by Asim A. Jani, MD, MPH

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Wait a minute; this is crazy. I really should be able to find the building, he thought to himself. Following the directions he had been given, he walked around the area, searching for what he envisioned a governmental public health facility should look like. There were no signs, no building numbers nor any security guards that would make it obvious. Optimistically, he considered this the first puzzle he would have to unravel. Perhaps this was a test in and of itself. Taking the plunge, he walked into the only building in sight, what looked to be a railroad station. Once inside, Dr. Asim Jani realized he had found the Virginia Department of Health (VDH) outpost where he was to spend the next two years of his assignment. This old historic building, full of personality and the disruptive rattling of nearby passing trains, was the temporary main office of the VDH while a new headquarters was being readied.

Dr. Jani had chosen the Commonwealth of Virginia as the location for his engagement with the US Epidemic Intelligence Service. EIS, as everyone referred to it, was the “jewel-in-the-crown,” representing not only the most prestigious applied epidemiology training opportunity in the country but also carrying within its acronym the full gravitas of the Centers for Disease Control and Prevention (CDC), the leading public health agency in the country.

EIS had a natural mystique, being the brainchild of Alexander Langmuir, a brilliant self-possessed and even abrasive visionary who created EIS in the context of the Korean War to deal with biological warfare threats as well as burgeoning domestic public health crises. Several thousand EIS officers have operated as a cadre of public health “special forces” since 1951. They have been at the forefront of solving almost every major epidemic and public health challenge in the US and abroad for more than six decades.

After being trained as an internist, Jani became an infectious disease (ID) specialist, working in Florida and accruing a decade of clinical experience, dealing with a wide variety of illnesses in the hospital and outpatient settings usually originating from a panoply of human pathogens. Solving outbreaks associated with communicable disease etiologies seemed to be a natural transition for him. Applied epidemiology in the broader context focuses on gathering and using information not related to individuals but characteristics of groups of people, their diseases, and potential antecedent risk factors to solve challenges in public health

It was the start of August 2003 at that point, and he was only too eager (and a bit anxious as well) to sink his teeth into a real outbreak. He had done his initial training the month before in Atlanta, at the CDC headquarters, sitting in a chair, listening to lectures. His focus then was on learning the basics, acquiring familiarity with new terms and methods, including a whole taxonomy for outbreaks – concepts such as surveillance, incidence, prevalence, relative risk, and so on. The ultimate purpose of that month, as every EIS officer fantasized, would be to learn just enough “epi” to manifest true serendipity – as Louis Pasteur had uttered, when “chance favors the prepared mind.” Disease detectives, like good doctors and lawyers, need not only book smarts, experience, and attention to detail but also other competencies such as sound judgment, excellent communication, critical thinking, and people skills.

Jani would not have to wait long before that much-anticipated call to action came. A senior public health nurse working in the tuberculosis section of the Virginia Department of Health notified one of his bosses, Dr. Margaret (“Peg”) Tipple of a very concerning situation that was unfolding in a Virginia women’s prison. An annual skin test screening procedure to find inmates who were infected with the tuberculosis germ, known as Mycobacterium tuberculosis (MTB), had resulted in very unusual findings.

Prisons, like other congregate facilities, are notorious for transmission of certain infections, especially tuberculosis – even drug-resistant strains of the bacterium, because of close living quarters, suboptimal ventilation systems, and cohorting of individuals who may be at increased risk of specific communicable diseases. Tuberculosis, a disease of both antiquity and modern times, is primarily caused by relatively prolonged exposure to someone who has tuberculosis disease in the respiratory tract, usually the lungs, resulting in cough and fever, and with the potential for worsening symptoms such bloody sputum, shortness of breath, and profound weight loss.

Upon noticing a spot of expectorated blood under candlelight, the famous poet John Keats said, “…that drop of blood is my death warrant; I must die.” And indeed he, like many before and after him, were victims of the “consumption” – Frederic Chopin, Henry David Thoreau, Andrew Jackson, Franz Kafka, Louis Braille, Eleanor Roosevelt, and Vivien Leigh. Unlike other communicable diseases that tend to have fairly short discrete time periods from the time of initial exposure/infection to the time someone has actual symptoms of disease, clinical TB disease with symptoms may occur from a minimum of a few weeks after exposure/infection to even decades later.

A classic diagnostic test, called Tuberculin Skin Testing (TST), detects the earlier clinical state of being infected before symptoms develop, a phase called “latent TB.” The TST procedure, also referred to as the Mantoux test, after the famous French physician who developed the test, building upon the work of Robert Koch in 1890, involves injecting 0.1 ml of a specific extract of the TB bacterium into the subcutaneous skin. When tuberculin fluid that contains a specific proteinaceous substance called “Purified Protein Derivative” or PPD, made from the tuberculosis germ, is injected in those individuals who had any history of being already infected with tuberculosis, regardless of whether they had symptoms of disease, it is expected the skin will react. This skin reaction is the result of the TB infected patient’s immune system recognizing the PPD material, leading to the accumulation of specific immune cells traveling to the site of the PPD injection, resulting in an actual hard swelling on the skin (known as induration). Fortunately, if someone is identified to have latent TB, certain medications can reduce the close to 10% lifetime risk of developing the actual disease to less than 1%.

The biggest challenges of the TST: 1) determination of a positive TST relies upon physically measuring the amount of induration occurring at the subcutaneous injection of the TST material into the bare forearm; and 2) it is imprecise, in that some patients who are infected with TB may not have a positive TST. Depending on the prior likelihood of having TB, a skin test can be interpreted to be positive based on the range of induration – from 5-15 mm. Importantly TST results must be evaluated at 48-72 hours after TST is injected.

And so it was that when the annual screening at the prison was conducted, almost 500 inmates were “batched” (ie, all of them received the TST injections on the designated Monday), with follow-up TST reading to occur two days later on Wednesday. Instead of seeing the usual 1-2 positive TST results (known as skin test conversion, ie, from a negative flat forearm injection site to a positive area of induration at the location of injection), the staff observed an incredible 48 inmates whose TST results had sufficiently large circumscribed areas of induration to be considered positive.

The prison staff was very alarmed. Was there one or more “superspreaders” (ie, a TB-diseased person whose symptoms resulted in widespread transmission of the infection) in the prison? Often in epidemics a few individuals are responsible for the majority of TB transmission events. Given the complexity of any proposed undertaking to explain why so many individuals were apparently infected with TB in less than a year’s span of time (let alone a formal investigation), the administrator of the prison requested timely assistance from and collaboration with the VDH to help resolve what was clearly a burgeoning crisis. Apart from the genuine health concerns for individual inmates and underlying breaches of disease transmission prevention, the administrator had other legitimate concerns; for example, disruptive behavior on the part of inmates because of fear, distrust, and anger given their vulnerability at being incarcerated. She was concerned about risk to prison personnel and other issues because of the breach. She knew that it was incumbent upon her and her team that concurrent efforts address the possibility of a larger scale TB infection, discover the root cause(s) for transmission and the large number of positive TST results, and put into place both key short and longer-term policy and procedural steps to mitigate further TB transmission.

Dr. Peg Tipple knew all this and more. She brought years of public health experience as a medical epidemiologist working in austere domestic and international settings, solving outbreaks, conducting field investigations, researching novel pathogens, collaborating with ministries of health abroad and politicians and public health officials in urban America. She was soft-spoken and deliberate, imparting a self-assured but tactful scientific demeanor while demonstrating humor, empathy, and practical wisdom in her planning.

Tipple and Jani spoke on the phone with the prison administrator, and it was agreed that at the very least an initial visit to the prison was in order, with the possibility that a formal investigation might be warranted. Neither of them had ever visited a women’s prison before. Located in a remote location of rural Virginia, the prison was spread out over several large brick buildings, with no visible prison bars anywhere to be found. It all looked eerily more like a liberal arts college campus than a prison, where hardened inmates languished, some for almost a decade. Everyone, especially the security guards, was friendly, imparting a sense of quiet, almost relaxed benevolence that seemed at odds with the hackneyed image of stern apathetic and paranoid guards. Jani wondered if this was a function of this being a women’s prison or that this was not a maximum security or federal entity or simply an example of good people trying to do a good job in an overall bad situation: perhaps, all of the above. As he would discover later, the average incarceration period for the 48 (~ 10%) inmates who had tested positive for TB infection based on their TST results was about 2 years. This implied that perhaps these inmates, in contrast to the other 90% who tested negative, may have been more of a transient population, and their TB exposure occurred elsewhere.

The prison administrator was an interesting person. She had been in the leadership position for years, long enough to explain the ink-jet printed sign posted on the inside of her office door. The sign said, “A lot of people get through thinking before they get through thinking things through.” How apropos to this mystery, Jani thought. Little did he know that first day that this would be a talisman for the TST investigation. Within the first 30 minutes of the initial conversation, the team had gathered the basic facts and started planning next steps. A sine qua non of investigating outbreaks is to verify the true excess frequency of the event of concern. In this case, did 48 skin test conversions actually occur this year in contrast to the 1 or 2 per year in previous annual screenings? They were obliged to verify firsthand, as best they could, that appropriate techniques and processes for injecting the tuberculin were followed, plus any other related details they could gather after the fact. This involved examination of the forearms of several inmates who had tested positive, looking for true induration and not other skin reactions such as pain or redness that were essentially irrelevant findings. They conducted interviews, surveyed the prison clinic area, and examined several inmates.

That afternoon as they left the prison discussing next steps in the drive back to the office, the baton was handed over to Asim Jani. Excited to lead his first major EIS investigation, he knew he would need to collaborate with all key individuals, oversee data collection and analysis, and participate in as many endeavors needed to identify just what happened in the prison to cause a sudden 25- 50-fold increase in the number of inmates apparently infected with the tuberculosis bacterium in less than a year. Not only was the obvious health concern present, but also as long as the apparent superspreader(s) remained unknown, he had to mitigate the effects of potential ongoing TB transmission. In this particular setting, there were other factors at play, including dealing with a vulnerable population of incarcerated individuals who had limited mobility, rights, and hope; litigation from the inmates for what could turn out to be breaches at the facility that fostered transmission; and the potential fallout with possible “lock-down” to prevent inadvertent transmission to family, visitors, and staff.

As Dr. Jani settled into his new role, there were several steps that needed to be taken. He had to start learning about prison culture, structure, daily routines, policies, and other aspects that could give him a better idea about the context. He needed to work with the prison physicians on duty to ensure that the 48 TST-positive inmates were assessed for TB symptoms, including fever, cough, and weight loss, making sure that their chest x-rays did not show evidence of TB in the lungs. Once TB infection without actual symptomatic disease was proven, preventive medications could be started for those inmates who desired them. The other more complicated set of tasks involved ascertaining all of the myriad ways in which those 48 individuals interacted with each other and other inmates, where their prison cells were, where they did laundry, where they ate, where they exercised, where they gathered, and where they had come from. He had to figure out if there were any common exposures – common gathering places, common activities, common intra-prison pathways, etc. He painstakingly developed spreadsheet after spreadsheet, keeping meticulous notes and observations during the next several weeks. Every time he thought he had a lead, he learned sooner or later it was a dead end. And like one of his childhood heroes, he emulated Columbo, the famous TV LAPD homicide detective, who kept asking questions, testing different hypotheses, and making repeated observations, often about the same things. And while unlike Columbo, Jani did not smoke, over time he did build up a reputation of sorts, for his Columbo-like haggard appearance as he became ever more frustrated. Over the course of almost two months, the lack of any identifiable common exposure or person to explain how 48 inmates may have all gotten infected with TB resulted in only one important realization. There was no evidence of an occult superspreader as the active contagious source of ongoing TB transmission. But then what could be going on? What alternative explanations, if any, existed as even remote possibilities for this uniquely troubling observation (ie, 48 inmates already at risk for TB given their close quarters living in a prison testing positive for TB infection)?

Three characteristics, central to disease detective work, were particular strengths that Jani called upon: 1) to think outside the box (ie, to look at the same facts others saw and posit relationships and ideas that were non-conventional and imaginative); 2) to not only see existing associations but make new ones between apparently disparate facts; and 3) to create lists of possibilities for causation (ie, construct what is really at the heart of diagnosis in medicine – developing a “differential diagnosis”). A pithy couplet emphasized by one of Jani’s internal medicine teachers was that “the heart of medicine is diagnosis and the heart of diagnosis is forming a differential.” He knew all too well that every primary symptom for which patients sought medical care had multiple explanations and not just a few. The broader the list of explanations, the more likely the correct diagnosis was on that list somewhere; and the faster that comprehensive list could be formulated, even at the bedside in the hospital for ill patients, the more likely the patient would recover, let alone survive. And, so it was that a bit of logic combined with a methodical approach yielded some new ideas for the 48 positive TST results.

A positive TST was ultimately as much a function of the probability of actual exposure and infection to the tuberculosis germ as it was related to the diagnostic test itself. As is the case with any diagnostic test, there are many, often subtle, moving parts. Relevant queries focused on how the tuberculin skin test was rendered from beginning to end. The nature of an inmate’s immune system resulted in a longer list of possible explanations. Perhaps there was a problem with the preparation of the TST syringes, or administration of the actual injections and specific techniques, or how the actual TST reading was rendered, or the quality of the tuberculin fluid itself (possible contamination), or even whether there was some degree of disproportionately intense level of immunologic reactivity, resulting in more induration. There had been examples in the medical literature of positive TST results not due to actual TB infection but rather some completely different cause, such as contamination of the tuberculin fluid. Jani realized that the one particularly important scene in the movie of this unfolding investigation was on the cutting room floor. No one really knew what happened, if anything happened at all, during the actual procedure of the TST preparation. There were no records kept, no log of what TST materials were used; even the names of the staff that prepared the syringes were not known. It was quite justifiable, given the decades of traditional standard practice and tightly scripted annual prisoner TB screening, to assume that the preparation all went according to plan. It was improbable that anything went wrong during this phase. Defeated, but empowered to turn over one last rock, Dr. Jani knew what he had to do, no matter how futile the exercise seemed to him at the moment.

He had met and questioned the core team of prison staff and nurses involved in the TST testing during that initial week when the investigation began. His inquiry even led him to interview several others, including prison guards and personnel who were very helpful as he considered possible exposures to otherwise potentially infected or suspicious inmates. The one group that he had not met was the weekend crew working in the clinic. This group of individuals could, he hoped, shed light on the TST preparation process that occurred the weekend right before the Monday when all 500 inmates were given the TST injections. It was a long shot, but he decided to visit the prison unannounced on the very next Sunday. He had reviewed the TST policy and procedure ad nauseam, it seemed, but he decided it was worth asking this team some questions in person. He met with a few of the nurses and clinic staff, engaging them in a relaxed informal way. He went to the same refrigerator as he had several times in the weeks before during the earliest stage of the investigation. But this time the staffing was sparse and the closed clinic atmosphere heavy with boredom. He did not think of these conditions as conducive for anything except a colossal waste of time. Driving there that bright Sunday morning, he thought to himself, a secular scientist that he was, that if there was a deity associated with EIS, he had done enough penance. He now deserved a boon, a piece of good luck or even a small catalyst to get him past the quagmire of what appeared every day to be an investigation that had gone cold. He begrudgingly opened the refrigerator door, kneeled down one more time and started inspecting all too familiar shelves. This time something was eerily different. The old white tray labelled “TST material” had been moved from its usual place. And almost like a voice-over while he was searching for anything unusual, he was simultaneously engaged in a conversation with one of the weekend nurses about that particular Sunday when she and her colleagues had drawn up the TST syringes. She exclaimed, “I think I know what happened.” She continued, “I never thought we had so many people infected with TB, but rather that a bunch of inmates got that contaminated TST fluid.” Speaking with a pejorative tone about a nurse colleague who was not present at the moment, she amplified, “I told her not to use that vial of TST fluid because it was cloudy and not clear like all the other TST fluid vials.” As this narrative went on, Jani just happened to pull out the tray of TST materials and much to his chagrin, found a misplaced bottle of Tetanus-Toxoid fluid, used for vaccinating inmates against tetanus. Traditionally a childhood disease but now decreasing in frequency (with about 30-50 cases per year), tetanus occurs mainly in adults and with almost 75% of deaths among those > 60 years of age. The fluid in the tetanus vaccine bottle was coincidentally cloudy! Experiencing the intuitive joy associated with solving a challenging calculus problem, Jani quietly thought, this was not a coincidence. He felt both elation and despair at the same moment. Could a vial of Tetanus-Toxoid fluid have been inadvertently used to draw up several TST syringes? Who would do that? And how could such an error happen? As he grabbed both the Tetanus vial and a TST vial, he felt a surge of butterflies on behalf of those poor inmates as well as the staff member(s) who may have made the error. Both bottles were made by the same manufacturer, both were the same size, and both had green tops, only differing slightly in shade and hue. Anyone could have made the mistake, he thought out of compassion and empathy. Regardless of how and why, the question of culpability landed like a lead brick – how was anyone going to declare this mistake, either directly or on behalf of another colleague? And, if no one did, how was he of all people going to prove, what had to be considered at this stage, a hypothesis as outlandish as this? Had this ever happened elsewhere? What was known about injecting Tetanus-Toxoid fluid subcutaneously rather than its usual recommended route, into the muscle? And even if his own team believed this as a plausible explanation, what would the prison administrator think or say? What kind of impact would it have on her job? Most importantly, if this were ever proven or even worse, not proven but insinuated as the best and last possible explanation, how would the inmates take the news?

As he drove back home that Sunday, Jani was already considering next steps. Something had to be done in the coming weeks. Even if the Tetanus-Toxoid fluid substitution explanation would be proven incorrect, the central issue was that there really was no other viable competing hypothesis. Discussions not only with Dr. Tipple but also other colleagues including those at CDC confirmed that on a practical level there were three major approaches worth exploring – retesting and observing inmates with repeat but 100% correct TST procedures (clinical assessment), soliciting key information about the initial and subsequent TST experience (epidemiological assessment), and performing key laboratory tests. Clinically, it would be of potential benefit to retest as many of the 48 inmates with presumably falsely positive TST results. Indeed, assuming these 48 inmates had no real prior TB infection, they would be expected to have no skin test reaction after they got retested with non-contaminated tuberculin fluid as originally intended. Epidemiologically, it would be supportive of the inadvertent substitution explanation if it could be shown that the overall experience surrounding the original “wrong” fluid (Tetanus-Toxoid fluid) was very different and unusual compared to the experience involving being reinjected with the PPD fluid. And finally, from a laboratory perspective, it would be very helpful if there was 1) some other test in addition to the TST procedure that confirmed a lack of verifiable tuberculosis infection and 2) a way to show that somehow the Tetanus-Toxoid fluid these 48 inmates received subcutaneously resulted in an exaggerated level of immunity to tetanus since prisoners routinely already received tetanus vaccine intramuscularly every few years as per prevention guidelines. The real challenge would involve finding out if any or all of these three approaches could be used (ie, if there was sufficient validity to the clinical, epidemiological and/or laboratory methods that some practical evidence could be gathered that justified the definitive nature of breach in TST administration).

Once there was a credible and feasible plan outlined, and buy-in was established through discussions with prison administration, the team began with a systematic approach to this second phase of the TST investigation. The very first step involved ensuring that utmost respect was offered to the vulnerable prisoners who would have the central role moving forward. The VDH team had to uphold the highest ethical standards for directly interacting with the prisoners (surveys, interviews, TST retesting, laboratory testing), and give proper deference to the institutional ethical review boards and processes at the CDC and other groups as needed. Prison inmates are admittedly a vulnerable population, with limited rights, mobility, income, and access to care. Ever since the Nuremberg trials after WWII, the global community had a paradigm shift in how scientific research, experimentation, and engagement with potential human subjects and groups, especially those considered vulnerable such as prisoners, children, and the mentally ill is conducted. Lack of control of events in their daily lives and subsequent dependence on the institutions where they are incarcerated particularly characterizes the vulnerability of prisoners. The team adhered to a standard process of obtaining informed consent for all procedures responsive to privacy concerns. Proactive, timely education was provided to prisoners about their condition, including complications and patient safety issues.

The VDH team proceeded to systematically retest as many of the available original 48 inmates with a positive TST who were willing to undergo another TST procedure. All of the remaining 35 (of 48) inmates who agreed to be retested were found to be negative when the VDH team retested them under strict quality assurance conditions. The VDH team also proceeded to do focused interviews and surveys of each of these 35 retested inmates to solicit their observations about the comparative experience around original and subsequent TSTs.

Surprisingly, formal analysis of the pre- and post- procedure data for the original and 2^nd TST procedures resulted in a clear difference for the two testing sessions. Originally, the inmates recalled multiple symptoms at the site of the first-time TST injection (pain, itching, redness, pain, and anxiety) that in turn not only occurred from a minimum of 15 minutes to 48 hours after injection but also lasting up to 90 days.

There was a significantly higher proportion of inmates recalling the color of the initial TST fluid in the syringe to be cloudy (and not clear as it should be). Laboratory testing also showed there was almost a 3-fold higher percent of originally tested inmates of the 48 inmates who had levels of “antibody” to tetanus (a marker of immunity) considered hyper-immune compared to another group of inmates who had received the usual Tetanus-Toxoid vaccine in their muscles. This clearly indicated that the original 48 inmates had gotten exposed to a greater intensity of Tetanus-Toxoid vaccine, unrelated to the usual schedule of receiving that vaccine. Finally when a special new blood test that was about to be officially released for general use in the population was offered to the remaining inmates among the original 48, the results independently showed that none of those inmates had any immune reaction to tuberculosis, likely because they had no evidence of tuberculosis infection. This further supported the findings that 35 of 35 inmates were TST negative upon retesting. All of these combined results indicated that inadvertent substitution of Tetanus-Toxoid vaccine fluid for the normal TST fluid resulted in 48 inmates getting false-positive TST results. And even some simple arithmetic supported this; a single 5 cc syringe that would have been used to fully draw up the maximum amount of TST fluid (in this case Tetanus-Toxoid vaccine fluid instead) was just sufficient to provide 48 doses of 0.1 ml each for the tested inmates.

The investigation results and the related implications for what ultimately had happened to the 48 inmates were duly conveyed in a formal report prepared for the prison administration. The administration would then have the responsibility of informing and updating the prisoners. They would have to share the results in an open and cogent manner and demonstrate the appropriate contrition and commitment to preventing any inadvertent substitution of the wrong TST fluid in future TST procedures. Policies were changed including more specific, consistent labelling and handling of TST fluid products, training and education for staff on standard protocol and patient safety measures to prevent errors and clear safeguards in all TST administration procedures. Jani went one step further as he was required to – notifying the Food and Drug Administration (FDA) about the incident, and inquiring about any other examples of inadvertent substitution of TST fluid. His colleagues at both the CDC and the FDA were taken aback at the findings of the investigation. In an ironic twist that was both sad and surprising, he discovered that almost 22 years prior, a young EIS officer had published a report on the inadvertent administration of a similar tetanus-containing vaccine for TST fluid. Among the potential causes for this error was listed the shocking similarity in packaging for the TST and tetanus-containing vaccine – bottle size, shape, labeling as well as the bottle cap (Figure 1). This preventable situation had apparently not significantly changed for more than two decades.

The CDC and FDA would ultimately release an important public health notification in the premier weekly journal, the Morbidity and Mortality Weekly Report (MMWR) in its July 2004 issue. The MMWR has a grand history, having begun in 1878 when the US Congress passed the National Quarantine Act. Over the subsequent 74 years, this important publication would evolve until it acquired the MMWR title. From 1952 until the present time, the MMWR would represent the most informative and timely method by which some of the most significant public health findings would be communicated to the world, including the first report of infections associated with the then unknown virus, HIV, to the events of September 11, 2001, and later the anthrax attacks along with a wide range of many other updates for a myriad of diseases and risk factors. The July 2004 MMWR issue described that as of April 2004, “five reports of medication error involving tetanus toxoid (TT) from a health-care provider were identified…. As of March 2004, approximately 100 patients had been identified in reports of Tetanus-Toxoid vaccine containing administration instead of PPD. A total of 21 states have reported both clusters and single cases.”

Dr. Jani’s investigation of the 48 female prison inmates with supposed tuberculosis infection was a classic “outbreak of a pseudo-infection” – an alarming excess frequency of something that ultimately was not an actual infection but triggering a cascade of events that presumably were related to prevention and control of an infection. But sleuthing, serendipity, and steadfastness resulted in all but confirming firsthand the culpability of a medication error that was at the heart of the enigmatic investigation. Many lessons were learned, not the least of which was aptly captured in a quote from Arthur Conan Doyle, in the Casebook of Sherlock Holmes – “When you have eliminated all which is impossible, then whatever remains, however improbable, must be the truth.”

Discussion Questions

 

1. The case reports on screening prisoners for tuberculosis using a tuberculin skin test (TST). Screening for TB is not recommended as a general measure for individuals in U.S. communities.
2. Is this an advisable practice for individuals admitted to jails or prisons? Why?
3. What further tests should be done on TST positive individuals to determine if they have active TB?
4. For TST positive incarcerated individuals who are found not to have active tuberculosis, is prophylactic treatment recommended? Why?
5. A tuberculosis (TB) blood test, also called an Interferon Gamma Release Assay or IGRA is now available.   How would use of this test have been helpful in this situation?
6. As this case describes, this is not the first time the error of using an incorrect biological for the TST screening has occurred. How would you avoid this error in the future?

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ABOUT THE AUTHOR

At the time of the case, Asim A. Jani was an EIS officer (Epidemic Intelligence Service) for the Centers for Disease Control and Prevention. Currently, he is Hospital Epidemiologist at Orlando Health, one of Florida’s most comprehensive private, not-for-profit healthcare networks, based in Orlando, Florida.

See also:

• “The World’s Deadliest Poison,” by John Marr and Marcus Horowitz
• “Mystery in the Pines,” published in the Journal of Public Health Management and Practice
• Introducing Backstories in Epidemiology: True Medical Mysteries
• Introducing a New Series of Epidemiologic Case Studies: Podcast with Dr. John Marr

Read more Backstories in Epidemiology: True Medical Mysteries, coming soon:

• “Bad Blood: The Gift of Giving,” a malaria outbreak in New York City
• “Appendectomy Masquerade,” an epidemic initially attributed to appendicitis in upstate New York
• “The Babies Are Dying,” newborn deaths in a West Virginia rural hospital nursery
• “Clam Aches,” an outbreak at a church picnic from Maine clams
• “Of Bites and Men: The Most Dangerous Urban Animal,” a story where the number of human bites exceeds shark bites