Porcine Sapelovirus
LEVELS: Highly unlikely; No human illness; Already in the herd; Reference or research laboratory required; Minor; Negligible; Little; Available, or not needed
| Register id | porcine_sapelovirus |
| Type | virus |
| Scientific name | Sapelovirus A |
| NCBI taxid | 686984 |
| Evidence | 3 document(s) |
| Assigned | 2026-09-06, against criteria version 093366e352a2 |
Overview
Porcine sapelovirus is a picornavirus detected in pig herds worldwide, including in the United States, where one survey recovered it from 44% of faecal samples. It is part of the normal gut virome of healthy pigs — a Dutch study of clinically healthy animals on seven commercial farms found it before weaning, with the amount of virus peaking a week afterwards — so its presence in a sample does not explain a case. There is, however, good experimental evidence that it can cause disease: a Korean strain induced diarrhoea and intestinal damage in inoculated piglets, a Chinese strain produced severe diarrhoea, and sapelovirus antigen has been found within spinal cord lesions in pigs with ataxia, which is the basis for its association with neurological disease. Detecting it is a research exercise — six different molecular assays have been published, all from individual laboratories, with no commercial product. No antiviral and no vaccine exists, and antiviral chemotherapy for the porcine enteric picornaviruses as a group has received very little attention. 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 that it is zoonotic"
Basis. ch36 36.8 covers porcine sapelovirus in full and makes no mention of human infection. Its only non-porcine relatives named are simian picornaviruses in a separate species, Sapelovirus besimi. Chapter 36 states the human position explicitly wherever there is one -- for FMDV, SVDV, EMCV, PTV and SVV. shic_2021_porcine_sapelovirus: "PSV does not infect humans." "Domestic and wild swine are the only known hosts for PSV."
How this level was decided
INFERRED from a structured silence. This chapter is consistent about giving each agent a public health statement where one is warranted, and the sapelovirus section has none. Level 1. Level 1 confirmed twice.
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 that it is zoonotic"
Basis. No human disease is described in ch36 36.8. shic_2021_porcine_sapelovirus: "PSV does not infect humans."
How this level was decided
INFERRED, on the same silence. C2 scores level 1 whenever the agent does not cause disease in people. Level 1 confirmed.
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, likely already to be widespread and not causing significant disease"
Basis. de Groof 2025: "Although Rotavirus B & C, Porcine Sapelovirus and Porcine Sapovirus were already detected just before weaning, the amount of virus peaked one week after weaning", in clinically healthy pigs on seven commercial farms. ch36 36.8: PSVs "have been detected in pig herds worldwide", and 36.9 cites a survey recovering PSV from 44% of faecal samples. shic_2021_porcine_sapelovirus: "Many farm environments are likely contaminated with PSV." "PSV is stable in the environment, and resistant to elevated temperatures and acid pH." "In the United States, 32% of fecal samples from diarrheic pigs were PSV-positive." "PSV is hardy and likely persists in swine environments."
How this level was decided
Level 1 unchanged and now supported by direct observation rather than by extension from the group. Present before weaning and peaking a week after it, in herds selected for having almost no post-weaning diarrhoea. Carried by the pigs, so no introduction event to prevent. Level 1 confirmed and now well supported: a third of US diarrhoeic samples positive, and the factsheet's own statement that many farm environments are likely contaminated.
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, primers described but test would not necessarily be available at all local/regional labs"
Basis. ch36 36.8 lists six molecular assays for PSV -- real-time RT-PCR, nested, multiplex, multiplex real-time, minor groove binder real-time, and RT-LAMP -- plus serological tests, all from individual research publications. de Groof 2025 likewise ran its own RT-qPCR rather than a commercial assay. shic_2021_porcine_sapelovirus: "reverse-transcriptase polymerase chain reaction (RT-PCR) assays are most often used to detect PSV. Most assays target the 5UTR or VP1 region." "A VP2-VP1-based indirect enzyme-linked immunosorbent assay (ELISA) has been described for use with serum and oral fluids." "PSV can be cultured in many different cell lines."
How this level was decided
MOVED L2 -> L3 on Eric's ruling of 2026-08-31: "l3, primers described but test would not necessarily be available at all local/regional labs." Six published assays is not the same as one available assay -- the multiplicity is itself the signal, because each group builds its own. The previous score read the number of described assays as evidence of availability, which is the confusion the reworded criterion removes. Level 3 held. Assays exist and PSV cultures readily, so not level 4 -- but these are research-setting methods rather than anything on a routine diagnostic panel, and the factsheet frames the whole entry as an agent whose significance is unresolved, which is not something a local laboratory is asked to test for.
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
CONFIRMED by Eric. The assignment reached this level from the evidence, and he has reviewed and ratified it.
Confirmed by Eric. CONFIRMED. "c5l2, likely to be able to cause some clinical signs though other co- factors may be required but should not be considered l1 for this reason"
Basis. de Groof 2025 finds PSV in clinically healthy pigs on all farms, peaking a week after weaning. Against that, ch36 36.8 records causation established experimentally: "A Korean PSV strain has been shown to induce diarrhea and intestinal pathology in experimentally inoculated piglets, and experimental studies with a Chinese strain produced severe diarrhea", plus PSV antigen co-localised in spinal cord lesions of ataxic pigs. shic_2021_porcine_sapelovirus: "PSV infections are often subclinical." "An outbreak of polioencephalomyelitis occurred in U.S. swine, with reported morbidity and case fatality rates of 20% and 30%, respectively. Intravaginal and intrauterine inoculation of gilts at day 30 of gestation leads to 94% fetal mortality." "Co-infection with other infectious agents is common, and to date, the importance of PSV as a swine pathogen remains unclear."
How this level was decided
Level 2 unchanged, and the new paper sharpens rather than moves it. Healthy-pig carriage is now demonstrated rather than assumed, which caps how much disease can be attributed -- but unlike porcine_kobuvirus, causation here is established, not merely proposed: inoculation reproduced severe diarrhoea and viral antigen sits inside the spinal cord lesions. So this does not follow kobuvirus down to level 1. INFERRED still, because a healthy-pig survey cannot say how often the experimental disease occurs in the field, which remains the unmeasured quantity. Level 2 held, though the range in the new source is wide enough to note. A US polioencephalomyelitis outbreak with 20% morbidity and 30% case fatality is a real event, and 94% fetal mortality on experimental inoculation is striking -- but the factsheet's own conclusion is that PSV is commonly isolated from healthy pigs, co-infection is usual, and its importance as a primary pathogen is unclear. The typical situation for the entry is subclinical carriage.
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 that previous diagnoses has created any influence on markets"
Basis. Section 36.8 records no trade measure, movement control or consumer response. PSV is detected in pig herds worldwide including the US. shic_2021_porcine_sapelovirus: "PSV is not an OIE-listed disease. There are no restrictions for importation of animals from countries or zones affected by PSV."
How this level was decided
INFERRED. Under the standing note SCORING/market_impact, an agent already present worldwide and diagnosed without any market response scores level 1. Level 1 confirmed on a direct statement.
C7 Treatment potential
Potential for treatment to improve outcomes
Little: Effective pathogen-directed treatment is available and works, or animals recover acceptably without it
INFERRED — reasoned, not stated. The evidence implies this level rather than stating it. The reasoning is below.
Corrected by Eric from L2 Some. Reason: MOVED L2 -> L1. "c7l1, am downgrading as there seems to be little clincial imperative to invest in treatment." The pass held L2 on the extralabel reading. His ruling takes the other clause of the standing note -- level 1 where there is no imperative to treat at all -- and the SHIC factsheet supports it: PSV infections are often subclinical, it is commonly isolated from the intestinal tract of healthy swine, co-infection is usual, and the factsheet's own conclusion is that "the importance of PSV as a swine pathogen remains unclear".
Basis. No antiviral or therapeutic is described in ch36 36.8. ch36 36.5.10, on this group: "Potential antiviral chemotherapeutics for porcine enteric picornaviruses have received little attention." shic_2021_porcine_sapelovirus: "There is no treatment for pigs infected with PSV."
How this level was decided
INFERRED. No pathogen-directed treatment exists and the chapter says the field has barely looked. Unlike teschovirus_a and the other subclinical picornaviruses, this agent has demonstrated disease -- experimentally reproduced severe diarrhoea, and myelitis with antigen in the lesion -- so the second clause of level 1 does not hold: there are real outcomes a treatment could improve. Scored level 2 rather than 3 because supportive care and the broad management measures used against enteric disease do reach some of it, and because the field burden is unquantified. FLAGGED as a judgment between 2 and 3. Level 2 held.
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, today there is not evidence that disease is frequent or severe enough to warrant investment in a vaccine. This however is a bit in contrast to the answer we gave for c7 above."
Basis. No vaccine is described for PSV in ch36 36.8. shic_2021_porcine_sapelovirus: "There are no sapelovirus vaccines." "More research is needed to determine its importance as a primary pathogen, and vaccine development should be explored."
How this level was decided
INFERRED. No vaccine exists, and the reworded criterion asks whether one is warranted. The chapter establishes that PSV can cause disease experimentally but gives no field prevalence of disease against worldwide detection in healthy pigs, so there is no demonstrated unmet need to record. Level 1 on the second clause. FLAGGED: if the spinal cord and diarrhoea findings represent a real field burden, this is level 3. Level 1 held, but noting the pull the other way: the factsheet itself says vaccine development should be explored. Under the standing note that is not enough for level 3, which is reserved for a disease that WOULD warrant a vaccine -- and the same paragraph says PSV's importance as a primary pathogen is still unclear. A recommendation to explore is not a demonstrated gap.
Levels and evidence are generated from data/assignments/porcine_sapelovirus.yml; the overview is authored in data/overviews/porcine_sapelovirus.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.