Porcine Adenoviruses
LEVELS: Highly unlikely; No human illness; Already in the herd; Laboratory-dependent; Negligible; Negligible; Little; Available, or not needed
| Register id | porcine_adenoviruses |
| Type | virus |
| Scientific name | Porcine adenovirus |
| NCBI taxid | 114326 |
| Evidence | 2 document(s) |
| Assigned | 2026-09-06, against criteria version 093366e352a2 |
Overview
This entry groups the five porcine adenovirus serotypes as one unit. Pigs are the only species known to be susceptible to them, and they are ubiquitous — serological surveys report 23-60% of adult pigs with antibody. They are found most often in weaned pigs and rarely in adults, with faecal shedding continuing for up to fourteen weeks after weaning, and they are fairly stable outside the pig, surviving at room temperature for up to ten days. Clinically they amount to very little: infections are subclinical to mild, of low to moderate pathogenicity, and rarely cause disease of economic consequence. Where signs occur they are diarrhoea, mild dehydration, loss of appetite and reduced weight gain, and deaths are rare. Adenovirus is worth considering in the differential for enteric and respiratory disease, and unlike many of the viruses on this register it is readily grown in cell culture from faeces, gut contents, lung or kidney, though serotyping is seldom attempted for want of type-specific antisera. Control is biosecurity and sanitation. The reference chapter states the vaccine position plainly: because the infections are so mild, there is little incentive to produce one. They have no known public health significance.
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. ch41 41.1.1: "PAdVs are not known to have public health significance." 41.1.2: "Swine are the only known species susceptible to PAdV. PAdV is not contagious to humans, but swine can be experimentally infected with human adenovirus." shic_padv: "PAdVs are not known to infect humans." "Adenoviruses are relatively host-specific and pigs are the only known hosts for PAdV."
How this level was decided
Stated twice and from both directions -- pigs are the only susceptible species, and the traffic that has been shown runs the other way, human adenovirus into pigs. Level 1. Level 1 confirmed.
C2 Zoonotic impact
Severity of human illness caused by the agent
No human illness: Agent does not cause illness in people
Basis. ch41 41.1.1: "PAdVs are not known to have public health significance." shic_padv: "PAdVs are not known to infect humans."
How this level was decided
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
Basis. ch41 41.1.2: "Swine are the only known species susceptible to PAdV." Serological surveys report 23-60% of adult swine with antibodies in England, and PAdVs are "most frequently detected in weaned pigs and rarely in adult animals", with faecal shedding continuing "up to 14 weeks post weaning". "PAdVs are relatively stable, resisting inactivation at room temperature for up to 10 days." shic_padv: "the virus is suspected to be widespread in domestic swine populations." "Serological surveys from Canada and England in the 1960s-1970s indicated that up to 60% of swine test positive for anti-PAdV antibodies." "PAdV generally causes subclinical infections, and is commonly isolated from the gastrointestinal tract of normal swine." "Most adult swine are seropositive to adenovirus."
How this level was decided
Carried by the pigs and cycling through each weaned group as maternal antibody wanes, with no host outside swine to reintroduce it. There is no introduction event to prevent. Level 1. Level 1 confirmed. Note the caveat the factsheet supplies itself -- "current seroprevalence data is lacking", the surveys being sixty years old -- but it is corroborated by routine isolation from normal pigs and near-universal adult seropositivity, so the level does not rest on the old surveys alone.
C4 Detection difficulty
Difficulty of recognizing and confirming infection
Laboratory-dependent: The presentation does not point to this disease specifically, but local or regional laboratories can confirm it with a validated assay once it is suspected
Basis. ch41 41.1.4: "PAdV should be considered in the differential diagnosis of enteric and respiratory diseases in pigs." "PAdV can be readily isolated in cell culture from fecal samples, intestinal contents, or homogenates of lung or kidney using primary porcine kidney or continuous porcine kidney cells (PK-15)." "PCR and real-time quantitative PCR (qPCR) have been developed for the detection of PAdV in feces." But serotyping by virus neutralisation "is rarely done due to the lack of available type-specific antisera". shic_padv: "PAdV is easily cultured." "Immunofluorescence antibody (IFA) assays, complement fixation, direct fluorescence antibody (FA), and gel diffusion precipitation tests are all capable of detecting PAdV antigen." "A rise in anti-PAdV antibody in the presence of clinical disease is suggestive of clinical disease."
How this level was decided
Diarrhoea in a one-to-four-week-old pig points at half the enteric chapter before it points here, so level 1 is out. But confirmation is genuinely routine laboratory work: the virus grows readily in the standard porcine cell lines with a characteristic grape-like cytopathic effect, and PCR is available. Level 2. The reagent shortage the chapter notes applies to serotyping, which is an epidemiological refinement rather than the diagnosis. Level 2 confirmed. Easily cultured with several antigen methods available -- ordinary diagnostic laboratory work. The real difficulty the factsheet names is attribution, not detection: because the virus is routinely present in normal pigs, a positive needs a rising titre alongside disease to mean anything, which C4 does not measure.
C5 Production cost
Financial impact on the infected farm's cost of production
Negligible: No measurable effect on cost of production
Basis. ch41 41.1.1: PAdV infections "generally manifest as subclinical to mild, exhibiting low to moderate pathogenicity and rarely causing diseases of economic consequence in swine herds". 41.1.3: "In addition to diarrhea, pigs may present with mild dehydration, anorexia, and reduced weight gain, but mortalities are rare." shic_padv: "PAdV generally causes subclinical infections." "The virus rarely causes death." "PAdV is not thought to be a major threat to the United States swine industry."
How this level was decided
The chapter answers C5 in its own words -- rarely causing diseases of economic consequence. Mild, mostly subclinical, mortality rare. Under the standing note SCORING/production_cost_impact this is scored on modern US production, where it does not register as a cost. Level 1. Level 1 confirmed by direct statement.
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, diagnosis would not be expected to have any market effect"
Basis. Section 41.1 records no trade measure, movement control, export restriction or consumer response. PAdV is non-zoonotic, non-reportable, and seroprevalence in adult swine runs to 60%. shic_padv: "PAdV is not thought to be a major threat to the United States swine industry."
How this level was decided
INFERRED. Under the standing note SCORING/market_impact this is an agent long present and routinely detected in US pigs with no historical market response. Level 1. Level 1 confirmed.
C7 Treatment potential
Potential for treatment to improve outcomes
Little: Effective pathogen-directed treatment is available and works, or animals recover acceptably without it
Basis. ch41 41.1.5: control rests on "good biosecurity and sanitation to reduce environmental fecal contamination". No antiviral is described. 41.1.1: infections are "subclinical to mild"; 41.1.3: "mortalities are rare". shic_padv: "There is no treatment for PAdV infection."
How this level was decided
No pathogen-directed treatment exists, but the second clause of level 1 holds: the illness is mild and self-limiting and pigs recover without one. Little room for a treatment to improve outcomes. Level 1 held -- no product, but subclinical infection means nothing needs treating, which is the operative 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
Basis. ch41 41.1.5 states it outright: "Due to the mild nature of PAdV infections, there is little incentive to produce vaccines." shic_padv: "There is no vaccine for PAdV." "Most adult swine are seropositive to adenovirus and antibodies are presumably protective."
How this level was decided
Level 1 on the second clause of the reworded criterion, and this is the cleanest example in the register of what that clause is for. No vaccine exists, and the chapter names the reason as absence of need rather than difficulty. Under the old wording this would have been level 3 and would have scored a mild, self-limiting enteritis at maximum vaccine concern. Level 1 confirmed on the first route in the standing note -- low clinical significance, no imperative -- and with an affirmative reason attached: natural infection is near-universal and presumed protective, so a vaccine would add little.
Levels and evidence are generated from data/assignments/porcine_adenoviruses.yml; the overview is authored in data/overviews/porcine_adenoviruses.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.