Parasitic Infection Flashcards
What is an organism that lives on or in a host organism and gets its food from or at the expense of its host.
Parasite
What are the 3 main classes of human parasites?
- protozoa
- helminths
- ectoparasites.
What is a One-celled organisms that are free-living or harbors on a host.
Capable of multiplying in humans, contributing to it survival and permitting further serious infections to develop.
Protozoa
How is protozoa transmitted?
- Protozoa that harbor in human GI track are transmitted via fecal-oral route through contaminated food or water, or person-to-person contact.
- Protozoa in the blood or tissue are transmitted to another human by the bite of an infected arthropod vector.
How are protozoa classified into groups?
Protozoa are classified further into groups based on mode of movement.
- Sarcodina – The ameba (eg. Entamoeba)
- Mastigophora – The flagellates (eg. Giardia, Leishmania)
- Ciliophora – The cilates (eg. Balantidium; the only cilates protozoan to affect humans)
- Sporozoa – Non motile adult stage organisms (eg. Plasmodium, Cryptosporidium). *Cryptosporidium is the leading cause of waterborne disease in the US.
Large multicellular organisms visible to the naked eye in adult stage, that are free-living or harbors on a host
Helminths
What type of Parasite that invades the GI track, but unable to multiply in humans.
Helminths
How are helminths categorized
they are categorized into three main groups of soil-transmitted helminths human parasite infection.
- Flatworms (platyhelminths) – Reside in the GI tract. eg. Blood flukes (known as trematodes; eg. shisthosomiasis), and tapeworms (cestodes).
- Thorny-headed worms (acanthocephalins) – Reside in the GI tract.
- Roundworms (nematodes) – Reside in the GI tract, blood, lymph system or subcutaneous tissues (ie. ascarids, hookworms, pinworms).
- Ticks, fleas, lice, and mites that burrow into the skin and remain there for weeks to months. This category broadly including other blood-sucking arthropods such as mosquitos.
- Causes various disease, and more importantly functions as vectors or transmitters of many different pathogens that causes morbidity and mortality.
Ectoparasites
Labs/Rads/Dx diagnostic studies for parasitic infections
- Fecal (stool) exam
- Endoscopy/Colonoscopy
- Blood tests
- X-ray, Magnetic Resonance Imaging MRI
What lab is ordered to find protozoan or helminths parasite in patients presenting with GI symptoms indicative of parasitic infection
Fecal (stool) exam
How many samples of stool should be collected for a fecal (stool) exam
Collect three or more stool samples on separate days.
What is Used when stool exam findings are unremarkable, but patient continue to have symptoms indicative of GI parasitic infection.
Endoscopy/Colonoscopy
What are blood tests looking for when testing for parasites
- Serology looks for antibodies or parasite antigens produce by the body’s immune response to a parasitic disease.
- Blood smear identifies parasitic species in the blood under a microscope (eg. Malaria).
Why would x-ray/MRI be used for patient’s with parasites
Helps identify parasitic disease affecting certain organs.
What is parasitic treatment based on?
Treatment is base on the affected organ (ie. GI, Derm, blood, liver), symptoms, specific parasite, and other disease secondary from parasite.
Some drugs used to treat parasitic diseases are not approved (licensed) by the U.S. Food and Drug Administration (FDA) for sale in the US since their demand in this country is so low and seeking approval is not cost effective for the drug manufacturers
Some drugs are FDA permitted under an Investigational New Drug (IND) application such as
Artesunate, Diethycarbamazine, Melarsoprol, Suramin
How do you prevent parasitic infection
- preplanning travel
- proper clothing & treatment
- proper hygiene & handwashing
- proper food preparation
- eating from approved source
- insect repellants
- taking prophylaxis medication
- immunizations
- risk mitigation, crew education, appropriate PPE use
- early identification and treatment.
What is the disposition of a patient with parasitic infection
Disposition is based on infectious agent, and severity of illness
