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Case Report |
Department of Clinical Microbiology and Microbiology, Hacettepe University Medical School, Ankara, 06100, Turkey
Correspondence
Banu Sancak
banusancak{at}yahoo.com
Received 4 August 2005
Accepted 3 November 2005
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Introduction |
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People infected with C. cayetanensis excrete oocysts that are not infectious. Oocysts become sporulated in one to several weeks and infect individuals who ingest them. As the parasite requires 1–2 weeks to sporulate, it is unlikely that it can pass directly from one person to another. The infection dose is presumed to be low (Jackson et al., 1997). Outbreaks have been linked to contaminated water and various types of fresh produce.
Females and males are equally susceptible to Cyclospora infection. C. cayetanensis can cause illness that varies significantly with age and condition of the host. Infection occurs in people of all ages and in both immunocompetent and immunocompromised hosts (O'Mahony & Mannion, 1998; Ooi et al., 1995). In AIDS patients the infection causes a more severe and chronic illness. Most AIDS patients develop prolonged, severe life-threating diarrhoea.
In recent years, several studies have shown that C. cayetanensis is distributed worldwide (Sterling & Ortega, 1999; Brown & Rotschafer, 1999), and its prevalence is considerably higher in developing countries than in Europe and North America. It has caused a number of sporadic cases and epidemic outbreaks of diarrhoeal illness. The majority of the isolates from humans have been from residents of developing countries or from travellers returning from Haiti, Mexico, Guatemala, Puerto Rico, Morocco, Pakistan and India (Clarke & McIntyre, 1996; Pollok et al., 1992).
Since 1995, many foodborne outbreaks of cyclosporiasis have been documented in the USA and Canada (Huang et al., 1995; Koumans et al., 1998; Herwaldt & Ackers, 1997; Centers for Disease Control and Prevention, 1998). These outbreaks were mostly attributed to imported raspberries from Guatemala and other imported fruits and vegetables where contaminated water had been used (Herwaldt & Ackers, 1997; Centers for Disease Control and Prevention, 1996; Osterholm, 1997).
Here we report five cases of cyclosporiasis in immunocompetent patients who were not related and had no common activities.
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Case reports |
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Case 2
In August 2004, a 28-year-old woman presented with watery diarrhoea for 3 days, 15 times a day, weight loss and anorexia. Physical examination was normal. She had travelled to the south coast of Turkey a week before her complaints.
Case 3
In August 2004, a 44-year-old man presented with diarrhoea accompanied by anorexia, weight loss and abdominal cramps. Two weeks before his complaint, he had travelled to Pakistan for a week and to the south coast of Turkey for a couple of days.
Case 4
In August 2004, a 27-year-old woman visited the department of gastroenterology, complaining of a 5-day history of watery diarrhoea and malaise. She had no fever or abdominal cramp. Physical examination was found to be normal. She had no history of recent travel.
Case 5
In August 2004, a 31-year-old man presented with watery diarrhoea (five to six times a day) for 2 weeks. He complained of weight loss, cramping abdominal pain and malaise. He had no history of recent travel.
In all of the five cases, routine stool cultures for bacteria were negative. No leukocytes were seen on microscopic examination of the fecal samples. Although three stool samples collected 3 days consecutively examined for ova were found as negative, a modified acid-fast staining revealed pink to reddish stained oval to round organisms 8–10 µm in diameter, suggestive of Cyclospora spp. oocysts (Fig. 1
). For modified acid-fast staining, 2 % sulfuric acid was used for decolorization. In none of the patients was immunodeficiency determined. All the patients were treated with trimethoprim (160 mg)/sulfamethoxazole (800 mg) b.i.d. for 7 days. After treatment, clinical symptoms of cyclosporiasis disappeared between 7 and 15 days.
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Discussion |
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TOPIntroductionCase reportsDiscussionREFERENCES |
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The prevalence of Cyclospora infection appears to vary depending on the population studied. The highest incidence has been described in underdeveloped countries, but infection is most common in tropical and subtropical areas. In the study of Wang et al. (2002) in Anhui, China, the infection rate was found to be 0·25 % in the normal population, 5·62 % in patients with diarrhoea and 9·32 % in immunocompromised patients. In a study by Chacin-Bonilla et al. (2003) in Venezuela, infection with Cyclospora was identified in 6·1 % of the subjects, and of the 13 subjects shedding oocysts, 11 (84·6 %) were asymptomatic. The incidence of the organism is very low in Europe and North America. In a laboratory-based study in the USA, Cyclospora was found in 0·2 % of stool specimens (Wurtz et al., 1993). With the exception of some outbreaks, the overall prevalence of Cyclospora in North America appears to be far less than 1 %. It was also found in 0·1 % of 1333 stool specimens from healthy individuals in the UK (Soave, 1996). Most cases of Cyclospora infection reported from Europe have been sporadic, and almost all of them were detected in persons after travel to endemic areas (Pollok et al., 1992; Gascon et al., 1995; Petry et al., 1997). Alakpa et al. (2002) collected 1109 stool samples between 1999 and 2000 from Nigeria, and only found 11 positive (0·99 %) samples of C. cayetanensis oocysts.
Anyone can become infected with Cyclospora but the prevalence in children tends to be much higher. Cyclospora is commonly associated with paediatric gastroenteritis in Guatemala, Peru, Nepal and other developing countries (Hoge et al., 1995; Ortega et al., 1993; Madico et al., 1997). In the study of Lopez et al. (2003), the prevalence of Cyclospora infection was higher in children 
10 years of age than in older people. Studies from Guatemala and Peru have similar results (Madico et al., 1997; Bern et al., 1999; Bern et al., 2000). Ortega et al. (1993) found the parasite in 6–18 % of Peruvian children. In the study of Hoge et al. (1995), the prevalence of Cyclospora species among children at least 18 months of age was found to be 12 % in Nepal. Among asymptomatic children, the prevalence was 2 %.
Cyclospora causes prolonged and watery diarrhoea in both immunocompetent patients and immunocompromised (O'Mahony & Mannion, 1998; Ooi et al., 1995; Wurtz et al., 1993) patients such as those with AIDS. Here we report the cases of five immunocompetent patients who had watery diarrhoea associated with Cyclospora. Only six cases of C. cayetanensis infection have been reported recently in Turkey (Yazar et al., 2004). Of these six cases, only two were in immunocompetent patients.
That all the patients were living in Ankara, the capital city of Turkey, and were diagnosed in August 2004 suggested that the organism could be waterborne or foodborne. However, all the patients used bottled water for drinking and none of them consumed the same food. Two of the patients travelled to the same town on the south coast before developing watery diarrhoea. It is possible that these two could have been infected by the same source. However, it should be kept in mind that one of these patients could have acquired C. cayetanensis from his travel to Pakistan also. Therefore, as a result we could not find any source according to the histories of the patients.
Generally throughout the world, especially in developing countries, there are some difficulties in the identification of this parasite in stools. In most of the laboratories, stool specimens examined for ova and parasites are not usually examined for Cyclospora unless such testing is requested. The identification of this parasite requires special laboratory tests that are not routinely done. The stain mostly used to identify the oocysts of Cyclospora and Cryptosporidium is a modified acid-fast stain (Yazar et al., 2004; Baxby et al., 1984; Eberhard et al., 1997). The oocysts show variability in staining with this modified acid-fast stain, ranging from no staining to staining pink or deep purple. This variability may result in the misidentification of the parasite. Also, Cyclospora oocysts can be secreted intermittently and shed in relatively low numbers. Therefore, one negative stool specimen does not rule out infection with Cyclospora. At least three stool samples should be tested before a negative result is reported.
Cyclospora and Cryptosporidium are obligate, intracellular coccidian protozoan parasites that infect the gastrointestinal tract of humans, causing severe diarrhoea. Both of them produce oocysts, which are excreted in the faeces. Since the oocysts of Cyclospora are stained acid-fast like those of Cryptosporidium, there is close similarity between these two parasites. Therefore, more attention should be given to differentiation between the two. The C. cayetanensis oocyst diameter (8–10 µm) is larger than that of Cryptosporidium (about 5 µm).
Patients infected with Cyclospora have non-specific symptoms such as watery diarrhoea, abdominal distention, abdominal pain and anorexia, which can easily be confused with those of other intestinal diseases. Therefore, if the patient has prolonged diarrhoea, a history of travel or is immunocompromised or if there is a waterborne/foodborne-related diarrhoea outbreak, one should always remember that it can be caused by C. cayetanensis. If several stool samples are found to be negative for routine bacteriological, virological and parasitological tests and the patient still has gastrointestinal symptoms, examination for C. cayetanensis with modified acid-fast staining must be done.
Cyclospora has been isolated in chronic diarrhoea of immunocompetent patients, therefore this infection must be taken into consideration, especially in patients with prolonged diarrhoea. More coccidial infections could be detected if modified acid-fast staining is routinely performed.
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ACKNOWLEDGEMENTS |
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