The 1944 epizootic of horsesickness in the Middle East

Abstract

(1) The history of horsesickness in Egypt and Palestine is traced. (2) It is believed that the 1944 epizootic was started in Egypt by the introduction of one or more infected equines into the Komombo area from the South and that it was not a recrudescence of the infection introduced the previous year. (3) The chief characteristics of the epizootic are described and figures are quoted to show the morbidity and mortality in horses, mules, and donkeys. (4) The manner in which infection was introduced in to Palestine remains obscure, and the various factors involved are discussed. The possibility that infected insect vectors were carried by aircraft, not only from Egypt, but from some other focus is discussed. (5) The great similarity but not complete identity between the Egyptian and Palestine strains of virus, as determined by in vitro and in vivo laboratory experiments, is reported. The chief point of resemblance is the similarity of antigenic structure; the chief points of difference are the period of incubation in horses and the virulence. (6) Attention is directed to the susceptibility of the donkey. (7) The general measures of control and their relative effectiveness are described. (8) Mass immunization is shown to be the only effective measure of control, and figures are given to indicate the rate of development of immunity. (9) The future of horsesickness in the Middle East and the measures necessary to prevent reinfection are discussed.