تشخيصات

1. ETIO LOGY
Foot-and -mouth disease is
associated
with an aphthovirus (family
Piconaviridae)
which occurs as seven major
serotypes: A,
0, C, Southern African Territories
(SAT) 1,
SAT 2, SAT 3 and Asia 1.

2. • No cross-immunity between serotypes
• great changes in antigenicity between developing serotypes;
virulence may also change dramatically.
• EPIDEMIOLOGY
• Occurrence : FMD affects all cloven-footed animals and is endemic in
Africa, Asia, South America and parts of Europe. The disease
generally occurs in the form of an outbreak that rapidly spreads from
herd to herd before it is controlled. Morbidity and case-fatality rate :
100% , 2% adult , 20% young stock.
• Methods of transmission : inhalation or by ingestion , contact
between Animals , airborne ,
• In cattle, the first site of virus infection and subsequent rapid
multiplication is the pharynx. Following a few days of viremia, virus
appears in milk and saliva for up to 24 h before vesicles appear in the
mouth. All other excretions including urine, feces and semen may be
similarly infective before the animal is clinically ill and for a short
period after signs have disappeared.
• Carriers.

3. Occurrence of the disease :
• Endemic : infection or disease which are indigenous or normally present
among the population of the area .
• Epidemic : infection or disease which occurs occasionally and excess of
normal expectancy in the population of the area .
• Pandemic : Very wide spread disease which may be world wide in
distribution .
• Sporadic : disease which appeared rarely or occasionally in individual of
population .
• Prevalence : amount of disease is a known population at particular time .
• Incidence : number of new cases that occurred in a known population over
a period of time .

4. Pathogenesis
• Inhalation/ingestion oropharyngeal
infection viremiaepidermal cells signs
and lesions enhanced by mechanical trauma
Clinical signs Fever, profuse salivation,
vesicles in mouth and feet, sudden death in
young animal

5. PATHOGENESIS
• Virus particles first attach to mucosal epithelial cells, penetrate into
the cytoplasm and replicate until the cells disintegrate. This releases
more viral particles to infect other cells, including macrophages which
drain into the efferent lymphatic system and then the blood. once
infection gains access to the bloodstream, the virus is widely
disseminated to many epidermal sites, probably in macrophages, but
gross lesions develop only in areas subjected to mechanical trauma or
unusual physiological conditions such as the epithelium of the mouth
, feet, and teats. Characteristic lesions develop at these sites after an
incubation period of 1-21 d (usually 3-8 d in most species) . The initial
phase of viremia is often unnoticed and it is only when localization in
the mouth and on the feet occurs that the animal is found to be
clinically abnormal.
• Bacterial complications. feet and the teats - lameness
• and mastitis.
• Young animals, especially neonates, the virus frequently causes
necrotizing myocarditis.

6. CLINICAL FINDINGS
• fall in milk yield and.
• high fever (40-41C.
• severe dejection and anorexia.
• Acute painful stomatitis.
• salivation, the saliva hanging in long, ropy strings, a characteristic
smacking of the lips, Vesicles and bullae. Rupture within 24 h, leaving
a raw painful surface.
• vesicles appear on the feet, particularly in the clefts and on the
coronet.
• Pregnant animals may abort or have stillbirths.
• Occasional cases show localization in the alimentary tract with
dysentery or diarrhea, indicating the presence of enteritis.

7. CLIN ICAL PATHOLOGY
• 1. Identification of the agent in tissue or fluid :
• Virus isolation.
• ELISA.
• CFT.
• RT-PCR.
• 2. Serological tests for specific antibody response to FMD structural or
nonstructural proteins:
• Virus neutralization (VN),and ELISA .
• 3. Experimental transmission.

8. DIFFERENTIAL DIAGNOSIS
• Vesicular stomatitis in cattle.
• Bluetongue of sheep.
• Bovine viral diarrhea/mucosal disease,rinderpest, malignant
catarrhal fever and lumpy skin disease.NO vesicular
( superficial erosion then develop to ulcer ) .
• Pox infections of the mammary gland and foot rot in sheep.
• Ingestion of any caustic material may cause oral vesiculation
and salivation.