Title: Human dirofilariasis due to Dirofilaria repens in the Russian Federation—remarks concerning epidemiology
Abstract: A valuable contribution to the knowledge on Dirofilaria repens dirofilariasis in the Russian Federation was recently published.1Ermakova LA, Nagorny SA, Krivorotova EY, Pshenichnaya NY, Matina ON. Dirofilaria repens in the Russian Federation: current epidemiology, diagnosis, and treatment from a federal reference center perspective. Int J Infect Dis 2014; 23:47–52. http://dx.doi.org/10.1016/j.ijid.2014.02.008 [Epub ahead of print].Google Scholar However, the epidemiological part of the manuscript requires some comments. The authors compared the number of human dirofilariasis cases described up to 2011 in Russia to the number of human D. repens infections described worldwide up to 2000 – 701 and 782 cases, respectively.2Sergiev V.P. Supryaga V.G. Darchenkova N.N. Zhukova L.A. Ivanova T.N. [Dirofilariosis of human in Russia] (in Russian).Rossijskij Parazitologičeskij Žurnal. 2012; 4: 60-64Google Scholar, 3Pampiglione S. Rivasi F. Human dirofilariasis due to Dirofilaria (Nochtiella) repens: an update of world literature from 1995 to 2000.Parassitologia. 2000; 42: 231-254PubMed Google Scholar Such a comparison is confusing. Only 69 of 782 described cases originated from Russia in the review cited by the authors.3Pampiglione S. Rivasi F. Human dirofilariasis due to Dirofilaria (Nochtiella) repens: an update of world literature from 1995 to 2000.Parassitologia. 2000; 42: 231-254PubMed Google Scholar These data were indirectly confirmed by Russian sources. Between 1915 and 2001, 264 cases of human dirofilariasis were recorded in Russia, however, almost half of those cases (43%) occurred during the last 3 years of the period analyzed (1999–2001).4Avdiukhina T.I. Postnova V.F. Abrosimova L.M. Kovtunov A.I. Arakel'ian S.E. Murashov N.E. et al.[Dirofilariasis (D. repens) in the Russian Federation and some of the Commonwealth of Independent States countries: situation and trends] (in Russian).Med Parazitol (Mosk). 2003; : 44-48PubMed Google Scholar The accuracy in choosing the time frame for comparison is of great importance because at the turn of the 21st century, a dramatic increase in the number of reported human dirofilariasis cases was recorded in central and eastern Europe,5Simón F. Siles-Lucas M. Morchón R. González-Miguel J. Mellado I. Carretón E. et al.Human and animal dirofilariasis: the emergence of a zoonotic mosaic.Clin Microbiol Rev. 2012; 25: 507-544https://doi.org/10.1128/CMR.00012-12Crossref PubMed Scopus (476) Google Scholar, 6Cielecka D. Żarnowska-Prymek H. Masny A. Salamatin R. Wesołowska M. Gołąb E. Human dirofilariosis in Poland: the first cases of autochthonous infections with Dirofilaria repens.Ann Agric Environ Med. 2012; 19: 445-450PubMed Google Scholar, 7Masny A. Gołąb E. Cielecka D. Sałamatin R. Vector-borne helminths of dogs and humans—focus on central and eastern parts of Europe.Parasit Vectors. 2013; 6: 38https://doi.org/10.1186/1756-3305-6-38Crossref PubMed Scopus (15) Google Scholar including Russia8Kartashev V. Batashova I. Kartashov S. Ermakov A. Mironova A. Kuleshova Yu et al.Canine and human dirofilariosis in the Rostov region (southern Russia).Vet Med Int. 2011; 2011: 685713https://doi.org/10.4061/2011/685713Crossref PubMed Scopus (37) Google Scholar. For example, in Ukraine, 1465 new cases were reported between 1997 and 2012.9Sałamatin R.V. Pavlikovska T.M. Sagach O.S. Nikolayenko S.M. Kornyushin V.V. Kharchenko V.O. et al.Human dirofilariasis due to Dirofilaria repens in Ukraine, an emergent zoonosis: epidemiological report of 1465 cases.Acta Parasitol. 2012; 58: 592-598https://doi.org/10.2478/s11686-013-0187-xCrossref Scopus (73) Google Scholar Interestingly, the border between Russia and Ukraine divides the regions with the highest numbers of detected human D. repens infections in both countries.10Darchenkova N.N. Supriaga V.G. Guzeeva M.V. Morozov E.N. Zhukova L.A. Sergiev V.P. [Prevalence of human dirofilariasis in Russia].Med Parazitol (Mosk). 2009; : 3-7PubMed Google Scholar Therefore, in our opinion, in the analysis of the epidemiological situation of dirofilariasis in Russia, it would be important to consider the epidemiological data from Ukraine in order to get a better understanding of the problem. The authors' hypothesis, presented also as a conclusion, was that the trained Russian police and armed forces dogs might serve as epidemiologically important 'amplifiers' of dirofilariasis in the former Soviet Union countries. Unless more of the dogs were exported abroad to Ukraine than sent to the various regions within Russia, the two-fold higher number of cases of human dirofilariasis in Ukraine compared to Russia would suggest that factors other than the trained Russian dogs contributed predominantly to the changes in epidemiological situation in the former Soviet Union countries. Funding: None. Conflict of interest: None declared.