environmental assay data sheet

Cystoisospora belli / Isospora belli PCR test

Test code: X0041 - Ultrasensitive qualitative detection of Cystoisospora belli / Isospora belli by real time PCR

Isospora belli, recently renamed as Cystoisospora belli, is a single-celled protozoan parasite belonging to the coccidian group that infects the epithelial cells of the small intestine in humans. It causes an intestinal disease called cystoisosporiasis (or isosporiasis), which is transmitted through the fecal-oral route, typically via ingestion of contaminated food or water containing mature oocysts. This parasite has a global distribution but is more prevalent in tropical and subtropical regions, and it primarily affects immunocompromised individuals, such as those with HIV/AIDS, though infections can sometimes occur in immunocompetent people as well.

Humans infected with this parasite may develop watery diarrhea, abdominal cramps, nausea, vomiting, low-grade fever, and weight loss. In severe cases, especially among those with weakened immune systems, it can cause prolonged diarrhea, malabsorption, and dehydration. Symptoms typically appear 1-2 weeks after ingestion and can last for weeks to months if untreated.

Prevention of infection involves good hygiene practices, such as handwashing, clean drinking water, and proper food handling to avoid fecal contamination. In areas with poor sanitation, boiling water or using filters can help reduce risk.

Cystoisospora belli has a direct life cycle, completing all stages in a single host without needing an intermediate host. Traditionally, diagnosis was usually made by identifying the parasite's distinctive oocysts in stool samples under a microscope using special stains like acid-fast staining. However, microscopy can miss low-level infections because oocyst shedding is often intermittent, requires experienced lab personnel for accurate interpretation, and may yield false negatives in cases with sparse parasites. Polymerase chain reaction (PCR) is frequently employed for diagnosing Cystoisospora belli infections due to its superior sensitivity and specificity (Basyoni et al., 2017; ten Hove et al., 2008).

Utilities:

• Check for Cystoisospora belli in water sources and other environmental samples
• Selection of appropriate remediation regimens
• Check for post-remediation absence of this agent
• Help confirm the presence of this agent in cultures
• Help minimize human exposure to this agent

References:

Basyoni MMA, Elghobary HAF. Genotypic Identification of Cystoisospora in Immunocompromised Patients Using Tm-Variation Analysis. Korean J Parasitol. 2017 Dec;55(6):601-606.

ten Hove RJ, van Lieshout L, Brienen EA, Perez MA, Verweij JJ. Real-time polymerase chain reaction for detection of Isospora belli in stool samples. Diagn Microbiol Infect Dis. 2008 Jul;61(3):280-3.

Specimen requirements: 2 ml of water, or used water filter media; or environmental swab or swipe, or 0.2 ml culture.

Contact Zoologix if advice is needed to determine an appropriate specimen type for a specific diagnostic application. For specimen types not listed here, please contact Zoologix to confirm specimen acceptability and shipping instructions.

For all specimen types, if there will be a delay in shipping, or during very warm weather, refrigerate specimens until shipped and ship with a cold pack unless more stringent shipping requirements are specified. Frozen specimens should be shipped so as to remain frozen in transit. See shipping instructions for more information.

Turnaround time: 2 business days

Methodology: Qualitative real time polymerase chain reaction

Normal range: Nondetected