Human skin infection caused by keeping tropical fish aquaria. Say it ain't so!

[bekateen]

Li, J., Chong, A.H., O’Keefe, R., & Johnson, PDR. 2014. The fish tank strikes again: Metachronous nontuberculous mycobacterial skin infection in an immunosuppressed host. Australasian Journal of Dermatology (2014) 55, e77–e79

ABSTRACT
An 82-year-old woman on long-term prednisolone for chronic obstructive airways disease presented with a 2-month history of nodules on her left forearm. This occurred 10 years after nodules on her right forearm caused by a culture-proven Mycobacterium marinum infection. Histopathological examination, polymerase chain reaction and culture of biopsy specimens were positive for M. chelonae. To our knowledge this is the first case of metachronous nontuberculous mycobacterial skin infection reported, and it highlights the diagnostic and therapeutic challenges of such infections.

This is a rare infection in humans, and it probably wouldn't have occurred if the woman wasn't taking an immunosuppressing drug. So what's the take-home lesson? That these drugs are becoming more widely-used in the general population, and thus for all of us who use steroidal anti-inflammatories chronically (for management of such things as asthma, arthritis, severe allergies, skin conditions like psoriasis, eye problems, etc.), be mindful of any skin rashes you develop after reaching into your tanks, if the rashes don't go away over time.
Cheers, and happy fish-keeping!

[Bas Pels]

I think it was 5 years back when a veterinarian ended his presentation about fish diseases with a few pictures of human hands, with nasty wounds. The wounds came from keeping fishes.

I think we should try to keep our hands as much as possible out of the tank - better for the fish and ourselves, and when we have done something in a tank, always rinse the arm with clean water. This will help keeping any disease isolated in only 1 tank, but it will be better for ourselves too.

Once I had a problem in a tank, fishes could turn in a few hours from seemingly alright to a stinking corpse, stinking as if it was dead for a few days. During the disease I did not go into the tank, I removed the corpses with a dedicated net, which was disposed afterwards, and then I let the whole stand for a fortnight in order to give the diseases time to die off. Only then I started cleaning the interior, which took a while, and the cleaned tank has been standing there for weeks empty.

When I filled it, no fish got ill, and I myself have not had any problem either. But boy I was both careful and scared

[Jools]

I've seen this in a guy I worked with in a fish store. Don't think it's at all common.

Jools

[TwoTankAmin]

The potential for this disease moving from a fish to a person is pretty uncommon. While we are looking at the hobby, the statistics cover everybody who works with fish. Included would be fishermen, people who work in zoos or public aqauriums, people who work processing fish, farming fish and pretty much any profession that brings one into regular contact with fish.

This is from an article on the subject by Neil Hepworth published in Practical Fishkeeping:

Infection rates in people are low. In the USofA, where they seem to get it a bit more than in the UK, the rate (for all cases, not just aquaria) is around 0.27 infections per 100,000 population. In the UK, the current rate of murder is 1.22 per 100,000 population. So, you’re likelier to be killed by a loon with a machine gun than catch it. It’s pretty rare.

http://www.practicalfishkeeping.co.uk/c ... p?sid=6079

Consider this:

The odds of becoming a lightning victim in the U.S. in any one year is 1 in 700,000. The odds of being struck in your lifetime is 1 in 3,000.

http://news.nationalgeographic.com/news ... facts.html

[bekateen]

Don't think it's at all common.

The potential for this disease moving from a fish to a person is pretty uncommon.

Yes, it is pretty rare. IMO, one point of the article was that this particular person was a long-time user of an immunosuppressing drug, prednisone, which she had been using to manage a respiratory problem (COPD). What made this woman more unique (and interesting from a medical perspective) was that she had two different mycobacterial infections at the same time.

A person with a normal immune system probably wouldn't have gotten the infection. But steroidal immunosuppressants are being prescribed more and more as their value in helping treat a variety of medical conditions is being accepted; with more people using these drugs, the risk factor for this type of infection increases significantly.

Interestingly, one of the bacteria involved in this infection, the one associated with the aquarium hobby, appears to be more common in certain parts of Australia than in other parts of the world:

Cutaneous NTM infections are uncommon and a high index of suspicion is required for diagnosis. Risk factors include immunosuppression, trauma and occupational or recreational exposures. An exception to this pattern is the emergence of M. ulcerans infections (Buruli ulcer) in coastal Victoria and far north Queensland. Buruli ulcer can occur in normal hosts of any age and there is usually no history of antecedent trauma. In Victoria the current incidence of this aggressive mycobacterial skin infection is 1.3/100 000 per year but the disease is geographically focal and incidence can be more than 100 times higher in specific locations.(Emphasis mine)

This is about 400x higher than the rate you found, TTA, for the entire tropical fish industry in the USA, and still about 100x higher than being murdered. I suppose our friends down under need to be a little more careful than the rest of the world.

BTW, I wasn't trying to scare or panic anyone. Not saying we're all gonna die... (well, we are, but not from this, and God willing, no time soon). I just found this to be an interesting report.