Epidemiology of Tularemia

Abstract

Tularemia is considered to haveexisted in Anatolia forseveral thou-sandyears. There aresuspicions regarding itsusein biological war-farein theNeshite-Arzawan conflict. Thecausative agent of tularemia mayhavefirstbeenusedasa biological weapon in 1320-1318 BC. Thedisease hasrecently become a significant re-emerging disease globally as wellas in Turkey. In theperiod of 2001-2010, Kosovo had thehighest annual incidence in Europe at a rateof5.2per100,000. Sweden, Finland, Slovakia, Czech Republic, Norway, Serbia-Mon-tenegro, Hungary, Bulgaria, andCroatia follow withrates of2.80, 1.19, 1.0,0.81, 0.42, 0.4,0.36, 0.21, and0.15per100,000 people, respectively. Tularemia inTurkey wasfirstreported inthesoldiers living in theregion veryclose to theKaynarca Stream ofThrace in 1936. It hasstarted to gainmore andmore importance, especially in recent decades in Turkey, dueto a veryhighnumber of cases andits spread throughout thecountry. A totalof 431tularemia cases werere-corded in Turkey in 2005, buta significant reduction wasobserved in thenumber of thecases in thenextthreeyears; thenumber of patients decreased to 71in 2008. Thenumber of cases increased again in 2009 andcontinued in subsequent years. Thenumber of cases reached 428, 1531, 2151, and607in 2009, 2010, 2011, and2012, respectively. The number ofcases peaked in2011 inTurkey, andwasinfacthigher thanthetotalnumber ofcases in allEuropean Union countries. The number of cases is higher in females thanmales in Turkey. In Turkey, 52%of cases of tularemia diagnoses occur fromDecember to March andthemostcommon clinical presentation is theoropharyngeal form caused bycontaminated water. Rodents arethemostlikely sources of tularemia outbreaks in Turkey as wellas in Kosovo. Organisms such as ticks, fliesandmosquitoes arevectors of tularemia transmission to mammals. Because tickscancarry thebacteria bybothtransovarial andtransstadial transmission, theyplaya roleinthelifecycle of tularemia as both reservoir and vector.