1. The document describes the tsetse fly (Glossina species), which transmits human African trypanosomiasis (sleeping sickness) and animal trypanosomiasis (Nagana).
2. It provides details on the classification, morphology, life cycle, behavior, habitat, and medical importance of different Glossina species.
3. Specifically, it notes that Glossina palpalis transmits Gambiense sleeping sickness mainly in West and Central Africa, while G. morsitans transmits Rhodesiense sleeping sickness in East Africa.
2. Learning objectives
By the end of this lecture students should be
able to:
1- Classify Tsetse flies.
2- Describe the morphology of the fly.
3- Know their life cycle, bionomics and habitat.
4- Know the medical importance of Glossina.
3. Classification of glossina (Tsetse fly)
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Diptera
Family: Glossinidae
Genus: Glossina
Species: G. Morsitans, G. Fusca and G. Palpalis
groups (23 subspecies).
4. Introduction
In Sudan tsetse has the local name ‘Umm Bogeni’
and officially in the atlas of the Republic of the
Sudan ‘El zubabah’.
Morsitans group (Savanna) found a cross West
Africa to Central and East Africa.
Palpalis group ( Riverine ) only found in West
Africa.
Fusca group ( Forest) found in central , West and
East Africa.
5.
6. Descriptions of glossina spp
(Tsetsefly)
General look and the descriptions of the head:
Tsetse flies are narrow-bodied yellowish to dark brown
insects.
At rest the wings are held over the back in a scissor-like
manner.
They are about 6-13.5 mm long depending on the
species.
The antenna of glossina, has three segments, the third one
is largest bent dorsally and tapering.
Antenna has arista whish has branching hairs on the
dorsal side only.
The proboscis is from piercing and sucking type, it is
long, held horizontally and has long palps.
7.
8. Descriptions of glossina spp
(Tsetsefly)
Descriptions of the wings:
The venation of the wing is very characteristic,
especially the course of the M1+2 vein which looks
like the hatchet (meat cleaver or axe shape).
10. Life cycle of glossina species
Glossina give birth to mature larvae (Larviparous).
The egg matures in the ovary after which it is passed in
the uterus to become fertilized by a sperm from the male
to become embryo.
The embryo takes four days to develop into the first
instars larva.
The larva feed on milk derived from the female milk
(accessory) gland and undergoes three moults to
become the fourth instars larva.
Female deposit the larva in the ground under shade in
soft soil.
11. Life cycle of glossina species
Larva buries itself immediately and turns into a
pupa.
Pupa need 4-5 weeks to give adult.
Depending on food and breeding habitat it can
produce larva every 10 days.
12. Behavior and habitat of
glossina
Resting:
dark and humid sites.
Shaded places in forested areas, the lower woody parts of
vegetation.
Holes in the trunks of trees.
Most species rest at height below 4 meter.
Feeding:
Feed on blood of human, animals, reptiles and birds.
Diurnal insects.
Attraction to the host:
Carbon di-oxide.
Large and dark object.
13. Medical Importance of glossina
species
Vector of human (sleeping sickness) and animal
(Nagana) trypanosomiasis.
Gambiense sleeping sickness (caused by
Trypanosoma brucei gambiense) is a chronic
disease and is found mostly in West and Central
Africa.
Rhodesiense sleeping sickness (caused by
Trypanosoma brucei rhodesiense) is an acute
disease that occurs mainly in East Africa.
14. Medical Importance of glossina
species
Gambiense sleeping sickness is mainly transmitted by
tsetse flies belonging to the G. palpalis group.
These flies attack people at places along rivers,
lakeside villages and along roads bordered by
vegetation.
Rhodesiense sleeping sickness is transmitted by
savanna species belonging to the G. morsitans group.
These species normally feed on wild animals that
inhabit savannas and woodlands, like domestic
animals, such as cattle and goats.
