SYMPOSIUM
set. When the results were analyzed, no common food items were reported eaten by all three case-patients during their potential incubation period for typhoid fever.
ANOTHER CASE
The TDH epidemiologist was not de- terred: “What we need now is another case.” She believed the common food item consumed was raw oysters, even though the two male case-patients couldn’t recall if or when they may have eaten them during the incuba- tion period. At this point, there was nothing to do except wait and see if other cases would be reported. As (bad) luck would have it, about
a week later, another PFGE-matching case of S. Typhi was reported. This newest case-patient, also an adult male, lived in the San Antonio area. When interviewed using the long questionnaire, he reported having traveled to Galveston several weeks before his illness and eating raw oys- ters there once. But, again, all four outbreak case-patients reported no common food item. Once again, the TDH epidemiologist said, “What we need now is another case.” She had a strong suspicion that raw oysters were the culprit food item, but there simply weren’t enough cases reporting them to proceed with investigations of that potential source.
The pace of the outbreak picked up.
Two additional cases with the same PFGE patterns as the first four cases were reported two days later. Both adult male case-patients lived in Aus- tin and had not traveled outside Tra- vis County during the several months before their illness. The six outbreak case-patients had developed illness during a three-week period between mid-July and early August; four were hospitalized for their illnesses. There was clearly a food item in
commercial distribution that was contaminated with S. Typhi, but its identification was eluding investiga- tors. With a small number of cases, and considering the long potential
40 TEXAS MEDICINE February 2017
incubation period and the difficulty most people have remembering what they have eaten even within the past few days, this lack of conclusive proof was not surprising. It was, however, frustrating. The public health investi- gators were anxious to get the causal food item out of circulation and pre- vent more serious illnesses. The Austin/Travis County Health
and Human Services Department (ATCHHSD) epidemiologist attempt- ed to interview the two new case- patients. She interviewed one, using the 14-page questionnaire modified to include several Austin-area eat- ing establishments. The case-patient reported consuming raw oysters at a restaurant in Austin before his illness onset, though he couldn’t remember the date. The epidemiologist was not able to contact the other case-patient. She called him multiple times and even went to his home, leaving a busi- ness card and a questionnaire for him to complete. He did not respond. Fi- nally, after several weeks, the case-pa- tient called and was interviewed. He had been hospitalized for his serious illness, and without health insurance he was working long hours to pay for his large medical bills and to make up for lost pay. He did not report eating any raw oysters. Still, no common food item was being reported by all six out- break cases. The interim health authority for
ATCHHSD was concerned and frus- trated when he learned the two Austin cases were part of the outbreak and it had not yet been solved. He suggested that he, the ATCHHSD, TDH epide- miologists, and the two Austin case- patients meet and see if the two men might recall something that could lead to the identification of a common food establishment and common food item. Because the case-patients agreed to discuss their illnesses with each other, confidentiality laws would not be violated. During a dinner meeting, conversation about the two men’s ill- nesses flowed easily. In fact, they de- termined they had both eaten at the
same restaurant before their illness onsets. And the restaurant served raw oysters. The case-patient who had previ-
ously reported he likely ate raw oys- ters now recalled this had occurred on either a Monday or Tuesday evening in mid-July and possibly again a week later. When he heard the name of the restaurant, the second case-patient remembered he had also eaten at that establishment at about the same time. He said it would have been on a Monday evening, as he went to watch preseason Monday night football. He also recalled that although he didn’t usually eat raw oysters, he did once because he wanted to catch the at- tention of a cute-looking waitress. As the two men compared dates on their calendars, they realized they both ate at the restaurant on the same Monday in July. Meanwhile, the first two case-pa- tients identified in the outbreak had contacted their local health depart- ments and reported they remembered eating raw oysters more than once. The two men did not eat the oysters at any of the same restaurants. When the TDH epidemiologist
first suspected raw oysters were the typhoid fever vehicle in the outbreak, she contacted the head of the depart- ment’s Seafood Safety section, which is responsible for inspecting and in- vestigating the harvesting, packing, and shipping establishments that pro- vide raw oysters to restaurants and stores. These are vital functions, as raw oyster consumption is associated with severe and often fatal infections, particularly among immunocom- promised people. The usual culprit bacterium is Vibrio vulnificus, which normally inhabits the warm coastal waters of the Gulf of Mexico. Immu- nocompromised people who consume raw oysters or who have a break in their skin while wading in the Gulf can develop V. vulnificus septicemia within a few days. These infections are often fatal. In Texas, about a dozen cases each year are reported that are
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68