What is Entomology Entomology is the branch of

What is Entomology ? Entomology is the branch of zoology which deal with the study of insects.

What is Medical Entomology ? Medical Entomology concerned with those arthropods which transmit diseases from one host to another host. For example anopheles mosquitoes, sand flies, ticks and mites.

What is Vector ? n Vectors are those living agents which transmit or help to transmit disease from infected person to a healthy person i. e. anopheles mosquito transmit malaria and house fly transmit pathogens/ bacteria from one place to another place.

VECTOR CNT……. n There about twelve species of anoph mosquitoes in Rawalpindi & Islamabad area. n Anoph. stephensi is urban specy. n Anoph. culicifacae is rural specy. n Vectors are of two types. Mechanical and biological.

What is Metamorphosis? n This is a process of development in insects from an egg stage to adult form. So the collective change occur from an egg stage to adult form is called Metamorphosis.

Types of Metamorphosis n There are two types of Metamorphosis. Complete Metamorphosis. n In this type of metamorphosis there are four developmental stages and the newly emerge larva are completely different from the adult one. For example mosquito and sand fly. n n Egg------ Larva------ Pupa------ Adult

Incomplete Metamorphosis In this type of Metamorphosis there are three developmental stages and the newly emerged Nymph is just like the adult one in there morphology and habit but smaller in size, for example lice and bedbug. n Egg------ Nymph------ Adult n

What are various arthropods of medical importance? Mosquito House fly Flea

Sand fly Tsetse fly

Cont. Lice Bed Bug Tick

Cont. Mite Cyclops

Transmission of Arthropods-born diseases 1. By direct contact: - The arthropods are transferred by direct contact for i. e. scabies and pediculosis.

Cont……. 1. By mechanical transmission: The disease agents are transfer mechanically by arthropods i. e. diarrhea, typhoid & paratyphoid.

Cont……. . 1. By biological transmission: - When the disease agents are multiply in the body of vector i. e. malaria.

Habits of mosquitoes A knowledge of the habit is essential from the point of view of controlling of arthropods as will as for a proper understanding of the point they play in disease transmission. n Distribution: Throughout the world (Tropical & temperate n region) Bites: Only female mosquitoes can bite in the evening or in the early part of the night. (Haematophagous) n Breeding: Anopheles prefer clean water for breeding while culex breed in dirty water. Aedes breed in artificial collection of water.

Cont…… n Feeding: Anthrophilic (those insects which prefer to suck the blood from human beings)/Zoophilic (those insects which prefer to suck the blood from animals) n Resting: Endophilic (those insects which rest inside the house)/Exophilic (those insects which rest outside the house in bushes) Dispersal: The normal range of flight is about 2 -3 kms from their breeding places. n Life span: It depends upon the environmental conditions, average life period of female mosquitoes are 2 -3 weeks and male are short lived. n

Medical importance n Genus Anoph: Malaria n Genus Culex : Filarial& viral encephalitis n Aedes : Yellow fever & dengue fever

Difference between Anopheles/Aedes. Mosquitoes Anopheles Aedes Egg 1) Laid singly about 100 -250 eggs. 1) 2) Eggs are boat shaped and 2) provided with lateral float. Laid in clusters or rafts, each raft containing 100 -250 eggs. Eggs are oval shaped, and not provided with lateral float. Larvae 1) Rest parallel to water 1) surface 2) No siphon tube are present. 2) 3) Palmate hairs are present. Suspended with head downward and make an angle to water surface. Siphon tube are present. Palmate hairs are absent. 3)

Pupae 1) Siphon tube is broad and short 1) Siphon tube is long and narrow. Adults 1) When at rest inclined it an angle to surface. 2) Wings spotted. 3) Palpi long in both sexes. 1)When at rest, the body exhibit a hunch back. 2) Wings unspotted. 3) Palpi short in female.

Culex

n Aedes

Life cycle of mosquito Metamorphosis complete. n Egg: Anopheles female lay eggs singly in fresh water, size about 1 mm, boat shape, lateral float are present. Laid About 100 -250 eggs. Eggs are not visible by naked eye. n Culex female lay eggs in stagnant & polluted water in raft, oval in shape and lateral float are absent. n

Cont…… n. Larva: after 2 -3 days larva emerge from egg, actively swimming on water surface and feed on algae, fungi & bacteria. Larva is about 1 -6 mm long. Body is divided into three parts (head, thorax & abdomen). Spiracles (respiratory organs) are present on abdomen. Palmate hairs are present on abdomen which help larvae to float in water.

Cont. n Pupa: after 5 -7 days larva becomes pupa. Pupa is Comma shaped and moved actively on water surface. The body is divided in cephalothorax and abdomen. Two small respiratory trumpets are present on thorax. It does not feed. The pupal stage lasts for 1 -2 days.

Cont…… n Adults: when the adult emerge from pupa, it rest for a while on the pupal skin then flies away. Under favorable environmental conditions the life cycle is completed in 7 -10 days. Normally the adult mosquito lives for about 2 -3 weeks.

Cont…. .

Cont…. .

Control Measures n Biological control: Use of parasites, n Genetic control: Release of sterile male predator (fish & frog) and pathogens. The best known fish are Gambusia affinis and lobister reteculatus. mosquitoes in the field. Which will compete with the natural fertile male mosquito in mating & the population will be automatically reduced.

Cont…. Environmental control: To eliminate their breeding places. This is also known is source reduction. Filling, leveling and drainage of breeding places. Chemical control: Anti larval chemicals like Paris green, mineral oil. Anti adult chemicals like Melathian, Fenthian and abate.

Protection against mosquito bite Screening of doors, windows and ventilation’s of house/hospital. Mosquito net should be tucked around the bed. Insets repellants like Deet , dimethyle, phthlate and dimethyle carbate are available in local market in shape of oil, cream & lotion. It should be used on the exposed parts of the body.

Classification of sandfly n Phylum: n Class: n Order: n Family: Arthropoda. Insecta. Diptera Psycodidae.

Cont…… Genus: Species: Phlebotomus. (a) P. papatasii (b) P. Sergenti © P. argentipes

Habit of Sandfly n Distribution: Found in the warm countries. n Bites: Only female sandfly can bite in the dwelling at night and take shelter during day in holes and crevices in wall, in dark room and store room etc. n Breeding: The eggs are laid in damp and dark places in cattle shed and poultry.

Feeding: Mostly species are nocturnal in habit. Dispersal: The range of flight is 200 yard from their breeding places. Life Span: Average life of sandfly is about 2 weeks.

General Characters of Sandfly The body of sandfly consists of three parts: Head: The head bear a pair of long and hairy antenna. Palpi and proboscis and one pair of prominent black eyes. Thorax: The thorax bears a pair of wings and three pair of legs. The wing are upright in shape and hairy. The 2 nd longitudinal vein branched twice. The legs are long and slender and out of proportion to the size of the body.

Cont…… Abdomen: The abdomen has ten segment and is covered with hairs. In the female the tip of abdomen is rounded while in male claspers are attached to last abdominal segment.

Medical Importance: Cause sandfly fever, kala-azar, oriental sore and leishmaniasis.

Life cycle of sandfly The life cycle of sandfly is characterized by complete metamorphosis, having 4 developmental stages. n Egg: The female generally lay eggs in the damp dark places in the cattle sheds & poultry. The eggs vary from 40 -60 in number, brownish in colour. The eggs measure about 0. 4 mm in length. Eggs hatch from 1 -2 week. n Larva: The larva is maggot like structure, having large head, thorax and abdomen and two long bristle on last abdominal segment. Larva feed on decaying organic matter and become a pupa in about 2 weeks.

Cont…. . Pupa: Pupa found in cracks and cervices in the wall. The pupa stage last for about 1 week. Adult: The average life of a sandfly is about 2 weeks.

Control measures n Sandfly are easily controlled because they do not move long distance from their breeding places. Insecticide: Lindane has been proved effective. Spraying should be done in the human dwelling, cattle sheds and poultry. Its residue may remain effective for a period of 3 months.

Cont…. . n. Sanitation: Removal of shrubs and vegetation, filling of cracks and crevices in the wall & floor and distance of cattle sheds and poultry from human habitations.

How you will differentiate between mosquito and sandfly?

Cont…… Mosquito n n n Size is 4 -5 mm long Black in colour Lay about 100 -250 eggs Flight range is about 2 -3 km Life period is about 2 -3 weeks Sandfly n. Size is 2. 5 mm long nyellowish brown in colour n. Lay about 40 -60 eggs n. Flight range is about 200 yards n. Life period is about 2 weeks

Classification of house fly n n n Phylum Class Order Family Specy : : : arthropoda Insecta Diptera Muscidae Musca domistica

Medical Importance House fly is a potential vector of many diseases. like Typhoid, paratyphoid fever, diarrhea, dysenteries, cholera, gastroenteritis and amoebiasis.

Habits of Housefly The habits of housefly make it suitable for the spread of disease Distribution: The housefly occurs all over the world. Breeding: Housefly breeds in fresh horse manure, human excreta, garbage, decaying fruit and vegetables.

Feeding: Housefly does not bite. It is attracted to food by its sense of smell. It can not eat solid food. It vomits on solid food to make a solution of it and then suck it in a liquid state. Defecation: The housefly has the habit of defecation constantly all the day. Thus it deposits countless bacteria on exposed food. Dispersal: Housefly can disperse 3 -4 miles from their breeding places.

General Characteristics of Housefly The housefly is a medium size common insect, from light to dark gray in colour. The body is divided into three parts. Head: The head bear a pair of compound eyes, a pair of antenna and a retractile proboscis, which is adapted for sucking liquid food. Male eyes are closer together, while female eyes are set apart widely.

Cont…… Thorax: Thorax has 2 -4 well developed dark longitudinal stripes. Thorax bears a pair of wings and three pair of legs. The legs and the body are covered with short and stiff hairs, called tenent hairs which secretes a sticky substance. Abdomen: The abdomen is 4 segmented shows light and dark marking. In female a tube like structure is extended from the abdomen when the fly lay her eggs.

Life cycle of Housefly The housefly undergoes a complete metamorphosis. Egg: The female lay about 120 -150 eggs in one siting. Eggs are laid in horse manure and other decaying materials. Creamy white in colour and about 1 -2 mm in length. The fly lays from 600 -900 eggs during her life time. The eggs hatch in 8 -24 hours. Larva: The larva is 12 segmented, white in color and about 1 -2 mm in length at birth. At the anterior and posterior end of the body a pair of spiracles are present. The larva feed on decaying organic matters. The larval period lasts from 2 -7 days.

Cont…. . Pupa: The pupa is dark brown in colour. The pupa stage last from 3 -6 days but in winter it may be prolonged. Adult: The complete life cycle from egg to adult may take 5 -6 days during summer. Flies do not live longer than 15 days in summer and 25 days in winter.

Transmission of diseases 1. Mechanical transmission: Flies are potential vectors and efficient mechanical spreaders of many diseases and most of that can be spread by mechanical transmission. Housefly transport microorganism on their feet and hairy body. Pathogenic organisms, ova and cyst have been recovered from the bodies of the common housefly. Pathogens remains alive for 36 hours on their feet.

Cont…. . 1. Vomit drops: The vomit drop is a rich bacterial culture. By its habit of repeatedly vomiting, the housefly infect foods and there by transmit disease. Infection remains alive for 8 days in vomit. 2. Defecation: The excrement of housefly has been found to contains microorganism, cyst and ova of intestinal parasites. By its habits of constant defecation, the houseflies spread these diseases. Infection remain alive for 18 days in the faeces.

Control measures 1. Protection against flies: Screening of houses, hospitals, food market, restaurant and other similar establishment will give considerable relief from houseflies. The doorways and windows should be screened. Screen should be made of non-crassive material, such as copper or aluminum gauze.

Cont…. . 2. Environmental control: The best way to control the housefly is to eliminate their breeding places and improvement in environmental sanitation on a community basis. All domestic refuses should be placed in strong plastic bags and the opening should be tightly closed. Regular refuse collection twice a week to prevent any egg laying among the refuses developing to adult. The refuses should be burned or buried properly. A clean house with clean surrounding is the best answer to the fly problem.

Cont. 3. Insecticidal control: Commercially available aerosol dispensers are commonly used in home as a spray to kill flies. They contains knock down insecticides such as 0. 5% dichlovos or 0. 2% pyrethrins. Spraying of residual insecticides such as 3% malathion or 1% dimethoate are remain effective for 1 -2 months. Special care should be taken to prevent contamination of food or water during spraying operation. Poisoned baits containing 1 or 2 % diazinon and malathion have been tried with success. Liquid baits containing 0. 1 to 0. 2% of the same insecticides and 10% sugar water have given good results.

Cont…. 4. Health education: It is difficult to control the flies without the co-operation of the people. Fly control campaigns require organized individuals and community efforts which is the basis of successful public health programmed. It is only through health education that people can be motivated with a desire to get rid of flies permanently.

Classification of Flea n Phylum : Arthropoda n Class : Insecta n Order : Siphonaptera n Family : Pulicidae n Species : 1. Human Flea (Pulex irritans) n 2. Rate Flea (Xenop cheopis) n 3. Cat & dog Flea (Ctenocephalus can

n Medical importance: Fleas are known to transmit the following diseases. Plague, endemic typhus and chiggerosis.

Habits of Flea n Distribution: Flea are found through out the world on their normal host in the nest, burrow and hair of their host. n Bites : Both the sexes bite and suck the blood from their host.

Cont…. . Feeding: Both the sexes are ectoparasites and feed usually once a day. Dispersal : Flea can not fly but they jumps about 4 inches when starved. Mainly flea are disperse by their host. Life period : Adult flea may live up to one year.

General characters of flea Flea are small wingless insect and the body is covered with strong bristles backwardly. The body of flea is divided in to head, thorax and abdomen. Head : The head is conical in shape and bears short piercing & sucking type of mouth parts, which project downwards from the head.

Cont…. . Thorax : The thorax is composed of pro-thorax, meso-thorax and meta-thorax and from each thorax one pairs of strong legs attached. The hind legs are modified for jumping. Flea has no wings. Abdomen: The abdomen consist of 10 segments. In male a penis is present on last abdominal segment and in the female a spermatheca is present in the posterior part of the abdomen.

Life cycle of Flea There are four stages in the life cycle of flea and metamorphosis is complete. Eggs : The eggs are small (0. 5 mm) and white in colour. They deposited among the hairs of the animal host. The female lay about 300 - 400 eggs in her life time at the rate of 2 - 6 at a time. The eggs normally hatch in 2 - 7 days. Larvae : The larvae are small, legless, white in colour and bear long hair on their bodies. The larvae has no eyes but very sensitive to light. Larvae feed on organic matters and the blood in the faeces in the adult flea. There are three larval stages and the last stag form a cocoon. The duration of the larval stage is about 2 weeks.

Cont……. Pupa : The pupa develops inside the cocoon. The pupal stage last for 1 - 2 weeks dependingupon environmental condition. Adult : The life cycle of a flea may be year. completed within 3 weeks. The infected flea may live for 1

Mode of transmission 1. Biting : The chief method of transmission in case of plague is the bite of hungry blocked flea. Some flea which ingest plague bacilli become blocked due to the multiplication of plague bacilli in their stomach. Flea affected in this way are called blocked flea, so due to this blockage flea are unable to obtained further blood feed. Because of hunger, flea begin to bite more forcefully to suck the blood, so instead of sucking blood it injects plague bacilli to the wound. Such blocked flea play a great role in the spread of plague.

Cont…… 2. Mechanical transmission : It takes place from the proboscis of the flea, which had fed recently on infected rodent. 3. faeces : The faecal drop of infected flea may contained numerous bacilli. When the host scratch the flea bitten area, there is a direct inoculation of the infected agents in to the injury spot.

1. General flea index : It is the average number of all species of flea per rodent. 2. Specific flea index : It is the average number of each species found per rodent.

Cont…. . 3. Percentage incidence of flea species: It is the percentage of fleas of each species found per rodent. 4. Rodent infestation rate : It is the percentage of rodents infested with the various flea species.

Control measures 1. Insecticidal control : The cheapest control measure is the use of DDT dust but the rate flea have developed resistant to DDT. In such areas carbryl or dizanon (2%) or malathian (5%) are prove effective. The spray should be applied to floors and walls up to a height of about 1 feet. Animal host like cat and dogs premises should also be sprayed with these insecticides.

2. Repellents: Deet and benzyl benzoate are effective flea repellents. It should be applied to the exposed parts of the body. Clothing impregnated with diethyltouamide repels flea for more than a week. 3. Rodent control : Flea control should be followed by rodent control.

Classification of louse n n n Phylum : Arthropoda Class : Insecta Order : Anoplura Family : Pediculidae Species: 1. Body louse (pediculus humanus 2. Head louse (pediculus capitis)

Habits of louse Distribution: Louse occur in all parts of the world specially in colder climate are more affected. Bites: Both the sexes suck the blood from mammals and birds. They bite severely and are annoying pest. Feeding: Louse is permanently active parasite found in hairs. Cloths and on the body of the host. Dispersal: Louse is wingless insect and disperse by close contact, overcrowding. Louse may also be acquired from clothing , bedding and using comb of infested person. Life period : Under favourable environmental condiction adult louse live from 30 -50 days. Medical importance: louse are vectors of epidemic typhus, relapsing fever, pediculosis, trench fever and dermatitis.

General characters of louse Louse is a small , wingless insect of mammals and birds. The head and body lice differ very little in structure except in their habitat. Head : The head bears a 5 segmented antenna. The mouth parts are adapted for sucking blood. Thorax: Three pairs of legs are attached ventrally to the thorax. The legs are strongly developed and are provided with claws which help the insect to cling to their hairs and clothing. Abdomen: The abdomen consist of 9 segments. The last abdominal segment is pointed in case of male and bilobed in case of female.

Life cycle of louse There are three stages in the life cycle of louse. Metamorphosis is incomplete. Eggs: The eggs are laid singly or in groups. They are firmly attached to the hairs or seams of clothing by cemented substance. Eggs are small, pointed at one end and white in colour. The female lays up to 300 eggs at the rate of 4 -9 a day. Under favorable environmental conditions of temperature the eggs will hatch in 6 -9 days. The eggs will not hatch if the temperature is below 22 c. Nymph: The nymph look like the adult except for its smaller size. It feeds on host and developed in to adult after passing through 3 moults. The nymph stage may take 10 -15 days. Adult : The entire life cycle from egg to adult takes about 15 -17 days under favorable conditions. Adult louse live from 30 -60 days. If unfed louse kept away from their host it will die with in 2 -5 days. Blood fed louse may survive up to 10 days. Heavily infested person have 400 -500 louse on their head and cloth.

n DISSEMINATION OF LICE 1. DIRECT CONTACT: Lice are disseminated by 2. INDIRECT CONTACT: Lice may also be close contact with lousy or infested persons. Overcrowding provides an excellent opportunity for the direct transference of lice from one person to another. Children get easily infested at school when their heads come together at work or play. acquired from clothing. bedding, combs or brushes used by lousy persons. Lice have been seen to be blown to leave the host whose temperature rises above or falls below the normal.

Control measures

Classification of Bed Bugs Phylum C lass Order Family Species Arthropoda Insecta Hemiptera Cimicidae a) Cimex Lectularus (Urban specy) b) Cimex Hemipterus (Rural specy)

Habits of Bed Bug Distribution: World wide distribution. Found in tropical and temperate regions. Bite: Commonly take blood-meal during night but in starving they also feed during the day in dark rooms. Feeding: Both male and female commonly feed on man, rabbits, mites and bats. Dispersal: They usually spread to new houses by being introduced with furniture, bedding and buying second hand furniture. Life Span: Average life of bed bug is from several weeks to many months. Under laboratory condition adult have lived up to 4 years. Medical importance: Bed bugs are not known to transmit any disease to man but they are a public health problem because of their persistence biting at night which may lead to sleeplessness. The repeated feeding on infants has been reported to cause iron deficiency.

General characters of bed bug The adult bed bugs are wingless insects, about 4 -5 mm long. When unfed its colour are yellowish or brown but after full fed they become dark brown. Head: The head is short and broad and has a pair of compound eyes, a pair of four segmented antenna and three segmented proboscis which are appressed along the ventral surface of the head and thorax. Thorax: Prothorax is much larger than the meso-and met-athorax. Three pairs of legs arise from the thorax, which are selender and well developed. Abdomen: The abdomen is divided into eight visible segments. In adult male the tip of abdomen is slightly more pointed than the female. Seven spiracles are located ventrally on 2 -8 abdominal segments.

Life cycle of bed bug Both male and female suck the blood and are equally important as a pest. Incomplete metamorphosis occur in bed bug. Egg-nymph-adult. Eggs: Female lay about 2 -3 eggs a day in the same places where the bugs hide. The eggs are yellowish white in colour about 1 mm long. Some 300 eggs can be found in cracks and crevices of building and furnitures. The eggs usually hatch after 8 -11 days. Nymph: The newly hatched bug is pale yellow in colour and resemble as adult but is much smaller in size. There are 5 nymphal instars. This period c commonly last for 5 -8 weeks. Adult: Adult bed bug can live 6 -9 months without food. Bed bug can withstand a long period of starvation up to 500 days. Under laboratory conditions adult may live up to 4 years.

Control measures 1. 2. Floors and walls of infested houses together with as much furnitures as possible should be sprayed with 1 -2% malathion or 0. 5% diazanon. Bedding and mattresses can be lightly sprayed with insecticides but should be aired after wards to allow them to dry out completely before being reused.

Classification of Tick Phylum: Class: Order: Family: Specy: - Arthropoda Arachnida Metastigmata (Hard tick) Ixodidae (Soft tick) Argasidae Hyalomma, Boophilus annulatus Medical Importance: Hard ticks transmit Tick typhus, Viral fever, viral hemorrhagic fever, CCHF and tick paralysis.

General Characters of Ticks The body of ticks is oval in shape and consist of cephalothorax and abdomen. The capitulum (false head) project forward beyond the body out line and is visible from above. They have four pairs of legs and are terminate in a pair of claws. Ticks has no antenna. The palps are swollen and three segmented. Hard ticks have a dorsal scutum. In the male covered the entire body while in female it is much smaller. In adult female the genital opening is present near the second pairs of legs and one pair of eye are present.

Habit of Ticks Distribution: Hard ticks have a world-wide distribution. Feeding Habits: Both male and female suck blood from their host and feed during night and day. Dispersal: Ticks are wingless, they may be dispersed up to several kilometers on their host or by crawling. Life Period: Hard ticks may live up to several years.

Life cycle of Tick Metamorphosis is incomplete: Egg-Larva. Nymph-Adult. Egg: Female lay about 1000 -8000 eggs all at one time and after that the female dies. The egg are brown in colour and deposited on the ground. After 2 -3 weeks the eggs hatch larva. Larva: The tick larva possess 3 pairs of legs. The larva lies in wait of a suitable host and when host appears attaches himself with them. After taking a blood meal it drops off and become a nymph. The larval period may vary from 3 -13 days. Nymph: The nymph resembles the adult ticks having 4 pairs of legs. The nymph also attach themselves to a suitable host for blood meal. The nymph feed for 4 -8 days on the host then drop off and moult to the adult stage. Adult: The adult repeat the process of host finding, the engorged female drops off the host and hide away in a suitable location to digest the blood meal and lay her egg hatch. The duration of life cycle from egg to adult stage is about 2 months.

Difference Between Hard & Soft Ticks Hard ticks Soft ticks Scutum Covers the entire back in males. Only a small portion in front in females. Absent Head Situated at anterior end. Lies ventrally not seen from above. Spiracles Situated behind 4 th Coxa. Situated between 3 rd & 4 th Coxa. Eggs Several 100 or 1000 laid in one sitting. Laid in batches of 20100 over a long period. Nymph One Five Habits Cannot stand starvation, feed night and day. Stand starvation years or more. Diseases Ticks typhus, viral encephalitis, hemorrhagic fever, tick paralysis and tularemia. Relapsing fever. for

Control Measures Environmental Control: Cracks and crevices in ground particularly near building should be filled up. Animals host like such as wild rodent and dog should be reduced. Insecticidal control: Recommended treatments include solution of 0. 5% malathian. 0. 1% dichorvos or alternatively dust of 5% carbaryl and 3 -5% malathian can be applied to the coats of pets. Repellent: Suitable repellent such as dimethyle pathalate and benzyle benzoat can be used on the skin or alternatively clothing cab be impregnated with these to prevent ticks infestation.

Classification of Mites Phylum Class Order Family Specy : : : Arthropoda Arachnida Astigmata Sarcopidae Saecopets scabiei Medical Importance: Scabies mites are not vectors of any disease but cause the condition known in man as scabies, acariasis and itching.

General Characters of Mite The scabies mites is visible with nacked eyes, about 0. 4 mm in size and white in colour. The body shape is rounded like a tortoise. Dorsally the mite is covered with bristles. Adult have four pairs of short legs divided into five segments. The front legs end in long tubular processes, known as suckers and the hind legs end in long bristles. The male has suckers on all the legs except the 3 rd pair.

Life Cycle of Scabies Mite Metamorphosis is incomplete. Eggs: The female scabies mites select place on the body where the skin is thin such is between the fingers and wrists etc. The female burrowed in to the superficial layer of the skin and make tunnels in which she lays about 30 eggs at the rate of 2 -3 per day. Larva: After 3 -4 days the eggs hatch in to larva. The larva are six legged. These larvae crawl out from the burrows. Come to the surface and bore in to the hair follicles where vesicle form. After about 3 days the larvae mature in to nymph. Nymph: The nymph develop in to adults in 6 -8 days. Adult: The life cycle from egg-egg take about 14 -31 days. The female mites may live about 1 -2 months on man. Away from man they may survive for about 7 -10 days under ideal condition.

Mode of Spread Close contact: Scabies is usually transmitted by close contact with an infected person like sleeping in the same bed or children playing with each other. Contaminated clothes: The disease may also be transmitted by contaminated clothes.

DIAGNOSIS OF SCABIES 1. 2. 3. 4. The patients complains of itching which is worse at night. Examination reveals follicular lesions at the affected sites. The diagnosis is probable if the other member of the house are also affected. Confirmation of the diagnosis may be made by searching the parasites in the skin debris under microscope.

CONTROLE OF SCABIES 1. BENZYL BANZOAT: 25% banzyle benzoat is effectives against sarcopidae. It should be applied with a brush from the neck downward and after allowing some 5 -10 minutes to dry. The application should be repeated after 12 hours. 1. MITIGAL: It is yellowish sulfurs ointment which is painted undiluted over the body from the neck downward. A single treatment is 100% effective. In epidemic condition it is important to treat all members of a family living in close association.