DIAGNOSIS OF BEE DISEASES. 13 



NOSEMA DISEASE. 



Nosema disease is an infectious disease of adult bees. It is the only 

 adult disease which at the present time can be diagnosed by labora- 

 tory methods (White, 1918). Sixty years ago Donhoff (1857) ob- 

 served an infectious condition among adult bees in which, upon 

 examining the stomach of affected bees, small oval bodies were 

 found. This work had been practically forgotten until Zander 

 (1909) reported some interesting findings in a disorder of adult 

 bees. He found that the stomach wall of bees taken from colonies 

 suffering from what he called "malignant dysentery" contained a. 

 protozoan parasite. To this parasite he gave the name Nosema apis. 



In England (Graham-Smith, Fantham, Porter, Bullamore, and 

 Maiden, 1912) Nosema infection in bees has been associated with a 

 disorder referred to as the Isle of Wight bee disease. Recent in- 

 vestigations in Scotland (Anderson and Rennie, 1916) have lead to 

 a somewhat different view. As Nosema apis occurs in the group 

 Microsporidia the name " microsporidiosis " has been given to the 

 disease (Fantham and Porter, 1912). 



Nosema disease is widely distributed. It occurs in Germany, 

 Australia, Switzerland, and England at least. The junior author 

 ( 'White, 1914) has found the parasite Nosema apis in samples of bees 

 from a large number of the States of the United States and from 

 Canada. The disease weakens and even kills colonies and is there- 

 fore one of interest to beekeepers. The exact losses from it are not 

 known, but in America they are less than has been attributed to it in 

 some other countries. 



OBTAINING THE BEES. 



Either dead or living bees are suitable for examination. Dead 

 bees may be dry and still be suitable material. Living bees for 

 examination can be sent very satisfactorily in mailing cages such 

 as are used by queen breeders; dead ones may be sent in any con- 

 venient way. A complete history of the colony and apiary as to 

 disease should accompany the bees. 



GKOSS CHARACTERS. 



The presence of various symptoms has been mentioned as being 

 of importance in the diagnosis of Nosema infection. Among these 

 are noted the spotting of the hive with feces, abdominal distention, 

 the presence of shiny bees devoid of hair, and the activity of the 

 bees, either in the cages or when free. These are of questionable 

 value. It is upon the presence or absence of Nosema spores that the 

 diagnosis is based. Bees otherwise apparently healthy may, upon 

 examination of the stomach, show the presence of spores of Nosema 

 apis in large numbers. 



