Genetic control of cellular infection by subgroups A and C RNA tumour viruses in guinea fowl.

An investigation was carried out in guinea fowl to determine their susceptibility to infection by Rous sarcoma viruses of subgroups A and C. A standard dose of each subgroup virus was inoculated into 14-day-old embryos via the chorioallantoic membrane (CAM). On the 10th day after inoculation, 50% of the embryonic chorioallantoic membranes were harvested to assess their infection status (CAM(+) or (-)), while the rest were allowed to hatch. The hatchabilities of the embryos inoculated with subgroups A and C were about 50% and 57%, respectively. The relative sensitivities of guinea fowl to infection by viruses of subgroups A and C were observed to be 0.220 and 0.003, respectively, as compared to chickens (1.00). Mortality due to subgroup A virus-induced liver tumours (LT) was 54% and four phenotypic subclasses, namely CAM(+) LT(+), CAM(+) LT(-), CAM(-) LT(+) and CAM(-) LT(-), were observed in guinea fowl as in chickens. However, a higher incidence (31%) of conversely associated phenotypes, i.e. CAM(+) LT(-) and CAM(-) LT(+), were observed in guinea fowl. Mortality caused by subgroup A virus-induced liver tumours was first observed in inoculated guinea fowl keets during the 3rd week after hatching, and 93% of the mortality occurred within 6 weeks. The peak mortality occurred in the 4th week after hatching. The target organs for transformation were considered to be the liver and spleen because of the equal incidence of tumours in these organs. Males and females were equally likely to die from liver tumours.(ABSTRACT TRUNCATED AT 250 WORDS)