Parasites

Enterobius vermicularis*

Embryonated eggs

Enterobius vermicularis

Adult Female

Tricuris trichiura

Adult female and adult male

Enterobius vermicularis*

(pinworm) Embryonated eggs (see larvae inside)

Symptoms- itchy perianal region

Diagnose- eggs in sticky tape test (no stool sample)

Treat- mebendazole, but child will probably recatch it.

Ascaris lumbricoides*

Adult female and adult male

Tricuris trichiura*

Fertilized, unembryonated egg

Symptoms- diarrhea, anemia, prolapsed rectum

Diagnose- eggs in stool Treatment- Mebendazole

Toxocara canis

Female and male adult

Ascaris lumbricoides*

Fertilized, unembryonated egg

Adult females lay 200,000 eggs/day

Infection by ingesting embryonated eggs —>hatch in SI—> migrate during fever or drugs Light infections are asymptomatic except when migrating, heavy infection —>malnutrition, peritonitis

Diagnose: Detect eggs in stool Treat: Mebendazole

Ancylostoma duodenale

Adult female and male

Toxocara canis Embryonated egg Diagnose- ELISA for antigens Treat- Mebendazole, steroids for inflammatory resp.

Hookworm* Fertilized, embryonated egg Symptoms- iron deficiency anemia Diagnose- Eggs in Stool Treat- mebendazole with albendazole

Ancylostoma duodenale

Infectious larva

Strongyloides stercoralis Parasitic female

Strongyloides stercoralis Free-living adult (in soil only)

Taenia saginata Adult

Strongyloides stercoralis* Second-stage larva The only larvae you will see in stool Causes malabsorption (like giardia)

Taenia saginata/solium* Tapeworm Embryonated, infectious egg All tapeworm eggs look the same, you can’t tell them apart—not specifically diagnostic Look for proglottids

Taenia saginata/solium* Gravid proglottid Beef Tapeworm More than 12 uterine branches per side Asymptomatic, but you may find proglottids on bedsheets Diagnose- Proglottid in feces Treat- Praziquantel

Echinococcus granulosus Adult

Taenia solium* Gravid proglottid Pork Tapeworm Less than 10 uterine branches per side Asymptomatic, but you may find proglottids on bedsheets. Larva migrationÆ cysticercosis, vision impairment, CNS (seizures) Diagnose- Proglottid in feces Treat- Praziquantel if asymptomatic; Surgery, steroids and albendazole (crosses BBB) or praziquantel if cystcercosis

Schistosoma mansoni* Embryonated egg, lateral spine Found in tropical Africa, S. America, Mid East (Egyptian mummies), Caribbean Acute- High Fever Chronic- Portal Hypertension, GI bleeding, esophageal varices, ascites, cor pulmonale Diagnose- Eggs in Stool, ELISA Treat- Praziquantel

Echinococcus granulosus* Hydatid cyst/sand? Sheep/dog disease Brood capsule with protosolices Eggs look just like other tapeworms (Taenias) Pathology- make cysts if ingested in eggs, may grow cysts in bone, liver, brain, etc… Diagnose- Hooklets, hydatid sand in sputum? Treat- surgery, albendazole, mebendazole?

Schistosoma mekongi* Embryonated egg, no spine

Schistosoma japonicum Embryonated egg, no spine Found in Asia, especially China Diagnose- Eggs in stool, ELISA

Schistosoma mansoni Miracidium caught in the act of hatching

Schistosoma haematobium* Embryonated egg, terminal spine Only thing in urine Found in Africa, Mid East, Caribbean Acute- High Fever Chronic- Portal Hypertension, GI bleeding, esophageal varices, ascites, cor pulmonale Diagnose- Eggs in stool, ELISA Treat- Praziquantel

Malaria Sporozoites in mosquito stomach

Schistosoma mansoni Miracidium

Plasmodium falciparum* Gametocyte Diagnostic for P. falciparum Only malaria is in blood Symptoms- fever, shaking chills, hemolysisÆ jaundice, icterus, enlarged spleen, cerbral malaria Diagnose- gameteocytes in blood Treat- qunine, quinolone, tetracycline, clindamycin, sulfadoxine. Primaquine for liver stage.

Malaria Exo-erythrocytic stages in liver parenchymal cell

Plasmodium falciparum* Signet ring stage

Plasmodium falciparum* Gametocyte Diagnostic for P. falciparum Only malaria is in blood Symptoms- fever, shaking chills, hemolysisÆ jaundice, icterus, enlarged spleen Diagnose- Gametocytes in blood Treat- qunine, quinolone, tetracycline, clindamycin, sulfadoxine

Plasmodium vivax * Trophozoite Note infected RBC is larger in diameter than noninfected RBCs. Symptoms- fever, shaking chills, hemolysisÆ jaundice, icterus, enlarged spleen. Can have relapse (hypnozoite stage in liver) Treat- primaquine—watch for deficient glucose-6- phospate dehydrogenase

Malaria Cerebral malaria, experimental infection in monkey

Plasmodium ovale Note: crenulated appearance of infected RBC

Plasmodium malariae* Note infected RBC is about the same diameter as noninfected cells Symptoms- fever, shaking chills, hemolysisÆ jaundice, icterus, enlarged spleen. Can have relapse (hypnozoite stage in liver) Treat- prmiaquine—watch for deficient glucose-6- phospate dehydrogenase

Malaria Exflagellation of the microgametocyte of a malaria parasite. Each “flagella” is actually a male gamete

Malaria Oocyte in infected mosquito stomach

Toxoplasma gondii Sporulated and unsporulated oocytes

Toxoplasma gondii

Dark blue footballs are tachyzoites

Pneumocystis jiroveci Cyst

Pneumocystis jiroveci Silver stain of lung biopsy from an AIDS patient

Giardia lamblia* Cyst (diagnostic) Beaver feaver Symptoms- intermittent diarrhea and constipation, weight loss, malaise, steatorrhea (flatten villi) Diagnose- cysts in stool are sufficient, may find trophozoites too Treat- metronidazole (antabuse)

Giardia lamblia* Trophozoite Beaver fever Symptoms- intermittent diarrhea and constipation, weight loss, malaise, steatorrhea (flatten villi) Diagnose- cysts in stool are sufficient, may find trophozoites too Treat- metronidazole (antabuse)

Entameba histolytica Trophozoite (diagnostic) See eaten RBCs in cytoplasm Symptoms- asymptomatic, diarrhea, or amoebic dysentery. (Dysentery could also be shigella or salmonella), flask shaped ulcers Diagnose- trophozoites in stool Treat- Metronidazole (antabuse) and iodoqunol for intestinal amebiasis, metronidazole in higher doses for extraintestinal. Prevent- FILTER water

Giardia lamblia Trophozoites Beaver fever Symptoms- intermittent diarrhea and constipation, weight loss, malaise, steatorrhea (flatten villi) Diagnose- cysts in stool are sufficient, may find trophozoites too Treat- metronidazole (antabuse)

Entameba histolytica Trophozoite (diagnostic) See eaten RBCs in cytoplasm Symptoms- asymptomatic, diarrhea, or amoebic dysentery. (Dysentery could also be shigella or salmonella) , flask shaped ulcers Diagnose- trophozoites in stool Treat- Metronidazole (antabuse) and iodoqunol for intestinal amebiasis, metronidazole in higher doses for extraintestinal. Prevent- FILTER wate

Entameba histolytica Cyst, looks like E. dispar. Not diagnostic-- infectious See chromatin bar and 4 nuclei Symptoms- asymptomatic, diarrhea, or amoebic dysentery. (Dysentery could also be shigella or salmonella) , flask shaped ulcers Diagnose- trophozoites in stool Treat- Metronidazole (antabuse) and iodoqunol for intestinal amebiasis, metronidazole in higher doses for extraintestinal. Prevent- FILTER water

Entameba histolytica Cyst, looks like E. dispar. Not diagnostic See chromatin bar and nuclei Symptoms- asymptomatic, diarrhea, or amoebic dysentery. (Dysentery could also be shigella or salmonella) , flask shaped ulcers Diagnose- trophozoites in stool Treat- Metronidazole (antabuse) and iodoqunol for intestinal amebiasis, metronidazole in higher doses for extraintestinal. Prevent- FILTER water

Entameba histolytica Trophozoite (diagnostic) See eaten RBCs in cytoplasm Symptoms- asymptomatic, diarrhea, or amoebic dysentery. (Dysentery could also be shigella or salmonella) , flask shaped ulcers Diagnose- trophozoites in stool Treat- Metronidazole (antabuse) and iodoqunol for intestinal amebiasis, metronidazole in higher doses for extraintestinal. Prevent- FILTER water

Cryptosporidium parvum Oocysts—look like little little red dots From suckling Symptoms- diarrhea, lethal in AIDS patients, self limited in immunocompetent hosts Diagnose- acid fast stain for oocysts in stool Treatment- none, only prevention (usually self limited) Prevent- FILTER water