Immunization of Ducks against Malaria by Means of Killed Parasites with or without Adjuvants

Abstract

Attempts to produce immunity against malaria in birds by the injection of killed malaria parasites have almost always failed. Gingrich (1) and Jacobs (2) however obtained results suggesting that protection against malarial infection in birds can be produced. Gingrich using P. cathemerium in canaries injected excessive numbers of heat or formalin killed parasites intravenously and challenged the birds two days after vaccination. Although evidence of protection was obtained, such a procedure could have little or no practical application. Jacobs employing P. lophurae in white Pekin ducks combined killed parasites with staphylococcus toxoid and used this preparation as a vaccine. Four of six ducks injected with this vaccine appeared to be protected as compared with non-vaccinated control ducks. Two ducks showed little if any protection, one died with high parasitemia whereas the other survived after high parasitemia. The birds were challenged in this experiment on the third day after the last of five injections of vaccine.