Valovirus valerienense (St-Valérien-like virus)

LEVELS: Highly unlikely; No human illness; Already in the herd; No validated assay; Negligible; Negligible; Little; Available, or not needed


Register id	`saint_valerien_like_virus`
Type	virus
Scientific name	Valovirus valerienense
NCBI taxid	3433097
Evidence	1 document(s)
Assigned	2026-09-04, against criteria version `093366e352a2`

Overview

The Saint-Valérien-like viruses are a small group of caliciviruses first reported in 2009 from pigs sampled in Quebec between 2005 and 2007, and now classified in a genus of their own, Valovirus, sitting close to the noroviruses. They have since been found in the United States as well. That is very nearly the whole of what is known: the reference chapter gives the agent one paragraph — the shortest treatment of any entry on this register — describing the genome and where the virus sits on the phylogenetic tree, and nothing about what it does. No disease has been attributed to it, no clinical case is described, no diagnostic assay is offered outside the original sequencing work, and there is no treatment or vaccine. It is on the register because it is a recognised porcine calicivirus, and its place here is essentially a placeholder against the possibility that it turns out to matter.

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 evidenced of zoonotic transmission"

Basis. ch26 26.4 IS THE ENTIRE SECTION ON THIS AGENT -- one paragraph, and the shortest treatment any entry in this batch gets: "In 2009, a report described a novel calicivirus (Saint Valerien virus) isolated from pigs in Quebec, Canada, between 2005 and 2007. Genomic analysis revealed a positive-sense RNA genome of 6409 nucleotides encoding two major ORFs. Phylogenetic analysis showed that these viruses form a unique cluster with a common root with the noroviruses and the Tulane virus isolated from captive juvenile Rhesus macaques. These viruses have now been placed in a new genus Valovirus containing a single species Valovirus valerienense. VALOVIRUSES HAVE ALSO BEEN FOUND IN THE UNITED STATES, Italy, and Japan. In a study in Italy, 10.3% OF 614 PIGS HAD ANTIBODIES to Saint Valerien virus. THE ROLE OF SAINT VALERIEN VIRUS IN SWINE DISEASE IS UNKNOWN. Based on unpublished GenBank submissions, related viruses have been identified in rabbits in Australia and stoats in the United Kingdom." The chapter gives Public Health sections to vesicular exanthema (26.2.3), porcine noroviruses (26.3.2.2) and porcine sapoviruses (26.3.3.2), and none to the valoviruses. Its blanket statement at 26.3.1 covers the group: "Based on limited data, there is no clear evidence that KNOWN PORCINE CALICIVIRUSES pose a threat to human health." The only related hosts named for this genus are rabbits and stoats.

How this level was decided

INFERRED FROM A STRUCTURED SILENCE, and the silence here is of the informative kind rather than the empty kind. Chapter 26 raises public health three separate times, in a dedicated numbered section each time, including for the two agents whose human relatives cause gastroenteritis -- so its authors plainly write about the human question wherever they think one exists. They did not write one here, and the only other hosts they name for the genus are rabbits and stoats. FLAGGED HONESTLY: this is an inference from what the chapter chose to discuss, not from anything it says about this virus, and the entry rests on a single paragraph. It moves if the folder ever gains a source that engages with the question.

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 of zoonotic transmission"

Basis. No human illness with Saint Valerien virus is described anywhere in chapter 26, and the chapter gives the genus no public health section.

How this level was decided

INFERRED, following C1. Under C2 as rescoped, level 1 means pigs are not a source of human illness with this agent, and nothing in the folder says otherwise. It moves with C1.

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, no systematic surveillance conducted but some evidence that the agent is already on farms and no information to suggest there is a need to try to exclude it"

Basis. ch26 26.4 IS THE ENTIRE SECTION ON THIS AGENT -- one paragraph, and the shortest treatment any entry in this batch gets: "In 2009, a report described a novel calicivirus (Saint Valerien virus) isolated from pigs in Quebec, Canada, between 2005 and 2007. Genomic analysis revealed a positive-sense RNA genome of 6409 nucleotides encoding two major ORFs. Phylogenetic analysis showed that these viruses form a unique cluster with a common root with the noroviruses and the Tulane virus isolated from captive juvenile Rhesus macaques. These viruses have now been placed in a new genus Valovirus containing a single species Valovirus valerienense. VALOVIRUSES HAVE ALSO BEEN FOUND IN THE UNITED STATES, Italy, and Japan. In a study in Italy, 10.3% OF 614 PIGS HAD ANTIBODIES to Saint Valerien virus. THE ROLE OF SAINT VALERIEN VIRUS IN SWINE DISEASE IS UNKNOWN. Based on unpublished GenBank submissions, related viruses have been identified in rabbits in Australia and stoats in the United Kingdom." For the family generally, 26.1: "caliciviruses are STABLE IN THE ENVIRONMENT, and many strains are resistant to inactivation by heat and certain chemicals", and "enteric caliciviruses are ACID STABLE". For the two enteric genera in the chapter, 26.3.2.6 and 26.3.3.9 both conclude that the viruses "persist in the environment and IT MAY BE IMPOSSIBLE TO ELIMINATE THE INFECTION FROM PIG HERDS and prevent natural infection of piglets".

How this level was decided

INFERRED, and inferred from the family rather than from the entry, which is why the support flag says so. What is known about this virus is that it is an acid-stable, environmentally resistant enteric calicivirus, found in pigs on four continents including the United States, with 10.3% of 614 Italian pigs carrying antibody -- and that its two nearest relatives in the same chapter are both agents the authors say cannot be kept out of a herd or off a piglet. Level 1 follows: there is no introduction event to prevent for an enteric calicivirus that is already here. FLAGGED because 10.3% seroprevalence in one Italian survey is thinner support than the 97% and 83% figures that put porcine norovirus and sapovirus at the same level, and because no US prevalence figure exists at all.

C4 Detection difficulty

Difficulty of recognizing and confirming infection

No validated assay: No pathogen-specific test of known reliability exists anywhere, and identification depends on sequencing or on primers that have not been critically evaluated

Basis. ch26 26.4 IS THE ENTIRE SECTION ON THIS AGENT -- one paragraph, and the shortest treatment any entry in this batch gets: "In 2009, a report described a novel calicivirus (Saint Valerien virus) isolated from pigs in Quebec, Canada, between 2005 and 2007. Genomic analysis revealed a positive-sense RNA genome of 6409 nucleotides encoding two major ORFs. Phylogenetic analysis showed that these viruses form a unique cluster with a common root with the noroviruses and the Tulane virus isolated from captive juvenile Rhesus macaques. These viruses have now been placed in a new genus Valovirus containing a single species Valovirus valerienense. VALOVIRUSES HAVE ALSO BEEN FOUND IN THE UNITED STATES, Italy, and Japan. In a study in Italy, 10.3% OF 614 PIGS HAD ANTIBODIES to Saint Valerien virus. THE ROLE OF SAINT VALERIEN VIRUS IN SWINE DISEASE IS UNKNOWN. Based on unpublished GenBank submissions, related viruses have been identified in rabbits in Australia and stoats in the United Kingdom." No diagnostic method is described for this agent anywhere in the chapter. The original identification was by genome sequencing, and the only other assay referred to is the serological survey behind the 10.3% figure. Compare 26.3.2.5 and 26.3.3.7, where the chapter states for the two better-studied enteric caliciviruses that no test exists for use outside a research laboratory and that the sensitivity of the molecular tests has not been evaluated.

How this level was decided

Level 4, and this is the straightforward reading rather than an inference. Under the 2026-08-29 rewording the axis is whether a validated assay exists and where it can be run, and for this agent the chapter describes no assay at all -- identification was by sequencing, which is the level 4 label in terms. Its two better-characterised relatives in the same chapter, porcine norovirus and porcine sapovirus, are the framework's worked examples at level 4 despite having published primer sets and, for sapovirus, ELISAs and a cultivable prototype. An agent with less than either cannot sit higher.

C5 Production cost

Financial impact on the infected farm's cost of production

Negligible: No measurable effect on cost of production

Corrected by Eric from no level assigned. Reason: "c5l1, diagnosticians and researchers have looked at the viral biome of thousands of pigs at this point, with and without disease and there is no evidence this agent is associated with significant clinical disease"

How this level was decided

NOT ASSESSED, and deliberately so. The chapter says in six words that the role of Saint Valerien virus in swine disease is unknown, and there is nothing else in the folder. That is an absence of evidence rather than an examined negative, and the difference matters: porcine norovirus is scored level 1 on C5 because every field detection was in a pig with NO CLINICAL SIGNS, which is a finding; here nobody has looked. NULLS STAY NULL -- a level imputed to make the entry exportable would be indistinguishable from a real one, and 1000minds accepts no empty cells, so this entry is correctly unexportable until the question is answered. This follows the pattern already set for porcine_tottorivirus, whose C5 and C7 are null for the same reason.

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 diagnosis will affect markets"

Basis. Valoviruses "have also been found in the United States", and no trade measure, movement control or consumer response is recorded anywhere in chapter 26.

How this level was decided

INFERRED. The standing note SCORING/market_impact draws the line at whether anything has ever been observed: where an agent is already present in US pigs and no market move has followed, that absence is evidence and the level is 1; where nothing has ever been observed anywhere and the event would be conspicuous, the cell is left unassessed. This agent has been in US pigs since at least 2011 with no market consequence of any kind, so it falls on the scoreable side. It is also the reason C6 is scored while C5 and C7 are not: silence about the market is informative here, silence about the clinical role is not.

C7 Treatment potential

Potential for treatment to improve outcomes

Little: Effective pathogen-directed treatment is available and works, or animals recover acceptably without it

Corrected by Eric from no level assigned. Reason: "c7l1, no clinical or market imperative to develop a treatment"

How this level was decided

NOT ASSESSED. C7 asks whether outcomes would meaningfully improve if a treatment existed, and that question cannot be answered for an agent whose role in disease is unknown -- there is no outcome on record to improve or to rule out. Scoring level 1 here would assert that the pigs recover acceptably without treatment, which nobody has established, and Eric's 2026-09-02 rule forbids the other easy answer as well: that nobody treats viral disease is the prevailing opinion the criterion is measuring against, not evidence about the answer. This cell moves when C5 does.

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, no clinical or market imperative to develop a vaccine"

Basis. No vaccine for Saint Valerien virus is mentioned anywhere in chapter 26, and none would be expected for an agent described in one paragraph whose role in disease is unknown.

How this level was decided

INFERRED at level 1 on the "not needed" clause. This is the one cell of the three where the unknown role can still be scored, and the reason is the shape of the C8 test after the 2026-08-28 rewording: level 3 is reserved for a GENUINE GAP, meaning no vaccine AND a disease that would warrant one, so an agent not shown to cause disease cannot reach level 3. Level 1 records that nothing currently justifies a vaccine, which is a statement about the state of knowledge and is true. NOTE THE ASYMMETRY WITH C5 AND C7, which are left null: those criteria would have to assert something about the disease to be scored at all, and this one does not.

Levels and evidence are generated from data/assignments/saint_valerien_like_virus.yml; the overview is authored in data/overviews/saint_valerien_like_virus.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.

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