M.F. Mul

Prevalence and key figures for the poultry red mite Dermanyssus gallinae infections in poultry farm systems

Recent surveys and sample collection have confirmed the endemicity of Dermanyssus gallinae in poultry farming worldwide. The reduction in number and efficacy of many acaricide products has accentuated the prevalence rates of this poultry ectoparasite observed more often in non intensive systems such as free-range, barns or backyards and more often in laying hens than in broiler birds. The lack of knowledge from producers and the utilisation of inadequate, ineffective or illegal chemicals in many countries have been responsible for the increase in infestation rates due to the spread of acaricide resistance. The costs for control methods and treatment are showing the tremendous economic impact of this ectoparasite on poultry meat and egg industries. This paper reviews the prevalence rates of this poultry pest in different countries and for different farming systems and the production parameters which could be linked to this pest proliferation.

Preventing introduction and spread of Dermanyssus gallinae in poultry facilities using the HACCP method

Preventing the establishment of ectoparasitic poultry red mite (Dermanyssus gallinae) populations is key in ensuring welfare and egg production of laying hens and absence of allergic reactions of workers in poultry facilities. Using the Hazard Analysis and Critical Control Point method, a panel of experts identified hazards and associated risks concerning the introduction and spread of this mite in poultry facilities. Together we provide an overview of possible corrective actions that can be taken to prevent population establishment. Additionally, a checklist of the most critical control points has been devised as management tool for poultry farmers. This list was evaluated by Dutch and British poultry farmers. They found the checklist feasible and useful.

Validation of an automated mite counter for Dermanyssus gallinae in experimental laying hen cages

Abstract For integrated pest management (IPM) programs to be maximally effective, monitoring of the growth and decline of the pest populations is essential. Here, we present the validation results of a new automated monitoring device for the poultry red mite (Dermanyssus gallinae), a serious pest in laying hen facilities world-wide. This monitoring device (called an “automated mite counter”) was validated in experimental laying hen cages with live birds and a growing population of D. gallinae. This validation study resulted in 17 data points of ‘number of mites counted’ by the automated mite counter and the ‘number of mites present’ in the experimental laying hen cages. The study demonstrated that the automated mite counter was able to track the D. gallinae population effectively. A wider evaluation showed that this automated mite counter can become a useful tool in IPM of D. gallinae in laying hen facilities.

Actinobacillus pleuropneumoniae is impaired by the garlic volatile allyl methyl sulfide (ams) in vitro and in-feed garlic alleviates pleuropneumonia in a pig model

Decomposition products of ingested garlic are to a certain extent excreted via the lungs. If the supposed health-supporting capacities associated with garlic extend to these exhaled sulfurous compounds, they could have an effect on the course of pneumonia. In this study, the garlic-derived volatile allyl methyl sulfide (AMS) as a lead compound of volatile garlic metabolites was shown to exhibit an antibacterial effect against the pig pathogen Actinobacillus pleuropneumoniae serotype 9. AMS caused a delay in the appearance of the optical density-monitored growth of A. pleuropneumoniae in medium when compared to unaffected growth curves, yet without lowering the stationary phase yield at the concentration range tested. At 1.1mM, AMS impaired the in vitro growth rate of A. pleuropneumoniae serotype 9 by 8% compared to unimpeded growth. In an animal trial, a garlic-fed group of 15 pigs that received a diet with 5% garlic feed component and a control group of 15 pigs that received a diet without garlic were infected with A. pleuropneumoniae serotype 2 via an aerosol and subsequently followed for 4 days. At the day of the challenge, blood AMS in the garlic-fed group amounted to 0.32 ± 0.13 μM. A beneficial, alleviating effect of garlic on the course and severity of an A. pleuropneumoniae infection in pigs was indicated by the reduced occurrence of characteristic pleuropneumonia lesions (27% of the lungs affected in the garlic-fed group vs. 47% in the control group) and a near to significant (p=0.06) lower relative lung weight post mortem in the garlic-fed group.

Dermanyssus gallinae in Dutch poultry farms: Results of a questionnaire on severity, control treatments, cleaning, and biosecurity

In 2005 a questionnaire has been sent to 1,390 Dutch poultry farmers to investigate the severity of the poultry red mite (PRM) as a pest problem in The Netherlands. The response rate amounted to 31%. As the questions were not independent of each other, four clusters of questions were formed, based on two observed, discrete variables: (1) directly visible PRM infestation, and (2) indirect signs of the presence of PRM. Respondents were distributed over the most common housing systems in The Netherlands and reflected the Dutch situation with regards to housing of laying hens quite well. More than 80% of the poultry farmers reported infestations of PRM. Chicken flocks without PRM problems were significantly younger than flocks where (signs of) PRM infestation were observed. Where poultry was housed in battery cages, more farmers reported problems with PRM infestations, they tend to apply the first control treatment earlier, and repeat it more often than farmers with poultry in other housing systems. When PRM or signs of PRM were reported, farmers more often applied a combination of control treatments. The mean costs paid for control treatments and the costs incurred in terms of production losses were estimated to be € 0.43 per hen in an average flock. Given that there are 300 million layer hens in Dutch poultry houses and that ca. 85% of the flocks are PRMinfested, the overall annual cost to the national poultry industry is estimated at € 11 million. Since the answers to the questionnaire revealed a significant underuse of several measures that could prevent PRM infestation, there is room for improvement by more stringent management.

Control of Salmonella at pig finishing farms with a farm decision tree

To decrease the prevalence of Salmonella in the Dutch pork chain a management tool is developed based on the HACCP methodology (Hazard Analysis of Critical Control Points) and tested at three pig farms on effectiveness and practical feasibility. A so called HACCP team defined Critical Control Points (CCP) and general measures. For all identified CCP’s corrective actions are determined. Based on the obtained knowledge eight decision trees are designed and applied at three pig farms during eight months. The finishing pigs were tested bacteriologically and serologically every 2-3 month on Salmonella typhimurium. At one farm the number of positive samples declined over time. The other two farms showed a low prevalence during the entire trial period, even though all farms had a high prevalence in august 2001. It can be concluded that the decision trees are useful to determine weak points and to advice specific control measures to prevent or reduce Salmonella in pig farms.