5. viral infections of honey bees Flashcards
Main causes of honeybee colony loss:
- parasite Varroa
- pesticides
- food shortage due to wildflower loss
Can viral infections be asymptomatic
yes
What can viruses infect?
- eggs
- larvae
- pupae
- adults
The way an infection can spread
horiztontally or vertically
Predisposing factors leading to viral infections
- crowded population
- stressful conditions eg due to Varroa mite infestation
what is dicistroviridae known by::
- acute bee paralysis
- israeli acute paralysis
- kashmir bee virus
- black queen cell
What is iflaviridae known by:
- deformed wing virus
- kakugo virus
- varroa destructor virus 1
- sacbrood virus
- slow bee paralysis virus
Taxonomically unclassified viruses
- chronic bee paralysis
- lake sinai viruses
3 types of single stranded RNA viruses
- dicistroviridae
- iflaviridae
- chronic bee paralysis
- lake sinai viruses
Double stranded DNA virus:
> 300 nm
Apis mellifera filamentous virus
Which bees does ABPV mainly affect
worker bees, larva too
How does ABPV infect
via salivary glands of infected adult bees
What is the vector of ABPV
Varroa destructor
Symptoms of ABPV
- no symptoms or trembling
- paralysis of wings and bodies with 2-4 days and death 1-2 days later
what happened to larvae of bees infected with ABPV?
if fed sufficiently with virus will die before sealed in their cells
Chronic bee paralysis affects
workers and pupae
Infection by CPV
via mouth/pore in cuticle left by broken hairs
Type 1 paralysis symptoms of CPV
- aka isle of wight disease
- trembling motion of wings and body
- bloated abdomens
- dysentery
Type 2 paralysis symptoms of CPV
- black robbers or little blacks
- guard bees prevent their return to colony like robber bees
Which bees are seemingly unaffected by the sacbrood virus
drones are seemingly unaffected and adults been without signs of the disease
Which bees are most susceptible to SBV
larvae of about 2 days old but older are most susceptible
Symptoms of SBV
larva lay along the base of the cell in a banana or gondola shape
Why do larvae die in SBV
unable to shed their last larval skin and fail to pupate due to fluid accumulation
Colour change of larvae affected with SBV
- from pearly white to pale yellow
- darkens around head and thoracic region when the larvae die
Infected bees with SBV
will fly and forage much earlier in life than usual but fail to collect pollen as the hypopharyngeal glands degenerate
What bees does the deformed wing virus affect
workers as well as in brood
Vector of deformed wing virus
Varroa destructor
Symptoms of DWV
- deformed or poorly developed shrunken wings
- decreased body size and discolouration in adult bees
Which bees does the cloudy wing virus affect
mainly in workers, brood too
Symptoms of cloudy wing virus
marked loos of transparency of the wings
Which bees does the kashmir bee virus affect
mainly workers and larvar
Symptoms of KBV
resembling an infection with american foulbrood or european foulbrood
can cause bee mortality within 3 days
Which bees does the black queen cell virus affect
- adult bees
- praepupae
what is the BQCV associated with
Nosema sp.
Symptoms of the BQCV
- Queen larva or pre-pupae die after they have been sealed
- dark brown or black queen cells containing dead prepupae
The only DNA virus we only know:
filamentous
Symptoms of filamentous virus
haemolymph becomes milky white
Characteristics pf chronic bee paralysis associate
- might be satellite of CPVA)
- more evident in queens than in workers
Bee virus X characteristics
- related to virus Y
- occurs in adults
- special association to malphighamoeba mellificae
Slow paralysis virus SYMPTOMS:
paralysis of the anterior two pairs of legs for a day or two before death
Israeli acute paralysis virus (IAPV) symptoms:
- paralysis
how do you diagnose viral infections
PCR
