West Nile fever is an infection by the West Nile virus, which is typically spread by mosquitoes. In about 80% of infections people have few or no symptoms. About 20% of people develop a fever, headache, vomiting, or a rash. In less than 1% of people, encephalitis or meningitis occurs, with associated neck stiffness, confusion, or seizures. Recovery may take weeks to months. The risk of death among those in whom the nervous system is affected is about 10%.West Nile virus (WNV) is usually spread by ...

west nile fever

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Author: Rositsa Tashkova, Master of Molecular Biology and Microbiology

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Nothing spoils the mood in spring and summer as annoying biting insects - which seem to fly on swarms to draw on our blood. However, itching is our smallest problem - mosquitoes and ticks are insidious in that they transmit dangerous diseases.

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Ticks carry the following dangerous (deadly) diseases:

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<ul>
<li style="font-weight: 400;" aria-level="1">Lyme disease;</li>
<li style="font-weight: 400;" aria-level="1">Tick encephalitis;</li>
<li style="font-weight: 400;" aria-level="1">Q-fever;</li>
<li style="font-weight: 400;" aria-level="1">Hemorrhagic fever with kidney syndrome;</li>
<li style="font-weight: 400;" aria-level="1">Crimean-Congo hemorrhagic fever;</li>
<li style="font-weight: 400;" aria-level="1">Marseilles fever and others.</li>
</ul>

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Mosquitoes carry very dangerous diseases such as:

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<ul>
<li style="font-weight: 400;" aria-level="1">Malaria;</li>
<li style="font-weight: 400;" aria-level="1">West Nile fever;</li>
<li style="font-weight: 400;" aria-level="1">Dengue;</li>
<li style="font-weight: 400;" aria-level="1">Yellow fever.</li>
</ul>

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Among the most effective repellents against these insects are chemical ones containing the substances DEET (N,N-diethyl-3-methylbenzamide, formerly known as N,N-diethyl-m-toluamide) or icaridin (picaridin), but they are not always suitable for use.

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DEET may show neurotoxicity in its use in combination with sunscreen and is not recommended in pregnant women unless it is extremely necessary and the risks of infection are greater than the risk of the chemical's effects on the foetus. It cannot be used in children under 2 years of age.

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Plant-based repellents are the alternative to chemical repellents (although their action, of course, is also due to chemicals ;) ). In the following lines we will consider which plants and substances from them offer protection against mosquitoes, ticks, and in some cases flies and biting midges. [<a href="https://www.bioseek.eu/en/eng/research/pubmed/Chemical_and_Plant_Based_Insect_Repellents_Efficacy_Safety_and_Toxicity_26827259" target="_blank" rel="noopener">ref.1</a>]

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Lemon-scented Gum Tree or Lemon Eucalyptus Oil

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The effect of lemon eucalyptus (Corymbia citriodora or Eucalyptus citriodora) is due to the substance p-mint-3,8-diol. It offers good protection against mosquitoes and ticks, which lasts up to 2 hours, protecting better from ticks compared to DEET. Also protects against biting midges.

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At home, a mixture of 1 part lemon eucalyptus oil and 10 parts of sunflower oil can be prepared. Apply as a spray.

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Not suitable for children under 3 years and sufferers of atopic dermatitis.

Permethrin

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The substance is derived from crushed dried colors of Dalmatian chrysanthemum (Chrysanthemum cinerarifolium). It is highly effective against mosquitoes, ticks, fleas and biting midges, but it is applied to clothes, nets, sleeping bags, and not on the skin. It does not damage the fabrics of clothes and plastics. It is necessary to re-apply it only after 5-10 or more laundry cycles.

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It is even more effective when used in combination with other repellents that are put on the skin. In direct contact, it causes insect paralysis, leading to its death.

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Unfortunately, mosquito resistance to permethrin has been observed in recent years.

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Citronella

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It is extracted from lemongrass (Cymbopogon spp.) and offers weak protection only against mosquitoes for up to 2 hours. Its activity is due to the substance 3,7-dimethyloct-6-en-1-al. It is used in the form of candles, oil or lotion.

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It can damage clothes and cause irritation on the skin, eyes or cause an allergy.

Essential-Oils

Essential Oils

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The most effective essential oils against mosquitoes are [ <a href="https://www.bioseek.eu/en/eng/research/pubmed/Plant_based_insect_repellents_a_review_of_their_efficacy_development_and_testing_21411012" target="_blank" rel="noopener">ref.2</a>]:

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<ul>
<li style="font-weight: 400;" aria-level="1">thyme oil (Thymus vulgaris),</li>
<li style="font-weight: 400;" aria-level="1">geraniol,</li>
<li style="font-weight: 400;" aria-level="1">mint oil</li>
<li style="font-weight: 400;" aria-level="1">cedar oil,</li>
<li style="font-weight: 400;" aria-level="1">patchouli (Pogostemon cablin),</li>
<li style="font-weight: 400;" aria-level="1">cloves (Syzygium aromaticum).</li>
</ul>

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Their activity varies between 60 and 180 minutes, since most of these essential oils are highly volatile and soon evaporate. This problem can be solved by using fixatives or careful formulation to improve durability.

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It should be considered that essential oils can irritate the skin and their repellent effect is variable depending on the formulation and concentration. The combination of essential oil and sun can lead to further irritation of the skin. Essential oils are never used directly on the skin undiluted, but always in combination with a carrier oil.

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How-To-Relieve-Itching-From-Bites

How To Relieve Itching From Bites

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Besides hydrocortisone cream from the pharmacy or calamine lotion, there are several homemade remedies that you can try to relieve unpleasant itching from bites:

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<ul>
<li style="font-weight: 400;" aria-level="1">Put a piece of raw onions on the site of the bite;</li>
<li style="font-weight: 400;" aria-level="1">Put freshly chopped garlic on the bite;</li>
<li style="font-weight: 400;" aria-level="1">Rub apple cider vinegar on the affected skin;</li>
<li style="font-weight: 400;" aria-level="1">Smear the bite with a paste of baking soda and water;</li>
<li style="font-weight: 400;" aria-level="1">Put on a cold compress;</li>
<li style="font-weight: 400;" aria-level="1">Place a chilled used bag of chamomile tea on the spot;</li>
<li style="font-weight: 400;" aria-level="1">Smear the bite with thyme tea;</li>
<li style="font-weight: 400;" aria-level="1">Smear the bite with a pre-prepared extract of St. John's wort in olive oil.</li>
</ul>

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If nothing helps, just try to focus your attention on something else and avoid scratching, because it will lead to skin damage and potential infection, as well as slower resolution of itching and discomfort.

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Nature offers several effective means to prevent attacks by mosquitoes, ticks and other bloodsuckers carrying severe diseases. However, in areas with a high prevalence of these infections, it is advisable to use chemical repellents such as DEET, which give greater certainty and long-lasting effect. This is especially true when travelling in some more exotic destinations.