Ecological niche modelling of potential West Nile virus vector mosquito species and their geographical association with equine epizootics in Italy.

This study uses ecological niche modelling to map potential habitats for West Nile Virus-transmitting mosquitoes in Italy and explores their geographical correlation with outbreaks of the disease in horses. It provides crucial insights into the environmental factors contributing to mosquito distribution, which can aid in anticipating and managing the spread of the disease.

Thorough Explanation

The research focused on modelling how 13 mosquito species potentially carrying the West Nile virus (WNV) could be distributed across Italy in response to different environmental factors. These predictions were then linked with occurrence data for outbreaks of the virus among horses recorded from 2008 to 2010.

• The modelling software Maxent applied was intended to generate ecological niche models for the 13 mosquito species, considering factors such as location and environmental conditions.
• The species screened included Culex pipiens, Aedes albopictus, Anopheles maculipennis, Culex modestus, Ochlerotatus geniculatus, Ochlerotatus caspius, Coquillettidia richiardii, Aedes vexans, Anopheles plumbeus, Aedes cinereus, Culex theileri, Ochlerotatus dorsalis, and Culiseta longiareolata.
• The model predicted suitable habitats for each species considering multiple environmental variables. It identified that elevation, temperature, and precipitation had the highest influence on the species distribution. However, the presence of the host population and landscape variables also contributed, but to a lesser extent.
• The predictive models showed a widespread distribution of suitable habitats for mosquito species such as Culex pipiens, Aedes albopictus, and Anopheles maculipennis across Italy, while others like Culex modestus, Ochlerotatus geniculatus, and Coquillettidia richiardii had their suitable habitats concentrated in the north-central regions. Aedes cinereus and Culex theileri were restricted to the coastal and southern areas.
• The researchers associated the predicted WNV mosquito habitat distributions with recorded WNV outbreak locations among equines. The results suggested a significantly higher likelihood of disease outbreaks in the areas suitable for Cx. modestus and Cx. pipiens, indicating a geographical overlap between the predicted distribution of these species and the observed distribution of the disease in horses.

In summary, the research provides a valuable understanding of the role of environmental variables in shaping mosquito species distributions associated with WNV. These insights can contribute significantly to creating predictive models for disease outbreaks and guiding practices for prevention and management.