No abstract

We extend a previously developed epidemiological model for West Nile virus (WNV) infection in humans in Greece, employing laboratory-confirmed WNV cases and mosquito-specific characteristics of transmission, such as host selection and temperature-dependent transmission of the virus. Host selection was defined by bird host selection and human host selection, the latter accounting only for the fraction of humans that develop symptoms after the virus is acquired. To model the role of temperature on virus transmission, we considered five temperature intervals (≤ 19.25 °C; > 19.25 and < 21.75 °C; ≥ 21.75 and < 24.25 °C; ≥ 24.25 and < 26.75 °C; and > 26.75 °C). The capacity of the new model to fit human cases and the week of first case occurrence was compared with the original model and showed improved performance. The model was also used to infer further quantities of interest, such as the force of infection for different temperatures as well as mosquito and bird abundances. Our results indicate that the inclusion of mosquito-specific characteristics in epidemiological models of mosquito-borne diseases leads to improved modelling capacity.

&lt;p&gt;The transmission of West Nile Virus is known to be affected by multiple factors related to the behavior and interactions between reservoir (birds), vector (&lt;em&gt;Culex&lt;/em&gt;-mosquitos), and hosts (humans). Environmental parameters can play a critical role in understanding WNV epidemiology. The aim of this research was to determine the association of various climatic factors with the &lt;em&gt;Culex&lt;/em&gt; mosquito abundance in Greece during the period 2011-2022. Climate data were acquired from ERA5 (European Centre for Medium-Range Weather Forecasts), while &lt;em&gt;Culex&lt;/em&gt; abundance data were obtained through the mosquito surveillance network of ECODEVELOPMENT S.A, who hold the biggest mosquito surveillance network in Greece. The research was conducted at the municipality level. &lt;em&gt;Culex&lt;/em&gt; abundance depends in a nonlinear fashion from temperature (Figure 1). The spread of the measurements indicates however there are other factors that affect the abundance of mosquitoes.&lt;/p&gt; &lt;p&gt;&lt;img src=&quot;&quot; alt=&quot;&quot; /&gt;&lt;/p&gt; &lt;p&gt;&lt;em&gt;Figure 1 Scatter plot of air temperature VS Culex abundance in a municipality (Delta) with relatively sizeable mosquito population.&lt;/em&gt;&lt;/p&gt; &lt;p&gt;Correlation heatmaps were used as a tool to visualize the correlation of vector abundance and average monthly temperature up to 2 months before at several municipalities in the Region of Central Macedonia. The correlations decrease with increasing the lag in temperature (Figure 2). Moreover, there are some municipalities in which the correlation coefficient is considerably greater than others. Those correlations cannot be explained without considering the mosquito breeding sites found in these municipalities. In these municipalities there is a presence of important water resources, such as rice paddies, drainage canals, wetland systems or a combination of all the above. When surface waters warm and the outside temperature rises, the mosquito life cycle is completed more quickly, resulting in more generations being produced in a shorter period of time.&lt;/p&gt; &lt;p&gt;&lt;img src=&quot;&quot; alt=&quot;&quot; /&gt;&lt;/p&gt; &lt;p&gt;&lt;em&gt;Figure 2 Correlation heatmap of the correlation coefficient between the mosquito abundance (municipality scale) and the average monthly temperature up to 2 months before.&lt;/em&gt;&lt;/p&gt; &lt;p&gt;Scatterplots and correlation heatmaps calculated with the &lt;em&gt;Culex&lt;/em&gt; abundance and total precipitation, relative humidity or wind speed did not reveal similar patterns. Ongoing analysis focuses in more factors, environmental and not, which affect the abundance of mosquitoes that transmit WNV.&lt;/p&gt; &lt;p&gt;&lt;strong&gt;Acknowledgments&amp;#160;&lt;/strong&gt;&lt;br /&gt;This research has been co&amp;#8208;financed by the European Regional Development Fund of the European Union and Greek national funds through the Operational Program Competitiveness, Entrepreneurship and Innovation, under the call RESEARCH &amp;#8211; CREATE &amp;#8211; INNOVATE (project code: &amp;#932;2&amp;#917;&amp;#916;&amp;#922;-02070).&amp;#160;&lt;/p&gt;

West Nile Virus (WNV) belongs to the flavivirus genus, and it is a neurotropic mosquito-borne virus. The virus transmitted among amplifying hosts, such as birds, transferred through the bites of mosquitoes and incidentally humans and other mammals may become infected. In elderly and immunocompromised people, symptomatic infections can result in neurologic diseases. There is currently no specific treatment or vaccine available for WNV. The transmission dynamics of WNV are complex and affected by various environmental factors, including temperature and total precipitation. Understanding the relationship between the environmental factors and WNV transmission is crucial for predicting and preventing outbreaks of the disease., while the prediction of an infectious disease outbreak is critical for reducing the potential impact on human health. A large proportion of WNV infections in humans present either asymptomatically or with some non-specific clinical symptoms and are unrecorded. The aim of this study is to explore the association between climatic factors and the occurrence of West Nile fever (WNF) in humans at a finer than NUTS-3 spatial scale (LAU). The investigation area is the region of Central Macedonia in Northern Greece, analyzing a unique dataset that includes meteorological data from ERA5 (European Centre for Medium-Range Weather Forecasts) and epidemiological data from the Hellenic National Public Health Organization for the period 2010-2022. The research focuses on this region because it is an area of great epidemiological interest. Specifically, at least one WNV human case has been recorded at all LAUs, while in 26% of the LAUs an extremely high number of cases have been recorded during the period of research. The analysis shows a strong correlation between the number of annual human cases of WNV and temperature and precipitation patterns in the months leading up to the outbreak. The results reveal the augmented forecast potential from temperature and precipitation anomalies in virus spread prediction models. Acknowledgments This research has been co&#8208;financed by the European Regional Development Fund of the European Union and Greek national funds through the Operational Program Competitiveness, Entrepreneurship and Innovation, under the call RESEARCH &#8211; CREATE &#8211; INNOVATE (project code: &#932;2&#917;&#916;&#922;-02070).