Clinical symptoms and signs in hamsters during experimental infection with the SARS-CoV-2 virus (Coronaviridae: <i>Betacoronavirus</i>)

Introduction. At the beginning of December 2019, humanity has faced a new problem caused by coronavirus. In Hubei province of central China, epidemic events associated with severe primary viral pneumonia in humans began to develop. The isolated etiological agent was identified as a representative of Coronaviridae family. The global pandemic associated with the new coronavirus infection, acute respiratory syndrome type 2 (Severe acute respiratory syndrome 2, SARS-CoV-2), has become a challenge for humanity. Objective. In our work, we assessed the replicative ability and pathogenesis of the SARS-CoV-2 virus in hamsters. Materials and methods. Syrian hamsters (n=16) randomly divided into two groups were used in experiment. The first group was infected intranasally with the SARS-CoV-2 virus, strain SARS-CoV-2/human/KAZ/KZ_Almaty/2020 deposited in GenBank under number MZ379258.1. The second group remained as a control group. Clinical manifestations of the disease in hamsters were observed within 14 days. Samples were collected on days 3, 5, 7, 9, 12, and 14 postinfection. The obtained samples were tested for viral isolation in cell culture, histological examination and analysis of viral RNA by RT-PCR. Results. SARS-CoV-2 virus isolates showed efficient replication in the lungs of hamsters, causing pathological lung lesions in animals infected intranasally. Clinical manifestations of the disease in hamsters infected with this virus were characterized by a decrease in temperature and body weight, wetness and ruffled fur, and frequent stroking of the nasal planum. High virus titers were observed following the virus isolation in cell cultures from nasal, oral swabs and lungs of animals infected intranasally. Pathological autopsy demonstrated pathological changes in the lungs. Moreover, transmission by airborne droplets has been established when a healthy hamster was kept together with animals infected using the intranasal method. Conclusion. In conclusion, our study showed that the Syrian hamster model is a useful tool for studying the SARS-CoV-2 pathogenesis, as well as testing vaccine candidates against acute respiratory syndrome type 2

Duration of immunity against infectious rhinotracheitis and bovine viral diarrhea after vaccination in calves in southern region of Kazakhstan

Some of the most economically significant viral infections affecting cattle globally include infectious bovine rhinotracheitis (IBR) and bovine viral diarrhea (BVD). Both viruses cause a wide range of clinical consequences and significant economic losses. Recent serological surveillance in Kazakhstan showed that these infections persist despite commercial vaccines, underscoring the need for more effective, locally appropriate immunization protocols. This study aimed to evaluate the duration of immunity conferred by a developed associated inactivated emulsion vaccine against IBR (strain “R-93”) and BVD (strain “Oregon C24V”), produced by the Research Institute for Biological Safety Problems. In the southern region of Kazakhstan. Of the 12 seronegative for BoHV-1 and BVDV clinically healthy crossbred calves (Friesian-Holstein and Kazakh Whiteheaded) eight were vaccinated, revaccinated, and monitored over a 9-month period for evaluation of the vaccine. Humoral immune responses were assessed using enzyme-linked immunosorbent assay and virus neutralization assays. Specific antibodies to BoHV-1 and BVDV were detected as early as day 7 post-vaccination, with titers peaking at 6.16 log2 and 6.24 log2, respectively, by day 28, and remaining above protective levels for at least 6 months. At 9 months, a challenge was conducted using virulent strains: no clinical signs or lesions in vaccinated animals, fever and respiratory systems in unvaccinated animals. These findings suggest that the tested inactivated vaccine is safe, immunogenic, and capable of providing sustained protection in crossbred cattle under local climatic conditions. Although the sample size was limited, the results allow us to make preliminary conclusions about the vaccine’s efficacy; however, further large-scale studies are needed

Development of an Inactivated Camelpox Vaccine from Attenuated Camelpox Virus Strain: Safety and Protection in Camels

This article describes the preparation of an inactivated vaccine from an attenuated strain of camelpox. The attenuated camelpox virus (CMLV) was grown in lamb kidney cells and in Vero cells. CMLV was accumulated to a significantly higher (p ≤ 0.05) titer in lamb kidney cells (7.75 ± 0.08 log TCID50/mL) than in Vero cells (4.00 ± 0.14 log TCID50/mL). During virus inactivation, a concentration of 0.05% beta-propiolactone (BPL) completely inactivated the virus in 6 h at a temperature of 22 ± 1 °C, while a concentration of 0.2% formaldehyde inactivated the virus in 8 h. However, a viral antigen inactivated by BPL was used for vaccine preparation. The inactivated viral antigen was adsorbed with aluminum hydroxide gel, and as a result, an inactivated candidate vaccine was prepared. While the safety of the candidate vaccine was tested in camels and white mice, the protective efficacy of the vaccine was tested only in camels. In the safety evaluation of the inactivated vaccine, the vaccine was not observed to cause any adverse effects in mice and camels. During the immunogenicity study in camels, antibody formation started (0.2 ± 0.16 log2) at Day 21 post-vaccination (PV), and the antibody titer peaked (1.33 ± 0.21 log2) at Day 60 PV and decreased at Day 90 PV (0.50 ± 0.22 log2). Furthermore, no antibodies were detected in vaccinated camels from Days 180 to 365 PV. Camels that received vaccination and were subsequently exposed to wild-type virus evinced a healthy state despite lacking antibodies. In contrast, unvaccinated camels exhibited susceptibility to camelpox upon challenge

Susceptibility and Transmission Dynamics of Peste des Petits Ruminants Virus in Domestic and Wild Ruminants: Experimental Insights from Kazakhstan

Peste des petits ruminants (PPR) is an extremely contagious viral disease that significantly affects the health of small ruminants and the economies of livestock, particularly in areas adjacent to endemic regions. This study focused on assessing the vulnerability of different domestic and wild animal species in Kazakhstan, which includes local sheep and goats, African Cameroon goats, saigas, calves, and ground squirrels, to infection by the PPR virus (PPRV). Experimental infections used a virulent strain of PPRV (Nigeria 76/1), with animals being monitored over a period of 21&ndash;28 days to evaluate clinical signs, pathological lesions, and viral dissemination. The manifestation of disease differed across species, breed, and age. In Cameroon, goats and saigas displayed severe illness with a mortality rate of 100% and elevated virus levels in key organs, whereas local sheep and goats presented age-related subacute, abortive, and latent manifestations. Calves exhibited mild, subclinical infections, while ground squirrels showed no susceptibility. Viral shedding was observed in the secretions of infected animals, with transmission occurring through airborne and alimentary pathways. No virus carriage was detected in the animals that had recovered. The investigation emphasizes the notable variations in PPRV pathogenesis and transmission risk among different species, highlighting the necessity for focused surveillance and control strategies to avert incursions in PPR-free areas like Kazakhstan

Safety and Immunogenicity of the Live Attenuated Vaccine QazCOVID-Live Against Coronavirus Infection COVID-19: Pre-Clinical Study Results

The research conducted in this preclinical study assesses QazCovid-live, a live attenuated COVID-19 vaccine created in Kazakhstan, by conducting preclinical evaluations of safety, immunogenicity, and allergenicity in various animal models, including mice, rats, hamsters, and guinea pigs. The vaccine, developed by attenuating SARS-CoV-2 via numerous Vero cell passages, had no significant adverse effects in acute and subacute toxicity assessments, even at elevated dosages. Allergenicity testing indicated the absence of both immediate and delayed hypersensitivity reactions. Immunogenicity evaluations revealed strong virus-neutralizing antibody responses, especially following intranasal and intratracheal delivery. Studies on reversibility and transmission further validated the vaccine’s stability and non-pathogenicity. The data indicate that QazCovid-live is safe, immunogenic, and prepared for clinical trials, presenting a potential strategy for COVID-19 prevention

Investigation of the Pathogenesis of Lumpy Skin Disease Virus in Indigenous Cattle in Kazakhstan

This study investigates the virulence properties and pathogenetic characteristics of the Kazakhstani strain of LSDV (LSDV KZ-Kostanay-2018) in indigenous cattle under controlled conditions. Twelve non-breed cattle were inoculated intradermally and monitored for clinical, pathological, and immunological responses. Clinical signs, including fever, skin nodules, and lymphadenopathy, emerged as early as day 5 post-infection (pi), with peak severity observed between days 11 and 14. Rapid seroconversion was observed, with 100% of animals showing virus-neutralizing antibodies by day 13. Pathological findings revealed extensive necrosis, thrombosis, and edema, with pronounced damage in the spleen, lungs, and lymph nodes. Histological analyses identified widespread destructive changes in the dermis and systemic tissues, consistent with highly aggressive disease progression. Viral genome and replication were confirmed in blood, skin nodules, and lymph nodes, with peak viral loads between days 11 and 14 pi. These results align with findings in Russian cattle infected with the Saratov/2017 strain but demonstrate more rapid symptom onset and severe pathology, suggesting strain-specific virulence. These findings contribute to a deeper understanding of LSDV pathogenesis and underscore the importance of regional adaptations in disease management

Duration of Protective Immunity in Sheep Vaccinated with a Combined Vaccine against Peste des Petits Ruminants and Sheep Pox

In this study, the ability of the combined vaccine against peste des petits ruminants (PPR) (Nigeria strain 75/1) and sheep pox (SPP) (NISKhI strain) to form a protective immune response for 12 months in Kazakh breed fine-fleeced sheep aged 6–12 months was demonstrated. The duration of the protective immunity of immunized sheep from PPR and from SPP was evaluated using a serum neutralization test (SNT), followed by testing of the resistance of vaccinated sheep to infection with the field strain Kentau-7 of the PPRV and the virulent strain A of the SPPV. The PPR antibody response was additionally measured by c-ELISA. A single immunization of sheep with a combined vaccine in a volume of 2.0 mL, containing the PPR and SPP vaccine viruses in the titers of 103.0 TCID50/mL, provided reliable protection of animals from two infections simultaneously for 12 months (observation period). At the same time, in sheep immunized with the combined vaccine, antibodies of PPRV persisted for up to 12 months, with slight fluctuations. The combined vaccine induced 100% clinical protection against the field strain of PPRV and the virulent strain of SPPV in immunized sheep for up to 12 months, while unvaccinated animals became ill with the manifestation of clinical signs specific to PPRV and SPPV.</jats:p

Duration of Protective Immunity in Sheep Vaccinated with a Combined Vaccine against Peste des Petits Ruminants and Sheep Pox

In this study, the ability of the combined vaccine against peste des petits ruminants (PPR) (Nigeria strain 75/1) and sheep pox (SPP) (NISKhI strain) to form a protective immune response for 12 months in Kazakh breed fine-fleeced sheep aged 6–12 months was demonstrated. The duration of the protective immunity of immunized sheep from PPR and from SPP was evaluated using a serum neutralization test (SNT), followed by testing of the resistance of vaccinated sheep to infection with the field strain Kentau-7 of the PPRV and the virulent strain A of the SPPV. The PPR antibody response was additionally measured by c-ELISA. A single immunization of sheep with a combined vaccine in a volume of 2.0 mL, containing the PPR and SPP vaccine viruses in the titers of 103.0 TCID50/mL, provided reliable protection of animals from two infections simultaneously for 12 months (observation period). At the same time, in sheep immunized with the combined vaccine, antibodies of PPRV persisted for up to 12 months, with slight fluctuations. The combined vaccine induced 100% clinical protection against the field strain of PPRV and the virulent strain of SPPV in immunized sheep for up to 12 months, while unvaccinated animals became ill with the manifestation of clinical signs specific to PPRV and SPPV

The combined effects of temperature and relative humidity parameters on the reproduction of Stomoxys species in a laboratory setting.

In this study, Stomoxys species (S. calcitrans, S. sitiens and S. indica) were examined to improve on the current technique for mass rearing using a method of combined incubation parameters. Moreover, the reproductive potential of immature forms at various stages of development was defined. Immature forms of stable flies were incubated according to species. There was no significant difference in the number of immature forms obtained among species incubated under the same conditions. Six incubation parameters were used in combination, at temperatures (T) of 32°C, 27°C and 22°C and relative humidity (RH) of 90% and 70% RH. The combined method resulted in a higher number of eggs hatching at 32°C and 90% humidity as well as an increase in the number of larva pupated and emergence of imago at 27°C and 70% humidity

Emergence of the First Lumpy Skin Disease Outbreak Among Livestock in the Republic of Kazakhstan in 2016.

Lumpy skin disease (LSD) is an emerging transboundary viral disease of cattle originating from the African continent. Here we describe the first LSD outbreak reported in the Republic of Kazakhstan, in July 2016. Initially, LSD was reported in a cattle farm located 49 km from Kazakh &amp;ndash;Russian border in, Atyrau Oblast in West Kazakhstan. Subsequently, the disease spread to neighbouring farms situated within the same district. Following a preliminary investigation, the local State Veterinary Service declared a strict quarantine according to the State Contingency Plan, along with immediate total stamping out and cattle movement restrictions. During the outbreak, the number of affected cattle within an epidemiological unit reached 459 cattle out of registered 3557 susceptible cattle with 12.90% morbidity and 0.96%, mortality. This manuscript presents the epidemiological situation, the diagnosis, the control measures including mass vaccination and the stamping out campaign.s</jats:p