"The estimated number of PWID in Russia was close to 2 million in 2008 (Mathers et al., 2008). 2.3% of the Russian population uses opioids annually and 1.4% heroin, compared to an annual prevalence of 0.4% opioid use in Western and Central Europe (UNODC, 2012). While actual epidemiological data is not available, a number of academic and media reports suggest that 5% or more of Russian drug users (approximately 100,000 PWID) may be injecting krokodil (Walker, 2011), while 'various official estimates' place the numbers of Russian PWID using krokodil as high as one million (Shuster, 2011). Epidemiological data is critical to evaluating claims that the use of krokodil is reaching epidemic proportions in Russia (Walker, 2011), and potentially, the Ukraine. There are an estimated 290,000 to 375,000 PWID in Ukraine (Mathers et al., 2008). A recent national survey found that 7% of PWID have used krokodil in 2011 (Balakireva, 2012), suggesting that around 20,000 PWID in Ukraine may have used krokodil that year. Balakireva and colleagues furthermore found statistically significant differences in krokodil use between the cities in the study, with most krokodil use reported in Uzhhorod (35.6%), Simferopol (26.9%), Kyiv (21.7%), Chernivtsi (15.5%) and Donetsk (12.6%). Estimates from other countries are not available. Outside of the former Soviet region, krokodil has been reported in Germany (Der Spiegel, 2011) and in Tromsø in northern Norway (Lindblad, 2012)."