Akabane
Congenital Arthrogryposis-Hydranencephaly Syndrome,
Acorn Calves, Silly Calves,
Curly Lamb Disease, Curly Calf Disease,
Dummy Calf Disease
Overview
• Organism
• Economic Impact
• Epidemiology
• Transmission
• Clinical Signs
• Diagnosis and Treatment
• Prevention and Control
• Actions to Take
Center for Food Security and Public Health, Iowa State University, 2011
THE ORGANISM
Center for Food Security and Public Health, Iowa State University, 2011
Akabane Virus
• Single stranded RNA virus
– Family Bunyaviridae
• Genus Orthobunyavirus
• Sheep, goats and cattle
– Intrauterine infection of fetus
– No clinical signs in the dam
Center for Food Security and Public Health, Iowa State University, 2011
IMPORTANCE
Center for Food Security and Public Health, Iowa State University, 2011
History
• 1959
– First isolated from mosquitoes in Japan
• 1969-70
– Israel outbreak
– 3,000 calves, 700 lambs, 600 kids
• 1972
– First reported in Australia
Center for Food Security and Public Health, Iowa State University, 2011
Economic Impact
• High mortality to newborn and
fetal cattle, sheep and goats
• U.S. livestock greatly susceptible
• Potential vectors found in U.S.
• 2010 U.S. livestock statistics
– Calves: 35.4 million head
– Lambs: 3.6 million head
Center for Food Security and Public Health, Iowa State University, 2011
EPIDEMIOLOGY
Geographic Distribution
• Tropics and subtropics
• Australia, Japan, Israel, Korea
• Occasionally in Asia, the Middle East,
and South Africa
Center for Food Security and Public Health, Iowa State University, 2011
Morbidity/ Mortality
• Endemic areas
– Immunity by sexual maturity
– Seroprevalence 80%
• Greatest risk
– Naïve and susceptible animals
– Favorable environmental conditions
• High mortality in newborns
– Most die soon after birth or must be
euthanized
Center for Food Security and Public Health, Iowa State University, 2011
TRANSMISSION
Animal Transmission
• Vector-borne
– Mosquitoes
– Biting midges
• NOT transmitted by:
– Direct contact
– Infected tissues, exudates, body fluids
– Fomites
• Ruminants are not long-term carriers
Center for Food Security and Public Health, Iowa State University, 2011
ANIMALS AND AKABANE
Clinical Signs
• Cattle, sheep, goats
• Adults asymptomatic
• Pregnant ruminants
– Abortion and stillbirths
– Premature births
– Dystocia
• Congenital abnormalities
– Varies with stage of gestation
Center for Food Security and Public Health, Iowa State University, 2011
Congenital Abnormalities
• Early pregnancy
– Behavioral abnormalities
• “Dummy Calves”
– Skull deformities
• Second trimester
– Arthrogryposis (rigidly flexed joints)
– Severe muscle atrophy
– Torticollis, scoliosis, kyphosis
• Last trimester
– Bright and alert but unable to stand
– Ataxia, paralyzed limbs, muscle atrophy
Center for Food Security and Public Health, Iowa State University, 2011
Post Mortem Lesions
• Fetuses or newborns
Arthrogryposis
Microencephaly and
Hydranencephaly
Center for Food Security and Public Health, Iowa State University, 2011
Post Mortem Lesions
• Other congenital abnormalities
– Hydrocephalus, microencephaly, spinal
cord agenesis or hypoplasia, torticollis,
scoliosis, brachygnathism
– Cataracts, ophthalmia
– Hypoplastic skeletal muscles and lungs
– Fibrinous polyarticular synovitis
Center for Food Security and Public Health, Iowa State University, 2011
Differential Diagnosis
• Cache Valley virus infection
• Bluetongue
• Bovine viral diarrhea virus
• Border disease
• Wesselsbron disease
• Nutritional, genetic, or toxic diseases
Center for Food Security and Public Health, Iowa State University, 2011
Sampling
• Before collecting or sending any
samples, the proper authorities
should be contacted
• Samples should only be sent under
secure conditions and to authorized
laboratories to prevent the spread of
the disease
Center for Food Security and Public Health, Iowa State University, 2011
Diagnosis
• Clinical signs
• Laboratory Tests
– Serology
• From fetus or neonate
• Cerebrospinal fluid
• Adults: antibody titer or seroconversion
– Virus isolation and identification
– RT-PCR
– Immunofluorescent staining
Center for Food Security and Public Health, Iowa State University, 2011
Treatment
• No effective treatment
• Affected neonates should be
euthanized
• Subsequent pregnancies unaffected
Center for Food Security and Public Health, Iowa State University, 2011
AKABANE IN HUMANS
No human cases have
been reported
PREVENTION AND
CONTROL
Recommended Actions
• IMMEDIATELY notify authorities
• Federal
– Area Veterinarian in Charge (AVIC)
http://www.aphis.usda.gov/animal_health/area_offices/
• State
– State veterinarian
http://www.usaha.org/StateAnimalHealthOfficials.pdf
• Quarantine
Center for Food Security and Public Health, Iowa State University, 2011
Prevention
• Protection from vectors
– Mosquitoes and biting midges
• Vaccination
– Inactivated and attenuated vaccine
– Killed vaccine
– Not currently available in U.S.
Center for Food Security and Public Health, Iowa State University, 2011
Additional Resources
• World Organization for Animal Health
(OIE)
– www.oie.int
• U.S. Department of Agriculture (USDA)
– www.aphis.usda.gov
• Center for Food Security and Public Health
– www.cfsph.iastate.edu
• USAHA Foreign Animal Diseases
(“The Gray Book”)
– www.aphis.usda.gov/emergency_response/do
wnloads/nahems/fad.pdf
Center for Food Security and Public Health, Iowa State University, 2011
Acknowledgments
Development of this presentation was made possible
through grants provided to
the Center for Food Security and Public Health at Iowa
State University, College of Veterinary Medicine from
the Centers for Disease Control and Prevention,
the U.S. Department of Agriculture,
the Iowa Homeland Security and
Emergency Management Division, and the
Multi-State Partnership for Security in Agriculture.
Authors: Glenda Dvorak, DVM, MPH, DACVPM ;Anna Rovid Spickler, DVM, PhD
Reviewers: James A. Roth, DVM, PhD; Katie Spaulding, BS; Kerry Leedom Larson, DVM,
MPH, PhD
Center for Food Security and Public Health, Iowa State University, 2011