Epidemiology is a lot like detective work, and an outbreak going on in Hawaii right now has been a challenging case to crack.
Over the past couple of weeks, the Hawaii Department of Health (DOH) has identified 52 confirmed cases of hepatitis A virus (HAV) on the island of Oahu. Symptoms of HAV include a fever, loss of appetite, abdominal discomfort, dark urine, diarrhea, and a yellowing of the skin and eyes (jaundice). Sixteen of those cases have required hospitalization, and since most people with the virus recover without lasting complications, hopefully these people will also.
So far, all of the cases have been adults on Oahu (though this author wishes to point out that HAV infection in children is often less obvious, and over 70% of HAV infections in children under six are asymptomatic).
Two of the cases are employed in food service, with the first being an employee at a Baskin-Robbins in Waikele identified on July 12, and the other an employee at a Taco Bell in Waipio, identified a couple of days layer on July 15. The Hawaii Department of Health is encouraging people who consumed food or drink from the Baskin-Robbins on specific dates from June 17-July 3rd and dates between June 16-July 11 for the Taco Bell to speak with their healthcare providers about possible exposure to the virus. If these people were exposed less than two weeks ago, receiving the vaccine (or immune globulin, depending on the circumstance), may provide some protection against the disease.
It is important to note that these two restaurants are not being considered as sources of the outbreak, and that the likelihood of patrons acquiring the virus from these establishments is believed to be small. While people who work in food service establishments are not at a higher risk of contracting HAV because of their work, when they do become infected, they may impact large numbers of people simply because they interact with large numbers of people. In response, some restaurants on the island have taken added precautions of having employees wear gloves when preparing food, and instituted more thorough handwashing practices, with local food safety professionals suggesting these employees receive the vaccine.
The State Epidemiologist is encouraging all residents to consider talking to their healthcare provider about getting vaccinated, and for those with symptoms of hepatitis A to stay home and contact their healthcare provider.
Two of the interesting things about this outbreak is that the cases have been spread around the island, and yet there have not been cases on other islands. It is thought the source of the virus may be contaminated food or drink that is being served solely on Oahu. Earlier in the outbreak, news reports and people on social media were suggesting raw ahi (tuna) being eaten as poke (a salad-style dish made of cubes of raw fish) to be a possible connection. The state’s DOH is investigating the dish, but they are also considering a number of other possibilities. Since the cases are scattered and the incubation period (the time from infection with the virus to showing symptoms) can be a month or more, identifying a specific food or location of infection has been a challenge, and this tuna may be in fact a red herring. Case in point, can you accurately recall what you ate this time last week?
The Hawaii DOH has been interviewing those who are sick to identify potential sources of the virus, and have contacted the CDC and FDA for help with the investigation. The Hawaii DOH has also been providing regular updates on the outbreak investigation on their website and posted information on the virus for residents who are sick or may have been exposed. Since the virus can be transmitted through direct contact, the DOH has also been reaching out to household members and people close to the confirmed cases to prevent them from also becoming infected. Lastly, the DOH has also requested a coordinated effort with healthcare providers on the island to quickly identify and interview new cases.
We will post updates on this story as they come.