Bunyaviral diseases Flashcards
Akabane Disease
Species Affected
Ruminants (cattle, sheep, goat)
Several other mammalian species
Akabane Disease
Occurrence
Tropics
Japan, South East Asia, Africa, Australia, Turkey
Akabane Disease
Spread
Mosquito borne
Akabane Disease
Clinical Signs
In ruminants:
• Abortion, miscarriage, premature birth
• Foetal arthrogryposis, hydrancephaly, muscle dystrophy
Akabane Disease
Diagnosis
Virus isolation
RT-PCR
Serology: VN, ELISA, IF
Akabane Disease
Prevention and Immunity
In enzootic regions: Attenuated and inactivated vaccines
Aino Virus
Species Affected
Cattle and Sheep
Also goats, buffalo, wild ruminants and humans
Aino Virus
Occurrence
Tropics
Asia and Australia
Also Japan
Aino Virus
Spread
Mosquito and Gnat borne
Aino Virus
Clinical Signs
Congenital malformation and birth defects in calves, infected in utero between the 120-180 days of pregnancy
• Arthrogryposis, scoliosis, sunken eyes, cataracts, dental irregularities, hydrancephaly, cerebellar symptoms
• Weakness, blindness, poor eyesight, neurological symptoms (ataxia, torticollosis, tetany, paresis, opisthotonus circling etc
No signs in adults, dairy cows have sudden astasia and leukopenia
Stillbirths, premature delivery
Aino Virus
Prevention and Immunity
Inactivated combined vaccine in Japan
Shamonda Virus
Species Affected
No direct evidence for pathogenicity in animals and humans
Shamonda Virus
Occurrence
Tropics
Shamonda Virus
Spread
Arthropod borne
Shamonda Virus
Clinical Signs
Seropositivity in colostrum free calves with
arthrogryposis and hydrancephaly
Schmallenberg Virus
Species Affected
Ruminants (sheep, cattle, goats)
Potentially zoonotic
Schmallenberg Virus
Occurrence
Europe
Germany, Netherlands
Schmallenberg Virus
Spread
By Cuilcoides midge
Schmallenberg Virus
Clinical Signs
Clinical manifestation only seen in
pregnant animals —> adult signs show few/no CS
Pregnant animals: virus spreads to developing foetus —> attacks brain and spinal cord —> damage to CNS and congenital deformities
Cattle:
• Fever (40.5℃)
• Anorexia, Diarrhoea
• Loss of condition and drop in milk production by 50%
• Congenital malformations are rare
Sheep:
• Fever (40.5℃)
• Congenital disorders very characteristic:
• Abortion, stillbirth, premature birth
• Lambs are sometimes born alive but not viable
• Malformation of limbs (torsion) and scoliosis (humpy back), ankylosis (bent spine), brachygnathia inferior
• Cerebellar hypoplasia, aplasia —> empty skull
• Enlarged thymus
Schmallenberg Virus
Diagnosis
RT-PCR
Isolation
Virus neutralisation and indirect IF
Schmallenberg Virus
Prevention and Immunity
Notifiable in Hungary
Banning on Dutch breed heifers
Ban on bovine semen and embryos from the Netherlands
Rift Valley Fever
Species Affected
Ruminants
Humans —> Zoonotic
100% mortality in young ruminants, dog puppies, kittens
Severe disease, abortion and death in sheep, cattle, goat and human
Severe disease and abortion in monkey, camel, rat and squirrel
Resistance in rabbit, swine, certain rodents, birds
Rift Valley Fever
Most susceptible
Young animals
Rift Valley Fever
Occurrence
Geographic Disease!
Primarily restricted to Africa and Arabian countries next to Africa
Rift Valley Fever
Spread
Primary vectors: Aedes mosquitos
• Germinative transmission
• Eggs survive for years
• Large scale hatching after heavy rainfall —> huge, infected mosquito population
• Seasonal infection Secondary vectors: Culex and Anophelers mosquitos, sandflies, blackflies, midges
Mosquitos in Europe are able to transfer the disease
Can also be transmitted by direct contact with tissues
and body fluids of infected animals, aborted foetuses,
slaughtering and dissections
Indirect transmission —> airborne infection
Rare Human to Human transmission
Rift Valley Fever
Clinical Signs
Sheep and Goat: • Incubation period of under 3 days • 5-100% of infected animals will abort during any stage of pregnancy • Sudden death • Diarrhoea, icterus • Mucopurulent nasal discharge • Subclinical infections can also occur • Lambs, kids: • High fever, depression anorexia • Death within 12-48 hours • Under 1 week of age: > 90% lethality • Over 2 weeks of age: 20% lethality Cattle: • Fever, weakness, anorexia, salivation, diarrhoea, icterus • Abortions in up to 100% of cases • Lethality : 10% • Calves: • Similar to lambs • 10-70% lethality Humans: • Incubation period of 2-6 days • Average mortality of 1% • Subclinical or influenza-like symptoms • Headaches, fever, vascular pain, nausea, vomiting • Recovery after 3-7 days • Retinopathy: • 1-3 weeks after acute symptoms • Conjunctivitis, photphobia • May lead to blindness • Hemorrhagic fever: • 2-4 days after febrile phase • Melena, haematemesis, petechia, icterus, shock, coma • 50% lethality • Encephalitis: • 1-3 weeks after acute phase • Sometimes together with hemorrhagic fever • Meningitis and encephalitis —> heavy incoordination and swelling
Rift Valley Fever
Pathology / Histopathology
Necrotic hepatitis —> enlarged, yellow, friable liver
Petechial haemorrhages in visceral organs and on mucosal surfaces due to blood clotting
Hemorrhagic enteritis in large intestins
Hydrothorax and Ascites
Rift Valley Fever
Diagnosis
Virus isolation
RT-PCR
Serology: ELISA
Disease is notifiable!
Rift Valley Fever
Treatment
Humans:
Symptomatic and supportive therapy
Provide coagulation factors
Ribavirin may have beneficial effect
Rift Valley Fever
Prevention and Immunity
Vaccination only allowed in endemic regions
• Mouse-Brain attenuated vaccine is foe to pathogenic
• Cell-culture attenuated vaccine induces short
protection
• Consider maternal antibody protection of the lambs/
calves
• Repeated vaccination with inactivated vaccine —>
protection for 1 year
Arthropod control
Personal protection (protective garments, gloves)
Prevent introduction of disease free countries:
• Quarantine, serological investigations
• Tourists
Nairobi Sheep Disease
Species Affected
Sheep
In local breed milder disease
Humans —> Zoonoitc
Nairobi Sheep Disease
Occurrence
Middle and East Africa
Nairobi Sheep Disease
Spread
Via Rhipicephalus
appendiculatus tick —> carries virus for years
Nairobi Sheep Disease
Pathogenesis
Injected directly in circulation —> viraemia —> spreads everywhere
Nairobi Sheep Disease
Clinical Signs
Incubation period of 4-15 days Fever, dyspnoea, depression, mucoprurulent nasal discharge, respiratory symptoms Hemorrhagic enteritis Abortion, oedema of genitals Shock Death (up to70-90% mortality) Humans: mild fever and generalised symptoms, mild respiratory signs
Nairobi Sheep Disease
Pathology / Histopathology
Hemorrhagic gastroenteritis Haemorrhages in heart Enlarged liver, kidneys, spleen, lymph nodes Full gall bladder Hyperaemic genitals
Nairobi Sheep Disease
Diagnosis
Occurence, clinical signs and
PM lesions
Virus isolation, RT-PCR, IF, AGID
VN
Nairobi Sheep Disease
Prevention and Immunity
Tick control
Vaccination in endemic areas:
• Attenuated, residual
virulence, risk of reversion
Crimean-Congo
Hemorrhagic Fever
Species Affected
Humans
Crimean-Congo
Hemorrhagic Fever
Occurrence
Asia and Africa
Crimean-Congo
Hemorrhagic Fever
Clinical Signs
Haemorrhages under skin, rash
Nephritis
Hemorrhagic Fever with
Renal Syndrome
Species Affected
Humans
Hemorrhagic Fever with
Renal Syndrome
Spread
Rodent reservoir
Tick borne
Hemorrhagic Fever with
Renal Syndrome
Clinical Signs
Influenza-like symptoms
Proteinuria
Hemorrhagic Fever with
Renal Syndrome
Pathology / Histopathology
Peritoneal oedema, myocardial haemorrhage
Hyperaemic kidneys with haemorrhages and necrosis
Haemorrhages and necrosis in frontal hypophysis
Hemorrhagic Fever with
Renal Syndrome
Diagnosis
RT-PCR
Virus isolation
Serology: ELISA, IF
Hemorrhagic Fever with
Renal Syndrome
Treatment
Symptomatic treatment
Hemorrhagic Fever with
Renal Syndrome
Prevention and Immunity
Stamping out of infected pet rodents
Control of breeders
Avoid contact with wild rodents
