Public Health Vectors and Pests

Fly

 
Common Name Dog dung fly
Scientific Name Musca sorbens
Size These flies are small, they have a length with ranges from 6-8 mm
Colour Musca sorbens are greyish-brown in colour
Description Musca sorbens is selective it does not enter homes and darkened areas. And it is not attracted to fresh food; it is attracted to garbage instead. It prefers to feed on cow dung and dog faeces. It looks like a half-sized house fly, but it characterised by its shiny two-stripped thorax. It keenly feeds on human eyes and on nasal discharge and intentionally moves from eye to eye.
Musca sorbens is more attracted to wounds, sores, skin lesions searching for food like, blood and other exudations. Even though they don’t bit, they are capable of transmitting eye and diarrhoeal diseases to humans and livestock due to pathogens.
 
Habitat Musca sorberns reside in solid faeces lying on the ground.
 
Lifecycle A total of 42 eggs are laid and they hatch in 10 days.
The first growth stage: larvae burrow through the dung and remain there until they mature. The three larval growth stages complete development in 4-5 days, it feeds on the dung. Mature larvae leave the dung during the night and pupate during the day. In about 5 days adults begin to emerge during the late afternoon or early afternoon. In adult stage: a high number of females emerge during the first night
 
Disease Transmitted Musca sorbens transmits Chlamydia trachomatis which causes trachoma. Trachoma.
 
Symptoms Stage 1: early symptoms:
- Eye redness, watering eyes, swollen eyelids, sensitivity to bright light.

Stage 2: about 7 to 10 days later:
- Eyelid small red lumps.

Stage 3: Progression of eyelid lumps for a period of 3 to 4weeks:
- Multiple eyelid lumps,enlarging eyelid lumps.

Stage 4: Spread to cornea and eye:
- Eye pain, corneal scaring, progressively dimming vision.
Type of Damage A chronic follicular conjunctivitis that leads to scarring in the conjunctiva and cornea. It causes corneal ulceration and corneal opacities resulting in decreased vision and blindness.
 
Sources / Breeding Pastoral homesteads provide sufficient breeding sites
The females lay their eggs on cracks and clefts of the dung in cluster of over a hundred. Females are capable of multiple egg laying; they complete two ovarian within two weeks. A female deposits an average of 42 eggs each cycle. The number of eggs laid by a female depends on the following factors: female size, longevity, and nutrition. Eggs hatch in about 10 days.
 
Prevention Proper stool disposal in latrines can reduce the chances of Musca sorbens to invade homes. Musca sorbens can be easily controlled without the use of insecticides, unless they have unless they have flooded a farm. This control can be achieved in the long-term if sanitation and prevention are the bases of the control programme.

Trash areas which are outdoors must be kept clean. Garbage should be drained and wrapped in plastic bags before they are put in the bins outdoors. Dust bins can be fitted with plastic bags inside and be closed with tight fitting lids. This also reduces odour coming from rubbish. Containers should be washed regularly. Bins should be located far from the house or building.

Remove potential breeding material like, mulch, leaves, manure, garbage and animal excreta.
Household and livestock-related garbage, dumped at the local landfill, can quickly generate large numbers of flies, especially when the garbage already contains fly eggs, larvae, or pupae. Landfill workers must be aware of this possibility and compact and cover such garbage at least twice weekly.
Occasionally, wet farm garbage e.g., wet, spoiled grain; wet, waste from calf pens that is brought to the landfill is loaded with fly maggots and pupae. Landfill workers should be alert to this and immediately compact and cover such material. Thousands of adult flies may emerge from such garbage within a few hours.
Moist pet foods left outdoors for several days should be avoided. Fermenting or over-ripe fruit should be removed from the ground. Any potential breeding material should be spread thinly in the field and allowed to dry to prevent fly development.
Dispose of animal carcasses (including livestock, pigs, and poultry). Collected carcasses must be removed quickly during the summer. Otherwise, they will quickly be the source of flies within 24-48 hours.

Prevention through exclusion

Flies seem to be able to find their way into homes, garages, shops, and bins through the smallest of overlooked entrances. Even when all windows have good screens, when all doors have screened storm doors, and when all known cracks and crevices have been filled with caulking, the odd fly seems to get inside the home. Just everyday coming and going through the back door allows agile flies to get inside the home.
Sometimes, they are able to find their way into attics and, from there, into the home proper through various vents and electrical outlets. Thus the rout of entry to buildings should be blocked by all means .Screen doors should open outward and have fitted springs for tight closing. Doors should be kept closed at all times to prevent entry of flies into the buildings or homes.

Manure Management

Solid animal waste which is collected from enclosures for confining livestock should be dried off quickly and be used as compost for agricultural purposes soon after drying. Clean cattle pens, drainage areas, loafing sheds, stalls, feeding aprons, spilled feed, pet droppings, and other decaying organic matter at 10-day intervals to minimize fly breeding.
Liquid wastes can be pumped from holding pits, in the spring or fall, to be spread over or injected into fields.
The right time to spread manure is in the spring, as soon as the fields are dry enough to travel on with spreading equipment. In the fall, after harvest is complete, is the second best time.
 
Control Control with the use of fly swatters and tapes

Swatters can be used in doors to eliminate the flies that have invaded the building. Tapes should be used in verandas and garages to trap the flies.

Vacuuming control

Flies found inside in the fall may also be removed with a vacuum. Because flies are drawn to light, attract them to a bright window in an otherwise darkened room, making it easier to vacuum them. This method is especially useful in cluster fly control.

Control with electric light traps

Electric light traps are also effective; they can be used in homes. Some are designed to be unobtrusive, mixing in with the décor. They are more ineffective outdoors.

Chemical Control

Pyrethrums and other chemicals can be used.

Environmental control consists of cleaning garbage collection areas and the residues found at bottoms of trash cans, keeping loading docks clean and using other physical measures to prevent breeding. Twice-a-week garbage collection is the minimum recommended frequency for adequate fly prevention. In many communities open dumps have been replaced by sanitary landfills that compact the daily dumping and cover it with soil. This method reduces odours and fly breeding. Daily compaction and twice-a-week soil cover is the minimum frequency for adequate fly control.

The primary cause of excessive fly breeding at animal farms is often poor water management. Poorly constructed effluent ditches and leaking watering systems is responsible for much of the wetting of manure that causes fly breeding. Any recommendations for fly control should give water management first priority for the permanent reduction of fly breeding. Proper grading of the land to ensure quick drainage during the rainy season is an important feature.

Regular removal of accumulated manure from outdoor animal pens should be practiced as a routine management feature, with particular emphasis on removal of dung under fence lines. Collected manure should be stored in cone-shaped piles; these piles reduce the surface area for breeding while the heat from fermentation makes the interior unsuitable for the flies. The outer surfaces of these piles dry quickly and tend to narrow the zone in which the larvae can develop. Wetting of old manure piles usually does not cause house fly breeding since they prefer fresh manure. The fact that the dog dung fly ( Musca sorbens) breed exclusively in fresh dung pats makes their control more difficult.

Dry manure is the most important thing to do so as to control the fly at poultry farms. Leaking watering systems should be repaired.
Daily washing of hog pens and adequate wash water lagoons greatly minimize fly breeding at hog farms. Breeding along effluent ditches can be eliminated by construction of concrete-lined ditches.
 

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