The Anopheles is a genus of mosquito, and is best known for being the primary vector of malaria in humans and heartworm in dogs. They are found nearly worldwide (except Antarctica) with over 450 different species in this one genus, however it is known that only 30 to 40 species transmit malaria, depending on the region and environmental conditions. The two most common malaria vectors in Africa, A. gambiae and A. funestus, are strongly anthropophilic, preferring to feed on human blood. This makes them incredibly efficient in the transmission of the disease and makes the elimination of malaria particularly difficult. This map from the US CDC shows the global distribution of dominant or potentially important malaria vectors. Despite being a relatively old resource, it highlights the severity of the problem.
It is only the females Anopheles that bite humans as they require a blood meal for the development of eggs. The males feed mainly on nectar and other sugar sources. The females typically live no more than 2 weeks in nature, but can live up to a month, and even longer in captivity.
Most Anopheles mosquitoes are active either at dawn, dusk or at night, and can be distinguished from other mosquitoes in several ways. Their palps are as long as the proboscis, they have blocks of black and white scales on their wings, and their typical resting position is with their abdomens sticking up in the air rather than parallel to the surface on which they are resting.
The Culex is a very diverse genus of mosquito, and is also known as the common house mosquito. It can be found all over the world from the tropics to cool temperate regions, although it is not found in the extreme northern latitudes. It is the most common genus of mosquito found in some of the main cities in the US.
They vary in size depending on the genus with most adult Culex measuring between 4mm and 10mm. They have short palps in comparison to the Anopheles genus, and tend to keep their bodies parallel to a surface with the head bent down. They are mainly brown in colour but can have transverse white lines on the upper surface of their abdomen. They also have a blunt tip on the abdomen, and the wings are clear and transparent.
They are typically weak fliers and only live up to 2 weeks. Much like the Anopheles mosquitoes, the males feed solely on plant nectar, while the females need blood meals for the development of eggs. They typically get their blood meals from birds not humans, and is not considered as much of a threat to human life as the Anopheles and Aedes mosquitoes. The eggs are laid on surface of standing water where there is no plant life such as puddles, buckets and old tyres.
They are painful and persistent biters who prefer to attack at dusk and after dark, and they readily enter houses for blood meals.
Culex are the primary vectors of West Nile virus, and transmit other important diseases such as filariasis, Japanese encephalitis, St. Louis encephalitis, Murray Valley encephalitis, Red River viruses and Rift Valley fever.
The Aedes mosquito is a genus of mosquitoes originally found in tropical and subtropical zones, but now found on all continents except Antarctica. Many of the species have been able to expand their geographic distribution due to international trade and have been inadvertently spread across the world by humans.
They are visually very distinctive compared to the other genus of mosquito, mainly due to the black and white markings on their legs and bodies. The average life span in nature is about 2 weeks, but they can lay about 3 times in this lifetime with approximately 100 eggs each time. Their eggs withstand very dry conditions and lie dormant for up to 9 months until the right conditions for them to hatch.
They are opportunistic and aggressive biters, whose feeding peaks at dawn and dusk. However, some types of Aedes (such as Aedes aegypti) are capable of breeding indoors and therefore bite throughout the day.
Members of the Aedes genus are known vectors of many diseases, most notably dengue fever, yellow fever, West Nile fever, Chikungunya, eastern equine encephalitis, and more recently the Zika virus.
Ticks are arthropods and members of the arachnid family, related to scorpions and spiders. They are many different species and are widely distributed around the world, each preferring to feed on the blood of different animals. They thrive in countries with warm, humid climates because of the higher moisture content in the air which is good for their development. They can typically be found in woodlands, moorlands, rough pastures, forests and urban parks. They can also sometimes be found in gardens, especially those with shady shrubberies or deep vegetation and a strong local wildlife population.
They are very small, almost invisible to naked eye but once fed they grow considerably. The colour varies by species, sex and whether they have fed or not. Unfed they are a reddish brown or sometimes black. Once fed they can be pink, purple or a dark red. They have a typical life span of 2 years.
The most common tick species find their hosts using an ambush strategy. Positioned on a plant stem or leaf with their front legs outstretched, they wait for the host to come close enough to get on. They are not able to fly or jump so use their keen senses to identify a host. They sense body odours, CO2 from the breath, body heat, shadows and vibrations. Once attached they will feed on the host’s blood for several days, then drop off once gorged. They often go unnoticed due to anaesthetic properties secreted in their saliva.
They are a vector of a number of diseases, including lyme disease, Colorado tick fever, Rocky Mountain spotted fever, African tick bite fever, tularemia, tick-borne relapsing fever, babesiosis, ehrlichiosis, tick paralysis, and tick-borne meningoencephalitis.
There are over 4,000 species of biting midges, ranging in size from 1-3mm in length. The distribution of midges in the genus Culicoides is world-wide. They are found in marshy habitats, as well as mountainous regions, depending upon species. One of the areas most renowned for human feeding midges (typically Culicoides impuncatus) is the Highlands of Scotland, where midges can cause discomfort to tourists and disruption to outdoor industry, including agriculture and forestry.
Both males and females feed on nectar, but like many insects in this section, the females need blood for their eggs to mature. They only live for a few weeks under natural conditions but can lay up to 100 eggs per blood meal, depending on the species.
Biting midges are a nuisance to anyone who enjoys being outdoors and their bites are irritating and painful. They are most active in the early morning and evening, but can remain active all day when it is cloudy with little wind. In Central and South America, western and central Africa, and some Caribbean islands, biting midges are more than just a nuisance. They are the vectors of filarial worms which can cause skin infections and lesions. Biting midges are often incorrectly referred to as Sand Flies.
Sand Flies are members of the Phlebotominae subfamily, which includes many genera of blood-feeding flies. They can be found in a wide range of habitats between latitude 50°N and 40°S (excluding New Zealand and the Pacific Islands), varying by species. They are often confused with other types of biting flies because the common name "sand fly" is also used generically when referring to other genera of biting flies. Sand Flies are small (2-3mm in length) and brownish in colour in the daylight, but their bodies are densely covered in oily hairs which give the insects a whitish, moth-like appearance when illuminated. The most distinctive feature of the sand fly is that they hold their wings in a raised 'V' while at rest, their wings are never closed or laid flat across the body.
Sand Flies are nocturnal feeders, with only the female responsible for biting and then sucking the blood of their host. The bites from a sand fly are painful and leave large itchy bumps. They tend to last longer than and are often several times itchier, than mosquito bites. They find shelter during the day in dark, humid places such as tree holes or under rocks. Sand Flies have very weak direct flight abilities, so they do not hover around their host, thereby reducing the perceived nuisance of the species. Of the 700 species of sand fly, 70 are considered to be vectors of diseases including leishmaniasis, bartonellosis and pappataci fever.
Land Leeches are blood sucking ectoparasites that feed on mammals. They are common in tropical and sub-tropical rainforests. Leeches are not known to spread any diseases but their bites cause haemorrhaging that is difficult to stop. As wounds stop bleeding, localised inflammation and itching is common at the bite site. Most land leech species remain on the ground while awaiting a host then attach themselves to a person’s footwear and climb upwards. Once they are attached to a host, they are not easily removed. Some species do climb to higher vegetation during wet weather to await a host.
There are two primary methods of protection against Leeches, leech socks and repellents. Leeches have damp skin, making them very sensitive to various substances and chemicals. Repellents in leech infested areas are often applied to shoes, boots and to trousers tucked into socks from the ankle to the knee (with application to areas above the knee in areas where climbing land Leeches are prevalent).
Black Flies are small, ranging in size from 5 to 15mm, and black or grey in colour. They breed exclusively in running water. Because of their ability to filter dissolved organic matter and make it available to other species in the food chain, they are a keystone species in the ecology of water bodies. However, this trait also makes Black Flies very susceptible to both organic and inorganic pollution in our waterways, making them good indicator species for the ecological condition of fresh water streams and rivers.
Black Fly species vary in their preferred host for a blood meal, some preferring humans and others preferring birds and other mammals. Black Fly bites can be very painful, with itching and swelling generally occurring at the bite site. Intense feedings can cause a condition known as Black Fly Fever, with headache, nausea, fever, swollen lymph nodes and aching joints being the most common symptoms. In certain areas of the world, such as Africa and mountainous regions of South and Central America, Black Flies can transmit a parasitic nematode worm that can infect humans and cause a disease known as onchocerciasis or river blindness.
Black Flies are active only during the day, with peak activity around 9:00 to 11:00 AM and again from 4:00 to 7:00pm. They tend to be most active on humid, cloudy days and just before storms.
The Stable Fly (Stomoxys spp.) also called the barn fly, biting house fly, dog fly or power mower fly, is lighter in colour than the common house fly and somewhat smaller in size, generally about 5-7mm in length. Unlike a house fly, its mouth parts have biting structures, rather than those built for sponging. Both male and female Stable Flies feed predominately on animals (mostly horses and cattle). However, they are known to bite humans in the absence of an animal host.
Stable Flies can be found worldwide wherever suitable weather and feeding conditions are present. Their feeding increases during warm weather, and decreases during rainy weather. They are daytime feeders, locating their host by sight and feeding from several hosts until full. After feeding Stable Flies are very sluggish and rest nearby their host in a sunny spot.
The Stable Fly is reported to be a possible vector of trypanosoma evansi, t.brucei, t. cazalboui, t. pecaudia, brucellosis, swine erysipelcs, equine Infectious anemia, African horse sickness, fowlpox, and bacillus anthracis, which causes anthrax in domestic animals and humans. The accumulation of Stable Fly bites can also cause anaemia and weight loss in livestock, a significant loss in milk production in dairy cattle and destroy cattle hides, causing economic losses in livestock related industries.
Mosquito bite prevention
Mosquito bite prevention
Keep covered up
Most mosquitoes bite between dusk and dawn. Avoid exposing your skin by wearing long sleeved shirts and trousers. Aedes mosquitoes which transmit dengue and yellow fever are mainly active during the day with their peak biting times shortly after sunrise and just before sunset. To avoid being bitten by these daytime biters avoid outdoor shady conditions and sleep under a mosquito net if you take a siesta.
Use effective insect repellent
If your skin is exposed then it is important to use a safe and effective insect repellent on all areas of exposed skin.
Use a mosquito net at night
Mosquito nets provide very good protection especially when impregnated with the residual insecticide permethrin. Permethrin is poorly absorbed by the skin and has a low mammalian toxicity. There are a number of different styles of mosquito net and you should choose the one most suitable for where you are.
Sleeping in a room with air-conditioning will discourage mosquitoes.
Use a plug-in insecticide vaporiser
Use a knockdown spray (any fly spray will do) to clear the room of mosquitoes. Plug-in insecticide vaporisers are very effective for overnight protection as long as the room is relatively free from draughts. The vaporisers consist of a heating pad onto which an insecticide soaked tablet is placed. The insecticide gradually vaporises throughout the night killing any mosquitoes that get into the room.
Spray mosquito breeding grounds
If you are staying for long periods in areas where mosquitoes are a problem, then remember that they breed in stagnant water. Mosquitoes lay eggs in as little as a quarter inch of standing water. A good mosquito bite prevention method is to ensure mosquito breeding areas within 500 yards of your accommodation are regularly sprayed or eliminated.
Tick bite prevention
Tick bite prevention
Tick bites spread Lyme disease in the UK and abroad. There is currently no vaccine against Lyme disease so you must be aware that areas with ground cover, foliage and diverse wildlife can pose a risk of ticks. Ticks wait in long grass and vegetation in order to attach themselves to their victims or hosts as they brush past. Always try to stick to footpaths when you are walking, trying wherever possible to avoid the areas indicated above.
To prevent tick bites use an insect repellent and keep covered up. Wear light coloured clothing with long sleeves and trousers. Ensuring that trouser legs are tucked into your socks will also help. If you are in areas known to have ticks, long hair should covered or tied up.
After being outside in tick prone areas be sure to check your body, pets and clothing for ticks, take a shower and wash you hair. You could also wash your clothes and put them on a high heat cycle in the tumble dryer to ensure that no ticks survive. Make sure that you carry a tick remover, or fine pointed tweezers, so you can quickly remove ticks and reduce the chance of disease transmission.
Furthermore, ticks rapidly loose moisture and as a result can't survive in low humidity. Staying in areas with lots of sun exposure will help reduce the chance of tick bites.
Ensure that you keep all pets that have been outside off the furniture, especially in the bedroom.
Midge bite prevention
Midge bite prevention
Midges are tiny swarming insects that are common in the Scottish Highlands during the summer months. They are normally active at low light so are typically seen around sunset. Bites from midges do not transmit disease but can make life almost unbearable. Citriodiol® based repellents will help stop midges from biting but not from swarming around you. Covering skin with clothing will also help prevent being bitten as midges can't bite through material, and light clothing is preferable to dark. They can get under clothes so you could avoid them with more protective methods such as anti-midge hats, midge body suits and midge netting (smaller than mosquito nets) to cover tent entrances.
It is advisable to note the periods and conditions when midges are most active, and avoid being outside during these times. Calm, still windless summer evenings are when midges will be most active. They struggle in windy conditions and tend to stop flying. It is also important to try to avoid wet, boggy areas which are common breeding sites for midges. As midges are less common at heights (above 700m), try to get to higher ground.