Viral disease's

1. BOVINE VIRAL DISEASES
Dr. NYONI H.

2. LUMPY SKIN DISEASE (LSD)
• This is highly infectious skin disease of cattle
characterized by the sudden appearance of
nodules on all parts of skin.
Etiology
• Family Poxviridae
• Genus Capri poxvirus
• Closely related to sheep and goat pox
• Cannot be differentiated with serology

3. EPIDEMIOLOGY
Host : All ages and types of cattle
Distribution : World wide
Transmission :
•Primary route: biting insects
•Minor route: direct contact
•Cutaneous lesions, saliva, nasal
discharge, milk, semen, muscles
•No carrier state

4. PATHOGENESIS
•After an initial viraemia accompanied
by a febrile reaction, localization in the
skin occurs with development of
inflammatory nodules.

5. Clinical signs
Incubation period is 2 to 5 weeks.
i. There is initial rise in temperature.
ii. Multiple nodules appear on the skin , they
are around and firm, and are flattened.
iii. Raised, circular, firm, coalescing nodules
- Common on head, neck, udder,
perineum, legs
- Cores of necrotic material called “sit-
fasts”
iv. Nodules may develop in the mucosa of
GIT, respiratory and genital tracts, which
late on ulcerate.

6. Clinical signs cont.
v. Rhinitis and conjunctivitis.
vi. Lymphadenitis may be present.
vii.Nodules may ulcerate and suppurative
materials fill the nodules.
viii.Mastitis may occur if udder is
involved
ix. Decreased milk production
x. Lameness
xi. Abortion and sterility

8. Post Mortem Lesions
•Characteristic skin nodules
•Lesions in the mucous membranes
throughout the
GI tract
•Nodules in lungs
•Hemorrhages in spleen, liver, rumen

9. Diagnosis
i. Clinical signs
ii. Serological testes: Fluorescent Antibody
tests
iii. Isolation of Virus
iv. Histopathological examination: presence of
inclusion bodies in section of nodule.
Treatment
 No specific treatment is available, but
prevention of secondary infection is
essential: Use of antibiotics eg. Penstrep

10. Control
•Immediately notify the authorities
•Vaccination of cattle with sheep poxvirus
vaccine.
•Quarantine and restriction of movement.
•Depopulation
•Proper carcass disposal
•Cleaning and disinfection

11. FOOT AND MOUTH DISEASE
(Syn.Contagious aphthae or Aphthous
fever)
•This is extremely contagious, acute
disease of all cloven-footed animals
characterized by fever, formation of
vesicles outside the mucosal membrane
in oral cavity, udder and interdigital
spaces. The disease has highest
morbidity and mortality rates in young
animals.

12. Aetiology
•A virus known as Aphthovirus of the
family Picornaviridae with 7 known
Serotypes named; A, O, C, SAT 1,
SAT 2, SAT 3 and Asia 1. There are
also many strains within serotypes. Each
strain requires a specific vaccine to
provide immunity to a vaccinated
animal.

13. Epidemiology
•Susceptibility; All cloven hoofed
animals are susceptible to this disease:
- Cattle (Calves more susceptible than
adults)
- Pigs
- Sheep
- Dear are most susceptible
- Goats (In apparent infections)
- Camel

14. Transmission
•The animal gets the infection through either
inhalation or ingestion of contaminated
material.
•The disease is spread from herd to herd or
animal to animal either directly or indirectly.

15. Direct Spread:
• By Contact between animals excreting the virus
and susceptible individuals. The viruses are
retained in the retropharyngeal region (in the
carrier animal) or salivary gland where secretion
in the environment is at maximum.
Indirect Spread:
• Contaminated materials with virus containing
secretions, excretions, tissues usually at
watering points, hay, beddings
• Animal products such as milk,
• Mechanical transmission/Iatrogenic (vets,
farmers via boots, vehicles).

16. Morbidity and Mortality rates
•Morbidity may approach 100%
depending on;
• level of immunity
• previous exposure to the virus strain/
subtype
• virus dose
• host species.

17. •Mortality rates are
low 2 – 3%, but
about 30%
mortality has been
recorded.
• Higher mortalities
occur in calves
due to myocarditis

18. Clinical signs
The incubation period ranges between 2 -
12 days.
•The onset of FMD is manifested by fall
in milk production (for lactating cows).
•High fever ( 40 - 41˚C ) that decline
rapidly after 2 – 3 days.
•Severe depression
•Acute painful stomatitis
•Anorexia

19. • Salivation: The saliva hangs in a long ropey
string and the animal chews with signs of
pain.
• Appearance of vesicles and sores on the
buccal mucosa, dental pad and the tongue.
The vesicles rupture within 24 hours and
leaving a wound which heals in about a
week.
• Sores and Blisters/vesicles on the teats and
on the interdigital space.

20. • Disinclination to stand
• Severe lameness
• Recumbence
• Swelling in the testicles of mature male
animals.
• Pregnant animals abort
• Sudden death in calves
• Recovered animals remain carrier with virus
localizing in the nasopharyngeal region:
Sheep and Cattle (1 month and 9 months as
carriers respectively). Under stress these
animals release the virus.

23. Differential diagnosis
i. Mucosal disease: (Lesion in buccal cavity,
conjunctivitis, diarrhoea and dysentery.)
ii.Rinderpest: (Lacrimation, discrete lesions (not
vesicles), diarrhoea and dysentery.)
iii.Malignant Catarrhal Fever: (Necrotic lesions, nasal
discharge, CNS signs & diarrhea)
iv.Vesicular stomatitis: (Affect also horses, confirmed
in laboratory)
v.Swine vesicular disease: (In swine very short, mild
with animals recovering quickly)
vi.Vesicular Exanthema: (In swine: very short, mild
with animals recovering quickly)

24. Diagnosis
• History of previous outbreaks within or
nearby to the farm, uncontrolled animal
movements, conflicts, contact with wild
ungulates, etc.
• Epidemiology: High morbidity, low
mortality, seasonality, species affected
• Clinical signs: Profuse salivation, smacking
of lips, severe lameness, recumbence sudden
death of calves

25. Laboratory diagnosis (High security
Lab)
•Serological tests such as Complement
Fixation Test (CFT), Serum Neutralizing
Test and ELISA.
For confirmation samples are;
•Blood in plain test tubes to allow
clotting
•Saliva diluted with PBS to lower pH
•Pieces of the skin that overlay the
blisters

26. •Vesicular fluid if this is available.
•Add PBS pH 7.4 to prevent desiccation
•Store at 4oC to reach the lab within 12
hrs
•Animal inoculation: Intradermal injection
of fresh vesicular fluid into the plantar
pads of the guinea pigs. Vesicles appear on
pads in 1 – 7 days and in the mouth 1 – 2
days later.

27. Treatment
•There is no specific treatment for this
disease but there is symptomatic treatment
to prevent secondary infections by using:
•Mild disinfectant locally on inflamed
areas eg. Chloride salt.
•Use of broad spectrum antibiotics
eg. Pen streptomycin.

28. Control
i. Quarantine: Restrict movement of animals and by products
in and out of the area.
ii. Slaughtering policy: Slaughter all affected animals and
compensate the farmers (not applicable in developing
countries).
iii. Vaccination: vaccine types depend on the serotype
•Vaccinate all animals around the outbreak (ring or barrier
vaccination)
• Annual vaccination in endemic areas: vaccination can be done
once, twice or three times per year depending on the challenge.
NB: Immunity lasts for 4 – 6 months and sometimes up to 1
year.
iv. Treat animal products: Example, pasteurelization of milk.

29. v. Biosecurity measures
• Standardize animal movements and keep to
an absolute minimum.
• People and Vehicles are a potential source of
potential contamination.
• Only allow essential visitors on to the farm
and provide your own boots and clothing at
the entrance.
• If visitors do not shower ensure hands are
washed.
• Limit the movement of people between
buildings as much as possible.

30. Economic importance
•FMD is the most important restraint to
international trade in animals and
animal products.
•Consequently, large sums of money
have been invested in control and
eradication programs
•Produces severe disease in pigs and
cattle
•Highly infectious

31. •Spreads rapidly throughout animal
populations and over long distances on
the wind and hence it is difficult and
costly to control.
•Its damaging and debilitating effect on
cattle
•Loss of productivity (milk, weight gains)
•Calf crop losses due to mortality and
abortions

32. •Interfere with livelihood in animal
dependent pastoral societies
•Preparation of vaccines (escape,
improper inactivation)
•Infertility in bulls
•Premature culling of animals

33. MALIGNANT CATARRHAL FEVER
(MCF)
(SYNONYMS: NOSE SICKNESS)
• Acute, sporadic but highly fatal infectious
disease of cattle characterized by a high and
persistent fever, ocular-nasal discharge,
keratoconjunctivitis, corneal opacity, erosive
stomatitis and gastroenteritis, erosions in the
upper respiratory tract and generalized
lymphadenopathy.
Etiology
• Herpes virus – 1

34. Epidemiology
Distribution : World wide but mostly in Africa
Incidence : Is sporadic, few animals are
affected
- Occasionally high morbidity incidents
have arisen in parts of Africa
- In Tanzania, MCF is a threat to livestock
during the wildebeest calving season
Hosts : Cattle highly susceptible
- African buffalo and water buffalo fairly
susceptible
- sheep and goats suffer apparently

35. • The disease affects cattle and buffaloes, while
wildebeest, goats and sheep are carriers by
contaminating the environment especially
during calving.
• Outbreak occurs in warmer months particularly
when the wildebeests are calving and are in
contact with cattle.
• Morbidity is 1 - 3% while mortality is 90 – 100
%.
Transmission : By direct contact
- The virus is present in the nasal and
ocular secretions where the rate of
contaminating the environment is high,
- The virus does not live long in the
normal air

36. CLINICAL SIGNS
The incubation period varies, 3 - 7 weeks
(average 3 weeks)
i. Affected animals have anorexia and
extremely dull.
ii. High and persistent temperature (41.50C)
iii. Profuse mucopurulent nasal discharge
(bilateral)
iv. Ocular discharge with variable degree of
edema of the eyelids, blepharospasms and
congestion of capillaries
v. Necrotic areas in the nasal cavity and on
buccal mucosa, hard palate, gum and
gingivae

37. vi. Salivation (excessive) with saliva hanging
vii.Necrotic lesions may occur at the skin -
horn junction, the teats, vulva and scrotum,
and in acute cases the skin may slough off
entirely on touching.
viii.Nervous signs: weakness in one leg,
incoordination, head pressing (pushing),
paralysis and convulsion at final stage
ix. Lymphadenitis
x. Diarrhoea and dysentery
xi. Opacity of the cornea: commencing as a
narrow, gray ring at peripheral spreading
centripetally.

38. Corneal opacity, lacrimation and nasal discharge

39. Erosive stomatitis Mucopurulant nasal discharge

40. POSTMORTEM LESIONS
i)Erosive lesions in the mouth, nasal
cavity, pharynx, alimentary tract,
urinary bladder, kidney and eyes
ii)All lymph nodes are swollen,
edematous and often haemorrhagic
iii)Petechial haemorrhages as well as
congestion in brain and meninges
iv)Dermatitis

41. Diagnosis
i. Epidemiology
ii. Clinical signs
iii. Pm lesions
iv. Serological tests: Virus
Neutralization tests (Wildebeests), CFT

42. TREATMENT
o No effective treatment
o Prevent secondary infection by antibiotics
CONTROL
i. Keep away cattle and buffaloes from carrier
animals
ii.Isolate the affected animals from the herd
• No effective vaccine is available to date.

43. RIFT VALLEY FEVER
(Synonymous: Enzootic hepatitis)
• This is an acute febrile disease of
ruminants and man characterized in
young animals by fever, hepatitis, and
death and in pregnant animals by
abortion and in man by an influenza-like
disease.
Aetiology
• Phlebovirus, family Bunyaviridae

44. Epidemilogy
• Distribution : In Africa, Saudi Arabia and
Yemen
• Susceptibility : Sheep, Cattle, Camels,
Domestic buffalo, Monkey, Man and Rats
are highly susceptible and Goats
moderately, but Pigs, Rabbits and Poultry
are not.
• Transmission : In ruminants and camels
by Mosquito (Aedes) and in man is by
contact with affected animals or through
handling of infected tissues.
• Incidence : Is high during heavy rainfall

45. Clinical signs
Sheep and Goats
• Incubation period: less than 3 days
- High rate of abortion (5-100%)
• Any stage of gestation, autolysed
fetus
- Asymptomatic
- Foul diarrhea, icterus, mucopurulent
nasal discharge
- Acute death (20-30%)

46. Lambs and Kids
Incubation period: 12-36 hrs
• Newborn deaths
- High fever, listless, anorexia
- Death - 12 hours to 2 days
- Less than 1 week old
• Mortality >90%
• Lambs and kids over 2 weeks old
• Mortality over 20%

47. Cattle
• Adults
- Fever, weakness, anorexia, ptyalism,
fetid diarrhea, icterus
- Death - Mortality 10%
- Abortion can be up to 100%
• Calves
- Similar signs to lambs and kids
- Mortality 10-70%

48. Post mortem findings
• Hepatic necrosis
- Liver enlarged,
yellow, friable
- Petechial
hemorrhages
prominent
• Cutaneous
• Serosal

49. Diagnosis
•Epidemiology.
•Clinical signs.
•Pm picture.
•Serological test: ELISA, CFT.

50. Differential diagnosis
i. Bluetongue (Due to abortion in enzootic
areas): But there is high mortality rate.
ii. Ephemeral fever: Muscle stiffness.
iii. Enterotoxaemia: culture of intestinal
contents, epidemiology –adult, young –
diarrhea.
• But Rift valley Fever has characteristics
hepatic lesions.

51. Treatment and control
Treatment ; No treatment
Control
- Annual vaccination of susceptible
animals
- Avoid and control vectors
- Personal protective equipment
• Aborted fetuses, necropsy
- Avoid contact with infected tissues and
blood
- Restrict movement of animals

52. MUCOSAL DISEASE
• This is acute or sub acute or chronic disease
of cattle characterized by fever, diarrhoea,
erosion of gastro – intestinal tract, abortion
and CNS involvements.
Aetiology
• Pestivirus (Family Togaviridae)
• The same virus causes two distinct
diseases: Mucosal disease (fatal disease)
and Bovine Viral Diarrhoea

53. Epidemiology
• Distribution: World wide
• Hosts : Cattle and buffaloes
• Immature animals (4 – 8 months) are mostly
affected by the mucosal disease.
• Transmission:
i. Direct transmission (Through contact)
ii. Indirect transmission (Formates;
arthropods)
iii. Vertical transmission (from dam to offspring)

54. Clinical signs
The incubation period is 1 – 3 weeks
(approximately 10 days)
i. Rise in temperature 42.5oC
ii.Dullness
iii.Inappetence due to lesions in buccal
cavity
iv.Nasal discharge; early stage is serous
(watery) late on becomes mucopurulent
and copious in nature
v.Superficial erosive lesions occur in the
nasal cavity, but no vesicles

55. vi. Halitosis
vii. Salivation (profuse)
viii.Conjunctivitis and lacrimation
ix. Diarrhoea and dysentery but not as in
Rinderpest
x. Dehydration and emaciation
xi. Pneumonia (coughing)
xii. Lesions on interdigital space, lameness
xiii.Abortion or give birth to abnormal
calves with CNS disorders: Cerebellar
hypoplasia, Cerebellar-ocular agenesis,
ocular defects etc

56. Differential diagnosis
i. Malignant Catarrhal Fever:
Presence of opacity in MCF
ii.FMD: Presence of Vesicles in FMD
iii.Johnes Disease: Diarrhoea without
lesion in Johnes disease
iv.Rinderpest: High morbidity and
Mortality rates, no coughing and
CNS signs.

57. Diagnosis
i. Epidemiology: Morbidity, mortality and
age factor
ii. Clinical signs
iii. Serological test : CFT, ELISA and Gel
diffusion precipitation (GDP)

58. Treatment and control
Treatment:
• There is no specific treatment; the prognosis
for severe cases is unfavorable
Control:
• No proper control measure is recommended
• Animals with chronic disease should be
culled and destroyed

59. EPHEMERAL FEVER
(Synonymous: Three days
sickness)
• This is arthropod – transmitted disease of
cattle and buffaloes characterized by
transitory fever, lymphadenitis, watery
nasal discharge and myositis, which come
in and subside within a few days (mostly 3
days).
Aetiology
• The disease is caused by Virus called
Rhabdovirus

60. Epidemiology
• Occurrence: in low-lying areas, damp
areas, near river or at the onset of rain
season.
• Host: Commonly in cattle and Buffaloes
• Bulls and heavy cattle are the most severely
affected animals.
• Transmission:
- Insects are responsible for transmission
eg. Culicoides and mosquitoes.
- However, the disease may occur in areas
where insects are not found.

61. Clinical signs
i. Biphasic fever and shivering
ii. In appetence (anorexia)
iii. Lacrimation
iv. Watery (serous) nasal discharge
v. Dyspnoea

62. vi. Atony of fore stomach
vii. Depression
viii.Stiffness and sometimes lameness
(due to myositis)
ix. Affected animals may become
recumbent from 8 hours to more than a
week
x. Drop in milk production and abortion
may occur

63. Diagnosis
• Clinical signs
• Serological tests
• Isolation of virus

64. Treatment
• Complete rest is the most effective
treatment
• Anti inflammatory drug if given early
are helpful
• Antibiotic to control secondary
infection
• Calcium borogluconate can be given to
recumbent animals.