more severe in
immunocompromized people
```
36
Trichinella
pork roundworm
Encysted larvae occur in striate
muscle and symptoms occur based
on location
37
Toxocara
```
dog/cat roundworm
-embryonated eggs are ingested
from dog or cat faeces present in
soil
➢It is common in children and can
cause visceral larva migrans (VLM)
```
38
Lymphatic filariae
```
➢Wuchereria
➢Brugia
Microfilarial nematodes transmitted by
mosquito and fly and causative agents of
lymphatic filariasis
```
39
Cutaneous filariae
```
➢Onchocerca
➢Loa loa
➢Dracunculus
➢Microfilarial nematodes transmitted by
mosquito and fly and cause visual
impairment, blindness and severe itching
of the skin in infected individuals
```
40
what are the 3 stages of nematodes
- egg
- larva(splits into molt)
- adult
41
Trematodes (flukes)-General features
-dead end digestive system (same opening )
-life cycle involves more than one host
-
42
Fasciolopsis buski (intestinal fluke)
-pigs
-inflammation in chronic infection
-ulceration and
haemorrhage small intestine
43
Paragonimus westermani (lung fluke)
This parasite is acquired by ingestion of infective
| metacercariae in raw or pickled crustaceans
44
• Fasciola hepatica (liver fluke)
A parasite of sheep, humans become infected when ingest
freshwater plants, parasite lives in the intra-hepatic bile
ducts of the liver. Fascioliasis can lead to severe anaemia in
humans
45
• Clonorchis sinensis (Chinese liver fluke)
➢ Acquired by ingestion of infective metacercariae in raw,
| pickled, smoked fish
46
Cestodes (tapeworms)-General features
```
-Flat segments called proglottids
develop sequentially from a head
called the scolex.
-no digestive tract
-
```
47
• Taenia saginata (beef tapeworm) and Taenia
| solium (pork tapeworm
```
➢ causes cysticercosis worldwide
➢ acquired by ingestion of contaminated,
uncooked beef and pork that contain
cystercerci
➢ Taenia solium causes neurocysticercosi
```
48
```
• Echinococcus granulosus (dog tapeworm) and
Echinococcus multilocularis (rodent tapeworm)
```
➢ Hydatid disease occurs when the larval
stages of these organisms are ingested
➢ The larvae may develop in the human host
and cause lesions in several organs
