Cyclospora cayetanensis medical parasitology

This topic is for the medical laboratory subject called medical parasitology

1. Cyclospora cayetanensis

2. Introduction: Cyclospora cayetanensis is a microscopic parasite that causes cyclosporiasis , an intestinal illness that can affect both immunocompetent ( having a normal immune response .)and immunocompromised (immunodeficiency : is  a condition where the body's immune system is weakened, making it harder to fight off infections and cancer . )people

3. Prevalence: The global prevalence of Cyclospora cayetanensis in humans is estimated to be 3.55%. However, the prevalence varies by region and population:  Low-income countries : The prevalence is higher in low-income countries than in upper-middle-income and high-income countries.  Africa : Africa has the highest prevalence rate at 5.9%.  Children : Children are more susceptible to C. cayetanensis infection than adults. 

4. Immunocompromised individuals :  In low-resource endemic areas, immunocompromised individuals are more likely to be diagnosed with cyclosporiasis .  Endemic: (of a disease) regularly occurring within an area or community. Pendemic : A pandemic is when a new disease or new strain of an existing disease spreads worldwide.

5. Geographical distribution: Cyclospora cayetanensis is a parasite that causes prolonged diarrhea in humans and is found in many countries around the world, but is most common in tropical and subtropical regions:  Regions : The parasite has been reported in North, Central, and South America, the Indian Subcontinent, Southeast Asia, and Australia.  Endemic areas : Peru, Haiti, and Nepal are considered high endemic areas.  Outbreaks : The first recorded outbreak of C. cayetanensis in humans was in Nepal in 1989. The first reported outbreak in the United States was in 1990.

6. Mode of infection: Cyclospora cayetanensis , a microscopic parasite, is transmitted through the fecal-oral route, meaning that people become infected by consuming food or water contaminated with feces that contains the parasite

7. Habitat: Cyclospora cayetanensis is found in tropical and subtropical regions, and is endemic in many developing countries. It can be found in the environment in water, soil, and wildlife feces.  Cyclospora cayetanensis can be transmitted to humans through contaminated food or water. The parasite needs to be in the environment for about 1 to 2 weeks after being passed in stool to become infectious. 

8. life cycle:

9. When freshly passed in stools, the oocyst is not infective    (thus, direct fecal-oral transmission cannot occur; this differentiates   Cyclospora  from another important coccidian parasite,  Cryptosporidium ). In the environment   , sporulation occurs after days or weeks at temperatures between 22°C to 32°C, resulting in division of the sporont into two sporocysts , each containing two elongate sporozoites    . The sporulated oocysts can contaminate fresh produce and water   which are then ingested  . The oocysts excyst in the gastrointestinal tract, freeing the sporozoites , which invade the epithelial cells of the small intestine 

10. . Inside the cells they undergo asexual multiplication into type I and type II meronts . Merozoites from type I meronts likely remain in the asexual cycle, while merozoites from type II meronts undergo sexual development into macrogametocytes and microgametocytes upon invasion of another host cell. Fertilization occurs, and the zygote develops to an oocyst which is released from the host cell and shed in the stool   . Several aspects of intracellular replication and development are still unknown, and the potential mechanisms of contamination of food and water are still under investigation.

11. Pathogenesis: The pathogenesis of Cyclospora cayetanensis , the microscopic parasite that causes cyclosporiasis , involves the following steps: Ingestion : The infection begins when a person ingests oocysts that are contaminated with feces in food or water. Excystment : The oocysts excyst in the small intestine. Invasion : The sporozoites invade the epithelial cells of the duodenum and jejunum.

12. Trophozoite formation : The sporozoites develop into trophozoites . Meront formation : The trophozoites develop into either Type I or Type II meronts . Sexual cycle : Type II meronts develop into microgametocytes and macrogametocytes , which fertilize to form a zygote. Oocyst formation : The zygotes develop into oocysts in the enterocytes , and are then shed in the feces.  The oocysts have a thick bilayered wall that allows them to survive in harsh environmental conditions, including chlorination.  The infection causes inflammation, reactive vascular changes, and partial atrophy of the intestinal villi . This disrupts the intestinal barrier and leads to malabsorption . Symptoms include: watery diarrhea, abdominal pain, nausea, anorexia, weight loss, and low-grade fever.  The antiparasitic treatment of choice is trimethoprim-sulfamethexole .  Risk factors for infection include: Contact with animals, Being a resident foreigner or traveler to endemic areas, and Consuming contaminated food. 

13. laboratory diagnosis: Cyclospora cayetanensis , a protozoan parasite that causes diarrheal illness, can be detected in a laboratory using a variety of methods, including: Microscopic examination A stool sample is examined under a microscope for the presence of oocysts , which are spherical and about 8–10 µm in diameter.  Oocysts can be stained using modified Ziehl-Neelsen or Kinyoun acid-fast stains, or a modified safranin stain that produces a consistent reddish-orange color.  UV fluorescence microscopy A more sensitive and specific method than acid-fast staining, but requires a fluorescence microscope with a special filter.  Oocysts of C. cayetanensis are autofluorescent and appear blue under UV light.  Molecular testing A DNA-based test that can detect the presence of C. cayetanensis in stool samples. The multiplex Biofire FilmArray Gastrointestinal Panel is one commercially available option. 

14. prevention and control of: To prevent and control cyclospora cayetanensis , you can: Practice good hygiene Wash your hands with soap and water often, especially after using the bathroom, before and during preparing food, and after touching feces.  Avoid contaminated food and water Avoid food or water that may have been contaminated with feces, especially in tropical or subtropical areas. 

15. Wash fruits and vegetables Wash all fruits and vegetables thoroughly under running water before eating, cutting, or cooking. Scrub firm fruits and vegetables with a clean produce brush.  Refrigerate fruits and vegetables Refrigerate cut, peeled, or cooked fruits and vegetables as soon as possible (within two hours).  Cook food thoroughly Make sure to cook all foods all the way.  There is no vaccine for cyclosporiasis , and routine chemical disinfection or sanitizing methods are unlikely to kill it.