| As important vectors of zoonoses, fleas can transmit plague bacillus, Rickettsia, Bartonella, tapeworm and other pathogens. They are not only caused many diseases, such as plague, cat-scratch disease, rickettsioses and taeniasis, but also lead severe harassment to human and animals by stinging and blood sucking. Because of the only way to get nutrition and water, adult fleas have to catch the hosts and hematophagia successfully. These are critical for their survival, mating, reproduction and even the life span. In this research, behaviors of host odor selection in Ctenocephalides felis felis, Xenopsylla cheopis and Leptopsylla segnis and their optical histology to provide evidence for the relationship study of "flea-host/human-diseases". Based on the Y-tube olfactometer, which used to research the odor selection of insects, a method for flea behavior of host odor selecting was established. Using this method, the host selection of Ctenocephalides felis felis, Xenopsylla cheopis and Leptopsylla segnis were carried out in the white rat, white mouse, cat and dog. At the same time, fleas'histological changes before and after blood meal were studied by conventional histological techniques and HE staining. The followings are some of the results:1. Through the method establishing, it had obtained the optimum test conditions, made the indexes clearing, analyzed the host odor selection characteristics of different fleas to the tested host, and proposed some related notes.2. By this flea Y-tube olfactometer method, we studied host odor selection behavior in three host specificity strains of Ctenocephalides felis felis. The results showed that:①The main host of C. felis felis was cat. Naturally, the selection of this flea to dog is stronger than that of rats and mice.②After raised by rats and mice, Ctenocephalides felis felis adapted to them.3. Using this method, we also studied odor selection of X. cheopis and Leptopsylla segnis (both are lab strains) to different host animals. The results are as follows:The odor selection of X. cheopis to rats and mice are stronger than that to cats and dogs. The order about odor selection of L. segnis to the four animals is rat, mouse, cat, dog. It shows that dominating host of L. segnis is Rattus norvegicus, followed by Mus musculus.4. By the conventional histological techniques and HE staining, we could get the results:①Using the fleas slices, the optical histology of C felis felis, X. cheopis and L segnis could be read to distinguish their organs and tissues.②Some changes could be found in fat body, reproductive system and digestive system by observing the slices of fleas.③The midgut epithelial cells of the new eclosion adult of L. segnis were smaller than that of C. felis felis and X. cheopis, and there was no significant difference between that of C felis felis and X. cheopis. After feeding, the midgut epithelial cells of C. felis felis were thicker than that of X. cheopis and L. segnis, and there is no significant difference between X. cheopis and L. segnis.④Compared with that of starvation, the diameter ratio of midgut and proventriculus of fleas was 1.5-2 times approximately after feeding.⑤After 24h blood feeding, the lumen of female L. segnis became increased, and the yolk granules of ovarioles began to precipitated, and the fat body stained purple. At the same time, the sperm bundles became flat and straight in male ones, but their fat body had no changes. After 48h feeding, the oocytes of female fleas became ruptured. And the nucleus of the midgut epithelial cells had arranged obviously near the intestinal lumen. |
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