Experimental Studies on Pathogenicities and Developmental Stages of Nosema apis(Zander, 1909)

Kang, Yung Bai; Kim, Dong Sung; Jang, Du Hwan

Korean Journal of Veterinary Research 1976;16(1):11-25.

Yung Bai Kang¹, Dong Sung Kim¹, Du Hwan Jang²

¹Institute of Veterinary Research, Office of Rural Development
²College of Veterinary Medicine, Seoul National University

꿀벌에 기생(寄生)하는 Nosema apis의 병원성(病原性)과 발육단계(發育段階)에 관한 연구(硏究)

강영배¹, 김동성¹, 장두환²

¹농촌진흥청 가축위생연구소
²서울대학교 수의과대학

Abstract

Studies on pathogenicities and developmental stages of Nosema apis (Zander, 1909) were carried out through artificial infection to Nosema free honey bees with various levels of spores isolated from local honey bee colony. The results obtained were summarized as follows: 1. The clinical symptoms were observed as dysentery, enteritis of mid-gut (enlargement and decoloration), crawling posture and shortening of the longevity of worker bees in the rearing honey bee colony inoculated with the spores. 2. Number of spores harvested from laboratory rearing honey bees were progresively increased to 4 weeks after inoculation. The regression equations and coefficients of correlations to various spore levels were as follows in each treatment colony. Colony 1. ($$1,000{ imes}10^4spores/ml$$) $$y_{c1}=471{ imes}10^{4}x+454{ imes}10^4(r=0.65^*$$) Colony 2. ($$500{ imes}10^4spores/ml$$) $$y_{c2}=340{ imes}10^{4}x+207.8{ imes}10^4(r=0.99^{**}$$) Colony 3. ($$100{ imes}10^4spores/ml$$) $$y_{c3}=150{ imes}10^{4}x+84.2{ imes}10^4(r=0.99^{**}$$) Colony 4. ($$10{ imes}10^4spores/ml$$) $$y_{c4}=13.8{ imes}10^{4}x+13{ imes}10^4(r=0.98^{**}$$) 3. Average longevity of worker bees artificially infected with Nosema apis was shortened as 21.7~43.8% compare to the control. (p<.05, p<.01) 4. The spores which were isolated from honey bee colony infected with Nosema disease were ovoid or spherical form, and measured, as a rule, from $4.7{mu}m$ to $6.1{mu}m$ (mean $5.3{mu}m$) in length and from $2.4{mu}m$ to $3.2{mu}m$ (mean $2.9{mu}m$) in width. 5. In the mid-gut of honey bees, the spore was progresively germinated and became trophozoite stage. The trophozoites were grown to meronts and their binary fission were begun. The divided two sporoblasts were developed to the spores which had elastic membrane. The new spores were shed in excreta of honey bees 10~15 day after inoculation at $25{pm}2$ centigrade. 6. The ultrastructure of spore membrane consisted of three layers, such as, outer, middle and inner layer. The sporoplasm consisting lamellar structure occupied only anterior part of the spore and was often extended to posterior direction where definite vacuoles and a polar filament was able to detect.