Fish TB (Mycobacterium marinum) FAQ , by Dr. Adrian Lawler

Fish TB (Mycobacterium marinum) FAQ

by Dr. Adrian Lawler
(retired) Aquarium Supervisor (l984-l998) J. L. Scott Aquarium Biloxi, Ms 39530

Original to Aquarticles

I continue to get more enquiries from people wanting to learn more about fish TB (Mycobacterium marinum) or some other pathogen from a fish tank, or from fishing or swimming waters, etc. I also continue to get emails from people who want me to give them the magic solution to cure their fish TB infection agony ASAP.

I also receive comments and questions from various students/scientists concerning fish TB in humans. One of latest is from a Ph.D. student at the University of Buea, Cameroon, who points out fish TB is a problem in that area because fishermen with AIDS, trying to feed their families by fishing in mangrove waters, are getting infected with fish TB. Much work needs to be done on this aspect of human fish TB infection.

In this short article I've listed some frequently asked questions (FAQ) and posted answers that I hope will be useful for all. With increasing human populations, and thus increasing numbers of people dealing with aquatic organisms or environments, I foresee higher numbers of people getting fish TB.

Please see my articles at Aquarticles.com for more detailed procedures to follow to get fish TB cured, and more information on fish TB. These articles are listed at the end of this article. Consult a doctor for treatment to obtain a cure.

Q... What causes fish TB?

Bacteria of the species Mycobacterium marinum. These bacteria also infect fish and can cause loss of fish. These bacteria can occur in fresh and marine waters in temperate or tropical areas of the world, and on areas wetted by those waters. The bacteria are slow-reproducing and resistant to treatment. There are probably several to many different strains (affecting fish, affecting frogs, etc., affecting humans, and in different environments) of Mycobacterium marinum throughout the world. Other species of Mycobacterium cause leprosy, human TB, and various other Mycobacterium-caused problems.

Q... What does fish TB do to my fish, etc?

Fish TB is sometimes called "wasting disease." After the bacteria invade the fish liver, liver dysfunction/failure results, then the fish cannot assimilate food they eat and "waste away" and eventually die.

"Some signs to look out for include: Lethargy, anorexia, fin and scale loss, exopthalmia, emaciation, skin inflamation and ulceration, edema, peritonitis and nodules in muscles that may deform the fish. Examinations usually reveal gray or white nodules in the liver, kidney, heart or spleen. There also may be skeletal deformities. Diagnosis is usually based on clinical signs and the presence of acid fast bacteria in tissue sections." http://www.fishyfarmacy.com/articles/mycobacteriosis.html

It also causes a systemic infection in a large number of poikilothermic animals (frogs, etc).

Q…What is the treatment for fish?

If fish are eating, add antibiotics to food.

Kanamycin + Vitamin B-6 for 30 days http://www.fishyfarmacy.com/fish_diseases/physical_changes.html

"If you are unlucky enough to have to treat TB, the infected fish should be placed in a separate treatment tank. 40 grams per gallon of streptomycin and isoniazid, each, should be added to the treatment tank. Treatment can be increased by adding streptomycin to food." http://www.suite101.com/article.cfm/aquariums/1770

If the fish are not eating, antibiotic injections for the internal bacteria may work. But if liver or kidney function are too far gone, death can occur.

Q... How can humans avoid getting infected?

1. Do not wade, swim, fish, work, etc., where the bacteria may occur. Especially if you have a recent or open wound. This includes doing (but not limited to) the following:

-----. Handle sick aquarium fish with care. Thoroughly wash after handling fish, or doing tank work.

----- Thoroughly wash after fishing, or cleaning fish.

----- Avoid injuries (falls, scrapes, punctures) in areas wetted (beaches, piers, jetties, parking lots, sea walls, boardwalks, etc.) by natural waters, including boat bottoms (when cleaning off fouling organisms, etc.). Have any injury resulting from scrapes on barnacles, etc., thoroughly cleaned of shell fragments, etc., before the wound is sealed.

----- Avoid rope/chain injuries to hands, etc. when pulling up an anchor or doing other boat work.

---- Avoid splinters from oars, paddles, net handles, fishing poles, etc.

2. If an injury occurs, make/let the wound bleed for a while to cleanse wound and possibly push the bacteria out of the wound before stopping bleeding, washing (best to use sterile water), treating, and protecting wound.

3. While fishing/swimming/wading/working on tanks, do NOT treat an injury with antiseptic and THEN go back to fishing, etc., and think you have killed off all the pathogenic bacteria that might enter your fresh wound. After the antiseptic has been WASHED away by getting back into water, MORE pathogenic bacteria can ENTER the wound that has not yet healed over, and you can still get infected. Do NOT expose an unhealed wound to water that can potentially harbor pathogenic bacteria. Think of most waters as diluted sewage (and that's essentially what they are now inshore with all the aquatic animal wastes plus human sewage going into waterways) and realize you do not want to put an unhealed wound in such stuff. Use common sense; once you have treated the wound, do NOT put your unhealed body/body parts BACK into the suspect water and negate your previous wound treatment.

Since this bacterium is so difficult to treat, it is wise to obtain treatment quickly, and wiser still to try to avoid being infected (especially if you know you have a weakened immune system).

Q... How do I know if I have a weakened immune system?

If you are (1) young or old, (2) been recently sick or had a bad injury or are physically run-down, (3) have cancer, AIDS, diabetes, kidney disease, liver disease, hepatitis, or any other major disease, etc., (4) have undergone chemotherapy, radiation therapy, etc., (5) or have allergies/reactions to several natural or man-made substances, then you can suspect you have a weakened immune system.

Q... I've exposed myself to tank water (natural waters) and may or may not have wounds where fish TB bacteria can enter….what are my worries?

It depends on strength of your immune system (each person will be affected differently, if at all), if you exposed a point of entry (wound, opening, etc.), and if the bacteria are present in the water to infect you. If your immune system is strong, and not weakened by diabetes, HIV/AIDS, kidney disease, cancer, cancer treatment, liver dysfunction, old age, or any other body disease, injury, or dysfunction that weakens your immune system, you may not get infected if exposed. Generally speaking, the more compromised the immune system is the more dangerous the infection can be. If you have a weakened immune system, a Mycobacterium marinum infection may occur. Be observant of any reddened, irritated, itchy, skin granuloma (nodule) area, or lesion, and monitor any infection. If an infection starts and persists, or gets worse, see a doctor.

Q…I splashed (or siphoned water) into my mouth/eye. What are my worries?

Might be possible you can get a digestive pathogen, like Salmonella, Giardia, Shigella, or other species from any tank water ingested. There are previous reports of Mycobacterium marinum infections of mouth/throat from siphoning fish tanks.

Watch for initial signs an infection has started and obvious signs of a worsening infection on your face/nose/eye (where tank water hit). If there are no infection signs in 3-4 weeks, one can assume there is not a fish TB problem.

If an infection starts and persists, or gets worse, see a doctor.

Q…What are the signs of fish TB in humans?

Small granulomas under skin usually appear 2-3 weeks after exposure, then raised bump (nodule) at infection site, with skin turning into a red/pink to purple color, and being swollen, tender, painful, itchy, resistant to normal antibiotic treatment, nodule can change to a hard-to-heal, persistent lesion. Swelling of nearby lymph nodes can occur. Nodules/lesions can spread from initial infection site. (See various pictures of infections on the internet.)

Q... How is fish TB diagnosed in humans?

Via bacterial culture on special media, which can take two weeks or longer.

(1) "Culture of lesion aspirate on Lowenstein-Jensen medium, incubated at 30 C, showing light-induced (photochromogenic) yellow-pigmented colonies." (2) "Ziehl-Neelsen stain of lesion scrapings showing acid-fast beaded bacilli." (3) "Ziehl-Neelsen stain of water from the patient's fish tank showing numerous acid-fast bacilli." http://www.mssm.edu/medicine/infectious-disease/consultative/case_11.html

By DNA analysis.

Q…What human body parts can get infected?

Skin (especially of extremities: fingers, back of hand, elbows, knees, etc.), extremity joints (especially those of hand), eyes, throat, bones. Those parts having a lower temperature than the body core. Mycobacterium marinum grows best at an optimal temperature of 33 degrees C (91.4 F).

Q…How can I get a quick cure?

1. IF the infection has just recently become visible (small granulomas seen), and IF the bacteria have not yet infected deeper tissues than skin, then a quick cure (killing the bacteria in shallow infections) can be effected by medical doctors via various methods. Contact a medical doctor familiar with the infection.

2. IF the bacteria have gone undiagnosed/unnoticed/neglected until infection has either extensively spread on skin or into deeper tissues, then a quick cure may not be effected, except by cutting the infected tissue out, or off. A long course of antibiotics which have been ascertained to be effective against your strain of fish TB will probably have to be undertaken. The longer you wait to get treatment, and the more extensively spread or deeper an infection has gone, the longer the treatment generally takes to complete a cure.

3. IF you will follow the procedures for identification of M. marinum, and then get sensitivity tests done, you will find antibiotic(s) that will cure the strain in your body. These procedures are at: http://www.aquarticles.com/articles/management/Lawler_Tank_Safety.html

Q…Who can I find to treat me?

1. Check with your local aquarium clubs, aquaculture facilities, aquariums, aquatic laboratories, etc. to see if any local doctors have successfully treated fish TB on someone in your area. They might have treated the same fish TB strain you have if both of you got your infection from local waters, and thus can more successfully treat you. If you got your infection from imported fish in the aquarium trade, you may have a strain from across the world that will require different antibiotic treatments/combinations than local strains of the disease.

2. Find a dermatologist/doctor with previous experience in treating Fish TB.

3. Find a doctor who has either treated fish TB or other Mycobacterium infections (lung TB, leprosy, etc.).

4. Find a young, dedicated doctor who is not afraid of a challenge, or wants to learn about fish TB.

Q…Can I get a complete cure?

Antibiotics used in treatment of human lung TB are among those used to treat Mycobacterium marinum infections. See a doctor to get antibiotic treatment. Antibiotics effective against the strain of fish TB in your body may take a year or more to cure the infection.

IF the bacteria have NOT gone into a joint, or too deep into flesh, then a cure can usually be effected via oral antibiotics. Deep-seated infections may require surgery and/or irrigation with antibiotics and/or IV antibiotic drip in addition to the initial oral antibiotics in order to get the infection cured.

Q... How long does a cure take?

The effectiveness of a cure depends on many factors: how extensive your infection is, whether it is in deeper tissues or joints, if correct antibiotics were ascertained initially by doing sensitivity tests, if the antibiotics can be gotten to the infection bacteria, if you can tolerate the antibiotics recommended, other concurrent health/age problems or diseases, etc., etc.

A minor skin infection may take 3 months or so to cure. An advanced deep tissue or joint infection may take 6 months to a year or more of antibiotic treatment to cure. Apparent cures may not be so, and infections can flare up again, sometimes in deeper tissues or joints. A fungal treatment may also be necessary after the antibiotic treatment has killed good bacteria from mouth to anus in the digestive tract, etc., and secondary fungal infections have occurred.

Q…How serious an infection can I get?

There is a rare case of a disseminating (widespread) disease seen in immuno-compromised people that can be fatal.

Q…Can I get infected again?

If your immune system cannot stop the infection, yes. One person that worked on an aquaculture farm got it 3 times within a short period (about two years).

Beware of fungal infections after antibiotic use.

Q…What happens if I stop taking the antibiotic too soon because of adverse reaction or complications?

You will have made your body's strain of Mycobacterium marinum stronger, i.e., those bacteria that survived the shortened antibiotic treatment and reproduced will be more resistant to further treatment with the same antibiotic. So you will have to use a stronger dosage of your initially used antibiotic, or use a different antibiotic in order to cure the infection. It is not wise to stop antibiotics too soon because the infection can restart and the bacteria can be more-resistant than before. If you get adverse reactions or complications from an antibiotic, take another antibiotic recommended for Mycobacterium marinum as soon as possible after stopping the initial antibiotic. It is the highest priority to cure this infection to avoid long-term problems.

See these articles also for more information:

A Few Comments on Mycobacterium marinum … http://www.aquarticles.com/articles/management/Lawler_Diseases_Mycobacterium_marinum_fish_tuberculosis.html

Diseases Transmitted to Humans … http://www.aquarticles.com/articles/management/Lawler_Diseases%20Transmitted%20to%20Humans.html

Fish Tank Aerosols Transmitting Infections to Other Tanks or Humans … http://www.aquarticles.com/articles/management/Lawler_Aerosols.html

Some Infection Details of Aquatic/Fish Tank Infections … http://aquarticles.com/articles/management/Lawler_Infection_Details.html

Tank Safety/Fish TB ...
http://www.aquarticles.com/articles/management/Lawler_Tank_Safety.html

Touch Tanks …
http://aquarticles.com/articles/management/Lawler_Touch_Tanks.html

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