Letters

Widespread Foodborne Cyclosporiasis trace-backs of raspberry shipments related to more than 25 of the events have indicated Outbreaks Present Major Challenges that the raspberries responsible were imported from Guatemala between early To the Editor: The organism now named May and mid-June 1996. cayetanensis was first recognized On June 17, 1996, CDC began hosting as a cause of human illness in 1977. For thrice-weekly conference calls to ensure several years, as its taxonomy was deliber- close coordination among CDC, the U.S. ated, it was referred to as “cyanobacterium-, and Drug Administration (FDA), and the or -like bodies” (CLBs), or considered many state and local health agencies to be blue-green algae. In 1993, C. investigating these widespread outbreaks cayetanensis was reported to be a protozoan and cases. The conference calls provided parasite, a coccidian member of the family coordination in tracking and discussing this Eimeriidae. To be infectious, the spherical, multifocal problem. In addition, on July 17, chlorine-resistant oocyst (8µm to 10µm) 1996, in Atlanta, CDC and FDA held a 1-day found in the feces of infected persons must work-shop entitled “cyclospora - 1996,” sporulate in the environment, a process which was attended by more than 80 persons that, depending on conditions, takes at least representing CDC, FDA, the U.S. Depart- several days. Upon examination by ultravio- ment of Agriculture, 16 states, one province, let microscopy, Cyclospora oocysts autofluo- five cities, five universities, the Council of resce and upon staining, they are variably State and Territorial Epidemiologists, the acid-fast. The incubation period between Association of State and Territorial Public infection and onset of symptoms averages Health Laboratory Directors, the Pan approximately 1 week. Cyclospora infects the American Health Organization, and the and usually causes watery government of Canada. The participants in , with frequent stools. It can also the investigations of Cyclospora shared the cause loss of appetite, weight loss, stomach knowledge gained through their individual cramps, nausea, vomiting, fatigue, increased investigations of this multistate, multicountry flatus, and low-grade fever. The duration of outbreak. The goals of the workshop were to symptoms is often several weeks, and begin to formulate effective prevention remitting courses spanning 1 to 2 months, strategies for Cyclospora infection, to dis- with several relapses, have been reported. cuss the strength of the evidence implicating Cyclosporiasis is effectively treated with Guatemalan raspberries, and to formulate trimethoprim/sulfamethoxazole; however, research needs. The workshop allowed for therapy for patients who are sulfa-intolerant discussions about the epidemiologic and has not been identified. trace-back studies conducted and specula- Before 1996, only three outbreaks of tion about where and how the raspberries Cyclospora infection had been reported in became contaminated. Representatives from the United States. However, between May 1 Texas, South Carolina, New York City, and mid-July 1996 almost 1,000 laboratory- Florida, and New Jersey presented data from confirmed cases were reported to the Centers their respective case-control and cohort for Disease Control and Prevention (CDC). A studies; CDC representatives provided an few hospitalizations (<20) were reported, but overview of the outbreaks and focused on no Cyclospora-related deaths were confirmed. multiple, specific trace-backs from more These infections occurred in at least 15 than 20 of the event-related outbreaks. FDA states and Canadian provinces and the representatives discussed their roles and District of Columbia. Investigations of regulatory authority in foodborne investiga- approximately 50 event-related outbreaks of tions. diarrheal illness due to C. cayetanensis, as The workshop also addressed the array of well as case-control studies of sporadic, scientific challenges concerning C. laboratory-confirmed cases by several states, cayetanensis, such as clinical diagnostic now clearly implicate consumption of fresh techniques, protocols for detection of the raspberries. Complete, high confidence level organism on produce, and the basic biology of

Emerging Infectious Diseases354 Vol. 2, No. 4—October-December 1996 Letters

this protozoon. We do not know the infectious exporter associations were most helpful in dose, the proportion of infected persons who the investigations and need to remain have diarrhea, the proportion of diarrheal involved if we are to better understand what illness caused in various settings by occurred in May and June of this year. Cyclospora, the existence of animal reser- Throughout the workshop, a wider issue voirs, or the viability of the organism in than the current situation with Cyclospora different environmental conditions. It can be was discussed: the management of the transmitted by water and food, and its emerging problem of widespread multistate transmission is seasonal (late spring/early and international foodborne outbreaks of summer), at least where it has been studied both infectious and toxic nature. Such (primarily temperate, seasonal climates). outbreaks are increasing and can be expected The poor sensitivity and specificity of to worsen as the world moves toward a global current methods for diagnosis and detection food economy. What contaminates a particu- of Cyclospora were discussed. A photomicro- lar food item on a farm, in a herd or crop, at a graphic demonstration convinced the partici- processing shed, or from a handler, can now pants that currently the foremost require- cause widely distributed outbreaks, conti- ment for accurate clinical diagnosis is a nents away, in a day. More coordination is skilled microscopist. The status of poly- needed on several fronts in the management merase chain reaction technologies for of such outbreaks: 1) the development of a detection and diagnosis of Cyclospora was structured process for integration and presented and discussed, including the coordination of epidemiologic studies; 2) inhibitory aspects of berry juices and the more aggressive laboratory diagnostic train- difficulty in oocyst recoveries from spiked ing related to poorly recognized or under- berry samples. Participants stated the need stood emerging infections; 3) better coordi- for a bank of Cyclospora organisms and their nation of press releases related to multistate DNA (molecular libraries) from different outbreaks; 4) better understanding and locations and outbreaks. Currently, we may clarification of the legal roles and responsi- not be able to take full advantage of such bilities of federal, state, and local agencies; epidemiologically well-documented speci- 5) and earlier involvement of industrial mens; however, the technologies and tools partners at all levels, including growing/ will continue to advance, and these speci- processing, exporting/importing, transport- mens need to be centrally banked now, to be ing, and wholesale/retail sales. Because made available when the tools are up to the these types of outbreaks are likely to become task. An animal model needs to be developed, international this aspect must be addressed or at least explored. The uses for such a in considering appropriate approaches. model include providing material (oocysts The Cyclospora outbreaks of May and and other life-cycle stages) for reagent June 1996 underlined that without the development (monoclonal antibodies) to ability to culture and grow the organisms, allow studies of the organisms, the disease, without a supply of the organism to develop immune responses, and potential environ- expedient assays, without an established mental transmission. Such a model will coordinating body to expedite agreed-upon facilitate the development of prevention and means for dissemination of information, we, treatment strategies. as public health officials, are called upon to Ongoing investigations into how the provide guidance without the benefit of all raspberries were contaminated were dis- the appropriate knowledge. The workshop cussed. The lack of sensitive and reproduc- engendered interchange and discussion on ible detection assays for Cyclospora, which critical issues concerning what is known and does not replicate outside the human host, unknown about Cyclospora and the out- remains the major stumbling block in breaks of cyclosporiasis during May and providing proof of contamination of sus- June 1996. The workshop also provided a pected transmission vehicles. Studies were forum in which it became apparent that too preliminary for conclusions. Both the public health officials must launch a government of Guatemala and the producer/ committed effort to develop an established,

Vol. 2, No. 4—October-December 1996 355 Emerging Infectious Diseases Letters

coordinating system among agencies at all by 1) characteristic morphology and size levels and deal with the threat of wide- (8µm to 10µm), 2) positive staining with spread, multistate/international foodborne Kinyoun’s acid-fast stain, 3) positive outbreaks caused by infectious or toxic autofluorescence under ultraviolet light, and agents. 4) sporulation of oocysts with formation of sporocysts after a 10-day incubation. All Daniel G. Colley these are diagnostic features of C. Centers for Disease Control and Prevention, cayetanensis (8) and to our knowledge are not Atlanta, Georgia, USA described for any known poultry coccidia. On the basis of these findings, we suggest that poultry may serve as a possible source for human infection with Cyclospora. Con- Identification of Cyclospora in Poultry sumption of chicken has been reported in one infected patient in the original description To the Editor: Human infection with the by Ashford (1) and in a patient reported parasitic , Cyclospora, was first recently by Connor and Shlim (9). Moreover, described in 1979 (1), and the organism was the only existing report of C. cayetanensis only recently categorized as an important found in feces from a domestic farm animal gastrointestinal parasite. A single species, concerned a farm duck (6). Zerpa et al. , has been described suggest that besides consumption of con- in humans (2), while most species in the taminated water, other modes of transmis- genus Cyclospora have been described only sion involving contact with domestic animals in reptiles and rodents (3). The consumption must be considered. So far, however, a of undercooked meat and exposure to possible infection route involving poultry, contaminated water have been considered whether it may be direct consumption of possible sources of human infection with C. undercooked chicken meat, contamination of cayetanensis (1,4). Coccidia were detected in food and water sources with chicken feces, or drinking water in Nepal (5), and the parasite both, remains to be determined. It should be was identified in an animal species (one duck noted that sanitary standards in poultry- in Peru, by Zerpa et al. [6]) different from breeding facilities in developing countries those in which it was described earlier. To may not be adequate. This would account for determine whether a domestic animal is the fact that reports implicating chickens in either a host or a reservoir for C. the transmission of Cyclospora (1,9) have cayetanensis, we first examined feces from occurred in, or in relation to, developing cats, which are hosts and reservoirs of countries. The Cyclospora found in the , a coccidia causing chickens in our study have the diagnostic human illness, but got negative results. features of C. cayetanensis. Nevertheless, Because Cyclospora were recently phyloge- the existence of another, not yet described, netically linked to Eimeria mitis and E. Cyclospora species infecting poultry, which tenella (7), coccidial parasites of chickens, we has similar features but is different from C. investigated the presence of Cyclospora in cayetanensis, cannot be excluded at this poultry. stage. In addition, the number of oocysts We pooled feces from approximately 600 recovered was not large and because feces 4- to 6-week-old chickens from a poultry farm were pooled, we could not calculate the near Monterrey, Mexico, and extracted feces number of oocysts passed by each bird. The from the caecum of 50 6- to 8-week-old possibility that oocysts were acquired as a chickens from a poultry market at that contaminant from food or water sources and location. By Percoll discontinuous-gradient were only passing though the gut of the centrifugation (Medina-De la Garza et al., chickens (making the chickens a paratonic submitted), both fecal pools were positive for host) cannot be ruled out. coccidia, mainly Eimeria species and what The increased recognition of Cyclospora we regarded as C. cayetanensis oocysts. as an important cause of diarrhea in both Presence of Cyclospora was confirmed immunocompromised and immunocompetent

Emerging Infectious Diseases356 Vol. 2, No. 4—October-December 1996