Epidemiology of Tularemia

Tularemia is considered to have existed in Anatolia for several thousand years. There are suspicions regarding its use in biological warfare in the Neshite-Arzawan conflict. The causative agent of tularemia may have first been used as a biological weapon in 1320-1318 BC. The disease has recently become a significant re-emerging disease globally as well as in Turkey. In the period of 2001-2010, Kosovo had the highest annual incidence in Europe at a rate of 5.2 per 100,000. Sweden, Finland, Slovakia, Czech Republic, Norway, Serbia-Montenegro, Hungary, Bulgaria, and Croatia follow with rates of 2.80, 1.19, 1.0, 0.81, 0.42, 0.4, 0.36, 0.21, and 0.15 per 100,000 people, respectively. Tularemia in Turkey was first reported in the soldiers living in the region very close to the Kaynarca Stream of Thrace in 1936. It has started to gain more and more importance, especially in recent decades in Turkey, due to a very high number of cases and its spread throughout the country. A total of 431 tularemia cases were recorded in Turkey in 2005, but a significant reduction was observed in the number of the cases in the next three years; the number of patients decreased to 71 in 2008. The number of cases increased again in 2009 and continued in subsequent years. The number of cases reached 428, 1531, 2151, and 607 in 2009, 2010, 2011, and 2012, respectively. The number of cases peaked in 2011 in Turkey, and was in fact higher than the total number of cases in all European Union countries. The number of cases is higher in females than males in Turkey. In Turkey, 52% of cases of tularemia diagnoses occur from December to March and the most common clinical presentation is the oropharyngeal form caused by contaminated water. Rodents are the most likely sources of tularemia outbreaks in Turkey as well as in Kosovo. Organisms such as ticks, flies and mosquitoes are vectors of tularemia transmission to mammals. Because ticks can carry the bacteria by both transovarial and transstadial transmission, they play a role in the life cycle of tularemia as both reservoir and vector.