Lice Life Cycle

Introduction

Lice are wingless insects that are nourished by the blood of animals. They mainly infect the scalp and skin of mammals as well as birds. Which gives rise to tremendous itching and leads to rash around the hair lines. Head lice are most common and primarily found in children. Lice can multiply very quickly and spread from one person to another. The main reason for the lice infestation is the lack of proper hygiene.

Characteristics of lice

The general characteristics of lice are listed below.

• It is a tiny wingless insect that is nourished by the blood of mammals as well as birds.

• The antenna is segmented into five parts and it is held up by the head.

• The mouth part of the lice is specially adapted so that it can suck blood.

• The legs of the lice are ventrally connected to the thorax.

• Three pairs of legs are present in lice.

• The legs are well developed and strong with claws. That helps the lice to grasp onto hair and clothing.

• The abdomen is segmented into nine parts.

• If it is a male louse the last segment of the abdomen is pointed while in females it is bilobed.

• It is an active parasite found in the hair, scalp, and body parts (on clothing) of the affected person.

• It has a life period of about 30-50 days.

• It spreads by close contact with the affected individuals.

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Types of Louse

There are three types of louse and they are listed below −

• Head lice (Pediculus humanus capitis) − It affects the scalp. Especially common in kids.

• Public lice (Pthirus pubis) − It is also known as crab louse. It affects genital areas.

• Body lice (Pediculus humanus corporis) − It affects other parts of the body and is often found in cloth fibers. The body lice are different from the lice found in the head and genital areas. They are bigger in size, lay eggs and leave behind wastes in the affected area or clothing.

Physical Features of a Lice

• The colour of lice may vary from white, yellow, brown, or black.

• It has a flattened body that ranges in length from 0.33 mm to 11 mm.

• It has narrow anterior mouthparts.

• All the species of birds have chewing lice.

• While mammals have either sucking lice or chewing lice.

• The density of the louse population varies depending on different individuals and climatic conditions.

Life Cycle of Lice

There are three stages in the life cycle of a lice. Incomplete metamorphosis is observed in lice.

• Eggs − Eggs of lice are also known as nits. It is a very minute structure and the size is about half the size of the head of a pin. It is oval in structure and its colour may vary from white, yellow or black. It is found close to the scalp and is challenging to remove. The hatching period of the lice eggs is almost 8 to 9 days.

• Nymph − A nymph is a new-born louse that hatches off from the eggs. Its growth stage is between 9-12 days and is nourished by the blood of humans. Nymphs can move fast and generally, they avoid light.

• Adult lice − Its size normally ranges from 2mm to 3 mm. They are brown, white, yellow or black. The Colour may be light or dark. The adult lice have three pairs of legs and claws that hold the hair tightly. The life span of adult lice is approximately 30 days when stuck to the head. But they will die within a day or two when it falls down.

Causes of Lice Infestation

Lice are found in the human head, body and genital areas. A sticky substance is generated by the female louse which attaches the egg surface to the scalp.

The main causes of louse infestation are listed below −

• Head to head or body-to-body contact − This can happen when children, family members and friends interact and play closely.

• Closed shared spaces − The clothes that have lice when kept in the closets, lockers in hostels or schools increase the chance of spreading. They can also spread through shared combs, pillows, blankets and stuffed toys.

• The items that have been shared among friends and family members − These include clothing, headphones, hair brushes, hair accessories, towels, blankets, etc.

• Contact with furniture that has lice on it − Sometimes lies can be present on beds, sofas, etc., and when used by someone they can spread.

Symptoms of Lice Infestation

• Skin irritation because of itching on body parts, genital parts and scalp.

• Scrape marks near scalp, shoulder and neck. Too much itching leads to a red bump in the affected area and sometimes it is infected with bacteria.

• Around the waist, genital areas, and upper thigh bite marks can be observed.

• The existence of lice can be observed in the scalp, body clothing, body hair and genital areas.

• The tickling feeling from the movement of hairs.

Diagnosis and Treatment of Lice Infestation

Generally, health care professionals use magnifying lenses to identify lice. They also use light known as wood’s light to check the presence of lice eggs. The light helps to diagnose the eggs by making them look pale blue in colour.

The treatments for lice infestation are as follows −

• Non-prescription products − The shampoo that contains permethrin is the first option to kill lice. Sklice is a lotion toxic against lice.

• Oral prescription drug − Stromectol is an oral medicine prescribed by health professionals when other methods are not effective against lice.

• Topical prescription drugs − Malathion is a drug that is effective against lice and highly flammable.

Apart from these home remedies and proper hygiene keeps lice away from us.

Prevention of Lice Infestation

• Avoid head-to-head contact.

• Do not share personal belongings with others like hats, combs, hair accessories, coats, etc.

• Try to avoid shared spaces with others.

• Maintain personal hygiene.

Conclusion

Lice are wingless insects that are nourished by the blood of animals. Head lice are the most common and primarily found in children. Lice can multiply very quickly and spread from one person to another. The main reason for the lice infestation is the lack of proper hygiene. Lice are found in the human head, body and genital areas. Generally, healthcare professionals use magnifying lenses to identify lice. They also use light known as wood’s light to check the presence of lice eggs.

FAQs

Q1. What do you know about the antenna?

Ans. The antenna is a set of sense organs in insects that are present near their head.

Q2. What is the abdomen in insects?

Ans. Both reproductive and digestive organs are present in the abdomens of insects.

Q3. What is permethrin?

Ans. It is a synthetic substance that is obtained from the chrysanthemum flower. It is toxic to lice.

Q4. How can Sklice is used?

Ans. It is used in dry hair for 10 minutes after that it should be rinsed with water.

Q5. Why malathion is flammable?

Ans. Malathion contains a high percentage of alcohol and it is highly flammable.