SYNERGISM BETWEEN CHICKEN ANEMIA VIRUS (CAV) AND AVIAN REOVIRUS FOLLOWING DUAL INFECTION OF 1-DAY-OLD CHICKS BY A NATURAL ROUTE

One-day-old specific-pathogen-free white leghorn chicks were dually in fected with the Cux-1 isolate of chicken anemia virus (CAV) and separa te avian reovirus strains (S1133 or Uchida) by an oral route. Fourteen days after inoculation, chicks were bled, and packed cell volumes (PC Vs) were determined. Chicks were also weighed and examined for macrosc opic changes to the bone marrow, thymus, and bursa of Fabricius. The r esults obtained following dual inoculation of chicks with CAV and reov irus were compared with results obtained from mock-infected chicks or chicks inoculated with CAV or reovirus alone. Chicks dually infected w ith CAV and the S1133 reovirus strain had significantly (P < 0.05) low er weight gain and more severe tissue damage than chicks inoculated wi th either virus alone. In addition, a significant (P < 0.05) reduction in the mean PCV was seen in these dually infected chicks when compare d with chicks inoculated with CAV alone. No increase in the severity o f the disease signs was observed following dual infection with CAV and reovirus strain Uchida.