Unit 3: Parasites Condensed Flashcards
(27 cards)
What is the difference between direct and indirect parasitic life cycles?
In direct, only humans are the host. In indirect, there are multiple hosts/involvement of vectors
Amebas, Flagellates, Ciliates, and Sporozoa are examples of what type of parasite?
Protoza (unicellular)
Nematodes (roundworms) and Cestodes (flatworms/tapeworms) are examples of what type of parasite?
Helminthes (multicellular)
Malaria, Babesia, Trypanosomes, Leishmania, and Filarial infections are all examples of what type of parasite?
Blood borne parasites
What parasite is currently most responsible and most lethal for Malaria?
Plasmodium falciparum (replaced P. vivax)
Thalassemias, G6PD, HbS, HbC, and Duffy antigen negativity are all examples of what?
Protective against malaria infection (Duffy antigen is a receptor on RBC so lacking it protects you!)
What are the 3 stages of malaria symptoms?
Cold stage, Hot stage, Sweating stage
What are the symptoms of the cold stage of malaria, WHEN does it occur?
Feeling of intense cold, vigorous shivering, lasts 15-60 minutes. Occurs PRIOR to RBC burst!
What are the symptoms of the hot stage, when does it occur?
Feelings of intense heat, dry burning skin, throbbing headache, lasts 2-6 hours. Occurs DURING the RBC burst, merozoites circulation.
What are the symptoms of the sweating stage, when does it occur?
Profuse sweating, declining temperature, exhausted and weak/sleepy, lasts 2-4 hours. It occurs while the RBCs are becoming infected.
What is special about p. falciparum and RBCs?
It is able to affect all ages of RBCs
Why might the parasetemia load in malaria seem low and why is this a problem?
Secondary antigen (PfEMP-1) appears on infected red cells, attach to CD36 receptors on endothelium/organs, so infected cells don’t circulate! –> OCCLUSION, can get CEREBRAL MALARIA, can infect the PLACENTA
B. microti, reservoir = mouse, vector = same tick as lyme disease! Get hemolytic anemia, nonspecific flu like symptoms (like malaria but the person didn’t go to a malaria area)
Babesia (US form)
92% in upper/eastern US, same tick as Lyme disease. Symptoms look just like babesia/malaria (fever, headache, muscle pain) can be serious illness/fatal if not treated correctly
Anaplasma Pagocytophilum (Human granulocytotropic anaplasmosis) aka Anaplasmosis
Parasite trypanosoma cruzi. Transmitted by blood sucking Reduvid bug in US, Tetse fly in Africa. Bug bites you, you scratch –> disseminate. Acute phase (swelling) and chronic phase, which may persist for life asymptomatically until dramatic cardiac/CNS/colon issues!
CHECK A PERSON’S EYES FOR BITES! (easiest to penetrate)
American Trypanosmoiasis: Chagas Disease
Vector = Sandflies, obligate intracellular protozoa! Multiplication occurs in histiocytes, but infected people are asymptomatic for a while. The infection is in the neutrophils! Look at the LESION!
Can have 3 types: cutaneous, muccocutaneous, or visceral leishmaniasis
Leishmaniasis
Found in the US, fecal oral transmission. Most people are asymptomatic though. Causes pseudomembranous colitis –> cysts in stools, also bloody diarrhea. In bad cases, can migrate up the peritoneum and infect liver/lung.
Amebiasis/E. histolytica
Cysts contaminate water supply, or human:human transmission. Most common cause of travelers’ diarrhea, see intermittent presentation of profuse watery diarrhea/asymptomatic. Poo eventually gets greasy/bad smelling because of malabsorption in the gut.
Giardiasis (Beaver Fever!)
Extremely resistant to chlorination in drinking water, likes water parks. Can be destroyed with UV light. Get watery diarrhea, dehydration, weight loss, abdom. pain, fever, nausea, vomiting. Can go into an asymptomatic phase but still be shedding cysts. In an immunocompetent person, symptoms are 1-2 weeks.
Cryptosporidium parvum
think P for pool!
Transmitted primarily through sex, can’t survive outside the UG tract. Incubation period, then as it multiples you get symptoms: vaginal discharge and smell. Women can go into asymptomatic phase after symptoms, or the chronic phase. Men can get prostate inflammation!
Trichomonas Vaginalis
Nematode. Most common helminthic infection. White/pink adult worms in SI and each female worm produces 200k+ eggs, but they only become infective on soil (so NO DIRECT TRANSMISSION), can get intestinal blockage and go into the lungs.
Ascariasis lumbricoides
Nematode. Infection results in ingestion of eggs from soil. Asymptomatic people who have worms may have peripheral eosinophilia. If you get hyper infection though–> inflamed mucosa, edematous and friable. Young kids can get rectal prolapse
Trichuriasis (Human whipworm)
Nematode. Penetrates foot and moves up. 1/4 of the world is infected. Low prevalence of infection still exists in the south b/c of outhouses. Can get IDA and malnutrition because of gradual blood loss.
Ankylostomiasis (Hook worm)
Nematode. Asymptomatic except for perianal area is itchy/burning! This is because the infectious eggs are laid here at night, so the scotch tape test is how to diagnosis it. It’s highly infective and you can get self infection from touching infective hands to mouth. Little kids.
Enterobius Vermicularis (Pinworm)
