Viruses and Eukaryotes for Step, non in INF Flashcards
Cryptosporidium (not tested on in INF)
auses diarrhea in immunocompromised patients (HIV)
Unicellular partially acid fast (only parasites that do this) organisms that can complete their entire life cycle within an animal. Infection is transmitted via infectious cysts in stool. Each cyst is composed of 4 motile sporozoites waiting to be released. These then attach to intestinal wall, causing the diarrhea symptoms and small intestine damage
Treatment: Nitazoxanide. You can also filter water to remove oocysts from potentialy threatening water. Spiramycin can also be used (macrolide antibiotic, and is not FDA approved in the US). Keep fluid and electrolyte balance
Dracuncuus medinensis, Onchocerca volvulus, Wuchereria bancrofti, Toxocara canis, Loa loa (non tested on in INF)
Dracunculus medinensis
Caused by drinking contaminated water containing copepods (tiny crustaceans) which contain larvae.
Diagnosis: adult females emerging from painful ulcers in the skin. Will also have eosinophilia
Treatment: extracting the worms. Can also treat with metronidazol.
Onchocerca volvulus
Causes hyper and hypo-pigmented spots (onchodermatitis). If it reaches the eye, may cause blindless (microfilariae getting there). Will also present with eosinophilia.
Diagnosis: Microfilariae seen in skin biopsy under microscope
Treatment: Ivermectin
Wuchereria bancrofti
Causes elephantiasis (long standing lymphedema), LAD, and cough from microfilariae that cause Type I hypersensitivity reaction.
Mosquitos carry it, deposit larvae on the skin, larvae penetrate the skin and enter the lymphatics, produce microfilariae
Diagnosis: thick blood smear to see the organisms, causes eosinophilia
Treatment: diethylcarbamazine
Toxocara canis
Spread via contamination of food from dog or cat feces. What is unique of these is that they never mature out of the larvae stage in the human and continue to circulate throughout the body, which can go on for years (why the name of the disease is Visceral Larva Migrans, if in the eye called Ocular Larva Migrans). Also presents with eosinophilia
Treatment: Albendazole
Loa loa (African Eye Worm)
Transmitted by deer flies. Worms migrate through subcutaneous tissue and causes transient angioedema (Calibar swellings). Adult worm can migrate to the eye and can be seen crawling in the conjunctiva
Diagnosis: Micofilariae seen on blood smear. Also causes eosinophilia
Treatment: diethylcarbamazine, albendazole
HHV6 - Roseola virus (Not tested on for INF exam)
Member of the Herpes virus, so it is a DNA virus and enveloped
Infects CD4 cells, so it has the potential to cause immunosuppression
Symptoms (causes Exanthema subitem): Generally presenting between 6 months - 2 years of age. See high fever for 3-4 days and followed by a diffuse maculo rash, often characterized by a lacy appearance that spares the face. Fever can be very high, leading to febrile seizures (104F)
Treatment: no treatment, simply supportive care
