Viral diseases of poultry

2.  Acute pox viral disease of cattle manifested with sudden
appearance of nodules on the skin.

3.  Insect vectors by direct and indirect
transmission. Seasonal and geographic
distribution.

4.  Incubation: 4 – 14 days
 Fluctuating fever
 Diarrhoea
 Nasal discharge and salivation
 The first lesion appear in the perineum
 Various sized cutaneous nodules (Fig.) may occur
throughout the body
 Skin lesions may show scab formation
 Swelling of superficial lymph nodes and limbs,
and lameness
 Infertility and abortion
 Secondary infection may lead to joint and tendon
inflammation

5. Lumpy skin disease. Various sized cutancous
nodules in a severe case of lumpy skin disease.

6.  Ulcerative lesions in the mucosa of the
respiratory and digestive tract
 Reddish, haemorrhagic to whitish lesions in
the lungs
 Edema (interlobular) and nodules in the lungs
(Fig.)
 Heart lesion (endocardium)
 Thrombosis of skin vessels followed by
cutaneous infarction and sloughing

7. Cut surface of the nodules in the parenchyma of
the lung and interlobular edema.

8. Allergies, screw-worm myiasis,
urticaria, dermatophilosis (streptothricosis),
bovine herpes dermophatic infection,
cattle grubs, vesicular disease,
bovine ephemeral fever, photosensitization,
besnoitiosis (elephant skin disease),
sweating weakness of calves,
bovine farcy and
skin form of sporadic bovine lymphomatosis
https://www.youtube.com/watch?v=MIPAKL35FuI

9.  Carcass of an animal showing mild cutaneous
lesions and no fever associated with general
signs of infection is conditionally approved
pending heat treatment.
 The affected parts of the carcass and organs
are condemned.
 Carcass of an animal showing, on
antemortem examination, generalized acute
infection accompanied with fever, is
condemned.

10.  IBR is a highly infectious viral respiratory
disease of cattle, goats and pigs manifested
by inflammation of respiratory passages and
pustular lesions on the male and female
genital organs.
◦ Generally four forms of the disease are recognized;
 the respiratory form,
 the genital form,
 the enteric form and
 the encephalitic form.

11.  Transmission:
◦ Respiratory droplet and nasal exudate in the
respiratory form of IBR.
◦ Obstetrical operations, contact with genitalia of
affected animals in the genital form of disease.

12. Respiratory form
 Incubation: 5 – 14 days
 Fever
 Nasal and ocular discharge and red, swollen
conjunctiva
 Drop in milk yield
 Breathing through the mouth and salivation
 Hyperaemia of the nasal mucosa and necrotic
areas on the nasal septum
 Secondary bronchopneumonia
 Abortion

13.  Genital form
◦ Frequent urination and tail elevation
◦ Edematous swelling of the external genitalia and
pustule formation on reddened vaginal mucosa
◦ Mucoid or mucopurulent exudate in the vagina
 Enteric form
◦ Severe oral and stomach necrosis in new born
animals
◦ High mortality

14.  The encephalitic form in calves
◦ Depression, Excitement, High mortality

15. Breathing through the mouth and salivation in a
bovine affected with IBR.

16.  Postmortem findings:
◦ Acute inflammation of the larynx, trachea and bronchi
◦ Profuse fibrino-purulent exudate in the upper
respiratory tract in severe cases
◦ Chronic ulcerative gastro-enteritis in feedlot cattle
◦ Lung emphysema
◦ Secondary bronchopneumonia

17. IBR. Acute inflammation of the larynx and trachea

18.  Judgement: Carcass of an animal affected
with IBR is approved if signs of acute infection
are not present and the animal is in good body
condition.
 Differential diagnosis: Pneumonic pasteurellosis,
bovine viral diarrhoea, malignant catarrhal fever
and calf diphtheria


19.  An infectious viral disease of cattle
manifested by an active erosive stomatitis,
gastroenteritis and diarrhoea.

20.  Transmission: Direct contact with clinically
sick or carrier animals, indirect contact with
feedstuffs or fomites contaminated with
urine, nasal and oral secretions or faeces and
contact with aborted fetuses.
 Transmission through aerosol droplet
dispersion or by insect vector may also be a
possibility.
 Virus may persist in recovered and chronically
ill cattle which are considered a potential
source of infection.

21.  Antemortem findings :
◦ Incubation: 1 – 3 days
◦ Fever
◦ Congestion and erosions in the mucous membranes
of the oral cavity
◦ Depression and anorexia
◦ Cough, polypnea and salivation
◦ Dehydration and debilitation
◦ Foul-smelling diarrhoea

22. ◦ Cessation of rumination
◦ Reduced milk supply
◦ Abortion in pregnant cows Laminitis Congenital
anomalies of the brain (cerebellar ataxia) and
arthritis in young calves

24.  Shallow erosions present on the entrance of
the nostrils, mouth, pharynx, larynx,
oesophagus, rumen (Fig.), omasum,
abomasum (Fig.), caecum and less frequently
in Peyer's patches in the small intestine.
 Erythema of the mucosa with submucosal
haemorrhage in the abomasum, small
intestine, caecum and colon.
 Stripped appearance on the caecal and colon
mucosa is similar to that seen in rinderpest.
 Cerebral hypoplasia and cataracts in calves

25. Congestion and erosions in the ruminal mucosa.

26. Inflammation of the abomasum (abomasitis, gastritis).

27.  Differential diagnosis :
◦ Malignant catarrhal fever,
◦ rinderpest,
◦ blue tongue and
◦ vesicular diseases (produce vesicles which are not
present in BVD).
 Diseases with no oral lesion nor diarrhoea
include salmonellosis, Johne's disease and
parasitism

28.  Carcass and viscera of an animal, which on
antemortem examination showed generalized
signs of acute infection accompanied with
fever and/or emaciation, are condemned.
 Chronic cases of BVD with no systemic
involvement have a favourable judgement of
carcass, viscera and organs.

29.  Coenurus cerebralis infection (Gid, Sturdy)
◦ Coenurosis is a disease of the brain and spinal cord
caused by the intermediate stage of Taenia
multiceps which inhabits the intestine of dogs, cats
and wild carnivores. The clinical disease occurs in
sheep and rarely in cattle.
◦ Judgement : Carcass affected with coenurosis is
approved. Affected brain and organs are
condemned.

30. Coenurus cerebralis. Thin walled cyst in the brain