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

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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

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History

• 1959– First isolated from mosquitoes in Japan

• 1969-70– Israel outbreak– 3,000 calves, 700 lambs, 600 kids

• 1972– First reported in Australia

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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

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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

euthanizedCenter 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

Center for Food Security and Public Health, Iowa State University, 2011

Arthrogryposis Microencephaly and Hydranencephaly

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 veterinarianhttp://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/

downloads/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