Pathogens capable of inciting disease pandemics are a major global worry. Just look at human concerns about antibiotic abuse and the occurrence of MRSA. Look at recent worries about Ebola outbreaks. Even look at the return of diseases that could easily be prevented in humans, were people not so blinkered and scientifically ill informed about vaccines. Disease pandemics are a major fear.
If you’re a newcomer to the hobby, then whatever you think you know about fish farming – forget it. If you have images of clinical facilities where each and every fish is treated like a newborn infant, then it’s back to the drawing board time. Farms are businesses, plain and simple. The goal is to get young fish out of adults as eggs, to hatch them, and to get them up to saleable juveniles as soon as possible, and that means that pretty much anything is on the cards to get them there. Antibiotics are used where necessary (and maybe even where not), and not just the kinds of antibiotics that you or I might have access to via a vet. Different countries have different laws about what can and can’t be used, and in some it’s a bit of a medicine free for all.
Hopefully we all know the dangers of antibiotic abuse, but in case anyone is unsure, here’s a brief recap:
Antibiotics kill things indiscriminately (the very word 'antibiotic' literally translates as ‘against life’). The idea is that they kill bacteria at a lower dose rate than which they kill the host. So if a fish gets ill, you can poison everything in the tank with antibiotics, and the pathogens making the fish ill should die before the fish does, and then you can stop the antibiotics.
However, if you leave a few bacteria behind, they start to get immune, and can build tolerance to the antibiotic. So, the next outbreak of bacteria will be a bit 'harder' to control than the first lot. Repeat the process, leave a few bacteria behind, and they get harder to kill again, until eventually you end up with pathogens that are so resistant to antibiotics that you’d need to use a dose rate so high that you’d kill the host before the pathogen.
That’s the abridged version, anyway.
The problem of course is that unregulated use of antibiotics over in the farming nations could quite feasibly create a strain of bacteria that our own antibiotics have no effect against. With diseased fish coming in, and no ability to cure them, we wouldn’t stand a chance.
But it’s not just bacteria.
There are a few pathogens on the horizon that are cause for concern at this time. In coldwater fish, there are the dreaded illnesses of KHV (Koi herpes virus) and SVC (Spring viraemia of Carp), both of which have the potential to cause massive problems to Cyprinids. Not so long ago, massive wipeouts from the former blighted farms across the world, causing losses on unmentionable scales in both ornamental and food fish culture. Here in the UK, some retailers faced the furious backlash from introducing the disease to consumer’s ponds. One was even driven to bankruptcy over it.
In the tropical world, I am very twitchy about Tetrahymena pyriformis, otherwise known as Guppy disease (though this is unfair as many fish are susceptible). This disease can cause massive mortality at breakneck speeds, especially in farm, wholesale and retail environments. I’m not the only one worried about this particular pathogen, either.
What is so very infuriating is the ‘wait and see’ attitude of some traders. This is not a disease to ignore, and to do so is not just at your own peril, but that of the entire industry.