Middle East DVEP - Armed Forces Pest Management Board

and sheep, although immature stages may occasionally feed on hedgehogs, rodents andhares.Each tick instar requires a bloodmeal prior to maturing to the next stage. After feeding,females drop from the host and oviposit. Rhipicephalines lay hundreds of eggs, generallyin the dens of host animals, especially canines. In the genus Hyalomma, the number ofeggs laid is variable, ranging from hundreds in rodent burrows to thousands on openground or vegetation. Eggs usually hatch within 30 days. Adult Rhipicephalus arepassive in their host-questing activity (rarely moving more than 2 m), while Hyalommaare quite aggressive and move considerable distances to find a host. However, immatureticks of most species are more active and climb vegetation or other objects in order toquest for hosts. Hyalomma rufipes is among the world’s hardiest ticks and can easilysurvive extremes of heat, cold and aridity. Over the centuries, this species has beendistributed along caravan trade and cattle drive routes. During migration, birds play arole in distributing H. rufipes. Amblyomma variegatum is an introduced species thatprobably thrives only in areas where there is adequate rainfall, particularly in themountains of southwestern Saudi Arabia (Asir District) and Yemen. The same situationwould apply for R. appendiculatus, which also requires a humid environment. Similarly,R. sanguineus and R. turanicus require humid microhabitats, which favor a distribution intemperate areas.Vector Surveillance and Suppression. Personal protective measures discussed inTIM 36 afford the best protection against boutonneuse fever. Thirty percent of dogsrandomly sampled in Israel, and 82 to 84% of the dogs belonging to two communities inwhich outbreaks of human spotted fever had occurred, were positive for R. conorii. Mostdogs surveyed in Israel were heavily infested with vector ticks, and people who kept dogshad a higher incidence of boutonneuse fever. Troops should not be allowed to feed,befriend or adopt local dogs as pets.I. Tick-borne Encephalitis (TBE).TBE, caused by a complex of flaviviruses, actually comprises two clinically differentdiseases, Far Eastern TBE, also known as Russian spring-summer encephalitis, andCentral European TBE, also known as biphasic meningoencephalitis, or diphasic milkdisease. Human disease of the Far Eastern subtype is usually clinically more severe inthe acute phase and is associated with a higher rate of chronic nervous system sequelaethan the Central European subtype. The term TBE is used to identify the broad spectrumof clinical syndromes caused by the virus, ranging from a simple febrile illness to severecentral nervous system infection that may be fatal. However, most serologicallydocumented infections are inapparent. The incubation period ranges from 7 to 14 days.Military Impact and Historical Perspective. Illness of the Far Eastern subtype wasfirst described in 1937 during an epidemic in the Russian Far East. The European subtypewas clinically defined in 1948 during an epidemic in Central Bohemia. TBE virus existsin discrete foci. It would have minimal impact on military operations, although militarypersonnel might experience a high level of exposure to vector ticks.90