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.
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.
- For Field Research, contact ehs_field_safety_support@lists.stanford.edu.
- 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.
- When working in a laboratory environment, wear appropriate PPE, including gloves and laboratory coat, or other dedicated protective clothing.
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:
- Canada Dept. of Public Health Pathogen Safety Data Sheets: Mycobacterium sp.
- Center for Food Security and Public Health, Iowa State University Disease Information: Piscine Mycobacteriosis
- CDC Reptiles and Amphibians | Healthy Pets, Healthy People
- CDC Nontuberculous Mycobacteria (NTM) Infections
- UC San Francisco, Zoonoses
- University of Virginia, Zoonotic Considerations for Frog Handlers
- UC Santa Cruz, Information on Zoonotic Diseases
- Princeton University, Zoonoses Associated with Fish and Amphibians
- University of Idaho, Zoonoses Associated with Fish
- Texas State University, Working With Aquatic Species
- Valdosta State University, Working Safely with Fish: Preventing Injury and Zoonotic Disease Transmission
- Medicine Net Mycobacterium marinum
- Medscape Mycobacterium Chelonae: Background, Pathophysiology, Epidemiology
- Zoologix PCR test for Mycobacteriosis in Amphibians
- Emerging Infectious Diseases, Extrapulmonary Infections Associated with Nontuberculous Mycobacteria in Immunocompetent Persons
- Emerging Infectious Diseases, Mycobacterium liflandii Infection in European Colony of Silurana tropicalis
- Comparative Medicine, Disease attributed to Mycobacterium chelonae in South African clawed frogs (Xenopus laevis)
- Mycobacteriosis in Amphibians
- The Veterinary Journal, Bacterial zoonoses of fishes: A review and appraisal of evidence for linkages between fish and human infections
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:- Canada Dept. of Public Health Pathogen Safety Data Sheets: Infectious Substances: Aeromonas hydrophila
- CDC Reptiles and Amphibians | Healthy Pets, Healthy People
- Purdue University Aeromonas Hydrophila Infection In Fish
- UC San Francisco, Zoonoses
- Princeton University, Zoonoses Associated with Fish and Amphibians
- UC Santa Cruz, Information on Zoonotic Diseases
- University of Idaho, Zoonoses Associated with Fish
- Texas State University, Working With Aquatic Species
- Valdosta State University, Working Safely with Fish: Preventing Injury and Zoonotic Disease Transmission
- Scientific World Journal, Emerging Aeromonas Species Infections and Their Significance in Public Health
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:
- Canada Dept. of Public Health, Pathogen Safety Data Sheets: Salmonella enterica sp.
- Center for Food Security and Public Health, Iowa State University, Disease Information: Salmonella (Reptile-associated)
- Center for Food Security and Public Health, Iowa State University, Disease Information: Salmonella (Nontyphoidal)
- CDC Reptiles and Amphibians | Healthy Pets, Healthy People
- FDA, Pet Turtles: Cute But Commonly Contaminated with Salmonella
- University of Virginia, Zoonotic Considerations for Frog Handlers
- UC Davis, Care and Use of Turtles & Tortoises
- Princeton University, Zoonoses Associated with Fish and Amphibians
- Oregon State, Care and Use of Frogs
- University of Idaho, Zoonoses Associated with Fish
- Texas State University, Working With Aquatic Species
- Valdosta State University, Working Safely with Fish: Preventing Injury and Zoonotic Disease Transmission
- Ireland Health Protection Surveillance Centre, Reptiles and Risks of Infectious Diseases
- Salmonella and Other Zoonoses: The Basics
- Risk of Catching Zoonotic Diseases from Your Reptile
- Reptiles: Zoonoses
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:
- CDC, Campylobacter (Campylobacteriosis)
- UC Davis, Care and Use of Turtles & Tortoises
- FDA, BAM Chapter 7: Campylobacter
- University of Idaho, Zoonoses Associated with Fish
- Ireland Health Protection Surveillance Centre, Reptiles and Risks of Infectious Diseases
Chlamydiosis
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:
- CDC, Chlamydia pneumoniae Infection
- University of Virginia, Zoonotic Considerations for Frog Handlers
- Princeton University, Zoonoses Associated with Fish and Amphibians
- Veterinary Pathology, Pathology of naturally occurring chlamydiosis in African clawed frogs (Xenopus laevis)
- Emerging Infectious Diseases, Chlamydia pneumoniae Infection in a Breeding Colony of African Clawed Frogs (Xenopus tropicalis)
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:
- Canada Dept. of Public Health, Pathogen Safety Data Sheets: Clostridium botulinum
- Center for Food Security and Public Health, Iowa State University, Disease Information: Botulism
- FDA, BAM Chapter 17: Clostridium botulinum
- Ireland Health Protection Surveillance Centre, Reptiles and Risks of Infectious Diseases
- The Veterinary Journal, Bacterial zoonoses of fishes: A review and appraisal of evidence for linkages between fish and human infections
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:
- Canada Dept. of Public Health, Pathogen Safety Data Sheets: Edwardsiella tarda
- University of Idaho, Zoonoses Associated with Fish
- Canadian Journal of Infectious Disease and Medical Microbiology, Edwardsiella tarda bacteremia. A rare but fatal water- and foodborne infection: Review of the literature and clinical cases from a single centre
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:- University of Idaho, Zoonoses Associated with Fish
- The Veterinary Journal, Bacterial zoonoses of fishes: a review and appraisal of evidence for linkages between fish and human infections
- Veterinary Microbiology, Erysipelothrix rhusiopathiae
Escherichia coli
- 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:
- University of Idaho, Zoonoses Associated with Fish
- Center for Food Security and Public Health, Iowa State University, Disease Information: Escherichia coli 0157:H7
- Canada Dept. of Public Health, Pathogen Safety Data Sheets: Escherichia coli, enterohemorrhagic
- Canada Dept. of Public Health, Pathogen Safety Data Sheets: Escherichia coli, enteroinvasive
- Canada Dept. of Public Health, Pathogen Safety Data Sheets: Escherichia coli, enteropathogenic
- Canada Dept. of Public Health, Pathogen Safety Data Sheets: Escherichia coli, enterotoxigenic
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:
- Canada Dept. of Public Health, Pathogen Safety Data Sheets: Plesiomonas shigelloides
- Clinical Microbiology Revisited, Plesiomonas shigelloides Revisited
- CDC MMWR, Epidemiologic Notes and Reports Aquarium-Associated Plesiomonas shigelloides Infection — Missouri
Sparganosis
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:
- CDC, Sparganosis
- Oregon State, Care and Use of Frogs
- Handbook of Clinical Neurology, Other cestodes: sparganosis, coenurosis and Taenia crassiceps cysticercosis
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:
- Center for Food Security and Public Health, Iowa State University, Disease Information: Streptococcosis
- University of Idaho, Zoonoses Associated with Fish
- Emerging Infectious Diseases, Towards Control of Streptococcus iniae
- Veterinary Microbiology, Streptococcus iniae: an aquatic pathogen of global veterinary significance and a challenging candidate for reliable vaccination
- The Veterinary Journal, Bacterial zoonoses of fishes: A review and appraisal of evidence for linkages between fish and human infections
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:
- Canada Dept. of Public Health, Pathogen Safety Data Sheets: Vibrio cholerae
- Canada Dept. of Public Health, Pathogen Safety Data Sheets: Vibrio parahaemolyticus
- CDC, Vibrio Species Causing Vibriosis
- University of Idaho, Zoonoses Associated with Fish
- Vibrio sp. infections
- The Veterinary Journal, Bacterial zoonoses of fishes: A review and appraisal of evidence for linkages between fish and human infections
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.