Cyclosporiasis associated with imported raspberries, Florida, 1996

Sources and Prevalence of Cyclospora cayetanensis in Southeastern U.S. Growing Environments

Recent cyclosporiasis outbreaks associated with fresh produce grown in the United States highlight the need to better understand Cyclospora cayetanensis prevalence in U.S. agricultural environments. In this study, C. cayetanensis occurrence was assessed in municipal wastewater sludge, on-farm portable toilets, irrigation pond water, and spent packing house dump tank water in a Southeastern Georgia growing region over two years. Detection of the C. cayetanensis 18S rRNA qPCR gene target in pond samples was 0%, 28%, and 42% (N = 217) depending on the detection definition used, and ≤1% in dump tank samples (N = 46). However, no qPCR detections were confirmed by sequencing, suggesting false detection occurred due to cross-reactions. C. cayetanensis qPCR detections were confirmed in 9% of wastewater sludge samples (N = 76). The human-specific fecal markers HF183 and crAssphage were detected in 33% and 6% of pond samples, respectively, and 4% and 0% of dump tank samples, respectively. Despite community Cyclospora shedding and evidence of human fecal contamination in irrigation water, there was no correlation between C. cayetanensis and HF183 qPCR detections, further supporting that 18S gene target qPCR amplifications were due to cross-reactions. When evaluating C. cayetanensis qPCR environmental detection data, the impact of assay specificity and detection criteria should be considered. Moreover, additional sequence-based testing may be needed to appropriately interpret Cyclospora qPCR environmental data.

Cyclospora cayetanensis and Cyclosporiasis: An Update

Cyclospora cayetanensis is a coccidian parasite of humans, with a direct fecal-oral transmission cycle. It is globally distributed and an important cause of foodborne outbreaks of enteric disease in many developed countries, mostly associated with the consumption of contaminated fresh produce. Because oocysts are excreted unsporulated and need to sporulate in the environment, direct person-to-person transmission is unlikely. Infection by C. cayetanensis is remarkably seasonal worldwide, although it varies by geographical regions. Most susceptible populations are children, foreigners, and immunocompromised patients in endemic countries, while in industrialized countries, C. cayetanensis affects people of any age. The risk of infection in developed countries is associated with travel to endemic areas and the domestic consumption of contaminated food, mainly fresh produce imported from endemic regions. Water and soil contaminated with fecal matter may act as a vehicle of transmission for C. cayetanensis infection. The disease is self-limiting in most immunocompetent patients, but it may present as a severe, protracted or chronic diarrhea in some cases, and may colonize extra-intestinal organs in immunocompromised patients. Trimetoprim-sulfamethoxazole is the antibiotic of choice for the treatment of cyclosporiasis, but relapses may occur. Further research is needed to understand many unknown epidemiological aspects of this parasitic disease. Here, we summarize the biology, epidemiology, outbreaks, clinical symptoms, diagnosis, treatment, control and prevention of C. cayetanensis; additionally, we outline future research needs for this parasite.

Cyclospora cayetanensis in a pediatric hospital in Morelia, México

Cyclospora cayetanensis, a coccidian parasite, can cause gastrointestinal illness in humans and is characterized by watery and persistent diarrhea and abdominal pain. Cyclosporiasis has been associated with traveler's diarrhea. The infection is acquired through food and waterborne transmission, particularly by consumption of contaminated fresh fruits and vegetables. In the present study, stool samples from 8,877 children were examined for ova and parasites at the Pediatric Hospital of Morelia in Michoacán, Mexico, during 2000-2009. Sixty children (0.67%) had Cyclospora in their stools. Diarrhea (45.8%), abdominal pain (39.6%), and vomiting (18.8%) were the most frequent symptoms of cases with cyclosporiasis. Most of the cases (93.3%) were observed during June-August, the rainy season. In 45 children, Cyclospora was the only parasitic pathogen detected (75%); 15 children were co-infected with commensal, pathogenic, or both groups of parasites. Our findings suggest that C. cayetanensis is endemic to Michoacán and shows characteristically temporal patterns.

Análise de Risco aplicada aos alimentos no Brasil: perspectivas e desafios

Trata-se de um estudo de caso no qual se discutiram as ideias do Comitê do Codex Alimentarius do Brasil (CCAB), coordenado pelo Instituto Nacional de Metrologia, Normalização e Qualidade Industrial (Inmetro) sobre a norma Codex Alimentarius de Análise de Risco aplicada aos alimentos (AR). Os objetivos deste trabalho foram identificar e analisar a opinião dos membros do CCAB sobre AR e levantar as propostas para a adoção desta norma no país, destacando as limitações e as potencialidades locais apontadas. Os membros do CCAB mostraram-se favoráveis à iniciativa do Codex em instituir a norma AR para promover a segurança sanitária dos alimentos que transitam no mercado internacional. Houve concordância no sentido de que o governo brasileiro deva incorporar a AR como política oficial para melhorar o sistema de controle de alimentos do país e para fortalecer as exportações brasileiras de alimentos. Reconheceram que o Brasil dispõe de capacidade técnico-científica para aplicar essa norma, porém destacaram várias limitações político-institucionais. Os membros reconhecem a AR como uma iniciativa valiosa para enfrentar os riscos dos alimentos, devido a sua capacidade de aprimorar as ações de controle sanitário de alimentos realizadas pelo governo.

Diagnosis and treatment of acute or persistent diarrhea

Studies of microbial pathogens and the toxins they produce are important for determining the mechanisms by which they cause disease and spread throughout a population. Some bacteria produce secretory enterotoxins (such as cholera toxin or the heat-labile or stable enterotoxins produced by Escherichia coli) that invade cells directly. Others invade cells or produce cytotoxins (such as those produced by Shigella, enteroinvasive E coli, or Clostridium difficile) that damage cells or trigger host responses that cause small or large bowel diseases (such as enteroaggregative or enteropathogenic E coli or Salmonella). Viruses (such as noroviruses and rotaviruses) and protozoa (such as Cryptosporidium, Giardia, or Entamoeba histolytica) disrupt cell functions and cause short- or long-term disease. Much epidemiologic data about these pathogens have been collected from community- and hospital-acquired settings, as well as from patients with traveler's or persistent diarrhea. These studies have led to practical approaches for prevention, diagnosis, and treatment.

Efficacy of gaseous chlorine dioxide as a sanitizer against Cryptosporidium parvum, Cyclospora cayetanensis, and Encephalitozoon intestinalis on produce

The efficacy of gaseous chlorine dioxide to reduce parasite and bacterial burden in produce was studied. Basil and lettuce leaves were inoculated with Cryptosporidium parvum and Cyclospora cayetanensis oocysts, Encephalitozoon intestinalis spores, and a cocktail of two isolates of nalidixic acid-resistant Escherichia coli O157:H7. The inoculated samples were then treated for 20 min with gaseous chlorine dioxide at 4.1 mg/liter. Cryptosporidium had a 2.6 and 3.31 most-probable-number log reduction in basil and lettuce, respectively. Reduction of Encephalitozoon in basil and lettuce was 3.58 and 4.58 CFU/g respectively. E. coli loads were significantly reduced (2.45 to 3.97 log), whereas Cyclospora sporulation was not affected by this treatment.

Evaluation of field training in the epidemic intelligence service: publications and job choices

BACKGROUND

Since 1951, the Centers for Disease Control and Prevention's Epidemic Intelligence Service (EIS) has provided training in applied epidemiology to physicians, nurses, veterinarians, dentists, and doctoral-level health scientists. About one third of these EIS officers have been trained in the setting of state and local health departments (the field).

METHODS

To evaluate two specific outcomes of field EIS training, the authors reviewed the published work and career choices of field EIS officers after completing the program. The EIS classes of 1991-1996 were selected for study. A field officer was defined as an EIS Officer who completed at least the second year of a 2-year EIS assignment in a state or local health department position.

RESULTS

During this period, 430 EIS officers completed the program; 117 (27.2%) were field officers. Of these, 84 (71.8%) published one or more scientific paper as first author for a total of 202 first authored manuscripts in over 50 different journals, an average of 1.7 (range, 0-8) per officer. Most (71%) were on infectious disease topics; 16% were on environmental health or injury control topics, and 11% were on chronic diseases. Field officers were more likely than headquarters-based officers to choose positions in state or local health departments for their first job after graduating (32/117 [27.4%] versus 22/313 [7.0%]; relative risk = 3.9, 95% confidence interval = 2.4-6.4).

CONCLUSIONS

EIS training in the field has contributed to the scientific literature and to the strengthening of public health infrastructure at the state and local level.

Effects of pesticides on sporulation of Cyclospora cayetanensis and viability of Cryptosporidium parvum

Disease outbreaks caused by the coccidian parasite Cyclospora cayetanensis in food have been linked to consumption of raspberries that may have been contaminated through exposure to water mixed with insecticides and fungicides that may have been sprayed onto the berries. Three different fungicides (captan 50% W.P., benomyl 50% W.P., and zineb 75% W.P.) and two different insecticides (malathion 25% W.P. and diazinon 4E 47.5%) were evaluated at five different concentrations and for exposure times of 30 min to 1 week. Sporulation of C. cayetanensis did not decrease with use of any of the pesticides from time periods of 30 min to 24 h at all concentrations. Sporulation percentage was reduced with the fungicide benomyl at 1 week of exposure. The growth of the parasite Cryptosporidium parvum was also evaluated using captan 50% W.P., benomyl 50% W.P., and diazinon 4E 47.5%. Oocyst infectivity was reduced only after 7 days of exposure. These results indicate that these pesticides used at recommended concentration levels do not affect the sporulation of Cyclospora.

Intestinal coccidia in Cuban pediatric patients with diarrhea

From May to August 1999, we evaluated 401 patients from a pediatric hospital of Havana City. One group was composed of 113 patients with diarrhea admitted to the Gastroenterology ward and a second consisted of 288 patients without diarrhea, admitted for other reasons, and hospitalized within the same time period. Three stool samples were collected from each child and were examined using three parasitological techniques. When we compared the frequency of parasite species between both groups, we found Cryptosporidium spp. and Cyclospora cayetanensis, only in the group of children with diarrhea (P < 0.01). However, no significant differences were found in the occurrence of the other intestinal parasites (P > 0.05). In addition, in those children infected with Cryptosporidium, the diarrhea had a more prolonged duration (P < 0.01), while those infected with Cyclospora, the abdominal cramps or pain, and acute diarrhea were more frequently detected (P < 0.01). Our results showed that emerging intestinal coccidia are pathogens strongly associated in this group of children with diarrhea.

Epidemiologic clues to bioterrorism

Public health investigators have successfully carried out epidemiologic investigations of outbreaks of disease for many years. By far the majority of these outbreaks have occurred naturally. With the recent illnesses resulting from deliberate dissemination of B. anthracis on an unsuspecting population, public health investigation of diseases must now include consideration of bioterrorism as a potential cause of outbreaks of disease. The features of naturally occurring outbreaks have a certain amount of predictability in terms of consistency with previous occurrences, or at least biological plausibility. However, with a deliberately introduced outbreak or infection among a population, this predictability is minimized. In this paper, the authors propose some epidemiologic clues that highlight features of outbreaks that may be suggestive of bioterrorism. They also describe briefly the general process of involvement of agencies at various levels of government, public health and non-public health, depending on the extent of an outbreak or level of suspicion.

Emerging and reemerging intestinal protozoa

The intestinal protozoa have gained importance to physicians practicing medicine in the United States, Canada, and Europe during recent years as a result of increasing world travel, the globalization of the world's economy, and the growing number of chronically immunosuppressed people. During the spring of 1996, Cyclospora cayetanensis caused diarrhea in approximately 1500 people exposed to Guatemalan raspberries. This epidemic recurred in 1997, emphasizing the risks of the global economy and food supply on which we depend. In addition to importation of intestinal protozoa from the tropics, AIDS and the increasing use of organ transplants have created a new population of people at risk for chronic infection by ubiquitous protozoa previously not known to cause serious human disease. These infections include cryptosporidiosis, isosporiasis, and microsporidiosis. Finally, Entamoeba histolytica, the etiologic agent of invasive amebiasis, has only recently been recognized to be a distinct species from a nonpathogenic but indistinguishable (by light microscopy) intestinal commensal, Entamoeba dispar. The rapidly changing epidemiology of these intestinal protozoa, as well as new approaches to diagnosis and treatment of these protozoa, are discussed.

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.