Medical Parasitology Flashcards
Define the following terms
- ANTHROPONOTIC
- ZOONOTIC
- VECTOR BORNE
- PRIMARY HOST
- Transmitted from human to human
- Transmitted from animal reservoir
- Transmitted by a carrier
- Site of parasitic sexual reproduction
What are the two classifications for parasites?
TROPICAL
TEMPERATE
What are the signs of pinworms?
Anal itching at night
Weight loss
Irritated skin
Describe cycle of infection for pinworms.
- Unintentional inhalation of pinworm eggs
- Remain in intestine until they mature
- Female pinworms lay eggs at anal skins causing itching
- Upon scratching, eggs can transfer to fingers
What is the main advice for pinworm infections?
- Regular handwashing
- Disinfect kitchen and bathroom surfaces
- Ensure children wear underwear at night
- Wash sleepwear, sheets, towels etc.
How is a pinworm infection diagnosed?
- Sellotape test - sticky end pressed against skin around anus
- Eggs stick to tape
What is the main treatment for pinworms?
- Mebendazole
- Initial dose followed by second dose 2-3 weeks later
- Ointment to soothe itching skin
What are whipworms?
- Eggs passed in faeces of infected persons
- Common in humid climates/areas with poor hygiene and sanitation
- Occurs in children
Define infection cycle of whipworms.
- Eggs hatch in small intestine and develop in its walls
- Thinner end burrows into large intestine
- Thicker end projects into lumen and mates with other worms
- Causes TDS - treated with albendazole
Define Trichomoniasis
- Protozoa
- Infects urogenital tracts
- Common STI
Describe Giardia lamblia
- Flagellated - colonises small intestine
- Ventral adhesive discs allows attachment to epithelium
- Reproduces via binary fission
- Remains confined to lumen of small intestine
Define cryptosporidium
- Chlorine resistant
- Linked to drinking and swimming in contaminated water
- Causes watery diarrhoea
Describe toxoplasma
- No obvious symptoms in adults
- May cause mild flu-like symptoms and eye problems
- Very severe in immunosuppressed patients
Give the two groups of human parasitic worms.
- FLATWORMS - Platyhelminths - separate into trematodes and cestodes
- ROUNDWORMS - Nematodes
Describe ascaris
- Infects oral-faecal route
- Eggs ingested causing release and migration of larvae
- Worms mature in upper GI
Describe hookworms.
- Eggs in faeces hatch
- Larvae mature and penetrate skin
- Develop in small intestine
Give an example of a condition caused by filariasis
ELEPHANTIASIS
Describe schistosomiasis
- Eggs in urine and faeces
- Migrate to urinary stem - damage to liver and bladder
Describe tapeworms.
- Larva in intermediate host
- Cause cyst formation
- Caused by eating undercooked meat
Describe hydatid disease.
- ZOONOTIC
- Eggs go to various sites and form hydatid cysts
- Can cause anaphylactic shock
Describe amoebic dysentery
- Caused by Entamoeba histolytica
- Intestinal infection
- Invasive - penetrates mucosa
What is the vector and reservoir for leishmaniasis?
VECTOR - Sandfly
RESERVOIR - Mammals
Describe trypanosomiasis
- Transmitted by tsetse fly
- Causes sores, fevers, haematuria, aching muscles
- PHASE 1 - intermittent bouts of fever
- PHASE 2 - neurological effects
Describe malaria transmission
- VECTOR - female Anopheles mosquito
- HOST - Humans
- Development of plasmodium antibodies providing partial immunity
- Carriers of sickle cell mutations provide partial resistance
What should be considered in malaria cases?
- Can present in multiple ways so often misdiagnosed
- Should always be considered in feverish patients who have recently travelled to endemic regions
