Comparison of Histopathology, Serology and PCR for the Diagnosis of Malignant Catarrhal Fever

Kim, Ok-jin; Crawford, Timothy B.

Korean Journal of Veterinary Research 2003;43(3):471-476.

¹Department of Agriculture, Animal Disease Research Unit, ARS
²Department of Veterinary Pathology, College of Veterinary Medicine, Washington State University

Malignant Catarrhal Fever의 병리조직학적 진단과 혈청학적 진단 및 PCR 진단법의 비교

김옥진¹, ²

¹미국 농무부 동물질병연구소
²워싱턴주립대학교 수의과대학

Abstract

Malignant catarrhal fever (MCF) is a systemic disease of ruminants caused by ovine herpesvirus 2 (OvHV-2). OvHV-2 is a gamma herpesvirus, which induces frequent latent infection and often difficult to detect its antigens and even specific nucleic acids because of its low viral copies in the infected tissues. Histopathology, serology and polymerase chain reaction (PCR) were compared for the diagnosis of MCF using 10 bison infected with OvHV-2. Histopathological diagnosis was performed using the criteria which was based upon the pathognomic lesions. Serological diagnosis was conducted using its serum with competitive ELISA for the detection of antibodies of OvHV-2. Also, the nest PCR was performed with peripheral blood leukocytes for the detection of OvHV-2-specific DNAs. Primers 556 and 775 were used for the primary amplification, and primers 556 and 555 were used for the secondary amplification. As the results, positive cases were 6 by histopahology, 9 by serology and 10 by PCR. As comparing with other diagnostic methods, PCR was found to be more sensitive than histopathology and serology. The recent development of molecular diagnostic assays has provided powerful tools for investigating how viruses survive in nature. Development of PCR specific for viruses has dramatically improved the accuracy of diagnosis of viruses in clinically infected animals. Furthermore, amplification of viral genomic material by nest PCR represents the most sensitive method for the detection of viruses and might be detected successfully even though very low viral DNA copies. So, it could be used as the first choice for the detection of viral DNAs with low copies such as the status of latent infection. However, it has also some limitation of application like as false negative results by PCR inhibitors and false positive results by contamination. The results of this study suggest that the use of molecular biological methods like PCR may increase the accuracy for the diagnosis of infectious diseases. However, in diagnostic laboratory, it is recommended that PCR assay must be conducted with other diagnostic methods for more reliable diagnosis.

Key Words: histopathology, serology, PCR, diagnosis