Experimental Study of the Role of Horsetail Equisetum Fluviatile L. In the Achira Outbreak of Gaffa Disease

Abstract

The purpose of research is to study the role of the marsh horsetail, or river horsetail, Equisetum fluvia-tile L. in the Achira outbreak Gaffa disease. The study was carried out in the period from 2021 to 2022 at the State Budgetary Educational Institution of Higher Education of the Northern Trans-Urals. Hydrobotani-cal sampling was carried out in water bodies, in the coastal zone, including in places where horsetail grows and on rafting vegetation. Samples were taken at 12 stations (6 stations each on lakes Ish-menevskoye and Andreevskoye), the location of sampling points for aquatic and coastal aquatic vegeta-tion was the same. To take into account the biomass and number of horsetail shoots, 10 rectangular plots of 2 × 5 m were laid out, the area of one was 10 m2. At each site, a sample of horsetail shoots was taken from the survey area, the number of shoots, their height and the wet weight of the cutting were deter-mined. On Lake Andreevskoye, Tobolsk District, the average specific number of horsetail shoots was 20 individuals/m2 with a specific biomass (wet weight) of 74.75 g/m2. On Lake Ishmenevskoye, Tobolsk District, the average specific number of horsetail shoots was 23 individuals/m2 with a specific biomass (wet weight) of 160.75 g/m2. When white mice were fed fish containing horsetail detritus, clinical signs similar to those of the Gaffa disease were noted: fearfulness, decreased motor activity, purulent one- or two-sided conjunctivitis, the “triangle” position and the “frog” position. The mortality rate in mice during the biological test was 60 %. In addition to clinical signs similar to the Gaffa disease, icterus of the skin of the ears, distal limbs, tail and the release of bright yellow urine were noted, which is not typical for the Gaffa disease. Considering the low biomass of horsetail in the disadvantaged lakes Andreevskoye and Ishmenevskoye and the presence of icterus in experimental animals, it can be argued that horsetail is not the main reason provoking the formation of toxin in the body of fish.