Flies Flashcards
Order?
Diptera (2 wings)
Presence of wing ?
Adult - yes, one pair
Some - wingless
Feed on?
vertebrate blood or on saliva, tears or mucus
IH OF ?
helminth and blood protozoan
Alternately feed
on feces and on food
Vectors of
bacteria, viruses, spirochetes, chlamydia
larvae (maggots)
Live on subcutaneous tissues of the skin, respiratory passages, or GI tract of vertebrate host -myisasis
Larvae vs adult
different structure and behaviour
lifecycle
complex with complete metamorphosis
some are parasites only in larval stages
MORPHOLOGY
DIVISION
SIZE
DIFFERENTIATED THROUGH
HEAD, THORAX AND ABDOMEN
SIZE 0.5 MM - 10 MM
is differentiated through wing patter, mouth parts, colour or pattern on thorax and abdomen
Life history
Holometabulous life cycle
EGG > LARVAE > PUPAE > ADULTS
Larvae undergo complete metamorphosis - entire body is reorganised and reconstructed
Pupa is a bridge between juvenile and adult. It is metabolically very active - old larval tissue and organs are lost - replaced by adult organ
EGG STAGE
Most flies are oviparous where oval eggs laid in batches
A few species are oviviparous where the egg hatch in oviduct and female deposits larvae
Larvae (maggots) stage
3-5 larval stages
Soft, legless and segmented
In some species, are parasitic (myiasis)\
Pupae stage
Visible external appendages
Develops within a cocoon or puparium
Adult stage
Duration of life cycle and length of time adults live vvary between species
Direct pathogenic significance
Dermatitis or pruritus (esp in blood-sucking fly)
Hypersensitibity reaction (painful bites) - culicoides in horses
Secondary infection (bite wound provides sites for screw worns (CHRYSOMYIA BEZZIANA)
Downgrading of hides (hypoderma and myiasis)
Blood loss (mosq, tabanids - 0.5 litre blodd per day from one cow)
Indirect pathogenic significance
Disturbance (annoyance and irritation)
- stamping behaviour and self-injury
- irritation due to bites and salivation
- peak activity , eg culicoides, mosq - intolerable to human and man
IH to trypanosome, anaplasma and dirofilaria immitis
Disease - trypanosomiasis, anaplasmosis, filariasis
Production loss - milk and meat up to 20% (S. calcitrans)
Examples of nematocera (small mosquito)
Culicoides
Aedes
Anopheles
Culex
Example of brachycera ( large fly)
Tabanus
Chrysops
Haematopota
Both sexes feeding on blood
stable flies, horn flies, buffalo flies, tsese flies, sheep keds and louse flies
Female feeding on blood
black flies, sand flies, biting midges, mosquitoes, horse flies, and deer flies
Examples of cyclorrhapha
small to medium mosquito
Musca
Stomoxys
Haematobia
Chrysomya
General morphology of nematocera
small, slender and delicate
Long filamentous antennae, composed of many articulating segment
Long and narrrow wing with conspicuous longitudinal veins
Pendulous palp with 4 to 5 segment
Female is parasitic and have piercing mouthparts
Egg laid in or near water - aquatic larvae and pupae - larvae are mobile and have recognizable head
Culicoides (Biting Midges-agas)
Over 1000 species
Feed on birds and mammals
Painful bites causing pruritic dermatitis (hypersensitivity reaction) in horses
Feed mainly on head and neck hosts
Breed in damp, marshy ground or decaying vegetation
Larvae aquatic lives on edges of lakes, streams, mud holes, etc
Only female are blood feeders
Not strong fliers - stay close to host and breeding sites
Importance of midges
Bites causing itching and swelling
Causes allergic dermatitis in horses
IH of filarial worms in man and in animals (onchorcerca in cattle and horses)
Ih of Leucocytozoon cauleryii in poultry
Transmit BT in sheep
Transmit fowl pox
Culicidae (mosquitoes)
Aquatics breeders
Feed on nectar and plant juices but females need initial blood meal for ovarian development and between each egg batch
Importances of culicidae
Cause considerable nuisance and reduced productivity, exhibit severe hypersensitivity reaction - secondary bacterial infection.
More important to man (malaria, dengue fever and various form of encephalitis
Life cycle of culicidae
4 larval stages
Aquatic- distinct head with 1 pair of antennae
Hatch depends on temperature
Pupae are at water surface, mobile and coma-shaped
Adult short lifespan - female(2-3w) , male shorter - string fliers
Feeding periods of mosquitos
Culex: nocturnal , active at night
Aedes: diurnal, active at day times
Anopheles: crepuscular, active at twilight
Pathogenic effects of mosquitoes
Annoyance and blood loss
Decreased milk and meat production
Intermediate host for several parasites
a) filarial parasites - Dirofilaria immitis - culex, anopheles (heartworms)
b) malaria parasites - Plasmodium juxtanucleare and P. gallinaceum
c) mechanical carriers - fowl pox (culex, aedes)
Brachycera morphologies
Large flies up to 25 mm long large broad head and bulging eyes with stout antenna
3 segments of antennae with annulation at the last segment
Cross vein present at vein
Female use slashing sponging mouthparts to pierce skin of host and then feed on pooled of blood (combination of sponging and blood sucking)
Eggs on vegetation overhanging mud and shallow water - large larvae - aquatic and mobile - usually found in mud
Maxillae function
cut skin and pull blood
Labium and labellum function
suck blood
Importances brachycera
Bites are deep and painful causing disturbance
Mechanical vectors of anthrac, pasteurella, retrovirus, pesti virus, trypanosoma and anaplasma
Pathogenic effects of Tabanids
Animal restless - painful bites and irritating
Mechanical carriers of:
bacterial diseases - anthrax, tularaemia
viral diseases - equine infectious tularaemia
Protozoan disease - surra (trypanosoma evansi), sleeping sickness (t. brucei), anaplasma marginale
Cylorrhapha
Small to medium sized flies
Short, 3 segment antennae with last segment have feather like attachment - arista
Wings-cross venation
Small maxillary palp
Sponging mouth parts of cyclorrhapa
Feeding on liquid film
Eg: house flies, blow flies and face flies
Biting mouthparts of cyclorrhapa
puncture skin and drink blood
eg: stable flies, horn flies, tsetse flies
Larvae
mobile and worm like > maggots
Pupate on ground and immobile
Musca ; house fly
m. domestica, m. sorbens
Liquid feeders, no piercing mouth parts
Nuisance pests of livestock and human
Morphology of musca
grey thorax with 4 dark longitudinal stripes
abdomen yellow brown
Life cycle of musca
Eggs laid in batches about 100-500 every 3-4 days interval
In feces, decomposing organic material - larvae hatch within 12 hours
3 Stadia - matured larvae 8-12 mm long (3-4 days)
Pupa in dry cool sites near breeding material bury in ground - reddish brown puparium.
LC can be completed in 7-10 days
Pathology
Closely associated with livestock, humans, buildings and organic wastes
Potential transmission of viral, bacterial and parasitic organism (hair, body and regurgitation).
Pathogen include thypoid, cholera, tuberculosis, anthrax and conjuctivitis
Hematobia
smaller than stomoxys calcitrans, about 4 mm long
Palp as long as proboscis
Thorax with 2 dark stripes
Hovers around face and body of cattle and buffaloes
Infestation reahes 1000-4000 flies per animal and to as high as 10,000 to 20000 per animal
haematobia (lyperosia)
info
Buffalo fly - h. exigua, buffalo and cattle as host
smallest blood sucking muscid- greyish like musca but biting fly
Both sexes feed several time per day - feed frequently (40x)
Close to host, in swarms and fly away only to lay eggs on fresh faeces
Effects on hosts
Interferes with grazing period
Bites are painful and irritating causing intense irritation and skin wounds may attract myiasis flies
Fly specking
Blood loss, low milk and meat production by 10-20%
Transmit surra, anthtax and HS
IH of habronema and stephanofilaria stilesi
Stomoxys calcitrans (stable flies)
Resembles musca domestica - similar in size + grey + 4 longitudinal stripes on thorax
7-8 mm long
Biting mouthpartss
Abdomen shorter and broader than musca domestica
Both male and female feed on blood
Life cycle
Habitat: in and around farm building
Feed: blood, several times a day
Rest: walls,fences or trees
Eggs: laid in wet straw, old stable bedding or manure
laid in batches of 20 to 50, total up to 700 pupation in complete darkness, complete lc in 4 weeks
Pathology effects of stomoxys calcitrans
Painful bites, annoying and destructive pest of horses and ruminants
May cause 10-15% loss of body weight reductio in milk in some cases up to 40-60%
Mechanical transmitter of protozoa (T. evansi, T. brucei, etc (all t.)), bacteria (bacillum anthracis, P. multicoda (HS). Equine infectious anemia
IH of Habronema spp. Stomach worm of horses
Epidemiological Triad
Host
Availability of host
Maggot at wound, untreated navel
Epidemiological Triad
Environment
Depend on species
Availability of breeding material and cleanliness
Available all year round
Epidemiological Triad
Agent
Depend on species, breeding sitem feeding material
WAYS TO CONTROL FLIES
- personal protection - repellant, proper clothing
- Application of insecticides on animals and habitat - dipping, sprays, mist or fogs
- Habitat modification
- altered water flow level
- larvae/pupae of nematocera in oil film
- constant removal of faeces - Sanitation and surveilance
- fecal management, food storage, environment and water disposal - Baits and traps
- light traps, sticky traps, tunnel traps, electrocution - Biological (predators, natural competitors, parasites/pathogen)
- dung beetle, wasp, aquatic predator - Genetic control
- gamma radiated pupae, sterilise male - Chemicals
Benzol - kills maggots
Pyrethroids - residual sprays
Pyrethrins - short half life
Fenoxycarb - insect growth regulator
What is myisasis flies
Dipterous insects whose larvae invade tissue and organs of man and animals causing myiasis
Adults dont suck blood
Grouped according to their ovipositioning and larvapositioning habits
Accidental myisasis
Rare chance event of myiasis
Accidental ingestion of fly eggs
Eg: musca spp, sarcophaga spp
Obligatory myiasis
A living host is required to complete development (will not survive without a living host)
Eg: scwrew worm flies, bot flies, warble flies
Facultative myiasis
Living host tissue is not required to complete development
eg: flesh flies, green bottle flies, blue bottle flies, black bottle flies
Life history
Egg deposited on animal or vegetation > hatch in 24 hours > 3 larval stages follow (with feeding) > After 3rd stage larva finishes feeding drops off host and finds as suitable place to pupate (usually burrows into the ground) > after pupation, adults emerge (may or may not feed before mating and depositing eggs)
Screw-worm myiasis
Chyrysomya bezziana
Only species causing cutaneous myiasis in animals, occasionally in man
characteristics of chrysomya bezziana
Bluish-green fly with orange-brown eyes
Female will only lay eggs on injured skin or body orifices of any warm-blooded animal
Are veracious tissue feeders - large foul smelling wounds
OBLIGATE PARASITE IN WOUND - feed on living tissue and never developns or carcass or other organic materials
Predisposing factors of lalat hijau
wound resulting from dehoning, castration and branding
tick and fly bites
perineal area of a cow that has recently calved
Navel of newborn calves
Pathology
C/S
irritation, discomfort, pruritus, weight loss, reduced fertility
Heavy infestation causes severe tissue damage, hemorrhage, anaphylaxis, toxemia, and or bacterial infections (cause death if not treated)
Treatment and control
Occlusion or suffocation - force larvae to surface to search for air - remove them by forceps or tweezers
Lidocaine - swelling force larvae to surfaces - easy to be grasped and removed
Ivermectin treatment
Drench and dip sheep with insecticides toprevent larval growth
Wound cleaning - apply myiaseptic cream +nagasunt power and bandage
daily wound cleaning and larvae removal
Repeated process until wound is free of maggots
