Introduction to Parasites Flashcards
Define: Parasite
An organism that:
> Lives in/on a host
> Derives benefit
> Causes host injury
Define: Symbiosis
> Living together
Long term
Between two diff species
Define: Mutualism
Where both species benefit
Define: Commensalism
Where parasite benefits to no host injury.
Define: Definitive Host
Harbours adult parasite or reproducing parasite.
Define: Intermediate Host
Harbours larval or asexual parasite.
Define: Paratenic Host
Harbours non-developing parasite.
What can Parasites be classed into?
Protozoa or Helminths
What is the name for macro-parasites?
Helminths
What is the name for micro-parasites?
Protozoa
Protozoa can be divided into what 4 categories?
> Flagellates
Amoeboids
Sporozoa
Trypanosomes
Helminths can be divided into what 2 categories?
> Platyhelminths (flatworms)
> Nematodes (round worm) - Intestinal/Tissue
Platyhelminths (flatworms) can be divided into what 2 sub-categories?
> Cestodes (Tapeworm)
> Trematodes (Flukes)
What type of Protozoa is Guardia Lamblia?
Flagellate
What type of Protozoa is Toxoplasma?
Sporozoa
What type of Protozoa is Leishmania?
Trypanosome
What is a direct life cycle?
Only affects one species
What is an indirect life cycle?
More than one species, with a intermediate host.
What is a complex indirect life cycle?
More than one species, intermediate host and paratenic host.
What is Ascariasis?
A helminth- intestinal nematode. Caused by Ascaris Lumbricoides.
How much of the world pop is infected with Ascariasis?
1/7th world pop.
What is the prevalence of Ascariasis?
3-8 year olds.
What is the life cycle of Ascariasis?
Direct
What lung condition can Ascariasis cause?
Loeffler’s Syndrome
What are the symptoms of Loeffler’s syndrome (caused by Ascariasis)?
> Dry Cough > Wheeze > Haemoptysis > Dyspnoea > Eosinophilic pneumonitis
What are Albendazole and Benzimidazole used to treat?
Ascariasis
How do Albendazole and Benzimidazole work?
Prevent worm glucose absorption - starve it.
What is Schistosomiasis?
A fluke (type of helminth)
What disease results from Schistosomiasis infection?
Bilharzia.
What does Bilharzia disease cause?
Bladder cancer and liver disease.
What is the life cycle of Schistosomiasis?
Indirect
What is the intermediate host of schistosomiasis?
Snails.
What is the rash caused by Schistosomiasis?
Swimmer’s Itch
What is another word for Acute Schistosomiasis?
Katayama Fever
What is the Schistosomiasis form that causes urinary problem?
S.Haemotobium
What symptoms does S.Haemotobium cause?
Hint : Urinary
> Bladder Squamous cell carcinoma.
Haematuria
Bladder fibrosis/dysfunction
What effect does Schistosomiasis have on hepatic/intestinal?
> Portal hypertension
> Liver Cirrhosis
What is Praziquantel used to treat?
Schistosomiasis
How does Praziquantel work?
Increase ion permeability –> tetanic contraction –> detachment –> death.
What type of parasite causes Hyatid Disease?
Helminth –> Platyhelminth –> Cestode (Tapeworm)
What is the parasite that causes Hyatid Disease?
Echinococcus Sp.
What Echnicoccus causes cystic hyatid disease?
E. granulosus
What Echinococcus causes alveolar hyatid disease?
E. multicilocularis
What percentage of Hyatid cysts are in the lungs?
20%
What percentage of Hyatid cysts are in the liver?
70%
What are symptoms of Hyatid disease?
May be asymptomatic
What can Hyatid disease also cause?
Secondary bacterial infection
What does cyst rupture cause?
Hypersensitivity
What is Malaria caused by?
> P. Malariae
P. Falciparum
P. Oval
P. Vivax
What type of parasite is Malaria?
Protozoa - Sporozoan
What does Malaria do to RBC?
Cause them to rupture every 48-72 hrs.
What symptoms does burst RBC cause?
Fevers and Rigors.
Anaemia, bleeding & DIC.
What symptoms do Cerebral Malaria cause?
Confusion, Headache and coma.
Why does Malaria cause renal failure?
Hb into urine - RBC burst.
What causes Cryptosporidiosis?
Cryptosporidium parvum and hominis
What type of parasite is Cryptosporidium parvum/hominis?
Protozoa –> Sporozoa
What are the symptoms of Cryptosporidiosis?
Hint: Think GI
Watery diarrhoea w/ mucus (no blood).
- Bloating, cramps, nausea, vomiting
How long does Cryptosporidiosis incubate for?
2-10 days (usually 7)
How is Cryptosporidiosis spread?
> Human-human
> Animal-human
In whom is Cryptosporidiosis severe?
> Very old/young
> Immunocompromised
What does symptomatic treatment of Cryptosporidiosis involve?
> Rehydration
> Nitazoxanide
What does immunocompromised treatment of Cryptosporidiosis involve?
> Nitazoxanide
Paromomycin - kill parasite.
Octreotide (reduce cramps and frequency)