Viruses are the most abundant biological entities on Earth and can be found in a variety of environments. A high prevalence of viruses in marine and freshwater systems was initially reported by Spencer in 1955, but the ecological significance of viruses is insufficiently known even until the present day. Viruses are known to play a key role in the biology of freshwater bacteria: controlling the bacterial abundance, composition of species, and acting as intermediaries in the transfer of genes between bacterial populations. In our study a variety of viromes of the IleBalkhash water basin were identified. It was found that the composition of viruses of the Ile-Balkhash region is made up not only of a wide variety of autochthonous viruses typical for phytoplankton hydro ecosystems, but also of representatives of allochthonous viruses-such families as Coronaviridae, Reoviridae and Herpesviridae-indicating anthropogenic pollution of the basin. The research designed to investigate the viral abundance, spread, infectious cycle, seasonal dynamics, composition of the viral community, and the influence of viruses on the bacteria, phytoplankton and recycling of nutrients, as well as the impact of environmental factors on the viral ecology in a variety of marine and freshwater systems is very relevant nowadays.

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In recent years, there have been a number of reports on the successful use of immunostimulatory complexes with saponins and viral glycoproteins as veterinary vaccines and in clinical trials for human medicine. The saponins Algiox, Sapanox and Pangisan were isolated and purified by HPLC from Allochrusa gypsophiloides, Saponaria officinalis and Gypsophila paniculata plants in Kazakhstan and they proved to have low toxicity in experiments with mice, chickens and chicken embryos. Algiox, Sapanox and Pangisan can be used to create immunostimulatory complexes (ISCOMs) similar to saponin-Quil-A-containing ISCOMs both in structure and in immunostimulatory efficiency. The adjuvant effect of the obtained saponins was studied by subcutaneous injection of mice with ISCOMs containing these herbal saponins and lipids and glycoproteins of H7N1 influenza virus. Sapanox, Pangisan and Algiox from Kazakhstani plants of the family Caryophyllaceae could be considered an additional source of highly effective adjuvants not only for veterinary vaccines but also for human medicine.

Pathogenic E. coli cause urinary tract, soft tissue and central nervous system infections, sepsis, etc. Lytic bacteriophages can be used to combat such infections. We investigated six lytic E. coli bacteriophages isolated from wastewater. Transmission electron microscopy and whole genome sequencing showed that the isolated bacteriophages are tailed phages of the Caudoviricetes class. One-step growth curves revealed that their latent period of reproduction is 20–30 min, and the average value of the burst size is 117–155. During co-cultivation with various E. coli strains, the phages completely suppressed bacterial host culture growth within the first 4 h at MOIs 10−7 to 10−3. The host range lysed by each bacteriophage varied from six to two bacterial strains out of nine used in the study. The cocktail formed from the isolated bacteriophages possessed the ability to completely suppress the growth of all the E. coli strains used in the study within 6 h and maintain its lytic activity for 8 months of storage. All the isolated bacteriophages may be useful in fighting pathogenic E. coli strains and in the development of phage cocktails with a long storage period and high efficiency in the treatment of bacterial infections.

Newcastle disease virus (NDV) is an important pathogen in poultry. Waterfowl and a number of other avian species serve as the host for NDV. Severity of the disease is variable and infected animals mainly develop respiratory and neurological symptoms. Outbreaks of NDV in poultry are recorded regularly in the Republic of Kazakhstan despite the widespread use of vaccines. Here we present evidence that nucleic acid found in open water bodies in Kazakhstan can be detected by means of next-generation sequencing and belongs to at least three distinct genotypes of NDV.