Stanford University

Working Safely with Aquatic Animals

Zoonoses are diseases that animals can transmit to humans. The following guide details the occupational hazards associated with aquatic animals, as well as the precautions necessary for minimizing the risk of animal-to-human disease transmission. Contacts are provided for further assistance.

How Can I Protect Myself?
  1. When working with aquatic animals, take the following protective measures:

    • When working in a laboratory environment, wear appropriate PPE, including gloves and laboratory coat, or other dedicated protective clothing. 
      • Wear sturdy, appropriate length waterproof gloves and/or protective sleeves on top of a lab coat when handling aquarium water, animals in aquarium water, or when there is a possibility of exposure of aquarium water to the arms.
      • For splash protection, a face shield, mask or protective eyewear may also be indicated.
      • If a large splash hazard exists, consider a fluid-resistant laboratory coat or other dedicated protective clothing.
    • When working in the field, wear appropriate protective clothing suited to the hazards at hand, the task being performed, and the environment in which the work is conducted.
    • While working in an animal use area, do not eat, drink, or apply cosmetics.
    • Wash hands and arms after handling animals and aquarium water. Avoid touching your face, eyes, nose or mouth with unwashed hands or contaminated gloves.
    • Cover abraded skin, cuts, scrapes or sores and do not allow wound contact with aquatic animals, contaminated materials or aquarium water. 
    • Be aware that unfixed tissues, body fluids, and other materials derived from aquatic animals may also pose a risk.

    Contact EH&S at (650) 723-0448 for any concerns or questions you have about working with aquatic animals or for any concerns or questions regarding vertebrate animals and occupational risks. Help with training personnel in specific work practices to minimize risk can be obtained by contacting the Veterinary Service Center (VSC), at (650) 723-3876.

    Note that all personnel working with aquatic animals or vertebrate animals are eligible to enroll in the Laboratory Animal Occupational Health Program (LAOHP). Contact EH&S at (650) 723-0448 for additional information.

If You Work With Aquatic Animals
  1. Aquatic animals are susceptible to zoonotic diseases such as Mycobacteriosis (Marinum, Liflandii, Chelonae), Chlamydiosis, Salmonellosis, Aeromonas, and Campylobacter, as well as others.  Contaminated tank water also poses health risks in transmitting diseases to both aquatic amphibians and humans.

    In research studies or teaching demonstrations, animals should be procured from VSC “approved vendors.”  If none exist thenProtocol Directors (PD) should quarantine and inspect animals prior to use.  PDs may also secure quarantine and inspection services from VSC. . When working with wild-caught animals or in the field, consider local conditions, including any known outbreaks, when evaluating potential exposures.

    This page describes some examples of the causative agents and potential illness associated with aquatic animals, particularly fish, frogs and turtles, along with protective measures, signs of illness, what to do if an exposure or injury occurs, and links to additional information on-line.

    Mycobacterium sp. 

    Mycobacterium sp. (including marinum, liflandii, and chelonae) can be found in fish and amphibians. Humans are typically infected by contamination of lacerated or abraded skin with aquarium water or fish contact. Symptoms can include dermatitis, nodules under the skin, lesions or skin loss. Lesions typically present as less than 2-cm-diameter, nodular, reddened swellings in the skin and joints of the extremities. Immunosuppressed persons can develop lymphadenitis & pulmonary disease similar to tuberculosis or more severe disseminated disease. Antibiotic therapy is generally effective for aquatic mycobacterial infections in humans, although surgical excision of lesions may be required.

    Additional information:

    Aeromonas sp.

    Aeromonas sp. are gram-negative bacteria that are commonly found in freshwater habitats. Infections can occur through wound exposure or accidental ingestion of contaminated water or other materials. People can become infected through open wounds or by drinking contaminated water. Young children or immunocompromised individuals are more likely to acquire infections. Symptoms may include diarrhea or blood infections. The disease is generally treatable with oral antibiotics.

    Additional information:

    Salmonella sp.

    Salmonella sp. are members of the Enterobacteriaceae family. Individuals can contract salmonellosis by touching infected feces from animals or aquatic environments containing infected feces. Infected individuals can experience fever, nausea, diarrhea and abdominal pain. Individuals with weakened immune systems are more likely than others to develop severe illness. 

    Additional information:

    Campylobacter sp.

    Campylobacter is the most common bacterial cause of diarrheal illness in the United States. Campylobacter can be found in contaminated aquatic environments and seafood. Symptoms of Campylobacter infection include diarrhea, fever, and stomach cramps. Individuals with weakened immune systems are more likely than others to develop severe illness. 

    Additional information:


    Chlamydia pneumoniae typically causes respiratory infections, and may be found in frogs. Exposure can occur through handling infected animals or exposure to contaminated aquarium water. Symptoms include runny or stuffy nose, fatigue (feeling tired), low-grade fever, hoarseness or loss of voice, sore throat, slowly worsening cough that can last for weeks or months, and headache.

    Additional information:

    Clostridium botulinum

    Clostridium botulinum is a gram positive bacterium that can be found in fish intestines as well as environmental sediments and decaying organic matter. They produce potent paralytic neurotoxin that can cause human botulism when ingested. Transmission can occur through open wounds, mucous membrane exposure, or ingestion. Symptoms include double vision, drooping eyelids (ptosis), slurred speech, difficulty swallowing and muscle weakness that is symmetric and descends through the body (first shoulders are affected, then upper arms, lower arms, thighs, calves, etc.). Symptoms can take up to 2 weeks to appear.

    Additional information:

    Edwardsiella tarda

    Edwardsiella tarda is a gram negative bacterium that can be found in fish, reptiles, and amphibians. Infections in humans can occur through ingestion of contaminated tissue or aquarium/ocean water, or dermal contact with infected fish. Human infections with E. tarda are characterized primarily by bacterial gastroenteritis, although wound infections and systemic conditions, such as septicaemia and meningitis, are also observed, as are extraintestinal infections.

    Additional information:

    Erysipelothrix rhusiopathiae

    Erysipelothrix rhusiopathiae is a gram positive bacterium that is commonly found in soil and water and has been found on surfaces of marine fish.  Human infections with E. rhusiopathiae occur via wound exposure when handling contaminated fish. Individuals who contract infections typically have localized, painful, self-limiting cellulitis, with purple discoloration and oedema (‘fish rose’). Individuals may also develop a local skin infection, a widespread skin infection or a systemic infection which can spread to the heart and heart valves.

    Additional information:

    Escherichia coli

    1. coli is found in a number of animal species, and may be prevalent in associated contaminated soil or water. Infection can be associated with exposure to contaminated water, and can result in diarrhea, stomach cramping or nausea.

    Additional information:

    Plesiomonas shigelloides

    Plesiomonas shigelloides is a gram negative bacterium that can be found in both fresh and saltwater environments. Infection has been associated with water exposure, fish handling, or ingestion of seafood or aquarium water. Infected individuals can experience watery diarrhea and abdominal pain.

    Additional information:


    Spirometra sp. is globally distributed, though sparganosis cases are uncommon in North America. Humans can develop sparganosis by acting as a paratenic or second intermediate host for Spirometra sp. Individuals can contract sparganosis by drinking contaminated water or ingestion of an intermediate host. Intermediate hosts of Spirometra sp. include small crustaceans or vertebrates including fish, frogs, snakes, and other reptiles. Larva can not develop into adult worms in human intestines, but can lodge in the brain parenchyma, spinal cord or eye, causing seizures, headache, hemiparesis, blindness, paralysis, or death.  

    Additional information:

    Streptococcus iniae

    Streptococcus iniae are gram positive bacteria that are commonly found in freshwater and marine fish. Infections in humans are primarily associated with processing or handling live or dead fish, especially if the human has any open wounds. S. iniae infections can cause cellulitis, arthritis, endocarditis, meningitis or death. 

    Additional information:

    Vibrio sp.

    Vibrio sp. bacteria are widely distributed in marine and estuarine environments. Vibrio sp. infections in humans are associated with skin wounds, ingestion, or exposure to aquarium water. Infected individuals can experience gastroenteritis, septicemia, or wound infection. Individuals with weakened immune systems are at a higher risk of developing severe infection or illness.

    Additional information:

Who is at Risk for Infection
  1. Those at risk include investigators, animal technicians, laboratory personnel, or others who routinely handle aquatic amphibians, their tissues, and water tanks. At higher risk are people with suppressed immune systems who are generally more susceptible to infections. Scratches or cuts involving aquatic amphibians or injuries from objects contaminated with body tissues or unprotected exposure of cuts or wounds to water containing the amphibians require immediate first aid and medical attention.


    Between the hours of 8 am and 5 pm, Monday through Friday, contact the Stanford University Occupational Health Center (SUOHC) at (650) 725-5111 for immediate phone triage and to schedule an urgent drop-in appointment time.

    For immediate, life-threatening injuries, or when SUOHC is closed, go directly to the Stanford University Medical Center Emergency Department.

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