The impact of health communication and enhanced laboratory-based surveillance on detection of cyclosporiasis outbreaks in California

Identification of a Cyclospora cayetanensis Oocyst Antigens and Their Validity in the Detection of Immunogenic Patterns of Cyclosporiasis Patients

INTRODUCTION

The diagnosis of cyclosporiasis is currently based on the microscopic detection of oocysts, which may provide invalid results. The availability of simple, objective immunological screening tests would facilitate epidemiological studies of cyclosporiasis. Therefore, the present study aimed to identify the antigens of Cyclospora cayetanensis oocysts and their validity in serodiagnosis.

METHODS

According to parasitological and molecular diagnoses, three study groups were specified. Group (G) I included 30 patients with cyclosporiasis, GII included 12 patients with other parasitic infections, and GIII included 16 healthy subjects. SDS-PAGE was used to analyse C. cayetanensis antigens, and the validity of western blotting and enzyme-linked immunosorbent assays (ELISAs) was then assessed amongst the sera of all study groups.

RESULTS

The C. cayetanensis antigenic profile showed eight characteristic bands with molecular weights ranging from 14 to 175 kDa. Western blot analysis of sera revealed 93.3% (28/30 of GI) and 92.8% (26/28 of GII and III) sensitivity and specificity, respectively, dividing the patients in GI into four subgroups. The most frequent diagnostic bands (71.4% of GI sera) showed weights of 26-28 kDa, followed by 71 kDa (53.6%). ELISA sensitivity was 90% (27/30), and specificity was 78.6%. Validation showed perfect agreement between the PCR and western blot results, and ELISA presented substantial agreement with both the PCR and western blot results.

CONCLUSIONS

Our findings suggest the existence of high immunogenic diversity in C. cayetanensis and indicate that the 26-28 kDa immunogenic groups may potentially be used as a diagnostic marker of cyclosporiasis. Due to the high validity of ELISA, it might be the test of choice for the routine serodiagnosis of cyclosporiasis.

Update on Cyclospora cayetanensis, a food-borne and waterborne parasite

The coccidian parasite Cyclospora cayetanensis is recognized as an emerging pathogen that causes protracted diarrhea in humans. The first cases of Cyclospora infection were reported in the late 1970s and were observed among expatriates and travelers in regions where infections are endemic. Since then, Cyclospora has been considered a cause of traveler's diarrhea. Epidemiological investigations were reported and examined in areas of endemicity even before the true identity of Cyclospora was elucidated. Cyclospora was fully characterized in the early 1990s, but it was not until the 1995 Cyclospora outbreak in the United States and Canada that it caught the attention of the public and physicians. The biology, clinical presentation, epidemiology, diagnosis, treatment, and control of cyclosporiasis are reviewed, with a focus on diagnostic assays currently being used for clinical and environmental samples. Challenges and limitations in working with Cyclospora are also discussed.

Cyclosporiasis: an emerging public health concern around the world and in Africa

BACKGROUND

Cyclosporiasis is an emerging gastro-enteric disease caused by the coccidia protozoan Cyclospora cayetanensis. It is associated with diarrhoea among children in developing countries, in the Americas where C. cayetanensis is endemic, traveller's diarrhoea and/or food and waterborne outbreaks in the developed countries.

OBJECTIVES

The aim of this review is to highlight cyclosporiasis and its relevance to public health in East Africa and Africa at large.

METHODS

All literature on Cyclospora, C. cayetanensis, cyclosporiasis in Africa, and endemic cyclosporiasis was searched from libraries, colleagues and internet but only literature on its history, clinical presentation, epidemiology in endemic settings, and occurrence in Africa were scrutinised.

RESULTS

In Sub Saharan Africa, cyclosporiasis has been reported in at least 3 countries, including Tanzania, in East Africa, occurring in both immunocompromised and immunocompetent patients. Zoonotic species of Cyclospora have also been identified in East African primates, indicating likely endemicity of this little reported disease in the region. This can be attributed to lack of awareness in the public and medical profession concerning the disease, and therefore not routinely checked at the health centres. Cyclosporiasis is characterized by intermittent diarrhoea, and secondary conditions or sequelae such as reactive arthritis syndrome (Reiter's syndrome), have been associated with progression of the disease. Its management is based on antibiotics, an unusual scenario for a protozoa.

CONCLUSIONS

Although many aspects of this disease and its transmission remain an enigma, the situation has been rapidly changing since the disease first came to medical attention in the 1970s.

Communicating the risks of a new, emerging pathogen: the case of Cryptococcus gattii

The news media are an important channel for communicating public health messages, providing important information about geographic extent, symptoms, and precautionary measures. This function may be particularly important in the case of new and emerging infectious diseases, which are unfamiliar to both the public and health professionals. We conducted a content analysis of the coverage in six Canadian newspapers of two emerging infectious pathogens in British Columbia (BC), West Nile virus and Cryptococcus gattii (C. gattii), between 2001 and 2006. C. gattii was first identified in the Canadian Pacific Northwest in 1999, having previously been restricted to tropical and subtropical areas. By summer 2006, C. gattii had killed at least eight people and was responsible for over 150 hospitalizations in the province of BC, as well as significant morbidity and mortality among companion animals. West Nile virus reached Canada in 2001 and has since caused significant morbidity and mortality. It has not, to date, reached BC. Despite the much higher incidence of disease and death caused by C. gattii in BC, West Nile virus received five times more news coverage in the British Columbian and national newspapers examined. Surprisingly, the local newspaper closest to the center of the British Columbia C. gattii outbreak had a much lower proportion of coverage of the disease than other papers in the province. The article discusses possible explanations for these findings, and the implications for public health communication.

Bioterrorism and the people: how to vaccinate a city against panic

Bioterrorism policy discussions and response planning efforts have tended to discount the capacity of the public to participate in the response to an act of bioterrorism, or they have assumed that local populations would impede an effective response. Fears of mass panic and social disorder underlie this bias. Although it is not known how the population will react to an unprecedented act of bioterrorism, experience with natural and technological disasters and disease outbreaks indicates a pattern of generally effective and adaptive collective action. Failure to involve the public as a key partner in the medical and public-health response could hamper effective management of an epidemic and increase the likelihood of social disruption. Ultimately, actions taken by nonprofessional individuals and groups could have the greatest influence on the outcome of a bioterrorism event. Five guidelines for integrating the public into bioterrorism response planning are proposed: (1) treat the public as a capable ally in the response to an epidemic, (2) enlist civic organizations in practical public health activities, (3) anticipate the need for home-based patient care and infection control, (4) invest in public outreach and communication strategies, and (5) ensure that planning reflects the values and priorities of affected populations.

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.