DR. H. B. FANTHAM AND MISS A. PORTER ON BEE-DISEASE. 625 



A Bee-disease due to a Protozoal Parasite (Nosema apis). 



Dr. H. B, Fantham, F.Z.S., and Miss Annie Porter, D.Sc, 

 exhibited some diseased bees and combs infected with a minute 

 pathogenic protozoal parasite, apparently the same as Nosema 

 apis found by Zander in diseased bees in Bavaria. Microscopic 

 px'eparations and drawings of the parasite, Nosema ajjis, were also 

 shown, as well as healthy bees and combs in contrast. The 

 material exhibited was obtained from Cambridgeshire and 

 Hertfordshire in March, 1911. Some of the infected combs 

 were brown in colour instead of the normal yellow (combs of the 

 same age being compared), while the infected bees suffered from 

 a sort of dry dysentery which rapidly pioved fatal. 



The pathogenic agent of this dry dysentery, Nosema apis, 

 formed thousands of minute spores which fouled the hive, while 

 infection was probably spread to new hives by hungry, weakly 

 bees attempting to enter healthy hives. The spores, about 2 to 

 3 /J. by 4 to 6/u, were the resistant and cross-infective stages of the 

 Protozobn. The pai-asite Nosema ajois was closely allied to that 

 of pebrine, the silkworm disease due to Noseina homhycis. 



The trophozoite and pansporoblast stages of the Nosema apis 

 had been observed in the gut-epithelium of the bee. Some spores 

 with polar filaments extruded had also been found. It was very 

 probable that the young, growing and multiplicative stages of the 

 parasite were capable of killing the bees before the formation of 

 spores had been attained, for dead bees were often found in which 

 only young stages of the pai-asite could be detected, occurring 

 especially in the chyle-stomach and intestine. Like N'. homhycis, 

 the bee-parasite was possibly capable of hei-editary infection, as 

 infected bee-lai'VJe and a dead infected queen had been found 

 and examined. Maassen had recently found infected drones in 

 Germany, but the infection in drones was stated to be limited to 

 the intestine. 



That Nosema apis was fatal to bees and allied Hymenoptei'a 

 had been shown by the exhibitors by feeding healthy hive-bees, 

 mason-bees, and wasps with honey infected with Nosema spores ; 

 also by placing hive-bees dead of the disease among healthy hive- 

 and mason-bees and wasps, and by direct contamination of healthy 

 bees with infected fsecal matter. In each case the insects ex- 

 perimented upon succumbed to the efiects of Nosema apis. 

 In iSTature the method of infection is probably contaminative, 

 healthy bees becoming infected by swallowing the spores of the 

 parasite. 



It shovild be noted that the virulence of the parasite appeai-ed 

 to vary in bees at difierent times of the year and in different 

 localities. Bad seasons are usually followed by increase of disease. 

 Some bees became chronics, forming reservoirs of spores and so 

 acting as parasite-carriers. 



The only certain destructive agent of the Microsporldian 

 spores was fire, and all infected bees and hives, and any debris 

 therefrom should be most carefully burned. 



