>Nancy - When I had my little EFB outbreak last spring it was borne in on me the fundamental difference between the two brood diseases: EFB is a disease of the larval stage and AFB is a disease of the pupal stage. Before that, this point was somehow unclear to me.  It was a useful thing to learn, however, as it sharpened my observational and diagnostic skills. 


>The infection in individual larvae is not always lethal. The larvae may die before capping and be ejected from the colony, die
after capping and void their infective intestinal contents within the brood-comb cell or succeed to pupate and form normal or
undersized adults (Bailey, 1959b). Even larvae experimentally fed high doses of M. plutonius in bioassays survived the infection to
reach pupation, although pupation was delayed.

As Treavor mentioned, there are other secondary infections that can invade EFB stricken larvae.  As a result, the odor from decay can vary. In the case of P. alvei, it was once considered the main cause of both EFB and AFB when they were considered one disease - foulbrood.  We are warned that the combination of M. plutonius and P. alvei can make for a confusing field diagnosis if you're poking around in cells thinking it may be AFB because, as mentioned, a dead capped pre-pupa will rope out to some extent. Anyway, I would miss the dead pupa because I stop looking after seeing the larval symptoms.  


>Paenibacillus alvei is a saprophytic, aerobic bacterium which cannot grow in the gut of a normal larva, but becomes established
in chronically diseased colonies growing in larval remains (Bailey, 1963). Because it is a spore producing bacterium, it survives,
germinates and multiplies more readily in dead bees than other saprophytes. 

>European foulbrood in honey bees
E Forsgren - Journal of invertebrate pathology, 2010 - Elsevier

>https://pdfs.semanticscholar.org/edaf/c693e1549f22c69e59c7ae6568796546fcfd.pdf



Bill Hesbach
Northeast USA

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