Deadly Mosquitoes - It's Not Just Malaria You Need To Worry About!
Mosquitoes - a very old species
The origin of mosquitoes goes back a long time. The oldest species known to date was found in a piece of amber from around 75 million years ago. They have subsequently developed into over 350,000 different species and continue to create havoc.
Mosquitoes belong to a family of midge-like flies of the group Culicidae. There are a few species that are harmless and probably even beneficial, but the majority are not only blood-sucking pests, they're dangerous. In fact a number of authorities have labelled the mosquito as the deadliest creature on Earth.
Most people have of course heard of the disease malaria that kills thousands of people all over the world. However, malaria is only one of the many diseases carried by this insect.
The life of the mosquito
The name mosquito comes from the Spanish or Portuguese - mosca ito - meaning 'little fly'. Similar to other species of flies they have a life-cycle that goes through four separate stages:
The female lays her eggs in stagnant water, although some species prefer either the water's edge or even aquatic plants. In fact most mosquitoes will adapt to whatever environment they are in. Therefore, some mosquito species will lay their eggs in lakes while others will use temporary water holders such as old tyres.
Some of the most dangerous mosquitoes are those that breed in plants that have natural water reservoirs known as phytotelmata. This is an area where rainwater has accumulated for example in the centre of plants or hole in a tree trunk. These species of mosquito can adapt any artificial reservoir into a breeding pond - pot plants, saucers it doesn't matter to some mosquitoes. This is particularly hazardous for humans because it brings the insect into close proximity to our homes. A mosquito species such as Aedes will use opportunistic areas such as those mentioned previously, but they also have the ability to pick up pathogens from humans and pass them on to other people.
As far as malaria goes there are four main forms caused by a parasite called Plasmodium:
- Plasmodium falciparum - this is the species of plasmodium that can causes malaria and can be fatal.
- Plasmodium vivax - causes a less serious form of malaria unlikely to prove fatal.
- Plasmodium ovale - as with vivax this is not usually a fatal form.
- Plasmodium malariae - as with vivax and ovale, this strain is more benign and unlikely to cause a fatality.
So let's take a closer look at the diseases mosquitoes carry and more importantly what they pass onto people.
Did you know?
That only the female mosquito drinks the blood of humans and other animals? This is not because she loves to drink blood, she simply needs the protein from blood to help her eggs develop. When she is not reproducing, the female prefers drinking nectar from flowers.
Did you know?
It's the carbon dioxide that we breath out that attracts mosquitoes to us. The insect can detect the gas from as far away as a staggering 75 feet!
Mosquitoes and the diseases they carry
In addition to people who live in mosquito areas, people are also travelling and taking vacations in wilder areas. This means that more people come into contact with the mosquito and inevitably the diseases they carry.
Malaria is the best known of the diseases but there are others that people need to be aware of when travelling through or staying in mosquito infested areas. It's also important that you receive full vaccinations recommended by your doctor. Even if you are young and very fit, this is no barrier to the mosquito.
Firstly I'll give a brief overview of malaria and then go onto the other diseases the insect carries.
Even today malaria is one of the biggest killers on the planet. If the fatal form of the disease is not treated quickly people can succumb to it rapidly.
The problem with malaria is that although symptoms can appear within a few days of being bitten, it's not uncommon for people to develop signs for weeks, months or even a year after the event.
The main symptoms to look for are listed in the UK NHS Choices as:
- Pain in the muscles
- Nausea and vomiting
- Feverish with chills and sweating - often described as severe flu-like symptoms
- Very tired
- High temperature - usually in the range of 38oC/100.4F.
Even if you have been home from your trip for several months and symptoms similar to the above develop, still go and see a doctor and explain that you have been in mosquito territory within the last year or so.
When treatment is commenced quickly, the recovery rate is faster and not usually lethal. Only when malaria goes untreated - as it does in many poor countries - will it kill. According to Dr Charlie Easmon of NetDoctor, about 1,500 people return to the UK from malaria regions and at least 12 of these people will die due to the disease.
Anti-malaria drugs are used to both prevent and treat malaria. However, the type of medicine used and how long it's used for will depend on:
- The type of malaria and also where you caught the disease.
- How severe your symptoms are.
- If you are pregnant then the dosage and length of treatment will vary.
- If you took anti-malarial medicine before getting a mosquito bite, then this wills also affect how much medicine you would be given and how long treatment would last.
Lets now look at other diseases the mosquito can transmit.
Did you know?
Some famous people who died of malaria:
1. Alexander the Great
2. Christopher Columbas
3. Poet - Lord Byron
4. Oliver Cromwell - although there is speculation that he was murdered by his doctor.
5. When Attila the Hun's army (452 AD) had just about sacked Rome, these mighty warriors were stopped in their tracks by the tiny parasite that causes malaria.
6. The famous Scottish explorer David Livingstone died from malaria and he also had dysentery.
Other diseases mosquitoes carry
Now that we've looked at malaria lets see what other diseases this little insect might have in store for you.
This disease - which is a virus - is known by a few names and is transmitted by the species of mosquito Aedes aegypti as well as some others. With a few people the disease goes into a toxic phase that causes jaundice - a yellowish colour - so giving rise to the name of 'Yellow Fever'.This phase can cause liver damage and lead to death.
Yellow fever is a haemorrhagic disease which means that damage can occur to the vascular system resulting in bleeding. However, the bleeding itself rarely causes death. The main symptoms are fever and chills, muscle pain, nausea, anorexia, headaches.
This is still a very serious and potentially lethal disease. It can be found in tropical areas such as South America and Africa. If travelling to the areas where yellow fever is endemic it's highly recommended that you get vaccinated against the virus as well as taking the usual precautions against mosquito bites.
This disease is also a virus spread by the mosquito. The majority of people usually have a mild strain of the illness but others can develop a more serious form. The virus is endemic in many tropical regions throughout the world especially India, Southeast Asia, Africa, South & Central America and the Caribbean.
The symptoms are very similar to flu with aching joints and muscles. In addition there could also be vomiting, diarrhoea, pain behind the ears and headache. There is also a rash that may develop. This is red in colour and starts at the chest before spreading to other areas of the body. First signs of the illness usually start about 5 to 8 days after being bitten.
Although most people recover there are others who go onto develop a more serious form - haemorrhagic dengue fever - that results in bleeding from the mouth and gums, blood in the faeces and it's not uncommon to vomit blood. Some people also develop dengue shock syndrome, where there is severe pain in the abdomen, vomiting, irritability and a severe lowering of body temperature.
There is no cure for dengue fever and no current vaccination, but most people are able to fight it off quite easily. It's only if the disease goes into a more serious stage that it can become lethal. To protect yourself, see the advice on avoiding mosquito bites at the end of this hub.
This is an inflammation of the brain. There are certain viruses carried by mosquitoes that can lead to this condition such as:
- La Crosse encephalitis
- West Nile encephalitis
- Eastern equine encephalitis
- Western equine encephalitis
- Venezuelan equine encephalitis
- St. Louis encephalitis
- Japanese encephalitis
These conditions are rare but can be fatal under certain circumstances - such as people over the age of 50 who have problems with their immune systems. At present there are no vaccines against these forms of encephalitis so preventative measures should be taken if the areas you are travelling to or live in have mosquitoes who carry any of these viruses.
For most people the virus only causes mild symptoms such as - vomiting, chills, fever, aches, fatigue and headache. However, some people can go onto develop a more serious form leading to encephalitis with symptoms such as - seizures, loss of vision, disorientated, paralysis and coma.
Lastly, we'll have a quick look at measures to prevent mosquitoes from biting.
How to prevent mosquito bites
Below are some of the best known methods to try to prevent a mosquito bite. This is particularly important if you are in areas where the diseases that are present have no vaccination as a prevention.
- Wear light coloured clothing - this is because the insects are thought to be attracted by darker colours.
- Clothing should cover as much of your body as possible and also wear a hat. Mosquitoes can get through some fabrics, but clothing will still significantly reduce the risk of being bitten.
- Use insect repellents - but take care as there are certain factors that can reduce the repellents ability to work. For example wearing too much sun screen, swimming, sweat, rain and high temperatures. When going to heavily infested areas where endemic diseases are present, it's best to use a repellent that has been scientifically tested. However, in order for them to work properly they have to be used exactly as stated in the instructions.
- There are many 'home-grown' or 'natural' repellents being sold to prevent mosquito bites. While some may be beneficial, there is as yet no scientific proof that they work. If you do have a method that you know has worked then by all means stick with it. For example some of the natural oils such as - cedar, rosemary, castor, lemon grass, clove and others, do help to repel mosquitoes but they have to be applied very regularly and in stronger doses than those manufactured by chemists.
- Some people - perhaps due to body chemistry, perfumes etc., seem to attract mosquitoes more than others. If you feel that you do attract them then be extra vigilant about protection. There are also many myths out there such as eating a banana attracts mosquitoes, or that vitamin B12, garlic and so on keeps them away - they are all false.
- Mosquitoes tend to be most active around dusk and dawn. Try to do any outdoor activities away from these times and/or take extra precautions.
- Dual purpose creams and lotions that have both sunscreen and insect repellent in them should be avoided. The problem is that sun screen usually needs to be applied in quite large amounts, but most insect repellents should only be applied sparingly. Research has shown that using two separate preparations is usually best.
- Try to avoid areas where mosquitoes breed such as swampy areas, standing water etc.
- Always use a mosquito net at night when sleeping. Ensure that all insect screens on doors and windows are in good order.
- Some plug-in devices containing insecticide have shown to be quite affective against mosquitoes.
- Research carried out in the USA showed that although bug-zappers do kill some mosquitoes they are not that effective in controlling their numbers. In addition, it was found that other insects who help to keep mosquito numbers under control were more likely to be killed by these devices.
I hope that this hub will be of some use to you if you live in or are travelling to mosquito zones. If you use common sense and take precautions then there is no need for the deadly mosquito to spoil having a good time.
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