犬アカルス疹に関する研究

Abstract

Experiments were carried out to clarify the state of infection among bitches and their litters. Mites after their exposure to natural surroundings were tested for biological characters and infectivity. In addition, investigation was made to determine whether indirect contagion occurred or not.1) Of 7 dams of the affected dogs examined, 6 were found infested with mites, though they were apparently healtht. Of 59 puppies given birth from them, 38 were positive and 10, born from uninfected dams, were negative, and the other 11 could not be examined. In 30 young born from 5 affected dams, mites were found without exception. In 9 cured dams with no clinical signs left, mites were found in follicles of the skin for about two years. So it is considered that the highest opportunity of infection might be in the suckling period when there are close relatoins between dam and puppy. Bitches showing no signs of disease might be the most significant as carriers.2) Mites separated trom hair follicles showed a movement continually till death under the themopactic zone. Inductivity of mite movement by carbon dioxide was not remarkable, as Ixodes mites were found lying in wait for new hosts. Mites which had fallen on the floor of the kennel suffered the influence of such environmental factors as drought and putrefaction of media and died in a few days. Though mites themselves were able to survive at low temperature and high humidity for a long time, they had no ability of infection under such conditions. For these reason, it was concluded that indirect contagion of mites scarcely occurred.