Dengue virus
LEVELS: Highly unlikely; Moderate; Extraordinary biosecurity required; Reference or research laboratory required; Negligible; NOT ASSIGNED; Little; Available, or not needed
| Register id | dengue_virus |
| Type | virus |
| Scientific name | Dengue virus |
| NCBI taxid | 12637 |
| Evidence | 1 document(s) |
| Assigned | 2026-09-04, against criteria version 093366e352a2 |
Overview
Dengue virus is one of the most important human arboviruses in the world — found throughout the tropics, with almost 400 million infections in 2010 alone — and pigs appear to have nothing to do with it. No natural infection of a pig has ever been reported. The entire evidence base is a single experimental line of work in which Yucatan miniature pigs inoculated subcutaneously or intravenously produced neutralising antibody, with virus detectable in the blood only by the subcutaneous route; on re-challenge those pigs developed a rash and skin swelling suggestive of antibody-dependent enhancement, which is a phenomenon of interest to dengue vaccinology rather than to pig health. The reference chapter's general position on the flaviviruses other than Japanese encephalitis and West Nile is that pigs are unlikely to be involved in their transmission cycles. There is no diagnostic approach described for dengue in pigs, no disease, no treatment and no vaccine. The entry exists to record that absence deliberately rather than by omission.
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
Basis. ch30 30.3.3 describes dengue in pigs only experimentally: "Yucatan miniature pigs infected with DENV1 via the SC or intravenous routes produced neutralizing antibodies; however, viremia was only observed following SC infection." No natural infection of pigs is reported anywhere in the chapter, and 30.3 states of the other orthoflaviviruses generally that "it is considered unlikely that pigs are involved in the transmission cycles of these viruses".
How this level was decided
Level 1. Dengue is maintained in a human-mosquito-human cycle with no established non-primate reservoir, and the chapter records no natural infection of pigs at all -- only deliberate subcutaneous and intravenous inoculation of miniature pigs in a laboratory. There is no evidence that pigs transmit the agent to humans, which is the level 1 test. NOTE ON WHAT THIS ENTRY IS. Chapter 30 discusses this virus almost entirely as an ANIMAL MODEL -- "Pigs have been used to develop animal models of human infections caused by DENV and ZIKV... make pigs an attractive alternative to nonhuman primates for studying human infectious diseases". A pig deliberately inoculated in a laboratory is not a pig disease, and this assessment scores only what the folder says about natural infection.
C2 Zoonotic impact
Severity of human illness caused by the agent
Moderate: Clinically important illness is common and may require medical treatment or hospitalization, but death or permanent disability is uncommon
Basis. ch30 30.3.3: "DENV is found throughout tropical regions of the world. In 2010, almost 400 million infections occurred." No pig-to-human transmission is described.
How this level was decided
RE-SCORED 2026-09-04. C2 now grades the severity of the illness the agent causes in a person, independent of how the person was exposed -- the 2026-09-01 pig-attribution reading is reversed, and C1 alone carries the source question. Clinically important illness requiring medical care is common; severe dengue is life-threatening but is the tail, and the C2 rule is the typical-to-severe bout. Level 3 rather than 4 on that reading.
PREVIOUS ANSWER, written under the pig-attribution reading: Level 1 under the criterion as rescoped on 2026-09-01: C2 grades illness acquired FROM PIGS, and C1 is level 1 because the pig is not a source. THE LABEL MUST NOT BE READ AS A FINDING THAT DENGUE IS MILD -- it is a major human disease with hundreds of millions of infections a year, including severe haemorrhagic forms. It records that a pig is not where a person gets it.
C3 Herd introduction risk
Effort required to keep the agent out of the herd
Extraordinary biosecurity required: Exclusion needs measures beyond the routine, such as air filtration, thermally treated feed and bedding, or repeated costly testing to find carriers, and may still fail
CONFIRMED by Eric. The assignment reached this level from the evidence, and he has reviewed and ratified it.
Confirmed by Eric. CONFIRMED. "c3l5, given we have competent vectors in the US, other criteria should rightfully reduce overall ranking probably to the 'NOT ASSessed' KISS level" RESCALED 2026-09-03, when C3 went from five levels to four and level 4 absorbed level 5. A ruling of his is never overturned by a scale change, so what is recorded here is the same judgment expressed on the new scale. AND THE ENTRY ALSO MOVED, on the pass Eric approved the same day: the whole old level 5 block was re-read against the exclusion test rather than the reservoir test, because twenty-one of those entries had been renumbered past the housing level on 2026-09-01 without being judged against it. See the entry justification for the reason this one moved. Recorded on the old scale as level 5, from_level 5.
Basis. ch30 30.3.3: DENV "is found throughout tropical regions of the world" and is transmitted by Aedes mosquitoes. 30.1 lists dengue among the "important arthropod-borne pathogens of humans and animals" in the genus. The chapter describes no route by which pigs acquire DENV naturally.
How this level was decided
RENUMBERED L5 -> L4 on 2026-09-03, when C3 was reduced from five levels to four and level 4 absorbed level 5. THE JUDGMENT IS UNCHANGED and this one really is a renumber: the merged level 4 label carries what level 5 said, ending "and may still fail". IT WAS STILL CHECKED rather than assumed, because the last renumber on 2026-09-01 was mechanical and moved twenty-one entries past a level they should have been judged against. The check is the exclusion test -- does housing close the route? For this entry it does not.
EARLIER REASONING, kept because it is the evidence read: INFERRED, AND FLAGGED AS THE WEAKEST CELL IN THE ENTRY. If a pig can be infected at all, the route is a mosquito bite, the reservoir is the human population, and neither is removable by any farm or industry action -- which is level 5. But the chapter records no natural pig infection, so what is being scored is the introduction risk of an agent that may not establish in pigs at all. Level 5 is scored on the highest-level-wins rule; NOT ASSESSED is defensible if Eric judges that an agent with no documented natural infection has no introduction risk to score.
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. CONFIRMED. "c4l3, many tests available for dengue - PCR would certainly work though perhaps not serology"
Basis. Chapter 30 describes no diagnostic approach for dengue in pigs. 30.3.1, on the related viruses, records that serological interpretation must account for "cross-reactions to closely related orthoflaviviruses" and that resolving them requires virus neutralisation.
How this level was decided
INFERRED from the serogroup rather than from anything specific to dengue in pigs. Validated dengue assays exist and are excellent, because dengue is a major human disease -- so this is not level 4. But they are human-diagnostic assays held by public health laboratories, no veterinary laboratory would run one on a pig, and nothing clinical would prompt the request. Level 3.
C5 Production cost
Financial impact on the infected farm's cost of production
Negligible: No measurable effect on cost of production
Basis. ch30 30.3.3 reports no natural dengue infection of pigs and no clinical disease. The only findings are experimental: subcutaneously inoculated Yucatan miniature pigs re-challenged with DENV1 showed "rash and dermal edema... suggestive of antibody-dependent enhancement".
How this level was decided
Level 1. No natural infection, no field disease, no reported loss. The rash and oedema seen on experimental re-challenge is a laboratory model of a human phenomenon rather than a swine disease. No measurable effect on cost of production. NOTE ON WHAT THIS ENTRY IS. Chapter 30 discusses this virus almost entirely as an ANIMAL MODEL -- "Pigs have been used to develop animal models of human infections caused by DENV and ZIKV... make pigs an attractive alternative to nonhuman primates for studying human infectious diseases". A pig deliberately inoculated in a laboratory is not a pig disease, and this assessment scores only what the folder says about natural infection.
C6 Market impact
Duration of material disruption to pork and pig markets
NOT ASSESSED — no evidence in folder. No level was assigned on this criterion. This is a statement about what the evidence folder holds, not a finding about the agent.
Corrected by Eric from L1 Negligible. Reason: CONFIRMED AS NOT ASSESSABLE. "I think we have to make this not assessed because we really don't know, a bit like Hendra which I think we scored teh same way." He is right about Hendra -- he ruled its C6 unassessable on 2026-08-26 and ross_river_virus the same way on 2026-08-31. The assessment had scored level 1 on the ground that a virus which does not naturally infect pigs has no route to the pork market. He is overriding that: dengue has never naturally infected a pig anywhere, so there is no precedent of any kind to reason from, and level 1 would confidently assert that nothing would happen. NOTE THE CONTRAST WITH ZIKA, which he confirmed at C6 level 1 in the same round with "relying on experience from other countries it is unlikely there will be a market effect" -- pigs ARE naturally infected with Zika abroad, so there is an observed precedent. The distinction is whether anything has ever been observed, not whether the agent is exotic.
Basis. Section 30.3.3 records no trade measure, movement control or consumer response, and dengue is not among the orthoflaviviruses ch30 30.1 identifies as WOAH-listed.
How this level was decided
INFERRED. A virus that does not naturally infect pigs, is not WOAH-listed and causes no swine disease has no route to pork supply or demand. Level 1.
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, the risk of pigs becoming must be low given the paucity of info in the literature even though the disease and pigs overlap throughout asia. I think there would be little imperative to invest in treatmetn for dengue in pigs"
Basis. Chapter 30 describes no treatment for dengue in pigs, and no disease in pigs for a treatment to address.
How this level was decided
INFERRED. Under the standing note SCORING/treatment_potential, level 1 covers the case where there is no imperative to treat, and here there is no documented natural disease at all. Level 1 on the second clause.
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, as with treatment it seems like there would be little imperative to invest in a dengue vaccine for pigs"
Basis. No swine dengue vaccine is described in ch30 30.3.3, and no swine disease is described for one to prevent.
How this level was decided
INFERRED. No vaccine exists for pigs, and under the reworded criterion the question is whether one is warranted. For a virus with no documented natural infection of pigs it is not. Level 1 on the second clause.
Levels and evidence are generated from data/assignments/dengue_virus.yml; the overview is authored in data/overviews/dengue_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.