RU2663629C1 - Cap for collecting larvae and small nematodes from human and animal feces - Google Patents

Abstract

FIELD: medicine; veterinary.SUBSTANCE: invention relates to medical and veterinary helminthology, namely to use of a cap for collecting larvae and small nematodes from human and animal feces. Cap is made in form of a polymeric cylindrical bowl, on the outer surface of which there are vertical furrows, on the inner surface equipped with a single-threaded thread.EFFECT: decrease in waste and increase in number of collected larvae and small nematodes.1 cl, 5 dwg, 2 tbl

Description

The invention relates to medical and veterinary helminthology, namely to laboratory cultivation of parasitic nematodes.

A device for collecting larvae and small nematodes from feces (A.S. No. 1391625) is known. The device comprises a bowl 1 with a recessed lateral surface in the form of an impeller 2. There are grooves 3 on the surface of the impeller and the bowl; semicircular cutouts 4 are on the outside of the bottom between the wings 4. The bowl 1 has the form of a hemisphere with a smooth inner surface. The device is immersed in feces, water is poured into the bowl 1. Nematodes, migrating, stumble on wings and rise along furrows 3 into bowl 1 with water, where they remain.

The disadvantages of this device are:

1) the limited working space (bowl volume = 1.5 ml) leads to shorter survival times for larvae and small nematodes (because bacteria that cover the surface of the body of nematodes and their metabolic products quickly cause water pollution and intoxication of nematodes, especially larvae 1st and 2nd stages of development), which means culling a significant part of the obtained material;

2) translucency, since it practically does not create contrast with translucent larvae and small nematodes, which makes it impossible to visualize the latter during the study without involving additional technical means;

3) structural complexity - the presence of wings is not functionally determined to the extent that justifies the consumption of material used for casting (with a bowl diameter = 1.7 cm base diameter = 3.5 cm): larvae and small nematodes possess hydrotaxis - the property of movement in the direction of greater humidity, so they crawl into the bowl, regardless of the presence of wings;

4) the presence of cuts from the bottom, designed to increase the area of the working surface, and, consequently, the number of larvae and small nematodes obtained, in reality only lengthens the period of their migration into the bowl, and, therefore, the period of their receipt.

The technical result consists in the fact that the use of the cap (GOST 32626-2014. "Polymer closures. General technical conditions", page 4) allows to reduce waste and increase the number of collected larvae and small nematodes, to reliably visualize their appearance in the cap container and save funds for its acquisition.

The technical result is achieved by the fact that the use of the cap allows you to collect larvae and small nematodes from the feces of animals and humans.

The invention is illustrated by drawings, where in FIG. 1 shows a device for collecting larvae and small nematodes from feces (AS No. 1391625): on the left is a plan view, on the right is a section A-A;

in FIG. 2 shows a cap consisting of a cylindrical body 1, inside of which there is a right single-thread 2 (continuous or intermittent depending on the manufacturer of this element). The outer surface of the cylindrical body 2 is provided with vertical grooves 3;

in FIG. Figure 3 shows a cap immersed in feces located in a Petri dish (in the center of the cap is an accumulation of collected larvae and small nematodes);

in FIG. 4 - the same, but increased;

in FIG. 5 is a micrograph of larvae and small nematodes collected from feces with a cap.

A cap for collecting larvae and small nematodes from feces is used as follows. In the Petri dish set the cap with the hole up. The feces under investigation are placed around it so that they fit snugly against the lateral surfaces of the housing 1 from all sides and along its entire height. The inner capacity of the cap is filled with water to the very top. Close the Petri dish. Helminths, actively moving in feces, in search of a cleaner environment, rise along the furrows 3 and fall into the capacity of the cap, to the bottom of which they soon settle. The cap is exposed for a predetermined time in a thermostat. The removed cap is used as a container for temporary storage of the studied helminths, which are removed with a pipette as necessary and microscopic.

To prove the feasibility of using the cap, experimental studies were conducted. In June-August 2017, feces were rectally obtained from Romanov breed sheep from 2 to 7 years old in a private peasant farm of the Vyborg district of the Leningrad Region (60.735175 ° N, 29.004207 ° E). In the laboratory on the basis of the Department of Parasitology. V.L. Yakimova FSBEI HE “St. Petersburg State Academy of Veterinary Medicine” conducted a preliminary coprooscopic study using the modified S. Darling method, which showed the presence of nematode eggs in the studied feces. Then, larvae from eggs were cultured according to the method of A.M. Petrova and V.G. Gagarin, for which a 10-gram sample of feces was placed in Petri dishes (2 series of 45 pieces), the cups were closed and placed in a cultivation thermostat for 10 days at a temperature of 27 ° C. Daily Petri dishes were removed from the thermostat to ventilate and moisten the feces. After completion of the cultivation period (when the larvae of the nematodes managed to leave the eggs and undergo two molts, reaching the invasive stage of development optimal for the study), feces in the first series Petri dishes were equipped with devices for collecting larvae and small nematodes from feces (A.S. 1391625), and in the Petri dishes of the second series - caps. The cups of the devices and the capacity of the caps to the brim were filled with clean water and left to expose. After 24 hours, the collected larvae from each sample (Figs. 3 and 4) were individually selected with a pipette, and the devices and cap containers were again filled with water and continued exposure. The viability of the larvae was determined by their mobility and the preservation of morphological structures under a Mikmed-6 microscope at a 40-fold increase (Fig. 5). Then they were fixed with 70 ° C alcohol and the number of larvae was counted. The total exposure time was 72 hours. Upon completion of exposure, the obtained larvae were examined for viability, and after that they were fixed with alcohol and their number was calculated. The research results are presented in table 1.

The cap can be used to collect larvae and small nematodes from feces in order to: 1) qualitative and quantitative diagnosis of nematodes of humans and animals; 2) determination of anthelmintic resistance in parasitic nematodes and screening of drugs against them in vitro; 3) obtaining samples of nematode antigens for the manufacture of serological diagnostics and vaccines; 4) the study of the biology of nematodes and the development on its basis of more advanced control measures; 5) DNA sequencing of nematodes in the interests of evolutionary biology (since the detection of similar helminths in animals of different species (currently existing or extinct) may indicate phylogenetic kinship or general habitat). In addition, the design of the cap is much simpler than the design of the known device, which saves money on the purchase of the cap (table. 2).

* Production of 5 products by molding plastic into a pre-created silicone mold, provided that the original product is provided as a master model to NK-Technology employees (http://nktech3d.ru); according to data as of June 20, 2017;

** The price multiplied by 5, indicated on the website of the Kit-Hobby online hypermarket (https://kit-hobby.ru/catalog/tovary_dlya_ofisa/bakaleya/16179/) for non-carbonated drinking water “Holy Spring”, 0.5 L, in a plastic bottle; according to data on 20.06. 2017.

Thus, the use of a cap to collect larvae and small nematodes from animal and human feces is a simple and economical alternative to using the device, since the cap has all the necessary performance characteristics (the presence of a water tank, vertical furrows, a height that allows it to be placed in a Petri dish), and the money savings even with the purchase of the cap along with the corking container are estimated as 30 times and the time savings as 7 times.

Claims (1)

The use of a cap made in the form of a cylindrical polymer bowl, on the outer surface of which vertical grooves are located, and on the inner surface equipped with single-thread, to collect larvae and small nematodes from human and animal feces.

Images