ZANDER, AUGUST, 1909. 89 



2. The evidence obtained indicates that tJie disease is infectious. 



3. An organism was oncountorod in a numbor of diseased bees, to 

 which ^laklen gave the name Bacillus pestiformis apis. 



4. Tliis organism was not proven by Maiden to bo the cause of 

 the disease. 



Zander, August, 1909. 



In 1909, Dr. Zander, at Erlangen, Germany, wrote an interesting 

 paper * concerning the cause of a disease affecting the adult honey 

 bee 



From his studies Zander was led to believe that there are two 

 forms of dysenteiy. One form he considers to be nonmfectious and 

 comparatively harmless. The cause of this form is attributed to 

 various conditions, such as disturbance of the colony, queenlessness, 

 improper winter stores, deficient opportunity for a cleansing flight, 

 etc. A second form of dysenteiy Zander refers to as the malignant 

 form. In referring to the virulence of this form Zander says that it 

 has all the characteristics of an infectious disease, destroying more 

 colonies in one spring in the neighborhood of Erlangen than foul 

 brood had during the entire preceding year in the whole State of 

 Bavaria. 



During his mvestigations in 1907 Zander found in the mid-gut of 

 diseased bees a protozoan to which the name Nosema apis was given. 

 This portion of the intestine of all the bees which died of the "viru- 

 lent" form of dysenteiy was found to be milk-white and completely 

 filled with Nosema spores. Queens from dysenteric colonies were 

 examined and found also to be infected with the protozoan. No 

 drones were found infected. This was supposed to be due to the fact 

 that there are no drones during the active dysenteric season. The 

 excrement from the bees also contained numerous spores. 



Zander expresses the behef that the transmission of the disease is 

 made possible by the deposit of excrement on the frames and walls of 

 the liive, wdiich takes place when no opportunity is afforded the bees 

 for a cleansing flight. The mutual feeding practiced by bees hastens, 

 it is suggested, the spread of the infection. The bees are supposed 

 to be subjected to further infection from without on account of the 

 spores that are spread about through the mecUum of the excreta of the 

 flying bees. Robbing also is given as a fruitful means of transmission. 

 The use of contaimnated combs from apiaries in wliich the infection 

 is present is also thought to be a means for the spread of the disease. 



The prognosis is supposed to depend somewhat upon conditions. 

 Long, hard winters are given as a cause of veiy heavy losses with this 

 disease. If, on the other hand, the spring is warm with a good flow 



I Zander, Dr. Enoch, August, 1909. Tierische Parasiten als Krankheitserreger bei der Biene. Miinche- 

 ner Bieneuzeitung, Heft 9. Pp. 11. 



