Detection of Cryptosporidium and Cyclospora Oocysts from Environmental Water for Drinking and Recreational Activities in Sarawak, Malaysia

Cryptosporidiosis and cyclosporiasis are caused by waterborne coccidian protozoan parasites of the genera Cryptosporidium and Cyclospora, respectively. This study was conducted to detect Cryptosporidium and Cyclospora oocysts from environmental water abstracted by drinking water treatment plants and recreational activities in Sarawak, Malaysia. Water samples (12 each) were collected from Sungai Sarawak Kanan in Bau and Sungai Sarawak Kiri in Batu Kitang, respectively. In addition, 6 water samples each were collected from Ranchan Recreational Park and UNIMAS Lake at Universiti Malaysia Sarawak, Kota Samarahan, respectively. Water physicochemical parameters were also recorded. All samples were concentrated by the iron sulfate flocculation method followed by the sucrose floatation technique. Cryptosporidium and Cyclospora were detected by modified Ziehl-Neelsen technique. Correlation of the parasites distribution with water physicochemical parameters was analysed using bivariate Pearson correlation. Based on the 24 total samples of environmental water abstracted by drinking water treatment plants, all the samples (24/24; 100%) were positive with Cryptosporidium, and only 2 samples (2/24; 8.33%) were positive with Cyclospora. Based on the 12 total samples of water for recreational activities, 4 samples (4/12; 33%) were positive with Cryptosporidium, while 2 samples (2/12; 17%) were positive with Cyclospora. Cryptosporidium oocysts were negatively correlated with dissolved oxygen (DO).

Enteric protozoa in the developed world: a public health perspective

Several enteric protozoa cause severe morbidity and mortality in both humans and animals worldwide. In developed settings, enteric protozoa are often ignored as a cause of diarrheal illness due to better hygiene conditions, and as such, very little effort is used toward laboratory diagnosis. Although these protozoa contribute to the high burden of infectious diseases, estimates of their true prevalence are sometimes affected by the lack of sensitive diagnostic techniques to detect them in clinical and environmental specimens. Despite recent advances in the epidemiology, molecular biology, and treatment of protozoan illnesses, gaps in knowledge still exist, requiring further research. There is evidence that climate-related changes will contribute to their burden due to displacement of ecosystems and human and animal populations, increases in atmospheric temperature, flooding and other environmental conditions suitable for transmission, and the need for the reuse of alternative water sources to meet growing population needs. This review discusses the common enteric protozoa from a public health perspective, highlighting their epidemiology, modes of transmission, prevention, and control. It also discusses the potential impact of climate changes on their epidemiology and the issues surrounding waterborne transmission and suggests a multidisciplinary approach to their prevention and control.

[Cyclospora cayetanensis: biology, environmental distribution and transfer]

Cyclospora cayetanensis is an apicomplexan protozoan that has emerged as an important pathogen causing endemic or epidemic diarrheal disease worldwide. In industrialized countries, the parasite has been recognized as the causative agent of several outbreaks of diarrheal illness mostly associated with produce imported from endemic areas. In developing countries, human cyclosporosis is widely distributed. Infection rates from 0% to 41.6% have been described in the general population. However, the epidemiology, biology, and ecology of C. cayetanensis are not fully understood. The life cycle is not completely characterized, although it appears to require a single human host to be accomplished. The role of animals as natural reservoirs of the parasite remains to be determined. Little information is available concerning the environmental distribution and vehicles of transmission of C. cayetanensis. Contaminated water, foods or soil can be vehicles of spread of the parasite. The significant uncertainties that remain in the knowledge of C. cayetanensis highlight the need for continuing research in several areas, including its basic biology and environmental distribution.

Travelers' diarrhea in Nepal: an update on the pathogens and antibiotic resistance

BACKGROUND

Diarrhea is the most common illness among travelers and expatriates in Nepal. Published data on the etiology of travelers' diarrhea (TD) in Nepal are over 13 years old and no prior data exist on antibiotic susceptibility for currently used drugs. We investigated the etiology of diarrhea and antimicrobial susceptibility pattern of bacterial pathogens and compared the results to previous work from the same clinical setting.

METHODS

A total of 381 cases and 176 controls were enrolled between March 2001 and 2003 in a case-control study. Enrollees were over age 18 years from high socioeconomic countries visiting or living in Nepal. Stool samples were assessed by microbiologic, molecular identification, and enzyme immunoassay (EIA) methods, and antimicrobial susceptibility was determined by disk diffusion. Risk factors were assessed by questionnaires.

RESULTS

At least one enteropathogen was identified in 263 of 381 (69%) cases and 47 of 176 (27%) controls (p ≤ 0.001). Pathogens significantly detected among cases were Campylobacter (17%), enterotoxigenic Escherichia coli (ETEC) (15%), Shigella (13%), and Giardia (11%). Cyclospora was detected only in cases (8%) mainly during monsoon season. Although 71% of Campylobacter isolates were resistant to ciprofloxacin, 80% of bacterial isolates overall were sensitive to either ciprofloxacin or azithromycin while 20% were intermediately sensitive or resistant. No bacterial isolates were resistant to both drugs.

CONCLUSIONS

The most common pathogens causing TD in Nepal were Campylobacter, ETEC, and Shigella. Because resistance to fluoroquinolone or azithromycin was similar, one of these drugs could be used as empiric therapy for TD with the other reserved for treatment failures.

Cyclospora cayetanensis: a review, focusing on some of the remaining questions about cyclosporiasis

Cyclosporiasis is a protracted, relapsing gastroenteritis and has a short recorded history. Cyclospora cayetanensis is an enigmatic parasite since its discovery highlights the need for isolation of cases of infection that could be part of widespread outbreaks. 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 sometimes occur in the developed countries. In SubSaharan Africa and Egypt, cyclosporiasis has been reported to occur in both immunocompromised and immunocompetent patients. Zoonotic species of Cyclospora have also been identified worldwide in primates, indicating likely endemicity of this underreported disease. This can be attributed to the lack of awareness in the public and medical profession concerning the disease, which is, therefore, not routinely tested at the health centres. The correlation between the density of water contamination and the prevalence of cyclosporiasis among the individuals of each area is significant. No doubt, water is the main vehicle of transmission in the present community. Soil contact and poultry are significant risk factors. All literature on C. cayetanensis, cyclosporiasis worldwide, and endemic cyclosporiasis was searched from libraries, colleagues and internet. Although cyclosporiasis is considered an enigma worth unravelling, with many aspects of this disease and its transmission having been uncovered only recently, the situation has been rapidly changing since the disease first came to medical attention in the 1970s.

Cyclosporiasis outbreak, Indonesia

We describe an outbreak of Cyclospora cayetanensis infection among Dutch participants at a scientific meeting in September 2001 in Bogor, Indonesia. Fifty percent of the investigated participants were positive for C. cayetanensis. To our knowledge, this outbreak is the first caused by C. cayetanensis among susceptible persons in a disease-endemic area.

Foodborne protozoan parasites

This report addresses Cryptosporidium, Giardia, Cyclospora, and more briefly, Toxoplasma as the main parasitic protozoa of concern to food production worldwide. Other parasitic protozoa may be spread in food or water but are not considered as great a risk to food manufacture. The protozoan parasites Cryptosporidium, Giardia, and Cyclospora have proven potential to cause waterborne and foodborne disease. Toxoplasma gondii has been considered a risk in specific cases, but humans are not its primary host. Cryptosporidium and Giardia are widespread in the environment, particularly the aquatic environment, and major outbreaks of cryptosporidiosis and giardiasis have occurred as a result of contaminated drinking water. Large outbreaks of waterborne cyclosporiasis have not been identified. Cryptosporidium, Giardia, and Cyclospora have potential significance in the preparation and consumption of fresh produce and in catering practice, in which ready-to-eat foods may be served that have not received heat treatment. None of the three organisms Cryptosporidium, Giardia, and Cyclospora has been shown to be a problem for heat processed food or tap water that has undergone appropriate treatment at a water treatment works. All three are sensitive to standard pasteurisation techniques. Although humans are not a primary host for T. gondii, the potential exists for both waterborne and foodborne toxoplasmosis. Parasitic protozoa do not multiply in foods, but they may survive in or on moist foods for months in cool, damp environments. Their ecology makes control of these parasites difficult. For general control of parasitic protozoa in the food chain, the following steps are necessary: - Follow good hygienic practice in food service and catering industries.- Minimise dissemination of cysts and oocysts in the farming environment and via human waste management.- Include these microorganisms in Hazard Analysis Critical Control Point (HACCP) plans of water suppliers, industries or sectors that use fresh produce, and operations in which contaminated process or ingredient water could end up in the product (e.g., where water supplies may become contaminated).

Cyclospora cayetanensis and other intestinal parasites associated with diarrhea in a rural area of Jordan

Cryptosporidium spp. and Cyclospora cayetanensis have emerged as important causes of epidemic and endemic diarrhea in immunocompetent and immunocompromised hosts. The exact modes of transmission in certain rural areas are still unclear. Reports of water-borne and food-borne outbreaks suggest that fecally contaminated water or food acts as a vehicle of transmission. Two hundred stool samples of patients with gastroenteritis from four health centers in a rural area of Jordan were examined using formalin-ethyl acetate concentration, wet preparation, and modified acid-fast staining methods. Oocysts of C. cayetanensis and Cryptosporidium spp. were found in 6% and 8% of the samples respectively, mainly those of children. Parasites such as Entamoeba histolytica, Giardia lamblia, and other enteropathogens were also observed. The results reflect the seasonality of natural cyclosporiasis and cryptosporidiosis, being higher in the spring. The risk factors that were found by the Fisher test to be significant and might be associated with illness are the source of drinking water, contact with animals, and eating unwashed vegetables ( p<0.028, p<0.0005, p<0.00005 respectively).

Cyclospora cayetanesis

The novelty of C cayetanensis has led to some misconceptions about how best to detect its presence in stool examinations. Some reports have implied that the organism can only be seen on stained specimens, which is not true. The unstained organism can easily be identified by its characteristic size and internal structures. However, not doing a concentration procedure can reduce the chances of detecting C cayentanensis by up to 40%. Finally, there have been false positive reports of C cayetanensis when stained artifacts were mistaken for the real organism. The best way to become comfortable with the laboratory diagnosis of C cayentanensis is to obtain some known positive samples and practice identifying the oocysts using a variety of methods. The clinical syndrome associated with C cayentanensis is recognizable. The patient will usually have prominent anorexia, fatigue, nausea, and gas. Diarrhea, after the initial severe bout, is often intermittent, and submitted specimens may be formed despite a persistent feeling of being unwell.

Cyclospora spp

PURPOSE OF REVIEW

Infection with Cyclospora cayetanensis continues to pose many questions, both in endemic populations and in travelers and food-borne outbreaks. The present review discusses existing knowledge but focuses more on what is yet to be learned about this infection.

RECENT FINDINGS

Information on the parasite in endemic settings continues to be gathered, and similarities to and differences from other intestinal coccidia, especially Cryptosporidium spp., are becoming clearer. Food-borne outbreaks in North America continue despite efforts to identify and limit importation of particular items, such as berries, at certain times of the year. Study of Cyclospora spp. found in east African primates has shed some light on human infection but raises many new questions regarding the biology of the organism.

SUMMARY

Despite new information being gathered regarding Cyclospora spp., including infection rates in various age and population groups, significant gaps remain in our knowledge of such basic issues as the factors that influence infectivity, seasonality, mode of food contamination, and geographic distribution. These gaps highlight the need for continued study on a variety of fronts, including surveillance, and clinical and basic biology.

Emerging pathogen Cyclospora cayetanensis infection in Nepal

Cylospora cayetanensis, an emerging parasitic pathogen of human is being increasingly recognized throughout the world, however the means of transmission and the possibility of a reservoir host remain an enigma. A longitudinal study on cyclosporiasis in different parts of Nepal was carried out from April, 1995 until November, 2000. Fecal specimens were collected from symptomatic and asymptomatic patients. The data shows a distinct seasonality with the highest infection rates occurring during the summer and rainy season of the year. Attempts have been made to determine the sources of infection and possible reservoir hosts. Stools were examined from nearly 700 animals such as chickens, pigs, buffalos, cows, dogs, cats, monkeys, rats, mice and pigeons. In addition, vegetable farms around the Kathmandu Valley were examined during the seasonal high and low periods of transmission. C. cayetanensis-like oocysts were found in sewage water and from vegetable washings on five occasions during June, July, August, October, and November. Similarly, C. cayetanensis-like oocysts were recovered from mice, rats, chickens, and dogs. These results suggest that these sources may be important in the transmission of this parasitosis. However, further studies will be required to obtain definitive answers on transmission.

A risk assessment of emerging pathogens of concern in the land application of biosolids

Since the development of the United States Environmental Protection Agency's 503 biosolids Rule, which includes treatment requirements to reduce the threat of pathogen transmission, many new pathogens have been recognized which could be transmitted by biosolids. A risk analysis was performed assess which emerging pathogens would be most likely to survive treatments required for Class B biosolids before land application. The literature was reviewed on the resistance of emerging pathogens to temperature and other environmental factors to assess their probability of surviving various biosolids treatment processes. In addition existing information on occurrence in biosolids and dose response models for each pathogen was reviewed. It was concluded that adenoviruses and hepatitis A virus are the most thermally resistant viruses and can survive for prolonged periods in the environment. The protozoan parasites microsporidia and Cyclospora were unlikely to survive the temperatures achieved in anaerobic digestion and do not survive well under low moisture conditions. A risk model was used to assess the risk of infection and illness from enteric viruses after application of class B biosolids.

Microsporidia and Cyclospora: epidemiology and assessment of risk from the environment

Two classes of parasites with an environmental stage in their lifestyle have recently emerged as significant gastrointestinal pathogens for humans. Microsporidia represent a group that contains a number of genera related to the genus Cryptosporidium. They are generally transmitted via direct human to human contact, but can survive in water and food, and recently have been found in surface water used as drinking source water. Their most common host range is in patients with clinical AIDS. Limited work to date suggests the group is susceptible to chlorine achievable CxT (concentration x time) values and is coagulated by filtration. Cyclospora cayetanensis is a species of parasite that has caused outbreaks from contaminated food. Its major risk is from the use of inadequately treated water used for irrigation. Cyclospora can infect normal and immunosuppressed hosts. Current information regarding the lifestyle, transmission, and control of both groups of parasites are discussed, with a health risk assessment analysis.