SPOROZOANS (contd.) *General Characteristics* Tissue parasites Obligate parasites Have no definite organelle for locomotion Have complex life cycle with alternating sexual and asexual generations Asexual – schizogony – schizogonic cycle Sexual – sporogony – sporogonic cycle Female – macrogametes Male - microgametes
A. SARCOCYSTIS SPP.S. HOMINIS, S. SUIHOMINIS, & S. LINDEMANNI
General Characteristics Infect humans (DH) and animals (IH) Sarcosporidiosis or sarcocystosis - infection Spread throughout various organs and tissues MOT – ingestion of uncooked or undercooked meat containing the SARCOCYSTS Infective Stage: Human – SARCOCYSTS IH - SPOROCYSTS
Parasite Biology Zoite – simplest form Banana-shaped cell Pointed end – equipped for entering the host cells Sporocyst = 4 zoites sporozoites Sarcocyst = formed from sporozoites Asexual cycle – occurs in IH Sexual cycle – occurs in DH
Parasite Biology (contd.) S. hominis S. suihominis IH cattle swine DH human humanSporocyst bigger smaller Effect Intestinal Intestinal sarcocystosis sarcocystosis
Pathology & Clinical Manifestation Gastroenteritis with diarrhea Eosinophilic enteritis Myalgia Weakness Mild increase of creatine kinase
Diagnosis Fecal flotation method – sporocysts 9-16um in length Oblong or cylindrical 4 long teardrop-shaped sporozoites Western blot IFA and ELISA
Treatment & Prevention No effective treatment is known Corticosteroid – treat muscular inflammation Trimethoprim-sulfamethoxazole – treat intestinal infections “Cook the meat well before eating!!!”
Parasite Biology Cryptosporidiosis – infection Causes severe diarrhea (immunocompromised) and transient diarrhea (healthy persons) Water-borne transmission – is the most common source of this infection MOT: ingestion of oocysts IS: oocysts containing sporozoites 1 oocyst = 4 sporozoites Oocyst = 4 to 5 um Watch this!
C. Toxoplasma gondii A PARASITE OF COSMOPOLITAN DISTRIBUTION
General Characteristics House Cat – definitive host MOT – consumption or handling of infected meat or from contact with cat feces IS – oocysts Cysts – found in muscles and CNSWatch the video here I’m cute but deadly!!!
Parasite Biology Oocyst = 2 sporocysts, each encloses 4 sporozoites (passed in the feces) Similarin appearance to those of Isospora belli but smaller Trophozoites – found in the mesenteric lymph nodes and other organs of the cat Tachyzoites – multiply quickly and spread the infection Bradyzoites – slow-developing and form cysts
Pathogenesis & Clinical Manifestations Toxoplasmosis – commonly asymptomatic Cysts – can be found in the brain, skeletal and heart muscles, and retina Encephalitis, myocarditis & focal pneumonia – immunocompromised Stillbirth & abortion – 1st trimester of pregnancy Congenital toxoplasmosis
Diagnosis Examination of tissue imprints stained with Giemsa Sabin-Feldman methylene blue dye test – detect Ab against T. gondii Biopsy PCR ELISA Latex Agglutination Test
Treatment & Prevention Pyrimethamine + sulfadiazine – for 1 month -To keep under control but do not kill it Cook food well Pregnant women should avoid contact with cats Avoid unpasteurized milk
D. EIMERIA SPP.RESPONSIBLE FOR THE POULTRY DISEASE COCCIDIOSIS
General Characteristics 4 sporocysts , each containing 2 sporozoites Causes bloody diarrhea E. tenella E. maxima E. necatrix E. fraterculae
General Characteristics I. hominis I. belli Other name Cytospermium hominis Cytospermium intestinalis Oocyst shape Oblong papaya Layer Double-layer One layerPresence of microphyle yes no sporocysts 2 2 sporozoites 4 4 Host Men Men MOT Ingestion of oocyst Ingestion of oocyst
F. PLASMODIA SPP. THE GENUS THAT CAUSES MALARIA
MALARIA Is still considered the most important parasitic disease affecting man, responsible for 1.5 to 2.7 million deaths annually One of the three major infectious disease threats, along with HIV and tuberculosis (WHO) Transmitted by the bite of an infected female Anopheles mosquito A protozoan disease caused by members of the genus Plasmodium characterized by recurring fever, chills and sweats.
MALARIA (contd.) P. falciparum responsible for over 90% P. vivax of all the cases of human malaria P. ovale P. malariae Pigment producers – malarial parasites feed on Hgb Ameboid in shape
Parasite Biology Asexual Cycle Sexual Cycle Human (IH) Anopheles mosquito (DH) Schizogony merozoites Sporogony sporozoitesGametogony gametocytes MOT: bite of vectors & blood transfusion
Parasite Biology (contd.)• life cycles of all four human species of malaria are similar• sporozoites – infective stage to human • Injected to human and carried to the liver• Merozoites – enter the rbc - Develop into microgametocytes (male) and macrogametocytes (female) which are picked up by the mosquito for completion of the cycle• Hypnozoites – produced by P. vivax and P. ovale ; resting stage• Trophozoites – developed in the rbc
Exo-erythrocytic Stage sporozoites enters hepatocytes of liver schizonts dividing forms of liver stages merozoites are released by hepatocytes hypnozoites resting liver stages
Blood Stages merozoites enter erythrocytes trophozoites feeding and growing stages in red cells schizonts multinuclear stages in red cells gametocytes sexual blood stages
1. early trophozoite 2. early trophozoite (double infection) 3. early trophozoite double chromatin with a few Maurers dots4. late throphozoite with Maurers dots and crenated red cell5. Mature schizont with merozoites and clumped pigment6. macrogametocyte with bluish cytoplasm and compact chromatin7. microgametocyte with pinkish cytoplasm and dispersedchromatin. Watch the life cycle
Pathogenesis & Clinical Manifestations P. P.vivax P. ovale P. malariae falciparumOther name Malignant Benign tertian Ovale malaria Quartan tertian or malaria malaria subtertian malaria Pre-patent 11-14 days 11-15 days 14-26 days 3-4 weeks period Incubation 8-15 days 12-20 days 11-16 days 18-40 days periodErythrocytic 48 hours 48 hours 48 hours 72 hours Cycle Chromatin Maurer’s Schuffner’s Schuffner’s Zieman’s dots (coarse red (fine red granules) granules)
P. P.vivax P. ovale P. malariae falciparumtrophozoite Ring & comma Signet-ring Ring to Band form forms shape roundedgametocytes Banana- Oval Round Round shapedMerozoites 8-40 12-24 14-16 6-12 Schizont Single dark Loose mass Concentrated concentrated pigment mass mass
Pathogenesis & Clinical Manifestations (contd.) Regular Paroxysms of fever with asymptomatic intervals Prodromal symptoms Weakness and exhaustion Desire to stretch and yawn Aching bones, limbs and back Loss of appetite Nausea and vomiting Sense of chilliness Malaise Diarrhea Epigastric discomfort
3 Stages of Classical Malaria Paroxysm Cold Stage Pressure goes down Chilling Intense headache Loss of appetite Dry skin which lasts for 2-4 hours Goose flesh Convulsion of children which Sweating Stage lasts for 1-2 hours Profuse sweating Temp. Is going up Gradually, temp. Goes down Less intense headache which lasts Hot Stage for 2-5 hours Sensation of great heat Patient feels exhausted until falls Restlessness asleep Pulse is full and pounding Vomiting
Diagnostic Points1. Red Cells are notenlarged.2. Rings appear fine anddelicate and there may beseveral in one cell.3. Some rings may have twochromatin dots.4. Presence of marginal orapplique forms.5. It is unusual to seedeveloping forms inperipheral blood films.6. Gametocytes have acharacteristic crescentshape appearance.However, they do notusually appear in the bloodfor the first four weeks ofinfection.7. Maurers dots may bepresent.
Diagnostic Points1. Red cells containing parasites are usually enlarged.2. Schuffners dots arefrequently present inthe red cells as shownabove.3. The mature ringforms tend to be largeand coarse.4. Developing formsare frequentlypresent.
Diagnostic Points1. Ring forms may have a squarish appearance.2. Band forms are a characteristic of this species.3. Mature schizonts may have a typical daisy head appearance with up to ten merozoites.4. Red cells are not enlarged.5. Chromatin dot may be on the inner surface of the ring.
DiagnosticPoints1. Red cells enlarged.2.Comet formscommon (topright).3. Rings largeand coarse.4. Schuffnersdots, whenpresent, may beprominent.5. Matureschizonts similarto those of P.malariae butlarger and morecoarse
Treatment & Prevention Chloroquine – treatment of choice Sulfadoxine-pyrimethamine or quinine – alternative for chloroquine-resistant Artemisinin and derivatives Use mosquito nets Use insect repellants Wear light-colored clothing