Exhibit 8, 100416 Brazil FMD Risk Evaluation - R-Calf

ANNEXES
Annex 1. Hazard Identification: Foot-and-Mouth Disease Virus
Etiologic Agent
Family Picornaviridae, Genus Aphthovirus, types O, A, C, SAT1, SAT2, SAT3, and Asia 1.
Status in the United States
FMD virus was eradicated from the United States in 1929.
Epidemiology
FMD is a highly communicable disease of cloven-hoofed animals caused by an Aphthovirus of the
family Picornaviridae. FMD has seven immunologically distinct serotypes (O, A, C, SAT1, SAT2,
SAT3, and Asia 1). The O, A, and C serotypes have historically been found in South America [44].
Research indicates that one serotype does not confer protective immunity against the other six; thus
a disease outbreak can be caused by one serotype or a combination of serotypes [45].
FMD virus serotype O (PanAsia strain) has been isolated in over 60 percent of positive samples
received by the World Reference Laboratory for FMD in the United Kingdom (Institute for Animal
Health, Pirbright Laboratory). Along with being the most prevalent type O strain, the PanAsia strain
is also the most widely distributed, causing FMD outbreaks in many parts of Africa, Asia, and South
America as well as in Europe since 1998. This virus strain can infect a wide range of species
including cattle, water buffalo, pigs, sheep, goats, and gazelles.
FMD virus can be transmitted by direct or indirect contact or aerosol. Fomites (items such as feed,
drinking water, equipment, animal products, human clothing, transportation vehicles, rodents, stray
dogs, wild animals, and birds) can transmit FMD over long distances. The five main elements that
influence the extent of FMD spread are:
The quantity of virus released
The means by which the virus enters the environment
The ability of the virus to survive outside the animal body
The quantities of virus required to initiate infection at primary infection sites
The period of time the virus remains undetected [46, 47]
The incubation period of the FMD virus is 2 to 14 days in cattle, depending on the viral strain and
dose and the level of susceptibility of the animal [48]. Morbidity in unvaccinated herds can be high,
but mortality usually does not exceed 5 percent. If an outbreak occurs during the calving season,
calf mortality can be considerable [49]. Young calves may even die before clinical signs appear,
because the virus attacks the heart muscles [48].
The respiratory tract is the usual route of infection in species other than pigs. Infection can also
occur through abrasions of the skin or mucous membranes. In cattle and sheep, the earliest sites of
virus infection and possibly replication appear to be in the mucosa and the lymphoid tissues of the
pharynx. Following initial replication in the pharynx, the virus then enters the bloodstream.
Viremia in cattle lasts for 3 to 5 days; as a result, the virus spreads throughout the body and
establishes sites of secondary infection [50].
APHIS Evaluation of the Status of the Brazilian State of Santa Catarina 71