Mosquitoes facts, Malaria, Dengue Prevention

aedes albopictus mosquito

A female (Asian) Tiger mosquito (Aedes Albopictus) having dinner.

This is a female of the Aedes species that is responsible for Dengue fever, Chikungunya and Zika. Malaria is delivered by the female Anopheles mosquito (photo below). Another pest, Aedes Aegypti, looks very similar and has the same distinctive white markings. However, just because the mozzie has white bands doesn’t mean it’s infected with anything! It’s probably just irritating but harmless. Relax. Well, kill it then relax.

Mosquito bites, avoidance and disease symptoms – Zika, Malaria, Dengue

Zika virus

The CDC (the US Centre for Disease Control)  informs us that Zika mosquitoes can be found in the Caribbean, Central and South America, Pacific Islands,  Singapore, and within the United States, specifically Florida (at the moment).
The effects are generally mild but the concern is about a probable link with brain defects in babies.
If in any doubt head elsewhere for your vacations BUT if pregnancy is not an issue due to contraception, age or gender then this may be a good time to travel in Latin America as competition for rooms and sun beds is likely to be lower than normal.

Pregnancy and travel

Only pregnant women have been advised to reconsider their plans to visit countries affected by Zika.
It is thought that within the female body the virus can travel across the placenta and affect the health of an unborn baby.
There has been a surge in microcephaly – in which the baby’s brain does not develop properly – in Brazil.

Pregnant women should reconsider their travel plans and travellers should seek advice from a health professional before departing.
Pregnant women who have to travel should take ‘scrupulous’ measures to avoid being bitten by mosquitoes.
The US Centers for Disease Control says women trying to get pregnant should “talk to your doctor about your plans to become pregnant and the risk of Zika virus infection and strictly follow steps to prevent mosquito bites during your trip.”

Is it safe to get pregnant after travel?

The CDC says Zika lingers in the blood for approximately a week.
And: “The virus will not cause infections in a baby that is conceived after the virus is cleared from the blood.
“There is currently no evidence that Zika virus infection poses a risk of birth defects in future pregnancies.”

What about men?

Zika can be passed through sex from a person who has Zika to his or her partners, even if the infected person does not have symptoms at the time.

  • It can be passed from a person with Zika before their symptoms start, while they have symptoms, and after their symptoms end.
  • Though not well documented, the virus may also be passed by a person who carries the virus but never develops symptoms.
  • Studies are underway to find out how long Zika stays in the semen and vaginal fluids of people who have Zika, and how long it can be passed to sex partners.  Zika can remain in semen longer than in other body fluids, including vaginal fluids, urine, and blood.

It is thought the virus can persist in semen for two weeks after a man recovers from an infection.
Very few countries have specific advice for men.
Public Health England is taking a safety-first approach after one suspected case of sexual transmission.
The organisation says the risk of spreading the virus through sex is “very low” and at this stage only “theoretical”.
But it recommends using condoms if you have a pregnant partner or one who might become pregnant.
This should be done for 28 days after coming home and if you have no symptoms, and for six months if Zika symptoms do develop.

West Nile virus

West Nile virus is a problem in the USA which has killed two or three hundred people in the last two years.

The viral transmitting mosquitoes have now appeared in southern Europe including Portugal, Spain and France. So how can you avoid these sometimes deadly infections?
The best way to avoid Malaria, Dengue Fever and West Nile virus (not to mention rarer but equally unpleasant health threats such as Encephalitis, Triple E, Yellow Fever, Rift Valley fever and more) is to keep the little stingers off you.

Triple E virus: Eastern Equine Encephalitis

Fresh into the mosquito-borne disease spotlight is the USA’s Triple E virus, Eastern Equine Encephalitis, which is found in north eastern US locations such as Rhode Island. It is rarely transmitted to humans (averaging 5 cases per year; birds are the main recipient of Triple E), but when it is, it’s deadly, killing a third of those infected. There is no cure or vaccine, so keeping mozzies off is the only defence.

Avoiding Mosquitoes

Zika, Dengue and Chikungunya  are spread by the Aedes mosquito species which is most active during the day but also flies at dawn and dusk.
People are advised to:

* Cover up with long-sleeved shirts and trousers
* Use insect repellents such as those containing DEET, picaridin or IR3535, the stronger the better though, for example, DEET over 50% is not good for delicate skin. Put it on clothes instead (T-shirt near neck and arms, shorts near bare legs etc.) If you prefer a natural product try one of these repellents.
* Apply sunscreen before using applying insect repellent
* Keep doors and windows closed and to use air conditioning

p.s. If you get bitten and the spot is itchy, try ‘ironing’ it with a hot cup of tea or coffee – it will magically disappear! Alternatively try squeezing lemon juice or apple cider vinegar or fresh cut onion/garlic onto it.

Outdoors, wear light colours – mosquitoes know their camouflage – long trousers and long sleeves.
Take especial care of bare ankles underneath restaurant tables, it’s the mosquito’s favourite dining area, a lovely cluster of veins close to the ground in discreet darkness. Mmm, yummy.
And they’ll get you through thin clothes too, so apply repellent to thin fabrics in key places e. g. socks, T-shirt shoulders.
Avoid wearing perfumes and shower off your body odour as soon as you can, as mosquitoes use smell to track their victims.
Indoors, hunt to splat. Look under beds, shake curtains, check dark places. In extremis spray the room with (esp. pyrethrum) insecticide, if it has window nets or air conditioning.
Electric anti-mosquito mats or electric liquid-wick-bottles are preferable for all-night protection rather than smouldering coils, as coils tend to run out before dawn, and are smelly, unhealthy devices anyway. But they are very effective.
When travelling in more primitive surroundings sleep under a net, treated with permethrin if possible. If not, mosquito coils are default best system.

Mosquito Repellents

– Deet. The most potent mosquito repellents contain lots of Deet (Diethyl-toluamide), so check out the ingredients.
25% Deet is good, 50% is excellent and 100% Deet will force mosquitoes to leave the country; trouble is it will also dissolve your skin, so only use it on clothes or nets. Be wary of using deet on the skin of small children. Try refined oils (see below) as an effective alternative.

Deet news 2015: Mosquitoes evolve very quickly according to Dr James Logan, London School of Hygiene and Tropical Medicine.
Research suggests that mosquitoes simply do not like the smell of Deet but appear to get used to it after a short time as their antenna receptors became de-sensitized.
Nevertheless Dr Logan says that deet is effective at first/in many cases and visitors to high risk areas should continue to use it.

– Picaridin and IR3535 are also recommended mosquito-effective ingredients and are safe for pregnant women

Mosiguard is relatively natural (citrodiol and eucalyptus) and often very effective, so starting with that and saving the Deet for heavy duty mozzie attacks is worthwhile.

– Tea Tree Oil is what I’ve been using recently in southern Europe, it’s cheap and effective, tho’ not tested (by me) in tropical climates.

– Refined lemon eucalyptus oil, Greek Catnip oil, Lavender oil, Tea Tree oil, Soy Bean oil and citronella oil, all  are disliked by insects; but  dilute them with some kind of carrier oil, such olive, sunflower or sesame, a few drops per teaspoon of carrier oil is generally effective but the product and strength needed will depend on the type of mosquitoes in your environment.
Also/alternatively bath or shower with lemon gel.
– NeemCare Herbal Insect Repellent. Neem tree oil is used in Ayurvedic medicine and is burned in India to repel insects.
It is now on the market as a general repellent and in tests has successfully repelled the voracious midges that plague the Scottish Highlands as well as mosquitoes.
If mosquitoes do get through the defences, trials indicate that Neem oil also reduces the severity of the body’s reaction to the bite.
Personally tested when travelling in Myanmar, it worked perfectly. Available in health stores and pharmacies, it also works against head lice.

– Vitamin B1/B12. Consistent anecdotal evidence suggests that mozzies hate the smell of B1. Take 100mg a day, starting a few days before your trip. Others swear by B12. They’re both worth trying if you plan to spend a while in mosquito disease zones.

– Fish Oil capsules. e. g. Cod Liver Oil.
It must be unrefined so there is a hint of fishy smell about your person. Take a few days before leaving to build up the odour.
Think about it. . . fish eat mozzies and their larvae, so a mosquito will have an intense aversion to fish. Some people swear by this solution.

– Quercetin. You can also strengthen your body’s health system before travelling by taking an anti-inflammatory called quercetin, which is especially effective when taken with Vitamin C.
– One ‘deterrent’ is smelly socks! Scientists in Tanzania have discovered that mosquitoes prefer the odour of very smelly socks than humans, by a factor of 4: 1. In other words – a) wash your feet after a long hike and put your socks well away from your camp b) or you could try creating a box shrouded in insecticide cloth to kill the little buzzers.

– Electric ‘vape’ mats and the liquid version work well in rooms, are relatively inoffensive and last longer than coils, but check local voltage and socket type.

– Electronic buzzers/sonic deterrents do not work as far as our experience goes.