Major brood and adult diseases of Honey bee Apis mellifera

1. DISEASES HONEY BEE (APIS MELLIFERA):
IDENTIFICATION AND MANAGEMENT
DR. MANDEEP RATHEE
Training Assistant, KVK, Kaithal
CCS HAU, Hisar

2. I. BEE BROOD DISEASES
 Bacterial diseases
American foul brood (AFB), Paenibacillus larvae (White) Ash et al.
European foul brood (EFB), Melissococcus plutonius (White) Bailey and Collins
 Fungal diseases
Chalk brood, Ascosphaera apis (Maasen ex Claussen) L. S. Olive & Spiltoir
Stone brood, Aspergillus spp.
 Viral Diseases
 Sac brood (Sac Brood Virus)
 Thai sac brood (Thai Sac Brood Virus)
MAJOR DISEASES OF HONEY BEE

3. American foul brood (AFB)
• Causal organism: Spore forming bacteria, Paenibacillus larvae
• Young honey bee larvae become infected when they consume P. larvae
spores in their food.
• The spores germinate in the gut; bacteria then move into the tissues,
where they multiply enormously
• Infected larvae normally die after their cell is sealed.
• Adult honeybee workers are not affected by AFB spores but spread the
spores to larvae while feeding them contaminated food.
• Most dreaded and highly infectious bacterial disease (not reported in
India)

4. Symptoms: AFB
• The diseased larva changes from a normal pearly white colour to a
creamy brown and then darkens
• When a matchstick is thrust into the cell of the decomposed pupa, it
draws out a ropy thread of several centimeters in length
• Dead larvae turns to dark brown or black scales stuck tightly to lower
side of cell
• Unpleasant smell from decomposed larvae
• Brood cell cap perforated
• Patchy brood

5. AFB

6. AFB
The presence of tongues of dead pupae is a
very reliable AFB field sign

7. European foul brood (EFB)
• Causal organism: Non spore forming bacteria,
Melissococcus plutonius
• 2-day-old young honey bee larvae become infected when
they consume P. larvae spores in their food.
• The bacteria invade the midgut of 4–5-day-old larvae and
multiply there, competing with the larva for its food.
• The larvae that die from the disease do so because they have
been starved of food.
• Larvae twisted with visible tracheal tubes
• It is a disease of unsealed (open) brood
• It is less serious than AFB (reported in India)

8. Symptoms: EFB
• Dead larvae become soft, watery and dull yellow
• The infected larvae lay upright attached with sidewalls of the cells
• Dead larvae turns to dark brown or black scales stuck tightly to lower
side of cell
• Dead larvae finally dry and become brown removable rubbery scales at
the bottom of the cell.
• Dead larvae appear before pupation
• Vinegar like foul smell
• Patchy brood

9. EFB
Patchy brood
EFB
Healthy versus infected larvae

10. EFB
A) Apis mellifera Infected larva (brown) with visible tracheal system
B) Apparently healthy larvae (pearly white, glistening, C-shaped)
C) Curled, discolored larvae, twisting up in the cell

11. EFB
Twisted dead larva

12. Management
• Keep colonies strong and unite weak colonies
• Isolate infected colonies, control robbing and drifting of bees
• Do not exchange infected frames from infected colonies to healthy ones
• Maintain prolific queens
• Destroy weak colonies and colonies with a high proportion of diseased
brood
• Treat diseased colony with 0.5–1.0 g oxytetracycline (terramycin) in
500 ml concentrated sugar syrup /colony
• Sterilize the combs and other hive parts with formalin at 150 ml/l water,
for 48 h at 43°C
• Breeding disease-resistant strains of bees
• Only cure for AFB is to burn bees in hive in its entirety and bury

13. Chalk brood
• Causal organism: spore-forming fungus Ascosphaera apis
• The threadlike, vegetative growths (‘hyphae’) of the fungus invade the
body tissues of infected larvae
• Larvae dies of starvation
• Fungal growth turns larval body into white chalk
• Larvae killed after they have been capped
• Three–four-day-old larvae and those on periphery of brood area are
more susceptible
• Workers, drones and queens are all susceptible to the disease

14. Symptoms: Chalk brood
• Prevalent in cool weather
• Diseased larvae are stretched out in their cells in an upright position
• Larvae infected with Chalkbrood disease usually die after capping
• Dead larvae are chalk white
• Chalkbrood mummies, once dry, are loose in the cell and can be
removed easily
• Hygienic workers expel these mummies out of hive, hence mummies
are visible at the entrance to the hive

15. Chalk brood

16. Stone brood (Aspergillosis)
• Causal organism: Aspergillus spp.
• The main species of fungi responsible for the disease in honeybees are
Aspergillus flavus and, less frequently, Aspergillus fumigatus and
Aspergillus niger
• Aspergillus infects the bee through the cuticle as well as through the gut
if the spores are ingested
• Aflatoxins are the major reason of death in stone brood-infected
honeybees
• Mummification of the brood of a honeybee colony

17. Symptoms: Stone brood
• Irregular brood pattern
• Fungal infection give rise to a characteristic ring near the head of the
infected larvae
• Larvae die in capped cells and dead larvae difficult to remove
• Green mummified larvae can be observed in the brood combs, and on
the bottom board or the landing board of the hive.
• The mummified larvae resemble little white, yellow or green stones and
are hard to crush
• Rare cases may transmit to adult bees: symptoms like agitation,
paralysis or weakness and inability to fly away from the hive, swollen
abdomens or morphological changes, crawling bees outside the hive
• Younger bees die earlier

18. Stone brood

19. Management
• Keep colonies strong and unite weak colonies
• Isolate infected colonies, control robbing and drifting of bees
• Do not exchange infected frames from infected colonies to healthy ones
• Re-queening with a queen from a chalk/stone brood-free colony
• Destroy weak colonies and colonies with a high proportion of diseased
brood
• Do not feed the bees mouldy pollen, and do not breed bees on mouldy
combs
• Breeding disease-resistant strains of bees
• Maintain proper ventilation
• Ensure a right balance between adult bees and brood
• Spray 0.7 per cent thymol

20. Sac brood and Thai sac brood
• Causal organism: SBV and TSBV
• Thai sac brood virus (TSBV): Apis cerana colonies
• Sac brood virus (SBV): Apis mellifera colonies
• SBV that attacks A. mellifera is less virulent than TSBV
• Peculiar characteristics:
•Larvae fail to pupate
•The presence of prepupae with raised, pointed heads in the comb cells
• In 1991-92, there was an outbreak of the virus in India which resulted
in the destruction of more than 90 per cent of the Apis cerana colonies
in south India
• TSBV again vanished Apis cerana colonies in 2021 in Karnataka

21. Symptoms: Sac brood
• Larvae infected with sac brood virus show disease symptoms after the cell has
been capped
• The larvae lie stretched out on the lower walls of their cells
• Clear granular fluid accumulates between the skin and the body of the larva,
causing a sac-like appearance, hence the name ‘sac brood'
• Infected larvae become 'banana' shaped with the head raised towards the top
of the cell opening
• They change from glistening white to grey or pale yellow, later turning brown
and finally black. The head usually blackens first
• Caps may be perforated or totally removed
• Death occurs on ninth day i.e. on second day after sealing of brood
• The dead prepupae became soft and boat-shaped scales, easily removable
• Odorless
• No ropiness

22. Sac brood

23. Sac brood symptoms

24. Management
• Keep colonies strong and unite weak colonies
• Isolate infected colonies, control robbing and drifting of bees
• Do not exchange infected frames from infected colonies to healthy ones
• Re-queening with a queen from a virus-free colony
• Destroy weak colonies and colonies with a high proportion of diseased
brood
• Do not feed the bees mouldy pollen, and do not breed bees on mouldy
combs
• Breeding disease-resistant strains of bees
• Maintain proper ventilation
• Burn and bury the bees in hive
• Discard infected frames
• Avoid migration of bee colonies

25. II. ADULT BEE DISEASES
 Nosema disease/Nosemosis
Causal organism: Protozoan, Nosema apis Zander
 Amoeba disease/Amoebiasis
Causal organism: Amoeba, Malpighamoeba mellificae Prell
 Acarine/Acarosis
Causal organism: Tracheal mite, Acarapis woodi (Rennie)
MAJOR DISEASES OF HONEY BEE

26.  Viral Diseases are caused by
 Chronic Bee Paralysis Virus (CBPV)
 Deformed Wing Virus (DWV)
 Black Queen Cell Virus (BQCV)
 Acute Bee Paralysis Virus Complex
̶ Acute Bee Paralysis Virus (ABPV)
̶ Kashmir Bee Virus (KBV)
̶ Israeli Acute Paralysis Virus (IAPV)

27. Nosema/Nosemosis
• Causal organism: Protozoan, Nosema apis and Nosema ceranae
• Their spores germinate in the ventriculus of the host
• Nosema disease affects a bee’s mid gut
• Hypopharyngeal glands of the diseased bee are atrophied
• Colony strength dwindles down
• Infection spreads through ingestion of food contaminated with
fecal matter

28. Symptoms: Nosema
• Affect all the castes
• Bees start foraging at younger age
• Infected queen stops egg laying
• Bees feel fatigued, are less able to fly and fall down during their return
journey
• Bees crawl up the grass blades and fall down on the ground
• Such affected fatigued bees gather in depressions/ditches
• The mid-intestine is swollen and, if dissected, shows dull greyish-white
contents
• The abdomen is distended with fecal matter
• Body hairs are lost and bees become shiny
• Bees soil the hive entrance

29. Nosemosis
a) Bees with swollen
abdomen
b) Dead bees
c) Healthy and infected
ventriculus
d) Spots of fecal matter
on the hive

30. Amoebiasis
• Causal organism: Amoeba, Malpighamoeba mellificae
• Not prevalent in tropical and sub-tropical regions
• Amoebiasis affects a very low proportion of colonies and is rarely
identified
• The infection is caused by ingesting the
• cysts along with contaminated food
• Cysts germinate, and amoeba migrates to malpighian tubes and feeds on
cell contents.
• Malpighian tubules of worker bees are most prone to being infected

31. Symptoms
• Diarrhea
• Bees feel fatigued, wing trembling and are unable to fly
• Such affected fatigued bees gather in depressions/ditches
• The abdomen is distended with fecal matter
• Body hairs are lost and bees become shiny
• Transmitted through drifting of bees, robbing, feed and water sources

32. Amoebiasis

33. Management
• Keep colonies strong and unite weak colonies
• Isolate infected colonies, control robbing and drifting of bees
• Do not exchange infected frames from infected colonies to healthy ones
• Re-queening with a queen from a virus-free colony
• Breeding disease-resistant strains of bees
• Maintain proper ventilation and less humid conditions
• Maintain colony hygiene and avoid over crowding
• Fumigation of infested combs with 98% acetic acid @ 2 ml/100 cc
• Feed Fumagilin (Fumidil-B) in concentrated syrup
• Avoid migration of bee colonies
• Provide fresh running water
• Drain off stagnant water from the apiary
• Scarp off the bottom board and disinfect it with 2% carbolic acid

34. Chronic Bee Paralysis (CBP)
• Causal organism: CBPV
• First viruses isolated from adult honey bees
• CBPV mainly attacks adult bees and causes two forms of ‘paralysis’
symptoms in bees.
– One is characterized by an abnormal trembling of the body and wings,
crawling on the ground due to the flight inability, bloated abdomens,
and dislocated wings
– Second form is identified by the presence of hairless, shiny, and
black-appearing bees that are attacked and rejected from returning to
the colonies at the entrance of the hives by guard bees
• CBPV to spread from diseased bees to healthy bees via their exposed
epidermal cytoplasm

35. Symptoms: CBPV
• CBPV infected bees are characteristically ‘shiny and black’
• These bees in infected hives are often found isolated, motionless
and/or shaking on the top bars
• When the colony is smoked they do not tend to move down
between the frames as the other ‘normal’ bees do.
• Abdomens may also be distended and the wings dislocated
• They can’t fly
• Seen crawling in front of the hives

36. CBPV

37. • Causal organism: CBPV
• It is transmitted by Varroa destructor
• In heavily Varroa infested colonies, nearly 100 percent of adult workers
may be infected with DWV
• DWV can be found in all castes and life stages of honey bees
• DWV is also transmitted through food, feces, from queen to egg, and
from drone to queen
Deformed/K-Winged adults

38. Symptoms: DWV
• Early death of pupae
• Deformed wings
• Shortened abdomen
• Cuticle discoloration in adult bees
• Bees die within 3 days causing the colony to eventually collapse
• Not all mite infested pupae develop these symptoms, but all adult honey bees
with symptoms develop from parasitized pupae
• Manage varroa to manage DWV

39. DWV

40. • Causal organism: BQCV
• It is transmitted by Varroa destructor
• K-wing, where the wing pair is disjointed and more perpendicular to
one another
• Queen pupae with symptoms display a pale yellow sac-like skin similar
to sac brood
• The pupae rapidly darken after death and turn the wall of the queen cell
dark brown to black.
• BQCV can be found in all castes and life stages of honey bees
• BQCV is also transmitted through food, feces, from queen to egg, and
from drone to queen
Black Queen Cell

41. • Early death of pupae
• Deformed wings
• Cuticle discoloration in adult bees
• Manage varroa to manage BQCV
Symptoms: DWV

42. • Acute Bee Paralysis Virus (ABPV)
Rapid mortality of bees compared to CBPV
Pupae infected with ABPV die before emerging
• Kashmir Bee Virus (KBV)
When KBV is injected in to adult bee hemolymph, death occurs in just 3 days
• Israeli Acute Paralysis Virus (IAPV)
Rapid mortality of bees compared to CBPV
ALL ARE TRANSMITTED BY Varroa MITE
Acute Bee Paralysis Virus Complex