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B L Herwaldt

Publications and source records attributed to B L Herwaldt.

At least 19 recordsLinked to original sources
PubMed2001

Outbreak of cyclosporiasis associated with basil in Missouri in 1999.

During the summer of 1999, an outbreak of cyclosporiasis occurred among attendees of 2 events held on 24 July in different counties in Missouri. We conducted retrospective cohort studies of the 2 clusters of cases, which comprised 62 case patients. The chicken pasta salad served at one event (relative risk [RR], 4.25; 95% confidence interval [CI], 1.80-10.01) and the tomato basil salad served at the other event (RR, 2.95; 95% CI, 1.72-5.07) were most strongly associated with illness. The most likely vehicle of infection was fresh basil, which was included in both salads and could have been grown either in Mexico or the United States. Leftover chicken pasta salad was found to be positive for Cyclospora DNA by means of polymerase chain reaction analysis, and 1 sporulated Cyclospora oocyst was found by use of microscopy. This is the second documented outbreak of cyclosporiasis in the United States linked to fresh basil and the first US outbreak for which Cyclospora has been detected in an epidemiologically implicated food item.

Adolescent↗
PubMed2001

Laboratory-acquired parasitic infections from accidental exposures.

Parasitic diseases are receiving increasing attention in developed countries in part because of their importance in travelers, immigrants, and immunocompromised persons. The main purpose of this review is to educate laboratorians, the primary readership, and health care workers, the secondary readership, about the potential hazards of handling specimens that contain viable parasites and about the diseases that can result. This is accomplished partly through discussion of the occupationally acquired cases of parasitic infections that have been reported, focusing for each case on the type of accident that resulted in infection, the length of the incubation period, the clinical manifestations that developed, and the means by which infection was detected. The article focuses on the cases of infection with the protozoa that cause leishmaniasis, malaria, toxoplasmosis, Chagas' disease (American trypanosomiasis), and African trypanosomiasis. Data about 164 such cases are discussed, as are data about cases caused by intestinal protozoa and by helminths. Of the 105 case-patients infected with blood and tissue protozoa who either recalled an accident or for whom the likely route of transmission could be presumed, 47 (44.8%) had percutaneous exposure via a contaminated needle or other sharp object. Some accidents were directly linked to poor laboratory practices (e.g., recapping a needle or working barehanded). To decrease the likelihood of accidental exposures, persons who could be exposed to pathogenic parasites must be thoroughly instructed in safety precautions before they begin to work and through ongoing training programs. Protocols should be provided for handling specimens that could contain viable organisms, using protective clothing and equipment, dealing with spills of infectious organisms, and responding to accidents. Special care should be exercised when using needles and other sharp objects.

Accidents, Occupational↗
PubMed2001

Multiyear prospective study of intestinal parasitism in a cohort of Peace Corps volunteers in Guatemala.

We conducted a prospective, longitudinal study in a cohort of 36 Peace Corps volunteers (PCVs) in Guatemala to study the incidence and natural history of intestinal parasitic infections during the PCVs' >2-year overseas stay. PCVs collected stool specimens at least monthly and when ill with gastrointestinal symptoms. Of the 1,168 specimens tested, 453 (38.8%) were positive for at least one parasite and 48 (4.1%) were positive for a pathogenic parasite. A median interval of 187 days (range, 14 to 752 days) elapsed before the first documented parasitic infection, and the median intervals from arrival until subsequent infections (e.g., second or third) were >300 days. The PCVs had 116 episodes of infection with 11 parasites, including up to 4 episodes per PCV with specific nonpathogens and Blastocystis hominis. The incidence, in episodes per 100 person-years, was highest for B. hominis (65), followed by Entamoeba coli (31), Cryptosporidium parvum (17), and Entamoeba hartmanni (17). The PCVs' B. hominis episodes lasted 6,809 person-days (28.7% of the 23,689 person-days in the study), the E. coli episodes lasted 2,055 person-days (8.7%), and each of the other types of episodes lasted <2% of the person-days in the study. Gastrointestinal symptoms were somewhat more common and more persistent, but not significantly so, in association with pathogen episodes than with B. hominis and nonpathogen episodes. Although infections with pathogenic parasites could account for only a minority of the PCVs' diarrheal episodes, the continued acquisition of parasitic infections throughout the PCVs' >2-year stay in Guatemala suggests that PCVs repeatedly had fecal exposures and thus were at risk for infections with both parasitic and nonparasitic pathogens throughout their overseas service.

Adult↗
PubMed2000

Cyclospora cayetanensis: a review, focusing on the outbreaks of cyclosporiasis in the 1990s.

Cyclospora cayetanensis, a coccidian parasite that causes protracted, relapsing gastroenteritis, has a short recorded history. In retrospect, the first 3 documented human cases of Cyclospora infection were diagnosed in 1977 and 1978. However, not much was published about the organism until the 1990s. One of the surprises has been the fact that a parasite that likely requires days to weeks outside the host to become infectious has repeatedly caused foodborne outbreaks, including large multistate outbreaks in the United States and Canada. In this review, I discuss what has been learned about this enigmatic parasite since its discovery and what some of the remaining questions are. My focus is the foodborne and waterborne outbreaks of cyclosporiasis that were documented from 1990 through 1999. The occurrence of the outbreaks highlights the need for health care personnel to consider that seemingly isolated cases of infection could be part of widespread outbreaks and should be reported to public health officials. Health care personnel should also be aware that stool specimens examined for ova and parasites usually are not examined for Cyclospora unless such testing is specifically requested and that Cyclospora infection is treatable with trimethoprim-sulfamethoxazole.

Animals↗
PubMed2000

A multiyear prospective study of the risk factors for and incidence of diarrheal illness in a cohort of Peace Corps volunteers in Guatemala.

BACKGROUND: Diarrheal illness is the most common medical disorder among travelers from developed to developing countries and is common among expatriate residents in developing countries. OBJECTIVE: To assess the risk factors for and incidence of diarrheal illness among Americans living in a developing country. DESIGN: Prospective longitudinal study. SETTING: Rural Guatemala. PATIENTS: Cohort of 36 Peace Corps volunteers. MEASUREMENTS: Collection of daily dietary and symptom data for more than 2 years; identification by multivariate Poisson regression analyses of risk factors for clinically defined episodes of diarrheal illness. RESULTS: The 36 Peace Corps volunteers in this study had 307 diarrheal episodes (median, 7 per person), which lasted a median of 4 days (range, 1 to 112) and a total of 10.1% of the 23 689 person-days in the study. The incidence density (episodes per person-year) was 4.7 for the study as a whole, 6.1 for the first 6-month period, 5.2 for the second 6-month period, and 3.6 thereafter. Statistically significant risk factors for diarrheal illness included drinking water whose source (for example, the tap) and, therefore, quality, was unknown to the person; eating food prepared by a Guatemalan friend or family; eating food at a small, working-class restaurant; eating fruit peeled by someone other than a Peace Corps volunteer; drinking an iced beverage; and eating ice cream, ice milk, or flavored ices. The relative risks comparing the presence of these exposures during the first 6-month period overseas with their absence during the second year of residence ranged from 1.90 to 2.67, and the summary attributable risk percentage (that is, the percentage of diarrheal episodes that could be ascribed to the exposures) was 75.4%. Exposures generally were riskier if they occurred during travel elsewhere in Guatemala rather than in the person's usual work area. CONCLUSIONS: Diarrheal illness of mild-to-moderate severity continued to occur throughout Peace Corps service but decreased in incidence as length of stay increased. Various dietary behaviors increased the risk for diarrheal illness, which suggests that avoidance of potentially risky foods and beverages is beneficial.

Adult↗
PubMed2000

Use of polymerase chain reaction to diagnose the fifth reported US case of autochthonous transmission of Trypanosoma cruzi, in Tennessee, 1998.

In July 1998, the mother of an 18-month-old boy in rural Tennessee found a triatomine bug in his crib, which she saved because it resembled a bug shown on a television program about insects that prey on mammals. The gut contents of the Triatoma sanguisuga were found, by light microscopy and polymerase chain reaction (PCR), to be infected with Trypanosoma cruzi; PCR products hybridized with T. cruzi-specific oligonucleotide probes. Whole-blood specimens obtained from the child in July and August were negative by buffy-coat examination and hemoculture but positive by PCR and DNA hybridization, suggesting that he had low-level parasitemia. Specimens obtained after treatment with benznidazole were negative. He did not develop anti-T. cruzi antibody; 19 relatives and neighbors also were seronegative. Two of 3 raccoons trapped in the vicinity had positive hemocultures for T. cruzi. The child's case of T. cruzi infection-the fifth reported US autochthonous case-would have been missed without his mother's attentiveness and the availability of sensitive molecular techniques.

Animals↗
PubMed1999

Leishmaniasis.

In 1903, Leishman and Donovan separately described the protozoan now called Leishmania donovani in splenic tissue from patients in India with the life-threatening disease now called visceral leishmaniasis. Almost a century later, many features of leishmaniasis and its major syndromes (ie, visceral, cutaneous, and mucosal) have remained the same; but also much has changed. As before, epidemics of this sandfly-borne disease occur periodically in India and elsewhere; but leishmaniasis has also emerged in new regions and settings, for example, as an AIDS-associated opportunistic infection. Diagnosis still typically relies on classic microbiological methods, but molecular-based approaches are being tested. Pentavalent antimony compounds have been the mainstay of antileishmanial therapy for half a century, but lipid formulations of amphotericin B (though expensive and administered parenterally) represent a major advance for treating visceral leishmaniasis. A pressing need is for the technological advances in the understanding of the immune response to leishmania and the pathogenesis of leishmaniasis to be translated into field-applicable and affordable methods for diagnosis, treatment, and prevention of this disease.

Amphotericin B↗
PubMed1999

A cluster of transfusion-associated babesiosis cases traced to a single asymptomatic donor.

CONTEXT: The risk of acquiring babesiosis by blood transfusion is largely unknown since in areas where it is endemic it is often an asymptomatic infection. OBJECTIVE: To investigate and treat a cluster of blood transfusion-associated babesiosis cases. DESIGN: Case series and epidemiologic investigation. SETTING: Urban inner-city hospital. PATIENTS: Six persons who received Babesia microti-infected blood components from a donor. MAIN OUTCOME MEASURE: Diagnosis and successful therapy of babesiosis following transfusion. RESULTS: Six individuals (1 adult, 1 child, and 4 neonates) were exposed to products from a single blood donation by an asymptomatic Babesia-infected donor. Three of the 6 exposed patients became parasitemic. Polymerase chain reaction testing, animal inoculation studies, and indirect immunofluorescent antibody testing were used to confirm the presence of Babesia microti in the donor's blood and to establish the presence of infection in 3 of the 6 recipients. The 3 infected recipients and 1 additional recipient were treated without incident. CONCLUSION: Physicians should consider babesiosis in the differential diagnosis of a febrile hemolytic disorder after blood transfusion. Prompt diagnosis is important since babesiosis is responsive to antibiotic therapy and, untreated, can be a fatal disease in certain risk groups.

Aged↗
PubMed1999

The return of Cyclospora in 1997: another outbreak of cyclosporiasis in North America associated with imported raspberries. Cyclospora Working Group.

BACKGROUND: In the spring of 1996, an outbreak of cyclosporiasis associated with fresh Guatemalan raspberries occurred in the United States and Canada. Another multistate outbreak of cyclosporiasis occurred in North America in the spring of 1997. OBJECTIVE: To identify the vehicle of the outbreak that occurred in the spring of 1997. DESIGN: Retrospective cohort studies of clusters of cases associated with events (such as banquets) and traceback investigations of sources of implicated produce. SETTING: United States and Canada. PATIENTS: Persons who attended events associated with clusters of cases of cyclosporiasis. MEASUREMENTS: Identification of clinically defined or laboratory-confirmed cases of cyclosporiasis and risk factors for infection. RESULTS: 41 clusters of cases were reported in association with events held from 1 April through 26 May in 13 U.S. states, the District of Columbia, and 1 Canadian province. The clusters comprised 762 cases of cyclosporiasis, 192 (25.2%) of which were laboratory confirmed. In addition, 250 laboratory-confirmed sporadic cases were reported in persons who developed gastrointestinal symptoms from April through 15 June, for a total of 1012 cases. Fresh raspberries were the only food common to all 41 events and were the only type of berry served at 9 events (22.0%). Statistically significant associations between consumption of raspberry-containing items and cyclosporiasis were documented for 15 events (40.5% of 37). For 31 of the 33 events with well-documented traceback data, the raspberries either definitely came from Guatemala (8 events) or could have come from Guatemala (23 events). The mode of contamination of the raspberries remains unknown. The outbreak ended shortly after the exportation of fresh raspberries from Guatemala was voluntarily suspended at the end of May 1997. CONCLUSIONS: Similar multistate, multicluster outbreaks of cyclosporiasis associated with consumption of Guatemalan raspberries have occurred in consecutive years. These outbreaks highlight the need for better understanding of the biology and epidemiology of Cyclospora cayetanensis and for stronger prevention and control measures to ensure the safety of produce eaten raw.

Animals↗
PubMed1998

Surveillance for waterborne-disease outbreaks--United States, 1995-1996.

PROBLEM/CONDITION: Since 1971, CDC and the U.S. Environmental Protection Agency have maintained a collaborative surveillance system for collecting and periodically reporting data that relate to occurrences and causes of waterborne-disease outbreaks (WBDOs). REPORTING PERIOD COVERED: This summary includes data for January 1995 through December 1996 and previously unreported outbreaks in 1994. DESCRIPTION OF THE SYSTEM: The surveillance system includes data about outbreaks associated with drinking water and recreational water. State, territorial, and local public health departments are primarily responsible for detecting and investigating WBDOs and for voluntarily reporting them to CDC on a standard form. RESULTS: For the period 1995-1996, 13 states reported a total of 22 outbreaks associated with drinking water. These outbreaks caused an estimated total of 2,567 persons to become ill. No deaths were reported. The microbe or chemical that caused the outbreak was identified for 14 (63.6%) of the 22 outbreaks. Giardia lamblia and Shigella sonnei each caused two (9.1%) of the 22 outbreaks; Escherichia coli O157:H7, Plesiomonas shigelloides, and a small round structured virus were implicated for one outbreak (4.5%) each. One of the two outbreaks of giardiasis involved the largest number of cases, with an estimated 1,449 ill persons. Seven outbreaks (31.8% of 22) of chemical poisoning, which involved a total of 90 persons, were reported. Copper and nitrite were associated with two outbreaks (9.1% of 22) each and sodium hydroxide, chlorine, and concentrated liquid soap with one outbreak (4.5%) each. Eleven (50.0%) of the 22 outbreaks were linked to well water, eight in noncommunity and three in community systems. Only three of the 10 outbreaks associated with community water systems were caused by problems at water treatment plants; the other seven resulted from problems in the water distribution systems and plumbing of individual facilities (e.g., a restaurant). Six of the seven outbreaks were associated with chemical contamination of the drinking water; the seventh outbreak was attributed to a small round structured virus. Four of the seven outbreaks occurred because of backflow or backsiphonage through a cross-connection, and two occurred because of high levels of copper that leached into water after the installation of new plumbing. For three of the four outbreaks caused by contamination from a cross-connection, an improperly installed vacuum breaker or a faulty backflow prevention device was identified; no protection against backsiphonage was found for the fourth outbreak. Thirty-seven outbreaks from 17 states were attributed to recreational water exposure and affected an estimated 9,129 persons, including 8,449 persons in two large outbreaks of cryptosporidiosis. Twenty-two (59.5%) of these 37 were outbreaks of gastroenteritis; nine (24.3%) were outbreaks of dermatitis; and six (16.2%) were single cases of primary amebic meningoencephalitis caused by Naegleria fowleri, all of which were fatal. The etiologic agent was identified for 33 (89.2%) of the 37 outbreaks. Six (27.3%) of the 22 outbreaks of gastroenteritis were caused by Cryptosporidium parvum and six (27.3%) by E. coli O157:H7. All of the latter were associated with unchlorinated water (i.e., in lakes) or inadequately chlorinated water (i.e., in a pool). Thirteen (59.1%) of these 22 outbreaks were associated with lake water, eight (36.4%) with swimming or wading pools, and one(4.5%) with a hot spring. Of the nine outbreaks of dermatitis, seven (77.8%) were outbreaks of Pseudomonas dermatitis associated with hot tubs, and two (22.2%) were lake-associated outbreaks of swimmer's itch caused by Schistosoma species. INTERPRETATION: WBDOs caused by E. coli O157:H7 were reported more frequently than in previous years and were associated primarily with recreational lake water. This finding suggests the need for better monitoring of water quality and identification of sources of

Communicable Disease Control↗
PubMed1998

Chronic multisymptom illness affecting Air Force veterans of the Gulf War.

CONTEXT: Gulf War (GW) veterans report nonspecific symptoms significantly more often than their nondeployed peers. However, no specific disorder has been identified, and the etiologic basis and clinical significance of their symptoms remain unclear. OBJECTIVES: To organize symptoms reported by US Air Force GW veterans into a case definition, to characterize clinical features, and to evaluate risk factors. DESIGN: Cross-sectional population survey of individual characteristics and symptoms and clinical evaluation (including a structured interview, the Medical Outcomes Study Short Form 36, psychiatric screening, physical examination, clinical laboratory tests, and serologic assays for antibodies against viruses, rickettsia, parasites, and bacteria) conducted in 1995. PARTICIPANTS AND SETTING: The cross-sectional questionnaire survey included 3723 currently active volunteers, irrespective of health status or GW participation, from 4 air force populations. The cross-sectional clinical evaluation included 158 GW veterans from one unit, irrespective of health status. MAIN OUTCOME MEASURES: Symptom-based case definition; case prevalence rate for GW veterans and nondeployed personnel; clinical and laboratory findings among veterans who met the case definition. RESULTS: We defined a case as having 1 or more chronic symptoms from at least 2 of 3 categories (fatigue, mood-cognition, and musculoskeletal). The prevalence of mild-to-moderate and severe cases was 39% and 6%, respectively, among 1155 GW veterans compared with 14% and 0.7% among 2520 nondeployed personnel. Illness was not associated with time or place of deployment or with duties during the war. Fifty-nine clinically evaluated GW veterans (37%) were noncases, 86 (54%) mild-to-moderate cases, and 13 (8%) severe cases. Although no physical examination, laboratory, or serologic findings identified cases, veterans who met the case definition had significantly diminished functioning and well-being. CONCLUSIONS: Among currently active members of 4 Air Force populations, a chronic multisymptom condition was significantly associated with deployment to the GW. The condition was not associated with specific GW exposures and also affected nondeployed personnel.

Adult↗
PubMed1998

Cyclospora.

Although Cyclospora infection has been documented in humans worldwide since at least 1977, it is only in the past 2 years that this organism has come into prominence as a result of major foodborne outbreaks in the United States and Canada. Cyclospora causes significant gastrointestinal disease in immunocompetent and immunocompromised hosts and can be successfully treated with trimethoprim-sulfamethoxazole. The infection is under-recognized because our methods for diagnosis are rudimentary and insensitive. The mechanisms by which the parasite causes disease, the range of animal hosts, and the natural reservoir are unknown. Cyclospora is a unique coccidian parasite that has just begun to emerge; as yet, we have no clue as to where it comes from or where it hides.

Animals↗
PubMed1998

First reported outbreak in the United States of cryptosporidiosis associated with a recreational lake.

In the summer of 1994, an outbreak of cryptosporidiosis occurred among visitors to a state park in New Jersey. We enrolled 185 persons in a cohort study, 38 (20.5%) of whom had laboratory-confirmed cryptosporidiosis or gastrointestinal illness that met our clinical case definition. Having any exposure to lake water (e.g., swimming) was strongly associated with illness (P < .001). The outbreak lasted 4 weeks and affected an estimated 2,070 persons. The most likely sources of the outbreak were contaminated runoff of rainwater and infected bathers. This outbreak of cryptosporidiosis is the first reported to be associated with recreational exposure to lake water. Our investigation shows that even a large and ongoing outbreak may not be detected for several weeks. Health professionals and persons at high risk for severe cryptosporidiosis should be aware that recreational water can be a source of cryptosporidium infection.

Adolescent↗
PubMed1998

First reported outbreak of abdominal angiostrongyliasis.

Human abdominal angiostrongyliasis is a potentially fatal disease caused by Angiostrongylus costaricensis, a nematode found in the Americas. During the period of December 1994 through August 1995, an outbreak of this disease occurred in Guatemala. We identified 22 cases of abdominal angiostrongyliasis and conducted a matched case-control study to identify risk factors for illness. The median age of the 18 cases enrolled in the study was 37 years (range, 9-68 years), and 11 (61.1%) were male. Consumption of the following six raw food items was associated with angiostrongyliasis: mint (odds ratio [OR], 6.9; 95% confidence interval [CI], 1.5-66.0), shrimp (OR, infinite; 95% CI, 1.4 to infinite), and four kinds of ceviche that reportedly contained raw mint (OR for consumption of mint or ceviche that contained mint, 7.0; 95% CI, 1.0-315). We conclude that raw mint was the likely vehicle of infection for this outbreak. To our knowledge, this is the first reported outbreak of abdominal angiostrongyliasis and the first time that a specific food item has been epidemiologically linked to the disease.

Abdomen↗
PubMed1998

An outbreak of cyclosporiasis in Florida in 1995: a harbinger of multistate outbreaks in 1996 and 1997.

Before 1995, only one outbreak of cyclosporiasis had been reported in the United States. To identify risk factors for Cyclospora infection acquired in Florida in 1995, we conducted a matched case-control study (24 sporadic cases and 69 controls) and retrospective cohort studies of clusters of cases associated with two May social events (attack rates = 15.4% [8 of 52] and 54.5% [6 of 11]). In univariate analysis of data from the case-control study, consumption of fresh raspberries (odds ratio [OR] = 6.0, 95% confidence interval [CI] = 1.1-31.7) and bare-handed contact with soil (OR = 5.4, 95% CI = 1.4-20.7) were associated with infection; soil contact was also implicated in multivariate analysis. For the events, mixed-fruit items that had only fresh raspberries and strawberries in common had elevated relative risks (3.7 and 4.2), but the confidence intervals overlapped 1.0. The raspberries eaten at the events and by sporadic case-patients were imported. Given the cumulative evidence of the three studies and the occurrence in 1996 and 1997 of outbreaks in North America associated with consumption of Guatemalan raspberries, food-borne transmission of Cyclospora was likely in 1995 in Florida as well.

Adolescent↗
PubMed1998

A foodborne outbreak of cyclosporiasis caused by imported raspberries.

BACKGROUND: Cyclospora cayetanensis is a recently recognized parasite that causes prolonged diarrheal illness. Its modes of transmission have not been fully determined, although some investigations before 1996 implicated water. Outbreaks of cyclosporiasis in the United States in 1996 and 1997 are evidence of the increasing incidence of this disease. This report describes an outbreak of cyclosporiasis in persons who attended a luncheon on May 23, 1996, near Charleston, South Carolina. METHODS: In this retrospective cohort study, we interviewed all 64 luncheon attendees and the chef regarding food and beverage exposures. A case of cyclosporiasis was defined as diarrhea (> or = 3 loose stools per day or > or = 2 loose stools per day if using antimotility drugs) after attending the luncheon. We identified sporadic cases of cyclosporiasis and traced the implicated food. RESULTS: Of 64 luncheon attendees, 38 (59%) met the case definition. Persons who ate raspberries (relative risk [RR] = 5.4; 95% confidence interval [CI], 2.2-13.2) or potato salad (RR = 1.8; 95% CI, 1.2-2.6) were at significantly increased risk for illness. The population attributable risk percentages were 73% for raspberries and 20% for potato salad. Cyclospora oocysts were found in stools from 11 (85%) of the 13 case patients submitting specimens for testing. Implicated raspberries originated in Guatemala. CONCLUSIONS: Our investigation is one of the first studies to implicate a specific food (raspberries) as a vehicle for transmission of Cyclospora. Because of the apparent increasing incidence of cyclosporiasis in the United States, family physicians should consider testing for Cyclospora in any patient with prolonged, unexplained diarrhea.

Adult↗
PubMed1997

An outbreak in 1996 of cyclosporiasis associated with imported raspberries. The Cyclospora Working Group.

BACKGROUND: Cyclospora cayetanensis is a parasite that causes gastroenteritis. Until last year most of the documented cases of cyclosporiasis in North America were in overseas travelers. In 1996, a large outbreak of cyclosporiasis occurred in North America. We investigated this outbreak. METHODS: Health departments solicited information from clinicians and laboratories on cases of cyclosporiasis, which were then reported to the Centers for Disease Control and Prevention and to Health Canada. We conducted retrospective cohort studies for the cases associated with events (e.g., luncheons) and attempted to identify the sources of the implicated food. RESULTS: A total of 1465 cases of cyclosporiasis were reported by 20 states, the District of Columbia, and 2 provinces. Of these cases, 978 (66.8 percent) were laboratory confirmed and 725 (49.5 percent) were associated with 55 events that were held from May 3 through June 14. Raspberries were definitely served at 50 events and may have been served at 4 events. For 27 of the 41 events for which adequate data were available (65.8 percent), the associations between the consumption of berries (raspberries with or without other berries) and cyclosporiasis were statistically significant (P<0.05). For all 29 events for which there were good data, the raspberries definitely came from Guatemala (21 events, 72.4 percent) or may have come from Guatemala (8 events, 27.6 percent). As few as five Guatemalan farms could have accounted for the 25 events for which the raspberries could be traced to a single exporter per event. The mode of contamination of the raspberries remains unclear. CONCLUSIONS: This large outbreak of cyclosporiasis in North America in 1996 was associated with the consumption of Guatemalan raspberries. The outbreak illustrates the need to consider that a local cluster of foodborne illness may be part of a widespread outbreak and to pursue investigations to the source of the implicated vehicle.

Adolescent↗