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 infected with the Cux-1 isolate of chicken anemia virus (CAV) and separate avian reovirus strains (S1133 or Uchida) by an oral route. Fourteen days after inoculation, chicks were bled, and packed cell volumes (PCVs) were determined. Chicks were also weighted and examined for macroscopic changes to the bone marrow, thymus, and bursa of Fabricius. The results obtained following dual inoculation of chicks with CAV and reovirus were compared with results obtained from mock-infected chicks or chicks inoculated with CAV or reovirus alone. Chicks dually infected with CAV and the S1133 reovirus strain had significantly (P < 0.05) lower weight gain and more severe tissue damage than chicks inoculated with either virus alone. In addition, a significant (P < 0.05) reduction in the mean PCV was seen in these dually infected chicks when compared with chicks inoculated with CAV alone. No increase in the severity of the disease signs was observed following dual infection with CAV and reovirus strain Uchida.