Middle East DVEP - Armed Forces Pest Management Board

mortality in calves and lambs and abortion in nearly all pregnant livestock. In humans,RVF virus normally causes an acute, undifferentiated, febrile disease. Severe sequelae,including encephalitis and hemorrhagic fever, may occur. RVF virus was restricted tosub-Saharan Africa until a 1977 epidemic in Egypt, which involved an estimated 18,000human cases. The principal vectors during the epidemic were members of the Cx. pipienscomplex. Other competent vector species that are widespread in the Middle East includeAe. caspius, Anopheles pharoensis, Cx. perexiguus and Cx. antennatus. Therefore,countries in this region may be vulnerable to the introduction of RVF virus. Increasinghuman traffic across the Sinai, as well as the smuggling of unvaccinated domesticanimals, will pose a continuing threat of introduction of RVF virus into Israel.VI. Militarily Important Vector-borne Diseases with Long Incubation Periods (>15days)A. Leishmaniasis. This potentially disfiguring and sometimes fatal disease is causedby infection with protozoan parasites of the genus Leishmania. Transmission resultsfrom bites of infected phlebotomine sand flies. All vectors of leishmaniasis in the OldWorld are in the sand fly genus Phlebotomus. Incubation in humans may take as little asten days, or more than six months. Symptoms include ulcerative cutaneous lesions(cutaneous leishmaniasis or CL), lesions in the mucosal areas of the mouth and/or nose(mucocutaneous leishmaniasis or MCL), and internal pathological manifestationsresulting in fever, swollen lymph glands, anemia, enlargement of the liver and spleen,and progressive emaciation and weakness (visceral leishmaniasis or VL). In the MiddleEast, both CL and VL are important public health problems.CL (Baghdad boil, Jericho boil, Oriental sore), caused by infection with Leishmaniamajor or Le. tropica, typically appears as a nonhealing ulcer. The lesion usuallydevelops within weeks or months after a sand fly bite and slowly evolves from a papuleto a nodule to an ulcer. Cutaneous lesions may resolve quickly (2-3 months) withouttreatment or they may become chronic (lasting months to years) and will seldom healwithout treatment. Scarring is associated with healing. In endemic areas, such scars arecommon among both rural and urban populations. Life-long immunity to the infectingLeishmania species normally results.VL (Kala-azar, Dum Dum fever), is the most severe form of leishmaniasis, with as muchas 95% mortality in untreated cases. It is a chronic disease and, without treatment, ismarked by fever (2 daily peaks), weakness and, as the parasites invade internal organs,weight loss coupled with enlargement of spleen and liver that may resemble severemalnutrition. It should be noted that cutaneous lesions may also be seen in humanvisceral leishmaniasis cases, but the chronic visceralizing nature of the disease is themain concern. In the Old World, VL is usually attributed to L. donovani or L. infantum.Viscerotropic L. tropica has also been reported and was described in veterans of thePersian Gulf war. The incubation period for VL is usually 4 to 6 months but may be asshort as 10 days or as long as two years. By the time the disease is diagnosed, patientshave usually forgotten any contact with sand flies. In endemic regions it is a disease ofthe young and old, who succumb to it disproportionately. Epidemics of VL often followconditions of severe drought, famine or disruption of native populations by wars that107