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Diary of an investigation in the Gulf Coast
The Pascagoula hepatitis outbreak of 1961 forged a path for national epidemic investigation and biological warfare preparation.
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This is the third EIStories, IDN’s series of articles about outbreak investigations conducted by CDC EIS officers.
In 1961, officials from the United States Navy noticed a hepatitis A outbreak in Pascagoula, Miss.
With sailors set to ship out on an extended tour in a nuclear submarine recently outfitted there, Navy officials asked the CDC’s Epidemic Intelligence Service epidemiology branch to investigate. A hepatitis outbreak aboard an extended naval deployment could jeopardize the mission. About 200 residents in the Mississippi coastal town and nearby areas were already stricken. One fatality may have been attributed in part to the outbreak.
James O. Mason, MD, DrPH, was working at EIS to fulfill his two-year military obligation when he was asked to investigate the Mississippi outbreak. It was his third outbreak investigation.
For Mason, this investigation around the Mississippi bayou would begin a career in public health spanning five decades, leading to his post as CDC director during the emergence of the AIDS epidemic and an invitation from President George H.W. Bush to serve as assistant secretary for health for the United States. In later years, Mason would serve as a public health director in Utah and on mission in Johannesburg, South Africa.
Looking back on the Pascagoula outbreak, Mason noted that although society has changed in ways that can be detrimental to the time sensitivity of disease spread, detective legwork for outbreak investigation is, in essence, the same now as it was 46 years ago.
“The mathematics behind it has become much more esoteric, but the shoe leather epidemiology of getting out there, talking to patients and getting into the community hasn’t changed,” Mason said in a recent interview with Infectious Disease News.
Mason arrives
Hepatitis A, formerly known as infectious hepatitis, is communicable, common and usually transmitted by polluted water or via the fecal–oral route of food and inadequate handwashing. A vaccine is available that can thwart infection for 15 to 30 years. It is usually transmitted from child to child, who then transmit the disease to adults through spread on common surfaces, such as doorknobs. The Pascagoula epidemic was unusual from the start because it was largely confined to the adult population.
When Mason first came to Pascagoula, he contacted local public health officials and physicians. He immediately headed to the hospital to interview patients.
“I thought that would be the easiest way to get to the largest amount of people in the shortest amount of time,” Mason said.
After quickly confirming the outbreak was infectious hepatitis, Mason started to rule out possible sources. It could not be the general water supply, because children and adults alike would be affected in greater numbers. In patient questioning, Mason soon found that a large number of patients had eaten raw oysters six to eight weeks before the onset.
Up to this point, there had never been a recorded association in the United States between shellfish consumption and hepatitis. Mason remained suspicious of raw oysters, but first he had to ensure that the consumption of raw oysters was not just common practice in Pascagoula.
To determine this theory, Mason made random calls from the 30-page phone book in his hotel room. “It would be hard to do this kind of interview today because of telemarketing,” he said.
Although he recognized his method was not scientific — people in homes without phones could not be reached, for example — Mason found that the interviewees’ answers matched his suspicions.
Mason asked people about various dietary habits. It became obvious that not everyone in Pascagoula ate raw oysters, but the rates of consumption among patients who ate raw oysters were significantly higher than the consumption of raw oysters by the population in general. “It wasn’t proof, but it was evidence,” Mason said.
It was also obvious that the source could not be oysters in general because there would have been more cases. Two days into the investigation, Mason had identified a source, but not the specific source. “It only took a couple of days to narrow it down to raw oysters; what took more time was to link the epidemic to a particular brand or source of raw oysters,” he said.
Packing plants investigated
Literally overnight, Mason had to become an expert in oysters, which were a rarity in his native Utah. Mason had to learn not only about oysters themselves, but about the commerce of the shellfish as well, including processing, tonging or harvesting, and marketing in grocery stores and restaurants.
A few cases in Mobile, Ala. helped Mason because they involved adults who had eaten at an oyster bar there. The oyster bar would lead to packers and maybe the suspect oysters.
“That led me to look at every bag of oysters at the oyster bar during that time. Pretty soon I found out a small supply came from Pascagoula,” Mason said.
Samples were sent to the CDC and to the state health department of Mississippi. If there were bacteria associated with fecal pollution, it would be an indication that fecal contamination was occurring and this would be found in the oysters. It was clear that only certain oysters were causing hepatitis, so public health warnings were issued, but delicately. “We wanted to alert the population, but not do in the industry,” Mason said.
The bags from the Mobile oyster bar were traced to a family in Pascagoula, which helped to unravel the whole mystery. The oysters responsible for the epidemic were tonged in closed waters at the mouth of the Pascagoula River. To handle unexpected and rapid population growth resulting from the Ingalls shipyard and nuclear submarine industry, the town developed a sewer system bypass, in effect dumping raw sewage into the waters and closing the waters to harvest.
“They were beautiful oysters because no one else was tonging them, and they were big because they were feeding on raw sewage and were growing well,” Mason said.
Ship captains were tonging in the closed, illegal waters for convenience. Most were taken at night by one family who had the whole illegal harvest to themselves.
“I doubt they had adequate patrols to make sure that people trying to make a buck weren’t going out there to get those wonderful, juicy large oysters,” Mason said.
Oysters filter everything that flows through them, so in customary whole oyster consumption, a consumer is sampling the growing waters.
The case was closed in Pascagoula in 11 days, but Mason still had work to do.
Investigation goes national
When Mason returned to Atlanta, he looked at patterns of hepatitis throughout the Eastern United States. It was immediately clear that other oysters and clams consumed throughout the country were coming from polluted waters.
Mason went to the famed Fulton Fish Market in New York City to search through bags of cherrystone clams suspected in another outbreak.
“I spent a lot of time sifting through oysters and clams coming through there,” he said.
He and colleagues nicknamed this type of hepatitis the “Outbreak of the Gray Flannel Suits” because of the fashion worn at the time by the uptown businessman most likely to consume raw oysters and contract hepatitis.
At the end of the investigation, the shellfish industry realized it needed to do a better job policing itself. Most shellfish consumed in the United States today are produced under standards borne of the 1961 investigation.
Societal trends
In his phone and hospital surveys, Mason asked people how often they ate at restaurants. As it did in the Pascagoula investigation, a restaurant lead can narrow down sources quickly. Not surprising for 1961, a large portion of participants reported they had not eaten in a restaurant in more than 50 days.
“People’s eating habits have changed. There weren’t that many restaurants and even so, most people didn’t have the money,” Mason said.
Another notable change in public habits was the ease with which he conducted telephone interviews and site investigations. “The interesting thing to me was how willing people were to talk to me on the phone and in person. There was an openness,” he said.
Even though people were participating in illegal activities and even though an outsider such as Mason was investigating in local bayous, people readily accepted Mason out of concern for public health during the outbreak. Even the family responsible for the outbreak was relatively forthcoming and was apologetic and concerned about people affected.
“People were more relaxed. Today people would have their lawyers. But at the time, I could go into an oyster bar and just open up their records without a subpoena or court action,” Mason said.
These factors made it easier to solve the case quickly and prevent further transmission.
“The interesting thing is that because of legal liability you get all sorts of problems in our current culture that makes what was done in Pascagoula in regard to infectious disease so much easier. It slows things down when you don’t get clear, crisp answers,” he said.
Mason said this was why he was able to be in and out of Mississippi in only 11 days.
Moving on
Soon after the oyster epidemic was completed, Mason was called to another investigation of infectious hepatitis at a rural school in Connecticut. After throwing fluorescent dye into a few of the school’s outdoor toilets, the dye appeared in the school drinking fountains. The wells were supplying the water and were being contaminated right from the toilets.
From there, Mason continued investigations, which he said were never boring. His assignment was to look for epidemics, which became the foundation for work done in biological warfare surveillance.
“If a group of alert people trained in epidemiology perform surveillance, they can handle outbreaks such as hepatitis and also deliberate introduction in the form of biological warfare,” Mason said. This was his assignment for the next few years.
He credits the late Alexander D. Langmuir, MD, a Johns Hopkins University professor who founded the Epidemic Intelligence Service branch of the CDC in 1952, with his success and that of others in his EIS class. Langmuir’s famous leadership and charisma attracted some of the most noted doctors in the field today, and his willingness to invest in the young doctors contributed to the good of the country as most of those he mentored went into public health, epidemiology and genetics.
Langmuir is also known for his vision in 1952 in which he linked epidemiology outbreak investigation and future bioterrorism as a government responsibility.
“This was a man who could have been anywhere in the world, but he felt his mission was to prepare the nation to handle infectious disease,” Mason said. “Epidemiology is what it is in the United States today because of that man.”
Today, there are about 50 EIS officers. Their service is no longer a military requirement. Now known as an opportunity with unmatched potential, EIS recruitment is highly competitive.
Oysters and national policy
From 1983 to 1989, Mason was director of the CDC, a historical era for the organization marked by the emergence of the AIDS epidemic. He was then asked by former President George H.W. Bush to serve as the Assistant Secretary for Health. After that assignment, Mason moved back to his home state and served as director of the Utah Department of Health. He also served as a public health minister for five years on a church mission in Johannesburg, South Africa and Accra, Ghana.
Today, Mason is president and CEO of Avalon Health, which operates 35 skilled nursing facilities in Arizona, California, Hawaii, Utah and Washington.
“I’ve retired six times. I’m 76, so it may be time to retire again soon,” Mason joked.
Remarking on his career, Mason said he could have never guessed that the oyster beds of Pascagoula would in part lead him to the helm of the CDC during the most noted epidemic of the 20th century. “But it did,” he said. – by Kirsten H. Ellis
For more information:
- Mason JO, McLean WR. Infectious hepatitis traced to the consumption of raw oysters: An epidemiologic study. Am J Epidemiol. 1962;75;90-111.