Escherichia coli (neonatal colibacillosis)
LEVELS: Highly unlikely; No human illness; Already in the herd; Routine; Minor; Negligible; Little; Available, or not needed
| Register id | ecoli_neonatal_colibacillosis |
| Type | bacteria |
| Scientific name | Escherichia coli |
| NCBI taxid | 562 |
| Evidence | 2 document(s) |
| Assigned | 2026-09-04, against criteria version 093366e352a2 |
Overview
Neonatal colibacillosis is diarrhoea of the newborn piglet caused by enterotoxigenic Escherichia coli — strains carrying fimbriae, chiefly F4 and F5, that let them stick to the lining of the small intestine, where they release toxins that drive fluid out of the pig. Scouring can begin within hours of birth and may affect a single piglet or a whole litter. On average 30–40% of pigs in an affected herd are involved, occasionally up to 80%, and in litters under four days old mortality can reach 70%; older piglets fare much better. Death is from dehydration, so piglets that keep drinking and are treated promptly usually recover. The organisms are not exotic — the same ETEC strains are shed by perfectly healthy pigs — so this is a disease of dose, hygiene and passive immunity rather than of introduction, and routine cleaning and disinfection alone rarely break the cycle. It is one of the most costly diseases of the farrowing house, estimated at around $53 per sow at 10% mortality. The pathotype that causes it is not the one that causes human disease.
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. ch49 49.3, the whole public health section for the chapter, and it is about ONE pathotype: "A STEC subgroup known as EHEC, particularly EHEC O157:H7, O26, and other non-O157 serogroups, may be sporadically present in the intestines and feces of pigs and are known to cause bloody diarrhea, hemorrhagic colitis, and hemolytic uremic syndrome in humans infected through food or water contaminated by animal feces. PIGS ARE NOT CONSIDERED A MAJOR SOURCE OF O157 EHEC, AS THE PREVALENCE RATE IS TYPICALLY VERY LOW." Surveys of healthy slaughter pigs bear that out: Alberta 1.4% of pigs and 1.8% of carcasses, Japan 1.4%, Ireland 0.21-0.63%, United Kingdom 0.3%, Sweden 0.08%, Norway 0.1%, United States 2%. The remainder of 49.3 is about antimicrobial resistance rather than about infection.
How this level was decided
Level 1, on a structured silence this chapter makes unusually legible. It gives the human question its own section and uses that section to discuss exactly one pathotype, EHEC -- and this entry is not EHEC. Neonatal colibacillosis is caused by ETEC carrying the F4, F5, F6 and F41 fimbriae, which are porcine colonisation factors: they attach to receptors on pig enterocytes, and human ETEC uses an entirely different set. The chapter never suggests that porcine ETEC infects people. NOTE, AND IT IS A GAP IN THE FRAMEWORK RATHER THAN IN THIS ENTRY: half of the chapter's public health section is antimicrobial resistance -- the mcr-1 plasmid-mediated colistin resistance gene, third and fourth generation cephalosporins, fluoroquinolones, and the observation that pigs carry a greater diversity of mcr variants than other hosts. That is the largest public health story attached to E. coli in pigs and THE 8-CRITERION FRAMEWORK SCORES IT NOWHERE. C1 measures transmission of the agent, not horizontal transfer of a resistance gene, and the AMR criterion that existed in the 10-criterion framework was removed in August 2026 -- Karriker voted to drop it and three of seven reviewers agreed. Recorded here on all four E. coli entries so the absence is visible rather than silent.
C2 Zoonotic impact
Severity of human illness caused by the agent
No human illness: Agent does not cause illness in people
Basis. ch49 49.3, the whole public health section for the chapter, and it is about ONE pathotype: "A STEC subgroup known as EHEC, particularly EHEC O157:H7, O26, and other non-O157 serogroups, may be sporadically present in the intestines and feces of pigs and are known to cause bloody diarrhea, hemorrhagic colitis, and hemolytic uremic syndrome in humans infected through food or water contaminated by animal feces. PIGS ARE NOT CONSIDERED A MAJOR SOURCE OF O157 EHEC, AS THE PREVALENCE RATE IS TYPICALLY VERY LOW." Surveys of healthy slaughter pigs bear that out: Alberta 1.4% of pigs and 1.8% of carcasses, Japan 1.4%, Ireland 0.21-0.63%, United Kingdom 0.3%, Sweden 0.08%, Norway 0.1%, United States 2%. The remainder of 49.3 is about antimicrobial resistance rather than about infection.
How this level was decided
Level 1. C2 grades illness acquired from pigs, and no human illness is attributable to porcine ETEC. THE LABEL MUST NOT BE READ AS "E. COLI IS HARMLESS TO PEOPLE" -- the chapter describes EHEC causing haemorrhagic colitis and haemolytic uraemic syndrome in the same section. It records that this pathotype, the one that causes neonatal scours in piglets, is not the one that does that.
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. ch49 49.4.1: "The primary habitat of E. coli in the pig is the gastrointestinal tract, which is colonized after birth by environmental and maternal bacteria." "Interestingly, ETEC can be shed in the feces of healthy pigs as part of the intestinal microbiota. Moredo et al. (2015) demonstrated that the percentage of ETEC-positive non-diarrheic pigs was 16.6% during the lactation period, 66% in the nursery phase, and 17.3% in the finisher population." 49.4.5: "Routine cleaning and disinfection are usually insufficient to break the cycle of infection with E. coli."
How this level was decided
Level 1, the framework's worked example at that level, and the chapter measures it: two thirds of healthy nursery pigs are already carrying the pathogenic type. E. coli colonises the piglet gut within hours of birth from the sow and the environment, and the pathogenic strains are a subset of what is already there. There is no introduction event to prevent. NOTE that the chapter still recommends stringent biosecurity, but for a narrower reason -- to control the introduction of DIFFERENT virotypes against which the herd has no immunity, not to keep E. coli out.
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
Basis. ch49 49.5.2.1: "Neonatal diarrhea may first be observed 2-3 hours after birth and may affect individual pigs or whole litters... Diarrhea may be very mild with no evidence of dehydration or may be clear, watery, and profuse with a distinctive smell and alkaline pH." 49.5.4.2: "The presence of a significant number of hemolytic colonies is often used as a rapid means for confirming a presumptive diagnosis of enteric colibacillosis or ED." Faeces or rectal swabs are plated on MacConkey, Hektoen or Gassner agar and blood agar overnight, and "Primers recognizing genes encoding for toxins (STa, STb, LT, Stx2e, and EAST1) and fimbriae (F4, F5, F6, F18, and F41) of ETEC are available for virotyping and can be used to perform PCR assays for routine diagnostics on isolated bacterial colonies."
How this level was decided
Level 1, the framework's worked example, and both halves hold. Watery scour in a whole litter within days of birth is recognised in normal practice, and confirmation is overnight culture on ordinary selective media with haemolysis read as a rapid presumptive marker, followed by PCR virotyping that any regional laboratory runs. NOTE the interpretive rule the chapter insists on, which is a limit on reading the result rather than on getting one: pathogenic E. coli is also isolated from healthy pigs, so the diagnosis needs SEMIQUANTITATIVE bacteriology -- pure or nearly pure culture, or at least 70% of colonies, from the jejunum and ileum.
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
Basis. ch49 49.1: "The estimated cost of neonatal diarrhea with 10% mortality and low-grade PWD has been reported as $53 and $179 per sow, respectively." 49.5.2.1: "Morbidity in an affected herd is extremely variable. The average is 30-40% but may be as high as 80% in some herds. Mortality is higher in pigs less than 4 days old and can reach 70% in affected litters. In pigs older than 7 days, morbidity and mortality are much lower." "Pigs with less severe dehydration may continue to drink and, if treated appropriately, recover with only minimal long-term effects."
How this level was decided
Level 2, the framework's worked example, and the chapter gives the number the criterion wants: $53 per sow per year at 10% mortality. The litter-level figures look worse -- up to 70% mortality in an affected litter -- but they apply to a minority of litters, mostly from first-parity sows without passive immunity, and recovered pigs carry minimal long-term effect. Small and generally short-lived losses. It is the disease every farrowing house manages continuously rather than one that changes the economics.
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
Basis. ch49 49.4.2: "Escherichia coli infections are widespread, occurring in both industrialized and developing countries and in temperate, subtropical, and tropical climates." 49.1: neonatal diarrhoea has "been recognized as important diseases of pigs for over 50 years". No trade measure, movement control or consumer response is recorded anywhere in the chapter.
How this level was decided
Level 1, the framework's worked example, and the longest observed precedent available: a disease of every pig-producing country for over fifty years, diagnosed continuously in US herds, with no market move ever recorded. Under the standing note SCORING/market_impact that is the endemic case in its purest form.
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, agree with assessment"
Basis. ch49 49.5.6.1: "Treatment with antimicrobials at the earliest sign of diarrhea in neonatal and postweaning colibacillosis may be administered on an individual or litter basis and by mouth or parenteral injection." Fluid therapy with electrolyte replacement treats the dehydration and acidosis. Against that: "The development of bacterial resistance against a wide range of antimicrobial drugs makes this choice, and consequently the efficacy of antimicrobial therapeutics, uncertain."
How this level was decided
Level 1, the framework's worked example. Labelled antimicrobials for E. coli scours are available and used in the US, they work when the isolate is susceptible, and supportive fluid therapy addresses what actually kills the pig. FLAGGED, because the chapter's own caveat pulls toward level 2 and the same caveat sits on the postweaning entry: resistance across a wide range of drugs makes the empirical first choice uncertain, and the chapter says susceptibility testing is indispensable for managing the therapy. Scored level 1 on the framework rather than judged here.
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. ch49 49.5.6.3: "Maternal vaccination has been one of the most effective ways of preventing neonatal ETEC diarrhea in piglets." "There are currently a number of commercially available vaccines, based on killed whole-cell bacterins or purified fimbrial antigens, that can be given parenterally... Bacterins usually contain strains representing the most important serogroups and producing the fimbrial antigens F4, F5, F6, and F41. Most vaccines contain antigens for other pathogens as well, such as C. perfringens and rotavirus."
How this level was decided
Level 1, the framework's worked example, and it reads on the first clause without strain. Commercial sow vaccines are widely available in the US, cover the four fimbrial types that cause the disease, are commonly combined with clostridial and rotavirus antigens in one product, and the chapter calls maternal vaccination one of the most effective preventives there is. NOTE the known failure mode, which is a limitation rather than a level change: the vaccines are given parenterally and depend on the sow having met ETEC mucosally before, which is why litters of vaccinated GILTS still break.
Levels and evidence are generated from data/assignments/ecoli_neonatal_colibacillosis.yml; the overview is authored in data/overviews/ecoli_neonatal_colibacillosis.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.