Download PARASITOLOGY SUMMARY (Apicomplexa, Plasmodium spp.) and more Cheat Sheet Parasitology in PDF only on Docsity!
APICOMPLEXA
General Life Cycle Sporozoites → Merozoites → Micro/macrogametocyte → Zygote → Oocyst → Sporulated oocyst → Sporozoites Cryptosporidium parvum Cryptosporidium hominis Infective Stage Thick walled oocyst Diagnostic Stage Thick walled oocyst via stool exam DO NOT fluoresce under UV light Major host Cattle Treatment Nitazoxanide; resistant to chlorine Clinical Features Cryptosporidiosis Immunocompetent: self-limiting diarrhea Immunocompromised: severe progressive diarrhea, acute gangrenous cholecystitis MOT Feco-oral route (water/food) Direct contact with infected animals Unique Features “donut shaped” oocyst in kinyoun modified acid fast stain Cyclospora cayatenensis Infective Stage Sporulated oocyst (contains 2 sporocyst with 2 sporozoites each) Diagnostic Stage Oocyst via stool exam Fluoresce under UV light Major host Humans; No animal reservoir Treatment Co-trimoxazole Clinical Features Cyclosporiasis Immunocompetent: Diarrhea alternates with constipation Immunocompromised: bile duct involvement, prolonged symptoms MOT Feco-oral (raspberries, basils, cilantro) Site: Jejunum Unique Features Red-violet in modified acid-fast stains
Cystoisospora belli Infective Stage Mature oocyst Diagnostic Stage Oocyst via stool microscopy Fluoresce under UV light Major host Humans; no animal reservoir Treatment Co-trimoxazole Clinical Features Cystoisosporiasis Common among AIDS patients Immunocompetent: asymptomatic Immunocompromised: severe diarrhea and fat malabsorption MOT Feco-oral route Unique Features Oocyst - walls are thin and transparent Toxoplasma gondii Infective Stage Man: Bradyzoite (tissue cyst) IH: Oocyst (feline feces) Tachyzoite (transplacental) Diagnostic Stage Tachyzoites (tissue biopsy) Cyst Major host Cat Treatment Pyrimethamine and Sulfadiazine Clinical Features Toxoplasmosis Acute - painful swollen lymph nodes (mesenteric LN and liver) Chronic - encephalitis, chorioretinitis Congenital - severe during 1st trim, highest transmission in 3rd trim Triad: hydrocephalus, intracerebral calcification, chorioretinitis MOT Eating undercooked meat Unique Features Reddish purple nucleus Blue cytoplasm (giemsa stain) Oocyst: ovoid and thin-walled Cyst: Brain tissue - spherical cyst Myocytes - elongates cyst During chronic stage only Trophozoite: crescent shaped, pointed anteriorly, blunt posteriorly Tachyzoite - acute; pseudo Bradyzoite - chronic; true Congenital Toxoplasmosis Spherical cyst: Elongated cyst: Tachyzoites: Bradyzoites: Oocyst:
PLASMODIUM
Plasmodium spp Infective Stage Man: Sporozoite Mosquito: Gametocyte Diagnostic Stage Trophozoite (ring form, mature) Schizont – thin and thick blood smear Major host Humans Treatment Periodicity P. vivax - Benign tertian (48h) P. falciparum - Malignant tertian (48h) P. ovale - Benign tertian (48h) P. malariae - Quartan (72h) P. knolesi - Quotidian (24h) Clinical Features Relapse: P. vivax and P. ovale MOT Bite of female anopheles mosquito Morphology Ring form / Early trophozoite Mature trophozoite Schizont Gametocyte Affinity P. vivax - young RBC/reticulocytes P. falciparum - all stages P. malariae - old RBC/senescent P. knolesi - all stages Plasmodium falciparum Ring-form/ Early Trophozoite Headphone type with double chromatin dot Found in the periphery of RBC (accolé appliqué) Mature trophozoites Hemozoin - metabolite of hemoglobin Maurer’s clefts - Irregular, reddish stippling, rod or wedge-shaped structures Schizont Rarely seen in P. falciparum, except in severe cases Merozoites: 8-24 (small), dark pigment clumped in one mass Gametocyte Microgametocyte (R) - male, pale nucleus Macrogametocyte (L) - female - darker Laveran’s bib - remnants of RBC Banana shaped, spindle shaped
Plasmodium vivax Ring-form/ Early Trophozoite Signet-ring appearance with the following characteristics:
- Thick cytoplasm
- Single, large chromatin dot Mature trophozoites Ameboid cytoplasm
- Pseudopodial processes
- Large vacuoles Schüffner’s dots
- Small, yellowish-brown pigment granules in cytoplasm Schizont Number of Merozoites: 12- Stipplings: Schüffner’s dots Gametocyte Microgametocyte - male; diffuse chromatin Macrogametocyte - female; compact, eccentric chromatin Cytoplasm - darker Blue Plasmodium malariae Ring-form/ Early Trophozoite Sturdy cytoplasm and a large chromatin dot “Bird’s-eye” forms may appear Mature trophozoites compact cytoplasm, large chromatin dot band-forms and/or “basket” forms with coarse, dark-brown pigment can be seen Ziemann’s stipplings may be present Schizont Merozoites: 6- Arranged as a rosette pattern Gametocyte May almost fill the infected red blood cell Cytoplasm - blue Chromatin - pink to red
