72. Rinderpest, peste des petits ruminants.

Question 1

Rinderpest History?

Answer 1

Rinderpest (Cattle Plague)

History

• Devastating outbreaks
• Foundation of veterinary schools
• OIE founded 1924
• Global eradication 2011

Question 2

Etiology of Rinderpest?

Answer 2

Etiology

• Rinderpest virus
• Uniform virus (antigen structure), 3 genetic lines
• Low resistance
• Host range: cattle, other ruminants, swine
• Adaptation to new hosts: PPR, measles

Question 3

Epidemiology of Rinderpest?

Answer 3

Epidemiology

• Maintained by cattle
• Virus shed in excretes (during incubation)
• Direct contact of herds: market, drinking wells
• Transmitted in frozen meat
• Short survival in environment
• Morbidity: 100%, Mortality: 40-90%

Question 4

Pathogenesis?

Answer 4

Pathogenesis

1. Infection PO
2. Replication in lymph nodes around throat
3. Viraemia ➝ spleen, bone marrow, lymph nodes, mucous membranes ➝ leukopenia, inflammation of mucous

membranes, necrosis, erosions

4. Lifelong immunity
5. Sterile healing

Question 5

Clinical signs of rinderpest?

Answer 5

Clinical signs

• Acute (classical) form

‣ Incubation: 3-9 days

‣ Febrile phase: 41-41.5℃, depression

‣ Erosive phase

๏ Lacrimation, nasal discharge

๏ Nose, oral cavity: epithelial necrosis, erosions

‣ Diarrhoetic phase ➝ diarrhoea (mucous, blood, epithelial tissue debris), dehydration

• Peracute form

‣ Newborn animals, young calves

‣ Fever, death within 2-3 days

• Subacute (endemic) form

‣ Milder fever (38-40℃)

‣ Mild, serous nasal discharge, lacrimation

‣ Generally no diarrhoea

‣ Better general state, low mortality

• Sheep, goat ➝ milder, diarrhoea, without lesions on mucous membranes
• Swine ➝ fever, erosions, diarrhoea, death

Question 6

Pathology of Rinderpest?

Answer 6

Pathology

• Epithelium of digestive tract and upper respiratory tract

‣ Congestion, haemorrhages

‣ Necrosis, erosions, fibrinous pseudomembrane

‣ Hyperaemia, blackening of folds in large intestine

• Lymph nodes ➝ enlargement, oedema
• Peyer’s patches ➝ focal necrosis
• Histopathology

‣ Necrosis of lymphoid and epithelial tissue

‣ Cytoplasmic inclusion bodies, syncytia

Question 7

Diagnosis and differential of Rinderpest?

Answer 7

Diagnosis

• Epidemiology, clinical signs, pathology
• Virus detection

‣ Isolation of virus

‣ Detection: AGID, IHC, PCR, ELISA, chromatography

• Antibody detection: VN, ELISA
• Differential diagnosis

‣ Cattle ➝ FMD, malignant catarrhal fever, BVD, blue tongue

‣ Sheep ➝ PPR, Nairobi disease

‣ Swine ➝ swine dysentery

Question 8

Prevention, Control of rinderpest?

Answer 8

Prevention, Control

• Notifiable disease
• Successful eradication

‣ Low resistance of virus

‣ No long carriage, sterile recovery

‣ Effective vaccine: Live vaccine, lifelong production

• International strategic plan
• In case of outbreak ➝ closed herds, stamping out
• Serological monitoring programmes (sentinels)
• Safety vaccine (live attenuated) is in stock

Question 9

Peste des petits ruminants Occurrence?

Answer 9

Peste des Petits Ruminants (PPR)

Occurrence

• Africa
• Middle East
• India, Pakistan, China, Mongolia

Question 10

PPR ethiology?

Answer 10

Etiology

- PPR virus

• Relationship with Rinderpest virus
• 1 serotype
• 4 genetic lineages
• Host range

‣ Goat, sheep, Indian buffalo, gazella species

‣ Cattle: seropositivity

Question 11

Epidemiology of PPR?

Answer 11

Epidemiology

• Transmission by direct contact ➝ market, animal movement
• Excretes contain the virus in large amount
• The virus is shed before the appearance of clinical signs
• More frequent in rainy season and in dry cold weather
• Morbidity: 90-100%, Mortality: 50-100%
• No long carriage

Question 12

Pathogenesis of PPR?

Answer 12

Pathogenesis

1. Infection PO and inhalation
2. Viraemia
3. Replication in epithelium of mucous membranes and lymphoid cells
4. Immunosuppression
5. Good immunity and sterile recovery

Question 13

Clinical signs of PPR?

Answer 13

Clinical signs

• Incubation: 4-6 days
• Acute form

‣ Fever 40-41℃

‣ Serous, purulent nasal discharge, cough, conjunctivitis

‣ Necrosis of oral epithelium, erosions, bloody diarrhoea

‣ Laboured breath

‣ Abortion

• Peracute form: Goat ➝ fever, depression, death
• Subacute form ➝ mild nasal discharge, diarrhoea

Question 14

Pathology of PPR?

Answer 14

Pathology

• Oral cavity, nose: ulcerative inflammation, haemorrhages
• Gut: haemorrhages, necrosis, ‘zebra stripes’
• Lung: interstitial pneumonia

Question 15

Diagnosis and DD of PPR?

Answer 15

Diagnosis

• Epidemiology, clinical signs, pathology
• Agent detection: virus isolation, AGID, ELISA (monoclonal), PCR
• Antibody detection: ELISA, VN

DD:

1. Rinderpest,
2. Bluetongue,
3. orf,
4. FMD,
5. contagious caprine pleuropneumonia,
6. Pasteurellosis

Question 16

Prevention and control of PPR?

Answer 16

Prevention, Control

• Endemic area

‣ Closed herds, movement restrictions

‣ Vaccine: attenuated

‣ Vaccinated above 3 months of age, 3 year long protection

• Disease-free area

‣ Prevention of introduction

‣ Monitoring

‣ In case of outbreak: closed herds, stamping out, strategic ring vaccination (special permission)

• Eradication