This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Reprints and Permissions Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Peter, T. F. Articles by Mahan, S. M. Search for Related Content PubMed PubMed Citation Articles by Peter, T. F. Articles by Mahan, S. M.

 Previous Article  |  Next Article 

Journal of Clinical Microbiology, 01 1995, 166-172, Vol 33, No. 1
Copyright © 1995 by the American Society for Microbiology. All rights reserved.

Development and evaluation of PCR assay for detection of low levels of Cowdria ruminantium infection in Amblyomma ticks not detected by DNA probe

TF Peter, SL Deem, AF Barbet, RA Norval, BH Simbi, PJ Kelly and SM Mahan
University of Florida/USAID/SADC Heartwater Research Project, Causeway, Harare, Zimbabwe.

The sensitivities of a PCR assay and a DNA probe assay were compared for the detection of Cowdria ruminantium in Amblyomma ticks that were fed on C. ruminantium-infected, clinically reacting, and recovered carrier animals. The PCR assay and DNA probe detected infection in 86.0 and 37.0%, respectively, of 100 ticks fed on a febrile animal. In 75 ticks fed on carrier animals, PCR and the DNA probe detected infection in 28.0 and 1.33% of ticks, respectively. This demonstrates that the DNA probe has poor sensitivity for the detection of low levels of infection in ticks and that PCR is necessary for this purpose. The PCR assay had a detection limit of between 1 and 10 C. ruminantium organisms and did not amplify DNA from Ehrlichia canis, which is phylogenetically closely related to C. ruminantium, Theileria parva, or uninfected Amblyomma hebraeum or A. variegatum. PCR detected infection in A. hebraeum and A. variegatum adult ticks infected with one of six geographically different C. ruminantium strains. Amplification was also possible from desiccated ticks and ticks fixed in 70% ethanol, 10% buffered formalin, or 2% glutaraldehyde. The PCR assay supersedes the DNA probe and older detection methods for the detection of C. ruminantium in ticks, particularly those fed on carrier animals, and is suitable for both prospective and retrospective studies which require accurate detection of C. ruminantium in individual ticks. Application of the PCR assay should significantly improve the understanding of heartwater epidemiology, particularly through the determination of field tick infection rates.

This article has been cited by other articles:

• Semu, S. M., Peter, T. F., Mukwedeya, D., Barbet, A. F., Jongejan, F., Mahan, S. M. (2001). Antibody Responses to MAP 1B and Other Cowdria ruminantium Antigens Are Down Regulated in Cattle Challenged with Tick-Transmitted Heartwater. CVI 8: 388-396 [Abstract] [Full Text]  
• Peter, T. F., Barbet, A. F., Alleman, A. R., Simbi, B. H., Burridge, M. J., Mahan, S. M. (2000). Detection of the Agent of Heartwater, Cowdria ruminantium, in Amblyomma Ticks by PCR: Validation and Application of the Assay to Field Ticks. J. Clin. Microbiol. 38: 1539-1544 [Abstract] [Full Text]  
• Roux, V., Raoult, D. (1999). Body Lice as Tools for Diagnosis and Surveillance of Reemerging Diseases. J. Clin. Microbiol. 37: 596-599 [Abstract] [Full Text]  
• Higgins, J. A., Ezzell, J., Hinnebusch, B. J., Shipley, M., Henchal, E. A., Ibrahim, M. S. (1998). 5' Nuclease PCR Assay To Detect Yersinia pestis. J. Clin. Microbiol. 36: 2284-2288 [Abstract] [Full Text]  
• Messick, J. B., Berent, L. M., Cooper, S. K. (1998). Development and Evaluation of a PCR-Based Assay for Detection of Haemobartonella felis in Cats and Differentiation of H. felis from Related Bacteria by Restriction Fragment Length Polymorphism Analysis. J. Clin. Microbiol. 36: 462-466 [Abstract] [Full Text]