Enterovirus G
LEVELS: Highly unlikely; No human illness; Already in the herd; Reference or research laboratory required; Minor; Negligible; Little; Available, or not needed
| Register id | enterovirus_g |
| Type | virus |
| Scientific name | Enterovirus G |
| NCBI taxid | 106966 |
| Evidence | 4 document(s) |
| Assigned | 2026-09-06, against criteria version 093366e352a2 |
Overview
Enterovirus G is a picornavirus found in domestic pigs and wild boar in the United States, Brazil, India, Thailand, China and Japan, and it appears to be a normal member of the healthy pig's gut virome — a Dutch study detected it in clinically healthy pigs from two weeks of age on all seven farms sampled, and a Japanese study recovered recombinant forms from 222 healthy faecal samples across 77 farms. Associations with skin lesions, fever and flaccid paralysis appear in the literature, but the reference chapter attributes no syndrome to it and explains the one historical link — the virus being recovered more often from unusual skin lesions than from faeces — as an artefact of it being picked up incidentally during investigations of swine vesicular disease. What has renewed interest in it is recombination: enterovirus G strains that have acquired a papain-like protease gene from a torovirus have been described, and these recombinants are being characterised by metagenomic sequencing rather than by any diagnostic assay. There is no treatment and no vaccine, and no human infection is described.
C1 Zoonotic potential
Likelihood of transmission from pigs to humans
Highly unlikely: Human infection with the agent has never been reported, or has been reported but is not attributed to pig or pork exposure
CONFIRMED by Eric. The assignment reached this level from the evidence, and he has reviewed and ratified it.
Confirmed by Eric. CONFIRMED. "c1l1, no evidence to suggest it is zoonotic"
Basis. ch36 36.9 covers enterovirus G in full and makes no mention of human infection. The types it lists occur in domestic pigs, wild boar, sheep and goats. shic_2021_porcine_sapelovirus (placed thin): "PSV does not infect humans." PSV "is closely related to members of the genera Teschovirus and Enterovirus and has previously been known as porcine enterovirus 8 (PEV-8)."
How this level was decided
INFERRED from the chapter structured silence, which gives an explicit public health statement to every agent that has one. Level 1. NOTE: these viruses were formerly called porcine enteroviruses, a name that invites confusion with the human enteroviruses -- ch36 36.4.9 records that no cross-neutralisation was found between EMCV and 62 human enterovirus serotypes or 11 porcine ones, which are separate agents. Level 1 confirmed for the enteric picornaviruses.
C2 Zoonotic impact
Severity of human illness caused by the agent
No human illness: Agent does not cause illness in people
CONFIRMED by Eric. The assignment reached this level from the evidence, and he has reviewed and ratified it.
Confirmed by Eric. CONFIRMED. "c2l1, no evidence to suggest it is zoonotic"
Basis. No human disease is described in ch36 36.9.
How this level was decided
INFERRED, on the same silence. C2 scores level 1 whenever the agent does not cause disease in people. Unchanged.
C3 Herd introduction risk
Effort required to keep the agent out of the herd
Already in the herd: Present in most herds, or carried by pigs themselves, so there is no introduction event to prevent
CONFIRMED by Eric. The assignment reached this level from the evidence, and he has reviewed and ratified it.
Confirmed by Eric. CONFIRMED. "c3l1, suspected to be present in many or most herds already, and not excludable"
Basis. de Groof 2025: "Rotavirus A, Porcine Kobuvirus, Enterovirus G and Porcine Astrovirus 3 and 4 were first detected at two weeks of age" in clinically healthy pigs across seven farms. Imai 2023 recovered recombinant EV-G from "222 healthy fecal samples from 77 pig farms in Japan". ch36 36.9 records EV-G in the US, India, Brazil, Thailand, China and Japan, in domestic pigs and wild boar. shic_2021_porcine_sapelovirus: "Many farm environments are likely contaminated with PSV." "PSV is hardy and likely persists in swine environments."
How this level was decided
Level 1 unchanged and now supported by two direct surveys rather than by extension from the group. Acquired at two weeks of age and recovered from healthy pigs on 77 farms in one country alone. No introduction event to prevent. Level 1 confirmed. The statement is made of the porcine enteric picornaviruses as a group, which is what this entry is.
C4 Detection difficulty
Difficulty of recognizing and confirming infection
Reference or research laboratory required: A validated assay exists, but only at a national reference or research laboratory rather than at local or regional level
CONFIRMED by Eric. The assignment reached this level from the evidence, and he has reviewed and ratified it.
Confirmed by Eric. "l3, assay is described but may not be readily available without access to reference lab or research lab"
Basis. ch36 36.5.8.1 describes "nested RT-PCR assays to specifically detect PTV-1 and to differentiate PTV, PSV, and PEVs from each other using virus-specific primer sets", all from research publications. Imai 2023 identified its recombinants by next-generation sequencing and metagenomic analysis, not by a diagnostic assay.
How this level was decided
MOVED L2 -> L3 on Eric's ruling of 2026-08-31: "l3, assay is described but may not be readily available without access to reference lab or research lab." Imai illustrates it -- the recombinants that paper reports were found by NGS, and a virus whose variants are discovered by sequencing is not one a local laboratory is confirming on request. Unchanged.
C5 Production cost
Financial impact on the infected farm's cost of production
Minor: Small and generally short-lived losses with little effect on overall cost of production
INFERRED — reasoned, not stated. The evidence implies this level rather than stating it. The reasoning is below.
Corrected by Eric from L1 Negligible. Reason: Eric, 2026-08-31: "make enterovirus_g C5L2." This SUPERSEDES his own confirmation of level 1 on 2026-08-29, which was made before imai_2023_evg_recombinants_japan was in the folder. That paper states "EV-Gs are associated with skin lesions, pyrexia, and flaccid paralysis in pigs" -- the first thing in this folder attributing disease to the agent, and something ch36 36.9 does not say. The pass held level 1 and flagged it rather than moving: the statement is a citation to other work rather than a finding of that study, whose own material was 222 healthy faecal samples from 77 farms, and degroof_2025 independently found EV-G to be a normal component of the healthy weaning virome from two weeks of age. He has ruled the other way. Level 2 records small and generally short-lived losses, which fits an agent that is ubiquitous in healthy pigs and occasionally associated with clinical signs -- and it stops ch36's dismissal of the historical skin-lesion association as adventitious from being the folder's last word on the question.
Basis. Imai 2023 states, citing other work: "EV-Gs are associated with skin lesions, pyrexia, and flaccid paralysis in pigs [16, 43]." Its own material was 222 HEALTHY faecal samples from 77 farms. de Groof 2025 found EV-G in clinically healthy pigs from two weeks of age on all seven farms. ch36 36.9 attributes no syndrome to EV-G and explains the one historical association -- higher recovery from atypical skin lesions than from faeces -- as adventitious isolation during SVDV investigations. shic_2021_porcine_sapelovirus: "Co-infection with other enteric pathogens often occurs." "PSV is commonly isolated from the intestinal tract of healthy swine, and it is often found with other enteric pathogens."
How this level was decided
Level 1 held, but FLAGGED FOR ERIC because the folder now contains something it did not when he confirmed this cell on 2026-08-29. Imai attributes skin lesions, pyrexia and flaccid paralysis to EV-Gs. Three things argue for holding at level 1 anyway: it is a citation to references 16 and 43 rather than a finding of that study, the study itself sampled only healthy pigs, and de Groof independently found the virus to be a normal component of the healthy weaning virome. It is nonetheless the first statement in this folder attributing disease to the agent, and the chapter's dismissal of the skin-lesion association as adventitious now has something standing against it. His call. Level 2 held, on Eric's ruling. The new source supports the reasoning behind it: these viruses are found together in healthy pigs, so attributing loss to any one of them is the standing difficulty.
C6 Market impact
Duration of material disruption to pork and pig markets
Negligible: Little or no material disruption to supply or demand when disease occurs on one or more farms
CONFIRMED by Eric. The assignment reached this level from the evidence, and he has reviewed and ratified it.
Confirmed by Eric. CONFIRMED. "c6l1, no evidence to suggest the market would have any response to a positive diagnosis"
Basis. Section 36.9 records no trade measure, movement control or consumer response.
How this level was decided
INFERRED. An agent present worldwide with no attributed disease and no regulatory status has no route to pork supply or demand. Level 1. Unchanged.
C7 Treatment potential
Potential for treatment to improve outcomes
Little: Effective pathogen-directed treatment is available and works, or animals recover acceptably without it
CONFIRMED by Eric. The assignment reached this level from the evidence, and he has reviewed and ratified it.
Confirmed by Eric. CONFIRMED. "c7l1, given we have little evidence it causes clinical disease, there is little imperative for development of a treatment"
Basis. No treatment is described in ch36 36.9. 36.5.10: "Potential antiviral chemotherapeutics for porcine enteric picornaviruses have received little attention."
How this level was decided
INFERRED. C7 asks how much better outcomes would be with a treatment and no adverse outcome is attributed to this agent, so there is nothing to improve. The second clause of level 1 -- animals do acceptably without treatment because there is no disease to recover from. Same shape as the campylobacter_spp call Eric confirmed. Unchanged.
C8 Vaccine availability
Availability of effective vaccines or bacterins
Available, or not needed: Effective vaccines are widely available in the US or secured for national outbreak response, or the disease does not clinically or economically justify vaccinating
CONFIRMED by Eric. The assignment reached this level from the evidence, and he has reviewed and ratified it.
Confirmed by Eric. CONFIRMED. "c8l1, given we have little evidence it causes clinical disease, there is little imperative for development of a vaccine"
Basis. No vaccine is described for enterovirus G in ch36 36.9.
How this level was decided
INFERRED. No vaccine exists and none is warranted for an agent with no attributed disease. Level 1 on the second clause. Unchanged.
Levels and evidence are generated from data/assignments/enterovirus_g.yml; the overview is authored in data/overviews/enterovirus_g.md. Do not hand-edit this page — corrections go in data/assignments/CORRECTIONS.yml.
Quoted material marked Basis is from Zimmerman JJ, Karriker LA, Ramirez A, Schwartz KJ, Stevenson GW, Zhang J, eds. Diseases of Swine, 12th edition. Hoboken: Wiley Blackwell, 2025 — except where another source is named in the quotation itself.