Observation: I contracted a case of Vibrio parahaemolyticus (Vp) gastroenteritis (marine cholera) after consuming raw Alaska oysters at a local restaurant. This incident was followed up by the State Health Department since this is a food-borne illness. The most pronounced symptoms were severe abdominal cramping, diarrhea, and exhaustion for 12 days. After antibiotics and probiotics, a milder form of symptoms still persists 3 weeks later. This is really an awful illness and I hope no one else contracted it from this event.
I understand the last Alaska outbreak was in 2004 when passengers on a cruise ship consumed Prince William Sound oysters and fell ill. These were also confirmed cases of Vp. I know that Vp is related to water temperature. Both 2004 and 2016 were warm years for ocean temperatures. I wonder if there has been a trend related to water temperature and any affects this bacteria could be having on marine mammals such as sea otters. I am also wondering how we might prevent other people in Alaska from getting this illness in the future.
Observers note: The views expressed here are intended to share a personal experience, and the author’s content does not represent EPA’s views or policies.
LEO says: Thank you Santina for sharing your story. Vibrio parahaemolyticus (Vp) is a bacterium that lives in seawater and thrives when water temperatures exceed 62 degrees Fahrenheit (16.6 degrees Celsius). Due to warming sea temperatures, conditions that can support vibrio have begun to occur in Alaska. People usually get exposed when they eat raw oysters or other types of shellfish.
The first recorded incident of locally-acquired human infection with Vp in Alaska was in July of 2004 when a cruise ship with 189 passengers was served oysters from a Prince William Sound oyster farm. Sixty-two of the passengers became ill. The surface water temperature from the farm was 62-63 degrees Fahrenheit. The event described in a 2005 paper published in the New England Journal of Medicine expanded the range of Vp illness more than 1000 km further north than ever recorded before. The authors recommend, "when water temperatures at oyster farms exceed 15.0°C, control measures should be considered, including the establishment of a monitoring program for tdh-positive Vp, the moving of oyster nets into cooler waters, the implementation of post-harvest processing of oysters, and the issuance of public advisories to cook oysters." Note: TDH is a genetic factor that codes for greater virulence of this bacteria.
There are inherent risks associated with consuming raw shellfish, which can be reduced but not necessarily eliminated. Shellfish producers reduce the risk by keeping their product in colder water. Consumers can reduce their risk (from bacterial infections) by eating cooked shellfish and being selective about the season when oysters are consumed. The warm season is usually the higher risk season. It is important for consumers of raw shellfish to consult a provider at the onset of abdominal pain, nausea, vomiting and/or diarrhea. For more health information see the State of Alaska Department of Health and Social Services Epidemiology Bulletins. For information about coastal water temperatures see NOAA's Alaska Coastal Water Temperature Table. This observation has been shared with the State of Alaska Department of Health and Social Services DHSS, as well as the Alaska Department of Environmental Conservation (ADEC).
According to Dr. Louisa Castrodale with DHSS, "cases of human vibriosis, including V. parahaemolyticus, vulnificus, cholerae O1 and non-O1 types, are reportable to the Alaska DHSS, Section of Epidemiology (SOE) by health care providers and laboratories. Each suspected case is investigated to ascertain potential exposures to the bacteria. For Vp, consumption of seafood is a main risk factor for illness; therefore, investigators seek to determine the source of seafood or shellfish, as well as other risk factors, such as travel or different exposures to salt water and a marine environment. When seafood or shellfish consumption is confirmed, SOE collaborates with DEC to trace the source of the seafood whether harvested in Alaska or outside of the state."
As to questions about ocean conditions during the time of this event, temperature varies by location, time of day and depth. However, environmental data on surface water temperatures can be informative about the potential range that could support Vp.
UAF Arctic Research Center Consult: Dr. Soumik Basu with UAF's International Arctic Research Center has reviewed sea surface temperature records from the NCEP Reanalysis data (NOAA Extended Reconstructed Sea Surface Temperature (SST) V4). He writes: " If we look at the 10 years (2005-2016) long-term monthly means for June-September, the spatial distribution of Sea surface temperature shows that the sea surface is warmest in June-July-August (First figure). The warm waters along Alaska's coast then shift further south in September, reducing the chances of vibriosis cases in Alaska (Please take a look at the figure showing variability of the threshold value). Thus it can be said that the anomalous warm water during the summer months of June-July-August along the coastal south Alaska increases the chances of contraction of vibriosis. The sea surface temperature reaches the threshold value of 10 degree C along coastal south Alaska and this warmer surface water shifts southwards in September, lowering the potential of contracting vibriosis by consuming raw sea food."
Nature Climate Change – Emerging Vibrio risk at high latitudes in response to ocean warming. "There is increasing concern regarding the role of climate change in driving bacterial waterborne infectious diseases." Baker-Austin C., et al. June 27, 2016.
Alaska Sea Grant, University of Alaska Fairbanks, Vibrio parahaemolyticus, a Climate Change Indicator in Alaska Marine Mammals. in Responses of Arctic Marine Ecosystems to Climate Change, Alaska Sea Grant. Anchorage, Alaska. — Vibrio parahaemolyticus (Vp) is considered to be an indicator of climate change because it proliferates only in waters with sustained temperatures higher than 59°F (15°C), which are unusual in the north. Increasing water temperature and decreased salinity of coastal areas, events associated with global climate change, are important factors in the proliferation of many bacterially mediated waterborne diseases, contributing to a worldwide increase in disease events and the emergence of these diseases in new, more northerly areas.
Centers for Disease Control and Prevention, Vibrio Species Causing Vibriosis — The Vibrio species that cause vibriosis naturally live in brackish or salt water. Information on this website focuses on Vibrio species causing vibriosis.
State of Alaska Department of Environmental Conservation (ADEC), Vibrio parahaemolyticus Control Plan — Describes actions ADEC and oyster –harvesting and shipping operations must take to reduce the probability of occurrence of Vp illnesses during periods that have been historically associated with vibriosis in the state. This plan applies to all oyster growing operations throughout the state from June 15 through September 15, 2016.
Photo: An indicator of healthy marine environments¹ — Did you know sea otters are indicators of the health of the overall marine environment? They live and feed along shorelines, making them a good indicator species for detecting pollutants and pathogens washed down from coastlands. And along many parts of Pacific North America, sea otters play critical roles in natural food webs, keeping important ecosystems like kelp forests and seagrass beds in balance. (Photo courtesy of Ron Eby) Source: Pacific Southwest Region USFWS