An excerpt from a boating forum concerning the effects of scratches from barnacles while cleaning his prop and shaft - submitted by Mike Bernard

Just A Scratch
By Norm Poulsen

I've been boating on the Chesapeake Bay for about as long as I have been a family physician -25 years. And nearly all of my encounters with the Bay, have been enjoyable. That changed on a fine August day a few years ago, when I had a brush with a strain of bacteria that researchers suspect are a threat to the Bay’s rockfish population. Luckily the bacteria is less dangerous to humans because we can seek treatment while the rockfish cannot. My wife Chris and I anchored our boat in Eagle Cove at the northern end of Gibson Island on the Magothy River, planning to relax a bit, eat dinner and then head back to the dock. But first, I was going to go down under the boat to clean up the prop and shaft of those pesky barnacles and other marine crud/ growth that I knew were growing on there.

I put on my diving mask and leather gloves. I gathered up my putty knife and a scotch brite pad. As I climbed down the swim ladder, I never gave it a thought that this simple routine activity would affect me for the next several months.

After the usual six dives just to clean the prop, I went down to tackle the shaft. While scraping it off, I lightly brushed my bare arm against a couple of barnacles, that were still clinging to the strut. When I surfaced, I checked my arm and found two very faint scratches, with almost no bleeding so I didn’t pay too much attention to it. I went back down to continue cleaning the shaft. When I climbed back on board, I thoroughly washed the scratches with dish detergent and squeezed on Neosporin ointment on them. This was hardly the first time I’d had a cut exposed to Bay water and I never suffered any long term effects as a result. But being a victim of knowing a little too much, I wondered at the time if I might come down with an infection on my arm.

I was concerned about two very different bacteria. One can be very aggressive and progress rapidly to a serious systematic infection and even death of not treated quickly. Even the name sounds bad: Vibrio vulnificus. It is found in up to 80 percent of Bay water samples taken during the warm months , and it grows rapidly. It causes nausea, vomiting and diarrhea if sufficient amounts are ingested with raw seafood—-especially oysters and it can cause rapidly developing skin infections in wounds exposed to contaminated water. Most infections are mild, but even they can also lead to tissue destruction and large blister formation. In higher-risk individuals—-people with liver disease or depressed immune systems, as well as chronic diseases like diabetes, or rheumatoid arthritis—severe infections, sepsis and shock are possible with death rates of approximately 50%. Luckily, significant infections are rare. Awareness and prompt treatment of possible infections are t he best prevention of serious problems. High risk individuals should avoid exposing wounds to sea water and might want to avoid eating shell fish—-(although there have been no recorded instances of illness from ingested vibrio from shellfish harvested from the Chesapeake Bay. )

Because I am not in a high risk group I was not too worried about Vibrio. And when I didn’t get sick and die within a few days after the incident happened, I knew I was pretty much in the clear for coming down with Vibrio. The second type of infection that did cross my mind right after the light scatch took place on my arm was, Mycobacterium marinum, . It is a very slow growing bacteria and is a close cousin to the bacteria that cause tuberculosis. Mycobacterium marinum grows in fresh water, salt water, brackish water…….even in fish tanks. The infection that it causes among humans is know as “Fish Handlers disease” or “Fish-Tank-Finger”. It grows best at 82 to 90 degrees Fahrenheit. When the scratches on my arm healed quickly and my arm looked fine, I felt relieved that I had escaped without any problems.

Two weeks later, however, I noticed a small reddish-purple bump developing where the scratches had been located. Exercising my excellent capacity for denial, I was able to ignore it. Over the next few weeks, more bumps developed. Although the entire area involved was only about an inch in size, it didn’t hurt much and it didn’t itch. It was still easy to dismiss as insignificant. But then I noticed a tender, swollen lymph node just above my elbow and a few of the bumps were starting to drain. I could no longer persuade myself that this was ’nothing’.

I called my own primary care physician and spoke to the receptionist. I told her that I believed that I had a Mycobacterium marinum infection in my arm. After a moment’s silence, she said “I am going to have the nurse talk to you”. I told the same thing to the nurse. And after the same moment’s silence, she told me that I had to come right in. I replied that I had had the infection for a few weeks already and asked if they had an appointment for next Monday? When I finally saw my doctor, he took my word for it, as to what I had. He cultured the drainage and started me on clarithromycin (Biaxin). After 10 weeks of being on antibiotics, the lesions were smaller and fading but still present. Meanwhile, 5 weeks after my initial doctor visit, I received a call that the culture for Mycobacterium was positive, although it still had not been identified as to which type.

According to medical literature, Mycobacterium marinum infections are quite rare and many physicians even in the Chesapeake Bay region are not aware of this type of infection. Since I contracted mine, I have learned of a few of my boating friends having the same experience of being scraped by barnacles. One guy didn’t treat at all, and it cleared up on it’s own after about 18 months. Two others took antibiotics for 4 months to get it to go away. One needed surgery and nine months of antibiotic treatment. They were all the result of infections from cuts or abrasions that occurred underwater. None of the infections were due to cuts that were later exposed to Bay water.

I have read of a number of cases in medical literature about patients who underwent multiple cultures and biopsies to try to diagnose the infection. This all resulted in a delay of proper treatment. These bacteria do not like humans’ normal 98 degree core body temp—-which makes it less of a threat, because the infection stays confined to the cooler extremities and does not become systemic. But that same characteristic makes it difficult to identify in a lab where most bacterial cultures are grown at body temps. Lab Corp, one of the nation’s largest medical laboratories, wasn’t quite sure what to do with the specimen from my arm, that we sent in. An ordinary wound culture, which is usually complete in a few days, would have been reported as negative after no bacteria grew from the sample. Once a physician is familiar with these infections, however a culture is not always needed to make a diagnosis. Just because the infection is slow growing does not mean that it is harmless. If it gets into the joints or tendons, especially the fingers, it can be destructive and may need surgical incision in addition to antibiotics. Antibiotic therapy is lengthy and several different treatments are available. It appears that the one I took (Biaxin) is the most widely used, but sometimes several medications must be prescribed simultaneously, including rifampin and ethambutol, two drugs usually reserved to treat tuberculosis. A Mycobacterium marinum will often turn up a positive result on a PPD skin test, which is also used to diagnose exposure to TB. My test result turned up positive for TB, and had I not known the reason, I would have had to take 6 to 9 months of treatment with an anti-TB drug, isoniazid . Ironically, isoniazid does not treat Mycobacterium marinum and it would not have helped my infection.

So if you get a cut while you are in contact with any kind of sea water, that initially heals but the site develops a nonpainful, non-itchy reddish-purple rash in it’s place, don’t ignore it. Go to your doctor, armed now, with a little bit of knowledge. The best prevention is to avoid getting a cut while under water, and avoid having your skin coming in contact with barnacles. Wear gloves and a heavy shirt when cleaning bottoms and don’t touch barnacle covered pilings with bare feet!