<OL> <LI> Evaluate conventional and experimental poultry manure management systems as they influence production of filth flies, litter beetles and associated food-borne pathogens. <LI>Evaluate novel cultural, biological and chemical strategies for pest management to minimize nuisance and health risks in the rural-urban interface.
NON-TECHNICAL SUMMARY: House flies are pests of great medical and veterinary significance and one of the most successful animal species. House flies are synanthropic species and important nuisance pests of domestic animals and people as well as major vectors of food-borne and animal pathogens. Because of their indiscriminate movement, ability to fly, and attraction to places where food is prepared, house flies greatly amplify the risk of exposure to food-borne pathogens. House flies can transport microbial pathogens from reservoirs where they present a minimal hazard to people (animal manure), to places where they pose a great risk (food). This project will lead to a better assessment of the significance of flies as a potential link between agricultural and urban environment and their role in transmission of food-borne pathogens and antibiotic resistance genes. We know little about the changes in the properties of animal feces as these feces age and serve as larval media of pest flies. Because the feces properties make them to be aquatic environments, we must also consider fly larvae that develop on these feces to be aquatic organisms. Thus, the more we learn about the properties of animal feces as habitat of fly larvae and we learn about how these larvae deal with some of these limiting factors, the better we are prepared to conceive new control strategies based on control of filth flies at the larval stage. We propose to learn about the changes poultry feces undergo as they age, and relate the invasion by different fly larvae to the changes in feces properties.
APPROACH: Poultry manure is a main reservoir of some of the most important food-borne pathogens, including Campylobacter jejuni and C. coli. The ecology of Campylobacter spp. in the agricultural environment is not well understood. The goal of this project is to evaluate the prevalence and to characterize Campylobacter jejuni and C. coli from house flies (HF) (Musca domestica L.) collected from poultry farms. Live adult HF will be collected from poultry (chicken and turkey) farms and individually processed for isolation and characterization of campylobacters using CCDA medium, GasPack chambers and standard culturing protocols. Resistance assessment will be carried out on Muller-Hinton agar (BBL, MD) using diffusion disks with tetracycline, streptomycin, ampicillin, erythromycin, kanamycin, nalidixic acid, and ciproflaxacin. For identification, hip-gene (C. jejuni specific) and ceu-gene (C. coli specific) will be amplified by PCR. Genotyping will be conducted by RFLP of the flaA-gene. Construction of similarity matrix will be carried out with 2.5 BioNumerics (Applied Maths, Kortijk, Belgium). Normalized RFLP profiles will be compared using the Pearson product-moment correlation coefficient and clustered by the unweighted pair group method using average linkage (UPGMA). In addition, the prevalence, diversity, antibiotic resistance profiles of enterococci (the main reservoir of antibiotic resistance genes in the environment) from HF collected from poultry farms will be assessed by standard protocols. It has been demonstrated that cattle feces are invaded by different species of filth flies as the feces age. Likewise, several abiotic parameters, among them pH, osmolality, ammonia concentration, moisture and temperature, change during the aging process. Most of these abiotic factors are highly interrelated; thus, pH of these feces varies inversely proportional to the values of osmolality. Larvae of most of these filth fly species posses osmoregulatory organs, suggesting that these larvae have to contend with the osmotic pressures presented by these aquatic habitats. The understanding of the changes in the feces properties might lead to the devise of new methods of control of filth flies based on the effects these factors may have on fly larvae. Little is known about the phenology of pest fly immatures in poultry feces as these media age. Even less is known about the abiotic changes that take place in ageing poultry feces. To document changes that might occur in ageing poultry feces, these will be monitored as the feces age; additionally, filth fly species visiting feces as they age will also be monitored. Samples of poultry feces of different ages will be sampled and the values of the different parameters will be evaluated as follows: temperature by hand-held thermistor probes; pH with spear-tip pH electrodes; osmolality with a vapor pressure osmometer; ammonia with a specific electrode; and moisture gravimetrically. Attempts will be made in correlating size of the anal organ of different larval species and whether they are osmoregulators or osmoconformers.
PROGRESS: 2005/10 TO 2006/09<BR>
The ecology of Campylobacter spp. in the agricultural environment is not well understood. The goal of this study was to evaluate the prevalence and to characterize Campylobacter jejuni and C. coli from house flies (HF) (Musca domestica L.) collected from turkey farms. In total 553 live adult HF were collected from 16 turkey farms and individually processed for isolation and characterization of campylobacters. HF from 13 out of 16 farms tested positive; in total 121 HF (22%) carried campylobacters with prevalence ranging from 8 to 54% among flies from positive farms. Ninety one isolates were selected for further analysis including identification to species level by testing for hip-gene (C. jejuni) and ceu-gene (C. coli) by multiplex PCR; screening for antibiotic resistance to seven antibiotics by disk diffusion technique, and genotyping by restriction fragment length polymorphism (RFLP) of the flaA-gene. Forty seven (52%) isolates represented C. jejuni and 44 isolates (48%) were C. coli. Many isolates were resistant to all antibiotics, including kanamycin (83% of isolates), ampicillin (82%), tetracycline (79%), ciproflaxacin (68%), streptomycin (62%), nalidixic acid (66%), and erythromycin (39%). No differences were detected between C. jejuni and C. coli with the exception of resistance to erythromycin where 100% of C. jejuni isolates were sensitive to erythromycin while 85% of C. coli were resistant. Genotyping revealed 18 different genotypes; HF from majority of individual farms either carried campylobacters of the same genotype or a dominant one. Five genotypes were detected from multiple (two to four) farms. These data show that house flies commonly carry antibiotic resistant C. jejuni and C. coli and likely play an important role in dissemination of these bacteria among farms and possibly from farms to the urban environment.
IMPACT: 2005/10 TO 2006/09<BR>
Campylobacteriosis is a leading food-borne diarrhoeal disease in developed countries, including the United States. Although 15 Campylobacter species have been described, two of those, C. jejuni and C. coli, account for over 95% campylobacter infections in humans. Majority of human infections are caused by consumption of contaminated food of animal origin though cases of illness from consumption of contaminated raw milk and untreated water have been also reported. In most industrialized countries, the route of majority of human infections is believed to be a consumption of contaminated and undercooked poultry. Birds, primarily chicken and turkeys, are considered the primary reservoir of C. jejuni. Despite numerous studies on campylobacters, the ecology and transmission of C. jejuni and C. coli among poultry flocks and among farms are poorly understood. Our study shows that house flies likely play an important role in the ecology and dissemination of C. jejuni and C. coli.