Related Experiment Video
Updated: Sep 26, 2026
Development of a Quantitative Recombinase Polymerase Amplification Assay with an Internal Positive Control
Published on: March 30, 2015
Polymerase chain reaction for the detection of Cryptosporidium spp. in cat feces
A V Scorza1, M M Brewer, M R Lappin
1Department of Clinical Sciences, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, Colorado 80523, USA. vscorza@lamar.colostate.edu
Abstract:
The objective of this study was to compare a polymerase chain reaction (PCR) assay and a monoclonal antibody-based immunofluorescence assay (IFA) for detection of Cryptosporidium parvum in cat feces. Eight C. parvum-naive DSH cats were orally inoculated with 1 x 10(6) oocysts of a C. parvum human isolate. Fecal samples were collected before inoculation, daily for the next 30 days, and twice weekly until day 85. Methylprednisolone acetate was administered at 20 mg/kg i.m. on days 85, 92, and 99. From days 86 to 115, feces were collected daily and then up to twice weekly until day 126. Immunofluorescence assay was performed after collection of the samples, and then the samples were frozen at -70 C until assayed by PCR. Cryptosporidium parvum was detected by PCR in 101 of 353 samples and by IFA in 52 of 353 samples: 27 samples were PCR positive, IFA positive; 74 samples were PCR positive, IFA negative; 25 samples were PCR negative, IFA positive; and 227 samples were PCR negative, IFA negative. The percentage of concordance between IFA and PCR was 72%. Results of this study suggest that this PCR assay is more sensitive than IFA for detection of C. parvum in cat feces.
Insights
A new polymerase chain reaction (PCR) assay is more sensitive for detecting Cryptosporidium parvum in cat feces than the traditional immunofluorescence assay (IFA). This PCR method offers improved diagnostic accuracy for feline cryptosporidiosis.
Area of Science:
- Veterinary Parasitology
- Molecular Diagnostics
- Feline Infectious Diseases
Background:
- Cryptosporidium parvum is an opportunistic protozoan parasite that can cause gastrointestinal disease in cats.
- Accurate detection of C. parvum in feline fecal samples is crucial for diagnosis and management.
- Current diagnostic methods like immunofluorescence assay (IFA) may have limitations in sensitivity.
Purpose of the Study:
- To compare the diagnostic sensitivity and specificity of a polymerase chain reaction (PCR) assay against a monoclonal antibody-based immunofluorescence assay (IFA) for detecting C. parvum in cat feces.
- To evaluate the efficacy of PCR in identifying C. parvum oocysts in feline fecal samples under experimental conditions.
Main Methods:
- Eight C. parvum-naive cats were inoculated with C. parvum oocysts.
- Fecal samples were collected over a 126-day period, including periods of immunosuppression induced by methylprednisolone acetate.
- Samples were analyzed using both IFA and PCR assays, with IFA performed immediately and PCR after frozen storage.
Main Results:
- Polymerase chain reaction (PCR) detected C. parvum in 101 of 353 samples, while immunofluorescence assay (IFA) detected it in 52 of 353 samples.
- The concordance between IFA and PCR was 72%.
- PCR identified 74 samples as positive that were negative by IFA, indicating higher sensitivity.
Conclusions:
- The developed PCR assay demonstrates significantly higher sensitivity for detecting C. parvum in cat feces compared to the IFA.
- PCR offers a more reliable diagnostic tool for identifying feline cryptosporidiosis, especially in low oocyst shedding or post-treatment scenarios.
- Further validation of PCR assays is recommended for routine veterinary diagnostics of parasitic infections.
