From the Guidelines
Parasite testing is crucial for patients with symptoms suggesting a parasitic infection, such as persistent diarrhea, abdominal pain, or unexplained weight loss, and should be performed using a combination of stool ova and parasite examination and molecular testing, as recommended by the Centers for Disease Control and Prevention guidelines 1.
Importance of Parasite Testing
Parasite testing is essential for accurate diagnosis and treatment of parasitic infections. The most common tests include:
- Stool ova and parasite (O&P) examination, which requires collecting 3 stool samples over several days to increase detection rates
- Molecular testing, such as enzyme immunoassay tests (Giardia antigen) or nucleic acid amplification tests like polymerase chain reaction, which are considered gold standard 1
High-Risk Populations
Certain populations are at higher risk of parasitic infections, including:
- Individuals who have traveled to endemic areas
- Immunocompromised patients
- Food handlers
- Men who have sex with men
- People who drink untreated or contaminated water
Testing Recommendations
Healthcare providers should recommend parasite testing for patients with symptoms suggestive of a parasitic infection, and consider pretest probability before ordering these tests 1. Testing is important because different parasites require specific treatments, such as metronidazole (250-750 mg three times daily for 5-10 days) for Giardia, or albendazole (400 mg once daily for 1-3 days) for many intestinal worms 1. Accurate diagnosis ensures appropriate treatment and prevents complications like malnutrition or chronic inflammation.
Diagnostic Approaches
For suspected tissue parasites, serological tests or imaging studies may be necessary 1. Novel multiplex panel tests that evaluate stool samples by polymerase chain reaction for multiple bacteria and/or parasites may also be relevant in high-risk populations, such as recent travel to endemic areas 1.
From the FDA Drug Label
DIAGNOSIS: Diagnosis of E. multilocularis in canids is difficult. The adult tapeworm produces no clinical signs of infection. Tapeworm segments (proglottids) are usually not observed in the feces. E. multilocularis eggs, observed using microscopic fecal examination procedures, are similar in appearance to those of common species such as Taenia pisiformis.
- Parasite testing is done through microscopic fecal examination procedures to observe E. multilocularis eggs.
- Assistance in the diagnosis of E multilocularis may be available from a state veterinary diagnostic laboratory 2.
- A follow-up fecal examination should be conducted 2 to 4 weeks after treatment to determine the need for retreatment.
From the Research
Parasite Testing Overview
- Parasite testing is crucial for diagnosing and managing parasitic infections, such as giardiasis, hookworm, and other intestinal protozoal infections 3, 4.
- The choice of treatment for parasitic infections depends on various factors, including the type of parasite, severity of symptoms, and patient population (e.g., children, adults) 5, 6.
Diagnostic Approaches
- A multi-step diagnostic approach is recommended for parasitic infections, taking into account the differential diagnosis and prioritizing probabilities 5.
- Laboratory tests, such as stool examinations and blood tests, are essential for diagnosing parasitic infections 3, 4.
- Imaging studies, such as X-rays and ultrasound, may also be used to support diagnosis in certain cases 5.
Treatment Options
- Metronidazole is a commonly used treatment for giardiasis, but other drugs like tinidazole, albendazole, and mebendazole may also be effective 3, 7.
- Albendazole is probably equivalent to metronidazole in achieving parasitological cure and improving symptoms, with fewer side effects 7.
- Tinidazole has been shown to be more effective than metronidazole in some studies, with higher parasitological cure rates 3.
- Higher doses of albendazole (e.g., 800 mg) may be more effective against hookworm infections in adults 6.