Myiasis Myiasis

Invasion of organs and tissues of vertebrates with dipterous larvae  Myiasis is a serious problem for the livestock industry, causing severe economic losses worldwide.

 Although infestation by fly larvae is much more prevalent in animals

 It is a relatively frequent occurrence in humans in rural, tropical and subtropical regions Different Items

 Cutaneous  dermal or sub dermal  Urogenital  Ophthalmic  Nasopharyngeal  Intestinal myiasis  Aural Myiasis  Nosocomial Myiasis

Not a specific type of myiasis but rather refers to myiasis in a hospital setting

Unfortunately it is quite frequent, as patients with open wounds or sores can be infested if flies are present I. creeping myiasis II. furuncular myiasis III. trumatic myiasis

A. obligatory B. facultative In spite of animals there is no obligatory intestinal and urogenital myiasis in human Accidental swelling Considerable discomfort, abdomen pain, diarrhea, vomiting Living larvae passed through,,,, Musca or Fannia spp Accidental Urogenital myiasis Much pain in Urogenital tract  When larvae occur in wounds, removal is simple under aseptic condition

When they are more deeply imbedded surgery may be needed Classification:

Three families : I- Calliphoridae II- Sarcophagidae III- Oestridae Calliphoridae I- Non-metallic calliphoridae

1-1- Cordylobia anthropophaga - in Africa (possibly western Saudi Arabia)

Life cycle:  eggs were laid on dry soil and sand, especially contaminated with urine or excreta  Underclothes or babies nappies  Larvae attach themselves to the suitable host directly or indirectly  It berried completely except……

Mature larvae wriggle out Buries and make puparium

Medical importance:

Boil like swelling on any parts of the body Use medical liquid paraffin to extract larvae

2- Metallic Calliphoridae

2-1- New world screw worms ( Cochliomyia hominivorax) 2-2- Old world screw worm (Chryzomya bezziana( 2-3- Greenbottles ( Lucilia spp) 2-4- Blubottles ( Calliphora spp) 2-1- New world screw worms ,Cochliomyia hominivorax

•Used to occur in south America

•Eradication by genetic control from Mexico and central America

•A population was discovered in Libya in 1988 and eradicated in 1991

 Metallic green to bluish green  red or orange head

Life cycle

Eggs were laid on the edges of the wounds, sores, dried blood cloths, healthy mucous membranes, umbilicus newborn babies

Active larvae burrow deeply, feed gregariously

Three larval instars

Tend to penetrate deeply into tissues, so

2-2- old world screw worms ( Chrysomya bezziana)

 Tropical Africa, Indian subcontinent, south-east Asia to China, it has been introduced to several countries on the west coast of the Persian Gulf

Similar to new world screw worm , with different distribution Medical importance:

Both are obligatory parasite

Considerable damage and disfigurement, esp. if face attacked

When larvae invade natural orifices cause pain and misery May result impair speech Should be treated immediately Surgery may necessary

2-3- The Green bottles( Lucilia spp)

 Lucilia sericata World wide distribution Metallic or coppery green Life cycle:

Female normally their eggs on meat, fish, decaying carcasses, or near wounds

Maggot-shape larvae

Adult frequently visit carrion, sores, wounds……..

Common around unhygienic places, slaughterhouses and piggeries

Commonly fly into houses, noisy buzzing flight

3-3- The Bluebottles ( Calliphora spp)

 World wide distribution Metallic-bluish Life cycle similar to Lucilia

Medical importance of  the dirty habit of these flies makes them potential vectors calliphora of some pathogens spp and lucilia spp:

Medical importance is associated with facultative myiasis

Both larvae have been found in many parts of the world developing in wounds and ulcerations, esp. with pus

 They are recorded also in hospital underneath the bandage  No important damage in such cases  Occasional intestinal myiasis, no serious harm

No obligatory intestinal myiasis

II- Sarcophagidae

 II-1: Sarcophaga spp.

II-2: Wolhlfahrtia spp.

Cause myiasis, possibly mechanical vectors

They are unusual in that females are larviparous, that they deposit first-instar larvae instead of eggs

Worldwide distribution II-1: Sarcophaga spp

 non-metallic, grayish Three longitudinal strips on thorax  Abdomen with chequer-board appearance Life cycle:

 Adult do not lay eggs  Larvae laid on decaying carcasses, animal excreta, sometimes in wounds

Medical importance:

 Mechanical vectors of various pathogens

Larvae occasionally deposited in wounds, little damage Feed on necrotic tissues

Accidental intestinal myiasis, discomfort and pain before passing the larvae out with the feces

II-2: Wolhfahrtia

Three longitudinal stripes, but not chess-board pattern, roundish lateral spots and triangular- shaped dark marking Life cycle of Wohlfahrtia spp.

 deposit larvae The most important species , W. magnifica, obligatory parasite of humans and animals in western Europe, middle east, north Africa and central Asia to China  larvae are deposited in scratches, sores, never in decaying material In people ears, eyes and nose are frequently infested, make deafness, blindness, death Like screw worm, larvae can burrow deep into tissues III- Osteridae III-1- Dermatobia hominis

Life cycle of Dermatobia hominis:

 Interesting and remarkable life history  Females glue their eggs to the body of other arthropods  Embryos within attached eggs mature into first instar  Hatch when the carrier settle on warm-blooded animals

larvae penetrate the skin and burrow to the subcutaneous tissue. Each larvae produces a boil-like swelling with an opening Medical importance:

Larvae invade subcutaneous tissues of humans in various parts Boil like swelling which suppurate , may attract other myiasis  a lot of discomfort and pain Because of many spines on larvae difficult to remove, so surgical removal with a local anesthetic

III-2- Oesterus ovis

 Sheep warble  It deposit larvae instead of eggs

In Iran the following myiasis were recorded:

I. Oesterus ovis II. Chrysomya bezziana III. Wohlfahrtia magnifica IV. Hypoderma spp V. Dermatobia hominis Maggot therapy

THE MOST INTERESTING EXAMPLE OF USING INSECTS IN MEDICINE INVOLVES THE LARVAE OF THE BLOW FLY.

STERILE MAGGOTS OF THE GREEN BOTTLE FLY

Lucilia sericata  Written records have documented that maggots have been used since antiquity as a wound treatment.

 There are reports of the successful use of maggots for wound healing by Maya Indians and tribes in Australia.

 There also have been reports of the use of maggot treatment in Renaissance times. ( 1350-1600)

 During warfare, many military physicians observed that soldiers whose wounds had become colonized with maggots experienced significantly less morbidity and mortality than soldiers whose wounds had not become colonized.

 These physicians included Napoleon’s surgeon general, who reported during France's Egyptian campaign in Syria, 1829, that certain species of fly destroyed only dead tissue and had a positive effect on wound healing.

Modern use

 While at Johns Hopkins University in 1929, Dr. Baer introduced maggots into 21 patients with intractable chronic osteomyelitis

 He observed rapid debridement, reductions in the number of pathogenic organisms

 All 21 patients' open lesions were completely healed and they were released from the hospital after 2 months of maggot therapy.

 A 56-year old man with diabetes, was referred to hospital by his general practitioner for evaluation of a 4 cm diameter non-healing ulcer on his right leg  MDT was initiated in the hospital's Diabetes Unit, and the patient was sent home.  By the time the patient returned the following day, the wound had been debrided significantly.  A second 24-hour cycle of maggots was applied, and the patient returned home. His wound was completely clean the following day and it healed completely within eight weeks of treatment

Forensic entomology

Forensic medical entomology  Calliphoridae  In Loss of insects  PMI  toxicology