Encephalomyocarditis virus (EMCV): An overlooked threat to primates

Figures

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  Fig 1. Timeline summarizing key events related to the detection, isolation, and reported cases of encephalomyocarditis virus (EMCV) infection in human and nonhuman primates (NHPs). Created in BioRender. FENOLLAR, F. (2026) https://BioRender.com/cs8mssl.

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  Fig 2. Classification (A) and Genomic organization (B) of encephalomyocarditis virus (EMCV). The encephalomyocarditis virus (EMCV) belongs to the Picornaviridae family and the Cardiovirus genus. This genus is currently classified into six species according to the International Committee on Taxonomy of Viruses (ICTV): Cardiovirus A, which includes four serotypes of EMCV; Cardiovirus B, comprising 14 types, including Theiler’s murine encephalomyelitis virus (TMEV), Thera virus (TRV), Vilyuisk human encephalomyelitis virus (VHEV), and Saffold virus (SAFV); as well as Cardiovirus C (3 types), Cardiovirus D (11 types), Cardiovirus E (1 type), and Cardiovirus F (1 type). In the diagram, solid lines and borders represent well-established taxonomic classifications and verified serotypes, whereas dashed lines and borders indicate species or serotypes whose classification is currently under debate within the scientific community. Created in BioRender. FENOLLAR, F. (2026) https://BioRender.com/mkgj9xa.

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  Fig 3. Global distribution of cumulative encephalomyocarditis virus cases reported in NHPs from 1944 to 2025. The colored areas (red, blue, orange, and cyan) indicate the geographical regions where EMCV cases have been reported in NHPs and the virus isolation. The most significant cases have been reported in the USA and Russia. Map created with Datawrapper; base map layer (administrative boundaries) provided by Natural Earth (https://www.naturalearthdata.com).

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  Fig 4. Reservoir hosts and transmission cycle of encephalomyocarditis virus. This diagram illustrates the multi-host ecology of EMCV, where rodents serve as the primary natural reservoirs maintaining the virus within the natural ecosystem through persistent infections, with bats also potentially involved in this maintenance. Transmission to other species occurs via two main reported pathways: the ingestion of food or water contaminated with rodent excreta or secretions, and the consumption of infected rodent carcasses. The potential role of arthropod vectors (mosquitoes and Acarina) in transovarian or transstadial transmission remains a hypothesis requiring further investigation. A wide range of susceptible hosts can be infected, including domestic pigs, various wild and captive animals (such as primates and elephants), and highly sensitive rodents like mice, while humans are considered accidental hosts. In the diagram, solid lines represent reported and verified transmission routes, while dashed lines indicate plausible hypotheses. Created in BioRender. FENOLLAR, F. (2026) https://BioRender.com/cxhowt9.