Vibriosis (Non-cholera Vibrio)

• Reporting criteria
• The disease and its epidemiology
• Case definition

• Laboratory testing
• Case investigation
• Disease control measures

• References
• Contact

What and how to report to the Colorado Department of Public Health and Environment (CDPHE) or local public health agency  

• All specimens with a positive test for a species of the family Vibrionaceae (regardless of specimen source; except toxigenic V. cholerae O1 or O139 — see below) by culture, enzyme immunoassays (EIA), polymerase chain reaction (PCR), or other form of testing should be reported to public health within four (4) days of the positive test result. 
• All positive Vibrio laboratory tests should be reported to public health, regardless of symptoms. Public health will make the determination of whether the case meets the case definition.
• Genera in the family Vibrionaceae (not all have been recognized to cause human illness) currently include:
  • Aliivibrio
  • Allomonas
  • Catenococcus
  • Enterovibrio
  • Grimontia
  • Listonella
  • Photobacterium
  • Salinivibrio
  • Vibrio
• Toxigenic V. cholerae O1 or O139 are reportable as cholera, regardless of specimen source. Suspected toxigenic V. cholerae (cholera) infections are 24-hour reportable conditions and public health should be notified to begin investigations quickly.
  • For additional information regarding suspected cholera cases, contact CDPHE.
• Cases should be reported using EpiTrax Reportal, fax, or telephone to CDPHE or local health departments (telephone and fax numbers are listed at the end of this document).
• All potential foodborne, waterborne, and enteric disease outbreaks should be reported immediately to CDPHE or local health departments and entered into EpiTrax, even if the causative agent is not yet known.
  • In general, an “outbreak” is defined as an increase in the number of illnesses above what is normally expected among a specific population, within a given area, over a certain period of time. 
  • Specifically, a foodborne disease outbreak occurs when two or more people get the same illness from the same contaminated food or drink.

Purpose of surveillance and reporting

• To identify cases for investigation and potential outbreaks
• To monitor trends in disease incidence

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Etiologic agent

Non-cholera Vibrio infections (referred hereafter as Vibrio infections) are caused by bacteria in the genus Vibrio. There are more than 20 Vibrio species which can cause vibriosis in humans. The most common reported species in Colorado is Vibrio parahaemolyticus, often due to contaminated seafood. The most severe form seen in Colorado and nationally is Vibrio vulnificus. This chapter does not address cholera (infection caused by toxigenic Vibrio cholerae serogroup O1 or O139). If a cholera case is suspected, contact CDPHE for assistance.

Clinical description

Vibrio infections can result in diarrhea, wound infection, or septicemia. Asymptomatic infections, albeit rare, may occur. Infection with Vibrio species usually results in a diarrheal illness. Symptoms can include watery diarrhea, abdominal cramps, nausea, vomiting, fever, headache, and chills. Various Vibrio species can also cause wound infections, and less often septicemia, as well as ear infections. 

Vibrio vulnificus infections generally result in septicemia or severe wound infections which can be life-threatening. The case fatality rate among persons with septicemia is approximately 40%. Some wound infections may cause necrotizing fasciitis, a severe infection in which the flesh around an open wound dies and may require limb amputation.

Persons with liver disease, cancer, decreased gastric acidity, diabetes, peptic ulcers, immunosuppression, iron storage disorders, malignancies, alcoholism, or who have had recent stomach surgery are at higher risk of acquiring illness and developing more severe illness.

Reservoirs

Vibrio species naturally live in marine coastal environments or in brackish water. Most species are halophilic (salt tolerant). Most Vibrio species that cause illness are not found naturally in Colorado, however, ample opportunity exists for Colorado residents to be exposed to Vibrio spp. during travel to coastal areas or when consuming raw or undercooked seafood such as oysters, crab or shrimp. The presence of Vibrio spp. in water is not a sign of pollution. The amount of Vibrio spp. in water is directly related to the water temperature, increasing with rising water temperatures.

Modes of transmission

Vibrio can be transmitted through ingestion or contact with non-intact skin. Vibrio enteritis (inflammation of the small intestine) is usually a result of ingesting the organism in raw or undercooked seafood, especially shellfish (such as oysters, crab, or shrimp). Wound infections can occur when a person with a wound has contact with seawater or a person sustains cuts while handling raw shellfish. Septicemia (blood poisoning) can occur through either ingesting raw or undercooked seafood or through seawater contact with a wound.

Incubation period

The incubation period for Vibrio infections is species-dependent. For V. parahaemolyticus, the usual period is 12–24 hours with a range of about 4–30 hours. The incubation period for V. vulnificus is usually 12 hours to 3 days.

Infectious period

Non-cholera Vibrio infections are not known to spread from one person to another. 

Epidemiology

Vibrio species are endemic to coastal areas where they thrive in brackish water environments. Due to the landlocked geography of Colorado, most Vibrio infections reported in the state are acquired as a result of consuming raw or undercooked seafood or travel to coastal areas.

Vibrio infections are reported throughout the year in Colorado, however, reported cases peak in the summer months, presumably because of warmer water temperatures. During 2023, 88 cases were reported in Colorado, with a five-year average of 67 cases per year (2019-2023). 

In 2022, there were 2,654 Vibrio cases reported in the United States, with a five-year average of 2,559 cases per year (2018-2022). Thirty two percent of cases were hospitalized, and 3% of cases died. Four percent of cases were associated with outbreaks. During their exposure period, 67% of patients report eating seafood, and of these, 60% reported undercooked or raw seafood consumption. 

In the United States, V. parahaemolyticus remains the most commonly detected Vibrio species, accounting for 36% of culture-confirmed cases. Other common culture confirmed species in the United States include V. alginolyticus (18%), V. vulnificus (12%), V. cholerae (10%), and V. fluvialis (7%).

In the United States, outbreaks of vibriosis have been attributed to imported oysters, imported fresh crab meat, and raw, domestic shellfish.

For more data, see Colorado reportable disease data (Colorado data), CDC WONDER and CDC BEAM Dashboard (national data), and CDC FoodNet Fast (FoodNet catchment area data).

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Clinical criteria

An infection of variable severity characterized by watery diarrhea, primary septicemia, or wound infection. Asymptomatic infections may occur, and the organism may cause extra-intestinal infection.

Laboratory criteria for diagnosis

Confirmatory laboratory evidence:

• Isolation of a species of the family Vibrionaceae (other than toxigenic V. cholerae O1 or O139 which are reportable as cholera) from a clinical specimen

Supportive laboratory evidence:

• Detection of a species of the family Vibrionaceae (other than toxigenic V. cholerae O1 or O139 which are reportable as cholera) from a clinical specimen using a culture-independent diagnostic test (CIDT)

Epidemiologic linkage

A clinically compatible case that is epidemiologically linked to a case that meets the supportive or confirmatory laboratory criteria for diagnosis.

Criteria to distinguish a new case from an existing case

A case should not be counted as a new case if laboratory results were reported within 30 days of a previously reported infection in the same individual. When two or more different species of the family Vibrionaceae are identified in one or more specimens from the same individual, each should be reported as a separate case.

Case classification

Confirmed

• A case that meets the confirmed laboratory criteria for diagnosis.

Probable

• A case that meets the supportive laboratory criteria for diagnosis

OR

• A clinically compatible case that is epidemiologically linked to a case that meets the supportive or confirmatory laboratory criteria for diagnosis.

Interpretation note: Epi-linked probable cases can be epi-linked to either a confirmed or probable case, as long as the index case has a positive test result (see laboratory criteria above). Additionally, confirmed or laboratory-confirmed probable cases can include asymptomatic infections and infections at sites other than the gastrointestinal tract that are laboratory-confirmed (rare).

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• The Colorado State Public Health Laboratory (“State Lab”) provides testing services to support public health investigations. 
• The State Lab may test clinical and/or environmental samples when determined to be necessary for public health investigations. These services vary by pathogen but may include:
  • Testing for individuals who have been restricted or excluded from work or child care by public health
  • Testing for outbreak investigations, with prior approval from CDPHE
  • Other testing services as discussed with CDPHE
• The State Lab maintains a test directory, guidance for submitting samples, and other helpful resources on their webpage.
  • Additional questions can be directed to the Lab Coordinators by email (cdphe_labcoordinators@state.co.us; preferred method) or phone 303-692-3069.
• Clinical and commercial laboratories are required to submit Vibrio isolates or clinical material to the State Lab for confirmation and whole genome sequencing (WGS; i.e., molecular subtyping). While these submissions do not require prior approval from CDPHE, a complete lab requisition form is required for each isolate/clinical material submission to the State Lab.
  • WGS results are used for public health surveillance only and cannot be released to clinical providers or used for clinical decision-making. 
  • The State Lab does not perform routine antimicrobial susceptibility testing (AST); providers interested in AST should order it from a clinical or commercial laboratory.

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Interview all confirmed and probable (including epi-linked probable) cases of vibriosis to determine:

• Potential source of infection, and implement disease control measures as appropriate
• If others are ill (i.e., could this be an outbreak?) 

Local health departments have primary responsibility for interviews of sporadic cases in their jurisdictions. CDPHE is available to assist with case investigations upon request through CDPHE’s Enteric Disease Interview Team (EDIT). Interviews should be conducted and appropriate disease control measures implemented as soon as reasonably possible after the case is reported. Interviews should not be delayed until confirmatory laboratory testing is completed at the State Lab.

Forms 

For single cases, complete the investigation in the EpiTrax Investigation Form. This form incorporates the interview from the CDC Cholera and Other Vibrio Illness Surveillance Report form. Interview all cases, regardless of specimen source (stool, blood, wound, urine, etc.). 

The primary goal of interviewing is to determine the patient’s most likely source of infection and, if it is a food item that was consumed in the U.S., to gather enough information to be able to perform an investigation of an implicated establishment and/or provide detailed information to the state where the seafood was harvested.

The CDC Cholera and Other Vibrio Illness Surveillance Report form (Page 5) details the necessary information to collect for the investigation if the illness is suspected to be due to consumption of seafood in the United States. This page of the form has been transferred into EpiTrax as a separate Environmental Health Assessment form that will need to be completed and entered for each seafood exposure, even if they were consumed at the same establishment. The form can be accessed on the “Encounters” tab in EpiTrax, along with its instructions. 

There will be a section in the Environmental Health Assessment form regarding an environmental investigation and inspection. For Colorado exposures, this should be completed by the person interviewing the case, with input from an environmental health specialist who visits the implicated establishment. All information needs to be entered into the EpiTrax forms. 

If the suspected food item that caused illness was eaten in a state other than Colorado, complete as much of the Environmental Health Assessment form in EpiTrax as possible, and email CDPHE promptly. CDPHE will contact the state health department in which the exposure occurred to obtain the remaining information necessary for the investigation. This information will need to be added into the Environmental Health Assessment after the other state completes their investigation. 

If the case reports international travel, the investigation still needs to be completed for additional exposure information (food, water). Food establishment details such as restaurant names are not necessary, but general information on foods consumed or water exposures are needed. These details should also be placed in the Environmental Health Assessment form for raw or undercooked seafood exposures. 

For surveillance purposes, collect exposure histories for the seven days before symptom onset. Determining the exposure period can be difficult for cases who do not have an acute onset of gastrointestinal symptoms. It’s important to do a complete assessment for GI illness, even when the specimen was something other than stool to determine if any GI symptoms were present, even if mild. Use the following criteria to determine the case’s exposure period:

1. If the case reports diarrhea or vomiting, then use the onset date of diarrhea/vomiting to determine exposure period.
2. If the case does not report diarrhea or vomiting but reports other clinically relevant symptoms (see Clinical description section above), then use the onset date of other symptoms to determine exposure period.
3. If the case does not report onset of any clinically relevant symptoms (see Clinical description section above), then use the specimen collection date to determine exposure period.*

*Do not enter specimen collection date as “onset date” in EpiTrax (clinical tab); use this date to determine exposure period only. “Onset date” in EpiTrax only applies if the case experienced symptoms of illness. Otherwise, leave this field blank.

After completing the case interview, enter the information into the case’s morbidity record (CMR) in EpiTrax, including the investigation form, and conduct any necessary disease control activities. If the CDC forms were used during the investigation to collect information, all the information will need to be collected and entered into EpiTrax in the Standard Investigation form and Environmental Health Assessment form.  

If an outbreak is suspected, create a new outbreak in EpiTrax and contact CDPHE; this includes requests for additional testing at the State Lab.

Identify and evaluate contacts

Symptomatic contacts

• Unlike most other enteric illnesses, person-to-person transmission is not known to occur, so a detailed investigation of possible spread to others is not indicated. However, symptomatic contacts of a case should be investigated for shared exposures, including meals.
• Contacts of a case with a positive lab test who have clinically compatible symptoms are epi-linked probable cases and are treated the same as cases with a positive lab test for disease control purposes. See Disease control measures below.
• Complete a case interview with all epidemiologically linked probable cases.
• Epi-linked probable cases who have been interviewed should be entered into EpiTrax as a new, probable vibriosis morbidity record (CMR). Link this newly created CMR to the laboratory-confirmed case’s CMR under the “contacts” tab in EpiTrax.
• The Environmental Health Assessment form needs to be completed for epi-linked probable cases.
• Contact CDPHE to inform them if further environmental assessments need to occur for out-of-state epi-linked probable cases.
• Refer symptomatic individuals who have not previously been tested to their health care provider for stool testing and appropriate medical care.
• If a common source of exposure is suspected (e.g., a shared meal or social event), create an outbreak record in EpiTrax, and notify CDPHE as soon as possible.  

Reported incidence is higher than usual/outbreak suspected

If the number of reported cases of vibriosis in your jurisdiction is higher than usual, or if an outbreak is suspected, investigate the situation to determine the source of infection and mode of transmission. Notify CDPHE as soon as possible to discuss potential stool testing of untested, symptomatic contacts, and enter the outbreak into EpiTrax. CDPHE staff can assist local public health agencies to investigate outbreaks and determine disease control recommendations to prevent further cases, as well as coordinate surveillance of cases that cross county lines.

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Vibrio (Vibriosis) | CDC

Treatment

Vibrio enteritis usually resolves in less than a week without treatment. Patients with bloodstream or wound infections are treated with antibiotics and are usually hospitalized.

In general, individuals experiencing diarrhea are at risk of dehydration due to loss of fluids. If symptoms persist, worsen, or are severe, cases should promptly seek medical care.

Prophylaxis

No prophylactic treatment of close contacts is recommended.

Education

• Educate all cases about the risks of consuming raw or undercooked seafood or exposing wounds to seawater.
  • While marinating raw seafood in lime juice (commonly referred to as “ceviche”) may reduce the level of Vibrio bacteria, it does not eliminate the risks associated with consumption of raw seafood and can be a vehicle for Vibrio.
  • Although oysters should always be obtained from reputable sources, eating raw oysters or shellfish from “clean” waters or in restaurants with high turnover does not provide protection, since Vibrio naturally lives in waters where they are harvested.
• Keep raw and cooked shellfish separate to prevent cross-contamination. Wash hands thoroughly after handling raw shellfish, and clean cutting boards and surfaces immediately after use.
• Store raw shellfish and other seafoods away from other foods that will be eaten raw (e.g., fruits and vegetables) while in the refrigerator.
• Persons at high risk for Vibrio infections, including persons with liver disease, decreased gastric acidity, diabetes, peptic ulcers, or immunosuppression should not consume raw seafood, especially oysters.

Managing special situations

Non-cholera Vibrio spp. Infections are not known to be transmitted from person-to-person. In general, once the case’s symptoms resolve (including the resolution of diarrhea for at least 24 hours), the case may return to work or school and no further follow up is necessary.

Environmental measures

• If the likely source of a case’s Vibrio infection is a food item consumed in/from a Colorado establishment, the establishment should be inspected as soon as possible.
  • During the inspection, the environmental health specialist should obtain copies of the shellfish tags that accompanied the implicated seafood and should assess whether there is any evidence of mishandling at the establishment.
    • Bivalve Mollusk tags are required to be kept for 90 days by the federal food code. However, if the tags are unable to be collected, the closest dates surrounding the dining date should be collected instead. Report this in the EpiTrax notes that they are not the exact tags the case consumed.
  • This information should be added to the case’s morbidity record in EpiTrax (see Case investigation, Forms above) and forwarded to CDPHE as soon as possible after the inspection.
• If the likely source of a case’s infection is a food item consumed in the U.S., but not in Colorado, notify CDPHE as soon as possible; CDPHE will coordinate the seafood investigation with out-of-state agencies.
• Implicated food items must be removed from the environment. 
• If an out-of-state case consumed raw seafood in Colorado during their exposure period, the state will contact CDPHE and request an environmental assessment. CDPHE will reach out to the local jurisdiction to complete the investigation items (assessment and tag collection) to be forwarded back to the other state. 
• A decision about testing suspect/implicated food items must be made in consultation with CDPHE. 
  • The general policy of the State Lab and the Communicable Disease Branch is only to test food samples associated with outbreaks, not in single cases.

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American Academy of Pediatrics. Red Book: 2024-2027 Report of the Committee on Infectious Diseases, 33rd Edition. Illinois, Academy of Pediatrics, 2024.  

CDC Website: www.cdc.gov (“Diseases and Conditions”)

Daniels NA, MacKinnon L, Bishop R, et al. Vibrio parahaemolyticus Infections in the United States, 1973-1998. Journal of Infectious Diseases; 2000; 181:1991-6.

Heymann DL, ed. Control of Communicable Diseases Manual, 21st Edition. Washington, DC, American Public Health Association, 2022.

Hlady WG, Klontz KC. The Epidemiology of Vibrio Infections in Florida, 1981-1993. Journal of Infectious Diseases; 1996:173:1176-83.

National Center for Emerging and Zoonotic Infectious Diseases. Beam Dashboard. Vibriosis Surveillance and NORS View. https://www.cdc.gov/ncezid/dfwed/BEAM-dashboard.html Accessed: May 21, 2025.

National Center for Emerging and Zoonotic Infectious Diseases & Division of Foodborne, Waterborne, and Environmental Disease. (n.d.). Table 2. Estimated annual number of episodes of illnesses caused by 31 pathogens transmitted commonly by food, United States. https://www.cdc.gov/foodborneburden/pdfs/scallan-estimated-illnesses-foodborne-pathogens.pdf

Vibriosis (any species of the family Vibrionaceae, other than toxigenic Vibrio cholerae O1 or O139) 2017 Case Definition | CDC. (n.d.). https://ndc.services.cdc.gov/case-definitions/vibriosis-2017/

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CDPHE Communicable Disease Branch

• Phone: 303-692-2700 or 800-866-2759
• Fax: 303-782-0338
• After hours: 303-370-9395

CDPHE Lab Coordinators: 

• Email (preferred): cdphe_labcoordinators@state.co.us  
• Phone: 303-692-3069

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