Thursday, August 14, 2014

Be Afraid -Though It’s Not Flesh Eating Bacteria

Local headlines this summer have reported that 6 cases of “flesh eating” bacterial infections have been reported from swimmers in the Chesapeake Bay watershed in Maryland and Washington DC. These are not the true necrotizing fasciitis (flesh eating) caused by group A streptococcus, they’re worse. These are cases of infection with the vibrio vulnificus bacteria. The difference is that in necrotizing fasciitis the A streptococcus attack the bands of tissue that surround muscles, nerves, fat and blood vessels. Vibrio vulnificus, on the other hand, gets into the blood stream from either a cut or skin abrasion or through the intestinal tract, and can damage organs (especially the liver) and cause skin lesions, that can result in hospitalization, amputation and death. Vibrio vulnificus has a higher death rate than flesh eating bacteria.

Vibrio vulnificus is a bacterium in the same family as those that cause cholera . It normally lives in warm seawater and ocean estuaries because they require warmer waters and low to moderate salt levels. Most vibrio vulnificus infections reported to the Center for Disease Control and Prevention (CDC) have historically been from the Gulf Coast states, Alabama, Louisiana, Florida, Mississippi, and Texas; however Maryland and Virginia have reported increasing incidence of the infections since 1999. It is unclear if there has been an increase in the incidence of infections or better reporting. So far this year 4 infections have been reported in Texas, 13 in Florida, 6 in Maryland and 10 in Mississippi.

Typically, Maryland and Virginia report and average of 25-30 infections a year that occur primarily in in the warmer months of May to October. However, last year Maryland reported 57 cases. The CDC states that vibrio vulnificus infections are rare, on average there are 95 vibrio vulnificus cases each year, 85 require hospitalizations and 35 result in deaths. However, vibrio vulnificus is also under reported, only in 2007 did infections caused by vibrio vulnificus and other vibrio species became nationally notifiable.

In response to the public alarm the Chesapeake Bay Foundation (CBF) reissued its 2009 report that documented the rise in such infections. In this report they state: “Vibrio vulnificus, which can cause severe skin ulcers, gangrene, and deadly blood infections in people who expose cuts to warm saltwater containing the bacteria, as well as gastrointestinal illnesses in people who eat tainted shellfish.”

Dr. Rita Colwell of University of Maryland and John Hopkins Bloomberg School of Public Health and her colleagues demonstrated that vibrio vulnificus, comma-shaped bacteria, are natural inhabitants of most of the world’s warm bays and oceans. Dr. Colwell “discovered that Vibrio is carried by microscopic, crab-like animals called copepods. These floating crustaceans—a form of zooplankton common in the Chesapeake Bay and elsewhere. Nutrient pollution stimulates the growth of algae, especially during warm-weather conditions. And algal blooms fuel the multiplication of copepods. Research has suggested that intense algal blooms have the potential to support “explosive growth” of Vibrio. When copepods die, Vibrio are shed into the water. And if the bacteria are in very dense concentrations, people can get sick if they drink the water or expose an open cut.”

From the Texas Department of Health and the CDC here are general recommendations for avoiding wound infections:
  • Do not handle raw seafood of any kind if you have a pre-existing wound, cuts, scrapes or scabs.
  • Wear gloves when handling raw seafood.
  • Avoid bay waters, estuary waters or brackish (sea/ocean) water if you have any pre-existing cuts scrapes, scabs or other wounds.
  • If you sustain a wound or injury while exposed to salty seawater or while handling seafood, thoroughly clean and disinfect the area immediately and seek medical attention if the area becomes inflamed. 
  • Prompt and immediate treatment is likely to have the most positive outcome. 
General recommendations for avoiding infection by consumption of live Vibrio bacteria
  • Only eat seafood or shellfish that has been thoroughly cooked until steaming hot.
  • Eat shellfish immediately after cooking and refrigerate leftovers.
  • Avoid cross contaminating raw juices from seafood with other foods, and immediately cleanup any spills with hot water and soap and clean rinsing water.
  • Keep raw seafood separate from other food.
  • Thoroughly wash hands, utensils and surfaces after preparing or handling raw seafood.

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