Bunyviridae

1
Bunyviridae

• Sperical, segmented negeaive sense ssRNA genome
• Cytoplastic replication

2
Rift Valley Fever - RVF

• Acute, arthropod virus, sheep, goats, cattle and
  humans
• ZOONOTIC
• Distribution endemic certain parts of Africa
• Etiologic agent Phlebovirus one serotype
• Replication fast, high titer rapidly cytopathic
• Transmission mosquito tranmission culex and
  aedes
• Interepidemic maintainanc transovarial
  transission in Aedes mosquitoes
• Rainiy seasons infected mostyties develop and
  transmit the vfirs to ruminbants amplifying the
  virus
• Mechanical gtransission culicadea and
  sandfluies
• Aerosol transission in humans

3
Rift Valley Fever

• Pathogenesis arthropod inoculation or via
  oropharynx, primary viremia for 2-5 days
• Replication in the liver and reticuloendothelial
  organs leading to widespread cytopatholgoy,
  massive necrosis of the liver
• Clinical Features IP 30-72 hours
• Sheep and goats fever, anorexia, bloody
  diarrhea, mucopurulent nasal discharte
• 90-100 pregnant females abort ABORTION STORM
• Surviving animals may show encephalitis
• Mortalitiy in kidis and lamnbs approaches 90 -
  20-60 in adult sheep and goats

4
Rift Valley Fever

• Cattle disease less severe 90-100 of
  pregnant cows abort
• Mortality rate in calves and cows 10-30
• Diagnosis clinical signs, virus isolation and
  seroconversion
• Virus can be isolated in mice or cell culture
• Serology IgM capture enzyme immunoassay on
  single acute sera, ELISA, virus neutralization
  test, HIA
• Prevention and control vaccination with
  attenuated and inactivated vaccines
• Humans infectde by aerosola dn sduring the
  slaughter of viremic aniamsl
• Resemble influenza or dengue fever, sudden onset,
  chills, fever, malaize, headache, vomiting, may
  last for 4-6 days mortality rate approaches 10
• INACTIVATED VACCINE FOR THOSE AT RISK

5
Akabane disease

• Congenital disease of cattle, sheep, goats
• Arthrogryposis and hydrancephaly
• Distribution Australia, Japan, Israel, Turkey,
  isolated in Kenya, South Africa
• Etiologic agent Bunyavirus
• Transmission aedes, culex, culicoides
• Pathogenesis virus carried to placenta by
  maternal circulation, infects fetus NO DISEASE
  IN THE DAM
• Main fetal infection is encephalomyelitis and
  polymyositis, severe infection death and
  abortion
• Surviving animals arthrogryposis,
  hydrancephaly, cavitations of the cerebrum,
  torticollis, scoliosis, kyphosis

6
Akabane Disease

• Diagnosis pathologic and serologic evidence
• Pathology brain, cervical, thoracic and lumbar
  region of the spinal caord and submitted in 10
  formalin for histologic examination
• Serology presence of virus neutraliziaing
  antibodies in aborted fetuses or in precolostrum
  serum sample from the affected offspring
• Prevention vaccine available in Japan and
  Australia inactivated