Lecture 10 - Aujeszky's disease, Japanese encephalitis

Question 1

ADV stands for?

and give two alternative names

Answer 1

Aujeszky disease virus

Pseudorabies
Mad itch

Question 2

AUJESZKY’S DISEASE is a contagious disease of

Answer 2

pigs,
caused by herpesvirus, characterized by CNS signs and high mortality in young animals, and respiratory illness in older pigs.

Question 3

AUJESZKY’S DISEASE is a contagious disease of pigs, caused by herpesvirus, characterized by

Answer 3

CNS signs and high mortality in young animals,

and respiratory illness in older pigs.

Question 4

Causative agent of Aujeszky’s disease (ADV).

Answer 4

Aujeszly’s disease virus which belongs to:
Genus Varicellovirus,
family Herpesviridae

Question 5

ADV type of virus?

Answer 5

DNA virus

only 1 serotype

Question 6

Host range of ADV.

Answer 6

mammals but clinical cases affect pigs.

Pigs are Natural hosts and the only animals to become latent carriers.

Question 7

Distribution of ADV.

Answer 7

Europe, Southeast Asia,
Central and South America-

Eradicated in some countries (e.g. New Zealand).

Question 8

Morbidity of ADV.

Answer 8

Morbidity <100%

Question 9

Mortality of ADV.

Answer 9

Mortality: increases the younger the piglet.

1-2% grower and finisher pigs
5-10% weaner pigs
50% in nursery pigs
<100% piglets less than one week old

Question 10

Excretion of ADV.

Answer 10

tonsillar epithelium,
milk, urine and vaginal and preputial secretions

Question 11

Transmission of ADV.

Answer 11

Direct transmission
Aerosols
Fomites
In utero

Route: respiratory and oral

Question 12

IP of ADV.

Answer 12

suckling pigs 2-4 days,
weaned and adults 3-6 days

Question 13

Clinical signs of ADV in piglets less than 1 week old.

Answer 13

Fever, listlessness and anorexia then tremors, paddling, seizures or other symptoms of CNS involvement.

“Dog-like” sitting position (due to hindleg paralysis).

May die within hours,
usually in 24-46 hours – high mortality in newborn piglets.

Question 14

Clinical signs of ADV in weaners.

Answer 14

Mainly respiratory illness: fever, anorexia, weight loss, coughing, sneezing, conjunctivitis and dyspnea.

May be complicated by secondary bacterial infections.

Recovery 5-10 days.

Question 15

Clinical signs of ADV in adult pigs.

Answer 15

Infection usually mild or inapparent with respiratory symptoms.

Question 16

Clinical signs of ADV in cattle & sheep.

Answer 16

Almost always fatal within few days

Intense pruritis, CNS signs

Question 17

Post mortem lesions of ADV.

Answer 17

Lesions often subtle or absent.

Serous or fibroneurotic rhinitis.

Pulmonary edema, congestion, consolidation.

LNs – congested and hemorrhagic

Necrotic foci in other organs

Question 18

Suspect ADV when…?

Answer 18

high mortality and CNS signs in young piglets,

and lower mortality and respiratory signs in older animals.

Question 19

Material for diagnosis of ADV. (3)

Answer 19

Nasal swabs

Oropharyngeal fluid, biopsies of the tonsils

Brain and tonsils

Question 20

Lab analyses for diagnosis of ADV. (3)

Answer 20

Virus isolation

Detection of viral DNA or antigens by immunofluorescence, immunoperoxidase, virus neutralization assays or PCR.

Serology – virus neutralization, latex agglutination, ELISA.

Question 21

Treatment of ADV.

Answer 21

no treatment, viral

Question 22

Prevention & control of ADV.

Answer 22

Quarantine & disinfection

Vaccination protects pigs from clinical signs and decrease viral shedding, but does not provide sterile immunity or prevent latent infections.

Question 23

Eradication strategies for ADV. (3)

Answer 23

Test and remove
Offspring segregation
Depopulation

Question 24

JEV stands for?

Answer 24

Japanese encephalitis virus

Question 25

Give 4 alt. names for JEV.

Answer 25

Japanese encephalitis virus alt. names: Japanese B Encephalitis Mosquito-born Encephalitis Brain Fever Summer Encephalitis

Question 26

JAPANESE ENCEPHALITIS is a disease caused by

Answer 26

a mosquito-borne flavivirus associated with reproductive losses in pigs and encephalitis in horses and people. despite being vector-borne is still contagious!!

Question 27

JAPANESE ENCEPHALITIS is a disease caused by a mosquito-borne flavivirus associated with (2)

Answer 27

reproductive losses in pigs and encephalitis in horses and people.

Question 28

Causative agent of JEV. And which family/genus?

Answer 28

Japanese encephalitis virus belonging to Genus Flavivirus, family Flaviviridae

Question 29

JEV viral type? serotypes?

Answer 29

RNA virus One serotype

Question 30

Stability of JEV. (3)

Answer 30

Virus very labile and does not survive well in the environment. Sensitive to UV Inactivated in pH 1-3

Question 31

Main host range of JEV. (4)

Answer 31

horses (primary affected domestic animals but a dead-end host), donkeys pigs (amplifiers) humans (dead-end host) birds: herons and egrets (reservoirs) Can also infect: cattle, sheep, goats, dogs, cats, chicken, ducks, wild mammals, reptiles and amphibians but is SUBclinical in these.

Question 32

Distribution of JEV

Answer 32

endemic in Asia: Japan, India has jumped to Australia too

Question 33

Morbidity of JEV in horses swine humans

Answer 33

horses < 2% swine < 100% humans 5-35%

Question 34

Mortality of JEV in horses swine humans

Answer 34

horses 5-40% swine death is rare humans 5-35%

Question 35

Excretion of JEV.

Answer 35

swine: oronasal secretions (between 2 and 8 days post infection), urine, sperm dead-end hosts do not transmit of course.

Question 36

Transmission of JEV.

Answer 36

By mosquito vectors via bite But also, Direct contact – droplets Indirect contact via insects moving it. Iatrogenic Routes: respiratory (inhalation) in utero (not common) cutaneous

Question 37

JEV: Natural infection contributes to long lasting immunity in

Answer 37

adult pigs and surviving piglets

Question 38

IP of JEV

Answer 38

In horses: 4-14 days, mostly subclinical though. In pigs: 3-4 days In humans: 5-15 days

Question 39

3 forms of JEV

Answer 39

transitory form lethargic form hyperrexcitable form

Question 40

Describe the Transitory form of JEV in horses.

Answer 40

Fever (2-4 days), anorexia Impaired locomotion, congested or jaundiced mucosa Recovery 2–3 days

Question 41

Describe the lethargic form of JEV in horses.

Answer 41

Febrile periods, stupor, bruxism and chewing motions, difficulty in swallowing, incoordination, evidence of neck rigidity, impaired vision, paresis and paralysis. Petecchiation of mucosa Recovery within a week

Question 42

Describe the hyperexcitable form of JEV in horses.

Answer 42

Pyrexia, profuse sweating and muscle tremors, aimless wandering, aggression, loss of vision, collapse, coma and death.

Question 43

Clinical signs of JEV in Swine.

Answer 43

Mild febrile disease or subclinical disease in non-pregnant females. Reproductive disease ((50-70%) abortion, stillbirths etc.) Congenital: tremors, convulsions, death soon after birth. Suckling piglets and weaners: wasting, depression or hindlimb paralysis may be seen in suckling piglets and weaner pigs. Boars: infertility and edematous, congested testicles.

Question 44

Clinical signs of JEV in humans.

Answer 44

Less than 1% of people develop neurologic illness. Fever, headache, vomiting. Mental status changes, neurologic symptoms, weakness, movement disorders, sensitivity to light, neck stiffness. Seizures are common, especially among children 20% – 30% among patients with encephalitis die 30%-50% of survivors continue to have neurologic, cognitive, or psychiatric symptoms Abortions

Question 45

Post mortem lesions of JEV in pigs.

Answer 45

Subcutaneous edema, and hemorrhages, hydrocephalus, encephalitis, cerebellar hypoplasia Congestion in the lung, liver, heart, spleen and lymph nodes Multifocal hepatic and splenic necrosis

Question 46

Post mortem lesions of JEV in horses.

Answer 46

Nonspecific lesions of CNS that are usually only microscopic NOT macro: diffuse non-suppurative encephalomyelitis with apparent perivascular cuffing phagocytic destruction of nerve cells, perivascular cuffing focal gliosis blood vessels appear dilated with numerous mononuclear cells

Question 47

Material for diagnosis of JEV. (4)

Answer 47

Brain, spinal cord, tonsils, oral fluid CSF, Blood Aborted fetuses, placenta Thoracic fluid from aborted fetuses up to 70 days of age.

Question 48

Lab analyses for diagnosis of JEV. (3)

Answer 48

Virus isolation Detection of viral DNA or antigens by RT-PCR, virus neutralization assays, Ag-ELISA. Serology: hemagglutination inhibition, ELISA.

Question 49

Tx for JEV.

Answer 49

none, viral

Question 50

Prevention & control of JEV. (5)

Answer 50

Housing animals in-doors Vector control: removal of stagnant water. Separate raising of swine near horses. Quarantine. Vaccination.

Question 51

Vaccination against JEV.

Answer 51

Immunization of swine because they are JE virus amplifiers to reduce amplification, ensure healthy litters and decrease likelihood of aspermia. Horses, humans: - Live modified - Inactivated - genotype mutation renders some vax nonefficacious