parasites Flashcards
Babesiosis
Babesia microti
Globally Common
Deer tick
Small rodents. Human (incidental)
By deer tick (also transmits Lyme disease)
RBCs only
Hemolytic anemia and thrombocytopenia. Rare: hepatosplenomegaly.
Blood smear (Maltese cross). Molecular analysis (CDC can do this). (some scientists think this looks like malaria)
Atovaquone and azithromycin. Clindamycin and quinine.
Both humoral and cellular factors are involved in immunity to babesiosis.
Stay out of the woods, especially in springtime (tick nymphs); wear DEET in woods
Cryptosporidiosis
Cryptosporidium hominis / parvum
Globally common
Human
livestock
Fecal-oral. Water supply (resistant to mild chlorination)
Intestine
Lose 12 L of water per day (20 L in AIDS). Otherwise similar to Giardia.
Cysts in stool (acid fast stain)
-few labs do immunofluorescence (IHC)
There are no effective drugs against cryptosporidium. Oral rehydration.
immunocompromised: nitazoxanide long course
immunocompetent: short course of above…
Possible immunity (self-limiting suggest role of immunity)
Boil water, or filter
Malaria
Plasmodium falciparum / knowlesi / vivax / ovale / malariae
Globally common
Mosquito
Humans, primates (for P. knowlesi)
Bite from female Anopheles. Needle sharing
RBCs, liver
Fevers and chills, synchronous with merozoites (24hrs for P. falciparum and P. knowlesi, 48hrs for P. vivax and P. ovale, 72hrs for P. malariae). Cerebral malaria (not in kids t have immune responses that assist Plasmodium). Anemia, especially in the young. Respiratory distress syndrome.
Blood smear. P. falciparum makes multiple rings per RBC. Can be difficult to distinguish different species by blood smear.
Chloroquine, mefloquine, quinine, malarone (atovaquone and proguanil)
Cannot make an effect immune response due to antigenic variation mechanisms
Prophylactic malarone. Repel and net mosquitos. New vaccine has some effectiveness. Reduce mosquito populations. Duffy negative (endemic to Africa) prevents P. vivax infection. GATES: RTS,S vaccines
Echinococcosis (Hydatid disease)
Echinococcus granulosus
Other
Canine tapeworm
Dogs
Ungulates, humans
Ingest eggs from dogs that ate livestock meat (fecal-oral transmission)
Lungs, liver, spleen, kidney, heart, bones, CNS
Hydatid cysts (liver and lung), anaphylaxis upon rupture
Imaging, serology
Surgical removal, percutaneous drainage, albendazole
Antibodies to hydatid cyst
De-worm dogs. Don’t feed them livestock
Cysticercosis (Taenia saginata)
Taenia saginata
Neglected in USA
Beef tapeworm
Humans
Cows
Ingest cysticeri from meat (taeniasis), ingest eggs from feces (cysticercosis)
Intestine
Taeniasis: Nausea, vomiting, diarrhea, weight loss, abdominal discomfort. Cysticercosis: Neurocysticercosis
Proglottids in stool, imaging
Praziquantel, niclosamide or albendazole, dexamethasone (to reduce inflammation)
Reinfection possible
Cook your beef
Cysticercosis (Taenia solium)
Taenia solium
Neglected in USA
Pork tapeworm
Humans
Pigs
Ingest cysticeri from meat (taeniasis), ingest eggs from feces (cysticercosis)
Intestine, lung, any tissue…BRAIN
Taeniasis: Nausea, vomiting, diarrhea, weight loss, abdominal discomfort. Cysticercosis: Neurocysticercosis
Proglottids in stool, imaging
Praziquantel, niclosamide or albendazole, dexamethasone (to reduce inflammation)
Reinfection possible
Cook your pork
Cysticercosis (Diphyllobothrium latum)
Diphyllobothrium latum
Neglected in USA
fish tapeworm
Humans
Copepods in fish
Raw or undercooked fish
Intestine
B12 deficiency, anemia
Proglottids in stool, imaging, pernicious anemia
Praziquantel, niclosamide or albendazole, dexamethasone (to reduce inflammation)
Reinfection possible
Cook or freeze your fish
Trypanosomiasis
Trypanosoma brucei / rhodesiense / gambiense
sub-Saharan only
Sleeping sickness
Humans
Tsetse fly
Bite from tsetse fly
Blood (never intracellular)
Lymphadenopathy, dementia, confusion, motor impairment, sleepiness, death through coma.
Blood smear, CSF analysis (T. rhodesiense), card agglutination test (not in USA, inaccurate)
Early stage: pentamidine, suramin. Late (post-BBB) stage: malarsopral, eflornithine (+/- nifurtimox)
None. Antigenic variation by pathogen
Vector control, vector avoidance, aggressive treatment
Chagas Disease
Trypanosoma cruzi
Neglected in USA
Reduvid bugs
Rats, cats, dogs, oposums, humans (dead end)
Bite from reduvid bug (with fecal contact). IV drug use, transplantation, transfusion.
Blood, lymph, tissues
Acute: 2-4 months after bite, fever, chagoma (Romana’s sign: swollen lateral eye), organ failure especially in children.
Chronic: 10-20 years after bite, no circulating trypomastigotes, only persistent amastigotes in tissue, causes chronic inflammation, manifests as a heart attack.
Acute: trypomastigotes in blood, antibody test. Chronic: xenodiagnosis
Acute: benznidazole, nifurtimox. Chronic: none
Antibodies are detectable
Vector control, good housing, screen blood supplies
Leishmaniasis
Leishmania mexicana / braziliensis / chagasi
Globally common
Sandfly
Humans
Bite from sandfly
Blood and tissues
- Cutaneous leishmaniasis: ulcerative sore at primary site, with satellite lesions. Spontaneous healing.
- Mucocutaneous leishmaniasis can spread years later and ulcurate the nasopharynx.
- Visceral leishmaniasis causes fever, wasting, splenohepatomegaly.
Staining for amastigotes
- Cutaneous: self-resolving.
- Mucocutaneous: amphotericin B (expensive) or antimonials.
- Viceral: Amphoteracin B, miltefosine.
Strain-specific
Vector control, vector avoidance, aggressive treatment
Trichinosis
Trichinela spiralis
Other
Tissue worm
Bears and swine
Humans (dead end)
Ingest undercooked meat from bear or pig
Muscle and intestine
Nausea, cramps, fever, conjunctivitis, muscle pain, cardiac and neural dysfunction
Eosinophilia, periorbital edema, myositis, fever, serology
Mebendazole, albendazole, corticosteroids
Antibodies are detectable
Cook or freeze your pork and bear meat
Toxocariasis
Toxocara canis / cati
Neglected in USA
Tissue worm
Dogs / cats
Humans (incidental)
Ingest eggs from soil
Blood
Local necrosis, hepatomegaly, pulmonary complications, ocular lesions, neurological symptoms
ELISA, history of geophagia
Mebendazole, albendazole, corticosteroids
Asthmatic and immune hypersensitivity common
De-worm dogs. Dispose of dog waste
Pinworm
Enterobius vermicularis
Other
Lumenal worm
Human
none
Ingest eggs from another person (fecal-oral transmission)
Intestine
Perianal pruritus, urogenital invasion, psychological trauma
Scotch tape test
Pyrantel pamoate, mebendazole, albendazole
None
Don’t consume human feces
Whipworm
Trichuris trichuria
Other
Lumenal worm
Human
none
Ingest eggs from soil (fecal-oral transmission)
Intestine
Bloody stool, bacteremia, anemia, prolapse, impaired growth
Eggs in stool
Ivermectin, mebendazole or albendazole
Some evidence for acquired immunity
Wash and cook your produce
Ascariasis
Ascaris lumbricoides
Globally common (NDP)
Lumenal worm
Humans
none
Ingest eggs from soil (fecal-oral transmission)
Intestine
Intestinal obstruction, poor development
Eggs in stool
Ivermectin, mebendazole or albendazole
Allergic inflammation from larval migration through lungs
Wash and cook your produce
