TICKS

INTRODUCTION

• Ticks are small arachnids in the order Parasitiformes.
• Along with mites, they constitute the subclass Acarina. 
• Ticks are ectoparasites (external parasites), living by hematophagy on the blood of mammals, birds, and sometimes reptiles and amphibians. 
• Ticks are vectors of a number of diseases, including Lyme disease, Q fever (rare; more commonly transmitted by infected excreta),Colorado tick fever, Rocky Mountain spotted fever, African tick bite fever, Crimean Congo hemorrhagic fever, tularemia, tick-borne relapsing fever, babesiosis, ehrlichiosis, and tick-borne meningoencephalitis, as well as bovine anaplasmosis and probably the Heartland virus.
• Some species, notably the Australian paralysis tick, are also intrinsically venomous and can cause paralysis.

Scientific classification

Kingdom:  Animalia

Phylum:  Arthropoda

Class: Arachnida

Subclass: Acari

Order: Parasitiformes

Leach, 1815

Suborder:   Ixodida

Superfamily: Ixodoidea

Leach, 1815

Families

Ixodidae – hard ticks

Argasidae – soft ticks

Nuttalliellidae

LIFE CYCLE

TYPE OF TICKS

SYMPTOMS OF TICKBORNES ILLNESS

Many tickborne diseases can have similar signs and symptoms. 

If you have been bitten by a tick and develop the symptoms below within a few weeks, a health care provider should evaluate the following before deciding on a course of treatment:

The most common symptoms of tick-related illnesses are:

-Fever/chills: With all tickborne diseases, patients can experience fever at varying degrees and time of onset.

-Aches and pains: Tickborne disease symptoms include headache, fatigue, and muscle aches. With Lyme disease you may also experience joint pain. The severity and time of onset of these symptoms can depend on the disease and the patient's personal tolerance level.

-Rash: Lyme disease, southern tick-associated rash illness (STARI), Rocky Mountain spotted fever (RMSF), ehrlichiosis, and tularemia can result in distinctive rashes:

• In Lyme disease, the rash may appear within 3-30 days, typically before the onset of fever. The Lyme disease rash is the first sign of infection and is usually a circular rash called erythema migrans or EM. 
• This rash occurs in approximately 70-80% of infected persons and begins at the site of a tick bite. It may be warm, but is not usually painful. 
• Some patients develop additional EM lesions in other areas of the body several days later.
• The rash of (STARI) is nearly identical to that of Lyme disease, with a red, expanding "bulls eye" lesion that develops around the site of a lone star tick bite. 
• Unlike Lyme disease, STARI has not been linked to any arthritic or neurologic symptoms.
• The rash seen with Rocky Mountain spotted fever (RMSF) varies greatly from person to person in appearance, location, and time of onset. About 10% of people with RMSF never develop a rash. 
• Most often, the rash begins 2-5 days after the onset of fever as small, flat, pink, non-itchy spots (macules) on the wrists, forearms, and ankles and spreads to the trunk.
•  It sometimes involves the palms and soles. 
• The red to purple, spotted (petechial) rash of RMSF is usually not seen until the sixth day or later after onset of symptoms and occurs in 35-60% of patients with the infection.
• In the most common form of tularemia, a skin ulcer appears at the site where the organism entered the body. 
• The ulcer is accompanied by swelling of regional lymph glands, usually in the armpit or groin.
• In about 30% of patients (and up to 60% of children), ehrlichiosis can cause a rash. 
• The appearance of the rash ranges from macular to maculopapular to petechial, and may appear after the onset of fever.
• Tickborne diseases can result in mild symptoms treatable at home to severe infections requiring hospitalization. 
• Although easily treated with antibiotics, these diseases can be difficult for physicians to diagnose. 
• However, early recognition and treatment of the infection decreases the risk of serious complications. 
• So see your doctor immediately if you have been bitten by a tick and experience any of the symptoms described here.

HOW IS A TICK REMOVED FROM THE SKIN?

The following is a step-by-step method that is suggested for safe and effective removal of all types of ticks. 

Web citations 2 and 3 show a diagram of how to place tweezers to remove a tick.

1. Wear hand protection such as gloves so you don't spread pathogens from the tick to your hands; use forceps or tweezers to grab the tick at skin level.
2. Grasp the tick firmly with the tweezers as close to the skin as possible without crushing the tick. Apply gentle pulling motion upward until the tick comes free. Twisting or turning the tick does not make removal easier because the mouthparts are barbed; in fact, such actions may break off the head and mouthparts, thereby increasing the chances for infection. The second web citation illustrates the proper removal of a tick.
3. Once the tick is removed, don't crush the tick because it may release pathogens. Consider keeping it in a tightly closed jar or taped to a piece of paper. Show the tick to the doctor if the person bitten becomes ill after the tick bite. Flush any removed ticks not kept for identification down the toilet or sink.
4. The area of the bite should leave a small crater or indentation where the head and mouthparts were embedded. If portions of the head or mouthparts remain, they may be removed by a doctor.
5. Thoroughly cleanse the bite area with soap and water or a mild disinfectant. Observe the area for several days for development of a reaction to the bite (rash or signs of infection). Apply antibiotic cream to the area as a precaution. Application of an antibiotic to the area may help prevent a local infection but usually does not affect the chance of developing diseases transmitted by the tick.
6. Wash hands thoroughly after handling any tick or instruments that touched a tick. Clean and disinfect any instruments that were 

HOW ARE BITES FROM TICKS PREVENTED?

The third web citation below has the CDC recommended methods (tips) for outdoor workers (and others) to avoid getting tick bites and is summarized here:

1. Avoid grassy areas and shrubs where ticks populations may be high and where they reside, waiting to grab a ride on a potential host.
2. Wear light-colored clothing so ticks can be easily seen, and brush them off.
3. Tuck pants into boots or socks to avoid ticks crawling up loose pant legs.
4. Apply insect repellant and use the brands designed to repel ticks. Follow label instructions. Avoid use of DEET-containing repellents on children. Carefully follow instructions and apply some repellents directly to skin and others to clothing. DEET-containing repellents with concentrations of 15% or less may be suitable for children. These should be carefully applied strictly following label directions. Repellents containing permethrins may be applied to clothing but not to skin. In areas that have a high tick population, DEET-containing repellents may need to be reapplied more frequently than for repelling mosquitoes. Follow the package label instructions carefully.
5. Promptly check yourself, others, and pets if exposed to areas where ticks are likely to be located.

REFERENCES : TICKS

MITES

INTRODUCTION

• Mites, along with ticks, are small arthropods belonging to the subclass Acari (also known as Acarina) and the class Arachnida. 
• The scientific discipline devoted to the study of ticks and mites is called acarology.
• In soil ecosystems, mites are favored by high organic matter content and by moist conditions, wherein they actively engage in the fragmentation and mixing of organic matter.

MOST COMMON SPIDER MITES

SCIENTIFIC CLASSIFICATION

Kingdom: Animalia

Phylum: Arthropoda

Subphylum: Chelicerata

Class: Arachnida

Subclass: Acari

Leach, 1817

Superorders

Acariformes

Parasitiformes

LIFE CYCLE

SYMPTOMS

DIVERSITY AND ECOLOGY

• Mites are among the most diverse and successful of all the invertebrate groups. 
• They have exploited an incredible array of habitats, and because of their small size (most are microscopic), go largely unnoticed. 
• Many live freely in the soil or water, but there are also a large number of species that live as parasites on plants, animals, and some that feed on mold.
• It is estimated that 48,200 species of mites have been described.
• Mites occupy a wide range of ecological niches. 
• For example, Oribatid mites are important decomposers and occur in many habitats. 
• They eat a wide variety of material including living and dead plant and fungal material, lichens and carrion; some are even predatory, though no species of Oribatida mite are parasites. 
• Many mites which have been well studied are parasitic on plants and animals. 
• One family of mites Pyroglyphidae, or nest mites, live primarily in the nests of birds and animals. 
• These mites are largely parasitic and consume blood, skin and keratin. 
• Dust mites, which feed mostly on dead skin and hair shed from humans instead of consuming them from the organism directly, evolved from these parasitic ancestors.
• Insects may also be infested by parasitic mites. 
• Examples are Varroa destructor, which attaches to the body of the honeybee, and Acarapis woodi (family Tarsonemidae), which lives in the tracheae of honey bees. 
• There are hundreds of species of mites associated with other bee species, and most are poorly described and understood. 
• Some are thought to be parasites, while others beneficial symbionts. 
• Mites also parasitize some ant species, such as Eciton burchellii.
• Some of the plant pests include the so-called spider mites (family Tetranychidae), thread-footed mites (family Tarsonemidae), and the gall mites (family Eriophyidae). 
• Among the species that attack animals are members of the sarcoptic mange mites (family Sarcoptidae), which burrow under the skin. 
• Demodex mites (family Demodicidae) are parasites that live in or near the hair follicles of mammals, including humans. 
• Acari are mites, except for the three families of ticks.
• The tropical species Archegozetes longisetosus is one of the strongest animals in the world, relative to its mass (100 μg): It lifts up to 1,182 times its own weight, over five times more than would be expected of such a minute animal.
• Mites also hold the record speed; for its length, Paratarsotomus macropalpis is the fastest animal on Earth.

MEDICAL SIGNIFICANCE

• The majority of mite species are harmless to humans, but a few species of mites can colonize humans directly, act as vectors for disease transmission, or cause or contribute to allergenic diseases.
• Mites which colonize human skin are the cause of several types of skin itchy rashes, such as grain itch, grocer's itch, and scabies. 
• Sarcoptes scabiei is a parasitic mite responsible for scabies which is one of the three most common skin disorders in children.
• Demodex mites, which are common cause of mange in dogs and other domesticated animals, have also been implicated in the human skin disease rosacea, although the mechanism by which demodex contributes to the disease is unclear. 
• Chiggers are known primarily for their itchy bite, but they can also spread disease in some limited circumstances, such as scrub typhus. 
• The house-mouse mite is the only known vector of the disease rickettsialpox. 
• Dust mites cause several forms of allergic diseases, including hay fever, asthma and eczema, and are known to aggravate atopic dermatitis.
• House dust mites are usually found in warm and humid locations, including beds. 
• It is thought that inhalation of mites during sleep exposes the human body to some antigens that eventually induce hypersensitivity reaction.

PREVENTION

• Prevention is preferable to having to control an outbreak. 
• This can be summed up as general hygiene and screening of all cultures and material coming into the laboratory and destroying or isolating ail infested material. 
• Even so, separate handling, storage and quarantine of fresh material is desirable, as slightly infested cultures can develop heavy infestation if undetected at first examination. 
• If it is necessary to handle infested material, the culture collection should be well isolated.

 CONTROL

Different workers have varying views on control. 

Some who are handling a quick turnover of infected material may not even regard a few mites as serious, but in a culture collection they spell disaster. 

A combination of prevention and action seems preferable. These can best be classed in several categories: 

1. Hygiene

Hygiene coupled with quarantine is perhaps the best protection.

• All work surfaces must be kept clean.
• Cultures should be protected from airborne contamination.
• Mites can be carried on workers' hands and clothing.
• Cramped laboratory conditions and crowded arrangement of cultures increase the risk of infestation.
• Work surfaces and benches should be washed regularly with acaricide. The acaricide is left for sufficient time to act (overnight) and washed off, preferably with alcohol. As some acaricides are toxic to man, protective gloves should be worn.

The acaricide used at the CMI is Actellic (ICI, Agrochemicals, PLC). 

Other acaricides available for agricultural and grain storage purposes are Murfit, Reldan and Dursban (Murphy Chemicals Ltd) and Satisfar (Sandoz Ltd

As mites appear to become resistant, the acaricide should be changed from time to time.

• Infected cultures should be removed immediately and sterilized if possible. All cultures in the immediate area should be checked and isolated.

2. Fumigation

• Cultures may be stored in cupboards or boxes with acaricides either as preventative or short-term treatment. Camphor and paradichlorbenzene (PDB) have been used for this, but are now regarded as toxic. PDB also has some effect on fungal growth. Drops of Kelthane and Crypo on culture plugs (Smith, 1967) were effective. Current safety practice would suggest that fumigation is no longer desirable.

3. Mechanical and chemical barriers

Many physical methods of prevention of infestation and spread have been tried.

• Cultures are placed on a platform or tray surrounded by water, oil, petroleum jelly or other sticky material. Handling of cultures becomes unpleasant and protection is only from crawling mites.
• Culture bottles or plates may be sealed, but it is necessary to allow growing cultures free respiration, so a means of sealing which is permeable to air is desirable.
• Snyder and Hansen (1946) sealed bottles below screw caps or above the cotton wool plugs (well pushed down) with sterile cigarette papers using copper sulphate glue (20 g gelatin, 2 g copper sulphate, 100 ml water). The pores of the paper allowed respiration but prevented movement of mites, thus protecting clean cultures and isolating infested ones. Care is necessary to ensure the seal is effective. 
• Smith (1971) recommends the use of disposable plastic bottles with plastic caps which, when screwed down, still allow respiration but exclude mites. 
• Smith (1978) described a screw-lid closure with a hole sealed with Metricel.
• Sealing Petri dishes and bottles with various modern plastic tapes often reduces spread but, by means of cracks or wrinkles, mites can eventually penetrate cultures stored for a long time. 
• Tight cotton wool plugs present a considerable barrier but are not completely effective, though a mite that has passed through cotton wool is often much cleaner. Some workers treat plugs with mercuric chloride solution. 
• This kills the mites but is poisonous and dangerous to handle even if a red dye is included to indicate its presence. It is also toxic to fungi.

4. Protected storage

Many methods used for long-term storage of cultures in culture collections prevent infestation.

• Mites do not infest cultures stored under mineral oil. 
• Cold storage at 4-8C greatly reduces movement of mites but does not kill them, so they continue to multiply when the cultures are removed from the refrigerator.
• Deep-freeze storage at approximately -20C usually kills any mites present. Storage in a deep freeze for three or four days can be used prior to cleaning to treat infested material that is too valuable to discard. 
• Freeze-dried ampoules are sealed and totally protected.
• Storage at ultra-low temperatures, for example in liquid nitrogen, gives total protection.
• Cultures stored in silica gel are in vials or bottles with screwed-down caps, so are totally sealed.

REFERENCES : MITES

LICE

INTRODUCTION

• LICE are tiny insects that live on humans and feed on blood.
• When a large number of lice live and multiply on a person, it is called an infestation.

Three different kinds of lice live on humans:

Head lice 

• Are usually found in hair, most often on the back of the neck and behind the ears.
• Head lice are common in preschool and elementary school-age children.
• Adults can get them too, especially adults who live with children.

Pubic lice 

• Also called crabs, are usually found in the pubic area.
• But they may also be found on facial hair, on eyelashes, on eyebrows, in the armpits, on chest hair, and, rarely, on the scalp.

Body lice 

• live and lay eggs (nits) in the seams of clothing. 
• The lice are on the body only when they feed.
• Lice spread easily from one person to another through close contact or through shared clothing or personal items (such as hats or hairbrushes). A louse cannot jump or fly.

The most common symptom of lice is itching.

There are different symptoms, depending on which type of lice you have.

Head lice 

-may not cause any symptoms at first.

-Itching on the scalp may start weeks or even months after lice have started to spread.

-Scratching can make the skin raw.

-The raw skin may ooze clear fluid or crust over, and it may get infected.

Pubic lice cause severe itching.

-Their bites may cause small marks that look like bruises on the torso, thighs, or upper arms.

-If pubic lice get on the eyelashes, the edges of the eyelids may be crusted.

-You may see lice and their eggs at the base of the eyelashes.

Body lice 

-cause very bad itching, especially at night.

-Itchy sores appear in the armpits and on the waist, torso, and other areas where the seams of clothes press against the skin. The lice and eggs may be found in the seams of the person's clothing but are typically not seen on the skin.

Frequent scratching can cause a skin infection. 

In the most severe cases of head lice, hair may fall out, and the skin may get darker in the areas infested with lice.

CLASSIFICATION

• Anoplura: sucking lice, occurring on mammals exclusively
• Rhynchophthirina: parasites of elephants and warthogs
• Ischnocera: mostly avian chewing lice, however, one family parasitizes mammals
• Amblycera: a primitive suborder of chewing lice, widespread on birds, however, also live on South-American and Australian mammals

It has been suggested that the order is contained by the Troctomorpha suborder of Psocoptera.

CAUSES

Lice are very easily spread, usually through close personal contact.

Lice infestation may be caused by any of the three types of lice:

Head lice 

• May be spread through close personal contact, shared personal items (combs, brushes, hats, helmets, clothing, or earphones), or shared bedding.

Pubic lice 

• Are spread mainly through sexual contact and are very contagious.
• Most people become infected after a single exposure to an infected person.
• The lice and eggs may also survive long enough on personal items such as clothing or towels to be spread to another person.
• A child who has pubic lice may have a history of sexual abuse.

Body lice 

• Are most often spread by contact with personal items, especially clothing and hats.
• They are sometimes spread by direct personal contact.
• Lice are spread from human to human.
• Pets don't get head lice and can't spread them to humans.

SYMPTOMS

• Itching, the most common symptom of all types of lice infestation, is caused by an allergic reaction.
• Lice bite the skin to feed on a person's blood.
• The saliva from these bites causes the allergic reaction and itching.
• Itching may not occur right away, depending on a person's sensitivity and history of lice infestation.
• The first time a person is infested with lice, it may take several weeks or months for itching to start or to be noticed.
• In a repeat case of lice, a person may begin to itch within 2 days of infestation because the immune system reacts more quickly when exposure has occurred before.
• Some people become very sensitive to lice bites and have unbearable itching.
• Others build up tolerance to the bites and have little or no itching, even with repeated infestations.
• In addition to itching, symptoms of lice infestation vary depending on which type of lice is present.

Head lice

-Head lice and their eggs (nits) can be seen on hair  the nape of the neck, and behind the ears.

-They can vary in color from white to brown to dark gray.

-The eggs are tiny round or oval shapes that are tightly attached to the hair near the scalp and do not slide up and down on the hair. 

-Frequent scratching may cause broken skin or sores to form on the scalp.

-The damaged skin may weep clear fluid or crust over, and it may become infected.

-In response to infection, the lymph nodes behind the ears and in the neck may become tender and swollen.

Pubic lice

-A pubic lice camera.gif infestation may cause itching around the genitals as well as the anus, armpits, eyelashes, and other body areas with hair.

 -Pubic lice bites may cause small, flat, blue-gray marks (maculae cerulea) that look like bruises on the torso, thighs, or upper arms.

-The marks may last for several months, even after all lice have been killed.

Pubic lice, like head lice, can be seen on shafts of hair.

-Pubic lice that infest the eyelashes and eyelids may cause irritation and crusting in those areas.

-The lice may be visible near the base of eyelashes. 

-Pubic lice tends to be spread by sexual contact.

-If you or your teen has pubic lice, you may also have some other sexually transmitted infection (STI).

-Symptoms of STIs can include itching, tingling, burning, or pain of the genitals. For more information about STIs, see the topic Sexually Transmitted Infections.

TREATMENT

1. Lice will not go away without proper treatment.
2. Treatment should begin as soon as symptoms of lice are noticed or when live lice and eggs (nits) are seen on the person's body or in clothing.
3. Specific treatment depends on the type of lice infestation.

Head lice and pubic lice :

• Killed with over-the-counter or prescription medicines applied to the skin or scalp, and sometimes with a prescription pill.
• The most common way to treat lice is to use medicated creams, lotions, or shampoos that kill lice.
• Some people use a comb to remove head lice and their eggs in addition to or instead of using medicine. 
• In Britain, where lice have become resistant to medicated lotions and shampoos, one study found that using fine-toothed combs with a conditioner (wet-combing) helped get rid of head lice.

Body lice, which live and lay eggs in the seams of clothing, are destroyed by 

• Washing clothing in hot water [130 °F (54.4 °C) or higher] for 5 minutes or more.
• This will usually kill adult lice and prevent eggs from hatching.
• Body lice are only present on the skin when they feed and will usually go away if you bathe daily and wear clean clothes.

Children with head lice can return to school or day care after their first treatment.
Some schools have a "no nits" policy in which the child can go back to school or day care only after eggs have been removed.

 "No nits" policies are discouraged by medical experts. Most doctors agree that a child should be allowed to return to class after proper treatment and should be urged to avoid close head-to-head contact with other students.

Confidentiality should be maintained so as not to embarrass a child who has head lice.

Itching may continue even after all lice are destroyed.

This happens because of a lingering allergic reaction to their bites.

Over-the-counter cortisone (corticosteroid) creams or calamine lotion may help. 

For severe itching, antihistamine medicines (such as Benadryl) or stronger, prescription-strength corticosteroid creams may be needed.

Don't give antihistamines to your child unless you've checked with the doctor first. And don't use cortisone cream for longer than 7 days without talking with your doctor.

Do not use the cream on children younger than age 2 unless your doctor tells you to. 

Don't use it in the rectal or vaginal area in children younger than age 12 unless you've checked with the doctor first.

PREVENTION

• Head lice camera.gif are easily spread among children because kids commonly share hats, combs, and other items.
• If you or your child has head lice, you can help prevent others from getting it if you avoid head-to-head (hair-to-hair) contact during activities inside the home and outside the home.
• Don't share clothing, bedding, hair brushes and accessories, pillows, stuffed animals, or towels.
• Frequently examining the scalps of your school-age children may help you discover and treat lice before they spread to the rest of your family.
• Avoiding prolonged close contact with a person who has lice will also reduce your risk.

• Pubic lice camera.gif are spread primarily among people who have many sex partners.
• Reducing the number of sex partners you have may help reduce your risk of getting pubic lice.

• Body lice camera.gif may be prevented by bathing regularly and changing clothes daily.
• Body lice live on clothing, not on the body. Washing clothing in hot water [130 °F (54.44 °C) or higher] will usually kill adult lice and prevent eggs from hatching.
• Body lice that are on the skin usually go away on their own with daily bathing and wearing clothes that are not contaminated.
• Medicines to kill body lice are usually not needed.
• To help control the spread of lice, you can also clean combs, brushes, clothing, and other personal items to kill lice and their eggs.

OTHER TREATMENT

• Some people try other treatments (such as using petroleum jelly or olive oil to smother lice).
• But there is not strong evidence that other treatments such as these work well or are safe to treat lice.
• Head-shaving helps get rid of head lice.
• But this method can cause distress to the person whose head is shaved. 
• After cutting or shaving the hair, put the hair into a garbage bag right away and seal it so that lice cannot spread to other areas in your home.

REFERENCES : LICE 

FLEAS

INTRODUCTION

• Fleas are the insects forming the order Siphonaptera.
• They are wingless, with mouthparts adapted for piercing skin and sucking blood.
• Fleas are external parasites, living by hematophagy off the blood of mammals and birds.

Scientific classification

Kingdom: Animalia

Phylum: Arthropoda

Class: Insecta

Subclass: Pterygota

Infraclass: Neoptera

Superorder: Endopterygota

Order: Siphonaptera

Latreille, 1825

Suborders

Ceratophyllomorpha

Hystrichopsyllomorpha

Pulicomorpha

Pygiopsyllomorpha

Synonyms

Aphaniptera ნინო

Some flea species include:

1. Cat flea (Ctenocephalides felis)
2. Dog flea (Ctenocephalides canis)
3. Human flea (Pulex irritans)
4. Moorhen flea (Dasypsyllus gallinulae)
5. Northern rat flea (Nosopsyllus fasciatus)
6. Oriental rat flea (Xenopsylla cheopis)

MORPHOLOGY AND BEHAVIOR

• Fleas are wingless insects (1/16 to 1/8-inch (1.5 to 3.3 mm) long) that are agile, usually dark colored (for example, the reddish-brown of the cat flea), with tube-like mouth-parts adapted to feeding on the blood of their hosts.
• Their legs are long, the hind pair well adapted for jumping: a flea can jump vertically up to 7 inches (18 cm) and horizontally up to 13 inches (33 cm), making the flea one of the best jumpers of all known animals (relative to body size), second only to the froghopper.
• If humans had the jumping power of a flea, a 1.8 m (6 ft) person could make a jump 90 m (295 ft) long and 49 m (160 ft) high. 
• Researchers with the University of Cambridge in England found that fleas take off from their tibiae and tarsi (the insect equivalent of feet) and not their trochantera, or knees.
• It has been known that fleas do not use direct muscle power but instead use the muscle to store energy in a protein named resilin before releasing it rapidly (like a human using a bow and arrow), with researchers using high-speed video technology and mathematical models to discover where the spring action actually happens.
• Their bodies are laterally compressed, permitting easy movement through the hairs or feathers on the host's body (or in the case of humans, under clothing).
• The flea body is hard, polished, and covered with many hairs and short spines directed backward, which also assist its movements on the host.
• The tough body is able to withstand great pressure, likely an adaptation to survive attempts to eliminate them by mashing or scratching.
• Even hard squeezing between the fingers is normally insufficient to kill a flea. However, rolling them back and forth a dozen times disables their legs, resulting in death.
• Fleas lay tiny white oval-shaped eggs better viewed through a loupe or magnifying glass.
• The larva is small and pale, has bristles covering its worm-like body, lacks eyes, and has mouth-parts adapted to chewing.
• The larvae feed on various organic matter, especially the feces of mature fleas. The adult flea's diet consists solely of fresh blood.
• In the pupa phase, the larva is enclosed in a silken, debris-covered cocoon.

LIFE STYLE AND HABIT

• Fleas are holometabolous insects, going through the four life cycle stages of egg, larva, pupa, and imago (adult).
• Adult fleas must feed on blood before they can become capable of reproduction.
• Flea populations are evenly distributed, with about 50% eggs, 35% larvae, 10% pupae, and 5% adults.

Eggs

• The flea life cycle begins when the female lays after feeding.
• Eggs are laid in batches of up to 20 or so, usually on the host itself, which means that the eggs can easily roll onto the ground.
• Because of this, areas where the host rests and sleeps become one of the primary habitats of eggs and developing fleas.
• The eggs take around two days to two weeks to hatch

Larvae

• Flea larvae emerge from the eggs to feed on any available organic material such as dead insects, feces, and vegetable matter.
• In laboratory studies, some dietary diversity seems necessary for proper larval development.
• Blood only diets allow only 12% of larvae to mature, whereas blood and yeast or dog chow diets allow almost all larvae to mature
• They are blind and avoid sunlight, keeping to dark places like sand, cracks and crevices, and bedding.

Pupae

• Given an adequate supply of food, larvae will pupate and weave silken cocoons within 1–2 weeks after 3 larval stages.
• After another week or two, the adult fleas are fully developed and ready to emerge.
• They may remain resting during this period until they receive a signal that a host is near - vibrations (including sound), heat, and carbon dioxide are all stimuli indicating the probable presence of a host.
• Fleas are known to overwinter in the larval or pupal stages.

Adult flea

• Once the flea reaches adulthood, its primary goal is to find blood and then to reproduce.
• Its total life span can be as short as one year, but may be several years in ideal conditions.
• Female fleas can lay 5000 or more eggs over their life, allowing for phenomenal growth rates.
• Average 30–90 days
• A flea might live a year and a half under ideal conditions.
• These include the right temperature, food supply, and humidity. Generally, an adult flea only lives for 2 or 3 months.
• Without a host for food a flea's life might be as short as a few days.
• With ample food supply, the adult flea will often live up to 100 days
• Newly emerged adult fleas live only about one week if a blood meal is not obtained.
• However, completely developed adult fleas can live for several months without eating, so long as they do not emerge from their puparia.
• Optimum temperatures for the flea's life cycle are 21 °C to 30 °C (70 °F to 85 °F) and optimum humidity is 70%. 
• Adult female rabbit fleas, Spilopsyllus cuniculi, can detect the changing levels of cortisol and corticosterone hormones in the rabbit's blood that indicate it is getting close to giving birth.
• This triggers sexual maturity in the fleas and they start producing eggs. As soon as the baby rabbits are born, the fleas make their way down to them and once on board they start feeding, mating, and laying eggs.
• After 12 days, the adult fleas make their way back to the mother. They complete this mini-migration every time she gives birth.

CLASSIFICATION

• In the past, it was most commonly supposed that fleas had evolved from the flies (Diptera), based on similarities of the larvae.
• (Some authorities use the name Aphaniptera because it is older, but names above family rank need not follow the ICZN rules of priority, so most taxonomists use the more familiar name).
•  Genetic and morphological evidence indicates that they are descendants of the Scorpionfly family Boreidae, which are also flightless; accordingly it is possible that they will eventually be reclassified as a suborder within the Mecoptera.
• Their evolution continued to produce adaptations for their specialized parasitic niche, such that they now have no wings and their eyes are covered over.
• The large number of flea species may be attributed to the wide variety of host species they feed on, which provides so many specific ecological niches to adapt to. In any case, all these groups seem to represent a clade of closely related insect lineages, for which the names Mecopteroidea and Antliophora have been proposed.
• Flea systematics are not entirely fixed.
• While, compared to many other insect groups, fleas have been studied and classified fairly thoroughly, details still remain to be learned about the evolutionary relationships among the different flea lineages.

Suborder Pulicomorpha
Superfamily Pulicoidea
Family Hectopsyllidae—sticktight and chigoe fleas ("jiggers" of Latin America)
Family Pulicidae—common fleas
Superfamily Malacopsylloidea
Family Malacopsyllidae
Family Rhopalopsyllidae—hosts
Family Vermipsyllidae—hosts: carnivores
Superfamily Coptopsylloidea
Family Coptopsyllidae
Superfamily Ancistropsylloidea
Family Ancistropsyllidae
Suborder Pygiopsyllomorpha
Superfamily Pygiopsylloidea
Family Lycopsyllidae
Family Pygiopsyllidae
Family Stivaliidae
Suborder Hystrichopsyllomorpha
Superfamily Hystrichopsylloidea
Family Hystrichopsyllidae—hosts: rats and mice. Includes Ctenopsyllidae, Amphipsyllidae
Family Chimaeropsyllidae
Superfamily Macropsylloidea
Family Macropsyllidae
Superfamily Stephanocircidoidea
Family Stephanocircidae
Suborder Ceratophyllomorpha
Superfamily Ceratophylloidea
Family Ceratophyllidae

RELATIONSHIP WITH HOST

Fleas feed on a wide variety of warm-blooded vertebrates including dogs, cats, humans, chickens, rabbits, squirrels, rats, ferrets, and mice.

Direct effects of bites

• Fleas are a nuisance to their hosts, causing an itching sensation which in turn may result in the host attempting to remove the pest by biting, pecking, scratching, etc. in the vicinity of the parasite.
• Fleas are not simply a source of annoyance, however.
• Flea bites generally cause the formation of a slightly raised, swollen itching spot with a single puncture point at the center (similar to a mosquito bite)
• The bites often appear in clusters or lines of two bites, and can remain itchy and inflamed for up to several weeks afterwards.
• Fleas can also lead to hair loss as a result of frequent scratching and biting by the animal, and can cause anemia in extreme cases

As a vector

• Besides the problems posed by the creature itself, fleas can also act as a vector for disease.
• Fleas transmit not only a variety of viral, bacterial and rickettsial diseases to humans and other animals, but also protozoans and helminths.
• bacteria: Murine or endemic typhus
• Fleas have helped cause epidemics by transmitting diseases such as the bubonic plague between rodents and humans by carrying Yersinia pestis bacteria
• Fleas can transmit Yersinia pestis, Rickettsia typhi, Rickettsia felis, and Bartonella henselae.
• virus: myxomatosis
• helminth: infestation of Hymenolepiasis tapewormprotozoa: Trypanosome protozoans such as those of the subgenus Herpetosoma, use a variety of flea species opportunistically as vectors
• Fleas that specialize as parasites on specific mammals may use other mammals as hosts; therefore humans are susceptible to the predation of more than one species of flea
• A misconception concerning the carrying/transmission of the HIV/AIDS virus by fleas has been debunked by the Centers for Disease Control and Prevention (CDC 2003).
• According to the CDC and other sources, it is highly unlikely or impossible for fleas to carry the virus or spread it to other humans

FLEA TREATMENT

For humans

1. Fleas can settle in a person's hair in less than ten minutes, causing soreness and itching.
2. The itching associated with flea bites can be treated with anti-itch creams, usually antihistamines or hydrocortisone
3. Calamine lotion has been shown to be effective for itching

For pets

• Flea and tick repellant powder being applied to a dog.
• Modern flea control is approached using Integrated Pest Management (IPM) protocols at the host (pet) level.
• IPM is achieved by targeting fleas during at least two separate life stages, with at least two separate molecules.
•  This is typically achieved using an adulticide to kill adult fleas and an insect development inhibitor (IDI), like lufenuron, or insect growth regulator (IGR), like methoprene, to prevent development of immature stages.
• Flea adults, larvae, or eggs can be controlled with insecticides. Lufenuron is a veterinary preparation (known as Program) that attacks the larval flea's ability to produce chitin, necessary for the adult's hard exoskeleton, but does not kill fleas.
• Flea medicines need to be used with care because many of them also affect mammals.
• Flea treatments that are meant for dogs can be hazardous to cats.[20] Flea and tick ointment is also hazardous to humans; the label of a commercial preparation warns: “First aid: If on skin or clothing, take off contaminated clothing, rinse skin immediately with plenty of water for 15 – 20 minutes; call a poison control center or doctor for treatment advice.
• Although (the product is) applied only between the shoulder blades and at the base of the tail, the dog’s skin and hair oils carry the product over the entire body
• Wash thoroughly with soap and water after handling
• Cedar oil, a non-toxic natural substance, has been proven effective in the eradication of infestations in pets.[
• However, use of some essential oils can be hazardous to cats, especially those containing phenols
• Since more than three-quarters of a flea's life is spent somewhere other than on the host animal, it is not adequate to treat only the host; it is important also to treat the host's environment.
• Thorough vacuuming, washing linens in hot water, and treating all hosts in the immediate environment (the entire household, for example) are essential and if possible must be performed on a regular basis
• Contemporary commercial products for the topical treatment of flea infestations on pets contain pesticides such as imidacloprid, permethrin, and (S)-methoprene.
• All flea control products are recommended to be used at least half-yearly because the life cycle of flea and tick can last to up to 6 months, and by using one of the flea and tick control products for so long, the infestation is highly prevented and, in the end, stopped.
• Although all these products are effective in fighting against flea and tick infestations, they have different active ingredients and, because cats cannot metabolize some of the compounds of the product, care must be taken in their use.

For the home

• Combatting a flea infestation in the home takes patience because for every flea found on an animal, there could be many more developing in the home.
• A spot-on insecticide will kill the fleas on the pet and in turn the pet itself will be a roving flea trap and mop up newly hatched fleas.
• The environment should be treated with a fogger or spray insecticide containing an insect growth regulator, such as pyriproxyfen or methoprene to kill eggs and pupae, which are quite resistant against insecticides.
• Flea fecal material, coiled larva and fleas in the pupae stage combed from a cat, is also called flea dirt.
• Frequent vacuuming is also helpful.
• The vacuum must be used around everything the animal frequents, to pick up all the larvae and eggs.
• Traditional advice recommends disposing of the bag after each vacuuming. One very limited experiment (only one vacuum sweeper used on a single type of carpeted surface) found that vacuuming killed 96 percent of adult fleas and 100 percent of younger fleas.
• This preliminary study's applicability to other circumstances is unclear.
• Diatomaceous earth can also be used as a home flea treatment in lieu of acetylcholinesterase inhibitory treatments or insecticides which carry with them a risk of poisoning for both humans and other animals.
• However, diatomaceous earth dust is harmful to pets and people when inhaled, so use of a dust mask is recommended when applying it
• Application is effective on both the interior and exterior of one's property, but the efficacy of Diatomaceous earth is diminished when introduced to water.
• Diatomaceous earth is commonly available in (amorphous silica) food grade quality; the grade used for pool filters (crystalline silica) should never be used for flea control, as it is not as effective and causes silicosis when inhaled. It is also effective to simply leave it exposed in areas typically vulnerable to fleas and other insects.[29] 
• Bathing can dramatically reduce the flea population on a badly infested animal, especially when in combination with a mild detergent or shampoo, and brushing or combing. 
• Baking soda can be used to kill fleas via dehydration.
• It is available in large amounts as a food grade material and is safe for family and pets when used inside the home on carpets and floors.
• A layer can be sprinkled onto a carpet and worked into the fibers down to where the larvae and eggs are, and will dehydrate and kill them.
• The soda can be easily vacuumed up afterwards on the condition of safe disposal. Often multiple weekly treatments will be required to remove an infestation completely.
• Table salt can also be used inside the home in the same way as, or in combination with, baking soda as a low cost and safe method of breaking their life cycle
• Pulverizing or grinding the salt with a coffee grinder will make it more effective as it will stick to the flea, killing it quicker through dehydration. 
• Dried pennyroyal has been suggested as a natural flea control, but is not recommended in homes with pets due to its high toxicity to mammals. 
• Borax is sold as a "Natural Laundry Booster" and can also be used as another home treatment for flea infestations.
• Borax contains sodium borate which kills fleas by dehydrating them, but its safety for pets is untested. 
• Fleas cannot withstand high temperatures, so a turn through the dryer on medium or high will kill the fleas.
• To collect living fleas from a room or space, eliminate lighting as much as possible while focusing a single source of light just above the floor and directing the light downward. This is best done at night or by covering windows. A sticky bug pad can be placed under the light, or a plate of water mixed with typical soap for the fleas to fall into. The fleas will be drawn to the light and die in the water or be trapped on the sticky pad just below the light.

Vacuuming, temperature and humidity

• A combination of controlled humidity, temperature, and vacuuming should eliminate fleas from an environment.
• Altering even one of these environmental factors may be enough to drastically lower and eliminate an infestation. 
• Vacuuming on a frequent basis, not only the places where the pet lies, but extensively, is particularly effective.
•  A laboratory study done at the University of California showed that vacuuming catches about 96% of adult fleas. 
• In arid areas, less than 5% of flea eggs complete the life-cycle.
• Because humidity is critical to flea survival, eggs need relative humidity of at least 70–75% to hatch, and larvae need at least 50% humidity to survive.
• In humid areas, about 20% of the eggs survive to adulthood. Dehumidifiers with air conditioning and vacuuming all may interrupt the flea life cycle.
• Lower temperatures slow down or completely interrupt the flea life-cycle. Fleas thrive at higher temperatures, but need 21° to 32 °C (70° to 90 °F) to survive.

Drowning

• Fleas can be drowned. One of the best references on the subject is Forensic Entomology: An Introduction By Dorothy Gennard; John Wiley & Sons, Apr 30, 2013; section 4.3 which reflects a 1985 work by Simpson K. (*Journal of the New York Entomological Society 76: 253-265, not finding this online*). Gennard is using the fleas present on a human body at death to determine how long the body had been submerged. 
• A flea submerged for up to 12 hours will appear to be dead, but can revive in about 60 minutes after being removed from the water.
• A flea submerged for 18 – 20 hours will appear to be dead, but can revive in 4 – 5 hours after being removed from the water.
• It takes 24 hours of full submersion to fatally drown a flea.
• Side note; lice can be fatally drowned in about 12 hours.
• Soap can facilitate the death of fleas in bathing.
• The work Medical and Veterinary Entomology by Gary R. Mullen, Lance A. Durden Academic Press, Apr 22, 2009 suggests the process of washing the flea (and the pet) removes integumental waxes on the flea's body and it dies from desiccation (dehydration).
• There does not seem to be a lot of solid research specific to fleas (Siphonaptera) and soap (surfactants), but there are many general insect works.
• There are a number of pesticides which include surfactants (soap) in their make-up to increase effectiveness but these seem to be an aid in the delivery of the pesticide and are not added because the surfactants have any additional killing power. 
• "A surfactant may affect the efficacy of an insecticide by its influence on wetting, spreading and run-off rather than by its influence on cuticular penetration."
• There is some science suggesting soaps can help break down cell membranes but they seem to be most effective on soft bodied insects (which fleas are not) "Soaps kill insects by disrupting the exoskeleton and breaking down cell membranes. Soaps generally work best against small soft bodied insects such as aphids, scale crawlers, meatybugs, and young caterpillars as well as spider mites."

REFERENCES : FLEAS