Development of brood infected with American foulbrood

Infected development

The developmental stages of worker brood infected with AFB are outlined in Fig. 7 below.

Larvae are most susceptible to AFB infection when they are less than 24 hours old. Millions of spores are required to infect a larva more than two days old, but larvae up to 24 hours old can become infected with ten spores or fewer.

Figure 7: The developmental stages of worker brood infected with AFB

Compare picture above to normal development

Although the AFB vegetative rods multiply in the gut of the larva, they do not penetrate the gut wall and multiply in its tissues until it stretches out before pupation (prepupal stage). Visual disease symptoms do not become apparent until death occurs, either just before or just after the larva pupates.

Infected larvae do not usually exhibit disease symptoms until after the cells have been capped. Where uncapped diseased larvae and pupae are found it is usually because the cappings have been removed by house bees.

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AFB Quiz
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How well do you know what you need to know about AFB and beekeeping? Take our short quiz and find out.

AFB Videos

Our videos cover everything from your legal obligations to how to recognise AFB, collecting cell and bee samples and more.

AFB Symptoms

There’s a lot of good information here, telling you everything you need to know about recognising AFB: the visual symptoms, smell of AFB and more.

AFB Inspection and Diagnosis
Inspection and Diagnosis

Successfully eliminate AFB by telling the difference between symptoms of AFB and other brood diseases in the hive. We tell you the best methods for inspecting your hives.

The Law

New Zealand beekeepers have a number of legal obligations that must be met regarding AFB disease. Read the shortened list in summary, here.

AFB Elimination

Most hives become infected because bees, honey or equipment have been put into a hive from another hive that is infected with AFB. Lower your chances of an  AFB infection by reading this section.

AFB Course Info
AFB Recognition Course Info

Find out when the next AFB Recognition and Competency Courses, or Refresher Courses are available. These are held throughout the year in various New Zealand locations across the South Island and North Island.

The AFB App

Follow the link below to open the App. Once open to save to your device you need to bookmark the URL on your phone so you can find it easily again. Please click here to open.