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 time6-Incidence : number of new cases that occurred in a known population over a period of time .

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 animalPATHOGENESIS: 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.

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.