Musca autumnalis

The face fly Musca autumnalis occurs on cattle and sometimes horses around the world, including in Canada.


Summary

The face fly Musca autumnalis occurs on cattle and sometimes horses around the world, including in Canada.  Adult face flies are not blood-feeders but feed on oral, nasal and ocular secretions and on blood from the bites of other flies.  Eggs are laid in fresh cattle faeces, and it is here that the larvae and pupae develop prior to release of the adult flies.  The feeding activities of face flies can be a major nuisance, especially if present in large numbers.  They are also implicated in the transmission of the bacterium Moraxella bovis (the causative agent of infectious bovine keratoconjunctivitis or "pink eye") among cattle.

Taxonomy

Phylum: Arthropoda
Subphylum: Uniramia
Class: Hexapoda
Order: Diptera
Suborder: Cyclorhapha
Family: Muscidae

As well as the face fly, the Family Muscidae includes the house fly (Musca domestica), the horn fly (Haematobia irritans) and the stable fly (Stomoxys calcitrans). Male and female horn flies and stable flies blood feed on their hosts.

Note: Our understanding of the taxonomy of helminth, arthropod, and particularly protozoan parasites is constantly evolving. The taxonomy described in wcvmlearnaboutparasites is based on that in the seventh edition of Foundations of Parasitology by Larry S Roberts and John Janovy Jr., McGraw Hill Higher Education, Boston, 2005.

Morphology

Adult Musca autumnalis have a grey thorax with four dorsal longitudinal dark stripes and a brownish abdomen with a single, dorsal longitudinal dark stripe. They measure up to approximately 8 mm in length.

Host range and geographic distribution

Musca autumnalis affects primarily cattle and is found in North America, including Canada, Europe, Asia and parts of Africa.

Life cycle - direct

Adult male and female M. autumnalis are parasites of cattle and sometimes horses. They move about the face and eyes, feeding on ocular and nasal discharges, and also on blood from the bites of other flies. Adult face flies are strong fliers and can move easily among cattle, and even between farms.

The female face flies leave the host for a short time to lay eggs in freshly passed cattle feces. Under ideal conditions the eggs hatch in a day. There are three larval stages lasting approximately a week and the larva then produces a cocoon and pupates. After approximately one further week, the adult fly emerges from the pupa and quickly finds a new host. Thus there can be several generations of face flies in a summer.

Epidemiology

The life cycle of horn flies matches very well with that of their hosts and they are very successful on cattle in western Canada and in other parts of the world. Face flies over-winter primarily as adults in buildings, although in the summer they prefer to stay outside in the sun.

Pathology and clinical signs

Individual cattle may harbour many face flies and the movements and feeding of the flies can be very irritating and can adversely affect productivity. They may also aggravate wounds caused by other flies.

Musca autumnalis is the intermediate host for Thelazia species, a conjunctival nematode of cattle, and serves as an important mechanical vector for Moraxella bovis, the cause of "pink eye" in cattle.

Treatment and control

A large number of topical products, including ear tags, are approved in Canada for treatment and control of face flies on cattle. Some cannot be used in lactating dairy cattle. For help with face fly control in Canada, ear tags and topical products are available containing a variety of insecticides.

Detailed information on these products is available from the Compendium of Veterinary Products (CVP), (Twelfth Edition, 2011), or from the manufacturers. Use of the products is controlled by the Pest Conrol Products (PCP) Act.

 

Drug(s) Product(s)
Cypermethrin and Diazinon ELIMINATOR EAR TAGS
Diazinon PROTECTOR AND Y-TEX EAR TAGS
Lambda-cyhalothrin SABER EAR TAGS AND POUR-ON
Malathion CO-OP BACK RUBBER CONCENTRATE
Permethrin VARIOUS
Pyrethrins VARIOUS
Tetrachloviphos ENGAGE AND ECTOGARD CATTLE INSECTICIDE EAR TAGS

Public health significance

Although face flies will sometimes cause annoyance to people, especially those working with affected cattle, they are almost obligate parasites of cattle and so will feed on other hosts only very rarely.

References

Cortinas R et al. (2006) Ectoparasites of cattle and small ruminants. Veterinary Clinics of North America Food Animal Practice 22: 673-693.
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