Camel herders in the Mangystau region reported a respiratory disease outbreak beginning in late November 2025. The investigation team collected nasopharyngeal swabs from 38 symptomatic camels during December 1–18, 2025, sampling animals with lacrimation, nasal discharge, and intermittent cough. Those 38 animals represented about 1.2% of the 3,190 camels registered in the affected rural district. Investigators extracted viral RNA and ran 1-step qRT-PCR assays targeting the upstream envelope (upE) and ORF1a genes. All 38 samples were positive for MERS-CoV by both assays. Cycle threshold values spanned 23.14–33.09 for upE (median 29.31) and 14.33–31.09 for ORF1a (median 25.89), indicating detectable viral RNA across symptomatic age groups. Follow-up sampling roughly four months later involved nasopharyngeal swabs and sera from 14 camels in previously affected herds; nasopharyngeal swabs were qRT-PCR–negative at that later point. The source did not report paired serologic results for those follow-up animals.
To confirm molecular identity, study authors amplified partial RNA-dependent RNA polymerase fragments from a subset of positive samples and sequenced selected amplicons. They generated one complete viral genome and four full-length spike gene sequences from outbreak-associated viruses. Whole-genome phylogenetic analysis placed the Kazakhstan genome within clade B5, clustering with recent camel-derived genomes from Saudi Arabia and Egypt (2023–2024). Spike gene phylogeny located the Kazakhstan sequences within the B5-2023.4 sublineage, forming a well-supported cluster with contemporary camel viruses from Saudi Arabia. The viruses from Kazakhstan carried spike substitutions P97L, G198D, and L495P—changes previously observed in B5-2023.4 sequences included in the analysis. The L450F substitution, reported in some recent viruses, was not identified among the public genomes compared in this study. The authors emphasized that available genomic data do not permit inference of viral phenotype or transmissibility.
The investigative team ran recombination analyses using Recombination Detection Program v4.101 and reported two putative recombination events involving the Kazakhstan genome that were supported by multiple detection methods. The inferred recombinant regions overlapped recombination signals previously documented among contemporary B5 viruses from Saudi Arabia. One inferred parental lineage could not be assigned with certainty. The source stated that additional complete genomes from the region are required to determine the frequency and evolutionary significance of these recombination events in Central Asia.
Clinical signs observed during the outbreak were similar across juveniles and adults and included ocular discharge, nasal discharge, and coughing. Affected animals were mainly dromedaries, though Bactrian camels in mixed herds were also symptomatic. The study team tested samples for other potential respiratory pathogens—molecular assays for influenza A and D viruses, bovine paramyxovirus, and herpesviruses—and those assays returned negative results in tested samples. The source did not provide detailed demographic breakdowns or attack-rate calculations beyond the proportion of registered camels sampled. Investigators reported no human MERS cases associated with this camel outbreak.
These molecular data extend documented MERS-CoV circulation into Central Asia and align Kazakhstan viruses with a lineage circulating in the Arabian Peninsula. The Mangystau region lies within livestock movement networks that connect Central Asia to neighboring regions, and the authors noted that animal movement and increasing connectivity could enable transboundary dissemination of zoonotic pathogens. The outbreak occurred during winter conditions, which contrasts with seasonal peaks often reported in warmer months in endemic settings; the source noted that whether climatic conditions alter viral stability, host susceptibility, or transmission dynamics in temperate continental environments remains unknown and warrants study. The genomic analysis revealed most spike substitutions matched contemporary B5-2023.4 viruses, but the biological implications of the identified substitutions and putative recombination events could not be resolved with the data available.
Limitations and outstanding questions documented by the study team include the limited number of complete genomes from Central Asia, absence of definitive assignment of a parental lineage for at least one recombinant segment, lack of data allowing inference of viral phenotype or transmissibility, and no reported human case linkage during this outbreak. The authors recommended expanded, coordinated molecular surveillance and genomic characterization of camel populations and exposed persons across Central Asia to define viral diversity, transmission dynamics, and potential public health risk more precisely.