AN EXAMPLE OF RATIONAL DERMANYSSUS GALLINAE CONTROL – PULCAP

Th e irrational control of Dermanyssus gallinae ectoparasites (De Geer, 1778) in intensive livestock can cause health problems, economic damage, and can also toxicologically harm the health of humans and the environment. Formulation P 547/17 (Pulcap) is a new generation of inert matter (an oil). In Pulcap formulation and technology, the fulfi lment of rigorous criteria for rational control of D. gallinae were tested and present in this paper. Th ose criteria are the following: the safety of the preparation (i.e. the preparation is non-toxic); the feasibility of application of the preparation in facilities, for handling transport cages, on used cages and equipment, as well as in inhabited buildings; the method of application the preparation is applied by spray method (external application). Th e aim of the application was also considered. It is to make the control eff ective, on the condition that eradication is feasible. Th en, the conditionality, which imply that the application of this preparation requires fulfi lling hygienic conditions, break of production in facilities, a certain temperature and professional approach to it. Th e effi cacy of the preparation is another important criterion. It implies that the clinical results of the application have been monitored in diff erent conditions at diff erent time intervals. It has been proven that there is no resistance to this preparation. Th e disadvantages of the preparations were also observed. It is the absence of prolonged action on absorbent surfaces, the delay in starting the egg bar and discharging, which increases contamination. Th e whole program / plan of long-term control has been developed. Th e cost-eff ectiveness of the product is the ratio of price and effi ciency on an annual level. Eradication is the most economical method of controlling D. gallinae, which relieved farmers from all further costs. Th ere is a great 1* Corresponding author: zemljadrveca@gmail.com Arhiv veterinarske medicine, Vol. 12, No. 1, 71 85, 2019 Pavlićević, A. ... et al.: An example of rational... 72 challenge for each type of D. gallinae control, especially the rational one. Reconsidering and further development of the approach of rational control is a way to improve the control of D. gallinae, which we want to encourage.


Abstract
Th e irrational control of Dermanyssus gallinae ectoparasites (De Geer, 1778) in intensive livestock can cause health problems, economic damage, and can also toxicologically harm the health of humans and the environment. Formulation P 547/17 (Pulcap) is a new generation of inert matter (an oil). In Pulcap formulation and technology, the fulfi lment of rigorous criteria for rational control of D. gallinae were tested and present in this paper. Th ose criteria are the following: the safety of the preparation (i.e. the preparation is non-toxic); the feasibility of application of the preparation in facilities, for handling transport cages, on used cages and equipment, as well as in inhabited buildings; the method of application -the preparation is applied by spray method (external application). Th e aim of the application was also considered. It is to make the control eff ective, on the condition that eradication is feasible. Th en, the conditionality, which imply that the application of this preparation requires fulfi lling hygienic conditions, break of production in facilities, a certain temperature and professional approach to it. Th e effi cacy of the preparation is another important criterion. It implies that the clinical results of the application have been monitored in diff erent conditions at diff erent time intervals. It has been proven that there is no resistance to this preparation. Th e disadvantages of the preparations were also observed. It is the absence of prolonged action on absorbent surfaces, the delay in starting the egg bar and discharging, which increases contamination. Th e whole program / plan of long-term control has been developed. Th e cost-eff ectiveness of the product is the ratio of price and effi ciency on an annual level. Eradication is the most economical method of controlling D. gallinae, which relieved farmers from all further costs. Th ere is a great

CRITERIA FOR RATIONAL D. gallinae CONTROL
According to the World Health Organization (WHO), rational pharmacotherapy requires that "patients receive medications appropriate to their clinical needs, in doses that meet their own individual requirements, for an adequate period of time, and at the lowest cost to them and their community". Based on the general defi nition and specifi c demands of this issue, we propose the following criteria for rational D. gallinae control: 1. 1. Safety 2. Feasibility of application 3. Time of application: preventive or curative approach 4. Method of application 5. Aim of application: suppression or eradication 6. Necessary conditions 7. Effi cacy: laboratory and clinical 8. Resistance and other adaptive mechanisms 9. Disadvantages 10. Long-term and comprehensive control plan: the program 11. Cost-eff ectiveness Th e P 547/17 formulation (Pulcap) is a new generation of inert substances, which is applied in the form of water emulsion. It is registered as a product for general use. Th e criteria of rationality regarding Pulcap formulation and technology are the following:

Safety
Synthetic, neurotoxic chemical compounds -acaricides or insecticides are the predominant type of D. gallinae control. Th e fi rst problem with these compounds is their potential toxicity to humans, animals and the environment.
Unlike insecticides, Pulcap formulation falls into the category of non-toxic compounds. In addition to this, its application focuses on the poultry housing preparation, which prevents any kind of exposure or stress. Only in cases when the necessary conditions have not been met, application is suggested with the poultry inside. In this situation, the formulation's effi cacy helps to avoid excessive use. Pulcap formulation and technology fulfi ls the highest safety criteria.
In general, herbal products are an appropriate choice regarding safety. Th e safety of SiO2-based products depends on the content of a specifi c formulation and on the application technology itself.

Feasibility of application
Pulcap formulation is applied in the preparation of (empty, cleaned and disinfected) poultry houses, treatment of poultry transport cages, and treatment of used cages and equipment (Fig 1). If necessary, it can be used in a full house, with poultry inside. Veterinary medicine fl uraraner (Exzolt) can be used only for the treatment of poultry, while other insecticides for external use can also be used for housing preparation. Rational application of insecticides on transport cages is problematic due to very demanding conditions for the detection of resistance. Th e situation is similar with used cages and equipment -if the examination for resistance is not performed on the infested fl ock before the placement.
Selected SiO 2 formulations (combination of powder and liquid form), can be a good choice for housing preparation if the necessary conditions have been met. Th ey are also used in production with a signifi cantly lower eff ect (Fig 2). Th ey are not appropriate for application on plastic transport cages, while the treatment of used cages and equipment depends on a specifi c situation. Herbal formulations are prepared primarily for the application through poultry's feed and water.

Time of application: preventive or curative approach
Th e current concept of application of insecticides and herbal formulations is based on the curative approach. As opposed to this, Pulcap is based on the preventive action, during pre-placement housing preparation (Fig 3). Th e preventive approach should be chosen because of the following: it prevents exposure (of poultry, eggs, staff ) and ensures the safety of the procedure; it maximizes the eff ect; it prevents damage; it prevents the transmission of D. gallinae; it prevents the spreading and development of the disease; it decreases the possibility of resistance development; it is cost-eff ective; and the fl ocks are treated only if necessary. Th e treatment of the fl ock as the primary concept of D. gallinae control is wrong, because it can be successfully prevented (avoided). Instead of biosecurity measures, farmers are off ered Q -Perch Vencomatic equipment for active D. gallinae control (van de Ven, 2016).

Method of application
Th e correct application technology (D. gallinae control has been focused only on products) has in most cases been missing in practice so far, thus signifi cantly contributing to the existing negative tendency of Dermanyssosis. Timely procedure and comprehensive and systematic application are necessary.
External application by spraying is the most common method of application. Compared to this, per os application has an advantage because it is simple to perform, but at the same time, it is much more complicated regarding safety (which is a much more important criterion), since the formulation is incorporated directly into the poultry's body and, thus, into human food.
Machine application technology has been developed for Pulcap formulation. It includes mounting a structure with nozzles, which systematically applies the water emulsion on the targeted places. Th is way, a high operability is enabled and three persons can treat the capacity of up to 100,000 layers in the cage system per day (Fig 4). At the ends of batteries, in small farms and other types of layer housing, manual application can be implemented.

Necessary conditions
Application of Pulcap technology requires hygienic conditions, housing downtime (14 days or longer for eradication), temperature above freezing, and professional application. Other approaches in D.gallinae control have similar requirements and conditions (to a greater or lesser extent). Th e essence of the problem is that most oft en conditions and requirements are not suffi ciently specifi ed nor is abiding by them emphasized enough.

Effi cacy
Laboratory tests provide important, but limited guidelines for the biological effi cacy against D. gallinae. It is very important for insecticides to have specifi cation for a concrete infestation and to be based on up-to-date information. Resistance development has eliminated most of the insecticides used so far, so a lot of older data on effi cacy testing is no longer relevant. Th e latest insecticide is fl uralaner (Exzolt). It is used to treat poultry and is applied through drinking water twice over a period of 7 days. Acaricide effi cacy of fl uralaner applied in this way over 15 days is between 99.3% and 100% (Brauneis et al., 2017). It is estimated that this veterinary medicine achieves suppression of over 90% in an average period of 8 months (56 -238 days) (Th omas et al., 2017).
Th e effi cacy of diff erent SiO2-based formulations varies signifi cantly (Maurer et al., 2009;Schulz, 2014;Pavlićević et al., 2018c). For this reason it is necessary to choose the formulation based on effi cacy tests. Moreover, SiO2based formulations have extremely demanding application, small acaricide capacity per surface unit and slow eff ect, so even the lethally exposed mites can lay fertile eggs. Th eir action is aff ected by dirt and humidity (Pavlićević et al., 2017(Pavlićević et al., , 2018b. Th eir application is optimized in the control program, by combined application of powder and liquid forms in an empty poultry house and with housing downtime in the temperature conditions when mites are active (Pavlićević et al., 2017(Pavlićević et al., , 2018b. Th e most important disadvantages of SiO2-based formulations are eliminated by the new generation of inert substances -Pulcap. It is a water emulsion of inert oils, it has good applicability, distribution, a quicker eff ect on the exposed D. gallinae, higher mortality per surface unit, and extremely long prolonged eff ect on unabsorbent surfaces. Clinical results with all the conditions fully met, aft er the application of 20% Pulcap water emulsion, were negative in 8 poultry houses with cage rearing system (a total capacity of 144,000 chicks) during 6 months, over the period aft er rearing two fl ocks in each (the observation is ongoing) (Fig 5). Another example was in partly met conditions in 7 poultry houses with the capacity of 241,360 layers, in a cage system (conventional and enriched). In addition to the housing preparation with 20% Pulcap water emulsion, over the production period of one year, another treatment with 10% water emulsion was necessary. In three houses with the total capacity of 103,000 hens, only one preparatory treatment was suffi cient for the suppression eff ect over the production period of one year. However, in cases when conditions were fully met, there are examples of complete eradication from the production facilities (so far confi rmed in 2 houses with conventional cage system, a total capacity of 6,000 hens). In the case of application in a full house, one treatment with 10% Pulcap water emulsion provides 3 to 4 months of suppression on average. However, two consecutive treatments increase the effi cacy in a full house (up to 5-10 months, according to the experience so far). Based on the recorded results, Pulcap technology belongs to the effi cient methods of D. gallinae control. Nevertheless, we believe that the technology has not been optimized yet and that even higher effi cacy than the one recorded so far can be achieved. Optimization tests are ongoing, and the results are expected by the end of 2020. During and aft er the application of phytorepellents, feeding and reproduction of D. gallinae were reduced (Puvača et al., 2016). Th e problem is that the number of mites per hen still increases over time, so the numbers neutralize the positive eff ect achieved so far. In addition to this, as a result of the application of phytorepellents on poultry, the mites increasingly attack farm staff . Due to the (signifi cant) lack of cidal or real repelling eff ect (which would stop the reproduction completely), phytorepellents are actually only partial repellents. Such characteristics qualify them primarily as an auxiliary product in D. gallinae control. A good choice of this product can be justifi ed if it is necessary to maintain a tolerable, cost-eff ective level of infestation at the end of the fl ock's production period, until the fl ock is removed from the house.

Resistance and other adaptive mechanisms
Another problem of predominantly treating D. gallinae with insecticides is resistance (Abbas, 2014;Pavlićević et al., 2016). So far there has not been a regular monitoring of resistance in D. gallinae control. In that aspect, acaricide application in D. gallinae control has so far not been rational. In the application of SiO2 formulations, adaptations in D. gallinae behavior have been recorded -they moved to places which are not accessible for application.
Unlike acaricides, it is believed that the development of chemoresistance to Pulcap formulation is not possible, and due to a better distribution neither is the development of other adaptive mechanisms which have been recorded in SiO2 formulations (Fig 6). Effi cacy of Pulcap formulation and technology will not weaken over time.

Disadvantages
Pulcap formulation does not have prolonged eff ect on absorbent surfaces, such as a concrete fl oor. Th is fl aw requires repeated application, so that the subsequently exposed mites can also be aff ected. Application of Pulcap water emulsion can cause intermittent movement of conveyor and manure belts, which can be fi xed by applying adsorptive powder (Fig 7). Cages and equipment get dirty to a somewhat greater extent, but hygienic conditions can be maintained.

Long-term control plan: the program
In addition to the application technology, we have also designed a complete program based on Pulcap formulation and control technology. Th e program provides a comprehensive approach and maximizes the principles of preventive medicine and rational control through the short-term goal of highly ef-fi cient and safe suppression and the long-term goal of D. gallinae eradication and introduction of biosecurity measures (Pavlićević et al., 2018b). Another important element of the program is the environment and simplifi cation of its conditions (Pavlićević et al., 2019). Th e program will produce its full effect only when it is implemented systematically, on a wider area, horizontally and vertically (parent fl ocks, rearing, production), which requires institutional support. For new and non-infested farms and poultry houses, the program is based on biosecurity -prevention of mite introduction.

Cost-eff ectiveness
Th e cost of a product and technology can be correctly estimated only through i ts cost-eff ectiveness ratio. A proposed estimation of products and methods for D. gallinae control is the annual expenditure (during the regular fl ock production period). Th e control program, which enables eradication from the production facilities and introduction of biosecurity measures, is the most cost-eff ective type of D. gallinae control, which eliminates any further expenditures for the farmer.

Other
Adequate prerequisites for the rational control are detection and monitoring are necessary because they provide a relevant insight into the presence of D. gallinae infestation, its intensity and extensity (Pavlićević et al., 2007(Pavlićević et al., , 2018b.
Th e rational control must be up-to-date. Th erefore, it is conditioned by regular periodic comparative assessments of formulations and methods for control, as well as providing timely information for experts and farmers.

CONCLUSIONS
Having analyzed the 11 criteria of rational control and compared it to the most important current solutions, we found that Pulcap formulation and technology is an example of rational control of D. gallinae. Th e use of non-toxic substances in prevention, with proven high effi cacy creates the necessary basis for the fundamental improvement of D. gallinae control. Th ere are disadvantages, which are important to be minimized with further development and, as much as possible, to be avoided or totally eliminated in the end.