MEDICAL PARASITOLOGY ENTOMOLOGY LECTURER SR NORAZSIDA RAMLI Intestinal

MEDICAL PARASITOLOGY & ENTOMOLOGY LECTURER: SR. NORAZSIDA RAMLI

Intestinal Sporozoa Cryptosporidium parvum Isospora belli Cyclospora cayetanensis Sarcocytis species

General characteristics Nonmotile n Obligate intracellular parasites n Having complex life cycle n With alternating sexual and asexual phases n Oocyst containing mature sporozoites n Sporocyst- a sac within certain oocysts containing sporozoites. n

Cryptosporidium parvum Oocyst: - round to slightly oval, 4 -6µm, n mature oocyst: - contains 4 sporozoites surrounded by a thick double layered wall; no sporocyst are visible; dark staining granul are usually apoparent. n Schizont and gametocytes: small, 2 -4µm, are produced during the life cycle, but rarely seen in human specimens. n Cause cryptosporidiosis, zoonotic transmission does occur. n

Life cycle

Transmission Occurs by ingestion of food or water contaminated with infective oocysts n Person to person contact n Distributed worldwide, in most untreated water supplies n Difficult to remove physically n Resistant to many chemicals including chlorine. n Reservoir host: cattle n

Pathogenesis n n n n Causes self-limited diarrhea in immunocompetent individuals Incubation period: one to several weeks. Symptoms: nausea, fever, vomiting, anorexia, abdominal cramps, watery diarrhea, constipation Recovery- dependent on the immune status of the host. Serious in infant- cause of morbidity and mortality Immunocompromised individuals- often suffer severe, intractable diarrhea. Patient with AIDS- becomes progressively worse, does not respond to treatment may cause death, respiratory tract may also be infected.

Laboratory diagnosis n n n Biopsy Microscopic examination Modified acid fast stain Sheather’s sugar flotation method Formalin fixed Giemsa stained smears Immunodiagnostic assay Enzyme linked immunosorbent assay (ELISA) Fluorescent antibody detection methods

Treatment Highly active antiretroviral treatment (HAART) of HIV– for AIDS patient. n Nitazoxanide- non-immunocompromised individuals. n

Prevention Proper water treatment n Good sanitary practice n Treat water supplies with filtration technique, as well as chemicals n Zoonotic transmission may be prevented by reducing or eliminating contact especially of immunocompromised individuals, with animals. n

Isospora belli Oocyst: elliptical or oval, 25 -30µm by 1017µm n Immature oocyst: containing a single central mass. n Mature oocyst: develops 2 sporoblasts, which develop into 2 sporocysts, each containing 4 cigar-shaped sporozoites, surrounded by double layered wall. n

Life cycle

Transmission Occurs by ingestion of water or food containing infective oocysts. n Zoonotic transmission does not occur. n Unprotected sexual activities: – anal-oral sexual. n

Pathogenesis Infection is often asymptomatic and selflimited. n When present, symptoms include: -diarrhea -abdominal pain -Weight loss -anorexia n An increase of infection in AIDS patients has been reported in recent year. n

Laboratory diagnosis n Similar to C. parvum.

Treatment Asymptomatic individuals may not require treatment n Trimethoprim-sulfamethoxazole n Metronidazole n Tetracycline n Pyrimethamine-sulfadiazine n

Prevention Good personal hygiene n Good sanitary conditions n Protected homosexual contact n

Cyclospora cayetanenis n Oocyst: spherical –similar like C. parvum but larger than – 8 -10µm, contains 2 sporocysts, each containing 2 sporozoites.

Life cycle

Transmission n Occurs by ingestion of contaminated food or water.

Pathogenesis n n - Incubation period: 2 to 7 days Clinical manifestation: Diarrhea Myalgia Anorexia Weight loss Fatigue Vomiting “flu-like” symptoms

Laboratory diagnosis Flotation n Microscopy examination – using phase contrast microscopy and electron microscope. n

Treatment n Trimethoprim-sulfamethoxazole

Prevention Good hygiene n Good sanitation practices n Adequate water treatment methods n Thorough washing of fruits and vegetables n

Sarcocytis species S. bovihominis- in cattle n S. suihominis- in pigs n Oocyst: oval, contains 2 sporocysts with 4 cigar-shaped sporozoites, 25 -33µm, sporocyst is similar to C. parvum but larger, bout 9 -16µm, surrounded by doublelayered wall n Sarcocystis “lindemanni” is the term gien to those organisms that may potentially parasitize humans. n

Life cycle

Transmisson Occur by ingestion of improperly cooked meat (containing the sarcocyst form in muscle). n By ingestion of animal feces-contaminated food or water ( oocyst stage in stool). n

Pathogenesis Symptoms: -diarrhea -abdominal pain -weight loss -muscle pain may be associated with the presence of sarcocysts in human striated muscle n Most cases r asymptomatic n

Laboratory diagnosis Microscopy examination n Muscle biopsies histological method n

Treatment No treatment for the muscle form of sarcocytis infection. n Trimethoprim – sulfamethoxazole n Pyrimethamine - sulfadiazine n

Prevention Adequate cooking of meat n Avoidance of contact with animal feces - Prevents infection of humans as intermediate hosts. n