Submitted to: International Marek's Disease Symposium Abstracts and Proceedings
Publication Type: Proceedings
Publication Acceptance Date: September 7, 1996
Publication Date: N/A
Technical Abstract: Field diagnosis of MD based upon gross and histological examinations can sometimes be problematic. Previously, we described a PCR assay to detect MDV sequences. To determine whether the PCR assay correlates exactly with the appearance of MD lesions, 1-day-old 151**5x7**1 chickens were inoculated intra-abdominally with 10**3 PFU of JM/102 virus. At various intervals, birds were sacrificed and examined grossly for lesions. Tissues were also harvested for histological analysis. DNA extracted from the tissues was PCR amplified with primers specific for either the gB gene or the 132 bp repeats in the serotype 1 MDV genome. Results indicated that the buffy coat became PCR positive by 5 days and remained positive at least through 29 days. Both thymus and bursa contained the virus at 5 days as well. Except for the liver, all tested tissues from 14 days on generally contained the MDV genome. Histological lesions first appeared at 14 days post-inoculation in the gonads, kidney, liver, and peripheral nerves. In general, there was good correlation between the appearance of lesions and a positive PCR amplification. However, the less than 100% correlation suggests workers should be cautious in solely relying upon PCR to diagnose MD.