Emerging Natural Focal Infectious Diseases in Russia: A Medical–Geographical Study

Abstract

In Russia, as in other countries, the problem of emerging natural focal infectious diseases (EIDs) became more acute toward the end of the 20th century. However, the situation in Russia is unknown to foreign readers, while the prevention and control of these diseases require international collaboration. The aim of the study is to provide a medical–geographical assessment of the distribution of the main natural focal EIDs in Russia, as well as to present the approaches used in the country to create aggregate maps of risk assessment. To consider its current status, we determined the most important natural focal EIDs for Russia (tick-borne encephalitis, ixodid tick-borne borrelioses, hemorrhagic fever with renal syndrome, Crimean–Congo hemorrhagic fever, West Nile fever, Astrakhan spotted fever, leptospiroses, and tularemia) and analyzed the patterns of their epidemic manifestation. As a result, a working classification of such infections and a series of maps showing the current situation of EID morbidity in Russia were created. To design an aggregated risk map, we developed an original mapping methodology and recalculated the model disease incidence by taking data from administrative units and adjusting them for natural geographical boundaries (biomes) for European Russia, and then evaluated the risk of infection for separate model diseases and for a set of them. The highest risk rates are confined to the northwest regions of European Russia, the Cis-Urals and the Volga region, which are naturally related to forest biomes, as well as to the southern steppe regions of the interfluves between the Volga and the Don, and the foothills of the North Caucasus.

Natural and Socioeconomic Conditions Influence Tick-Borne Encephalitis Cases in Russia

“…Tick-Borne Encephalitis (TBE) is a natural focal viral disease, which is mainly transmitted by Ixodes persulcatus and I. ricinus [1,2], can cause human long-term neurological sequelae, fever, and even general intoxication [3]. Tick-borne encephalitis viruses (TBEV) were first found in Russia Far East in 1937 [1], and the incidence and geographic range of TBE have increased in Europe over the past decades [3].…”

“…Human TBE incidences were also found in the northern boreal forests of Mongolia [4], and cluster infections in Northeast China [5] and other regions. However, globally, TBEV are chiefly distributed in Russia [2].…”

“…At the national scale, NDVI was proved to be positively correlated with tick survival [18] and nymphal ticks' abundance [19], and lead to a positive correlation with TBE incidence [20,21], but the effect of NDVI on tick activity varied from country to country, and some uncorrelated studies had also been observed [22]. As cities continued to expand to suburbs and ticks invaded urban parks and green spaces, cities had gradually become the new focus of TBE infection [2]. At the urban scale, increased NDVI in urban green space in late spring caused a decrease in TBE incidence [12].…”

“…Although there were studies building models to discuss how climate change led to human economic loss, our models focused on its influence on human health [28,29]. In Russia, existing studies had documented the temporal and spatial changes of TBE incidence, incidence rates differences in occupation and age, and climate and ecological factors affecting tick activity [1,2]. In terms of the risk factors, they only examined the effect of urban expansion on increased TBE incidence in children [1,2].…”

Associating Land Cover Changes with Patterns of Incidences of Climate-Sensitive Infections: An Example on Tick-Borne Diseases in the Nordic Area

“…In Fennoscandia and western Eurasia, there has been a clear extension into new areas of the distribution range of large mammals that carry ticks capable of transmitting infectious diseases to humans [12][13][14][15][16][17]. These changes in distribution range are associated with an increase in northern areas of several vector-borne zoonotic diseases [18,19].…”