Advertisement

Comparison of direct immunofluorescence, modified acid-fast staining, and enzyme immunoassay techniques for detection of Cryptosporidium spp in naturally exposed kittens

View More View Less
  • 1 Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California, Davis, CA 95616.
  • | 2 Department of Mathematics and Statistics, College of Arts and Sciences, University of New Mexico, Albuquerque, NM 87131.
  • | 3 Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California, Davis, CA 95616.

Abstract

Objective—To evaluate a modified Ziehl-Neelsen acid-fast staining technique (mZN), a direct immunofluorescence detection procedure (DIF), and 3 commercial enzyme immunoassays (EIAs) for detection of Cryptosporidium oocysts in fecal specimens from kittens.

Design—Prospective study.

Sample Population—416 fecal specimens collected from 104 randomly selected domestic shorthair kittens (8 to 16 weeks of age) that were naturally exposed to Cryptosporidium spp.

Procedure—Fresh fecal specimens were collected once daily for 4 consecutive days and processed immediately. Sensitivities of mZN, DIF, and 3 commercial EIAs (EIA-1, EIA-2, and EIA-3) were estimated and compared.

Results—EIA-2 had the highest sensitivity on day 1 (89%), followed by EIA-1 (80%), and mZN (72%). EIA- 3 had the lowest sensitivity on day 1 (15%). EIA-2, EIA- 1, and mZN had similar sensitivities after 2 consecutive fecal examinations (approx 90%). Determination of specificities was compromised by the small number of cats that had negative results for all tests (n = 3).

Conclusions and Clinical Relevance—Results suggest that EIA-2 and EIA-1 had the highest sensitivities when only a single fecal specimen was examined; however, mZN and EIA-1 had similar sensitivities when 2 consecutive fecal specimens were examined. The higher costs of EIA-2 and EIA-1 may be offset by the tests’ high sensitivity, simplicity of use, and ease of interpretation and by savings in technician time. (J Am Vet Med Assoc 2004;225:1549–1553)

Abstract

Objective—To evaluate a modified Ziehl-Neelsen acid-fast staining technique (mZN), a direct immunofluorescence detection procedure (DIF), and 3 commercial enzyme immunoassays (EIAs) for detection of Cryptosporidium oocysts in fecal specimens from kittens.

Design—Prospective study.

Sample Population—416 fecal specimens collected from 104 randomly selected domestic shorthair kittens (8 to 16 weeks of age) that were naturally exposed to Cryptosporidium spp.

Procedure—Fresh fecal specimens were collected once daily for 4 consecutive days and processed immediately. Sensitivities of mZN, DIF, and 3 commercial EIAs (EIA-1, EIA-2, and EIA-3) were estimated and compared.

Results—EIA-2 had the highest sensitivity on day 1 (89%), followed by EIA-1 (80%), and mZN (72%). EIA- 3 had the lowest sensitivity on day 1 (15%). EIA-2, EIA- 1, and mZN had similar sensitivities after 2 consecutive fecal examinations (approx 90%). Determination of specificities was compromised by the small number of cats that had negative results for all tests (n = 3).

Conclusions and Clinical Relevance—Results suggest that EIA-2 and EIA-1 had the highest sensitivities when only a single fecal specimen was examined; however, mZN and EIA-1 had similar sensitivities when 2 consecutive fecal specimens were examined. The higher costs of EIA-2 and EIA-1 may be offset by the tests’ high sensitivity, simplicity of use, and ease of interpretation and by savings in technician time. (J Am Vet Med Assoc 2004;225:1549–1553)