Natural-focal diseases: mapping experience in Russia

Tick-Borne Encephalitis (TBE): From Tick to Pathology

Tick-borne encephalitis (TBE) is a viral arthropod infection, endemic to large parts of Europe and Asia, and is characterised by neurological involvement, which can range from mild to severe, and in 33-60% of cases, it leads to a post-encephalitis syndrome and long-term morbidity. While TBE virus, now identified as Orthoflavivirus encephalitidis, was originally isolated in 1937, the pathogenesis of TBE is not fully appreciated with the mode of transmission (blood, tick, alimentary), viral strain, host immune response, and age, likely helping to shape the disease phenotype that we explore in this review. Importantly, the incidence of TBE is increasing, and due to global warming, its epidemiology is evolving, with new foci of transmission reported across Europe and in the UK. As such, a better understanding of the symptomatology, diagnostics, treatment, and prevention of TBE is required to inform healthcare professionals going forward, which this review addresses in detail. To this end, the need for robust national surveillance data and randomised control trial data regarding the use of various antivirals (e.g., Galidesivir and 7-deaza-2'-CMA), monoclonal antibodies, and glucocorticoids is required to improve the management and outcomes of TBE.

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

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.

Review: The risk of contracting anthrax from spore-contaminated soil - A military medical perspective

Anthrax is an infectious disease of relevance for military forces. Although spores of Bacillus anthracis obiquitously occur in soil, reports on soil-borne transmission to humans are scarce. In this narrative review, the potential of soil-borne transmission of anthrax to humans is discussed based on pathogen-specific characteristics and reports on anthrax in the course of several centuries of warfare. In theory, anthrax foci can pose a potential risk of infection to animals and humans if sufficient amounts of virulent spores are present in the soil even after an extended period of time. In praxis, however, transmissions are usually due to contacts with animal products and reported events of soil-based transmissions are scarce. In the history of warfare, even in the trenches of World War I, reported anthrax cases due to soil-contaminated wounds are virtually absent. Both the perspectives and the experience of the Western hemisphere and of former Soviet Republics are presented. Based on the accessible data as provided in the review, the transmission risk of anthrax by infections of wounds due to spore-contaminated soil is considered as very low under the most circumstance. Active historic anthrax foci may, however, still pose a risk to the health of deployed soldiers.

How to Tackle Natural Focal Infections: From Risk Assessment to Vaccination Strategies

Natural focal diseases are caused by biological agents associated with specific landscapes. The natural focus of such diseases is defined as any natural ecosystem containing the pathogen's population as an essential component. In such context, the agent circulates independently on human presence, and humans may become accidentally infected through contact with vectors or reservoirs. Some viruses (i.e., tick-borne encephalitis and Congo-Crimean hemorrhagic fever virus) are paradigmatic examples of natural focal diseases. When environmental changes, increase of reservoir/vector populations, demographic pressure, and/or changes in human behavior occur, increased risk of exposure to the pathogen may lead to clusters of cases or even to larger outbreaks. Intervention is often not highly cost-effective, thus only a few examples of large-scale or even targeted vaccination campaigns are reported in the international literature. To develop intervention models, risk assessment through disease mapping is an essential component of the response against these neglected threats and key to the design of prevention strategies, especially when effective vaccines against the disease are available.

Maximum entropy modeling risk of anthrax in the Republic of Kazakhstan

The objective of this study was to zone the territory of the Republic of Kazakhstan (RK) into risk categories according to the probability of anthrax emergence in farm animals as stipulated by the re-activation of preserved natural foci. We used historical data on anthrax morbidity in farm animals during the period 1933 - 2014, collected by the veterinary service of the RK. The database covers the entire territory of the RK and contains 4058 anthrax outbreaks tied to 1798 unique locations. Considering the strongly pronounced natural focality of anthrax, we employed environmental niche modeling (Maxent) to reveal patterns in the outbreaks' linkages to specific combinations of environmental factors. The set of bioclimatic factors BIOCLIM, derived from remote sensing data, the altitude above sea level, the land cover type, the maximum green vegetation fraction (MGVF) and the soil type were examined as explanatory variables. The model demonstrated good predictive ability, while the MGVF, the bioclimatic variables reflecting precipitation level and humidity, and the soil type were found to contribute most significantly to the model. A continuous probability surface was obtained that reflects the suitability of the study area for the emergence of anthrax outbreaks. The surface was turned into a categorical risk map by averaging the probabilities within the administrative divisions at the 2nd level and putting them into four categories of risk, namely: low, medium, high and very high risk zones, where very high risk refers to more than 50% suitability to the disease re-emergence and low risk refers to less than 10% suitability. The map indicated increased risk of anthrax re-emergence in the districts along the northern, eastern and south-eastern borders of the country. It was recommended that the national veterinary service uses the risk map for the development of contra-epizootic measures aimed at the prevention of anthrax re-emergence in historically affected regions of the RK. The map can also be considered when developing large-scale construction projects in the areas comprising preserved soil foci of anthrax.

ACTUAL TICK-BORNE INFECTIONS IN CRIMEA

The Crimean Peninsula is located in the Northern part of the Black sea, from the East it is washed by the Sea of Azov, to the South and West by the Black Sea. The unique geographical and climatic conditions facilitate leptospirosis, tularemia, tick-borne encephalitis, Lyme disease, intestinal yersiniosis, pseudotuberculosis, hemorrhagic fever with renal syndrome, Crimean-Congo hemorrhagic fever, Mediterranean fever, Q-fever and other infectious diseases natural foci formation on the territory of Crimea Republic. Tick-borne natural focal infections have the most significance due to favorable epidemiologic conditions especially on the background of high raid ticks attacks on people. A leading role in the epizootology and epidemiology of tick-borne natural-focal infections of the Crimea are playing Ixodidae that occur in different landscape-climatic zones, with the greatest their species diversity is observed in mountain-foothill, forest and forest-steppe regions. There are about 30 species in Ixodidae fauna of the Crimean Peninsula. Ticks species composition identification shows that over 50% of people attacks episodes in the Crimea on recent years is caused by Ixodes ricinus ticks species, the remaining are associated with Haemophisalis punctata, Rhipicephalus sanguineus, Hyalomma marginatum, Dermacentor marginatus and other. Refusal of treatment in medical institutions of the people affected by tick bites, and the possibility of an attack on people subtle phases of mites are lubricates the real picture of the frequency of contacts of the population with ticks and complicates the forecasting of the epidemiological situation. This review summarizes the available information about spreading of tick-borne encephalitis, Lyme disease, Mediterranean and Crimean-Congo haemorrhagic fevers on the territory of Crimea Republic and demonstrates the modern trends and manifestations of epidemic process of these nosological forms. The results obtained in the analysis of our investigations and literature data, showed that the conditions of globalization lead to an increase in the frequency of contacts of the population with natural foci, and one of the most common tick-borne natural focal infections on the territory of the Peninsula are Lyme disease and the Mediterranean fever. Epidemiological analysis of the prevalence of tick-borne encephalitis and Crimean-Congo haemorrhagic fever in Crimea revealed a decrease in the activity of natural foci of these infections at the present stage. The problem of tick-borne natural focal infections in Crimea Republic requires further careful study.

An Online Atlas for Exploring Spatio-Temporal Patterns of Cancer Mortality (1972-2011) and Incidence (1995-2008) in Taiwan

Public health mapping and Geographical Information Systems (GIS) are already being used to locate the geographical spread of diseases. This study describes the construction of an easy-to-use online atlas of cancer mortality (1972-2011) and incidence (1995-2008) in Taiwan.Two sets of color maps were made based on "age-adjusted mortality by rate" and "age-adjusted mortality by rank." AJAX (Asynchronous JavaScript and XML), JSON (JavaScript Object Notation), and SVG (Scaling Vector Graphic) were used to create the online atlas. Spatio-temporal patterns of cancer mortality and incidence in Taiwan over the period from 1972 to 2011 and from 1995 to 2008.The constructed online atlas contains information on cancer mortality and incidence (http://taiwancancermap.csmu-liawyp.tw/). The common GIS functions include zoom and pan and identity tools. Users can easily customize the maps to explore the spatio-temporal trends of cancer mortality and incidence using different devices (such as personal computers, mobile phone, or pad). This study suggests an easy- to-use, low-cost, and independent platform for exploring cancer incidence and mortality. It is expected to serve as a reference tool for cancer prevention and risk assessment.This online atlas is a cheap and fast tool that integrates various cancer maps. Therefore, it can serve as a powerful tool that allows users to examine and compare spatio-temporal patterns of various maps. Furthermore, it is an-easy-to use tool for updating data and assessing risk factors of cancer in Taiwan.

A Serological Survey About Zoonoses in the Verkhoyansk Area, Northeastern Siberia (Sakha Republic, Russian Federation)

In 2012, a seroprevalence survey concerning 10 zoonoses, which were bacterial (Lyme borreliosis and Q fever), parasitic (alveolar echinococcosis [AE] and cystic echinococcosis [CE], cysticercosis, toxoplasmosis, toxocariasis, and trichinellosis), or arboviral (tick-borne encephalitis and West Nile virus infection), was conducted among 77 adult volunteers inhabiting Suordakh and Tomtor Arctic villages in the Verkhoyansk area (Yakutia). Following serological testing by enzyme-linked immunosorbent assay and/or western blot, no positive result was found for cysticercosis, CE, toxocariasis, trichinellosis, and both arboviral zoonoses. Four subjects (5.2%) had anti-Toxoplasma IgG, without the presence of specific IgM. More importantly, eight subjects (10.4%) tested positive for Lyme borreliosis, two (2.6%) for recently acquired Q fever, and one (1.3%) for AE. Lyme infection and Q fever, whose presence had not been reported so far in Arctic Yakutia, appeared therefore to be a major health threat for people dwelling, sporting, or working in the Arctic area of the Sakha Republic.

Evolution of research in health geographics through the International Journal of Health Geographics (2002-2015)

Health geographics is a fast-developing research area. Subjects broached in scientific literature are most varied, ranging from vectorial diseases to access to healthcare, with a recent revival of themes such as the implication of health in the Smart City, or a predominantly individual-centered approach. Far beyond standard meta-analyses, the present study deliberately adopts the standpoint of questioning space in its foundations, through various authors of the International Journal of Health Geographics, a highly influential journal in that field. The idea is to find space as the common denominator in this specialized literature, as well as its relation to spatial analysis, without for all that trying to tend towards exhaustive approaches. 660 articles have being published in the journal since launch, but 359 articles were selected based on the presence of the word “Space” in either the title, or the abstract or the text over 13 years of the journal’s existence. From that database, a lexical analysis (tag cloud) reveals the perception of space in literature, and shows how approaches are evolving, thus underlining that the scope of health geographics is far from narrowing.

Health risks facing travelers to Russia with special reference to natural-focal diseases

BACKGROUND

Russia, an enormous country almost completely located within temperate latitudes, has a broad spectrum of natural landscapes which attract increasing numbers of tourists, from arctic deserts in the north to steppes and deserts in the south. Currently, tourism is undergoing active development in Russia: new travel routes, including ones that involve visiting the wilderness, are steadily appearing. Among the multitude of infectious diseases that can endanger travelers, natural-focal diseases, whose agents and/or carriers are integral to natural landscapes, are especially prominent. Some of the results of the study of natural-focal infections and parasitoses, which are necessary to evaluate the recreational and travel potential of the Russian Federation, are presented and discussed in this article.

METHOD

A cartographical and statistical analysis of infectious and parasitic natural-focal diseases, spanning more than a decade (1997-2013), is the basis of this article.

RESULTS

This analysis, along with that of additional cartographical and textual sources, reveals that natural-focal infections are most diverse between 48° N and 60° N and least diverse in the northern regions of the Far East of Russia. Different regions have different numbers of nosoforms and different morbidity level, which signifies an irregularity in the distribution of parasitic diseases.

CONCLUSIONS

This medico-geographical information may be useful both for individual tourists planning trips to Russia and tour agencies organizing tour groups. It also can be used by health advisers when they consult people before a trip, to assess the actual risks, suggest a number of precautions and pick the particular diseases out of those listed that actually constitute a risk in certain regions, and suggest a suitable preventative treatment if needed.