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79 Cards in this Set

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Intestinal Amebas - what do you mention ?
Entameba Histolytica, Giardia Lamblia, Cryptosporidium Parvum
What 2 forms of Entameba Histolytica are there ? where are they found ?
Motile Tropohzoite and nonmotile Cyst.
Tropohozites predominate in diarrheal stools, cysts in hard stool.
How man nuclei do cysts of Antameba Histolytica have ? What is the life cycle ?
Cysts have 4 nculei. Life cycle : Ingestion of cysts from contaminated water/food, Cysts differentiate into trophozoites in the ileum --> colonization of the colon --> invasion into portal circulation --> abscess containing tropohozoites in liver
Entameba Histolytica : how many stool samples should you check ? how do you recognize their cysts/trophozoites ?
Check at least 3 stool samples. Tropohozites : small central nucleulos, fine chromatin granules. Cysts are small with 4 nuclei
2 tests for Antameba histolytica, also, what is the tx for active disease, what is the tx for cyst carriers ?
Tests : 1.Iodine stained wet mount, 2.Serology (indirect hemagglutinin assay). Tx for active : Metronidazole, for cyst carriers - iodoquinol
Giardia Lamblia : Life cycle. Also - what are the clinical symptoms
Cysts are ingested, give rise to two trophozites during excystation in the duodenum. Tropohozites attach to mucosa but do not invade.
Cliniacl : Due to fat and protein malabsorption --> nonbloody diarrhea, anorxia, cramps.
Give 3 tests for dx of Giardia Lamblia. What is the treatment ?
1. Finding tropohozoites or cysts in diarrhea, or finding cysts in formed stools, 2.ELISA for cyst wall antigen, 3.string test - trophozoites adhere to it.
Tx - Metronidazole
How do you get rid of cysts of Intestinal protozoa such as Entameba histolytica or Giardia lamblia ?
Filtration - chlorination does not kill them
How many nuclei do cysts and tropohozoites of Giardia lamblia have ? What is the shape of the tropohozoite ?
Cysts have 4 nuclei, tropohozoites have 2. Trophozoites are pear shaped.
What forms of Trichomonas vaginalis are there ? what is the structure ? What organs does it infect ? Is it common ?
Forms - only trophozoites, strucutre is cntral nucleus with 4 anterior flagella. Infects the vagina and prostate. Very common - 25-50% of women in US
Clinical symptoms of Giardia Lamblia, lab test, treatment
Symptoms - greenish vaginal discharge with itching. Test - Wet mount of vaginal or prostatic discharge --> pear shaped tropohzoite with jerky motion. Tx -Metronidazole for both partners
What are trypanosoma and Leishmania ? What are the species of trypanosoma ?
They are protozoa. Species of trypanosoma : T.Cruzii, T.Gambiense, T.Rhodesiense
What does Trypanosoma Cruzii cause ? What is its life cycle ?
It causes Chagas disease. Life-cycle : Vector- reduviid bug, reservoir-humans, cats, dogs, rats.
Ingestion of trypomastigotes by the bug --> epimastigotes-->trypomastigotes-->bug bites and delivers trypomastigotes which enter the persons blood-->form amastigotes within host cells(myocardial, RES cells)-->trypomastigotes--> taken again by the bug
What are the clinical symptoms of Chagas disease ? What forms are found in acute, what in chronic ?
T.cruzii amastigotes can kill cells. Acute - facial edema and a nodule at bite site, fever, lymphadenopathy. Chronic - myocarditis, megacolon.
In acute disease - trypomastigotes and amastigotes. In chronic - only amastigotes
Give 3 tests for T.Cruzii, what is the tx
Tests : 1.blood smears for motiile organisms, 2.xenodiagnosis, 3.serology (indirect hemagglutinin). Tx - Acute stage - nifurtimox
What do Trypanosoma Gambiense and Rhodesiense cause ? What is the vector, what is the reservoir ? What is the life cycle ?
They cause Sleeping sickness. Vector - Tsetse fly. Reservoir - Gambiense : humans, Rhodesiense - cattle, wild animals. Life-cycle :
Ingestion of trypomastigotes from a reservoir-->multiply in tsetse gut -->migrate to salivary glands and transform to Epimastigotes-->metacyclic trypomastigotes-->transmitted to host via bite-->blood-form trypomastigotes. Note lack of Amastigotes phase !
What is special about Trypanosoma Gambiense and Rhodesiense ?
What are the clinical symptoms ?
Special - they exhibit antigenic variations, roughly every 10 days. Clinical: Gambiense --> lowgrade chronic course over years, Rhodesiense - more acute progressive disease, fatal in months. 1.indurated skin ulcer, 2.Fever, lymphadenopathy, 3.Encephalitis, 4.Coma
Give 2 tests for T.Gambiesiense and Rhodesiense Sleeping sickness, What is the tx
Tests : 1.Blood smear - trypomastigotes, 2.ELISA for IgM.
Tx - if before encephalitis : Suramin
If after - Suramin + Melarsoprol
Which species does the genus Leishmania include ?, What disease does Leishmania Donovani cause ? What is the vector, and what is the reservoir of Donovani ?
species : Leishmania Donovani, L.Tropica, Mexicana, Braziliensis. Donovani causes Kala-Azar (visceral Leishmaniasis). Vector of Donovani is the sandfly, reservoirs are rodents, dogs, etc
What is the life-cycle of Leishmania Donovani ? Which cells are infected ?
Ingestion of mac's containing amastigotes by the female sandfly-->freed amastigotes differentiate into promastigotes-->migrate to sandfly pharynx -->transmitted by bite-->engulfed by macs of the host-->transform into amastigotes-->mac's die and release amastigotes that infect more cells.
Cells infected are RES cells.
What are the clinical symptoms of Kala-Azar (Leishmania Donovani), also - 2 tests. What is the treatment ?
Symptoms :Fever, weight loss -->splenomegaly-->hyperpigmentation-->anemia, leukopenia, thrombocytopenia-->secondary infections-->death.
Tests : 1.Detecting amastigotes in BM, spleen biopsies, 2.Serology (IgG).
Tx - Stibogluconate
Which disease do Leishmania Tropica and Mexica cause ? Leishmania Brazilensis ? What is the vector, what is the reservoir ? What is the life cycle ?
Tropica & Mexica - Cutaneous leishmaniosis, Brazilensis - Mucocutaneous, Vector- Sandfly, Reservoir - rodents. Life-cycle same as Leishmania Donovani
What is the clinical picture of cutaneous leishmania ? Of Mucocutaneous ? What is the dx, what is the tx ?
Cutaneous - Red papule at bite site -->satellite nodules-->caolesce and ulcerate. Mucocutaneous - papule at bite site -->metastatic lesions form --> granulomas and ulcerating lesions destroy nasal cartilage. Dx - amastigotes from skin lesion. Tx - Stibogluconate
What is the vector for Plasmodium, what are the two life cycles ? Explain the life cycle in humans
Vector - female Anapheles mosquito, life cycles - sexual cycle : sporogony, asexual cycle : schizogony.
Life cycle in humans : sporotzoites enter blood via anopheles bite --> sporozoites are taken up by hepatocytes-->multiplication into merozites-->merozoites are released and infect RBCs-->ring shaped trophozoites-->schizont filled with merozoites-->release from RBCs and infections of other RBCs
What is the sexual cycle of Plasmodium ?
What is the differnce between Plasmodium Falciparum to the other species ? Which species causes Quartan malaria with a 72h fever cycle ?
Sexual life cycle : in human RBCs some merozoites diff. into male and female gametocytes-->ingestion by anopheles-->fertilization in mosquito's gut-->zygote diff into ookinete-->oocyst filled with haploid sporozoites. Plasmodium falciparum can infect RBCs of all ages, all others only reticulocytes. Plasmodium Malaria has a 72h fever cyel
What are the clinical symptoms of Malaria ? Give 2 tests, which species can have latent infections, in which form ?
Clinical - Fever, chills, myalgias 2 weeks after bite. Later on fever becomes cyclic with upto 41C and vomiting. Splenomegaly, anemia.
Tests - 1. Thick/thin giemsa smears (NOTE !! banana shaped gametocytes of Falciparum within RBCs) 2.PCR.
Latent infections are Vivax and Ovale, in the form of hypnozoites
What is the tx for malaria ?
Acute - Chloroquine kills merozoites in blood. To kill hypnozoites - primaquine. Mefloquine for chloroquine resistant strains
Toxoplasma Gondii : what is the definitive host, what is intermediate hosts, What is the life-cycle in the human ?
Definitie host - cats and other felines. Intermediate hosts -humans and mammals. LIfe cycle in humans :
Ingestion of cysts in undercooked meat or from cat feces -->in the SI cysts rupture and release forms that invade gut wall-->taken up by Mac's-->diff. into tropohzoites(tachyzoites) within macs-->macs are killed and tropohozoites are released to infect more cells. If CMI is intact, parasites enter host cells in the brain,muscle and develop into cysts in which the parasites develop slowly (bradyzoites)
Toxoplasma Gondii : what is the life-cycle within the cat ? Also, what is the mode of human-to-human transmission ? When does it occur ?
Ingestion of cysts in raw meat (mice) -->bradyzoites are released from cysts in SI-->diff. into male/female gametes-->form oocysts that are excreted in feces.
Human-to-human : transplacentally --> occurs only if mother is infected for the first time during pregnancy
What are the clinical symptoms of Toxoplasma Gondii ? Give 2 tests , also tx
Symptoms : Most primary infections in immunocompetent patients are asymptomatic or may resemble Heterophil negative IM.
In congenital toxoplasmosis : abortion, encephalitis, chorioretinitis, jaundice, intracranial calcifications, blindness. Symptoms may develop only years after birth(menal retard).
Tests : 1.Immunoflourescence for IgM, 2.Giemsa stain for tropohzoites, or cysts in tissues. Tx- Sulfadiazine+Pyrimethamine
What are Enterobius vermicularis, Trichuris Trichuria ? what are this form general characterstics, what two types exist ?
They are nematodes (roundworms). They have cylindrical bodies and complete digestive tracts. They are covered with a cuticle and have different sexes. Divided into Intestinal and Tissue nematodes
What does enterobius vermicularis cause ? What are the hosts ? What is the life cycle ? Is it common ?
Enterobius vermicularis causes Pinworm infecftion. Humans are the only hosts. Life-cycle : Ingestion of worm eggs -->eggs hatch in SI -->larvae diff into adults and migrate to colon-->adult male &female mate in the colon-->female migrates from colon to anus at night and lays eggs outside and on the perianal skin-->eggs become infectoious in 6 hours and can reinfect via fingers (scratching). Most common Helminth in the US
What is the main clinical symptom of Enterobius Vermiculairs, give 2 test, give tx
Main symptoms : Perianal pruritis. Tests: 1.Eggs using the scotch tape technique (eggs are NOT in stool !!), 2.Adult worms in stools. Tx : Mebandazole --> kills only adult worms, not eggs.
What does Trichuris Trichuria cause ? What infects humans ? what is the life cycle ?
Causes Whipworm infection. Eggs in food or water infected with human feces infect humans. Life cycle : Eggs hatch in SI --> larvae diff into immature adults-->migrate to colon to mature --> mate, lay eggs--> eggs are passed in feces and are embryonated in warm soil.
Trichuris Trichuria : what are the clinical symptoms ? Dx ? Tx ?
Mostly asymptomatic, may cause diarrhea. May cause rectal prolapse in heavy infections in children. Dx - Barrel shaped eggs with a plug at each end in the stool. Tx - Mebendazole
Ascaris lumbricoides - what is it, how are humans infected, what is the life cycle ? What is special about this worm ?
Ascaris - intestinal nematode. Humans are infected by worm eggs in food or water infected with human feces. Life cycle - Eggs hatch in SI --> larvae migrate thru gut wall into blood--> to lungs --> climb up trachea and swallowed --> Become adults again in the SI --> live in lumen, do not attach --> lay eggs that pass in feces are are embryonated in soil. It is the largest intestinal nematod, upto 25cm
What are the clinical symptoms of Ascaris Lumbricoides ? What is the dx, tx ?
Major damage occurs during larval migration --> eosinophilic exudates in the lung. Malnutrition, obstruction.
Heavy worm burden --> eosinophilic ascaric pneumonia.
Dx - oval egg with irregular surface in stool. Tx - Mebendazole
Toxocara Canis - what group of nematodes does it belong to ? What is the definitive host, what are humans ? What is the life-cycle ?
Toxocara Canis - belongs to Nematodes whose larva cause disease. Definitive host - Dog, humans are accidental dead-end hosts.
Life cycle : Toxocara female lays eggs in dogs intestine --> eggs in soil--> humans ingest eggs --> hatch into larvae in SI --> larvae migrate to brain, liver, eyes --> larvae encapsulate and die
What are the clinical symptoms of Toxocara canis infection ? Also, two tests, and tx
Granluomas form around the encapsulated dead larvae and cause blindness, fever, hepatomegaly. Tests - 1.Serology, 2.Larvae in tissue. Tx -Mebendazole
What are Ancylostoma Duodenale&Necatur americanus cause ? What are they ? What is the infectious form ? What is the life-cycle ?
They are intestinal nematodes that cause Hookworm infections. The infectious form is filiariform larvae in soil.
Life-cycle : Filiariform larvae penetrate skin --> carried by blood to lungs --> migrate up trachea and swallowed --> Develop into adults in SI and attach to the wall via cutting plates or teeth --> lay eggs which are passed in feces -> eggs develop into rhabditiform larvae and then into filiariform larvae (infectious)
What are the clinical symptoms of Ancylostoma Duodenale and Necatur americanus ? Dx ? Tx ?
Symptoms - since the worms feed from capillaries in intestine villi anemia can occur. Also - ground itch at entry site. Eosiniophilic pneumonia during larval migration. Dx- Eggs in stool and eosiniophilia. Tx - Mebendazole
Strongyloides Stercoralis - what is it, what are the two life cycles ?
It is a nematode which larvae cause disease. Life cycles : :Life-cycle within humans : filiariform larvae penetrate skin --> migrate to lung, up trachea, swallowed -->enter SI, form adults --> lay eggs --> eggs hatch in mucosa forming rhabditiform larvae which are passed in feces --> some larvae can form filiariform larvae while in the SI and cause autoinfection. If patient is IC --> massive reinfection can occur with many filiariform larvae.
In the soil : the rhabditiform larvae passed in feces mature in warm soil to form mature male/female that mate and then the entire egg-larva-adult cycle can occur in the soil
What are the clinical symptoms of Strongyloids stercoralis ? dx ? tx ?
Symptoms - with low worm burden mostly asymptomatic , inflammation of SI mucosa can lead to diarrhea. In massive autoinfection -sepsis by enteric bacteria . Migration thru lung can cause pneumonia similar to Ascaris. Dx - larvae in stool. Tx - IVERMECTIN
Trichinella Spiralis - what is the reservoir, how are human infected ? what are humans ? what is the life-cycle ?
Reservoir is mammals, esp. pigs. Humans are infected by eating pigs' muscle with encysted larvae. Humans are dead-end hosts. Life-cycle : Larvae excyst and mature in the SI mucosa --> eggs hatch within adult females-->larvae are released via bloodstream to many organs however they develop only in striated muscle cells --> there they encyst within a fibrous capsule and eventually calcify
What are the clinical symptoms of Trichinella Spiralis ? Dx ? Tx ?
Symptoms - Diarrhea a few days after eating pork --> 2 weeks after --> fever, muscle pain, eosinophilia, subconjunctival hemorrhages, cardiac&CNS involvement. Dx - larvae within striated muscle. Tx - Thiabendazole is effective against the adult worms in early infection.
What are flat worms, what are their structure, how do humans acquire disease, what are the two classes ?
They have a round head - Scolex - and body composed of proglottids with the oldest proglottids producing eggs. humans usually acquire infection when eating undercooked fish containing larvae (except in cysticercosis and hydatid disease). The two classes are Cestodes(tape worms) and Trematodes(flukes)
What is the structure of Diphylobothrium Latum ? How are humans infected ?
In contrast to other cestodes, the scolex has sucking grooves (no suckers and no hooks). Proglottids are wider than they are longer. The eggs are oval with an operculum. Longest of the tapeworms -- up to 13m. Humans are infected by eating undercooked fish containing larvae.
What is the life cycle of Diphyllobothrium Latum ?
In the SI, the larve attach to mucosa and develop into adults --> they release eggs which are passed in feces --> embryos emerge from the eggs in water --> are eaten by crustacea (1st intermediate hosts) --> embryos develop into procercoid larvae --> curstacea are eaten by fish --> larvae develop into plerocercoid larvae in the fish muscle (2nd intermediate hosts) --> fish are eaten by humans (definite hosts)
What are the clinical symptoms of Diphyllobothrium latum ? Dx ? Tx ?
Clinical - Mostly asymptomatic, diarrhea, megaloblastic anemia due to B12 uptake by the worm may occur. Dx - finding charaecterstic eggs in stool. Tx - PRAZIQUANTEL
What is the second name of Hymenolepis Nana ? Is it common ? how big is it ? How is different from other tapeworms ?
Dwarf Tapeworm, it is the most common tapeworm, it's very small 3-5cm. Different from other tapeworms as its eggs are directly infectious (and not the larvae !), also, many (hundreds) of worms can be present at the same time..usually only one.
What is the life cycle of Hymenolepis Nana ? Clinical ? Dx ? Tx ?
Life-cycle - eggs hatch in the duodenum --> develop into cysticercoid larvae -> adult worms -->eggs are passed in stool or can autoinfect. Clinical -asymptomatic mostly. Dx- finding charecterstic eggs in stool with 8-10 polar filaments. Tx - Praziquantel
Which 2 diseases do Taenia Solium cause ? What is its structure ? What is the appearance of the eggs ?
Adult forms cause Taeniasis, larvae cause Cysticercosis. Structure - 4 suckers and circle of hooks on the scolex, gravid proglottids have 5-10 uterine branches. Eggs are similar to T.Saginata and Echinococcus eggs
What is the life-cycle of Taenia Solium ? What are humans in the cycle ? what are pigs ?
Life-cycle : humans eat undercooked pork meat containing cysticerci larvae -> larave attach to SI wall and mature to adults in 3 months (upto 5m) -->proglottids with eggs are passed in feces and are eaten by pigs --> a six-hooked embryo emerges in the pigs SI --> goes thru blood to skeletal muscle --> develop to cysticerci in the muscle . Humans are definitive hosts, pigs are intermediate hosts.
What is cysticercosis caused by Taenia solium ? What are the clinical symptoms of Taeniasis and cysticercosis ?
Cysticercosis occurs when a person ingests food/water infected with human feces containing Taenia solium EGGS --> eggs hatch in the SI --> oncosphere embryos migrate thru blood to many organs, esp. eyes and brain where they encyst to form cysticerci. Taeniasis is usually asymptomatic, diarrhea may occur. In cysticercosis, the cysticerci can act as space occuping lesions and are also inflammatory leading to headache, seizures, retinitis, or seeing the cysticerci floating in the eyes
What is the dx of Taneia solium diseases ? What is the tx ?
Dx - finding gravid proglottids w/5-10 uterine branches in stool, ELISA to detected its antigens. Tx- praziquantel
What disease does Taenia Saginata cause ? What is the structure ? How are humans infected ? What is the life-cycle ?
Diseases- Taeniasis. NO cysticercosis. Structure- scolex with 4 suckers but NO hooklets (unlike Solium). Gravid proglottids show 15-20 uterine branches. Eggs are similar to those of Solium. Humans are infected eating undercooked beef containing cysticerci. Life-cycle : in the SI - the larvae attach to the mucosa and take 3 months to become adults (upto 10m) --> proglottids detach with eggs, passed in feces-->eaten by cattle-->embryos hatch in cow's intestine-->via blood to skeletal muscle-->develop into cysticerci
Clinical symptoms of Taenia saginata, What is the dx of, what is the tx
Clinical - mostly asymptomatic, malaise...
Dx - gravid proglottids with 15-20 uterine branches in stool.
Tx- Praziquantel
What is Dipylidium Caninum, how are humans infected, clinical, dx, tx
Most common tapeworm (Cestode) of dogs, cats. Humans disease occurs when cat/dog fleas containing cysicerci are ingested. These develop into adult worms in humans SI. Mostly asymptomatic, some diarrhea. Dx- barrel-shaped proglottids in feces. Tx - niclosamide
Echinococcus Granulosus - what is it, which disease does it cause, what is its structure, which are definite hosts, which are intermediate hosts, what are humans ?
It is a cestode (Tapeworm), it causes Unilocular hydatid cyst. It is composed of a scolex w/only 3 proglottids (very small). Dogs are definite hosts, sheep are intermediate hosts. Humans are accidental dead-end hosts.
What is the life-cycle of Echinoccosu granulosus, what is the pathogenesis ?
Life-cycle : worms in the dog's intestine release eggs which are ingested by sheep (or humans..) --> oncosphere embryos emerge in the SI-->migrate to liver, lungs, bones, brain-->embryos develop into fluid filled Hydatid cysts and produce many protoscoleces in capsules --> cycle is complete when sheep internal organs are fed to dogs. Pathogenesis : The cyst acts as a space occuping lesion. Cyst fluid contains parasite antigens that can sensitize the host --> if cysts rupture --> anaphylactic shock and spread of protoscoleces
What are the clinical symptoms of Hydatid cysts caused by Echinococcus granulosus ? what is the dx, tx ?
Clinical - liver cysts can cause hepatic dysfunction, cysts in the lung can erode into a bronchus, in brain - headaches. Rupture - anaphylactic shock. Dx - microscopy showing brood capsules with protoscoleces, serology. Tx - Albendazole
What are Trematodes ? What are the 3 species of Schistosoma and what do you they affect ? What is special about Schistosomas and what is the structure of their eggs ?
Trematodes are flukes, subclass of Flatworms. 3 species - Schistosoma mansoni & Japonicum infect the GI tract, Hematobium infect the urinary tract. Special - schistosomas have two seperate sexes, unlike other trematodes which are hermaphrodites. Eggs - Mansoni : large lateral spine, japonicum - small lateral spine, hematobium - terminal spine
Schistosoma - where do the adults reside, what is the life cycle
Mansoni and Japonicum live in the mesenteric veins, Hematobium lives in veins draining the urinary bladder. Life-cycle : swimming cercariae pentrate skin-->diff. to larvae, enter blood-->carrier to arterial circulation-->reach their target veins-->female lays eggs which penetrate gut/bladder wall -->secreted in feces/urine-->hatch in fresh water-->ciliated larvae enter snails-->develop to form circariae which leave the snail and enter water again
What is the pathogenesis and the clinical symptoms of Schistosomas ? What is the dx, tx ?
Pathogenesis- mostly due to eggs which induce granulomas and fibrosis. Eggs also secrete proteolytic enzymes. Clinical Acute : itching-->2-3weeks later-->fever, lymphadenopathy. Chronic - GI hemorrhage, hepatosplenomegaly, Hematuria. Dx - finding eggs with charaecteristic appearance in stool,urine. Tx - Praziquantel
Paragonimus Westermani - what is it, what is its lifecycle
It is the lung fluke. Lifecycle - humans eat undercooked crab meat containing metacercariae larvae --> excyst in SI-->immature flukes penetrate SI wall and migrate to lung -->diff. into hermaphroditic adults in lung-->produce eggs that enter bronchioles that are coughed up or swallowed-->eggs reach sputum or feces-->in fresh water hatch into Miracidia-->enter snails, develop into larvae, then into circariae-->cercariae infect and encyst in crabs
What are the clinical symptoms of Paragonimus Westermani infection ? Dx ? tx ?
Clinical - worms in lungs exist in a fibrous capsule that predisposes to 2nd bacterial infection --> bloody sputum, cough, bacterial pneumonia. Dx- typical operculated eggs in sputum/feces. Tx - Praziquantel
What is fasciola hepatica, what is its life-cycle
It is the sheep liver fluke. Humans are infected by eating seaweed contaminated by larvae -->excyst in duodenum, penetrate gut wall-->reach liver, mature into adults-->adults produce eggs in bile ducts which are excreted in feces-->eggs hatch in fresh water and miracidia(larvae) enter snails-->develop into cercariae which leave snails and encyst on aquatic vegetation
What are the clinical symptoms of Fasciola ? Dx ? tx ?
Clinical - due to presence of worms in biliary tract - fever, hepatomegaly, obstructive jaundice. Dx - eggs in feces. Tx - Praziquantel
What does Wuchereria cause ? what is the vector, life-cycle ?
Wuchereria Bancrofti causes Filiarisis (with Elephantiasis). Vector is female Anopheles, or Culex mosquitoes. Lifecycle- infective larvae are deposited on skin with mosquito bite ->larvae penetrate skin, enter LN-->mature to adults after 1 year and produce microfiliariae-->circulate in the blood at night--> taken up by next mosqito bite-->within the mosquito produce infective larvae
What are the clinical symptoms, dx, tx or Wuchereia ?
Clinical - adult worms cause inflammation that leads to obstruction of lymph vessels-->elephantiasis with edema, fibrosis. Dx - thick blood smears at night. Tx - Diethylcarbamazine against the microfiliraiae --not against worms.
What is the species of Onchocerca that causes disease, what is the vector, what is the lifecycle ?
Onchocerca volvulus. Vector -female blackfly. Lifecycle- infective larvae are deposited with blackfly bite-->larvae migrate into subcutaneou tissue->differentiate to adults within dermal nodules->female produces microfilariae that are taken up by the next blackfly-->microfiliarie develop into infective larvae in the blackfly
What are the clinical symptoms, dx, tx of Onchocerca Volvulus ?
Clinical -pruritic nodules, microfiliarie in the eyes can lead to blindness, loss of subcutaneous elastic tissue leads to lizard skin. Dx -microfiliariae in skin biopsy. NOTE -- microfiliare do not circulate in blood !! blood smears not useful !. Tx - Ivermectin for microfiliariae, Suramin for worms
Loa Loa - what is the vector, what is the lifecycle ?
Vector- Deerfly, cryshopis. Cycle - deposits infective larvae on skin->wander in body->develop into adults->produce microfiliariae that circualte in blood during day->taken up by the next fly and diff into infecting larvae
Clinical symptoms of Loa Loa ? dx ? tx?
Clinical - subcutaneous edema and adult worms crawling across the eye. Dx - microfiliariae in blood smear. Tx - Dietyhylcarbazine against the microfiliariae
Dracunculus - what is the species, how are humans infected, what is the cycle
Dracunculus Medinensis. Humans are infected by swallowing water containing crustaceans infected with dracunculus larvae. Cycle : Larvae are released in SI-> migrate in the body->mature into adults, can reach 1m->females cause the skin to ulcerate and release motile larvae into fresh water->crustaceans eat the larvae that develop to infective forms
Clinical symptoms of Dracunculus Medinensis, dx ? tx ?
Clinical -papules that burn and itch. Dx - clinically, seeing the head of the worm in an ulcer. Tx - winding the worm on a stick + thiabendazole
Name 4 antifungal drug mechanisms and an example
1. Inhibition of fungal cell wall synthesis(Caspofungin), 2.inhibition of DNA synthesis(Flucytosine), 3.Alterations of fungal cell membrane(Amphotericin B, Azole drugs), 4.Prevention of mitotic-spindle formation (Grisofulvin
Explain how Caspofungin works(+2 fungi it inhibits), explain how Flucytosine works(+2 fungi it inhibits)
Caspofungin - Blocks fungal cell well synthesis by inhibiting synthesis of Beta-Glucan -->inhibitis Aspergillus and Candida.
Flucytosine : Nucleoside analogue of thymidine, inhibits DNA synthesis -->Cryptococcus, Candida
Explain how Amphotericin B works, how Azole drugs work. Explain how Grisofulvin work + examples
Amphotericin B - Disrupts fungi cell membrane by binding Ergosterol, component only of fungal membranes-->nephrotoxic.Used for example in disseminated fungal diseases.
Azoles - Inhibit Ergosterol synthesis. Used for systemic and opportunistic mainly. Grisofulvin - prevents mitotic spindle formation. Used in Dermatophytic infections.