Prevalance of the Red Mite Problem

Prevalence across Europe

The prevalence and key figures for the poultry red mite, Dermanyssus gallinae infections in poultry farming systems was covered by Dr Olivier Sparagano from the University of Newcastle in the UK, presenting a project that involved ten research centres across Europe. He explained that the mites are blood feeders and are responsible for anaemia and welfare problems in birds, dermatitis in humans and egg downgrading and blood spotting which imply a huge economic, welfare and epidemiological problem for birds and human populations. Furthermore red mites have been suspected and identified as a vector for some other pathogens bringing more animal health issues.

On average, the infestation rate was between 60 and 65 per cent for cage, free-range and organic systems while it was around 54 per cent for barn production systems, said Dr Sparagano. However prevalence rates were variable between countries and between poultry production systems and control methods would depend of the mite status in individual countries, he said.

The data shows the endemic situation with red mites, and the need to control them. Ventilation, dust levels, acaricide misuse and repopulation cycles seem to have had an impact on the mite development in poultry farms, Dr Sparagano concluded.

Prevalance in southern Italy

A poster by Camarda and others described a prevalence study on red mites on laying hen farms in southern Italy. A questionnaire was sent to all intensive layer farms in the region of Apulia, requesting information about the farm (size, housing type, and building age), the farmers (education level, and their perception of the problems related to red mite infestation), and management practices (methods of red mite control, frequency of treatment and timing).

Out of 58 poultry farms visited, 43 (74 per cent) farms were found to be infested by red mites, with a prevalence of 92 per cent on small farms. Just over half of all farmers reported that their farms had an infestation, and 74 per cent regularly use acaricides to control the mites.

The researchers say that red mites are widely present in battery hen units in Apulia, with a very high prevalence compared to other European countries. Poor hygiene and the continuous use of the houses contribute to high infestation, and they warn that the application of home-made chemicals and the widespread use of acaricides may enhance resistance.

Types of red mite found in Europe

In an oral paper, M. Marangi of the University of Foggia in Italy presented the phylogenetic relationship between red mite populations in the UK, France and Italy based on mitochondrial CO1 gene sequences.

Samples from UK farms showed more variation than those from France or Italy. Interestingly, the UK populations were linked to one of the French population, highlighting North-South genetic transitions in European red mite populations. There was also variation within farms. The authors suggest that populations reflect the different chemical strategies used in each country.

After studying the red mite populations on layer farms in France, L. Roy of the National Veterinary School in Lyon found that the mitochondrial gene showed a high degree of homogeneity – more so than other European countries. The fact that all the red mite lineages found on layer farms were closely related suggests that there might have been some adaptive evolution processes allowing these mites to infest farms and that their spread might be correlated to commercial flaws. Roy and colleagues reported almost no exchanges of red mites between wild and domestic birds.

Monitoring Red Mites

Dr Monique Mul of Wageningen University Research in the Netherlands described how the HACCP (Hazard Analysis and Critical Control Points) method can be used to prevent the introduction and spread of red mites on poultry farms. The fourth aspect of HACCP – establishing critical control point monitoring requirements – was the focus of her oral paper. She explained that red mite infestations are mostly noticed when farmers or workers are bitten, mites are seen on the belt and feeders, clumped mites are seen or when blood spots on eggs are present.

Effective and easy applicable monitoring methods are necessary to monitor flocks for the presence of mites as well as a subsequent quick response, she said. One method successfully used for monitoring and to make farmers more aware of the problem in the Netherlands has involved using PVC tubes provided with a wooden stick as an attractive hiding place for mites.

Methods of Red Mite Control

Currently, acaricides are the main method of controlling red mites on commercial farms but there are concerns that the mites are growing resistant to carbamate, organophosphorus, amidine and pyrethroid-based acaricides, and new methods of control are being developed.

Use of acaricides

Using a field population of red mites from Italy, M. Marangi's poster described the evaluation of the susceptibility of the red mite to selected acaricides. They tested five different acaricide concentrations (5, 10, 20, 50 and 100 per cent) plus an untreated control (0 per cent). Amitraz showed an efficacy of 100 per cent on six of the seven farms tested, while carbaryl was only effective on one of the farms, and then only at 100 per cent concentration. The efficacy of permethrin was good (from 95 to 100 per cent) on only one farm and only at the two highest concentrations.

The researchers concluded that the field red mite populations were found to be tolerant even with the highest concentrations with carbaryl and permethrin for 86 per cent and 42 of the investigated farms, respectively. Most of the farms (86 per cent) had a red mite population susceptible to amitraz at any concentration but one was already showing signs of the development of resistance to this chemical.

Heat treatment

Monitoring methods and treatments were described in a poster by Maika Cox of the Provincial Centre for Applied Poultry Research in Antwerp, Belgium and others there and at the University of Wageningen.

During several laying periods red mite infestation was monitored using the MMS, Mite Monitoring Score, a method based on regular checks of different places in the housing system. Depending on the score, treatment was carried out and therefore different products were used and evaluated.

The best results were obtained using silica products, which resulted in controlling the infestation at an acceptable level, they found. A new treatment involves heating the house to approximately 42°C on the ground before arrival of the birds. This, combined with a low relative humidity, destroys the mites and dries out the eggs. It helped to prolong the mite-free period in early trials.

A future for vaccines

An in vitro feeding assay to test the protective effects of poultry red mite antigens was presented by Dr Harry Wright of the Moredun Research Institute in Scotland. The researchers hypothesised that the antigens may have potential as vaccine candidates, and they found that the strongest anti-mite effect was seen against the PBS-soluble protein fraction.

Further results from the same institute were presented by Dr Kathryn Bartley, who described the potential of cathepsin proteases as vaccines for the control of red mite infestations in commercial poultry houses.

New Evidence That Red Mites Transmit Pathogens

A poster by C. Moro of the Laboratory 'Microorganismes: Génome et Environnement in Aubière in France and others demonstrated that the poultry red mite can act as a biological vector for Salmonella Enteritidis. The group has also detected E. coli, Shigella, Staphylococcus and Stenotrophomonas matophilia alive on or in this poultry pest. For the symbionts, bacteria of the genera Cardinium, Spiroplasma, Rickettsiella and Schineria have also been identified living inside the red mite.

References

Bartley K., A. Nisbet, H. Wright and J. Huntley. 2009. Cathepsin proteases: their potential as vaccines for the control of Dermanyssus gallinae infestations in commercial poultry houses. Proceedings of 8th Poultry Welfare Symposium, Cervia, Italy, 18-22 May 2009, 78.

Camarda A., E. Circella, M. Marangi, A. Giangaspero, O.A.E. Sparagano, G. di Paola, D. Galante and M.A. Cafiero. 2009. A prevalence study on Dermanyssus gallinae in laying hen farms in Southern Italy. Proceedings of 8th Poultry Welfare Symposium, Cervia, Italy, 18-22 May 2009, 82.

Cox, M., K. de Baere, E. Vervaet, J. Zoons and T. Fiks-van Nierkek. 2009. Red mites: monitoring method and treatment. Proceedings of 8th Poultry Welfare Symposium, Cervia, Italy, 18-22 May 2009, 83.

Marangi, M., M.A. Cafiero, G. Capelli, A. Camarda, O.A.E. Sparagano, C. Venturelli and A. Giangaspero. 2009. Evaluation of the poultry red mite (Dermanyssus gallinae, Acarina:Dermanyssidae) susceptibility to some acaricides in a field population from Italy. Proceedings of 8th Poultry Welfare Symposium, Cervia, Italy, 18-22 May 2009, 85.

Marangi M., C.J. de Luna, M.A. Cafiero, A. Camarda, S. Le Bouquin, A. Giangaspero and O.A.E. Sparagano. 2009. Phylogenetic relationship between Dermanyssus gallinae populations in European countries based on mitochondrial CO1 gene sequences. Proceedings of 8th Poultry Welfare Symposium, Cervia, Italy, 18-22 May 2009, 76.

Moro, C.V., C.J. de Luna, A. Tod, J.H. Guy, L. Zenner and O.A.E. Sparagano. 2009. Pathogens and symbionts associated with Dermanyssus gallinae: risks and potential control methods for the poultry industry. Proceedings of 8th Poultry Welfare Symposium, Cervia, Italy, 18-22 May 2009, 86.

Mul, M. 2009. Using the HACCP method for preventing introduction and spread of Dermanyssus gallinae in poultry facilities with a focus on monitoring methods. Proceedings of 8th Poultry Welfare Symposium, Cervia, Italy, 18-22 May 2009, 79.

Roy, L., S. Lubac, N. Guichard, M. Rigaux, C. Chauve and T. Buronfosse. 2009. Populations of D. gallinae infesting French layer farms show a strong homogeneity in mt-Co1 sequences, if compared with some other populations. Proceedings of 8th Poultry Welfare Symposium, Cervia, Italy, 18-22 May 2009, 87.

Sparagano, O.A.E., A. Pavlievi, T. Murano, A. Camarda, H. Sahib, O. Kilpenin, M. Mul, R. van Emous, S. Le Bouquin, K. Hoel and M.A. Cafiero. Prevalence and key figures for the poultry red mite Dermanyssus gallinae infections in poultry farm systems. Proceedings of 8th Poultry Welfare Symposium, Cervia, Italy, 18-22 May 2009, 75.

Wright, H.W., K. Bartley, A.J. Nisbet, R.M. McDevitt, N.H.C. Sparks, S. Brocklehurst and J.F. Huntley. 2009. In vitro feeding assay to test the protective effects of poultry red mite antigens. Proceedings of 8th Poultry Welfare Symposium, Cervia, Italy, 18-22 May 2009, 77.

Further Reading

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You can see other papers presented at the 8th European Symposium on Poultry Welfare by clicking here.