EFFECTS OF MILBEMYCIN-D ON MICROFILARIAL NUMBER AND REPRODUCTION OF DIROFILARIA-IMMITIS IN DOGS

被引:6
作者
SASAKI, Y
KITAGAWA, H
机构
[1] Laboratory of Internal Medicine, Division of Veterinary Medicine, Faculty of Agriculture, Gifu University, Gifu 501-11
关键词
CANINE; HEARTWORM; MICROFILARIA; MILBEMYCIN-D; OCCULT INFECTION;
D O I
10.1292/jvms.55.763
中图分类号
S85 [动物医学(兽医学)];
学科分类号
0906 ;
摘要
A single dose (1 mg/kg) of milbemycin D was administered orally to 24 dogs with microfilaremia of Dirofilaria immitis, and the number of circulating microfilariae was counted weekly. The number was decreased by 3 to 8% of the pretreatment levels 1 week after the drug administration. The number remained relatively stable for the first 8 weeks and was gradually increased thereafter without returning to the pretreatment levels by 20 weeks. Three or 4 dogs each were euthanatized on day 1, and 1, 4, 8, 12, 16 and 20 weeks after the drug administration to examine the effects of the drug on intrauterine microfilariae and embryos of the worms. Although no intrauterine microfilariae were destroyed directly by the drug, degeneration and collapse of morular embryos and decrease in the number of intrauterine microfilariae were observed 12 after weeks the drug administration. These findings became more remarkable with time, and no intrauterine microfilariae developed in any worms by 20 weeks. The electron-microscopic findings revealed that the nucleoli of ocytes had a high density in the worms of 1, 4 and 8 week groups. Unequal size of cleavage cells and decrease of polysome number were noticed in the early-stage embryos after 8 weeks. It was assumed that the drug might have some effect on the chromosomes or genes in the germinal stem-cell of the heartworm and interfere with protein syntheses, resulting in inhibition of embryonic development. Twelve dogs were given milbemycin D (1 mg/kg) a total of 4 or 6 times monthly according to a prophylactic program. Circulating microfilariae disappeared after 1 to 5 treatments, and none of them were confirmed at the beginning of the next mosquito season. Milbemycin D was considered to inhibit the development of heartworm embryos and to induce occult heartworm infection.
引用
收藏
页码:763 / 769
页数:7
相关论文
共 17 条
[1]  
ANANTAPHRUTI M, 1982, Japanese Journal of Parasitology, V31, P517
[2]  
ASHBURN LL, 1945, ARCH PATHOL, V40, P334
[3]  
BLAIR LS, 1979, AM J VET RES, V40, P1031
[4]  
Boisvenue R. J., 1975, , Proceedings of the Heartworm Symposium 1974, 16-17 March, 1974, Auburn, Alabama, USA. (Compiled: Amer. Heartworm Soc.)., P93
[5]  
Jackson R. F., 1981, Proceedings of the Heartworm Symposium '80, Dallas, Texas, 23-24 February 1980., P131
[6]  
KOSHIHARA H, 1974, SAIBOUGAKU TAIKEI, P1
[7]   ABNORMAL PATTERNS OF EMBRYOGENESIS IN DIROFILARIA-IMMITIS TREATED WITH IVERMECTIN [J].
LOK, JB ;
HARPAZ, T ;
KNIGHT, DH .
JOURNAL OF HELMINTHOLOGY, 1988, 62 (03) :175-180
[8]  
OHOISHI I, 1986, INUSHIJOUCHU
[9]  
PLUE RE, 1985, P HEARTWORM S 83, P153
[10]  
SAKAMOTO T, 1984, Journal of the Faculty of Agriculture Iwate University, V17, P69