Mite

Class: Arachnida

Sub-class: Acari

Phylum: Arthropoda

A mite is a microscopic organism measuring less than a millimeter. There are about 48000 species of mites that have been identified to date, and it is speculated that there are a million more of them yet to be discovered. Belonging to the same class as spiders, that is Arachnida, mites also have a few similar functions. However, these microorganisms pose threat to man and cause various issues like itching, scabies, acariasis, etc. There are several types of mites, and mite meaning is an umbrella term for all of them.

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Image: A mite insect 

Physical Description of Mites

A mite insect has a body measuring less than one millimeter or 0.04 inches. These organisms have eight legs like the other species of Arachnida. The body of a mite has a structure dedicated to feeding. This part of the body may be considered as its head and is termed a gnathosoma. Some species of mites are capable of tracheal breathing, that is, they breathe through their air tubes, whereas, in others, respiration occurs through the skin.

Types of Mites

Mites can be classified according to their orders and species and based on their functions. The mites scientific names are also interesting to learn. Mite meaning covers various types of mite species, of which seven different kinds of mites are discussed below. 

• Clover Mites:

 The clover mites barely bring along any diseases, however, still they are a cause of alarm for humans. These mites occur in several colours like green, red, or brown. When clover mites invade a house, they do not bite any human but attack the food storage. The time of the year when these mites actively invade food storage is winter. These microorganisms seek shelter and nutrition in the same way as any other organism does in the winter. The female clover mites are capable of laying eggs, without fertilization. These mites feed on various items, such as grasses, clover, plants, fruit trees, ivy, etc.

• Scabies Mites:

This category of mites inflict infections in mammals. These mites transmit scabies infection among humans from animals. The infection so caused is contagious and gets transmitted from one person to another through direct contact. Scabies mites have specific host species among animals and humans. They dig a burrow just under the skin and lay their eggs right in that tunnel-like burrow. It becomes quite painful for the host when the scabies eggs hatch and the larvae aggravate the irritation by burrowing deeper into the skin layers. Scabies mites are extremely contagious, however, their life cycle does not extend beyond 10 to 17 days.

• Itch Mites:

These are tiny mites and do not survive indoors neither can they live on humans. Mostly humans develop red rashes or marks due to the itch mites on exposure to hay, grass, seeds, leaves, or any other objects that these mites can survive on. Itch mites infest insects, however, they do not transmit the infection to any humans. On exposure to the objects on which these mites have grown, humans can develop itchy red patches.

• Bird and Rodent Mites:

These mites rarely bite humans and mostly attack birds and rodents. There are three types of rodent and bird mites that can impact humans. The tropical rat mites, spiny rat mites, and the house mouse mites. Unlike the itchy mites, the bite of a tropical rat mite can be painful and leaves the bitten site inflicted with itching and irritation. The bird mites mostly bite the pigeons, sparrows, chickens, and starlings. Bird mites like the chicken mites and the Northern Fowl mites may bite humans at times. The former thrives in the cracks and crevices close to a bird’s nest, while the latter readily survives without any host for nearly a month.

• House Dust Mites:

The house dust mites are considered to be among the potent and common indoor allergens. These mites induce dust allergy in humans and can trigger asthma attacks. However, these mites do not cause any skin irritation, neither do they live on any human body. They thrive on furniture, mattresses, pillows, or floor carpetings. Also, they feed on the dead flakes of human or animal skin that fall off on the floor. 

• Chiggers:

Chigger mites mostly survive in the soil and are more commonly found in rural areas. These mites tend to attack humans, reptiles, birds, by sensing the streams of carbon dioxide exhaled by them. On detecting a host, the chigger mites move towards their host through soil or vegetation. They get onto the host by waving their front limbs. These mites secrete skin-digesting saliva that liquefies the host’s skin and thus feed on the skin. If not checked in the first place, these mites can lead to inflammation of the bitten area.  

Behaviour of Mites

Now that we know ‘what are mites’ and the types of mites, we will learn about the behaviour of mites and how it varies from species to species. Some species live under the soil, some live on the skin of animals and humans, and some live in the dried dead leaves, while some decompose the organic matter.  

Habitat and Distribution of Mites

Each species of mites can thrive in different habitats. Some mites live in soil, some live in saltwater or freshwater ecosystems, while others live on the skin of mammals or on the feathers of birds. Some mites live on plants or trees by parasitizing the host. Also, some species of mites live in the nests of birds. Mites do not exhibit socialization, however, occur in congregations on the same host or on the same site.

Mites are present all across the world, and as per the research, almost a million species of mites are yet to be identified by humans. The distribution of a particular species of mites depends upon the type of habitat and mode of nutrition required by it. Mites are present even in Antarctica.  

Diet of Mites

The dietary habits vary for each species of mites. Those species of mites feed on feathers, dead skin, or the blood of mammals and birds. These are parasitic mites on humans. There are some rare species of mites that feed on even smaller microorganisms and happen to have a predatory mode of lifestyle. Also, certain mite species live on the dead and decaying matter and happen to have decomposer diets. These mites break the dead and decaying matter into simpler substances.  

Reproduction in Mites

Mites lay eggs for multiplying their population. For a few species, fertilization is not required for a female mite to lay eggs. However, in several species, a spermatophore is transmitted from the male mite to the female mite. After fertilization, the female mite lays her eggs. After the eggs are hatched, the larvae come out of its shell and grow up into adult mites.

The following is the life cycle of scabies mites.

Step 1: In these mites, the metamorphosis is not completed. Female scabies selects a site on their body where the skin is thinnest, as that of the skin between fingers and wrists. She creates a tunnel into the skin and lays about 30 eggs, at 2 to 3 eggs a day. 

Step 2: The eggs start hatching within 3-4 days of time and the larvae are 6-legged. These larvae move out of the tunnel-like burrow and reach the surface. They take about 3 days to develop into nymphs.

Step 3: The nymphs take about 6 to 8 days to transform into adult mites.

Step 4: It takes a period of 14 days to 31 days for the scabies mites to complete a life cycle from egg to egg. A female scabies mite can survive for a couple of months on humans and for 7 days to 10 days without any host.   

Control Measures for Mites

It is highly important to curb the spread of mites for maintaining a healthy lifestyle. There are certain chemicals that help in keeping the mites away from home as well as from the skin. Scabies mites can be controlled by the use of benzyl benzoate and Mitigal. 25% of benzyl benzoate can be highly effective for curbing sarcopidae. It can be applied downwards through the neck with the help of a brush and it will take at least 5 to 10 minutes to dry. This has to be repeated at an interval of 12 hours for the best results. The other one, mitigal is a sulphur ointment and has to be applied in the same manner downwards from the neck. Applying it once is mostly effective. 

Mites are to be kept away from furniture, food items, pillows, and plants so that no unwanted skin irritation or breathing problems come up. Maintaining a clean household and less exposure to the wild bushes or grass can help us stay away from mites.