Blood Parasites Flashcards
L. donovani Infection
Visceral leishmaniasis, Promastigotes infective, Reticuloendothelial cells infected Symptoms: Anemia, Leukopenia, Hepatomegaly and spleenomegaly, Fatal in 1-2 years (if untreated) Diagnosis: Giemsa-stained blood, bone marrow, tissue biopsy, Amastigote stage diagnostic, Serology, PCR
L. tropica Infection
Cutaneous leishmaniasis, Promastigotes infective, Skin lymphoid tissue infected Symptoms: 2 cm red papule at bite site, Lesions ulcerate, intense itching, Lesions usually self-heal Diagnosis: Giemsa-stained fluid underneath ulcer bed, Amastigotes within monocytes diagnostic, Serology (CDC offers IFA)
L. braziliensis Infection
Mucocutaneous leishmaniasis, Promastigotes infective Reticuloendothelial system infected Symptoms: Ulcers of oral and nasal skin and mucosa, Disfiguring lesions of nose, lips and palate, Edema of surrounding tissue, Death due to secondary bacterial infection Diagnosis: Giemsa-stained biopsy of ulcer, Amastigote form diagnostic, Culture of infected material for promastigotes, Serology (CDC offers IFA)
T. gambiense Infection
Vector: Glossina tsetse fly Disease: West African sleeping sickness, Lymphatic system and CNS infected Trypomastigotes (mature flagellate) infective Symptoms: Ulceration at bite site, Lymphadenopathy: Winterbottom’s sign, Tremors, dementia, encephalitis, Coma and death Diagnosis: Giemsa-stained blood, lymph node aspirate, CSF, Trypomastigote satge diagnostic, Elevated IgM and proteins in serum and CSF
T. rhodesiense Infection
Vector: Glossina tsetse fly, Cattle, sheep and wild animal reservoirs Disease: East African sleeping sickness, Lymphatic system and CNS infected Rapid and fulminating disease Trypomastigotes infective Symptoms: Rapid weight loss, anorexia, Fever and chills, Lymphadenopathy absent, Confusion, dementia, personality changes, Death within 9-12 months Diagnosis: Giemsa-stained blood, lymph node aspirate, CSF, Trypomastigote satge diagnostic, Elevated IgM and proteins in serum and CSF
T. cruzi Infection “Chagas’ disease”
Vector: Reduviid bug (kissing or triatomid bug), Trypomastigotes passed in bug’s feces May be asymptomatic, acute or chronic; Multiple tissues infected (heart, brain, liver, eye) Cats, dogs, armadillos and opossums Symptoms: Fever, chills, malaise, myalgia, Development of Chagoma, Unilateral edema of eyelids (Romanas’ sign), one eye will be swollen shut, Megacolon, megacardia, Most severe in children under 5 years age Diagnosis: Giemsa-stained blood slides specimen of choice, Trypomastigote satge diagnostic, Serology (CF, IFA)
Filariasis Diagnosis
Differentiated by type of periodicity: Diurnal or Nocturnal, Location of microfilariae in host, Microfilariae morphology, Presence or absence of sheath around worm, Distribution of nuclei within tip of worm
W. bancrofti
Disease: Elephantiasis Vector: Culex and Anopheles mosquitoes Asymptomatic or Symptomatic: Fever and chills, Lymadenopathy, Eosinophilia, Elephantiasis of leg, breast, scrotum Laboratory diagnosis: Nocturnal periodicity, Giemsa-stained blood smears for microfilariae, Pointed tail without nuclei, Presence of sheath around the ends, Recovery of microfilariae through Nucleopore filter, Serology
B. malayi
Presence of 2 nuclei in tail tip set apart from the rest
Loa loa
Disease: Loiasis (African eye worm infection) Vector: Chrysops deerfly Invasion: Blood and subcutaneous tissues Clinical picture: Pruritis and pain, Calabar swelling, Migrating worms visible across the eye and nose Laboratory diagnosis: Diurnal periodicity, Giemsa-stained blood smears for microfilariae, Tail with continuous row of nuclei, Presence of sheath around the ends, Extraction of worm from eye, Serology, More common in women than men
O. volvulus
Disease: River blindness Vector: Simulium blackfly Invasion: Subcutaneous tissue, skin, eye Clinical picture: Chronicity, Infected subcutaneous nodules, Allergic reactions, Eye lesions leading to blindness Laboratory diagnosis: Giemsa-stained tissue (skin snips) smears, Continuous row of nuclei in tail but not in the tip, Absence of sheath around the ends, Recovery of worm from infected nodules, Opthalmologic examination for residing worms, Serology, No periodicity observed
Toxoplasma gondii
Disease of blood and lymphatic vessels Definitive host: Domestic cats Intermediate hosts: mice, cows, pigs, humans Life cycle: Sexual and Asexual Transmission routes: Coming in contact with cat feces (hand-to-mouth), Ingestion of contaminated meat from cattle, pigs, Transplacental (in utero) Clinical presentation: Asymptomatic infection, Generalized symptoms, Congenital infection, Cerebral infection, Infection in immunocompromised, Laboratory diagnosis, Serology (ELISA, IFA), Less common, microscopy of tissue and animal inoculation
Borrelia burgdorferi
Vector: Tick Ixodes dammini Animal reservoirs: mice and deer Clinical symptoms First phase: Bull’s eye rash at bite site, flulike illness Second phase: Heart problem, facial paralysis, meningitis Third phase: Months or years later, arthritis, joint damage Laboratory diagnosis: Serological tests (ELISA, IFA, Western blot); antibodies (even IgM) persist for years, Clinical symptoms and exposure history, Culture, Tissue microscopy (Silver stain, DFA), PCR (less reliable)
