Parasitology Flashcards
DALY
daily adjusted life year- helps calculate the global burden of disease (GBD) - non-monetary measure
takes into account: 1 the number of life years lost due to premature death 2 the number of healthy life years lost due to living with disability.
Trypanosoma Cruzi
Chagas Disease, Vector: Triatomid(kissing Blood) is nocturnal, Blood transfustions, Congenital transmission, Laboratory transmission, organ transplants. Treatment Benznidazole and nifurtimox.
Control- education, screening (esp children) improved housing, Vector control, screening of blood donors. NO VACCINE
Leishmania spp
Vector- Sand fly, Lutzomyia spp new world, Phlebotomus spp old world. amstigotes are converted to promastigotes in salivary glands of fly and this is what infects you. promastigotes are taken up by macrophates where they turn itno amastigotes. after 48 hours of binary fission the cells bursts. these white blood cells enter new skin and become cutaneous leishmaniasis and in 4-6 days move to organs and become visceral leishmanisasis( leishmania donovani complex
Diagnosis- spleen or bone marrow aspirate that show amstigotes, can also use a rK39 dipstick test in the field. Early Kala-Azar clincial symptoms. Irregular fever, anemia, leucopenia, diarrhoea, bleeding gums, joint pain, weight loss. Later symptoms Splenomegaly, hepatomegaly
–Treatment- Amphiteracin B\ Sodium Stibogluconate\ Paromomycin \ Miltefosine
–control- Screening (rK39) treatment of infected, insecticides.
Trichomonas vaginalis
Diagnosis- Direct characterisitic Trophozoites smear inpouch 3 day culture, Aptima TV, Molecular test.
- -Transmission- sexual intercourse.
- -clinical symptoms- vaginitis burining sensation, thick yellow discharge, vulvar or vagnial erythema. males often asymptomatic.
- -Treatment Metronidazole (flagyl) sexual partners treated simultaneously
Giardia Lamblia, intestinalis, duodenale
traveller’s Diarrhea
- -transmission- through hosts feces to fingers, flies, fields, fluids. This goes into our food and into us. mostly waterborne pathogen. the trophozite when it is in the body is not infective. The infective part has a cyst wall and is in a normal stool, diarrhea has the trophzoites passed.
- -diagnosis- all chronic diarrheas, unexplained weight loss, unresponding malnutrition, malabsorption syndrome. Stool miscropy, has a low sensitivity with sporadic shedding of cysts. Elisa antigen test, Immunofluorescent test (is expensive but highly sensitive/specific. as alast resort simply treat it and the dramatic improvement my be only diagnosis.
- -symptoms-pale loose stools fouls smelling, 3-8 times per day, abdominal distension, offensive flatulence, abdominal pain, weight loss, anorexia, Sulphorous bleching. (occaionally malabsoroption syndrome esp in malnourished children. )
- -Pathogenesis- severity depends on number of organisms, virulence of strain, host immunity mucosal damage secondary bacterial colonization.
- groups at risk- immunosuppressed, sewage workers, crowded institutions, cities, daycare centers, travelers.
- -Treatment- Metronidazole(Flagyl) Tinidazole (tindamax (USA)
Cryptosporidium Parvum
Clinical Signs- Explosive, brwon green watery Diarrhea 1-2 weeks after exposure, fever, vomiting, anorexia, abdominal discomfort. will resolve in a day to couple of weeks if immunocompetent.. Immunodeficient is life threatening malabsorption villous atropy
Site of infection- Enterocytes in gut.
Transmission- oocysts in stool is an environmental, foodborne, and waterborne pathogen.
Diagnosis- Oocysts in stool using a modified zielneelsen stain, Elisa, Immunofluorescent test
Treatment- none except supportive therapy.
Entamoeba Histolytica
Amoebiasis-
- -clinical signs- intestinal- amoebic dysnetery, invasive- amoebic liver abscesses( fever, tender liver, epigastric pain, hepatomegaly. 95% are asymptomatic- diarrhea insonsistent with gradual onset, no fever, flatulence, abdominal pain, 12x per day, blood and mucus in stool, trophozoites excreted, no significant malaise, tear drop ulcers in gut.
- -Diagnosis- cysts in stool Trophozoites in RBC’s (invasive form). Elisa Ag test- for abscess, direct aspiration and microscopic examination of trophozoites, Indirect use ultrasound, xray, CT , MRI
- -Treatment- Metronidazole (flagyl) followed by paromomycin(Humatin). for amoebic abscesses, chemotherapy with metronidazole or ultrasound guided drainage.
Toxoplasma Gondii
–transmission
through cats,bradyzoites in rodents/ birds or tachyzoites in raw milke–> shed unsporulated oocysts. Sporulation in environment takes 1-5 days(survive 1 year) and becomes oocyst then sporocyst then sporozoites. Oocyst transmitted thorugh contaminated water and environment.
can get bradyzoites from lamb goat, pork meat or lamb goat milk.
Tachyzoites are transported around the body in leukocytes and all tissues may be infected
–clinical signs, immuno-competent individuals are usually asymptomatic and have a life long immunity.
the bradyzoite has no inflammatory changes around cyst. mother infecting baby can have hydrocephalus and chorioretinitis with cognitive and visual impairment.
diagnosis, use imaging, igG and IgM derology elevated IgG indicates lifelong immunity
–people at risk- those who eat undercooked meat lamb goat or pork, cat owners, abattoir workers, butchers, veterinarians, children who eat soil.
–Treatment- for mothers who become IgM during pregnancy, spiramycin
Plasmodium falciparum
has two stages
–Transmission- by Anopheles. Starts out as gametocyte in the red blood cell–> mosquito–> Microgamete–>macrogamete–>zygote–>mosquito midgut –> oocyst–> bursting cyst–> sporozoites in salivary gland–> humans–> hepatic cell–> hypnozoite–> merozoites released from a mature liver schizont–> to erythrocyte–> tropnozoite–Erythorcytic schizont –> RBC–> gametocyte.
8-Days development in liver merozoites are released, 2 days or 2 cycles of replication in the blood you will see clinical symptoms and gametocytes = infective.
Diagnosis–> resembles flu, fever, anemia hepatosplenomegaly, in endemic areas follow transmission patterns and age. Direct tests –> PCR to detect nucleic acids, Rapid tests to detect parasite antigen, parasites in blood smear. thick and thin smears. – gametocytes are banana shaped. Many Trophs in 1 RBC
Clinical features Continuous fever, anemia hepatospleno megaly, are related to the development cycle of the parasite within the RBC, causes microcirculatory arrest. will cause renal failure, jaundice and fever, pulmonary edema, vomiting diarrhea, delirium stupor disorientation coma convulsions.
cerebral malaria, severe manifestions any reduction of consciousness should be suspect. Schizonts adhere to endothelial endthelium of the brain. dysconjugate gaze, retinal hemorages.
pregnant women more attractive can have vertical transmission.
–Treatment- Quinine/quinadine, arthemether\lumafantrine (coartem)
control
–Control- ITN screened bedrom knock down insecticide, insecticide vaporizers, repellent DEET, protective clothing.
Schistosoma spp
trematoda- causes bladder cancer. has ategument that protect themselves from immune response and is the place where they absorb everything.
transmission-adult lays egg in host where it comes out as a miracidia, the miricidia enters snail and becomes sporocyst, it then becomes cercaria and leaves the snail to enter the definitive host. . you will get a swimmers itch and they go to the liver where they meet and will go to venous plexus for hemotonium and the masnoic plexus for mansoni and jamoincum which are passed in the feces. the infected people have the adults female produces eggs and the eggs are characteristically shaped, they get into the water and then the snails. these eggs pass out maximamlly in the middle of the day.
Fasciola hepatica
trematoda, bile duct
Transmission-adult lays egg in host where it comes out as a miracidia, the miricidia enters snail and becomes sporocyst, it then becomes cercaria and leaves the snail to enter grass and becomes metacercaria, which then enters the definitive host where it becomes an adult. .
Clonorchis spp
Trematoda- bile duct, causes bile duct cancer.
Transmission-adult lays egg in host where it comes out as a miracidia, the miricidia enters snail and becomes sporocyst, it then becomes cercaria and leaves the snail to enter fish and becomes metacercaria, which then enters the definitive host where it becomes an adult.
Paragonimus spp
trematoda, lungs
Transmission-adult lays egg in host where it comes out as a miracidia, the miricidia enters snail and becomes sporocyst, it then becomes cercaria and leaves the snail to enter crab and becomes metacercaria, which then enters the definitive host where it becomes an adult.
Nifurtimox/Benznidazole
For Trypanosoma trypomastigoes, not effective against amastigotes. screening is only effective during the acute phase of infection.
Suramin, Elfornithine, Melarsoprol
Suramin and Eflornithine take care of Trypansoma gambiense and rhodiense everywher but the CNS. Melarsoprol crosses teh blood brain barrier and takes care of it in the CSF
Amphiteracin B\ Sodium Stibogluconate\ Paromomycin \ Miltefosine
treatment for Leishamania Tropica, donovani, braziliense
Paromycin also used with amoebas.
Metronidazole\ Tinidazole
Metronidazole- trichonomas vaginalis, giardia, Amoeba Tinidazole- Tindamax- USA)
Quinine\ quinidine\chloroquine\primaquine \artemether \ lumenfantrine \ atovaquone and proguanil \ melfoquine
quinine quinadine- destroys all bood stages, no resistance so is a reserve drug.
–chloroquine- used to treat P. Malariae, ovale, vivax to destroy all blood stages. used as prophylaxis causes itchy skin.
–Primaquine- destroys hypnozoites in liver.
–Arthemether/lumefantrine (coartem)- used to treat falciparum but shows resistance.
–Mefloquine(lariam) used as prophylaxis for p. falciparum side effect of neuropsychiatric problems
–Atovaquone and proguanil (malarone) used as a prophylaxis for p. falciparum.
Pauladrine- used as prophylaxis to malaria, causes mouth ulcers.
