Endogenous Developmental Cycle of the Human Coccidian Cyclospora cayetanensis.

Cyclospora cayetanensis is a coccidian parasite of humans of known and growing importance. However, we are surprisingly naïve as to our understanding of how to diagnose it and how it develops inside the human body. Here we provide details of the developmental stages of C. cayetanensis in the gallbladder of a 33-yr-old male with human immunodeficiency virus. The gallbladder was removed surgically in 2001 because of severe abdominal pain. For the present study, the archived paraffin block of gallbladder was processed for light microscopy and transmission electron microscopy (TEM). Histological sections were examined after staining with hematoxylin and eosin (HE) or using the periodic acid Schiff (PAS) reaction. Immature and mature asexual stages, gamonts, and oocysts were seen in epithelial cells, both in the superficial epithelium and in glands. The merozoites were present singly, in pairs, and 3 or more in a single parasitophorous vacuole in the host cytoplasm. Up to 6 nuclei were seen in immature schizonts without evidence of merozoite formation. Mature schizonts were 7.6 × 5.1 µm and contained up to 10, 3-4 µm long merozoites. Merozoites were 0.6 to 2.0 µm wide, and their shape varied from pear-shaped to slender. Merozoites were generally PAS-positive; however, some were intensely positive, some had only minute granules, while others were PAS-negative. The microgamonts (male) were 6.6 × 5.2 µm and contained fewer than 20 microgametes around a residual body. The microgametes were up to 2 µm long and were flagellated. Macrogamonts (female) contained distinctive eosinophilic wall-forming bodies that varied in size and were less than 1 µm in HE-stained sections. Macrogamonts were 5.8-6.5 × 5.3-6.5 µm. Oocysts in sections were unsporulated and had a diameter of 5.7-7.5 µm. The TEM examination confirmed the histologic findings. The DNA extracted from paraffin sections was confirmed as C. cayetanensis with real-time PCR. The detailed description of the life cycle stages of C. cayetanensis reported here in an immunosuppressed patient could facilitate histopathologic diagnosis of this parasite. We have shown that the parasite's development more closely resembles that of Cystoisospora than Eimeria and that the parasite has multiple nuclei per immature meront indicating schizogony, and we have undermined evidence for a Type II meront.

Cyclospora infection in a young woman with human immunodeficiency virus in Hong Kong: a case report.

BACKGROUND: Cyclospora is an uncommon pathogen. The diagnosis of Cyclospora infection can be difficult because of its scarcity in developed countries, intracellular mode of life, small size of the parasite and its inability to take up routine microscopic stains. However, it is endemic in many countries in Asia, Africa, Central and South America. With the increase in travels to these areas, the number of cases is expected to increase. Moreover, it is found to be associated with numerous food-borne outbreaks. CASE PRESENTATION: We encountered a patient with human immunodeficiency virus presented with 6 months of diarrhoea. The initial investigation was unrevealing. The diagnosis of Cyclospora infection was finally made on the histological sample obtained by colonoscopy. Moreover, the initial therapy with ciprofloxacin was not effective, while trimethoprim/sulfamethoxazole resulted in final cure of the disease. CONCLUSION: Travel and food histories are important for the suspicion of Cyclospora infection. Histological examination is more sensitive in making a diagnosis of Cyclospora infection of the gut than fecal microscopic examination. Trimethoprim/sulfamethoxazole is a more reliable therapy for Cyclospora infection in patients with human immunodeficiency virus.

Correlation between CD4 counts of HIV patients and enteric protozoan in different seasons - an experience of a tertiary care hospital in Varanasi (India).

BACKGROUND: Protozoan infections are the most serious among all the superimposed infections in HIV patients and claim a number of lives every year. The line of treatment being different for diverse parasites necessitates a definitive diagnosis of the etiological agents to avoid empirical treatment. Thus, the present study has been aimed to elucidate the associations between diarrhoea and CD4 counts and to study the effect of HAART along with management of diarrhoea in HIV positive patients. This study is the first of its kind in this area where an attempt was made to correlate seasonal variation and intestinal protozoan infestations. METHODS: The study period was from January 2006 to October 2007 wherein stool samples were collected from 366 HIV positive patients with diarrhea attending the ART centre, inpatient department and ICTC of S.S. hospital, I.M.S., B.H.U., Varanasi. Simultaneously, CD4 counts were recorded to assess the status of HIV infection vis-à-vis parasitic infection. The identification of pathogens was done on the basis of direct microscopy and different staining techniques. RESULTS: Of the 366 patients, 112 had acute and 254 had chronic diarrhea. The percentages of intestinal protozoa detected were 78.5% in acute and 50.7% in chronic cases respectively. Immune restoration was observed in 36.6% patients after treatment on the basis of clinical observation and CD4 counts. In 39.8% of HIV positive cases Cryptosporidium spp. was detected followed by Microsporidia spp. (26.7%). The highest incidence of intestinal infection was in the rainy season. However, infection with Cyclospora spp. was at its peak in the summer. Patients with chronic diarrhea had lower CD4 cell counts. The maximum parasitic isolation was in the patients whose CD4 cell counts were below 200 cells/microl. CONCLUSION: There was an inverse relation between the CD4 counts and duration of diarrhea. Cryptosporidium spp. was isolated maximum among all the parasites in the HIV patients. The highest incidence of infection was seen in the rainy season.

[Study on the expression of immune function in cases infected by Cyclospora cayetanensis].

In Cyclospora cayetanensis oocyst-positive patients, T cell subsets in peripheral mononuclear cell and membrane interleukin-2 receptor (mIL-2R) were detected with the method of biotin-streptavidin (BSA) and soluble interleukin-2 receptor (sIL-2R) as well as special IgG, IgM in serum was detected by ELISA. Results showed that there is a significant difference between the infected and uninfected individuals.

Cyclospora infection in five immunocompetent patients in a Turkish university hospital.

Infection with Cyclospora has been increasingly reported worldwide in both immunocompetent and immunocompromised individuals. Here the cases of five patients infected with Cyclospora cayetanensis, who sought medical care at Hacettepe University in Turkey, are reported. Diarrhoea occurred from five to fifteen times a day in all of these patients, whose ages ranged from 27 to 67 years. All the patients were considered immunocompetent. Identification of C. cayetanensis was made by detection of the oocysts by using a modified acid-fast stain.

Cyclosporiasis associated with diarrhoea in an immunocompetent patient in Turkey.

Cyclospora cayetanensis, the parasitic agent responsible for human cyclosporiasis, is an emerging worldwide cause of diarrhoea in immunocompetent people as well as in immunocompromised patients, such as those with AIDS. Reported here is the case of a 30-year-old Turkish woman, a lawyer, who was admitted to hospital in July 2002 with complaints of watery diarrhoea, anorexia, nausea, vomiting, abdominal pain and weight loss over a period of 1 week. Cyclospora sp. oocysts were determined by using modified Kinyoun's acid-fast stain. The patient was treated with trimethoprim/sulfamethoxazole (160/800 mg) b.i.d. for 7 days. This report is the first example of autochthonous cyclosporiasis in an immunocompetent patient in Turkey.

Cyclospore cayetanensis in Anhui, China.

AIM: To investigate the infection of Cyclospore cayetanensis in Anhui Province. METHODS: Identification of Cyclospore cayetanensis was made microscopically by finding the oocysts of Cyclospore cayetanensis in fecal smears taken from the infants, pupils and adults with obstinate diarrhea, and immunocompromised individuals by using a auramine-phenol stain and modified acid-fast stain. Cellular immune function was detected with biotin-streptavidin (BSA), and the specific antibody against Cyclospore cayetanensis was detected with method of ELISA. RESULTS: (1) The positive rates of Cyclospore cayetanensis infection in infants, pupils, infants and adults with obstinate diarrhea and with immunocompromised individuals were significantly different (P<0.01), with the rates of 0 %, 0.50 % (1/200), 5.62 % (10/178), and 9.38 % (3/32) respectively. (2) The infection rates of males and females were 2.61 % (10/383) and 1.44 % (4/227) respectively, with no significant difference (P<0.05). (3) The positive rates of population with oocysts in urban and rural areas were 0.92 % (3/325) and 3.86 % (11/285) respectively. (4) The positive rates of CD(3)(+), CD(4)(+), CD(8)(+) and the ratio of CD(4)(+)/CD(8)(+) of individuals with and without oocysts were significantly different (P<0.05, P<0.01), and their values were (64.28+/-6.55) %, (43.55+/-5.80) %, (28.23+/-4.32) %, 1.52+/-0.32 and (58.97+/-5.23) %, (39.26+/-4.93) %, (30.54+/-5.17) %,1.26+/-0.21, respectively. (5) Specific IgG, IgM and IgG+IgM in serum of the patients with oocyst were significantly different (P<0.01) with the positive rates of 63.41 % (9/14), 17.07 % (1/14) and 19.51 % (4/14) respectively. CONCLUSION: Cyclospore cayetanensis infection is present in Anhui, China and it was confirmed to be a new pathogen associated with children diarrhea, adults obstinate diarrhea and diarrhea in immunocompromised individuals. Among all the infected individuals, adult obstinate diarrhea patients and immunocompromised individuals are common. Feces examination of oocysts and serological examination of the specific antibody will be of much help in the diagnosis of Cyclospore cayetanensis infection.

Parasitic diseases and immunodeficiencies.

In the last two decades, major immunodeficiency syndromes have strongly influenced medical parasitology. Some animal parasitoses, once unknown in human medicine, have become zoonotic and sometimes anthroponotic. In other cases, the clinical evolution of human parasitoses has been severely aggravated and/or modified in immunodeficient patients especially in toxoplasmosis, cryptosporidiosis, leishmaniasis, strongyloidiasis and scabies. The parasites implicated are varied (protozoa, helminths and even Acaridae) but have in common the capacity to reproduce in or on the human host. These immunodeficiency syndromes are often related to AIDS but other major immunodepressions, such as post-therapeutically in organ transplantation, may also be responsible and raise difficult problems for prevention. The munological mechanisms involved are not always well understood. In addition, genetic predisposition factors, gradually becoming better-understood in parasites and man, complete and complicate our understanding of the immunological mechanisms.

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.