Studies in the epidemiology of infectious myxomatosis of rabbits. IV. Observations of disease behaviour in two localities near the northern limit of rabbit infestation in Australia, May 1952 to April 1953.

Abstract

SummaryField observations supplemented by laboratory tests were carried out on the occurrence of myxomatosis at two sites with contrasting environments near the northern limit of rabbit infestation in Australia, during the period May 1952 to April 1953.In spite of the very low incidence of cases of myxomatosis observed in wild rabbits during that period great reductions in the rabbit population occurred.Analysis of the results of serum surveys indicates that myxomatosis was present and caused minor unobserved epizootics during this period, The overlap in this area of rabbit breeding and active transmission of myxomatosis probably led to a high death rate in the sub-adult rabbit population.In spite of continued reintroduction of fully virulent standard virus into the areas, all strains of virus recovered were somewhat attenuated. There was a suggestion that at Texas the degree of attenuation increased during the study period.Sex ratios and data on reproduction are presented for the 1488 rabbits shot at the two areas. Recovery from myxomatosis appeared to have no adverse effect on the fecundity of the female rabbit.