Clinical Parasitology - Coccidian Parasites PDF

PARA311: CLINICAL PARASITOLOGY TOPIC: COCCIDIAN PARASITES 1ST SEMESTER | S.Y 2024-2025 LECTURER: Prof. Rose Dyane Hizola, RMT, MPH TOPIC Immature ooc...

PARA311: CLINICAL PARASITOLOGY TOPIC: COCCIDIAN PARASITES 1ST SEMESTER | S.Y 2024-2025 LECTURER: Prof. Rose Dyane Hizola, RMT, MPH TOPIC Immature oocyst seen in the feces of patients contain SUBTOPIC two sporoblasts. SUB SUBTOPIC The oocysts mature outside the body. On maturation, the sporoblast convert into sporocysts. Each sporocyst contain 4 crescent shaped sporozoites COCCIDIAN PARASITES Infective stage: Sporulated oocyst containing 8 sporozoites is of the parasite Unicellular protozoans that is under class Sporozoa Mode of transmission: ingestion of food and water (Phylum Apicomplexa) contaminated with sporulated oocysts or mature cyst - Group of microscopic, spore-forming, unicellular, obligate intercellular protozoans Intercellular protozoans; some of their life cycle, they live inside the cells They are intestinal coccidians In class Sporozoa, the life cycle is characterized by an alternations of generation: 1. Sexual: Sporogony 2. Asexual: Schizogony Cystoisospora belli Immature cysts: contains two sporoblasts Cryptosporidium hominis When these sporoblasts develop, these will become Cyclospora cayetanensis sporocysts Toxoplasma gondii Inside the sporocyst, it will have 4 crescent shaped Sarcocystis hominis and Sarcocystis suihominis sporozoites [4-curved sausage-like known as The alternating sexual phase are characterized by three sporozoites – mature stage] (3) sequential stages: 1. Sporogony – sexual cycle that produces the oocysts 2. Schizogony or merogony – asexual phase that produce that merozoites the merons 3. Gametogony – results of the development of male and female gametocytes [Plasmodium spp. gametocytes] Cystoisospora belli formerly known as Isospora belli – parasites of the epithelium cells of the intestines MORPHOLOGY Oocysts of Cystoisospora belli are elongated ovoid and measure 24 um x 15 um. Immature oocysts are released from the intestinal walls Each oocysts is surrounded by a thin, smooth, 2- in the form of feces layered cyst wall 1|Page J.M.J.R.  - That stool will mature into oocysts that have TREATMENT sporozoites Asymptomatic: bland diet and bed rest [water - Maturation from immature oocysts to mature therapy for hydration and bland diet (meaning soft, oocysts will take about 4-5 days not spicy, and not rich in fiber foods)] Mature oocysts that have sporozoites will be ingest by Symptomatic: Trimethoprim-sulfamethoxazole [3 the human host weeks ‘tog binibigay for positive cases] - Ex. Contaminated water or food have contaminated PREVENTION AND CONTROL oocysts and ingested, it will enter the body of the Good sanitary practices host [excystation in the small intestine] Thorough washing and cooking of food Provision for safe drinking water Inside the body, in the small intestine, the sporozoites will undergo another asexual cycle to form merozoites - Merozoites will invade new epithelial cells to Cryptosporidium hominis continue the asexual multiplication - Some merozoites will undergo gametogony Cryptosporidium hominis are minute coccidian parasites [fertilization] [small parasites; they are know to infect the humans - Then, new oocysts will be formed and some of the mammals] - That oocysts when released from the body, could Oocysts of the C. hominis is the infective stage ingest another susceptible host The oocyst is spherical or oval and measures about 5 μm in diameter. PATHOLOGY Oocysts does not stain with iodine and is acid fast. Infection is usually asymptomatic Thin-walled oocysts are responsible for autoinfection. Symptomatic: diarrhea, fever, malaise, abdominal Both thin walled and thick-walled oocyst contain 4 pain and flatulence crescent-shaped sporozoites. Disease is common to children and male homosexuals with AIDS In AIDS patients, reports on dissemination of parasite to other organs are present. - They are affected with this parasites because there are reported cases that this parasite travel to different organs besides the small intestines DIAGNOSIS Direct microscopy For the diagnosis, direct microscopy or microscopic examination using iodine [makikita ang oocysts]; difficult to examine kasi transparent sila Concentration technique (FECT, ZnSO4 and sugar floatation) - We can do the concentration technique; the zinc sulfate method, sugar floatation [most sensitive and most accurate method for detecting isospora belli], and the formalin ether concentration technique Staining techniques (Iodine, Kinyoun, Auramine- Rhodamine) Enterotest and duodenal aspirate Molecular testing or PCR 2|Page J.M.J.R.  MORPHOLOGY One person to another: infected food handlers Infective Stage: oocyts Nosocomial infection DIAGNOSIS Sheather’s sugar floatation, Zinc sulfate floatation technique and Formalin ether/ethyl acetate concentration technique Kinyoun’s modified acid-fast stain (oocyst appear as red-pink doughnut-shaped circular organisms): cheapest and simplest method of diagnosis IFA [Indirect Fluorescent Assay] DNA probe TREATMENT No acceptable treatment yet Supportive therapy with fluid, electrolytes, and nutrient replacement. Nitazoxanide is said to be effective in preliminary studies Bovine colostrum, paromomycin and clarithromycin: treatment of severe diarrhea PREVENTION AND CONTROL Chlorination is not effective Use of multiple disinfectant and combined water treatment Proper disposal of human and animal excreta When ingested, the sporozoites attach to the surface of epithelial cells of the gastrointestinal tract Cyclospora cayetanensis Develop into small trophozoites These trophozoite will divide through schizogony to The oocyst is a non-refractile sphere, measuring 8– produce merozoites 10μm in diameter. It contains 2 sporocysts. Eventually, merozoites will develop into gametocytes Each sporocyst contains 2 sporozoites. Hence, each [zygote] sporulated oocyst contains 4 sporozoites Almost the same as cryptosporidium; known for watery Zygote will produce oocysts [result of the zygotes] diarrhea Thin-walled oocysts will infect intestinal cells and the thick-walled oocysts will pass through the feces MORPHOLOGY Infective Stage: oocyts PATHOLOGY Disease is usually self-limiting Immunocompetent: self-limiting diarrhea within 2-3 MOT: ingestion weeks Immunocompromised: severe diarrhea, bile duct and gallbladder maybe heavily infected, blunted intestinal villi, varying degrees of malabsorption and excessive fluid loss AIDS patient: severe form of diarrhea, progressively worse and life-threatening SOURCES OF INFECTION Faulty water purification system Swimming in contaminated recreation water 3|Page J.M.J.R.  - Lasts up to 3 weeks; no deaths associated with this parasite - Self-limiting; may last up to several weeks - Associated with AIDS patients DIAGNOSIS DFS Concentration techniques Kinyoun stain Fluorescent microscopy Safraning staining PCR TREATMENT No treatment needed If pharmacologic treatment is warranted, cotrimoxazole is given. If diarrheal symptoms are prominent, either metronidazole or iodoquinol can be used. PREVENTION AND CONTROL Good sanitary practices Access to safe and clean drinking water Proper food preparation Toxoplasma gondii MORPHOLOGY Infective Stage: trophozoite (tachyzoite), tissue cyst (bradyzoite) and the oocyst - Infect different vertebra or vertebrae host - Occurs in domestic cats [feline family] Definitive host: Cats (complete life cycle occurs in cats) - Support shizogony and gametogony A. Unsporulated oocyst – cannot differentiate the Clinical manifestation is apparent if immune system is cytoplasm; 2 immature sporocysts suppressed. B. Oocysts that mechanically ruptured C. Free or released sporocysts; 2-phase sporozoites D. Oocysts Under the UV light, it will appear bluish green or bluish circle – important characteristic or criteria for identifying Cyclospora cayetanensis [autofluorescent criteria] PATHOLOGY Chronic and intermittent watery diarrhea occurs in early infection and may alternate with constipation. Fatigue, anorexia, weight loss, nausea, abdominal pain, flatulence, bloating and dyspnea may develop. Infections are usually self-limiting. No death is associated. 4|Page J.M.J.R.  - The bradyzoite are release in the small intestine and will undergo multiple asexual multiplication leading to formation of merozoite. - Some of the merozoites they enter in intestinal tissues resulting to formation of tissue cyst and other merozoites transform in male and female gametocytes and formation of macrogametes and microgametes begin. - After the fertilization of gametocytes, it will result to mature oocyst containing sporozoite that is infective to human. Exoenteric Cycle occurs in the humans - Only the tissue cyst and tachyzoite are exhibited by intermediate host including the humans. The sporozoite from the oocyst and the bradyzoite from tissue cyst enter intestinal mucosa and multiply asexually and the tachyzoite are form. The tachyzoite are spread to distant extra-intestinal organ like brain, eyes, and other nature organ. Here, producing two (2) stages, tachyzoite and bradyzoite. PATHOLOGY Toxoplasmosis commonly asymptomatic, if immune system is good. Active progression of infection is more likely in immunocompromised individuals. is the most common manifestation. CONGENITAL TOXOPLASMOSIS Results when T. gondii is transmitted transplacentally from mother to fetus. Most infected newborns are asymptomatic at birth and may remain so throughout. Some develop clinical manifestations of toxoplasmosis weeks, months, and even years after birth. Enteric Cycle: occurs in the definitive host which are Manifestations: chorioretinitis, cerebral calcifications, cats convulsions, strabismus, deafness, blindness, mental - Both sexual reproduction (gametogony) or asexual retardation, microcephaly, and hydrocephalus. reproduction (schizogony) occur in the mucosal ACQUIRED TOXOPLASMOSIS epithelial of the small intestine of the cats. Infection acquired postnatally is mostly - The life cycle is complete, there is sexual and asymptomatic. asexual reproduction. he most common manifestation of acute acquired - The cat will acquired the infection if they have toxoplasmosis is lymphadenopathy; the cervical eaten rats that infected with tissue cyst or directly lymph nodes being most frequently affected. digested the oocyst. 5|Page J.M.J.R.  IMAGING Magnetic resonance imaging (MRI) and computed tomography (CT) scan are used to diagnose toxoplasmosis with central nervous system involvement. Ultrasonography (USG) of the fetus in utero at 20–24 OCULAR TOXOPLASMOSIS weeks of pregnancy is useful for diagnosis of It may present as uveitis, choroiditis, or chorioretinitis congenital toxoplasmosis. TOXOPLASMOSIS IN IMMUNOCOMPROMISED PATIENTS Most serious and often fatal in immunocompromised TREATMENT patients, particularly in AIDS, whether it may be due to reactivation of latent infection or new acquisition Congenital toxoplasmosis: pyrimethamine and of infections. sulfadiazine Ocular toxoplasmosis: pyrimethamine plus either sulfadiazine or clindamycin. DIAGNOSIS Immunocompromised patients: Trimethoprim MICROSCOPY sulfamethoxazole is the drug of choice, dapsone- Tachyzoites and tissue cysts can be detected in pyrimethamine is the recommended alternative drug of various specimens like blood, sputum, bone marrow choice aspirate, cerebrospinal fluid (CSF), amniotic fluid, and biopsy material from lymph node, spleen, and brain. PREVENTION AND CONTROL Smear made from above specimens is stained by Good sanitation and hygiene Giemsa, PAS, or Gomori methenamine silver (GMS) stain. Tachyzoites appear as crescent shaped Proper food preparation structures with blue cytoplasm and dark nucleus Pregnant women should avoid contact with cats ANTIBODY DETECTION Acute infection with T. gondii can be made by detection of the simultaneous presence of IgM and Sarcocystis hominis and Sarcocystis suihominis IgG antibodies. Tests for detecting IgG antibody include: Enzyme Sarcocystis species produce cyst in the muscle of the linked immunosorbent assay (ELISA), Indirect intermediate hosts. These cysts, called Sarcocysts, fluorescent antibody test (IFAT), Latex agglutination contain numerous bradyzoites test and Sabin Feldman dye test ANTIGEN DETECTION Detection of antigen by ELISA indicates recent Toxoplasma infection. Useful in AIDS and other immunocompromised patients. Detection in amniotic fluid is helpful to diagnose congenital toxoplasmosis SKIN TEST OF FRENKEL Diluted toxoplasmin is injected intradermally and delayed positive reaction appears after 48 hours. This test is not very reliable for diagnosis of toxoplasma. MOLECULAR METHODS DNA hybridization techniques and polymerase chain reaction (PCR) are increasingly used to detect Toxoplasma from different tissues and body fluids 6|Page J.M.J.R.  DIAGNOSIS Fecal floatation methods: sporocysts will be seen Demonstration of sarcocysts in the skeletal muscle and cardiac muscle by biopsy or during autopsy. Western blot Serologic tests (IFA, ELISA) PCR TREATMENT No specific treatment is available for sarcocystosis. Corticosteroids were found to be useful in muscular inflammation Trimethoprim-sulfamethoxazole is seen as potentially effective in treating intestinal infections PREVENTION AND CONTROL Uncooked animal carcass should not be fed to other animals Avoiding eating raw or undercooked beef or pork Thoroughly cooking and freezing meat to kill bradyzoites When the Sarcocystis eaten by definitive host, the merozoite are release in intestine where they develop male and female gametocyte. After the fertilization, the zygote develops an oocyst containing 2 sporocyst, each having 4 sporozoites insides. These oocysts are shed in the feces and are ingested by the intermediate host. This are already mature oocyst; they readily infect the susceptible host. Once it gets by intermediate host such as cows and pigs, the sporocyst will rapture, releasing the sporozoite and enter to endothelial cells of blood vessels and under schizogony. Schizont rapture releasing the merozoite and merozoite under muscle cells and develop cyst with bradyzoite. Infective and Diagnosis stage: Cyst with bradyzoite ingested in under cook meat or the Sporocyst and Thin- walled oocyst that are pass in the feces PATHOLOGY Sarcosporidiosis and sarcocystosis Gastroenteritis, diarrhea, myalgia, weakness, fever For intermediate host, brain, muscle and kidney tissues maybe damaged. May cause abortion to cows 7|Page J.M.J.R.