Fish Disease and Human Health-

Infections or infestations of animals that can be transmitted to humans are called zoonoses. There are a few diseases of fish that aquaculture hobbyists need to be conscious of when handling fish. 

The majority of the following content relates directly to diseases contracted by humans from contamination through non-digested means.

Mycobacteriosis/Nocardiosis

Rainbow trout with mycobacteria lesions

Mycobacteriosis and nocardiosis are bacterial diseases that affect a wide range of freshwater and marine fish, but particularly aquarium fish. The bacteria cause chronic systemic infections that form lesions internally and externally. Affected aquarium fish exhibit several symptoms such as anorexia, popeye, skin discolouration and external lesions such as ulcers, nodules and fin rot. Cold water salmonids may show no external signs of disease other than mortality, but upon post mortem, greyish-white lesions may be seen in the kidney, liver and spleen. There is some debate as to whether infected fish can be successfully treated for these bacterial diseases and destruction of infected stock and comprehensive disinfection of premises is usually recommended.

Several species of these bacteria are capable of infecting man. The bacteria enters the skin as a result of abrasions incurred in swimming pools, tropical fish aquaria or from handling guts of infected fish, and may produce skin granulomas of the elbow, knees, fingers and feet.

The condition may persist for quite some time and must be treated with antibiotics for an extended period.

Symptoms

• Three to four weeks after the bacteria enters the skin, a swelling develops over a bony prominence or the site of an abrasion.
• A cyst, or abscess develops, that may be filled with pus and may ulcerate and scar.
• Swelling of the lymph nodes may occur.

Mycobacterium marinum Infection - Forearm, Fish Tank Granuloma

 

Mycobacterium marinum Infection - Forearm, Sporotrichoid Presentation.
Granuloma

 

Mycobacterium marinum Infection - Dorsal hand, Sporotrichoid Presentation.
Granuloma

Treatment

• Treatment with some antibiotics is possible, but tests are usually required to determine the sensitivity of the bacteria to the antibiotic to be administered.
• Spontaneous cures may take up to two years, although most signs clear in a few months.

Prevention

• Wear protective gloves when cleaning fish aquaria, disinfect equipment, and aseptic skin tissue with an "Intermediate Level Microbial" product afterwards.

Have you ever thought that you were immune to the diseases and parasites from fish and your pond?  Well your not, and to minimize the potential of infection or cross-contamination some additional precautions may need to be implemented. This possibility is especially true if you are a diabetic, or have a medical condition where pathogens can find an easy path into your body. With diabetics ( I am a Type-1 diabetic) the transport channel is through the fingers or arms where "finger sticks" are performed daily, whereas the punctures do not heal completely for hours. Also, the risk could be greater if you are on a blood thinner like Coumadin® from due to a heart fibrillation condition.  Don't forget you could be the transport mechanism for certain things your Koi is experiencing.
                                                                                                                   
Would you ever scrape the mucous layer off your Koi, and spread it on your turkey sandwich for lunch?
 Practically you test the effectiveness of your Immune System like this everyday, and whether your resistance is lower than ideal determines the pathogens success rate of infection. Please consider adopting and implementing an aseptic and disinfectant protocol (see below) when handling Koi by utilizing some of these products.

Anisakid nematodes

Anisakis worms in the viscera of a blue mackeral

Anisakis and anisakis-like parasites are common nematode worms, the larvae of which infect many species of locally caught fish. It has a complicated lifecycle with many intermediate hosts, and may be transmitted several times from fish to fish before the final host is reached.

Anisakis larvae are 10-50 mm in length, white and normally tightly curled in a cyst in the guts and muscle of the fish.

A simple life cycle of Anisakis nematodes

Symptoms

• Severe gastric and intestinal pain, vomiting, and diarrhoea.
• In some severe cases fever and blood in the stools may occur.
• Note: Anisakiasis is often misdiagnosed a stomach ulcers or appendicitis.

Treatment

• Affected tissue in the intestines must be removed by surgery, or by fibergastroscopy if lodged in the stomach wall. This is the only treatment option.

Reprinted from the Dept. of Dermatology - University of Iowa College of Medicine

 

Photobacterium

Species associated with infection - P. damselae (previously Listonella demsela and Vibrio damsela)

Associated with necrotising wound infection - associated with sea water exposure

Reorted susceptible to penicillins, tetracycline and chloramphenicol

Reference - Coffey, J.A., Harris, R.L., Bradshaw, M.W., Williams, T.W. (1986). Vibrio damsela: another potentially virulent marine vibrio. J. infect. Dis. 153, 800-802.

Vibrio

V. alginolyticus - associated with wound and ear infection - associated with aquatic exposure -

V, carchariae - associated with wound infection following shark bite - reported susceptible to cephalosporins, chloramphenicol, gentamicin - may require debridement

V. cholerae - the agent of cholera - rehydration and tetracycline are used for treatment

C. cincinnatiensis - associated with bacteraemia - reported susceptible to moxalactam, chloramphenicol and cephalosporins

Vibrio damsela (see Photobacterium damselae)

V. fluvialis, V. furnissii, V. hollisae, V. metschnikovii, V. mimicus, V. parahaemolyticus - associated with diarrhoea and septiciaemia -associated with ingestion of contaminated water or shellfish - reported susceptible to tetracycline and chlormaphenicol

V. vulnificus - associated with wound infection, septicaemia, meningitis, endometritis - reported susceptible to tetracycline, penicillins, gentamicin, chloramphenicol - associated with aquatic exposure and penetrating fish injury - may require debridement

References - West, P.A. (1989). The human pathogenic vibrios - a public health update with environmental perspectives. Epidem. Infect. 103, 1-34. - Pavia, A.T., Bryan, J.A., Maher, K.L., Hester, T.R., Farmer, J.J.Vibrio carchariae infection after a shark bite. Ann. intern. Med. 111, 85-86. - Bode, R.B., Brayton, P.R., Colwell, R.R., Russo, F.M., Bullock, W.E. (1986). Vibrio cincinnatiensis causing meningitis: successful treatment in an adult. Ann. intern. Med. 104, 55-56. - Hickman-Brenner, F.W., Farmer III, J.J., Hollis, D.G., F.W., Fanning, Steigerwalt, A.G., Weaver, R.E., Brenner, D.J. (1982). Identification of Vibrio hollisae sp. nov. from patients with diarrhea. J. clin. Microbiol. 15, 395-400. - Jean-Jacques, W., Rajashekaraiah, K.R., Farmer III, J.J., Hickman, F.W., Morris, J.G., Kallick, C.A. (1981). Vibrio metschnikovii bacteremia in a patient with cholecystitis. J. clin. Microbiol. 14, 711-712. - Bonner, J.R., Coher, A.S., Berryman, C.R., Pollock, H.M. (1983). Spectrum of Vibrio infections in a Gulf coast community. Ann. intern. Med. 99, 464-469 - Levine et al.(1993). Vibrio infections on the Gulf Coast: results of first year of regional surveillance. J. infect. Dis. 167, 479-483.

 

 

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Recent External Contributions- I wish to thank these kind individuals for their time sending these additions to this page. 

Louise Richens CEFAS Aquaculture and Fish Health, Diagnostic Microbiology Function Manager writes- 

In addition the following parasitic infections might have some relevance.  Parasites  Anisakis spp. (Anisakiasis, also named larval migrans visceral or eosinophilic granuloma. Transmitted by eating raw or minimally processed infected fish) Crytosporidium parvum (causing diarrhoea)

 

Myriam Algoet, DVM CEFAS Aquaculture and Fish Health, Microbiology team leader writes-

There are indeed a number of reported cases of such transmissions. Below is a list of fish associated bacterial (bacteria and commensals), which have been reported to affect humans. A full review & relevant references can be found in Austin & Austin, Bacterial fish pathogens (Springer - Praxis Ed, 1999, 457 pp, ISBN 1852331208): Bacteria Aeromonas hydrophila (causing diarrhoea and septicaemias) Campylobacter jejuni (gastro-enteritis) Clostridium botulinum type E (botulism) Edwarsiella tarda (diarrhoea) Erysipelothrix rhusiopathiae (fish rose) Leptospira interrogans (leptospirosis - Weil's disease) Mycobacterium fortiutum (mycobacteriosis; fish tank granuloma) Mycobacterium marinum (mycobacteriosis; fish tank granuloma) Plesiomonas shigelloides (gastro-enteritis) Pseudomonas aeruginosa (wound infections) Pseudomonas fluorescens (wound infections) Salmonella spp. (food poisoning) Streptococcus iniae ('mad fish disease) Vibrio cholerae-non 01 (Not causal agent of Cholera but does cause gastro-enteritis) Vibrio parahaemolyticus (food poisoning) Vibrio vulnificus (wound infections) The source of some of these organisms may well be the polluted waters in which the fish are to be found (including water fish are transported in). A comparative few are from diseased fish. Therefore, the transfer to humans will probably reflect the handing of diseased specimens. Uptake into humans may be via cuts, grazes, or less likely, via the digestive tract. 

 

World News Articles- Aquatic Infectious Diseases

August 9, 2002 Reprinted from Standard Times Newspaper

Rare bacterial infection kills Marion man, 69
By ERIC MOSKOWITZ, Standard-Times staff writer

MIKE VALERI/The Standard-Times Some members of Al Holt's family, from left, Debbie Silverman, his daughter; Linda Holt, his widow; and Norman Holt, his son, share memories about his life at Linda's home in Marion.

MARION -- For Al Holt, early retirement due to partial hearing loss from his Army days gave him more time to do the things he cared most about: fishing, golfing and spending time with his nine grandchildren.
Like every morning, Mr. Holt, 69, was up at sunrise July 15, making his way to the docks by 6. He went out on the Sea Witch, a 24-foot wooden surf hunter he'd built in 1968 with the help of a friend, Nat Mendell. He caught some fish, which he planned to eat later. And he came home complaining of soreness in his pinkie finger.
Two weeks later, Albert E. Holt Jr. was dead.
The cause? A rare flesh-eating bacteria.
Doctors at Boston's New England Medical Center called it photobacterium damsela, a rare but virulent marine pathogen that strikes faster than other, better-known forms of flesh-eating bacteria.
"This is a fishing community. We wouldn't want what happened to Al to happen to someone else. It was horrendous," Linda Holt, Al's wife of 17 years, said yesterday, urging others who come home from fishing complaining of pain or soreness to see a doctor immediately.
That Monday, the 15th, Linda came home from her office job at the Acushnet Co. at 5 p.m. and found Al with a sore pinkie.
"I said, 'All right, Al, worry about it later. It's just a baby finger,'" Mrs. Holt recalled. But when he insisted, they went to Wareham's Tobey Hospital, where a doctor suspected the swelling was gout, sending him home with some anti-inflammatory medication and instructions to ice it.
By 9 p.m., the pain was unbearable, even by Al's tough standards. Just two weeks earlier, he'd caught a fish hook in each hand while taking a bluefish off the line. Norman, his youngest son, cut one of them out ("That shows you his tolerance for pain," said Russell, Norman's older brother). The other, imbedded too deeply, was removed at Tobey.
So Linda took Al back to the hospital, his hand now fully swollen, a mottled red color. The same doctor admitted he'd never seen something like this, so Al -- at Linda's urging -- was rushed to New England Medical Center.
Over the next 24 hours, he went through four, four-hour surgeries. Doctors first tried to open his hand, suspecting an infection. What they found was a flesh-eating bacteria consuming the fascia, a layer of tissue enveloping the muscle. By Tuesday night, they had removed his hand, then his arm, then portions of his back and side in an attempt to stay ahead of the bacteria, which consumes soft tissue.
Necrotizing fasciitis is commonly caused by Group A strep infection, afflicting some 1,500 people per year, said Dr. Bela Matyas, medical director of epidemiology for the state Department of Public Health. But a 2000 New England Journal of Medicine article reported just 17 known cases of this faster-moving bacteria.
With his vital organs shutting down, Al was put on a ventilator, on kidney dialysis, on life support. The nature of the original wound -- a fish hook, a fin prick, however small -- is unknown, because Al never came to. Life support was turned off July 30. Ever a fighter, Al died 38 hours later.

Links related to this bacteria-
http://www.avl.co.uk/newsf.html
http://www.doh.state.fl.us/Disease_ctrl/epi/Epi%20Updates/2000/eu000405.htm
http://www.cdc.gov/ncidod/eid/vol5no6/davis.htm
http://www.animalnetwork.com/fish2/aqfm/1999/may/features/1/default.asp

Necrotizing Fasciitis Due to Photobacterium damsela in a Man Lashed by a Stingray

The following letter appeared in the New England Journal of Medicine on March 16, 2000 (Vol. 342, No.11):

To the Editor:

A variety of vibrio species can cause gastroenteritis, wound infections, and primary septicemia as well as illness among marine organisms. (1,2) Photobacterium damsela (formerly Vibrio damsela) is similar to other species of the genus vibrio, which are halophilic, gram-negative bacilli. (3) We describe a 43-year-old man with necrotizing fasciitis as a result of a laceration inflicted by a stingray while he was stepping off his sailboat in Tampa Bay, Florida.

The patient first presented to the emergency department of another hospital, where the wound to his right tibialis anterior muscle was irrigated and sutured approximately six hours after admission. Antimicrobial therapy was not prescribed, and the patient was released from the emergency department. Three days later, fever developed and erythema appeared along the wound margins, followed within the next 24 hours by the appearance of a 2.5-cm, malodorous, fluctuant lesion. The patient then came to our emergency department. His oral temperature was 39°C, his white-cell count was 15,500 per cubic millimeter, and he had a septic appearance. There was necrotizing fasciitis of his right tibialis anterior muscle. Administration of intravenous doxycycline (400 mg per day), cefazolin (3 g per day), and tobramycin (6.5 mg per kilogram of body weight per day) was begun and was continued until his discharge, seven days later. Deep surgical debridement of skin, fascia, and muscle was performed on an emergency basis, and the wound was again debrided in the operating room the following morning. Wound cultures yielded P. damsela, which was sensitive to our battery of antibiotics for gram-negative organisms, with the exception of amikacin, to which it had intermediate sensitivity. As an outpatient he received oral doxycycline and cephalexin for two weeks. Subsequently, he required physical therapy and a split-thickness skin graft for wound closure.

P. damsela is a pathogen in both immunocompromised and healthy hosts and can cause rapid, fulminant infection with a high rate of death. (2,4) Clinicians should be aware of this organism and other vibrio species, particularly in cases of wounds exposed to salt or brackish water or wounds inflicted by marine animals living in such an environment.

Gerard R. Barber, R.Ph., M.P.H.
Jeffrey S. Swygert, M.D.
Lakeland Regional Medical Center
Lakeland, FL 33804

References

1. Morris JG Jr, Black RE. Cholera and other vibrioses in the United States. N Engl J Med 1985;312:343-50.

2. Shin JH, Shin MG, Suh SP, Ryang DW, Rew JS, Nolte FS. Primary Vibrio damsela septicemia. Clin Infect Dis 1996;22:856-7.

3. McLaughlin JC. Vibrio. In: Murray PR, Baron EJ, Pfaller MA, Tenover FC, Yolken PH, eds. Manual of clinical microbiology. 6th ed. Washington, D.C.: American Society for Microbiology, 1995:465-76.

4. Fraser SL, Purcell BK, Delgado B Jr, Baker AE, Whelen AC. Rapidly fatal infection due to Photobacterium (Vibrio) damsela. Clin Infect Dis 1997;25:935-6.

Vaccine Link for Damsela