Geospatial epidemiology of coronary artery disease treated with percutaneous coronary intervention in Crete, Greece

Coronary artery disease (CAD) constitutes a leading cause of morbidity and mortality worldwide. Percutaneous coronary intervention (PCI) is indicated in a significant proportion of CAD patients, either to improve prognosis or to relieve symptoms not responding to optimal medical therapy. Thus the annual number of patients undergoing PCI in a given geographical area could serve as a surrogate marker of the total CAD burden there. The aim of this study was to analyze the potential, spatial patterns of PCItreated CAD patients in Crete. We evaluated data from all patients subjected to PCI at the island's sole reference centre for cardiac catheterization within a 4-year study period (2013-2016). The analysis focused on regional variations of yearly PCI rates, as well as on the effect of several clinical parameters on the severity of the coronary artery stenosis treated with PCI across Crete. A spatial database within the ArcGIS environment was created and an analysis carried out based on global and local regression using ordinary least squares (OLS) and geographically weighted regression (GWR), respectively. The results revealed significant inter-municipality variation in PCI rates and thus potentially CAD burden, while the degree and direction of correlation between key clinical factors to coronary stenosis severity demonstrated specific geographical patterns. These preliminary results could set the basis for future research, with the ultimate aim to facilitate efficient healthcare strategies planning.

Towards a Semi-Automatic Early Warning System for Vector-Borne Diseases.

The emergence and spread of vector-borne diseases (VBDs) is a function of biotic, abiotic and socio-economic drivers of disease while their economic and societal burden depends upon a number of time-varying factors. This work is concerned with the development of an early warning system that can act as a predictive tool for public health preparedness and response. We employ a host-vector model that combines entomological (mosquito data), social (immigration rate, demographic data), environmental (temperature) and geographical data (risk areas). The output consists of appropriate maps depicting suitable risk measures such as the basic reproduction number, R0, and the probability of getting infected by the disease. These tools consist of the backbone of a semi-automatic early warning system tool which can potentially aid the monitoring and control of VBDs in different settings. In addition, it can be used for optimizing the cost-effectiveness of distinct control measures and the integration of open geospatial and climatological data. The R code used to generate the risk indicators and the corresponding spatial maps along with the data is made available.

Risk Mapping of Visceral Leishmaniasis: A Spatial Regression Model for Attica Region, Greece.

Visceral Leishmaniasis (VL) is endemic to the Attica region of Greece. The geographical distribution of VL cases was analyzed employing methods of spatial analysis in a GIS environment. A geographic database was constructed including data for the disease cases and environmental factors, such as land cover types, stray dog population, and socioeconomic factors. Classic and spatial regression models are presented that suggest the factors contributing most to the incidence of leishmaniasis are green urban areas and the population of stray dogs in the municipalities of Attica region. The results of the spatial regression model were more accurate, thus were used to produce a disease risk map. This map indicates the high-risk municipalities in which surveillance for the control of leishmaniasis is necessary.

The epidemiology of Brucellosis in Greece, 2007-2012: a 'One Health' approach.

Background: Brucellosis remains a disease that is very difficult to control and eradicate in Greece. Information exchange between the responsible authorities is crucial in order to support public health infrastructure in the sense of the 'One-Health' strategy model. Methods: The data for 2007-2012 were retrieved from the notifiable diseases system and analysed statistically for correlations between human brucellosis cases and the disease in small ruminants. Disease-related risk factors were also estimated with parallel exploitation mapping software. Results: In Greece the dominant strain for brucellosis is Brucella melitensis. The average incidence in Greece was estimated to be 1.43/100,000. The majority of human cases were males (67.60%). The age distribution of brucellosis patients differs significantly between men and women. Brucellosis in male patients was related to high risk jobs and animal contact, while brucellosis in females was related to recent consumption of dairy products. Seasonality of the disease was different in relation to the European countries an observation attributed to the traditional customs. There was a statistically significant difference in human brucellosis incidence between the eradication and vaccination zones. Conclusion: The updated information on brucellosis in Greece revealed differences in seasonality and transmission patterns. A more active cooperation between the involved public health-related sectors should be followed in order to effectively fight brucellosis as there are still foci of brucellosis in Greece.

A spatial predictive model for malaria resurgence in central Greece integrating entomological, environmental and social data.

Malaria constitutes an important cause of human mortality. After 2009 Greece experienced a resurgence of malaria. Here, we develop a model-based framework that integrates entomological, geographical, social and environmental evidence in order to guide the mosquito control efforts and apply this framework to data from an entomological survey study conducted in Central Greece. Our results indicate that malaria transmission risk in Greece is potentially substantial. In addition, specific districts such as seaside, lakeside and rice field regions appear to represent potential malaria hotspots in Central Greece. We found that appropriate maps depicting the basic reproduction number, R0, are useful tools for informing policy makers on the risk of malaria resurgence and can serve as a guide to inform recommendations regarding control measures.

Species composition, distribution, ecological preference and host association of ticks in Cyprus.

Tick population and species depend on the effect of biotic and abiotic factors, especially vegetation, climate and host density; Cyprus, due to the mild climate, favors the appearance and spread of tick-borne infections. Our objective was to identify the tick species present in the island, to investigate their geographical distribution and their epidemiological implications. During a three-year study (2004-2006) we collected ticks from domestic and wild animals over the island of Cyprus. Data on temperature, humidity, altitude and vegetation, were also recorded. Each tick was identified by species using existing taxonomic keys. The results were mapped on a county level. During the current study 3057 ticks belonging to 11 tick species and four genera were collected from 441 (24.6%) infested animals. Rhipicephalus sanguineus was the predominant species (38.5%), followed by R. turanicus (21.3%) and R. bursa (17.8%). Most infestations occurred in May (24.0%), followed by March (13.6%) and June (12.2%). Rhipicephalus sanguineus had a positive correlation with humidity and temperature, R. bursa and Ixodes gibbosus had a positive correlation with altitude and a negative correlation with temperature. Contrary, Hyalomma excavatum had a negative correlation with altitude. Climate and the availability of hosts are among the major factors influencing ticks.

A novel AP92-like Crimean-Congo hemorrhagic fever virus strain, Greece.

Ticks were collected from various regions of northern Greece and tested for the presence of Crimean-Congo hemorrhagic fever virus (CCHFV) RNA. Human and animal sera were collected in the regions where CCHFV-positive ticks were detected, and they were tested for the presence of IgG antibodies against the virus. A CCHFV strain was detected in Rhipicephalus bursa ticks collected from sheep in Kastoria regional unit, differing by 9.7% at the nucleotide level from the AP92 strain, which was isolated in 1975 in another region of Greece. Up to date, CCHF cases have not been reported in these regions. The human seroprevalence in the area was estimated at 6%, while IgG-positive sheep was detected in two of the four neighboring farms tested. The circulation of this specific CCHFV lineage in Greece, especially in a region where the seroprevalence is high, together with the lack of human CCHF cases, suggests a probable antigenic, but non- or low-pathogenic character of this lineage. Further studies on these strains will increase our knowledge about the role of AP92-like strains in the CCHF epidemiology, which might be useful for drug and vaccine design.

Crimean-Congo hemorrhagic fever: seroprevalence and risk factors among humans in Achaia, western Greece.

BACKGROUND: The Crimean-Congo hemorrhagic fever virus (CCHFV) presents a wide distribution, with the Balkan Peninsula being among the endemic regions. To date, only one CCHF case has been reported in Greece; however, based on seroprevalence data, there is evidence that CCHFV circulates in the country. Achaia is a prefecture in western Greece that has not previously been studied for CCHFV. OBJECTIVES: The aim of this study was to estimate the seroprevalence of CCHFV in humans in Achaia Prefecture, Greece, and to assess possible factors playing a role in seropositivity. METHODS: A total of 207 serum samples from people of all age groups, from both urban and rural areas, were prospectively collected and tested for IgG antibodies against CCHFV. RESULTS: The overall seroprevalence was 3.4%, with significant differences among municipalities. An agro-pastoral occupation, contact with sheep and goats, former tick bite, increasing age, and living at an altitude of ≥400 m, on specific land cover types, were significantly associated with CCHFV seropositivity. CONCLUSIONS: A relatively high seroprevalence was detected in a previously unstudied region of Greece, where CCHFV infection seems to occur mainly through tick bites. Further investigations are needed to identify the circulating CCHFV strains in Greece, in order to gain a better understanding of CCHFV ecology and epidemiology in the country.

Factors associated with IgG positivity to Crimean-Congo hemorrhagic fever virus in the area with the highest seroprevalence in Greece.

In order to gain insight into the factors playing a role for the high seroprevalence of Crimean-Congo hemorrhagic fever virus in the human population of Thesprotia prefecture, Greece, serum samples were collected from residents of the area together with a questionnaire about demographic and epidemiological factors. A 14.4% seroprevalence was detected, with increased age, agro-pastoral activities, slaughtering, and contact with animals (especially sheep) among the factors associated with seropositivity. The high seroprevalence with the absence of any clinical cases needs further investigation.

Rats as indicators of the presence and dispersal of pathogens in Cyprus: ectoparasites, parasitic helminths, enteric bacteria, and encephalomyocarditis virus.

Rodents play an active role in the transmission of a number of zoonoses by harboring and disseminating the pathogens involved, either through their biological materials or via their ectoparasites. Hence, the spatial and seasonal distribution of potential agents of zoonoses may be studied by examining their distribution in the rodent vectors and their ectoparasites. A surveillance was conducted in wild rodents in 51 different areas of Cyprus, an island ecosystem, to monitor the reemergence of Echinococcus granulosus and Encephalomyocarditis virus (pathogens that have been eradicated from Cyprus), to study the presence and dispersal of Salmonella spp. (a bacterium found in patients and poultry in the island), as well as to investigate the presence of helminth parasites and rodent ectoparasites. Biological material collected from 625 rodents, examined macroscopically, microscopically, and after culture, showed that the most widespread pathogens encountered in wild rats (Rattus rattus and Rattus norvegicus) were helminth parasites, found in 92 animals (three helminth species found for the first time in Cyprus: Cysticercus fasciolaris, Hymenolepis diminuta, and Physalloptera spp.), and Salmonella spp., detected in the intestine of 56 rats (12 different Salmonella spp. and serotypes). None of the rodents were found infected with the cestode Echinococcus or Encephalomyocarditis virus, indicating that the control measures taken by the Veterinary Services on the island prevented its reestablishment despite changing conditions. The rodents were also free of the nematode Trichinella. Over 40% of the rats collected were infested with fleas, mainly Xenopsylla cheopis. The results, analyzed using the Geographical Information System technology, revealed two of the areas studied as high risk for public health.

Leishmaniases and the Cyprus paradox.

In Cyprus, leishmaniasis has been considered exclusively a veterinary problem. It was prevalent before 1945, and until its recent reemergence, it was nearly eradicated by 1996 as a consequence of the destruction of reservoir hosts and vectors. A survey carried out to provide an unbiased estimate of current transmission rates in dogs and humans showed a 9-fold increase in dog seroprevalence (reaching 14.9%) compared with 10 years ago. However, no human cases caused by Leishmania infantum were detected, although L. donovani cases were reported recently. The 62 strains isolated from dogs were typed as L. infantum MON-1 (98.4%), which is the predominating zymodeme in the Mediterranean region, and MON-98 (1.6%). The Phlebotomus species P. tobbi (vector of L. infantum in Cyprus), P. galilaeus, and P. papatasi were the predominant species captured. Two transmission cycles seem to run in parallel in Cyprus: in dogs with L. infantum and in humans with L. donovani.

Thermal terrain modeling of spatial objects, a tool for environmental and climatic change assessment.

The aim of the current research effort is to include biophysical multi-temporal data and more specifically land surface temperature (LST) in the terrain modeling process that traditionally was based only on digital elevation data processing. The terrain partition framework (spatial objects) is defined by the borderlines of prefecture authorities of Greece. Each object is represented by a set of attributes derived from the digital elevation data, and objects are organized into clusters on the basis of their terrain dependent representation. Finally, the terrain is segmented to regions on the basis of the multi-temporal LST data, each region presenting a different thermal signature. The thermal regions are used in the spatial objects parametric representation and a new index is devised (LST climatic index) expressing the biophysical suitability of spatial objects at moderate resolution scale.