Bordetella bronchiseptica

LEVELS: Highly unlikely; Moderate; Already in the herd; Laboratory-dependent; Minor; Negligible; Some; Available but inconsistent


Register id	`bordetella_bronchiseptica`
Type	bacteria
Scientific name	Bordetella bronchiseptica
NCBI taxid	518
Evidence	1 document(s)
Assigned	2026-09-04, against criteria version `093366e352a2`

Overview

Bordetella bronchiseptica is a gram-negative bacterium found in pig herds almost everywhere, and it is routinely isolated from healthy animals as well as sick ones. Piglets usually pick it up from the sow before weaning. On its own it causes non-progressive atrophic rhinitis, a mild and reversible turbinate damage, and in young pigs it can cause a serious necrotising bronchopneumonia in its own right. Its greater importance is indirect: by colonising the nose first it opens the way for toxigenic strains of Pasteurella multocida, and that combination produces progressive atrophic rhinitis, the severe and permanent form — which is scored separately on this register. Maternal antibody protects piglets against the lesions but not against becoming infected, so the organism persists in a herd regardless. Because it is so common, control is aimed at limiting damage rather than at keeping it out.

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. REVIEWED ON C1_C2_RECLASSIFICATION.md, 2026-09-04, after the C1/C2 rewording that separated exposure from consequence. Eric marked up every moved cell and reversed his own earlier setting on twenty of the twenty-one: "In almost every case, I agreed with new opinion and reversed my old setting." HIS MARKUP HERE WAS "L1". He had ruled level 2 on 2026-09-03 under the old label, where "never reported from pigs" still belonged in level 2. It now belongs in level 1, and ch44 44.3 says no human cases related to transmission from swine have been reported -- the presumed source in most human cases is dogs, cats and rabbits.

Basis. SCOPE OF THE ENTRY: B. bronchiseptica causes NONPROGRESSIVE atrophic rhinitis in its own right and ENABLES progressive atrophic rhinitis by opening the way for toxigenic P. multocida. PAR is a separate register entry, already assessed, and its cost is scored there. Counting the PAR losses here as well would double them, and PAPRIKA ADDS THE CRITERIA, so the extra weight would be invisible. ch44 44.3, a Public Health section that states the answer and its limit in consecutive sentences: "HUMAN ILLNESS RESULTING FROM B. BRONCHISEPTICA INFECTION IS RARE BUT ON THE RISE. Most at risk are infants and immunocompromised individuals with exposure to carrier animals; however, disease in immunocompetent adults also occurs... IN MANY CASES, EXPOSURE TO DOMESTICATED PETS, PARTICULARLY DOGS, CATS, AND RABBITS, IS THE PRESUMED SOURCE OF INFECTION. NO HUMAN CASES RELATED TO TRANSMISSION FROM SWINE HAVE BEEN REPORTED. However, ONE OF THE FEW ANIMAL ISOLATES AMONG THE HUMAN-DOMINATED COMPLEX IV B. BRONCHISEPTICA STRAINS IS OF SWINE ORIGIN (Diavatopoulos et al. 2005). WHETHER SWINE CAN ACT AS A RESERVOIR AND TRANSMIT B. BRONCHISEPTICA TO HUMANS OR VICE VERSA IS PLAUSIBLE BUT CURRENTLY UNKNOWN."

How this level was decided

MOVED L2 -> L1, re-read 2026-09-04 AGAINST THE REWORDED LABELS. ch44 44.3 states it: human illness is real and rising, but "IN MANY CASES, EXPOSURE TO DOMESTICATED PETS, PARTICULARLY DOGS, CATS, AND RABBITS, IS THE PRESUMED SOURCE" and "NO HUMAN CASES RELATED TO TRANSMISSION FROM SWINE HAVE" been reported. Reported in people, not attributed to pigs.

PREVIOUS ANSWER, kept because the evidence behind it has not changed, only the level boundary: Level 2, FLAGGED, and it is put to you because you have ruled four cells of this shape today and I want the fifth to match rather than drift. THE LEVEL 2 LABEL IS "human infection from pigs is PLAUSIBLE BUT HAS NEVER (OR RARELY) BEEN REPORTED, and specific control points are not commonly implemented", and the chapter uses both of those words: never reported from swine, and plausible. That is an unusually exact fit. THE ARGUMENT FOR LEVEL 1 is your Staphylococcus hyicus ruling from this evening -- "though isolated from humans rarely IT IS MISLEADING TO CONSIDER IT A CONSEQUENTIAL ZOONOSIS" -- and it is arguably stronger here than there, because S. hyicus at least had three human case reports and this has zero from pigs, with pets named as the usual source. WHAT HOLDS IT AT 2 RATHER THAN 1 is the single swine-origin isolate sitting inside the human-adapted complex IV lineage, which is a thread and not nothing. If you read that as the literature overrating the potential, take it to 1 and C2 goes with it.

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

CONFIRMED by Eric. The assignment reached this level from the evidence, and he has reviewed and ratified it.

Confirmed by Eric. CONFIRMED. "c2l3, again hard to understand to what extent pig strains are involved in human cases but the evidence is convincing that the agent can cause moderate diseaes in people"

How this level was decided

INFERRED, AND IT MOVES WITH C1. Level 3 -- clinically important illness that may require medical treatment or hospitalization, with death or permanent disability uncommon. Whooping cough, pneumonia and meningitis are hospital admissions; "occasionally with a fatal outcome" is the level 3 rather than the level 4 phrasing, since level 4 asks for a SUBSTANTIAL risk of death or permanent disability. IF YOU RULE C1 TO LEVEL 1, THIS CELL MUST GO TO LEVEL 1 WITH IT -- C1 level 1 implies C2 level 1 and validate_criteria.py enforces it per entry.

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

How this level was decided

Level 1, AND THIS IS YOUR OWN RULING APPLIED. Deciding progressive atrophic rhinitis you wrote: "B.BORD IS PROBABLY NOT EXCLUDABLE FROM HERDS, both toxigenic P.mult is excludable", and again on 2026-08-28 that PAR "stays at c3l2 due more to the importance/requirement for P.mult toxigenic strain rather than B.bord". The chapter agrees: highly prevalent, carried by apparently healthy pigs, acquired from the sow before weaning, and persisting in the nose indefinitely, with even maternal antibody failing to prevent infection. There is no introduction event to prevent. NOTE HOW THIS SITS BESIDE PAR AT LEVEL 3 WITHOUT CONTRADICTING IT: PAR needs a second organism that CAN be excluded, and that is what its higher level is scoring.

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. SCOPE OF THE ENTRY: B. bronchiseptica causes NONPROGRESSIVE atrophic rhinitis in its own right and ENABLES progressive atrophic rhinitis by opening the way for toxigenic P. multocida. PAR is a separate register entry, already assessed, and its cost is scored there. Counting the PAR losses here as well would double them, and PAPRIKA ADDS THE CRITERIA, so the extra weight would be invisible. ch44 44.8: "MANY PATHOGENS OTHER THAN B. BRONCHISEPTICA OFTEN CAUSE PNEUMONIA IN PIGS... this organism MOST COMMONLY OCCURS IN MIXED INFECTIONS and is frequently found together with one or more other respiratory disease agents. IN SUCH CASES, THE ACTUAL CONTRIBUTION OF B. BRONCHISEPTICA TO CLINICAL DISEASE MAY BE DIFFICULT TO DETERMINE. Acute lung lesions in piglets can appear very similar to those caused by Actinobacillus suis or Actinobacillus pleuropneumoniae." On confirmation: "B. BRONCHISEPTICA GROWS READILY ON BLOOD AGAR; however, THE USE OF A SELECTIVE MEDIUM IS DESIRABLE to prevent overgrowth... MATRIX-ASSISTED LASER DESORPTION IONIZATION/TIME-OF-FLIGHT (MALDI-TOF) MASS SPECTROMETRY IS CAPABLE OF IDENTIFYING BORDETELLA TO THE SPECIES LEVEL AND IS WIDELY USED IN DIAGNOSTIC LABORATORIES... polymerase chain reaction (PCR) [is] SENSITIVE AND SPECIFIC for B. bronchiseptica."

How this level was decided

Level 2. Nothing about the presentation names this organism -- it is usually one of several in a mixed respiratory infection and its contribution is hard to apportion -- so it is not level 1; and identification is culture on selective medium with MALDI-TOF, which the chapter says is widely used in diagnostic laboratories, or a specific PCR. That is a validated assay at local or regional level, which is the level 2 label. Serology exists but "is rarely used routinely for diagnostic purposes".

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, minor contributor to clinical disease in pigs"

Basis. SCOPE OF THE ENTRY: B. bronchiseptica causes NONPROGRESSIVE atrophic rhinitis in its own right and ENABLES progressive atrophic rhinitis by opening the way for toxigenic P. multocida. PAR is a separate register entry, already assessed, and its cost is scored there. Counting the PAR losses here as well would double them, and PAPRIKA ADDS THE CRITERIA, so the extra weight would be invisible. ch44 44.1: "It is the primary etiologic agent of NONPROGRESSIVE ATROPHIC RHINITIS (NPAR), A MILD-TO-MODERATELY SEVERE, REVERSIBLE CONDITION. More importantly, nasal colonization by B. bronchiseptica promotes colonization by toxigenic strains of Pasteurella multocida, WHICH LEADS TO SEVERE, PROGRESSIVE ATROPHIC RHINITIS (PAR; see Chapter 54). IN YOUNG PIGS, B. BRONCHISEPTICA IS A PRIMARY CAUSE OF NECROHEMORRHAGIC BRONCHOPNEUMONIA, and in older pigs, it can be an opportunistic pathogen contributing to the porcine respiratory disease complex (PRDC). B. bronchiseptica can also ENHANCE RESPIRATORY COLONIZATION OF STREPTOCOCCUS SUIS AND GLAESSERELLA PARASUIS, promote disease caused by S. suis, and it can INTERACT WITH PRRSV AND INFLUENZA A VIRUS to increase the severity of respiratory disease." ch54 54.1 confirms NPAR is "accompanied by MINOR EFFECTS ON GROWTH."

How this level was decided

INFERRED. Level 2 -- small and generally short-lived losses. THE SCORING PROBLEM HERE IS ATTRIBUTION RATHER THAN MAGNITUDE, and it is why this cell is inferred. What this organism does IN ITS OWN RIGHT is nonprogressive atrophic rhinitis, which both chapters call mild, reversible and minor in its growth effect, plus necrohaemorrhagic bronchopneumonia in young pigs, which is serious but not the general case. WHAT IT MOSTLY DOES IS MAKE OTHER AGENTS WORSE -- it opens the way for toxigenic P. multocida and PAR, enhances Streptococcus suis and Glaesserella parasuis, and worsens PRRSV and influenza. Those costs are already carried by the entries for those agents, and PAR at C5 level 3 is one of them. Adding them here would double-count into an additive model. THE ARGUMENT FOR LEVEL 3 is that its enabling role IS its economic significance and a register that scores only its own disease understates it; that is a real objection to how the framework handles enablers, and it has no home in any of the eight criteria.

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, old agent, no impact on markets"

How this level was decided

INFERRED. Level 1 under the standing note SCORING/market_impact: an organism long endemic and routinely diagnosed in US pigs with no market move ever observed. Scored the same as progressive atrophic rhinitis, which you confirmed at 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. SCOPE OF THE ENTRY: B. bronchiseptica causes NONPROGRESSIVE atrophic rhinitis in its own right and ENABLES progressive atrophic rhinitis by opening the way for toxigenic P. multocida. PAR is a separate register entry, already assessed, and its cost is scored there. Counting the PAR losses here as well would double them, and PAPRIKA ADDS THE CRITERIA, so the extra weight would be invisible. ch44 44.10: "ANTIBIOTICS LABELED FOR THE TREATMENT OF SWINE RESPIRATORY DISEASE, AND SPECIFICALLY B. BRONCHISEPTICA, INCLUDE ENROFLOXACIN, FLORFENICOL, AND TULATHROMYCIN. VARIABLE RESISTANCE HAS BEEN REPORTED TO FLORFENICOL." And the failures: "BORDETELLA IS LARGELY RESISTANT TO BETA-LACTAM ANTIBIOTICS, INCLUDING AMPICILLIN AND CEPHALOSPORINS SUCH AS CEFTIOFUR... ACCORDINGLY, CEFTIOFUR IS NOT THE OPTIMAL CHOICE when treating mixed infections that include B. bronchiseptica as a component. Of the other antibiotics commonly used for respiratory disease in swine, TYLOSIN AND TIAMULIN ARE INEFFECTIVE against B. bronchiseptica, and SIGNIFICANT RESISTANCE TO TILMICOSIN has been reported... TOTAL CLEARANCE OF BORDETELLA FROM THE UPPER RESPIRATORY TRACT IS DIFFICULT." Two controlled results: oxytetracycline "WAS NOT CLEARED from the nasal cavity, trachea, or lung after 7 days, and THERE WAS NO DIFFERENCE IN COLONIZATION LEVELS between treated and non-treated animals, although lung lesions were less extensive"; gamithromycin "reduced clinical and lesion scores... BUT NASAL AND TRACHEAL COLONIZATION WAS ONLY MILDLY REDUCED."

How this level was decided

Level 2, and this entry is a clean illustration of your rule that a labelled product does not force level 1. THE LABEL TEST IS SATISFIED IN TERMS -- the chapter says enrofloxacin, florfenicol and tulathromycin are labelled specifically for B. bronchiseptica -- and the level is still 2, because the level 2 clause "works only in some circumstances" is met three ways: several of the drugs a practitioner would reach for first are useless against it (beta-lactams, ceftiofur, tylosin, tiamulin), resistance to florfenicol and tilmicosin is reported, and the two controlled trials quoted reduced lesions without clearing the organism. Treatment improves the pig and leaves the herd infected.

C8 Vaccine availability

Availability of effective vaccines or bacterins

Available but inconsistent: Commercial or autogenous vaccines exist in the US but protection may be inconsistent

Basis. SCOPE OF THE ENTRY: B. bronchiseptica causes NONPROGRESSIVE atrophic rhinitis in its own right and ENABLES progressive atrophic rhinitis by opening the way for toxigenic P. multocida. PAR is a separate register entry, already assessed, and its cost is scored there. Counting the PAR losses here as well would double them, and PAPRIKA ADDS THE CRITERIA, so the extra weight would be invisible. ch44 44.10: "VACCINES FOR B. BRONCHISEPTICA LARGELY CONSIST OF WHOLE-CELL BACTERINS, OFTEN IN COMBINATION WITH P. MULTOCIDA WHOLE-CELL BACTERINS OR TOXOIDS FOR CONTROL OF ATROPHIC RHINITIS, BUT THERE ARE A FEW ATTENUATED INTRANASAL VACCINES AVAILABLE AS WELL... VACCINATION OF SOWS AROUND 6 WEEKS AND AGAIN AROUND 2 WEEKS PRIOR TO FARROWING APPEARS TO WORK WELL." 44.4 on what that protection is worth: "ANTIBODY PASSIVELY ACQUIRED BY PIGLETS FROM THE COLOSTRUM OF INFECTED OR VACCINATED SOWS PROTECTS AGAINST TURBINATE LESIONS AND PNEUMONIA BUT NOT AGAINST INFECTION. However, VACCINATION OF SOWS MAY DELAY INFECTION FOR UP TO SEVERAL WEEKS, at which time lesions typically fail to develop or are significantly reduced in severity."

How this level was decided

Level 2. Commercial bacterins and attenuated intranasal products are available in the US and the sow programme is described as working well, so this is not level 3; and the disease warrants vaccinating, so it is not the "not needed" half of level 1. What holds it at level 2 is the chapter's own qualification: protection is against LESIONS AND PNEUMONIA BUT NOT AGAINST INFECTION, and the mechanism is delay rather than prevention -- the piglet is colonised later, when the turbinates are past the age at which they deform. That is available but inconsistent, and it is the same shape as the Glaesserella and Actinobacillus bacterins in this batch.

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