RU198246U1 - A device for the experimental selection of disinfectants for disinfecting soil contaminated with helminth eggs or protozoa cysts and oocysts - Google Patents

Abstract

The utility model relates to technical devices for medical and veterinary parasitology intended for the experimental selection of the most effective disinfectants from a large number of known or new disinfectants for disinfecting soil contaminated with helminth eggs, cysts and oocysts of protozoa. The device consists of a closed container made of stainless corrosion-resistant austenitic ferritic steel, has the shape of a rectangular parallelepiped, size 1500 × 1500 × 700 mm, the bottom of the tank is made in the form of a funnel with an inclination angle of 5% relative to the normal to the base. At the corners of the casing, supports with a lower extension are provided to give stability to the structure, on the upper part of the casing there are two metal covers 1000 × 700 mm in size. In the central part of the covers there is a foam drain and an overflow valve for adjusting the internal pressure, mounting holes for installing nozzles of the irrigation system are provided around the perimeter, a vertically opening metal door of size 650 × 1450 mm with reinforced hinges and two handles on the sides is provided for one of the model’s walls convenience of unloading the soil and thorough cleaning of the column from the inside. A temperature and humidity control unit is installed on the opposite side of the container body. Samplers are installed at various depths of the container (soil). A gauze test swab impregnated with a suspension of helminth eggs or a suspension of cysts and oocysts of protozoa is placed inside the sampler. The presence or absence of viable bioobjects in the samplers after testing the means in the device, as well as the presence of residual disinfectant activity in the spent solution, serves as an indicator of the effectiveness of the disinfectant. active substance.

Description

The utility model relates to technical devices for medicine, veterinary medicine and parasitology, in particular to models of soil ecosystems contaminated with helminth eggs, protozoa cysts and oocysts, and is intended for experimental selection of the most effective disinfectants from known and new disinfectants for soil disinfection from parasitic pathogens diseases.

To date, about 70 species of helminths and a large number of pathogenic protozoa are found in Russia. Helminthozoonoses are actively distributed - diseases common to humans and farm animals. In cattle, some helminths sharply reduce weight gain, milk production, worsen the quality of the wool of sheep and goats, and reduce the fecundity of birds. Many helminths cause massive deaths of domestic animals, especially young animals. Improper disposal of livestock waste, as well as dead animals, leads to infection of water and soil with parasitic diseases. As a result, every year when consuming berries, fruits, vegetables, herbs, fish and meat, millions of people become infected with such invasions as ascariasis, trichocephalosis, toxocariasis, and strongyloidosis.

In this regard, the experimental selection of disinfectants and the development of drugs that are effective in combating parasitic pathogens are of particular importance. Most chemical disinfectants that are active against bacteria and viruses do not have an effective effect on helminth eggs, protozoa cysts and oocysts, whose shells have a complex structure, which makes it difficult for chemical compounds to penetrate. A specific disinfectant must first penetrate the lipid layer of the outer shell of the oocyst, and then overcome the glycoproteins of its inner shell before it can damage the cysts, oocystamprostheses and helminth eggs containing membranes.

Until now, disinfectants of a chemical nature with ovocidal properties continue to be the main means of disinvasion of helminth eggs, cysts and oocysts of protozoan soils.

Existing methods for disinvasing surfaces, various objects contaminated with helminth eggs, protozoa cysts and oocysts, are based on the use of such chemicals as halogens or their derivatives (bleach, calcium hypochlorite, DP-2, etc.), oxidizing agents (perhydrol, potassium perfluoride etc.), aldehydes (formaldehyde, glutaraldehyde, etc.), etc.

It should be noted that despite the effectiveness of chemicals in the treatment of various surfaces in the premises of medical institutions and household facilities contaminated with helminth eggs, cysts and oocysts of protozoa, their scaled use for decontamination of soil from helminth eggs, cysts and protozoa oocysts without prior experimental selection of effective disinfectants, without the development of soil disinfestation regimes, without the development of appropriate technology for large-scale soil disinfection (soil, sand, humus) at different depths is an ineffective, expensive and very dangerous disinfection operation for the ecology of the environment, human and animal health.

Only for one trial experiment with disinfectant disinfection of soil contaminated with helminth eggs, protozoa cysts and oocysts, tones of a disinfectant working solution will be required. In this case, the effect may turn out to be zero, and the environmental consequences are catastrophic.

In this regard, the experimental selection of effective disinfectants for the disinfestation of soil contaminated with helminth eggs, cysts and oocysts of protozoa, the development of disinfection modes for any type of soil with different structural and physico-chemical characteristics to different depths under different climatic conditions, the development of technology for soil disinvasion and pressing issues of modern parasitology, disinfection, medicine and veterinary medicine.

1. To test disinfectants and develop technologies designed to disinfect soil contaminated with helminth eggs, protozoa cysts and oocysts, test surfaces (wood, cement) or glass laboratory glassware (Petri dishes or boxes), in which a suspension of helminth eggs or 0.5 g of feces seeded with helminth eggs is placed, then the samples are poured with an aqueous solution of the tested disinfectant, they stand a certain amount of time for inactivation of bioagents (from 30 minutes to 24 hours). After the expiration of the exposure by conventional methods, the number of live helminth eggs or cysts and protozoa oocysts in the samples is determined. Guidelines MUK 4.2.2661-10. Methods of sanitary-parasitological studies. - S. 57-59.

However, the main disadvantage of the analogue is that the positive test results of disinfectants on test surfaces and in laboratory glassware are not reproducible when disinfecting the soil in the environment. For laboratory disinfection of soil, it is impossible to reproduce the structure, density, physical, biological and chemical properties and characteristics of multilayer soil of various ecosystems.

The prototype of the proposed device for the safe experimental selection of disinfectants for disinfecting soil samples infected with helminth eggs, protozoan cysts and oocysts is a wooden box 20 cm wide, 45 cm long and 20-30 cm deep, the bottom and walls have openings, and inside are separated by a shield into three sections, each 15 cm long. The sections are intended for testing the product at 24 exposures; 48 and 72 hours, respectively. For control use separate boxes. Prepared soil is placed in boxes in layers and at the same time egg samples are laid in the intended layers on strips of filter paper to a depth of 15; 10 and 5 cm or on frames (staples) of soft metal wiring, covered with a plastic cover. Then the soil in boxes from a watering can or hydraulic console is watered with a disinfectant. After a certain exposure, soil samples are taken from each target level and helminth eggs are isolated to determine their viability. Simonov A.P. Methods of testing and selection of ovocidal chemical compounds for soil disinfection. - Bulletin of the All-Union Order of the Red Banner of Labor Institute of Helminthology. K.I. Scriabin, 1977, no. 19. - S. 60-66.

The main disadvantages of the prototype are:

- open boxes with soil contaminated with helminth eggs, drilled walls and the bottom of the boxes according to environmental and biological safety requirements cannot be used to test chemicals of different hazard classes and helminth eggs related to pathogens of groups 3-4 pathogenicity groups;

- failure to comply with the requirements of general safety and biological safety when performing work on testing hydrogen peroxide and peroxide disinfectant compositions due to abundant pricing in the interaction of peroxide composite disinfectants with soil in the boxes, which leads to the release of infected soil into the environment through openings and slots of the boxes;

- does not provide uniform wetting of all soil layers with a disinfectant and its uniform decontamination due to the small cross-sectional area of the boxes, in which the solutions of the tested disinfectants easily flow down the walls and flow out through the holes in their walls;

- it is difficult, inconvenient, and unsafe to look for and remove strips of filter paper or other objects with helminth eggs from highly moistened soil (dirt) for transfer to a parasitological laboratory to determine the level of egg inactivation after exposure to soil;

- does not allow for safe testing of soil from crates to kraft bags after testing, which are to be sent for incineration, etc.

The technical result of the proposed utility model is to ensure the biological and technical safety of works on the experimental selection and testing of disinfectants necessary for the disinfestation of soil contaminated with helminth eggs or protozoa cysts and oocysts, ensuring the reliability of the results of disinfecting the soil at various depths, facilitating and simplifying operations for placement in the soil and excavation of samples of biomaterial from it.

Figure 1 shows a device for the experimental selection of disinfectants for disinvasion of soil contaminated with helminth eggs or protozoa cysts and oocysts.

The model of the soil ecosystem is a container body (7) made of stainless corrosion-resistant austenite-ferritic steel, has the shape of a rectangular parallelepiped with a base size of 1500 × 1500 mm and a height of 700 mm. For the best flow of the experimental liquid into the receiving tank, the tank bottom is made in the form of a funnel with an inclination angle of 5% relative to the normal to the base, there is a hole with a diameter of 50 mm in the center of the tank bottom, a metal mesh with a mesh size of 2 × 2 mm is installed on the bottom of the bottom, outside the bottom a threaded connecting fitting is installed to connect the metal cylinder of the receiving sampler. To ensure an acceptable working height, as well as the possibility of installing communications, at the corners of the housing, supports (9) with a lower extension (10) are provided to give stability to the structure.

On the upper part of the model are two metal covers (1), the overall dimensions of which are 1000 × 700 mm. They are necessary for loading the soil, have a swing structure relative to the transverse axis of the housing (7), equipped with loops (2) and handles (5). In the central part of the covers (1) there is a foam deflector (11) and a bypass valve (12), respectively, with the help of which it is possible to adjust the internal pressure that increases during oxidative reactions in the soil and to discharge the necessary amount of foam during the experiment. The cross member in the body structure, located between the upper metal covers (1) and serving as a stop, is equipped with technological slots (18) with a width of 10 mm and a final diameter d = 10 mm for mounting the samplers (Fig. 2) in fixed positions.

Along the perimeter, mounting holes (13) are provided for installing nozzles of the irrigation system, which allows safe uniform treatment with a fixed amount of disinfectant, as well as cleaning and washing the inside of the model after work.

On one of the walls of the model, a vertically open metal door (4) of size 650 × 1450 mm with reinforced hinge hinges (6) and two handles (5) on the sides is provided for easy unloading of the soil and full cleaning of the column from the inside. A mounting box (14) is provided on the opposite side of the housing (7), which allows the optional installation of a temperature and humidity control unit. There are also mounting holes (15) for humidity and temperature sensors.

In the central part of the inclined bottom (8) there is a drain neck (17) with a thread and a filter screen for collecting disinfectant samples during the experiment into a sampler (16), which is a cylinder of a fixed volume.

The materials of the model parts are selected taking into account possible critical stresses on the component parts, the effects of disinfectants, difficult weather conditions. The requirements of tightness, as well as the requirements of environmental and biological safety in the course of the experiments were taken into account.

Three to fifteen samplers with helminth eggs or protozoa cysts and oocysts are placed inside the model’s case.

The sampler (Fig. 2) is designed for unimpeded extraction from soil massif at different stages of the experimental selection of bioassay disinfectants containing helminth eggs or cysts and protozoa oocysts. It consists of two hemispheres with a radius of R-50 mm, made of stainless steel mesh with a mesh size of 5 mm, interconnected.

For convenience, the location of the sampler inside the soil, the upper part of the sphere is rigidly connected to a vertical metal guide of various lengths L and diameter d = 10 mm. At the end of the guide, a ring with a diameter of D = 42 mm is welded, which serves as a grip for the convenience of extracting the sampler, as well as a marker to identify the location and depth of laying the bioassay into the ground. A gauze test swab containing helminth eggs or cysts and protozoan oocysts, at a concentration of 2 × 10 ^2-3 units / 1 ml, is placed inside the scope of the sampler. The impact of the test solution of the test disinfectant on the test swab with a bio-object occurs by the disinfectant solution entering the sampler through the mesh cells. Samplers with biomaterial are immersed in the soil to the appropriate depth (50; 100; 150; 300 and 500 mm). If necessary, the number of samplers can be increased by 2 and 3 times.

Example 1. To test the capabilities of the proposed device in the laboratory experimental selection of the most effective disinfectants for sand disinfestation from playgrounds, a working solution of the new GLAVHLOR EXTRA disinfectant in a concentration of 0.3% active chlorine is used. For this, 1 m of sand is poured into the working capacity of the device to the mark of the device’s capacity of 500 mm. In the sand to a depth of 50; one hundred; 150; 300 and 500 mm install samplers with biomaterial. One gauze test swab with pork ascaris eggs (Ascarissuum) is placed in the scope of each sampler. A sealed threaded receiving cylinder (chemical sampler) is attached to the bottom of the column to collect the spent disinfectant solution.

After loading the capacity of the device for soil disinvasion, they begin to perform work on disinvasing the soil with a disinfectant.

Using a hydraulic console, sand is poured with a 0.3% solution of GLAVCHLOR EXTRA (active chlorine) in a ratio of 1: 1 (disinfectant solution volume / soil volume) and left for 48 hours at an ambient temperature of 16 ° C. After the expiration of the exposure time of the disinfectant to the soil, all samplers are removed from the device body and transferred to a parasitological laboratory to estimate the number of viable Ascarissuum eggs in each experimental sample. Each test swab is removed from the sampler and suspended in a solution of a universal catalyst to remove disinfectant residues, then after centrifugation, the precipitate is suspended in physiological saline. The viability of the eggs after treatment with the tool is determined by cultivation. Monitoring the development of eggs is carried out twice a week, while paying attention to the crushing of eggs and the formation of larvae. With the beginning of the formation of larvae, the experimental samples were examined in an optical microscope on a thermostated table. The presence of motile larvae in the samples indicates the absence of disinvasion activity of the agent in this test variant.

A sampler for chemical research is separated from the device body and transferred to a chemical laboratory, where the residual content of active chlorine in the spent solution of the disinfectant is determined. Then the door of the device is opened, and the case is released and cleaned of soil and disinfectant.

Parasitological studies have shown that in the test tampons with helminth eggs after disinfection of sand in a device with a 0.3% solution of GLAVHLOR EXTRA (active chlorine), a large number of motile larvae in pork roundworm eggs (more than 73% of eggs from initial egg concentration in the initial suspension). Chemical and analytical studies of the spent disinfectant solution showed the absence of active chlorine in the liquid collected after decontamination.

Thus, the obtained data of parasitological and chemical-analytical studies indicate that a 0.3% solution of GLAVCHLOR EXTRA loses its initial disinfecting and oxidizing activity upon contact with a large amount of soil, and disinfectant solutions at low concentrations of active chlorine do not effective for soil disinvasion.

Example 2. To test the proposed device in the laboratory experimental selection of the most effective disinfectants for sand disinfection, use a solution of disinfectant GLAVCHLOR EXTRA in a concentration of 3.0% active chlorine. For this, 1.1 m ^{3 of} sand is poured into the working capacity of the device to the mark of the device's capacity of 500 mm. In the sand to a depth of 50; one hundred; 150; 300 and 500 mm install samplers with biomaterial. Each sampler contains one gauze swab with pork ascaris eggs (Ascarissuum). A sealed receiving chemical sampler is attached to the bottom of the column.

Using nozzles of the device’s irrigation system, sand is irrigated with a 3% solution of GLAVCHLOR EXTRA (active chlorine) in a ratio of 1: 1 (disinfectant solution volume / soil volume) and left for 24 hours at an ambient temperature of 13 ° C. After the expiration of the exposure time to the soil with a disinfectant, samplers are taken out of the device body and transferred to a parasitological laboratory to estimate the number of viable Ascarissuum eggs in each experimental sample. Each test swab with biomaterial is removed from the sampler and suspended in a solution of a universal catalyst, then after centrifugation, the precipitate is suspended in physiological saline. The viability of helminth eggs is determined by cultivation. A sampler for chemical research is separated from the device body and transferred to a chemical laboratory, where the residual content of active chlorine in the spent solution of the disinfectant is determined.

Then the door of the device is opened, and the case is released and cleaned of soil and disinfectant.

It was found that in samples of biomaterial (test swab with helminth eggs) after disinfection of sand with a 3% solution of GLAVHLOR EXTRA (active chlorine), there are no viable pork roundworm eggs. Chemical-analytical studies showed the presence of an active substance (approximately 0.1% of active chlorine) in the liquid collected after decontamination.

Thus, the obtained data of parasitological and chemical-analytical studies indicate that a 3.0% solution of GLAVCHLOR EXTRA is effective in sand disinfestation.

Example 3. The proposed utility model is used to test the disinvasion activity of working solutions of the disinfectant GlavchlorFood. For this, 1 m ^{3 of} soil is poured into the working capacity of the device in the form of rotted manure (humus) to the mark of the device’s capacity of 500 mm. Into the soil to a depth of 100; 300 and 500 mm install samplers with biomaterial. One gauze test swab with the eggs of the pathogen Toxacaracanis is placed in the scope of each sampler. A sealed threaded receiving cylinder (chemical sampler) is attached to the bottom of the column to collect the spent disinfectant solution.

After loading the capacity of the device for soil disinvasion, they begin to perform work on disinvasing the soil with a disinfectant.

Using nozzles of the model’s irrigation system, sand is irrigated with a 4.0% solution of GlavchlorFood (active chlorine) in a 1: 1 ratio (disinfectant solution volume / soil volume) and left for 24 hours at an ambient temperature of 15 ° С. After the expiration of the exposure time to the soil with a disinfectant, samplers are removed from the device body and transferred to a parasitological laboratory to estimate the number of viable eggs in each experimental sample. For this, each test swab is removed from the sampler and suspended in a solution of a universal catalyst to remove residual disinfectant, then after centrifugation, the precipitate is suspended in physiological saline. The viability of the eggs after treatment with the tool is determined by cultivation. In samples of the spent disinfectant solution, the content of active chlorine is determined. Then the vertical door of the device is opened and the case is released and cleaned of soil and disinfectant.

The performed studies showed that on the test test tampons with helminth eggs after disinfection of the soil (humus) with a 4% solution of GlavchlorFood (active chlorine), there are no viable eggs of the toxacarose pathogen. Chemical and analytical studies of the spent disinfectant solution showed the presence of active chlorine at a concentration of 0.12% in the liquid collected after decontamination.

The obtained data of parasitological and chemical-analytical studies indicate that the 4.0% solution of GlavchlorFood for active chlorine is effective in the disinfestation of humus from eggs of toxacarosis pathogens. The proposed utility model is similarly used for the experimental selection of disinfectants and chemicals for the disinfestation of soil contaminated with cysts and oocysts of pathogenic protozoa

Thus, the obtained experimental results indicate that the proposed utility model provides modeling of the soil ecosystem contaminated with helminth eggs, protozoan cysts and oocysts, is an economical, safe and convenient device that simulates in laboratory conditions the structure, climatic conditions, physical, biological and chemical properties and characteristics of soil contaminated with eggs, cysts and oocysts of various pathogens of parasitic infections. The proposed device can also be successfully used for the detailed development of modes and technology for the disinfestation of various types of soil.

Claims (1)

The device for the experimental selection of disinfectants for disinfecting soil contaminated with helminth eggs or protozoa cysts and oocysts is a stainless steel corrosion-resistant austenitic-ferritic steel tank body, has the shape of a rectangular parallelepiped with a size of 1500 × 1500 × 700 mm, the bottom of the tank is made in the form of a funnel with an angle a slope of 5% relative to the normal of the base, there is a hole with a diameter of 50 mm in the center of the bottom of the tank, a metal mesh with a mesh size of 2 × 2 mm is installed on the bottom of the bottom, a connecting fitting with a thread is installed outside the bottom for connecting the metal cylinder - the receiving sampler for collecting disinfectant samples , at the corners of the casing, supports with a lower extension are provided to give stability to the structure, on the upper part of the casing are two metal covers 1000 × 700 mm in size, having an oar structure relative to the transverse axis of the casing, provided with hinges and handles in the central covers are equipped with a foam outlet and an overflow valve for adjusting the internal pressure, the cross member in the housing structure located between the upper metal covers and serving as an emphasis is equipped with technological slots 10 mm wide and a final diameter d = 10 mm for mounting from 3 samplers to 15 samplers with helminth eggs or by cysts and oocysts of protozoa in fixed positions, along the perimeter there are mounting holes for installing nozzles of the irrigation system, on one of the model walls there is a vertically open metal door of size 650 × 1450 mm with reinforced hinge hinges and two handles on the sides, on the opposite side of the container body a temperature and humidity control unit is installed, the device also contains samplers with helminth eggs or protozoa cysts and oocysts at a depth of 50, 100, 150, 300, and 500 mm, which are two hemispheres with a radius of R-50 mm, made of stainless steel mesh with p For example, 5 mm cells interconnected, in which a gauze swab impregnated with a suspension of helminth eggs or cysts, protozoan oocysts is placed, the upper part of the sphere is rigidly connected to a vertical metal guide, a ring with a diameter of 42 mm is welded to the end of the guide.

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