Fly Control for Biosecurity in Poultry Farms

By Mike Catangui, Ph. D |

Flies are vectors of disease-causing microorganisms
A group of chickens in a poultry house

House flies (Musca domestica) are important in public health because they can vector many species of disease-causing bacteria, viruses, helminths and protozoans to humans. Because human disease-causing microorganisms can originate from livestock, farm-level house fly control programs are mainly designed and implemented to prevent potential local and outward fly migration and disease transmissions from the farm to nearby human establishments and population centers. Thus, the U.S. Food and Drug Administration closely monitors house fly populations in egg-producing chicken farms to prevent Salmonella Enteritidis infections in humans (USFDA, 2011).

Fly
Fig. 1. An adult house fly (Musca domestica).
A table of poultry diseases that can be vectored by house flies

Equally important, however, is the ability of house flies to transmit disease-causing microorganisms originating from outside the poultry house into healthy chickens and turkeys. And there are times, such as right now, when we have to worry about house flies transmitting potentially devastating poultry diseases that can impact all production phases of susceptible turkeys, egg-laying hens and broiler chickens. There are currently no published studies that show house flies can vector the highly pathogenic avian influenza H5N2 virus in poultry in the United States. However, house flies have been shown to be competent vectors of the highly pathogenic avian influenza subtype H5N1 virus in chickens in Thailand (Wanaratana et al., 2013). And because of the long list of disease-causing microorganisms that house flies can vector, and the lag time before formal scientific studies can be conducted and published (if ever), house flies will need to be controlled right now to minimize the risk of probable avian influenza H5N2 disease transmissions by house flies into poultry houses. Table 1 presents serious diseases of poultry that can be vectored by house flies.

Flies are efficient vectors of diseases

The biology and behavior of house flies make them an efficient vector of diseases. The house fly [Fig. 1] is a very common insect pest in U.S. poultry production and processing facilities. They alight and feed on the bodily secretions and excretions of poultry, and on the feed and water provided to these farm animals. House flies occur year round on the farm; they can breed and multiply outdoors and indoors during the summer, and mostly indoors during the winter. During the spring and summer months, house flies may pick up disease-causing microorganisms from sources outside the barn (e.g., droppings from wild or migrating birds from nearby wetlands), then bring them inside the barns to start the infection process. House flies are notorious for depositing “fly specks” or regurgitated stomach contents and feces on surfaces wherever house flies feed and roost. These “fly specks” may be laden with disease-causing microorganisms. The number of “fly specks” [Fig. 2] on the walls and ceilings of the barn is usually proportional to the number of
active house flies in the area.

“Fly specks” or regurgitated stomach contents and feces deposited by house flies on a transparent surface.
Fig. 2. "Fly specks" or regurgitated stomach contents and feces deposited by house flies on a transparent surface.

House flies can disperse to far distances. Most adult house flies stay within two miles of their breeding sites but some can migrate to up to 20 miles away (Murvosh and Taggard, 1966). It is also well known that house flies can “hitch a ride” in pickup trucks and other animal transport vehicles. In this manner, infected house flies can potentially disperse to clean sites several hundred miles away from the source.

Fly control products

Effective and economical fly control products are available to poultry producers. There are several effective and relatively inexpensive house fly insecticides to choose from [Tables 2-5]. House fly baits can be scattered in strategic exterior and interior areas of poultry houses to lure and kill house flies [Table 2]. Liquid or “sprayable” baits are also available for application on vertical surfaces or areas where solid baits are not practical. For immediate reduction in house fly numbers, poultry can be sprayed directly with insecticides that have “on-animal” labels [Table 3]. These “on-animal” sprays are quick-knockdown house fly insecticides with shorter residual action. During barn clean out, or when the birds are not in the barn, insecticides with longer residual effects can be applied on the surfaces of the empty barn where house flies will tend to congregate once the birds are placed inside. Empty-barn residual sprays [Table 4] can provide months of residual house fly control. Although the barns need to be empty of chickens or turkeys to safely treat with residual insecticides listed in Table 4, the birds can be placed immediately in the treated barns once the spray has dried out. For a more complete and longer lasting fly control program, the larval or maggot stage of the house fly can be treated in their breeding sites with effective larvicides [Table 5]. Lastly, because insecticide application equipment can greatly influence the efficacy and efficiency of any fly control program, poultry growers are encouraged to consider the recommended equipment listed in an articled entitled “Spray, mist or fog: Get to know your insecticide application equipment” (Catangui, 2019).

A table of house fly baits for use in and around poultry houses
+ Enlarge Prior to using any product mentioned in this article, carefully read and follow all available instructions, warnings and safety information made available by the product’s manufacturer. ** Restricted use insecticide in AK, IN, MI, and VT.
On-animal sprays for house fly control in poultry
+ Enlarge Prior to using any product mentioned in this article, carefully read and follow all available instructions, warnings and safety information made available by the product’s manufacturer. *Restricted use insecticide.
Empty-barn residual sprays for poultry houses
+ Enlarge Prior to using any product mentioned in this article, carefully read and follow all available instructions, warnings and safety information made available by the product’s manufacturer. *Restricted use insecticide.
House fly larvicides for use in poultry houses
+ Enlarge Prior to using any product mentioned in this article, carefully read and follow all available instructions, warnings and safety information made available by the product’s manufacturer. *Restricted use insecticide.
Literature Cited:
Calibeo-Hayes D., S.S. Denning, S.M. Stringham, J.S. Guy, L.G. Smith, and D.W. Watson. 2003. Mechanical transmission of turkey coronavirus by domestic houseflies (Musca domestica Linnaeaus). Avian Diseases 47:149- 153.
Catangui, M. A. 2019. Spray, mist or fog: Get to know your insecticide application equipment. Producer Outlook, Spring-Summer 2019. MWI Animal Health.
Murvosh, C. M., and C.W. Taggard. 1966. Ecological studies of the housefly. Annals of the Entomological Society of America 59:534–547. Spindler, L. A. 1967. Experimental transmission of Histomonas meleagridis and Heterakis gallinarum by the sow-bug, Porcellio scaber, and its implication for further research. Proceedings of the Helminthological Society of Washington 34: 26-29.
United States Food and Drug Administration [USFDA]. 2011. Guidance for industry: prevention of Salmonella Enteritidis in shell eggs during production, storage,and transportation (https://www.fda.gov/media/82653/download).
Wanaratana, S., A. Amonsin, A. Chaisingh, S. Panyim, J. Sasipreeyajan, and S. Pakpinyo. 2013. Experimental assessment of houseflies as vectors in avian influenza subtype H5N1 transmission in chickens. Avian Diseases 7:266-272.

About the Author

Dr. Mike Catangui

Mike Catangui, Ph. D

Entomologist, Parasitologist
MWI Animal Health
Dr. Catangui is a member of MWI's Technical Services groups. As a team, this group provides our clients with targeted expertise in integrated pest management, proactive disease/pathogen and performance management, animal drinking water quality improvement, biosecurity, and cleaning and disinfection. 
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