Actinobaculum suis
LEVELS: Highly unlikely; No human illness; Already in the herd; Routine; Minor; Negligible; Some; Available, or not needed
| Register id | actinobaculum_suis |
| Type | bacteria |
| Scientific name | Actinobaculum suis |
| NCBI taxid | 1657 |
| Evidence | 1 document(s) |
| Assigned | 2026-09-04, against criteria version 093366e352a2 |
Overview
Actinobaculum suis is a bacterium that causes cystitis and pyelonephritis — bladder and kidney infection — in sows. Boars are the reservoir: almost all males over six months of age carry it in the preputial diverticulum, without any sign of disease themselves, and pass it to sows at mating. It also survives on the floors of pens housing boars, so uninfected males pick it up simply by being housed with carriers. Affected sows typically show blood in the urine two to three weeks after service, and the infection can ascend from the bladder to the kidneys; sows that reach that stage frequently die of renal failure. It occurs in individuals or small groups rather than as a herd outbreak, and it is not a public health concern. Antibiotics often work but relapses are common, so culling an affected sow is usually recommended over prolonged treatment. Artificial insemination removes the route of transmission altogether.
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. "Actinobaculum suis causes cystitis and pyelonephritis in individual or small groups of sows and is carried by boars. It is not a public health concern." (ch58 58.1.1)
How this level was decided
The chapter states the position directly and in the terms C1 asks for. No human infection from pigs is described anywhere in the section, and the pig is named as the main host. Level 1.
C2 Zoonotic impact
Severity of human illness caused by the agent
No human illness: Agent does not cause illness in people
Basis. "It is not a public health concern." (ch58 58.1.1)
How this level was decided
C2 says to score level 1 whenever the agent does not cause disease in people. The section records no human illness of any kind.
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. "The pig is the main host of A. suis, and most male pigs, aged 6 months or more, harbor A. suis in the preputial diverticulum." "The organism may be found on the floors of pens occupied by male pigs, and uninfected males are readily infected when they are housed with carriers." (ch58 58.1.2)
How this level was decided
Carried by the pigs themselves, in most boars over six months of age, so there is no introduction event to prevent. That is level 1 word for word. Disease follows from mating and management, not from an incursion.
C4 Detection difficulty
Difficulty of recognizing and confirming infection
Routine: The disease would be suspected from clinical signs, history and epidemiology in normal practice, and confirmed by tests that local or regional laboratories run routinely
CONFIRMED by Eric. The assignment reached this level from the evidence, and he has reviewed and ratified it.
Confirmed by Eric. CONFIRMED. "l1, anaerobic culture should be available by request or indicated by case submission history"
Basis. "The presence of hematuria 2-3 weeks after service by a boar suggests A. suis cystitis and pyelonephritis, rather than cystitis caused by Escherichia coli." "Diagnosis is based on clinical signs and bacterial culture of urine or the urinary tract." "Anaerobic incubation for 4 days is essential for isolation from urine or affected tissue." (ch58 58.1.3)
How this level was decided
Both halves of level 1 are met: the clinical picture points to this disease specifically -- hematuria at a characteristic interval after service -- and confirmation is anaerobic culture, which regional veterinary diagnostic laboratories run. Culture is insensitive against PCR (0 vs 8.9% of sow urines), but that is a sensitivity limit of a routinely available test, not a referral requirement.
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, reason is that scale of disease is individual sows or small groups rather than a herd-level event, so the effect on overall cost of production is small"
Basis. "causes cystitis and pyelonephritis in individual or small groups of sows" "Clinically affected sows frequently die from renal failure." "Antibiotics are frequently effective, but relapses occur, and early slaughter of affected animals is recommended." (ch58 58.1.1, 58.1.3, 58.1.4)
How this level was decided
INFERRED. The chapter gives no cost figure. Sow death and forced culling are real per-animal losses, but the stated scale is individual sows or small groups rather than a herd-level event, so the effect on overall cost of production is small. Level 2. Level 3 would need losses that measurably move herd cost of production, which the folder does not support.
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. "ctl1, reason is that this is a common, endemic agent with small footprint of disease with no potential for multi-herd outbreaks that would effect pig movements or markets". He wrote "ctl1"; the harvester refused to read a level from it. He confirmed the reading on 2026-08-28: "yes A.suis".
Basis. The section describes a sporadic, non-zoonotic urinary tract disease of individual sows and boars. It says nothing about markets, movement controls, trade or consumer response.
How this level was decided
INFERRED. A non-zoonotic sporadic disease of individual breeding females has no route to supply or demand for pork or live pigs -- no trade measure, no movement control, no consumer dimension. Level 1.
C7 Treatment potential
Potential for treatment to improve outcomes
Some: Treatment exists but is inconsistent, requires extralabel use, or works only in some circumstances
Basis. "Actinobaculum suis is sensitive in vitro to several antibiotics, including penicillin and tetracyclines, although more recent work from Brazil has observed elevated MICs to tetracyclines, macrolides, and fluoroquinolones." "Antibiotics are frequently effective, but relapses occur, and early slaughter of affected animals is recommended. Prolonged treatment for 20 days with ampicillin given at 20 mg/kg has been suggested." (ch58 58.1.4)
How this level was decided
Treatment exists and often works, but the chapter qualifies it twice -- relapses occur, and a 20-day course is required -- and recommends early slaughter regardless. Rising MICs to three drug classes are recorded. That is level 2, treatment that exists but is inconsistent, not level 1.
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 AT LEVEL 1. "c8l3 is correct, though this places it at the high risk end of scale, that is the reality. Ground truth however is that the disease has so little impact and low prevalence that vaccination, even if available, would be unlikely to produce a positive return" Eric, 2026-08-28: "all seven to L1". Re-ruled after the C8 rewording of the same day. His 2026-08-27 words are unchanged and are quoted above in full -- what has moved is the level they map to. He wrote each of them to say that no vaccine is NEEDED here, and level 3 was then the only place a missing vaccine could go, so the reasoning and the level contradicted each other. The reworded level 1 holds exactly what he was describing: no vaccine exists, and the disease does not justify one. Recorded as a confirmation of the reworded pass rather than an override, because the pass now agrees with him.
Basis. ch58 58.1.4 names antimicrobials, euthanasia of non-responders and artificial insemination, and no vaccine. Eric, 2026-08-27: "the disease has so little impact and low prevalence that vaccination, even if available, would be unlikely to produce a positive return".
How this level was decided
MOVED L3 -> L1 by the 2026-08-28 rewording, not by new evidence. No vaccine exists, which was the whole of the old level 3. The reworded level 3 also requires that the disease would justify one, and Eric ruled in terms that it does not. Sporadic cystitis in individual sows, at low prevalence, with a negative return on vaccination even if a product existed. Level 1 second clause.
Levels and evidence are generated from data/assignments/actinobaculum_suis.yml; the overview is authored in data/overviews/actinobaculum_suis.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.