Flies are not just a nuisance; they carry diseases which pose a serious health hazard to people and animals. Globally, they cause livestock and poultry production losses estimated in the billions of dollars.
Non-biting flies feeding on secretions from the eyes, nose and any small wounds. This distracts animals from grazing, causing a reduction in growth and productivity.
Non-biting flies are not key vectors of any specific disease organisms, but because of their feeding and reproduction habits, and the structure of their feet and mouthparts, they can act as mechanical vectors for a whole range of pathogens, from viruses to helminthes. All told, they are known to be involved in the transmission of more than 65 diseases to humans alone, including typhoid fever, dysentery, cholera, poliomyelitis, yaws, anthrax, tularemia, leprosy and tuberculosis (Greenberg, 1965).
Biting flies can cause even greater irritation to domestic animals, and they too are vectors for disease transmission. However, because they feed on blood, they can also cause anemia and hypersensitivity.
The growth and performance of nearly all farmed animals are adversely affected by flies, especially when they are present in high numbers. Infested animals become harassed and feed intake is drastically reduced (Stork, 1979). The result: significant reductions of meat, milk and egg production and serious economic losses.
Whenever fly populations reach plague proportions in locations close to human habitation, they represent a serious health and environmental hazard - not just to the farmer, but to neighbors and local communities. Social and regulatory pressure will doubtless increase in the future, leading to the possible closure of farms by local health authorities.
The major diseases transmitted by flies to humans and domestic animals are enteric diseases and eye infections. Flies also play an important role in the epidemiology of mastitis in cattle. Various other infections and several parasitic diseases can also be carried and spread by flies. Further information about the major diseases carried by flies is available by clicking on the links below:
