Parasitic Infections Flashcards
Define parasite.
An organism living in or on a host and dependent on the host for nutrition – causing damage
What is the difference between an endoparasite and an ectoparasite?
Endoparasite – exist INSIDE the host
Ectoparasite – exist on the host
What are the two groups of endoparasites?
Protozoa
Metazoa
State the classes of organisms within the two groups of endoparasites.
Protozoa Amoeba Coccidia Ciliates Flagellates Metazoa Roundworms Flatworms Flukes
Give some examples of amoeba.
Entamoeba histolytica
Entamoeba dispar
Give some examples of coccidia.
Plasmodium species
Toxoplasma
Cryptosporidium
Give an example of a ciliate.
Balantidium coli
Give some examples of flagellates.
Trypanosoma
Trichomonas
Giardia
Leishmania
What is the main difference between the two types of amoeba?
Entamoeba histolytica can cause invasive amoebiasis
Entamoeba dispar is a normal commensal of the GI tract
What is amoeba infection caused by?
Ingestion of mature cysts in food or water contaminated by faeces
How many nuclei are there in mature cysts?
4
What are the treatment options for amoebiasis?
Nitroimidazole derivatives (kills trophozoites but not the cysts) Parmomycine or Diloxanide Furoate
What are the five types of plasmodium that cause malaria?
Falciparum- most toxic Malariae Vivax Ovale Knowlesi
What are the two types of host for plasmodium?
Human
Female anopheles mosquito
What are the two stages of malaria in humans?
Liver
Blood
Describe the symptoms of malaria.
PAROXYSMAL (occurs every 4-8 hours) Fever Chills Headaches Vomiting Muscle pain
State some complications of malaria.
Severe anaemia (due to intravascular haemolysis) Cerebral malaria Liver failure Shock Pulmonary oedema Abnormally low blood sugar Kidney failure Swelling and rupturing of the spleen
What are the treatments for uncomplicated malaria?
Chloroquine
What is the treatment for severe malaria?
Artemisinin-based combination therapy
How is malaria diagnosed?
Blood film (+ Giemsa stain)
What are the routes of infection of toxoplasma gondii?
Eating undercooked meat of animals harbouring tissue cysts
Consuming food or water contaminated with cat faeces
Blood transfusion
Organ transplantation
Transplacentally from mother to foetus
Which group of patients are particularly vulnerable to toxoplasma infection?
Immunocompromised
What can toxoplasma infections cause in these immunocompromised individuals?
CNS disease
Brain lesions
Pneumonitis
Retinochoroiditis
What does cryptosporidium cause?
DIARRHOEA (mainly in the immunocompromised)
How is it treated?
Fluid rehydration
How are most diarrhoeal protozoal diseases diagnosed?
Stool examination
What are the reservoirs of balantidium coli?
Primates
Rodents
Pigs
What are the effects of balantidium coli infection in immunocompromised patients?
Persistent DIARRHOEA Dysentery Abdominal pain Vomiting Nausea
How can drinking water be cleared of ovoid giardia lamblia cysts?
Filtration
Ovoid cysts can survive standard chlorination procedures
What is the main symptom of giardiasis?
DIARRHOEA
How is giardia transmitted?
Faeco-oral
What are the acute symptoms of giardiasis?
Diarrhoea Greasy stools that tend to float Stomach or abdominal cramps Nausea/vomiting Dehydration