FISH, AMPHIBIANS, AND REPTILES IN AQUACULTURE, LABS, AND SC WATERWAYS

Fish and their habitats, both fresh and saltwater, present a potential risk for infection from pathogenic organisms.  In a closed system such as a tank or aquarium, zoonotic organisms may be even more highly concentrated. The following precautions will minimize your chance of injury or infection when handling fish, reptiles, and amphibians in their aquatic habitat:

· Before beginning work, cover open wounds to prevent inoculation.

· Ill or immunocompromised individuals should obtain medical counsel regarding their ability to work safely with animals or in animal habitats.

· Wear gloves, boots, or other appropriate personal protective equipment, and wash hands with clean water and antimicrobial soap (or waterless hand cleaner) after working with aquatic animals or in their environments.  In labs, lab coats and safety glasses should be worn, and these should be washed separately from other clothing. It is unhealthy to bring aquatic organisms home to your family members. A normal, healthy adult may have only mild symptoms when infected with a zoonotic disease, but the same organisms can be fatal to infants, the elderly, and those with a weakened or suppressed immune system.

· Fecal- oral contamination (fish fecal material into your mouth) can expose you to diarrheal illnesses. Eating, drinking, smoking, and applying cosmetics (even lip balm) or contact lenses are not allowed in fish labs or while working with fish. Wash your hands immediately after contact with fish.

· Report sick fish immediately so they can be diagnosed and treated before the illness is spread.  Avoid handling fish with bare hands.   

If an injury occurs while handling fresh or saltwater fish, or while working in their habitat, immediately wash the area with clean water and antimicrobial soap.  (“Waterless” hand cleaner may be substituted until clean water is available). Follow the Clemson University Work Injury Protocol (call CompEndium Services at 877-709-2667 to arrange medical treatment.)  A tetanus booster (Td) may be needed if > 5 years since last booster. Watch for signs/symptoms of infection: pain, swelling, or redness, and possibly fever and/or chills. Any indication of infection requires immediate medical treatment to prevent further tissue damage or systemic involvement (i.e. cellulitis, sepsis). Photos of cellulitis are available at: http://www.emedicine.com/derm/topic464.htm

Persons who will be trapping/handling snakes will need additional training. Please contact the Occupational Health Nurse for referral for this training.  

The following aquatic organisms have been associated with zoonotic infection. Other zoonotic organisms could be present, but those listed below are thought to be the most likely to be encountered by persons handling fish, reptiles, and amphibians in Clemson fish labs and farms, and in SC waterways.

Aeromonas hydrophila is a gram-negative bacillus found in all freshwater environments, and probably has the greatest potential for causing infection in freshwater wounds. It can infect any wound, but persons with impaired immune systems due to illness or medication are most susceptible to infection. Symptoms include pain, swelling, or redness at the site, and possibly, fever and chills. These are true cases: 

Case 1. A 74-year-old white male with atherosclerotic cardiovascular disease presented with a 2-day history of pain and swelling in his right arm after impaling himself with a fish hook while fishing in the Savannah River. Incision and drainage of a subcutaneous abscess yielded pure culture of A. hydrophila. The patient improved rapidly with ciprofloxacin therapy.

Case 2. A 59-year-old white male diabetic with significant vascular disease on anticoagulant therapy lacerated his left thumb on a brim fish dorsal fin while fishing at Lake Hartwell in Georgia. He fell on his left forearm 24 hours later, sustaining a hematoma. 12 hrs. later he presented in septic shock with A. hydrophila bacteremia. Despite prompt therapy with ciprofloxacin and ceftazidime for 3 weeks, the patient developed necrotizing myositis of the left forearm muscles within 12 hours of admission. Four surgical wound debridements were unsuccessful, and an above-the-elbow amputation was subsequently necessary. This patient suggested that other people who fish might benefit from knowledge of the potential hazard of A. hydrophila. Suggested link for further information: http://vm.cfsan.fda.gov/~mow/chap17.html

Atypical Mycobacteria (M. fortuitum, M. marinum, M. chelonia):

Bacteria of the genus Mycobacterium, especially M. marinum and fortuitum, can be very harmful to aquarium fishes, but the method in which the tuberculosis bacteria first reach the aquarium and fish is unknown. These mycobacteria can occasionally cause transitory, superficial infections of cuts on the hands or forearms of aquarists through exposure in contaminated freshwater or saltwater tanks. Lesions can later form in the lungs and bronchial lymph nodes. Having exposed open wounds while working with infected tanks increases the risk of infection. Immunocompromised persons should take precautions to avoid infection. BMBL states to use BSL2 and ABSL2 for these organisms. Good reference for further information: http://www.goodwoodcourt.org/xalan/i_bacteria.htm

http://www.wa.gov.au/westfish/sf/broc/fhinfo/fhinfo03.html#top

Campylobacter spp. (Gram-negative bacilli) are the most common bacterial cause of diarrheal illness in the United States, usually associated with the ingestion of undercooked chicken or pork. It can also occur through inadequate hand washing after handling fish, amphibians, and reptiles (through inadvertent ingestion of the organism in infected water or animal feces). Signs/symptoms of campylobacteriosis are diarrhea, cramping, abdominal pain, and fever within 2 to 5 days after exposure to the organism. The diarrhea may be bloody and can be accompanied by nausea and vomiting. The illness typically lasts a week. Some persons who are infected with Campylobacter have no symptoms, but in persons with immunocompromise, Campylobacter occasionally spreads to the bloodstream and causes a serious life-threatening infection. The bacterium is fragile, can’t tolerate drying, and only grows if there is less than the atmospheric amount of oxygen present. Proper hand washing (preferably with an antimicrobial soap) after animal/cage/tank handling should or minimize the chance of infection for those who handle fish, reptiles, or amphibians.

Cryptosporidium nasorum (in fish), C. Serpentis (in reptiles), C. Meleagridis and C. Baileyi (in birds), and C. Muris (in rodents) are not generally considered to be infectious for humans. These Cryptosporidium spp. should not be confused with C. parvum, which infects mammals (causing severe, life-threatening disease in persons who are immunocompromised). 

Edwardsiella tarda is an opportunistic pathogen (Gram negative rod) occasionally causing acute gastroenteritis; associated with meningitis, septicemia, and wound infections. The reservoir is mammals, reptiles (intestinal tract of snakes), and water (contamination from reptiles and fish). The host range is mammals, aquatic mammals, reptiles, fish and occasionally humans. The transmission is fecal-oral and can be avoided by the use of careful handwashing. 

Erysipelothrix rhusiopathiae is a Gram-positive anaerobic rod, found where substances that contain nitrogen decompose. Usually found in swine, fish, poultry, clams, crabs, grease, and fertilizer. In mild cases, a rash will form, usually on the hands. In a more severe case, the rash will have raised blue-purple spots with sharply defined edges and is painful. The rash covers the peripheral body with clearing at the center body. Normally it is lasts 2 to 4 weeks and is benign, but has also been known to cause endocarditis. Antibiotic treatment is indicated, but E. rhusiopathiae has been found to be resistant to sulfonamides, aminioglycosides, trimethoprim-sulfamethoxazole, and vancomycin. Persons working in these areas should wear puncture-proof gloves and wash their hands frequently.

Escherichia coli infections are commonly spread by ingestion of food or water contaminated by human or animal feces.

Legionella spp. organisms can be found in many types of water systems, but the bacteria reproduce to high numbers in warm, stagnant water (90°-105° F). Outbreaks of legionellosis have occurred after persons have breathed mists that come from a water source (e.g., air conditioning cooling towers, whirlpool spas, showers) contaminated with Legionella bacteria. Persons may be exposed to these mists in homes, workplaces, hospitals, or public places. Symptoms usually include fever, chills, and a cough, and may also include muscle aches, headache, tiredness, loss of appetite, and, occasionally, diarrhea. 

Salmonella spp. are carried (and intermittently shed) by fish, amphibians and reptiles, which rarely display signs of infection but can cause acute gastroenteritis in humans. The infection can progress to meningitis, osteomyelitis, and urinary tract infections, with increased prevalence and severity in immunocompromised individuals. 

Streptococcus iniae is a Gram-positive bacterium. Humans can be infected if they injure themselves while handling fresh water fish. Symptoms include fever, swelling and pain near injury site. Treatment, usually antibiotics, is based upon the severity of the case.

Vibrio vulnificus can infect wounds sustained in coastal or estuarine waters. The lesions (sores) range from mild, self-limited lesions to rapidly progressive cellulitis and myositis that can spread rapidly and destructively. 

Febrile Illness Associated with Cleaning a Saltwater Fish Aquarium:During October 2001, a cluster of febrile illnesses occurred among persons in a household after cleaning a residential saltwater fish aquarium. Four persons were involved in cleaning the aquarium and four were visiting the household. All eight were hospitalized with fever, fatigue, vomiting, or diarrhea, and difficulty breathing which occurred with 24 hours after saltwater aquarium cleaning. Cleaning the 284-liter aquarium involved changing the carbon filter, replacing approximately 25% of the water, and boiling eight pieces of coral for 10 minutes each. No brushes or chemical cleansers were used. No Legionella, Plesiomonas, or protozoa were identified in any aquarium samples. The aquarium samples were positive for several Gram-negative bacilli (predominantly Acinetobacter lwoffii). Endotoxin levels were elevated in all aquarium samples, suggesting that inhalation of endotoxins from Gram-negative bacilli caused the illnesses; coral boiling was the likely mechanism of aerosolization.

Specific Precautions for Handling Frogs:Most amphibians pose no additional risk to humans, provided normal hand washing procedures are followed after working with animals, caging or feces. The habit of wearing plastic or latex gloves affords additional protection. Remember to not touch your own mucous membranes (e.g. rub your eyes)   after handling frogs. Secretions from their parotid glands rubbed into the conjunctival sac of the human eye can range from irritating to very painful.

If an injury occurs while handling fresh or saltwater fish, or while working in their habitat, immediately wash the area with clean water and antimicrobial soap. (“Waterless” hand cleaner may be substituted until clean water is available). Follow the Clemson University Work Injury Protocol (call CompEndium Services at 877-709-2667) to arrange medical treatment referral. A tetanus booster (Td) may be needed if > 5 years since last booster. Watch for signs/symptoms of infection: pain, swelling, or redness, and possibly fever and/or chills. Any indication of infection requires immediate medical treatment to prevent further tissue damage or systemic involvement (i.e. cellulitis, sepsis). Photos of cellulitis are available at: http://www.emedicine.com/derm/topic464.htm

Additional Precautions:

Amphibians: Most amphibians pose no additional risk to humans, provided normal hand washing procedures are followed after working with animals, caging or feces. The habit of wearing plastic or latex gloves affords additional protection. However, remember to not touch your own mucous membranes (e.g. rub your eyes) after handling frogs. Secretions from their parotid glands rubbed into the conjunctival sac of the human eye can cause discomfort ranging from irritating to very painful.

Excellent websites for further information:

http://www.ahsc.arizona.edu/uac/notes/classes/coldblood/coldbldverteb02.htm#Models

http://library.thinkquest.org/22403/data/diseases/disease.html

A “fun” website devoted exclusively to AXOLOTLS: http://www.caudata.org/axolotl/

This page was updated on August 10, 2004, and is maintained by Sue Pedrick in the Joseph F. Sullivan Center of the College of Health, Education,and Human Development

© Medical Surveillance Program * Clemson University * Clemson, South Carolina, 29634