Parasites Flashcards
What does eosinophilia indicate?
A rise in eosinophil count is sometimes the first sign that a patient is developing an allergy towards a drug e.g. penicillin or NSAIDs. Atopic diseases e.g. asthma, hayfever and eczema are the commonest causes in clinical practice.
What is the classification of parasites?
- Ectoparasites - parasites on the skin and hair
- Endoparasites - parasites on mucosal surfaces such as gut and in the tissue, can be divided into: helminths (worm-like, mostly visible to naked eye) and protozoan parasites (single-celled, eukaryotic organisms, usually motile)
What is a host?
Parasites may infect differential animals at different stages of their life cycle. The animal that hosts the adult stage of the parasite is known as the definitive host. The animal that hosts the developmental stage of a parasite is known as the intermediate or secondary host. An accidental host is a host that the parasite cannot use to complete its life cycle (dead end).
What is a vector?
Parasites that are capable of transmitting other diseases e.g. ticks transmit Lyme disease, mosquitos transmit malaria. They require a blood meal in order to reproduce and transmit malaria to humans in their saliva. Mosquitos are not a parasite because they do not attach themselves to the host for long periods of time.
What is resistant malaria?
- Doxycycline resistance is very rare and it is the recommended agent of chemoprophylaxis
- In contrast resistance to chloroquine is increasingly common
- Other drugs commonly used for chemo-prophylaxis are atovaquine and mefloquine
What are the symptoms of malaria?
- Headache
- Fever
- Fatigue and pain (especially back pain)
- Skin: chills and sweating
- Dry cough
- Splenomegaly
- N+v
What are examples of helminths?
- Pinworm: caused by Enterbills vermicularis and is a common helminthic infection in school-age children.
- Diphyllobothrium latum: or fish tape worm, caught by eating undercooked fish or sashimi.
Helminths cause eosinophilia
How does a pinworm work?
The adult worms live in the child’s gut, venturing out of anus of night to lat their egg’s on the perineum. The child scratches their itchy bottom and transmits the eggs to their own or another person’s mouth. The eggs are ingested and larvae hatch in the host and mature therefore completing the cycle of infection. The eggs can survive for several weeks on bedding. Even if asymptomatic, everyone in the same house as a patient infected with pinworm should be treated. If confirmation of the diagnosis is needed, sticky tape can be used to pick up eggs from the perineum and seen under a microscope.
What is toxoplasma gondii?
A common protozoan infection. Usually remains dormant but can reactivate in patients who are immunosuppressed e.g. patients who are immunosupressed, patients with advanced HIV causing brain abscesses and retinitis. Primary infection in pregnancy can be harmful to the foetus (TORCH microorganism). Kittens shed the cysts in their faeces hence the advice to pregnancy women not to clean litter trays.
What is toxoplasma gondii?
A common protozoan infection. Usually remains dormant but can reactivate in patients who are immunosuppressed e.g. patients who are immunosupressed, patients with advanced HIV causing brain abscesses and retinitis. Primary infection in pregnancy can be harmful to the foetus (TORCH microorganism). Kittens shed the cysts in their faeces hence the advice to pregnancy women not to clean litter trays.
What is toxoplasma gondii?
A common protozoan infection. Usually remains dormant but can reactivate in patients who are immunosuppressed e.g. patients who are immunosupressed, patients with advanced HIV causing brain abscesses and retinitis. Primary infection in pregnancy can be harmful to the foetus (TORCH microorganism). Kittens shed the cysts in their faeces hence the advice to pregnancy women not to clean litter trays.
What is toxoplasma gondii?
A common protozoan infection. Usually remains dormant but can reactivate in patients who are immunosuppressed e.g. patients who are immunosupressed, patients with advanced HIV causing brain abscesses and retinitis. Primary infection in pregnancy can be harmful to the foetus (TORCH microorganism). Kittens shed the cysts in their faeces hence the advice to pregnancy women not to clean litter trays.
What is giardia lamblia?
More common in low income countries, however can be acquired in the UK. It is spread by faecal-oral transmission from contaminated water or via person-to-person contact. The main symptom is watery diarrhoea and patients often complain of excessive flatulence. The symptoms can last for weeks without treatment and can sometimes cause malabsorption. The treatment for giardiasis is metronidazole or tinidazole.
What is cryptosporidium parvum?
Is another GI protozoa that causes watery diarrhoea. It mainly occurs in young children and immunocompromised patients.
What is trichomonas vaginalis?
An STI that causes vaginal and urethral discharge
