Foot-and-mouth disease is caused by an aphthovirus that has seven major serotypes. It affects cloven-hooved animals and is endemic in parts of Africa, Asia, South America, and Europe. The virus is transmitted through inhalation, ingestion, or contact between animals and infects the pharynx before spreading to other areas. This causes fever, vesicles in the mouth and on the feet, and can occasionally lead to sudden death in young animals.

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

2. Pathogenesis: Inhalation/ingestion ,oropharyngea linfection viremia
,epidermal cells , signs and lesions enhanced by mechanical trauma
Clinical signs Fever, profuse salivation, vesicles in mouth and feet,
sudden death in young animal
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.
CLINICAL FINDINGS:
-fall in milk yield and.
-high fever (40-41"C.
-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.

3. 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.
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.