The house dust mite Name : Nessma Magdy Abd EL-Rahman Supervised by : Prof.Dr. Safia Saleh What is a dust mite?

They are too small to see with your eyes alone.  Under a microscope, they look like white bugs.  They have eight legs, so they are not insects, but arthropods, like spiders.

They live in house dust and feed on the dead skin cells that people regularly shed. What is a dust mite?

 Dust mites can survive in all climates and at most altitudes.

They thrive in warm environments, preferring those at 70°F (21°C) and 70 percent relative humidity y.

What is a dust mite allergy?

When you breathe in the waste products of dust mites, your immune system kicks into high gear, producing antibodies against the normally harmless substances. This overzealous immune response causes the symptoms associated with a dust mite allergy, such as sneezing and runny nose dust mite allergy?

The allergenic proteins responsible for causing symptoms are contained within the mites themselves (alive or dead), their shed skins, and especially in their feces.

Routine human activity such as housecleaning, walking or playing on carpeting, or making the bed, causes the tiny fecal particles to become airborne and inhaled dust mite allergy?

Seven different dust mite species found living in an old mattress

 By cutting core sections from an old box- spring mattress a scientist found seven different species of mite infestations.  Among the species identified were house dust mites, storage mites and one follicle mite, all of which are known to cause disease in humans 95% of the mites found were within 1.5 cm of the top of the mattress. The area of the old mattress investigated was from half of a double bed; sectioned from the top and bottom.

The research criteria was to investigate population abundance and how this type of mite-sampling may contribute to future house dust mite research.

 The study was published in 1995 and funded by Asthma UK. Results:

The dust mite species identified were Dermatophagoides pteronyssinus, known as the house dust mite and most dominant of the populations harvested (95%), Euroglyphus maynei (3%) Cheyletus tenuipilis (2%) and Tarsonemus (unidentified). Storage mites were Lepidoglyphus destructor and Acarus siro. The follicle mite was Demodex follicorum The main species are identified as

Dermatophagoides farinae (American house dust mite)

Dermatophagoides microceras

Dermatophagoides pteronyssinus (European house dust mite)

Euroglyphus maynei (Mayne's house dust mite)

House dust mite

• Scientific classification • Kingdom: Animalia • Phylum:Arthropoda • Class:Arachnida • Subclass:Acarina • Order:Acariformes • Family:Pyroglyphidae • Genus:Dermatophagoides • Binomial name • Dermatophagoides farinae Hughes, Dermatophagoides microceras, Dermatophagoides pteronyssinus Binomial name Euroglyphus maynei

• Scientific classification • Kingdom:Animalia • Phylum:Arthropoda • Class:Arachnida • Subclass:Acarina • Order: Acariformes • Family:Pyroglyphidae • Genus:Euroglyphus Biology and Habits

House dust mites have specific environmental requirements for their development.

 The mites tend to be most numerous in warm homes with high humidity. Biology and Habits

 Optimum conditions for growth and development are around 75-80 degrees F and 70-80 percent relative humidity.

House dust mites absorb and lose moisture through their skin, and are very vulnerable to dehydration. Consequently, humidity levels within the home have a significant effect on survival. Biology and Habits

Dust mites cannot survive well at relative humidities below 50 percent.

 Although mite populations tend to be low in dry climates, most homes throughout the United States are capable of supporting dust mites. House dust mites and their allergenic particles are present within homes year round,

 but people tend to have fewer symptoms during the summer, perhaps because they spend more time outdoors. Biology and Habits

Food is seldom a problem for house dust mites.

Their primary food is skin scales (dander) contained in house dust.

People and pets regularly shed small flakes of skin from their bodies as the skin continually renews itself. Biology and Habits

Since the greatest fallout occurs in areas of human and pet activity,

 the mites tend to be most numerous in beds, overstuffed sofas and chairs, and adjacent carpeted areas. Biology and Habits

Relative humidity also tends to be higher in these areas,

 because people perspire and exhale water vapor where they sleep and lounge. Biology and Habits Mattresses,  sofas,  carpet, other soft furnishings trap accumulate dust, dander moisture, making them ideal microhabitats for mite development.

Life cycle

House dust mites go through five major life stages: 1. egg, 2. larva, 3. protonymph, 4. tritonymph 5. adult. Between life stages the mites molt, shedding their outer skin. Life cycle

When temperature and humidity are optimum, development from egg to adult takes about one month.

 Adults live approximately 1-2 months, and the females lay about 50 eggs Life cycle

two species that are the most common and are the main source of House Dust Mite allergen are : 1. Dermatophogoides farinae 2. and Dermatophadoides pteronyssinus from the family Pyroglyphidae. The life cycle of Dermatophagoides pteronyssinus consists of 5 stages: Life cycle

The adult mated female can lay 40 – 80 eggs in her lifetime.

 When the egg hatches a six legged larva emerges.

There are two nymphal stages that feed and moult before an eight legged adult is developed. Life cycle

The adult House Dust Mite has a mouth-like appendage but no eyes or antennae.

The duration of the cycle is usually one month but is dependent on : the climate, ideally 25°C and 75% relative humidity. Life cycle

An adult House Dust Mite can live for one to three months under favourable conditions The translucent body of a house dust mite is 300 µm – 400 µm in length and only visible under a microscope.

House Dust Mite faecal pellets range from 20 µm – 50 µm. Life cycle

 It is estimated that the House Dust Mite can produce 20 faecal pellets per day.

House Dust Mites are ~75% water by weight and therefore need to absorb water from the water vapour in the air making relative humidity a critical factor for survival.

Causes of dust mite allergies

An allergy is the immune system’s response to an unknown substance that’s not usually harmful to your body. These substances are called allergens.

They may include certain foods, pollens, and dust mites. Causes of dust mite allergies

People who are allergic to dust mites have bad reactions to the remnants of the bugs.

 These remnants include tiny mounds of feces and decaying bodies. Symptoms of a dust mite allergy

 runny or itchy nose  postnasal drip  itchy skin  congestion  sinus pressure (may cause facial pain)  itchy, watery, or red eyes  scratchy throat  cough  swollen, bluish-colored skin beneath the eyes  trouble sleeping Symptoms of a dust mite allergy

You may experience additional symptoms if you have asthma and are allergic to dust mites. These symptoms may include: chest pain or tightness difficulty breathing wheezing, coughing, or shortness of breath difficulty talking, severe asthma attack

Diagnosing dust mite allergies

Your allergist will use diagnostic tests to determine whether you have a dust mite allergy. The most common type of test is a skin-prick test.  During this test, the allergist will prick an area of your skin with a small extract of the allergen.

• . Your allergist will then wait about 15 minutes to see if your skin has any negative reactions. If you do have a reaction, you will likely develop a large bump around the pricked area of skin.  The area may also become red and itchy. A blood test is sometimes used instead of a skin test.

Note that a blood test can only screen for antibodies, so the results may not be as accurate

Dust mite allergy prevention Use allergen-proof bed covers on the mattress, box spring, and pillows. Zippered covers are best. Their tightly woven fabric prevents dust mites from getting into beds. Wash all bedding in hot water at least once a week. This includes sheets, pillowcases, blankets, and bed covers. Dry in a hot dryer or in natural sunlight during summer months. Dust mite allergy prevention

There are more ways to manage dust mites. Unlike with outside allergens such as pollen, you can keep dust mites under control with a few key steps: Use an air conditioner or dehumidifier to keep the relative humidity in your house between 30 and 50 percent Dust mite allergy prevention

 Purchase a high-efficiency particulate air (HEPA) filter.  Buy only washable stuffed toys, and wash them often. Keep stuffed toys off beds.  Dust frequently with either a damp or oiled towel or mop. This helps minimize the amount of dust and prevents it from accumulating. Dust mite allergy prevention

 Vacuum regularly using a vacuum cleaner with a HEPA filter. A person with a severe dust mite allergy should have someone else do this task.  Get rid of clutter where dust collects.  Clean curtains and upholstered furniture often.  Replace carpeting with wood, tile, linoleum, or vinyl flooring, if possible. Dust mite allergy prevention Treating a dust mite allergy

• antihistamines, such as Allegra or Claritin, can help relieve sneezing, runny nose, and itching • nasal corticosteroids, such as Flonase or Nasonex, can reduce inflammation while offering fewer side effects than their oral counterparts Treating a dust mite allergy

• decongestants, such as Sudafed or Afrin, can shrink tissues in nasal passages, making it easier to breathe. • medications that combine an antihistamine and decongestant, such as Actifed. Treating a dust mite allergy

• Other treatments that may provide relief include: • cromolyn sodium

• leukotriene modifiers such as Singulair, Accolate, or Zyflo

• immunotherapy, also known as allergy shots References http://www.airmidhealthgroup.com/resources-at- • airmidhealthgroup/articles/250-the-biology-of-house-dust- mites-and-dust-mite-allergies.html /http://www.futurity.org/house-dust-mites-flights-819392 • http://waynesword.palomar.edu/redmite7a.htm#dustmite • http://www.pestmall.com/blog/know-how/how-to-get-rid- • of-dust-mites http://entnemdept.ufl.edu/creatures/urban/house_dust_mi • te.htm http://www.aafa.org/page/dust-mite- allergy.aspx#life http://housedustmite.com/seven-different-dust-mite- • /species-found-living-in-an-old-mattress • References https://en.wikipedia.org/wiki/House_dust_mite • • "house dust mites - Dermatophagoides spp.". entnemdept.ufl.edu. • • https://entomology.ca.uky.edu/ef646 • References 'An 'in situ' coring technique for estimating the • population size of house dust mites in their natural habitat', D. B. Hay, Acarologia, t. XXXVI fasc. 4, 1995 Thank You