Parasitology Flashcards
blood borne parasitic diseases
malaria, babesia, ehrlichia and anaplsma, trypanomoma, leishmania
characteristics of parasitic diseases
high prevalance in developing countries, lower socioeconomic population, low mortality and morbidity, limited drug development, no vaccines (except malaria)
ectoparasite
parasite which lives on the outside of the host (infestation)
endoparasite
parasite which lives within the body of the host
direct life cycle
only humans are host, goes through infective stage like ovum, cyst, larva that is passed out of the body and infects another healthy person
indirect life cycle
multiple hosts required for life cycle development. definitive and intermediate host
parasitic protozoa
unicellular, includes: ameba, flagellates, ciliates, sporozoa
parasitic helminths
multicellular, includes: nematodes, cestodes, trematodes
Malaria
caused by single cell protozoan from Plasmodium genus. has 2 complete life cycles that occurs in the mosquito and human. transmitted to humans by female mosquito from genus anopheles.
fever, chills, headache, sweats, fatigue, nausea, vomiting
cold stage to hot stage to sweating stage
duffy antigen
absence of duffy antigen in RBC prevents Plasmodium vivax malaria
protection against malaria infection
no duffy antigen, sickle hemoglobin S and C, thalassemias
life cycle of malarial parasite
mosquito regurgitates stomach contents into human which introduces sporozites into bloodstream. This ends up in the liver which releases merozites to infect RBC.
plasmodium falciparum
can infect all ages of RBC, results in the appearance of PfEMP-1 protein on the surface of RBC. PfEMP-1 attaches to CD36 receptors on other cells. infected cells are stuck to organs and other tissues resulting in reduced number of circulating RBC and occlusion. Reduced oxygen to various parts of body.
Malaria vaccine
targets outer membrane protein of the early blood phase (circumsporozoite) of P. falciparum
Babesia
infects RBC. transmitted by ticks. malaria like symptoms
Anaplasma phagocytophilum
infects WBC. transmitted by ticks. malaria like symtoms
Chagas Disease
transmitted by triatomine insects (kissing bugs). can result in acute form (death) or chronic (asympotmatic for years)
Leishmaniasis
can be asymptomatic for years, transmitted by sandflies, obligate intracellular protozoa
cutaneous (chronic skin ulcers), mucocutaneous (lesions of the mouth, nose pharynx), visceral (fever, weight loss, anorexia, splenomegaly, hepatomegaly)
Protozoan (single celled) GI Parasites
E. histolytica, nonpathogenic entamoeba species, giardia lamblia, cryptosporidium parvum, trichonomonas vaginalis
E. histolytica
fecal-oral transmission, most people are asymptomatic, involves trophozites that live in the large intestine, can also infect liver and lung, profuse bloody diarrhea, hepatic disease, hepatic abscess
Giardiasis (beaver fever)
zoonosis (raccoon washes food in water that is ingested by humans), fecal oral transmission, travelers’ diarrhea
Cryptosporidium parvum
resistant to chlorination, destroyed by UV light, watery diarrhea, transmission via recreational water (pools)
Trichomonas vaginalis
STD that survives in the genital tract, site specific and cannot survive outside urogenital system
painful urination, inflammation, discharge with foul odor
Intestinal Nematodes (roundworms)
ascaris lumbricoides, trichuris trichiura (whipworm), enterobius vermicularis (pinworm), strongyloides stercoralis, ancylostoma duodenale (hookworm)
ascariasis
large worms whose eggs need to mature in environment, no direct transmission between humans, heavy infections can cause intestinal obstruction, blockage of bile ducts
trichuriasis
toxins produced by worm can result in rectal prolapse
ancylostomiasis (hookworm)
most people are asymptomatic, some may experience chronic abdominal pain and persistent eosinophilia
results in iron deficiency anemia and protein energy malnutrition from blood loss, can be transmitted directed between humans
enterobius vermicularis (pinworm)
common in young children, can be transmitted directed between humans
Intestinal Cestodes (tapeworms)
Taenia sagniata (beef) and Taenia solum (pork), Diphyllobothrium latum (fish)
obtained from each raw meat
