T H E BEHAVIOR OF POX VIRUSES I N T H E RESPIRATORY TRACT IV. THE NASAL INSTILLATION OF FOWL POX VIltUs IN CHICKENS AND IN MICE

The work which is here reported was undertaken in part as an extension of our previous observations on the behavior of pox viruses in the respiratory tract (1, 2) and in part to determine whether or not fowl pox virus was capable of simulating the clinical syndrome of chickens referred to as roup. Roup, which is also known by a variety of names as infectious catarrh, infectious rhinitis, and fowl coryza, is defined as a communicable disease of natural occurrence in chickens characterized by nasal and ocular inflammation which may or may not be accompanied by an outward discharge. Even before the etiology of roup was established a number of investigators, Haring and Kofoid (3), Beach (4), Doyle and Minett (5), were agreed that it was a distinct entity and unrelated to fowl pox. Their evidence was incomplete but was nevertheless significant since reciprocal protection was not demonstrable. We began an investigation of the syndrome in 1932 shortly after De Blieck (6) had shown that the influenza-like bacterium now known as Hemophilus gallinarum was of etiological significance. His work and ours (7-9), which led to the recognition of three clinical types of the disease, were likewise in agreement with these conclusions and afforded ample evidence that roup may. occur naturally and be reproduced experimentally in the absence of fowl pox. Much of the earlier work was concerned with the skin inoculation of normal birds with nasal exudates from naturally infected chickens, fowl pox virus not infrequently being demonstrable. The actual nasal instillation of virus suspensions or of exudates was only occasionally undertaken, with scant reference to the results even though an ocular-nasal form of fowl pox was recognized. Our observations as outlined in this paper are largely concerned with this route of introduction, nasal injections of fowl pox virus being made in the absence of the causative agents of roup.