Find out how to identify and treat flea bites along with the diseases you can catch.
Biting insects feed on humans and animals by piercing skin to tap into a blood vessel. They actively seek a food source by using their various senses such as heat, smell and sight to find a suitable host. Some insects make a quick feed and leave while others prefer to find hidden areas of the body to stay till they are gorged and can only drop off when they are swollen with blood.
Find out how to identify and treat flea bites along with the diseases you can catch.
Learn all about mosquito bites from indentifying and treating them to the diseases mosquitoe bites can cause.
Bed bugs are on the rise again. Find out how to identifying and treat bites from bed bugs.
Whichever way they find a host and feed, however, biting insects can cause itching, inflammation, painful welts and in addition can transmit many serious diseases that affect millions of people across the world.
Find out which fly species bite, and how to treat and identify them as well as how to prevent bites.
Learn about the different types on lice, how to treat and identify lice bites as well as the diseases they spread.
How can I prevent tick bites? All the information you need on removal, prevention & treatment of tick bites.
Bites itch because your body reacts to the saliva injected by the insect while it is biting you.
Biting insects have a complex mouth structure that varies between species. It can include a needle-like part that pierces the skin and other parts that are serrated and saw through the flesh to find a blood vessel.
They also have a food canal to suck up blood and a canal that injects saliva containing anticoagulant and anaesthetic. The anticoagulant keeps the blood liquid to keep it flowing and the anaesthetic stops you from feeling the bite so you don’t disturb the feeding insect.
The body’s immune system recognises the foreign material injected into the bite and produces histamine as a defence mechanism. This causes localised inflammation and itching.
a — antennae
c — compound eye
lb — labium
lr — labrum
md — mandibles
mx — maxillae
hp — hypopharynx
Source: Wikimedia commons: Xavier Vázquez.
People’s reactions to bites can vary greatly depending on the sensitivity of their immune system and whether they have been bitten before.
It can take hours or days for itching or redness to occur after being bitten, making it difficult to tell what bit you. In this case you will need other identifying factors to tell the source of the bite.
Fleas are wingless insects that are about 3-4mm long when adult. They are very agile and especially good at jumping.
As a ratio of their size, fleas are one of the longest jumpers of any animal. They can quickly spread widely once inside a building.
There are several types of flea that affect humans, pets and animals and are common in the human environment. They tend to prefer a particular animal host, but will still bite to see if the host is suitable before dropping off.
Common animals that can bring fleas into contact with humans include:
See descriptions of the various species on the Flea Species page.
Flea bites look a lot like other insect bites, but there are, however, a few key characteristics which separate them apart.
How to identify flea bites:
How to treat flea bites:
1. Do not scratch/itch the bite. This could lead to bigger problems.
2. Wash the bites with soap and warm water.
3. Apply an antiseptic spray or lotion to the area to reduce risk of infection.
4. Apply an icepack to the area to help reduce the swelling.
5. Take an antihistamine to help stop the itching.
There are over 3,500 known species of mosquito worldwide and a large number of these transmit diseases that affect more than 700 million people each year, causing at least two million deaths.
Only the female mosquitoes need a blood meal, having the specialised mouth parts that can penetrate animal skin, though they can also feed on sweet plant juices.
Male mosquito mouth parts are adapted only to feed on nectar and plant juices and cannot penetrate skin. It is the females that transmit diseases to humans and animals.
The female mosquito finds a host by sensing carbon dioxide in breath, perspiration and body odours, and tends to feed in the evening and night time, though there are notable exceptions.
Mosquito bites are characterised by itchy red bumps on the skin, with varying degrees of swelling, depending on the person’s immune response.
How to prevent mosquito bites:
How to treat mosquito bites
Mosquito bites can be treated with some simple measures:
1. Clean the bite area with soap and water: this is the most important treatment for a mosquito bite.
2. Use a cold compress: swelling can be reduced immediately after a bite by covering it with a cold compress such as ice in a cloth (but do not hold ice directly on the skin).
3. Take anti-histamines: itchiness and swelling can be relieved with antihistamine creams. Oral anti-histamine can also help if you have multiple bites.
4. Do not scratch: avoid scratching as this will increase the itching and could lead to the bite becoming infected.
One of the main concerns around mosquito bites, is their ability to spread the following diseases:
Fortunately they are not present in New Zealand.
You are most likely to pick up bed bugs from a hotel, where they can crawl into luggage and clothing. They can also catch a ride in bedding and furniture and spread through buildings by crawling through holes in walls, such as for electrical wiring, or along pipe work.
Bed bugs tend to feed at night but will search for a host at any time if they are starved. They find a host through an array of sensors that can detect warmth, carbon dioxide and body odours.
Bed bugs feed for only 5-10 minutes until they become engorged with blood, if not disturbed and may spend less than 20 minutes on a host. After feeding, they return to their shelter.
How to spot bed bug bites:
How to treat bed bug bites
Bed bugs do not carry diseases so the only treatment needed is to stop itching and rarely for inflammation. If the bites develop into very itchy bumps, general products available from a pharmacy to stop itching are suitable. For inflammation it is best to see a doctor who can prescribe the most suitable treatment. Many people do not react to bed bug bites so do not need any treatment.
How to prevent bed bug bites
If you are worried about bringing back bed bugs from your travels, then follow these steps to prevent bed bugs from entering your home and feeding upon you at night:
Worried about bed bugs in your hotel or dorm? Follow these steps to prevent them from biting your guests:
It is important to note that not all flies bite, some go about their day to day lives without the need to feast on humans. However there are a few fly species which rely on our blood to survive, these are:
How to treat fly bites:
1. Wash the bite with soap and warm water.
2. Use and apply either antiseptic cream or spray to the area after washing.
3. Apply ice to the bite for 15 minutes, several times a day.
4. Avoid scratching so you don’t break the skin and cause and infection.
The bites of some flies such as horse flies can bleed. In this case a simple plaster applied after the bite has been washed would help. If the bleeding doesn’t stop on its own, you should see a doctor.
How to prevent fly bites:
The term midge and gnat is a very general term for a wide range of flies, including the Sand fly and Black fly. Most are aquatic during the larval stage.
Lice cannot jump or fly but can crawl from person to person in close contact. Head lice commonly affect children, but anyone with hair can catch them.
Head lice are considered harmless as they are not known to carry any disease and are regarded more as a cosmetic problem. They do cause itching of the scalp and secondary infections can result from scratching.
Detecting head lice
They are commonly found in the hair behind the ears and at the nape of the neck.
The remains of the white egg cases can also be seen attached to hairs.
The lice can be combed out of the hair onto a piece of white paper using a special nit comb that has very closely-spaced teeth to trap the lice.
Treating head lice
Repeated use of a nit comb can remove the lice, but larger infestation may only be effectively removed with medicated shampoos or lotions available from pharmacies. These contain insecticide so should be used carefully, especially on children.
The body louse (Pediculus humanus humanus) is indistinguishable from the head louse, but lives mainly in clothing, so the two types do not interbreed under normal conditions.
They are thought to have evolved from head lice around 100,000 years ago, which is about the time when humans invented clothing.
Prevention and treatment is to wash infected clothing at high temperature or destroy it.
The body louse can spread the rickettisal diseases Epidemic typhus (Rickettsia prowazekii) and Murine typhus (Rickettsia typhi). Epidemic typhus has been responsible for millions of deaths throughout history especially in time of war among soldiers and prisoners.
How Typhus spreads
The louse picks up the disease by feeding on an infected person then when moving to another person excretes the organism in its faeces. The bacteria infect the host through the bite wound when the faeces and squashed lice are rubbed over the skin. It can also be inhaled in air-borne particles or enter the body rough the mucous membranes of the mouth and eyes.
The body louse was the principle means of the spread of the bacteria B. Quintana, the cause of trench fever during the First World War. It infected a large proportion of troops on both sides. In recent times it has been recorded worldwide: in Europe, North America, Africa, and China. Other biting insects can also spread the disease.
The crab louse (Pthirus pubis) feeds exclusively on blood and is only found on humans. It is distinct from the other two types of human louse in appearance, having a rounder and shorter body. It is usually found in pubic hair or other coarse hair such as eye lashes, beards and moustaches. It is mainly spread by close contact, sexual activity and shared use of towels, clothing and beds.
Nymphs and adult of the triatomine bug Rhodnius prolixus.
Source: Wikimedia Commons: Thierry Heger
An adult bug and a nymph with clear defecation marks on the wall, in a house in Mexico.
Source: WHO (Chagas disease campaign), Isaias Montilla.
The group is easily distinguished from insects, which have six legs, three body sections (head, thorax and abdomen) and one pair of antennae. They are both in the Arthropod phylum, however, which consists of animals having an exoskeleton.
The arachnids have many members that can be pests of humans: the ticks, mites and spiders.
Ticks inhabit areas with long grass or heavy vegetation. They can sense a host by detecting breath, body odours, body heat, moisture and vibrations through a sensory organ in the first pair of legs.
Ticks do not seek a host but lie in wait, climbing up grass or onto the edge of leaves and hold up their front pair of legs to wait for a host to pass and latch onto — a posture called ‘questing’. They then crawl around the host looking for their preferred site to feed from, such as soft skin.
A tick on a blade of grass with forelegs extended in the questing position.
Source: Wikimedia Commons: Mcvoorhis
How to prevent tick bites
In areas of known infestation you can take some measures to reduce the chance of tick infestation:
It is important to remove a tick properly so that you do not leave mouth parts behind in the skin, squeeze body fluid into the bite or cause it to regurgitate into the bite, which will increase the chance of infection.
How to remove ticks:
1. Wear gloves or using a cloth or tissue to prevent catching an infection from contact with the tick;
2. Use a pair of fine-tipped tweezers or commercial tick removal tool;
3. Grab the tick as close as possible to the skin, to include the mouth parts if possible;
4. Gently pull the tick straight out until the mouth parts are removed;
5. Wash your hands with soap and water;
6. Clean the bite area with soap and water or an antiseptic;
7. Seek medical attention if you cannot remove all of the tick from the skin.
Ticks can carry a variety of viruses, bacteria and protozoa, including several at the same time, which can make diagnosis and treatment difficult.
Mites are closely related to ticks. There are nearly 50,000 known species, mostly microscopic, occupying a very diverse range of habitats. Many are pests of plants and animals such as bees and birds, but very few affect humans.
The house dust mite does not feed directly on humans but on shed skin particles and pet dander. The shed skins and faeces can cause allergic reactions in some people, similar to hay fever, asthma and eczema.
The scabies mite, Sarcoptes scabiei, is a parasitic mite about 0.5mm long that burrows into the outer layer of skin to feed on skin cells. It lays 10-25 eggs that hatch and emerge from the skin after 3-4 days to travel to another part of the body and repeat the cycle.
The infection results in itching caused by the body’s reaction to secretions from the mites. This can take up to eight weeks to appear.
Scabies is highly contagious. People living in the same household are likely to become infected easily.
The most common treatments for scabies are the pesticides permethrin, malathion and lindane. However, these can have side effects and should be used with advice from a medical professional.
Rickettsialpox is caused by the bacteria Rickettsia akari, which can be carried by house-mouse mites. They will seek new hosts, including humans, when the mice die off naturally or as a result of pest control. Infection is transmitted by the bite of the mite.
Rickettsialpox is regarded as a mild disease that takes 2-3 weeks to recover from. The first symptom is a bump around the bite that appears about a week after the bite, which turns into black crusty scab.