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→Vectors
===Vectors===
===Vectors===
The arthropd vector for bluetongue virus is the ''Culicoides'' biting midge. These insects breed in damp soil enriched with dung and take blood meals from vertebrate hosts.
The arthropd vector for bluetongue virus is the ''Culicoides'' biting midge. These insects take blood meals from vertebrate host and breed in damp, dung-enriched soil enriched, and so are abdunant in the vicinity of domestic livestock. The activity of ''Culicoides'' varies with the time of day: the midges are most active at night, from an hour before sunset to an hour after sunrise. Activity is decreased by windy conditions, and increased during the day when the weather is dull. ''Culicoides'' generally avoid entering buildings and other closed spaces.
3.2 Culicoides species have a normal insect complete metamorphosis life cycle –
3.2 Culicoides species have a normal insect complete metamorphosis life cycle –
egg, four larval instars, pupa and adult. In temperate and cool regions they
egg, four larval instars, pupa and adult. In temperate and cool regions they
Britain. The life span of adults is usually about 10 days, but in cooler conditions their
Britain. The life span of adults is usually about 10 days, but in cooler conditions their
metabolism slows and they may survive for periods of more than a month.
metabolism slows and they may survive for periods of more than a month.
Most species require a blood meal before laying eggs, although C. impunctatus (the
Most species require a blood meal before laying eggs, although C. impunctatus (the
Scottish highland biting midge), a member of the C. pulicaris group, does not require a
Scottish highland biting midge), a member of the C. pulicaris group, does not require a
efforts have not been made to collect rather than the species is absent there. Generally,
efforts have not been made to collect rather than the species is absent there. Generally,
the insects congregate where there are breeding sites and hosts upon which to feed.
the insects congregate where there are breeding sites and hosts upon which to feed.
Thus, the highest concentrations of C. obsoletus and/or C. pulicaris group midges are
Thus, the highest concentrations of C. obsoletus and/or C. pulicaris group midges are
found where cattle, horses, pigs and, to a lesser extent, sheep populations are highest.
found where cattle, horses, pigs and, to a lesser extent, sheep populations are highest.