In Part I of this article, an introduction was made to the Rapid Response Teams (RRTs), describing their creation, expansion and operation. In this part, we will cover real-world examples of RRTs responding to incidents.
The advantages of RRTs are not limited to best practices or face-to-face meetings, but extend to the actual work done in the field on foodborne illness outbreaks and other food and feed emergencies. Every RRT has an outbreak investigation story to tell, and while only a few can be illustrated here, these stories demonstrate the persistence and commitment of RRTs to go to the end of the road.
One Bad Apple: The Response to the Caramel Apple Outbreak
The old adage “One bad apple spoils the barrel” reminds us that one weak link can derail an entire process. In the response to an outbreak of listeriosis linked to caramel apples last winter, the RRTs involved in the investigation showed no weakness in their response efforts. The listeriosis outbreak involved 12 states, 6 of which have established RRTs. The pathogen, Listeria monocytogenes, infected 35 people, 34 of whom were hospitalized, with 3 reported deaths. The dates of illness ranged from October 17, 2014, to January 5, 2015.
The Importance of Asking the Right Question: Listeria in Caramel Apples?
For weeks, state epidemiologists interviewed ill patients about their food history and exposures with no success in identifying a common food source. When interviewing ill patients, epidemiologists use a standardized questionnaire that asks about exposure to specific food products, as well as environmental factors and behaviors that are typically associated with the pathogen of interest.
For cases with listeriosis, questions typically focus on consumption of unpasteurized dairy products and ready-to-eat deli meats. Caramel apples, which had never been known to carry Listeria, were not on the list. When epidemiologists cannot find a common food source among patients, they sometimes move to open-ended interviews. Such interviews led the Texas Department of State Health Services (DSHS) to identify caramel apples as a common food source among their cases on December 15, 2014.
The findings from Texas were shared by the U.S. Centers for Disease Control and Prevention (CDC) on a national call for all states with listeriosis cases. This prompted the Minnesota Department of Health (MDH) to reinterview cases for exposure to caramel apples, and MDH discovered three out of four cases reported eating caramel apples before illness onset.
At this point, things moved rapidly. On December 16, CDC created a new supplemental questionnaire with a specific focus on caramel apple consumption and asked states to reinterview patients. The results of these new interviews allowed CDC to link caramel apples as the suspected vehicle in the multi-state outbreak.
With a specific food implicated, states could begin to conduct a trace-back investigation, gathering information that would point to where ill patients had purchased caramel apples, and in turn, what companies had sourced the product to stores.
Hot on the Trail: Tracking Down the Source
The RRTs visited numerous companies and collected shipping and receiving records of caramel apple manufacturers and distributors.
First on the scene, the Minnesota RRT contacted seven caramel apple manufacturing and distribution companies that were linked to Minnesotan illnesses. Three days after caramel apples were identified as a suspect vehicle, the Minnesota RRT identified the name brands of caramel apples and their retail locations, as well as the growers used by the brand manufacturers, which they shared with the U.S. Food and Drug Administration (FDA) and other states involved in the investigation. MDH released the caramel apple brand names and retail locations to the public in a press release on December 18.
One of the apple growers identified by the Minnesota RRT was Bidart Brothers, located in California. California had also been busy investigating the caramel apple purchases of their ill cases, which led to implicating a California caramel apple manufacturer, Happy Apples (which had a second manufacturing location in Missouri). The next day, the FDA San Francisco District Office and the California Department of Public Health activated the California Food Emergency Response Team (CalFERT) and began to obtain records from Bidart Brothers and Happy Apples.
The Missouri RRT, which includes the Missouri Department of Health and Senior Services, the Missouri Department of Agriculture (MDA) and the FDA Kansas City District Office, also activated on December 19, investigated the two caramel apple manufacturers located in-state whose brands were associated with ill patients. Their investigation included records collection and sampling, and unveiled only one common apple supplier: Bidart Brothers.
Of note, both the CalFERT and Missouri RRT activations involved a virtual Unified Command, which is an authority structure in which the role of incident commander is shared by two or more individuals, each already having authority in a different responding agency. Typically, Unified Command is housed in one location, but the spread of team members across the state did not allow for everyone to be under one roof. The use of technology, such as FoodSHIELD, to share information and documents in real time allowed this system to function successfully.
Using the records and information collected by these RRTs, FDA was able to trace back the apples consumed by 11 case patients through four manufacturing legs, leading to a convergence at Bidart Brothers. Three days before Christmas, and just 1 week after identification of caramel apples as a common food vehicle among ill patients, Bidart Brothers issued a recall of Granny Smith apples sold in 2014 to three customers known to use them to produce caramel apples (Happy Apples, California Snack Foods and Merb’s Candies). These companies all issued their own recall before the end of 2014, and the recall expanded on Christmas Eve to all Bidart customers who had received and used Granny Smith apples for caramel apple production.
Caramel, Toppings and Sticks, Oh My: The Search for the Real Culprit
With a complex, multi-ingredient product such as caramel apples, the contamination could have come from any of the numerous components involved. Determining how and why the Listeria was present in the finished caramel apple product was the new focus of RRTs as they began to identify and investigate manufacturers that had supplied product that caused illnesses.
From the start, it was clear that numerous unrelated caramel apple brands and manufacturers were associated with the outbreak. This in itself suggested that the contamination was not from a specific caramel apple processing facility, but rather was the result of a contaminated caramel apple ingredient or component used by multiple manufacturers. The variety of caramel apples that ill patients consumed further supported the hypothesis that it was not a common topping that was the source of the Listeria.
The Missouri RRT kicked off intensive sampling efforts at its two caramel apple manufacturers. Demonstrating interagency resource sharing and synergy, the Missouri RRT used both the state’s public health laboratory and an FDA laboratory to test the food samples.
Due to the timing of the investigation and sample collection, the Missouri laboratory worked through Christmas Eve and Christmas morning to complete the sampling analysis. The results of the on-site investigation and sample testing suggested that neither the caramel apple processing facility nor the nonapple components of the caramel apples were the source of the Listeria, which supported the hypothesis that the apples alone were the contamination vector.
Meanwhile, CalFERT initiated on-site investigations at Happy Apples and Bidart Brothers on December 23, which included environmental swabbing, as well as sampling of caramel apple ingredients, wooden sticks and plastic clamshell packaging. Two days into the new year, seven of the environmental swabs collected by CalFERT at Bidart Brothers were reported positive for L. monocytogenes and were later confirmed as a pulsed-field gel electrophoresis match to the outbreak strain. One environmental swab collected at Happy Apples was also a match to the outbreak strain.
Based on the positive environmental samples found in the packing facility, on January 6, 2015, Bidart Brothers expanded its recall to all Granny Smith and Gala apples produced in 2014.
At this point, Minnesota RRT had collected and tested 30 samples from three different lots of Bidart Brothers apples currently on hold at a Minnesota caramel apple manufacturer, eight of which were positive for Listeria and were later shown to match the outbreak strain. This confirmed that contaminated Bidart Brothers apples were distributed to Minnesota firms, and MDA issued a consumer advisory on January 9, listing 16 brands of caramel apples produced in Minnesota using recalled Bidart Brothers apples (Figure 1).
Case Closed: RFRs, Effectiveness Check and After Actions
After an incident such as this one that involved multiple, rolling recalls, regulatory investigators will work to contact all companies in the supply chain to ensure all contaminated product is removed and unavailable for sale or consumption. Bidart Brothers apples and caramel apples processed using these apples were distributed in many states, so these activities were not unique to the RRTs featured in this article.
Of note, the Minnesota RRT worked over the Christmas holiday to contact companies affected by the recall. It also requested that companies with positive samples submit a report to FDA’s Reportable Food Registry (RFR).
The national outbreak investigation closed in mid-February. Upon closure of their individual investigations, the activated RRTs held an After Action Review meeting (hot wash) to discuss lessons learned from the activation.
Minnesota, Missouri and California presented their investigational findings at the Manufactured Foods Regulatory Program Alliance meeting in March 2015. There was strong consensus that this particular outbreak response exhibited effective coordination among the states, local authorities and FDA, resulting in rapid identification of the product. The RRTs’ environmental health, epidemiology and laboratory programs were almost seamless in communicating findings from trace-back, sampling and environmental investigations, allowing other agencies at the state and federal levels to quickly act upon those results to identify contaminated product and remove it from commerce.
Protozoa Rising: The Tale of the Iowa and Texas RRT Response to a Multi-State Cyclospora Outbreak
In the summer of 2013, 631 people in 25 states were infected with Cyclospora. Eight percent of ill patients were hospitalized and there were no reported deaths. The dates of illness ranged from June 1 to August 29, 2013.
Cyclospora cayetanensis is a rare parasite that is spread by consumption of food or water contaminated with feces, which can cause watery diarrhea for an average of 57 days if left untreated. Cyclospora, which is endemic in developing countries, has a low infectious dose, and the time between becoming infected and becoming sick is usually about 1 week. Ninety to 99 percent of cases in the U.S. are foodborne, and previous outbreaks of Cyclospora have been associated with fresh produce.
During the investigations, two separate but concurrent outbreaks associated with bagged salad mix and fresh cilantro were identified in at least three states.
Houston, We Have a Problem
For both Iowa and Texas, the sheer number of cases above the typical baseline level of Cyclospora infections clearly indicated that a rapid, coordinated response was needed. To put this in perspective, in a 6-day period (June 27 to July 2), the Iowa State Hygienic Laboratory (ISHL) reported six confirmed cases of Cyclospora, but previously there were only 10 cases of Cyclospora reported in Iowa in 15 years, since cyclosporiasis became a reportable disease in 1996. By the outbreak’s end, 140 cases were reported in Iowa. Texas, on the other hand, typically saw fewer than 10 cases of cyclosporiasis per year, almost exclusively cases where the patient had traveled to a country where Cyclospora is endemic in the 2 weeks prior to the onset of illness. The summer of 2013, however, presented an unusual number of cases of domestically acquired cyclosporiasis in what appeared to be a repeat of a similar spike seen in the summer of 2012, but on a much larger scale. The final case count in 2013 was 270.
Based on their experience with the smaller outbreak in 2012, in which a causative food vehicle was not identified, investigators in Texas knew they had to act quickly and leverage all available resources to get to the bottom of what was shaping up to be an annual phenomenon.
Steven Mandernach, chief of the Food and Consumer Safety Bureau of the Iowa Department of Inspections and Appeals (DIA), sums up the underlying mission of all RRTs: “Our goal, when investigating a foodborne illness, is to as quickly as possible identify the source of the outbreak and stop the spread.”
In Iowa, the detection of these cyclosporiasis cases triggered a joint statewide investigation involving DIA, Iowa Department of Public Health (IDPH), ISHL, local health departments, the FDA Kansas City District Office and Nebraska officials who were also investigating related cases of cyclosporiasis.
“The Rapid Response Team assisted in this effort by promoting coordination and communication among the various agencies, and making available dedicated staff [who] were focused on the early detection of potential foodborne illness,” continues Mandernach. “Excellent communication and collaboration between the involved local, state and federal agencies, and the cooperation of the public, medical providers and the food industry were key to our ability to definitively identify and control the source of the outbreak in Iowa.”
The Importance of Epidemiologic Data
Detecting a Cyclospora outbreak can be especially difficult, as testing must be specifically requested by a physician and diagnosis requires a visual analysis of a stool sample conducted by a skilled technician using a microscope to look for parasites and their eggs or cysts. Once a Cyclospora outbreak is suspected, it is crucial to quickly reach out to medical providers to encourage them to request testing for patients with symptoms consistent with cyclosporiasis.
To this end, the Texas DSHS issued a public health advisory within days of realizing that there were cases in-state associated with a national Cyclospora outbreak. The IDPH similarly found that prompt and proactive outreach to the medical providers was essential in identifying the scope of the outbreak, and implemented extensive use of social media to connect with providers.
Current laboratory tests cannot distinguish between different strains of the parasite C. cayetanensis, unlike characterization tools that are available for more common foodborne pathogens. Thus, disease surveillance and outbreak detection tools like PulseNet are unable to help characterize these outbreaks. Many institutions are working on developing new molecular tools that could distinguish one strain from another.
As a result of the Cyclospora outbreak, as well as a smaller cryptosporidium outbreak that same year, the Iowa Department of Inspections and Appeals is collaborating with the State Hygienic Laboratory to conduct surveillance and improve testing methodologies for parasites in fresh produce. The laboratory has consulted with national and international experts in developing this project.
For these reasons, epidemiologic investigations are extremely important during Cyclospora outbreak investigations. Investigators must rely on food histories of patients and statistically significant food exposures to determine which cases are linked to each other and to particular food items/sources.
Few understand the importance of this point better than Texas investigators, who were stuck in the middle of two concurrent, independent Cyclospora outbreaks (Figure 2) and diligently chased down bagged salad mix based on findings from the Iowa outbreak until epidemiologic data from Texas cases and restaurant clusters began to demonstrate association with consumption of fresh cilantro, rather than salad mix.
Making the situation even more confusing, the earliest restaurant clusters involved cases that overlapped the Iowa outbreak epidemiological curve.[1] Those appeared to be associated with consumption of leafy greens, as ill patients in these clusters were reporting menu items that consisted of leafy greens (of different varieties) and were not reporting cilantro consumption or consumption of items that included cilantro.
With limited ability to further characterize Cyclospora infections and poor prospects for finding and successfully testing potentially contaminated product, it becomes imperative to collect as much epidemiologic data as possible and to be open to changing the direction of the investigation based on the analysis of that data, as that is the only way to determine if cases are truly linked.
In this case, strong evidence from epidemiologic investigations ultimately led to the recognition that the outbreaks were separate and unrelated.
Overcoming Trace-Back Challenges
For both RRTs, once the epidemiology partners had identified restaurant clusters and common items consumed at those restaurants, the regulatory partners traced those potential vehicles through the food distribution and production system.
“Food histories are challenging; most of us do not always remember the foods we eat during the past several days, and especially the past several weeks,” Mandernach says.
Compounding the investigation was the fact that by the time illnesses were identified, most if not all of the suspect product was no longer on the shelves.
“Because it can take more than a week for the first symptoms to appear after ingesting the contaminated food, there wasn’t a product on the shelf to be examined for the parasite,” Mandernach says. “As a result, most of the foodborne illness investigation focused on trying to trace back suspected food products through the food chain to identify a common source that could explain all of these illnesses.”
The Texas RRT’s trace-back effort was especially challenging, as they were faced with more than 70 point-of-service clusters, and at the beginning, nobody knew they were chasing two separate outbreaks. Of the 70 clusters of illness, 26 had more than three people associated with the point of service, and even fewer had adequate epidemiological and trace-back information to conduct an effective investigation.
Texas’s regional and local health departments played crucial roles in investigating the illness clusters and collecting records at the initial point-of-service locations, information that was then handed over to state and federal investigators to trace back further in the distribution chain at the supplier, distributor and grower levels.
In the early stages of the investigation, when the Texas RRT was primarily focusing on leafy greens, investigators were looking at the distribution records associated with several types of leafy greens served at the implicated restaurants, including different types of lettuce and ingredients commonly found in salad mixes.
At one point, the Texas RRT was investigating and tracing the distribution pattern of 16 food items, looking for a common distributor or supplier that would explain how all these unrelated restaurants had ill customers. Eventually, a case-control study was performed at one of the restaurant clusters and determined that out of 58 ingredients used in preparing items on the restaurant’s menu, only 10 were significantly associated with cyclosporiasis. The only ingredient eaten by all 25 case patients was cilantro, the ingredient most strongly associated with the illness. These findings were a pivotal moment in the Texas investigation, where the focus shifted from leafy greens in salads to fresh cilantro.
A trace-back challenge that resonates with the experiences of the Iowa and Texas RRTs is that the quality, comprehensiveness and level of detail in distribution records vary widely based on the company. The more links there are in the supply chain, the greater the risk of one or more of those companies having incomplete, inaccurate or missing records that are needed to demonstrate where the product came from, what happened to it in the company and where it went afterward.
In contrast, the Iowa restaurant clusters were primarily associated with two restaurant chains that shared a parent company, which greatly simplified the number of possible distribution channels to investigate, and streamlined the process for obtaining the information, since the corporate parent had access to distribution information for all of its restaurants.
Using on-site facility visits and phone conversations with the restaurant chains’ corporate parent regarding the source of various food items that ill people reported eating, the Iowa RRT was able to demonstrate that the prepackaged salad mix consumed by approximately 80 percent of ill patients was obtained from a common source, and was also able to pinpoint the source of the salad mix down to the farm level. At that point, regulatory officials quickly confirmed that the implicated salad mix was no longer a threat to the public and issued a press release stating, “Iowans should continue eating salads, as the implicated prepackaged mix is no longer in the state’s food supply chain.”
Using Lessons Learned to Improve Future Responses
The Importance of Outreach and Communication with Industry
During a major outbreak such as this one, the impacted industries are a critical component of the investigation. Very early on during the outbreak, the Iowa RRT reached out to the corporate structure of the national restaurant chain associated with the outbreak and explained that the epidemiologic data showed a cluster of patients with cyclosporiasis who had all eaten at the same restaurant chain in the 2 weeks prior to having symptoms of illness.
As the investigation progressed, the Iowa RRT continued to frequently communicate with impacted restaurant locations, sharing findings about common food exposures among ill patrons. In return, they received quick turnaround on information requested and insight into the distribution of the suspect food vehicles, all of which fueled the trace-back investigation. The Iowa RRT’s experiences during this outbreak reinforced and cemented a commitment to opening corporate lines of communication early in investigations.
Handling Media Requests
All agencies in the Iowa RRT experienced a surge in media requests during this outbreak that posed a challenge, requiring vast amounts of time and resources. Moreover, the media requests commonly required the expertise of multiple officials handling different parts of the investigation. This required even more time to coordinate talking points and procure additional information from subject matter experts.
In the future, the Iowa RRT plans to move to a media availability format rather than individual interviews. This way, the media can access all the experts at one time.
Strengthening Integration at the Local Level
In August, CDC sent two Epi-Aid teams to Texas to help interview and investigate the cases of cyclosporiasis. In Texas, a home-rule state, many local health departments were strapped for adequate resources to rapidly interview all 270 case patients and investigate the restaurant clusters. Coincidentally, the DSHS had recently obtained approval to fund an epidemiologist position at 16 local health departments, which was not in place in time for the 2013 Cyclospora outbreak.
Texas used the experiences from this 2013 outbreak to further demonstrate the need for these positions and inform how these positions should function and collaborate with the DSHS during investigations. These additional personnel and processes were in place in time for the 2014 Cyclospora outbreak and had a hugely positive effect on the epidemiologic investigation and collection of initial records at the retail level to inform the trace-back effort.
More Fat to Chew: Michigan RRT Responds to Contaminated Grease in Feed
On August 11, 2014, the Michigan Department of Agriculture and Rural Development (MDARD) was notified by a farm in Howard City, MI, that its turkeys were experiencing a higher-than-normal mortality rate. The Michigan RRT activated on September 26 in response to mounting evidence of positive feed and grease samples containing high levels of lasalocid, an ionophore drug approved for use in poultry and other species of livestock at approved levels. The Michigan RRT and FDA contacted the farm to assist in determining the cause of the lasalocid toxicity. Lasalocid levels from feed samples taken on the farm were found to be four to six times the prescribed feeding rate for turkeys.
The Michigan RRT worked with MDARD’s Geagley Laboratory and the Michigan State University Diagnostic Center for Population and Animal Health (MSU-DCPAH) to analyze samples of dozens of feed ingredients used on the farm to determine the source. The team discovered lasalocid present in the grease the farm used in both its turkey and swine feed formulations. Lasalocid is not approved for swine and has been fatal to horses and dogs if ingested. Grease is typically added to feed as a flavoring agent and to increase fat content.
The Michigan RRT faced a unique situation in the lasalocid feed contamination. The implicated ingredient had no approved laboratory methodology to quantify lasalocid, so initially no samples were run. FDA reported it would take 6 to 8 weeks to develop a method; however, MSU-DCPAH was able to conduct a qualified analysis for the presence of lasalocid. Within a few days, samples of grease/oil suppliers were analyzed. Only one carrier sample tested positive for the lasalocid.
The Michigan RRT and FDA investigated the sources of the adulterated grease and determined that a restaurant recycling firm in Michigan received an out-of-state industrial processing waste oil product called “Lascadoil” that was brokered as soy oil. The Lascadoil was intended for nonfood or biofuel uses, but inadvertently crossed over to the feed ingredient stream. Feed manufacturers and farms in Michigan and several other states were directly impacted by this diversion.
A nationwide recall of the adulterated grease was issued on October 23. Feed trace-backs are less common, but this response reaffirmed that food trace-back processes and procedures could also work seamlessly in a feed contamination event.
The Michigan RRT investigated and took samples from farms and feed manufacturers that may have received the adulterated grease to ensure the recall was effective. The investigation findings impacted numerous feed manufacturers and producers in Michigan and were linked to approximately 55,000 turkey deaths, limited the movement of over 35,000 swine to market and resulted in the disposal of 500 tons of feed.
The case turned into a nationwide investigation and trace-back of a feed product involving FDA, U.S. Department of Agriculture and many other state feed and animal health programs. Due to the impact and scale of this event, the Michigan RRT set up a multidivisional Incident Management Team.
Dairy Dilemma: The Washington RRT’s Response to Contaminated Shake Mix
The RRT approach facilitates and encourages synergizing resources, streamlining actions and avoiding duplication. The Washington RRT has been dedicated in establishing relationships with partner agencies prior to an incident to expedite coordination when an event does occur. The benefit of maintaining these relationships and the synergy they produce were recently illustrated during a relatively large RRT-coordinated response when Washington State Department of Health epidemiologists were in contact with Washington State Department of Agriculture (WSDA) RRT, food safety and outreach/compliance contacts within hours of identifying an illness cluster preliminarily associated with a high-protein shake mix manufactured in the state.
RRT management at WSDA immediately notified RRT contacts at the FDA Seattle District Office, and a planning call was held to discuss sample results collected by county response partners and next steps. During the call, response staff identified a gap in the equipment needed to collect product samples and an immediate plan was implemented to leverage resources between the agencies to properly equip the field team.
Due to this expedited notification and coordination, a WSDA team was able to deploy to the facility that afternoon to conduct an on-site investigation and collect product and environmental samples. The needed equipment was identified during a postresponse hot wash, so those items will be available for future responses.
Upon receipt of preliminary sample results, WSDA and the FDA Seattle District Office deployed a joint WSDA/FDA operations group to the facility that afternoon to begin collecting records. Streamlined coordination also allowed for the rapid sharing of information related to the large voluntary recall, for which the FDA Seattle District Office served as the primary coordinating agency.
Due to the timing of this investigation, the RRT also had to quickly assess lab capacity over the December holiday season and work with state and federal agencies to share the sample analysis workload during a time when staff resources are typically limited. The processing facility investigation spanned 24 days from initial WSDA team deployment to observation of the firm’s corrective actions.
Given the scope of the facility investigation efforts, the Washington RRT established an Operations Section Chief position based at the company. This state employee served as the primary point of contact between the incident management team and the company management. The RRT noted in their hot wash that limiting the number of regulatory personnel directly working with company management appeared to free up the latter to address other duties related to overseeing their voluntary recall and facility upgrades. In addition, using a single regulatory contact reduced duplication in questions, records collected and reporting of information between the company and the response partners.
Overall, this incident emphasized the importance of using a coordinated response structure for sharing information and resources to effectively protect public health and mitigate potential economic impact. Ultimately, totes used to bring in fluid milk from a dairy supplier were identified as a possible contributing factor for contamination. The facility has since undergone thorough sanitization, installed new equipment and instituted new food safety policies, and has since resumed production.
These examples of RRTs in action demonstrate that RRTs can and do minimize the time between notification and containment of an outbreak. This pilot-turned-program demonstrates the power of leveraging resources across agencies to prevent illnesses and dampen economic impact of an outbreak.
“RRTs continue to be mentioned as an outstanding example of state and federal integration. Amazing things happen when creative individuals plan, train and work together on complex public health issues such as outbreaks,” says Jeff Farrar, director of Intergovernmental Relations and Partnerships for FDA’s Office of Foods and Veterinary Medicine. “Conversations start with ‘what if we’ instead of ‘that’s not how we have done it.’ The energy and enthusiasm within RRTs is contagious.”
The authors want to recognize the contributions that Lauren Yeung and Doug Karas, both of FDA, made to this article and thank all the contributing RRTs for sharing their work with a global audience.
Jennifer Pierquet, M.P.H., senior project manager, Minnesota Department of Agriculture, Dairy and Food Inspection Division.
Mark Buxton, M.A., RRT program manager, Missouri Department of Health and Senior Services.
Jessica Badour, recall outreach specialist, Georgia Department of Agriculture.
Ernie Julian, Ph.D., chief, Rhode Island Department of Health, Office of Food Protection.
Alida Sorenson, M.P.H., recall coordinator and RRT investigator, Minnesota Department of Agriculture, Dairy and Food Inspection Division.
Brian Sauders, Ph.D., RRT coordinator, New York State Department of Agriculture & Markets.
Reference
1. www.cdc.gov/parasites/cyclosporiasis/outbreaks/investigation-2013-epicurve.html.