Walter T. Johnson (1892 to 1937): pioneer of coccidiosis research in the fowl.

Abstract

Walter T. Johnson (1892 to 1937), veterinarian at Western Washington Agricultural Experiment Station (WWAES), Puyallup, Washington, USA, and subsequently poultry pathologist and professor of veterinary medicine at Oregon State University Agricultural Experiment Station (OSAES), Corvallis, Oregon, USA, made many important contributions to our understanding of the disease coccidiosis. His pioneering work included the first description of Eimeria necatrix and Eimeria praecox from the chicken and identification of four other species of Eimeria from the fowl. He demonstrated the relationship between numbers of oocysts ingested and severity of infection, and described the phenomenon of host specificity and the significance of immunity. Contrary to widespread opinion, he considered that coccidia were not involved in blackhead disease and other pathological conditions reported from the fowl. His views on control were ahead of his time and he anticipated the possibility of vaccinating birds by infecting them with live oocysts. In addition to his studies of coccidiosis, Johnson introduced a vaccine for fowlpox and ran a pullorum-testing laboratory. He produced numerous articles of an advisory nature on a diverse range of topics concerned with poultry and cattle. Much of Johnson's research was published in bulletins of the WWAES and OSAES that are not widely available and consequently have often been overlooked by the scientific community. Following his premature death, the director of OSAES claimed, "more information on the parasitic disease coccidiosis has been discovered at the Oregon Station than at almost any other place. The Oregon Station is probably the only institution in the world where six known species of coccidia of the chicken are available in pure culture" (Anonymous, 1938a). This is a claim that few institutions can match today.