Week 7 Flashcards
1
Q
Another name for Black Flies
A
Simuliidae
1
Q
Species that commonly bite people
A
Simulium, Prosimulium and Austrosimulium
2
Q
Morphologies of Black flies
A
- quite small, about 1.5–4 mm long
- humped thorax
- usually black in colour, but can have contrasting colours of white or yellowish hairs on legs
- Large compound eyes (Females: separated (dichoptic), Males: touch each other (holoptic)).
- Lens are larger in males
- Mouth are short and broad, do not penetrate through the host’s tissues
- Only female bites
3
Q
Life Cycle
A
- feed on plant juices and naturally occurring sugary substances,
- only females take blood-meals. Biting occurs
outdoors during the day - Eggs can be laid in flowing water
- females land on partially
immersed objects such as rocks, stones and vegetation to lay some 150
– 800 eggs in sticky masses or strings - Eggs are unable to survive desiccation
-Eggs of S. damnosum hatch within 1–2 days, but in many other tropical species the egg stage lasts 2–4 days
- six to eleven (usually seven) larval instars and a
mature larva, depending on the species, is about 4–12 mm long - larvae do not swim
- Attachment is achieved by the posterior hook-circlet (or anal sucker) tightly gripping a small silken pad produced by the larva’s very large salivary glands.
4
Q
Medical Importance
A
- Mansonella ozzardi is a filarial parasite of humans
that is usually regarded as non-pathogenic, but has caused morbidity
in Colombia and Brazil. - Onchocerciasis is a non-fatal disease, often called river blindness, that
is caused by the filarial parasite Onchocerca volvulus. There are no
animal reservoir hosts, so the disease is not a zoonosis
-Black flies are the only vectors of human onchocerciasis.
5
Q
Control Measures
A
- using repellents such as DEET, or by
wearing pyrethroid-impregnated or sprayed clothing - to apply insecticides to
larval habitats.
6
Q
Sand Flies
A
- Family Psychodidae
- 1000 species and subspecies of sandflies
7
Q
Three genera
A
Phlebotomus, Lutzomyia and
Sergentomyia – suck blood from vertebrates, the
former two being the more important because they
contain disease vectors
8
Q
Morphologies
A
- Adult phlebotomines and flies are readily recognized by their minute size (usually less than 5 mm long), hairy
appearance - have e head, thorax, wings and abdomen densely covered with long hairs
- Other blood-sucking flies which are as small as this
are some species of biting midges (Ceratopogonidae), but these have non-hairy wings
-The mouthparts are short and inconspicuous and adapted for blood-sucking
- Only females bite
9
Q
Life Cycle
A
- Some 30–70 eggs are laid singly at each oviposition.
- Larvae are mainly scavengers, feeding on organic matter
- Four larval instars. Larval development is usually completed after 20–30 days, the duration depending on the species, temperature
and availability of food - Adults emerge from the pupae after about 6–13 days
- The life cycle from oviposition to adult emergence, is 30–60 days
10
Q
Adult Behaviours (Life Cycle)
A
- Both sexes feed on plant juices and sugary secretions
- but females in addition suck blood from a variety of vertebrates
- Females of many Phlebotomus species in the Old World and Lutzomyia
species in the New World bite mammals, including humans - Biting is usually restricted to crepuscular and nocturnal periods
- Most species feed outdoors (exophagic) but some
species also feed indoors (endophagic). A few species are autogenous,
that is they can lay eggs without blood-feeding
11
Q
Medical Importance
A
- Annoyance
- serious, but usually localized, biting nuisance. In the Americas up to 100 bites per night have been recorded.
- Bartonellosis
- Sand fly fevers
- Leishmaniasis
- Cutaneous Leishmaniasis (CL)
- Mucocutaneous Leishmaniasis (espundia)
- Diffuse Cutaneous Leishmaniasis
- Visceral Leishmaniasis (kala-azar)
- Post-kala-azar dermal leishmaniasis (PKDL)
12
Q
Control Measures
A
- House-spraying
- Insecticidal fogging
- Personal protection
- New Vaccine
13
Q
Biting Midges
A
Ceratopogonidae
14
Q
Family Ceratopogonidae
A
- almost 5800 species of biting midges in about 125
genera, but only four genera have species feeding on vertebrates
15
Q
Morphologies
A
- Adult Culicoides are very small, being only 1–2.5 mm long
- The head has a prominent pair of eyes, a pair of short five-segmented palps and a pair of relatively long filamentous antennae
- Males do not take blood-meals and have feathery or plumose antennae
- blood-sucking females have non-plumose
antennae - Wings lack scales, the wings are placed over the abdomen
- The abdomen is dull grey, yellowish brown or blackish, and in females is more or less rounded at its tip; in males there is a pair of small, but conspicuous, claspers
16
Q
Life Cycle
A
- laid in batches of about 30–450 on the surface of mud or wet soil
- Eggs usually hatch after 2–7 days, depending on temperature and species
- four larval instars, of which the fully grown larva is cylindrical, whitish, about 3–6 mm long and nematode-like. It has a small, dark (but
unpigmented in Leptoconops) conical-shaped head followed by 12 body
segments - Larval development is sometimes completed within 4–5 days, but may
take weeks in cooler weather - The pupa is 2–4 mm long and the pupal period usually lasts 2–3 days
17
Q
Adult Behaviours (Life Cycle)
A
- Adults of both sexes feed on naturally occurring sugar solutions.
- Females take blood-meals from humans and a variety of mammals and birds.
- Most species bite only outdoors
- About 30 species are autogenous, that is they can mature and lay the first batch of eggs without a blood-meal
- Some species of both Culicoides and Leptoconops are known to fly 2–3 km
without wind assistance. - Adult females are short-lived, most probably surviving for just 1–3 weeks
18
Q
Medical Importance
A
- Annoyance
- veterinary importance
- transmitting arboviruses
- troublesome pests and transmit minor filarial infections as well as Oropouche virus to humans
19
Q
Control Measures
A
- Spraying larval breeding sites with organophosphates such as malathion, diazinon or temephos
- Use of insecticide-impregnated bed-nets (nets are impregnated with
pyrethroids such as permethrin and deltamethrin) - Insecticidal fogs or ultra-low-volume (ULV) applications
- DEET
20
Q
Control Measures
A
- Spraying larval breeding sites with organophosphates such as malathion, diazinon or temephos
- Use of insecticide-impregnated bed-nets (nets are impregnated with
pyrethroids such as permethrin and deltamethrin) - Insecticidal fogs or ultra-low-volume (ULV) applications
- DEET
21
Q
Tsetse Fly
A
Glossinidae
22
Q
Tsetse Fly
A
- belong to the genus Glossina, the only
genus in the family Glossinidae - 31 species and subspecies
- restricted to sub-Saharan Africa
- Tsetse flies are vectors of both human and animal
African trypanosomiasis, the disease in humans being
called sleeping sickness.
23
Q
Important vectors
A
G. palpalis, G. tachinoides, G. fuscipes, G. pallidipes
and G. morsitans
24
Q
Morphologies
A
- Adults are yellowish or brown-black robust flies
that are rather larger (6–14 mm) than houseflies - a rigid forward projecting proboscis
- a closed cell between wing veins 4 and 5 which, with
a little imagination, looks like an upside-down hatchet
(i.e., axe, cleaver or chopper) and consequently is often
termed the hatchet cell
25
Q
Life Cycle
A
- The saliva containing anticoagulants is pumped down into the wound formed by the fly
- Both sexes take blood – meals
- Both male and female tsetse flies bite people
- blood-feed about every 2–3days
- Feeding is only in daytime
- Larval development takes about 9 days, by which time
the third- and final instar larva is 5–7 mm long - bears a pair of prominent dark protuberances called the polypneustic lobes, which
are respiratory structures - fly’s abdomen is enlarged
-Females select shaded sites for larviposition.
- Duration of the puparial period is comparatively
long, usually 4–5 weeks
26
Q
Adult behaviours (Life Cycle)
A
- spend about 23 hours a day resting on vegetation
27
Q
Three main groups of tsetse flies:
A
- Fuscagroup (forest flies)
- Morsitans group(savannaflies)
-Palpalis group (riverine and forest flies)
28
Q
Medical Importance
A
- Sleeping sickness
29
Q
Control Measures
A
- Insecticide control
- Targets and traps
- Genetic Control
- Future Control
