parasitology - blood tissue protozoans/coccidians

trypanosoma brucei brucei

causes african sleeping sickness/african trypanosomiasis

trypanosoma brucei brucei

located in west and east africa, wild game (cattle) is reservoir

trypanosoma brucei brucei

definitive host: humans, wild game

intermediate host: glossina (tsetse fly)

trypanosoma brucei brucei

trypomastigote stage found in blood, lymph, or CSF; epimastigote stage in fly

trypanosoma brucei brucei

method of infection: trypomastigote in salivary gland of fly injected in blood meal

diagnostic stage: trypomastigote in peripheral blood or lymph early, CSF late

trypanosoma brucei brucei

trypomastigote: 3-5 folds in undulating membrane, kinetoplast (mitochindrial DNA) is small, nucleus in middle, posterior end is round

trypanosoma brucei brucei

symptoms: chancre at site of fly bite, swollen lymph nodes, fever, headache, night sweats with fever peaks every 10 days, antigenic itching of outer glycoprotein coat (CSG) and high IgM levels, autoagglutination of RBC (antigenic) causes anemia, neurological changes, altered reflexes, motor changes, coma, death

t.b. rhodensiense

CNS inflammation and cardiac changes, 1-6 months

t.b. gambiense

CNS inflammation, 6-12 months

t.b. rhodensiense

mortality in untreated cases is 95-100%

t.b. gambiense

mortality in untreated cases is 50%

trypanosoma brucei brucei

treatment: early (suramin, elfornithine, pentamidine, isethionate), late (melarsoprol)

trypanosoma cruzi

causes chaga’s disease/American trypanosomiasis

trypanosoma cruzi

located in mexico, central and south america

trypanosoma cruzi

host: human, other animals

intermediate: reduviid bug (triatoma), kissing bugs, flying bed bugs, barbers

trypanosoma cruzi

infective stage: trypomastigote in feces of bug

diagnostic stage: amastigotes in tissue, trypomastigotes in blood smear

trypanosoma cruzi

trypomastigote: S or C shaped, pointed posterior end, large terminal kinetoplast

trypanosoma cruzi

amastigote: bite site, found in heart muscle, liver, CNS macrophages; Leishman donovan (LD) bodies are round or oval, nonflagellated, have a nucleus, kinetoplast, kinetosome

NNN

the epimastigote of trypanosoma cruzi grows on _____ medium

xenodiagnosis

allow uninfected bugs to feed on patient and examine the bugs for parasites, with trypanosoma cruzi

serology tests

machado complement fixation test, intradermal test, indirect hemagglutination, indirect fluorescent antibody stain

trypanosoma cruzi

symptoms: chagoma/chancre at site of bite, acute phase (fever, weakness, enlarged lymph nodes, liver and spleen), romana’s sign (unilateral swelling of face if bitten there), chronic phase (destruction of ganglia of autonomic nervous system/megaesophagus and megacolon), heart problems due to cross reacting with tissues

leishmania species

causes cutaneous and visceral leishmaniasis (kala azar)

cutaneous leishmania

L. mexicana, L. braziliensis, L. tropica

visceral leishmania

L. donovani, L. tropicana

leishmania tropica

located in mediterranean, southwest asia, middle east, north and central america

leishmania mexicana

located in central and south america, mexico, texas

leishmania braziliensis

located in rural distribution in central and south america

leishmania donvani

located in north africa, east africa, asia, mediterranean, south america

leishmania tropica

host: humans, dogs, gerbils

leishmania mexicana and braziliensis

host: humans, guinea pigs, monkeys

leishmania donvani

host: humans, dogs, various rodents

leishmania species

intermediate host: sand fly (phlebotumus, lutzmyia)

leishmania species

infective stage: promastigote found in the gut of a sandfly

diagnostic stage: amastigote in cells of mononuclear phagocyte system (RE system)

leishmania mexicana and braziliensis

leishmania found in skin and mucous membranes

leishmania donvani

leishmania found in bone marrow, liver, or spleen

leishmania donvani

leishmania found in either skin and mucous membrane or bone marrow, liver, or spleen

leishmania species

diagnosis: finding amastigotes in biopsy of skin, bone marrow, spleen, etc

rK39 rapid test

what is the serologic testing for leishmania species that detects antibodies?

leishmania

skin and mucous symptoms: moist papule (3-6 months), dry papule (6-18 months), papules may heal themselves or progress to cause ulceration of mucosal surfaces, leading to erosion or polyp formation

leishmania species

visceral symptoms: papule at site of bite (6-12 months), spiking fever, chills, sweating, diarrhea, dysentery, weight loss, anemia, leukopenia, elevated globulin levels, and spleen, liver, and lymph node enlargement

leishmania species

treatment: sodium stibogluconate, meglumine antimonate, lipid encapsulated amphotericin B, pentamidine isethionate, miltefosine orally, paromomycin

sporozoans

obligate intracellular protozoans with gliding motility, babesia species and coccidians

sporogony, gametogony

what is the sexual phase of sporozoans?

schizogony, merogony

what is the asexual phase of sporozoans?

babesia species

multiplies in RBCs, must distinguish from malarial parasites

babesia species

located worldwide, martha’s vineyard, nantucket

babesia species

host: ixodes tick (deer tick)

intermediate host: human

babesia species

diagnostic stage: trophozoites in blood smears lie singly, in pairs, tetrads

babesia species

symptoms: 2-3 weeks after bite of infected tick, fever and chills, hemolytic anemia, mild spleen and liver disease, resembles malaria

toxoplasma gondii

host: cat

intermediate: any vertebrate, most birds, animals, including humans

toxoplasma gondii

cat gets infection by ingestion of oocysts from another cat or tissue of infected mice, undergoes sporogony and schizogony in cat intestine

toxoplasma gondii

diagnostic stage: tachyzoites, pseudocysts (bradyzoites) in tissues

infective stage: oocysts from cat feces or bradyzoites in cyst of infected tissue

toxoplasma gondii

symptoms: usually asymptomatic, lymph node swelling and fever, transmitted across placenta (visceral and cerebral involvement, stillbirth, mental retardation, cerebral calcifications)

IgG and IgM antibody testing, ELISA, indirect FA, PCR

what is the serological testing for toxoplasma gondii?

sarcocystis species

host: humans, dogs, cats

sarcocystis species

diagnostic stage: oocysts in feces

infective stage: ingestion of sarcocyst in undercooked meat or oocysts in feces

sarcocystis hominis

intermediate: cattle

sarcocystis suihominis

intermediate: pig

sarcocystis hominis and suihominis

2 sporocysts each with 4 sporozites

c. belli

2 sporocysts with 4 sausage shaped sporozoites in each

sarcocystis species

oocysts from infected humans ingested by intermediate host, sporozoites are released from oocysts and invade muscle tissue and form sarcocysts in intermediate host, humans become infected when they eat undercooked meat with sarcocysts or ingest oocysts (c. belli)

sarcocystis species

symptoms: in immunocompromised people, severe diarrhea, fever, weight loss

c. belli

symptoms: in immunocompromised people, anorexia, nausea, abdominal pain, diarrhea, malabsorption

cryptosporidium species

asexual and sexual cycle occurs in the same host, invades GI epithelium

cryptosporidium species

host: vertebrates, including humans

cryptosporidium species

infective stage: oocysts from fecally contaminated food or water

cryptosporidium species

symptoms: asymptomatic, immunocompetent people have diarrhea for 1-2 weeks, immunocompromised people have diarrhea with substantial loss of fluids and can be life threatening

cryptosporidium species

diagnostic stage: oocysts in feces that are round/oval, contain 4-6 sporozoites, acid fast

cyclospora cayetanensis

fecal oral route of transmission

cyclospora cayetanensis

infectious stage: oocyst

cyclospora cayetanensis

irregularly acid fast and appears wrinkled in appearance, autofluoresces with UV light, self limiting diarrhea with nausea, vomiting, cramping, low grade fever