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ARS Home » Research » Publications at this Location » Publication #112913
Title: CO-INFECTION OF SPF CHICKENS WITH MAREK'S DISEASE VIRUS (MDV) AND CHICKEN INFECTIOUS ANEMIA VIRUS: EFFECT OF MDV PATHOTYPE

Author
item MILES, ANDREA - UNIVERSITY OF DELAWARE
item Reddy, Sanjay
item MORGAN, ROBIN - UNIVERSITY OF DELAWARE

Submitted to: Avian Diseases
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/25/2000
Publication Date: N/A
Citation: N/A

Interpretive Summary: Marek's disease (MD), a virus-induced cancer-like disease of chickens, is considered as a major disease problem in commercial poultry. Vaccination has dramatically reduced the incidence of the disease, but very little is known about the basic mechanisms involved in protection induced by vaccines. Chicken infectious anemia (CIA) )infection is caused by a virus, which leads to destruction of blood and immune cells of chicken. Both MD and CIA infections were prevalent in chicken throughout the world. The purpose of this experiment was to determine the effects of co-infection of CIA and MD viruses. We have determined that CIA infections exacerbate the disease causing potential of MD virus. This new information helps explain why we have encountered increased disease causing potential of MD virus in recent years. The information about co-infections with these two viruses will undoubtedly help scientists in academia and industry understand how co-infections can effect the outcome of these economically important infections in chicken, and therefore, lead to the development of more effective vaccines.

Technical Abstract: Both Marek's disease virus (MDV) and chicken infectious anemia virus (CIAV)infections are prevalent in chickens throughout the world. In the past decade, MDV strains with increased virulence (very virulent plus pathotype,vv+MDV) have been isolated. The purpose of this experiment was to determine the effects of co-infection of chickens with CIAV and a vv+MDV isolate. Specific-pathogen-free (SPF) chickens were inoculated at one day post-hatch with RB1B only, 584A only, CIAV only, RB1B + CIAV, 584A + CIAV, or nothing. Samples of spleen, thymus, and bursa of Fabricius were collected at 4, 7, 10 and 13 days post inoculation (DPI). Thymic and bursal atrophy at 13 DPI and final mortality at 30 DPI were significantly greater in birds inoculated with 584A with or without added CIAV, or with RB1B plus CIAV, compared to birds inoculated with RB1B alone. Both amounts of virus reisolated and levels of virus detected by QC-PCR were greater at 4 DPI in 584A inoculates compared to RB1B inoculates. These results indicated that inoculation of chickens with the 584A isolate caused a more robust early cytolytic infection compared to inoculation with RB1B alone and support the classification of 584A as a vv+MDV strain. Coinfection with CIAV exacerbated vvMDV strain RB1B infection. The extent of this exacerbation was less evident when birds were co-infected with 584A and CIAV.