Middle East DVEP - Armed Forces Pest Management Board

VIII. Noxious/Venomous Animals and Plants of Military Significance.A. Arthropods.Annoyance by biting and stinging arthropods can adversely affect troop morale. Thesalivary secretions and venoms of arthropods are complex mixtures of proteins and othersubstances that are allergenic. Reactions to arthropod bites and stings range from mildlocal irritation to systemic reactions causing considerable morbidity, including rare butlife-threatening anaphylactic shock. Insect bites can be so severe and pervasive that theyaffect the operational readiness of troops in the field. Their discomfort alone has been amajor complaint by soldiers deployed in many regions of the world. The followinggroups of noxious arthropods are those most likely to be encountered by militarypersonnel operating in countries of the Middle East.1. Acari (ticks and mites). Tick paralysis is a potentially fatal but easily cured afflictionof man and animals. It is almost exclusively associated with hard (ixodid) ticks and iscaused by injection of a neurotoxin(s) in tick saliva. Worldwide, nearly 50 species of hardticks have been associated with tick paralysis, although any ixodid may be capable ofproducing this syndrome. A tick must be attached to its host for 4 to 6 days beforesymptoms appear. This condition is characterized by an ascending, flaccid paralysis,usually beginning in the legs. Progressive paralysis can lead to respiratory failure anddeath. Diagnosis simply involves finding the embedded tick, usually at the base of theneck or in the scalp. After tick removal, symptoms resolve within hours or days.However, if paralysis is advanced, recovery can take several weeks. No drugs areavailable for treatment. Several species of ticks known to cause tick paralysis arewidespread in the Middle East, including Hyalomma truncatum, Haemaphysalis punctata,Dermacentor marginatus, and Ixodes ricinus.Most tick bites are painless, produce only mild local reaction, and frequently gounnoticed. However, inflammation or even hypersensitivity reactions may occur within afew days of tick attachment. After tick removal, a reddened nodule may persist for weeksor months. The bite of the cave tick, Ornithodoros tholozani, produces deep red, crustednodules or papules up to 1.5 cm in diameter. Tick toxicosis is a systemic reaction to ticksaliva. In Israel, Ixodes redikorzevi causes human toxicosis characterized by swelling atthe point of attachment, regional lymph adenopathy and, sometimes, fever. Thesymptoms disappear 1 to 2 days after removal of the tick. Tickbite anaphylaxis has rarelybeen reported, but studies in Australia suggest it is more common and potentially lifethreatening than tick paralysis.Sarcoptes scabiei (family Sarcoptidae) are parasitic mites that spend their entire life cyclein burrows in the skin of mammals. Mite infestations cause scabies in man and mange inother animals, including primates, horses, wild and domestic ruminants, pigs, camels,rabbits, dogs and other carnivores. Sarcoptes scabiei is considered one species.Populations found on different host species differ physiologically more thanmorphologically and are referred to as forms (that on man, for instance, is S. scabiei formhominis). Those from one host species do not establish themselves on another. Humanscan become infested from horses or dogs, but such infestations are mild and disappearwithout treatment.132