Flying insects like bees or wasps can easily enter from or to remote areas. They mostly live in nests in big populations.
Being confronted with human beings, these insects can activate their defense instinct and stitch their stings into nearby persons.
Combined with the stitch, poison is injected into the skin of the affected human, who will be suffering from swellings, itching and reddened skin.
In some cases, especially if people develop allergic reactions, consequences can be more severe.
To retain bees and wasps out of your area, Professional Pest Control