Umm Al-Qura University بسم الله الرحمن الرحيم Umm Al-Qura University Health Sciences College at Al-Leith Department of Public Health Lecture (8)

Sand flies

Objectives 1/ Define of Sand fly species. 2/ Define Sand fly classification, Geographical Distribution, External morphology, Life cycle, Adult behavior and Medical important. 3/ Understand the role of Sand fly in Transmission of parasitic diseases. 4/ Understand the Mechanisms of Sand fly disease Transmission to human. 5/ Define Treatment of Sand fly diseases and Prevention. 6/ Apply of Sand fly control methods.

Sand flies Classification Phylum : Arthropoda. Class : Insecta. Sub Class : Ptrygota. Order : Diptera. Sub Order : Nematocera Family : Psychodidae. Sub family : Phlebotominae.

There are about 600 species of sand flies There are about 600 species of sand flies. The genera phlebotomus and lutzomyia are most important in the transmission of diseases to man.

Distribution: Widely distributed in the tropics and subtropics. phlebotomus species occurs only in the old world. Lutzomyia species found only in the new world.

External morphology: Adult phlebotomine sand flies can be recognized by their: Minute size (2-5 mm in length) hairy appearance, Sand flies have the head thorax, wings and abdomen densely covered with long hairs

The antennae are long and segments with short hairs are similar in both sexes Wings are lancelet in out line. in sandflies the wings are erect over the body when the fly is at rest.

The wings venation in phlebotomine sandflies vein two branches twice.

the abdomen in the female rounded at the tip but in males it terminates in a prominent pair of claspers. male female

The minute eggs 0.3-0.4 mm are ovoid shape, usually brown or black Life-cycle: The minute eggs 0.3-0.4 mm are ovoid shape, usually brown or black about 15-100 eggs are laid singly at each oviposition, oviposition sites are small cracks,holes In the ground and Stable floor. Egg are not laid in water

eggs hatch after about 6-17 days under optimum condition Larvae are mainly scavengers, feeding on organic matter, such as fungi animal faeces and decomposing bodies of arthropods There are four larval instars, the mature larva is 4-6 mm long

Sand flies larvae identify by the present matchstick hair on the head and all body segments Larval development is completed after 21-60 days the duration depending on species

The larval skin, whoever is not completely lost off but remains attached to the end of the pupa Adult emerge from the pupae after about 7-14 days

Sandfly Pupa

Adult behavior: both sexes feed on plant juices and sugar secretions but females in addition suck blood from variety of vertebrates. biting is usually restricted to nocturnal periods and during the day in darkened room. adults are weak fliers and do not usually disperse more than a few hundred meters from their breeding places.

Medical importance: 1- Annoyance Biting nuisance (a condition known in the near east as harara). 2- Leishmaniasis Leishmaniasis occurs in two main forms. Dermal (cutaneous) and (visceral) leishmaniasis, old world leishmaniasis (oriental sore,) is caused by leishmania tropica.

American dermal leishmaniasis caused by several leishmania species such as the Le. Braziliensis and Le mexicana complexes. The visceral form of leishmania in the old world (kala-azar) is caused by leishmania donovani and Le.infantum.

Leishmania aethiopica

Cutaneous Leishmaniasis:

Leishmania tropica

Leishmania braziliensis braziliensis

Visceral Leishmaniasis:

Prevention and control Prevention and control of leishmaniasis requires a combination of intervention strategies because transmission occurs in a complex biological system involving the human host, parasite, sandfly vector and in some causes an animal reservoir host. Key strategies for prevention are listed below: 1-Early diagnosis and effective case management. 2- Vector control. 3- Effective disease surveillance. 4- Control of animal reservoir hosts. 5- Social mobilization and strengthening partnerships.

Thanks Radia 30