By James Peacock

A report filed by the Hawaii State Department of Health on November 7, 2016 indicates that they are investigating another outbreak, this time involving Salmonella, on the island of Oahu. There are currently 14 cases of Salmonellosis, the illness caused by Salmonella bacteria, linked to the outbreak. These illnesses have occurred in both children and adults. Four of those sickened required hospitalization, and there have been no reports of death. The illnesses caused by this outbreak began in mid to late October. Investigations by local and state health officials have led to the identification of raw fish that contains seaweed as the potential source of the outbreak. It is important to keep in mind that health officials have not confirmed this seaweed as a source of the outbreak, but the evidence makes the contaminated seaweed a likely culprit. The seaweed involved in the outbreak was one of the only common ingredients across many of the cases of illness. The investigation into the Salmonella infections is ongoing, so there may be more information, or more cases of illness, added at a later date.

The potentially contaminated seaweed came from a farm on Oahu called Olokai Hawaii. The owner of the seaweed farm has said that this is the first issue with the farm in over 10 years of operation. The owner also suspects the water used in the aquaponic systems may be to blame for the contamination. The farm has been told to stop operations immediately, and the products from the farm have been pulled from shelves.

            The State Epidemiologist, Sarah Parks, released a statement along with the outbreak announcement, saying “Although our investigation is still ongoing, our preliminary investigation has implicated “limu”, also known as “ogo” or seaweed, produced at a particular farm on Oahu. To protect the public’s health, the department stepped in to make sure this product is no longer being sold on the market pending further investigation. At the same time, we want the public to be aware of the situation so they may seek medical care if needed.”

            The consumption of raw seafood has recently been a problem for Hawaii. Over the last few months, there have been a large amount of illnesses caused by Hepatitis A on various islands in the state. That outbreak, which has now sickened close to 300 people, was linked to raw scallops that were imported to the islands from the Philippines. However, the amount of new illnesses added to the Hepatitis A outbreak has decreased dramatically over the last few weeks, and the outbreak appears to be on the brink of being over. Health officials have made it clear that raw foods should not be consumed, due to the risk of infection. Instead, Person preparing raw seafood should make sure that the internal temperature of 160 degrees Fahrenheit is reached to ensure that all bacteria are eliminated.

Salmonella infections continue to be one of the most common forms of foodborne illness in the United States. Although they knew of its existence for some time, Salmonella began to be tracked in 1962. Dr. Salmon first discovered the bacteria and its effects more than 125 years ago. Since the tracking of Salmonella bacteria began, health officials have identified a series of serotypes, or strains, of bacteria. Each strain is still considered to be Salmonella, but the DNA it contains or the effects that it has on humans may differ slightly from other forms of the bacteria. There are many different strains of Salmonella bacteria, but all will cause illness in humans.

The 32 different serotypes of Salmonella bacteria help investigators pinpoint potential outbreaks, as well as their sources. When the number of infections reported increases rapidly and suddenly, it is an indicator to health officials that an outbreak is taking place. Health officials can then investigate the outbreak. Outbreak investigations tend to follow two strategies, taking samples and conducting interviews. When interviews are conducted, there is sometimes a correlation between the answers given, which can help investigators locate a source of the outbreak. In this outbreak, investigators discovered that raw fish, specifically raw fish containing raw seaweed, was a common food item amongst those who were sickened in the outbreak.

Although interviews can help locate potential sources, the best way for health officials to learn more about an outbreak is through the testing of samples. When medical providers retrieve samples from ill people or from the environment, the samples undergo testing to learn more about them. This type of testing reveals is the bacteria’s DNA fingerprint. This fingerprint, which is the product of pulsed field gel electrophoresis (PFGE), is unique to the bacteria and strain involved in the outbreak. Investigators also use Whole Genome Sequencing (WGS), to get a more detailed view of the DNA in a bacterial sample. The DNA fingerprint and genome is then uploaded to the PulseNet system. The PulseNet system is a database of DNA fingerprints maintained by the CDC. If a saved sample matches another sample, there may be a connection between the two. When multiple samples match through the PulseNet system, it is another clue to investigators about the origin and size of the outbreak.

The Centers for Disease Control and Prevention estimates that Salmonella bacteria infects about 1.2 million people each year in the United States. There are an estimated 450 deaths caused by Salmonella infections. Salmonella infections lead to the hospitalization of about 19,000 people each year. Typically, a case of Salmonella poisoning will generally produce symptoms within 12 and 72 hours after infection. Salmonella infections will most often produce symptoms including vomiting, fever, abdominal cramping, and nausea. While a Salmonella infection will likely subside on its own within a week, there is a chance that the illness may worsen or cause severe dehydration. This may make hospitalization necessary. Those with certain risk factors, including the elderly, children, and those with suppressed immune systems may be at an increased risk of developing a serious Salmonella infection. If you or a loved one begin to show the symptoms of Salmonella poisoning, contact a medical professional.

 

Sources:

https://health.hawaii.gov/news/files/2013/05/16-077-Salmonella-Infection-in-14-People-on-Oahu-Linked-to-Poke-1.pdf

http://www.hawaiinewsnow.com/story/33652990/doh-tainted-limu-suspected-in-14-cases-of-salmonella-on-oahu

https://www.cdc.gov/salmonella/index.html