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Home / Equine Research Bank / Front Vet Sci / Integrated molecular and serological survey of Rhodococcus e...
Frontiers in veterinary science2025; 12; 1650186; doi: 10.3389/fvets.2025.1650186

Integrated molecular and serological survey of Rhodococcus equi in horses from three regions of Kazakhstan.

Abstract: is a facultative intracellular pathogen causing bronchopneumonia in foals; data from Central Asia are limited. We conducted a cross-sectional serological and molecular survey in horses from three regions of Kazakhstan (Kyzylorda, Almaty, Akmola). Unassigned: Sera from 312 animals (272 adults, 40 foals) on 20 farms were tested by indirect ELISA. Selected clinical samples underwent culture, PCR, and 16S rRNA sequencing. Unassigned: Overall seroprevalence was 8.3% (26/312; 95% CI 5.8-11.9). Positivity among foals was 25.0% (10/40; 95% CI 14.2-40.2) versus 5.9% (16/272; 95% CI 3.7-9.3) in adults, with farm-level clusters observed in the Almaty region. was isolated from three foals; a representative sequence was deposited (GenBank OP448586). Unassigned: Phylogenetic analysis placed the Kazakhstani isolate within a clade of equine-associated strains reported from Europe and East Asia (>99.5% identity). We provide molecularly confirmed evidence of circulation in horses from three regions of Kazakhstan, with higher seropositivity in foals and focal farm-level clustering. Findings support the need for broader geographic sampling, test validation against reference sera, and incorporation of management/risk-factor data. Limitations include the regional scope, small number of foals, and absence of environmental or human sampling.
Copyright © 2025 Zanilabdin, Ilgekbayeva, Otarbayev, Nissanova, Mussayeva, Takai, Suzuki, Kakuda, Kurman, Kassymov and Valiyeva.
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Publication Date: 2025-10-21 PubMed ID: 41195079PubMed Central: PMC12584071DOI: 10.3389/fvets.2025.1650186Google Scholar: Lookup
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Summary

This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.

Integrated molecular and serological survey of Rhodococcus equi in horses from three regions of Kazakhstan identifies the presence and prevalence of this pathogen, particularly in foals, and emphasizes the need for further epidemiological studies in the region.

Background and Purpose of the Study

  • Rhodococcus equi is a facultative intracellular pathogen known to cause bronchopneumonia primarily in foals.
  • Data regarding the presence and prevalence of R. equi in Central Asia, specifically Kazakhstan, has been limited.
  • The study aimed to investigate the seroprevalence and molecular presence of R. equi in horses from three distinct regions of Kazakhstan: Kyzylorda, Almaty, and Akmola.

Methods Used in the Research

  • A cross-sectional survey was conducted involving serological and molecular assays.
  • A total of 312 horses were sampled, comprising 272 adult horses and 40 foals, from 20 different farms.
  • Serological testing was performed using indirect ELISA to detect antibodies against R. equi in sera.
  • Clinical samples that showed indications of infection underwent bacterial culture, polymerase chain reaction (PCR), and 16S rRNA gene sequencing for molecular identification of R. equi.

Key Findings

  • The overall seroprevalence of R. equi in the sampled horse population was 8.3%, with 26 of 312 animals testing positive.
  • Foals showed a higher seroprevalence rate of 25.0%, in contrast to adults at 5.9%, indicating increased susceptibility or exposure in younger animals.
  • There were notable clusters of positive cases at the farm level, especially in the Almaty region, suggesting localized transmission or environmental exposure.
  • R. equi was successfully isolated from three foals, and the representative strain’s 16S rRNA sequence was submitted to GenBank (accession number OP448586).
  • Phylogenetic analysis demonstrated that the Kazakhstan isolate belonged to a clade closely related (>99.5% identity) to equine-associated strains reported from Europe and East Asia, indicating genetic similarity across geographical regions.

Interpretation and Implications

  • The study provides molecularly confirmed evidence that R. equi circulates among horses in Kazakhstan.
  • Higher seropositivity in foals reinforces the importance of focused surveillance and preventive measures in younger horses.
  • The observed farm-level clustering points to potential localized infection sources or management practices influencing pathogen spread.
  • Findings highlight the need to expand geographic sampling beyond the studied regions to understand the broader epidemiology of R. equi in Central Asia.
  • Further validation of serological tests against reference sera is necessary to ensure diagnostic accuracy in the region.
  • Incorporating data on farm management practices and risk factors could elucidate modes of transmission and inform control strategies.

Limitations of the Study

  • The study was limited to three regions of Kazakhstan and therefore may not represent the entire country or Central Asia.
  • The small number of foals sampled restricts the robustness of prevalence estimates for that subgroup.
  • The study did not include environmental sampling (e.g., soil, dust) or human sampling, which could provide a more comprehensive picture of R. equi ecology and zoonotic potential.

Conclusion

  • This integrated serological and molecular survey establishes the presence of Rhodococcus equi in horses from multiple regions of Kazakhstan, particularly highlighting the risk to foals.
  • The results encourage expanded surveillance, improved diagnostic test validation, and incorporation of farm management factors in future research to better control and understand R. equi infections in the region.

Cite This Article

APA
Zanilabdin M, Ilgekbayeva G, Otarbayev B, Nissanova R, Mussayeva G, Takai S, Suzuki Y, Kakuda T, Kurman S, Kassymov Y, Valiyeva B. (2025). Integrated molecular and serological survey of Rhodococcus equi in horses from three regions of Kazakhstan. Front Vet Sci, 12, 1650186. https://doi.org/10.3389/fvets.2025.1650186

Publication

Frontiers in veterinary science
ISSN: 2297-1769
NlmUniqueID: 101666658
Country: Switzerland
Language: English
Volume: 12
Pages: 1650186
PII: 1650186

Researcher Affiliations

Zanilabdin, Makpal
  • Kazakh National Agrarian Research University, Faculty of Veterinary and Zooengineering, Almaty, Kazakhstan.
Ilgekbayeva, Gulnaz
  • Kazakh National Agrarian Research University, Faculty of Veterinary and Zooengineering, Almaty, Kazakhstan.
Otarbayev, Bauyrzhan
  • Kazakh National Agrarian Research University, Faculty of Veterinary and Zooengineering, Almaty, Kazakhstan.
Nissanova, Raikhan
  • Virology Laboratory, Kazakh Scientific Research Veterinary Institute, Almaty, Kazakhstan.
Mussayeva, Gulzhan
  • National Veterinary Reference Center, Almaty, Kazakhstan.
Takai, Shinji
  • School of Veterinary Medicine, Kitasato University, Towada, Japan.
Suzuki, Yasunori
  • Tokyo University of Agriculture and Technology, Fuchu, Japan.
Kakuda, Tsutomu
  • School of Veterinary Medicine, Kitasato University, Towada, Japan.
Kurman, Serikzhan
  • Kazakh National Agrarian Research University, Faculty of Veterinary and Zooengineering, Almaty, Kazakhstan.
Kassymov, Yerken
  • Kazakh National Agrarian Research University, Faculty of Veterinary and Zooengineering, Almaty, Kazakhstan.
Valiyeva, Bayan
  • Kazakh National Agrarian Research University, Faculty of Veterinary and Zooengineering, Almaty, Kazakhstan.

Conflict of Interest Statement

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

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