Histologic proof of acalculous cholecystitis due to Cyclospora cayetanensis

Acalculous Cholecystitis in COVID-19 Patients: A Narrative Review

Acute acalculous cholecystitis (AAC) represents cholecystitis without gallstones, occurring in approximately 5-10% of all cases of acute cholecystitis in adults. Several risk factors have been recognized, while infectious diseases can be a cause of cholecystitis in otherwise healthy people. Coronavirus disease 2019 (COVID-19) is caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and has spread worldwide, leading to an unprecedented pandemic. The virus enters cells through the binding of the spike protein to angiotensin-converting enzyme 2 (ACE2) receptors expressed in many human tissues, including the epithelial cells of the gastrointestinal (GI) tract, and this explains the symptoms emanating from the digestive system. Acute cholecystitis has been reported in patients with COVID-19. The purpose of this review is to provide a detailed analysis of the current literature on the pathogenesis, diagnosis, management, and outcomes of AAC in patients with COVID-19.

Investigating the Potential Effects of COVID-19 Pandemic on Intestinal Coccidian Infections

New infectious agents pose a global threat to the healthcare system, and studies are conducted to estimate their health and epidemiological outcomes in the long run. The SARS-CoV-2 virus, which has caused the COVID-19 disease, was formerly assumed to be a respiratory virus; however, it can have serious systemic effects, affecting organs such as the gastrointestinal tract (GIT). Viral RNA was reported in the stool in a subset of patients, indicating another mode of transmission and diagnosis. In COVID-19, prolonged GIT symptoms, especially diarrhea, were associated with reduced diversity and richness of gut microbiota, immunological dysregulation, and delayed viral clearance. Intestinal coccidian parasites are intracellular protozoa that are most typically transmitted to humans by oocysts found in fecally contaminated food and water. Their epidemiological relevance is coupled to opportunistic infections, which cause high morbidity and mortality among immunocompromised individuals. Among immunocompetent people, intestinal coccidia is also involved in acute diarrhea, which is usually self-limiting. Evaluating the available evidence provided an opportunity to carefully consider that; the COVID-19 virus and coccidian protozoan parasites: namely, Cryptosporidium spp., Cyclospora cayetanensis, and Isospora belli, could mutually influence each other from the microbiological, clinical, diagnostic, and elimination aspects. We further systemically highlighted the possible shared pathogenesis mechanisms, transmission routes, clinical manifestations, parasite-driven immune regulation, and intestinal microbiota alteration. Finally, we showed how this might impact developing and developed countries prevention and vaccination strategies. To the best of our knowledge, there is no review that has discussed the reciprocal effect between coccidian parasites and COVID-19 coinfection.

Cyclosporiasis-Updates on Clinical Presentation, Pathology, Clinical Diagnosis, and Treatment

Cyclospora cayetanensis is an intestinal coccidian parasite transmitted to humans through the consumption of oocysts in fecally contaminated food and water. Infection is found worldwide and is highly endemic in tropical and subtropical regions with poor sanitation. Disease in developed countries is usually observed in travelers and in seasonal outbreaks associated with imported produce from endemic areas. Recently, summertime outbreaks in the United States have also been linked to locally grown produce. Cyclosporiasis causes a diarrheal illness which may be severe in infants, the elderly, and immunocompromised individuals. The increased adoption of highly sensitive molecular diagnostic tests, including commercially available multiplex panels for gastrointestinal pathogens, has facilitated the detection of infection and likely contributed to the increased reports of cases in developed countries. This manuscript reviews important aspects of the biology, epidemiology, and clinical manifestations of C. cayetanensis and provides an in-depth discussion of current laboratory diagnostic methods.

Acute acalculous cholecystitis due to infectious causes

Acute acalculous cholecystitis (AAC) is an inflammation of the gallbladder not associated with the presence of gallstones. It usually occurs in critically ill patients but it has also been implicated as a cause of cholecystitis in previously healthy individuals. In this subgroup of patients, infectious causes comprise the primary etiology. We, herein, discuss the pathophysiological mechanisms involved in AAC, focusing on the infectious causes. AAC associated with critical medical conditions is caused by bile stasis and gallbladder ischemia. Several mechanisms are reported to be involved in AAC in patients without underlying critical illness including direct invasion of the gallbladder epithelial cells, gallbladder vasculitis, obstruction of the biliary tree, and sequestration. We emphasize that multiple pathogenic mechanisms may concurrently contribute to the development of AAC in varying degrees. Awareness of the implicated pathogens is essential since it will allow a more focused examination of the histopathological specimens. In conclusion, additional research and a high degree of clinical suspicion are needed to clarify the complex spectrum of mechanisms that are involved in the pathogenesis of AAC.

Advances in Cyclosporiasis Diagnosis and Therapeutic Intervention

Cyclosporiasis is caused by the coccidian parasite Cyclospora cayetanensis and is associated with large and complex food-borne outbreaks worldwide. Associated symptoms include severe watery diarrhea, particularly in infants, and immune dysfunction. With the globalization of human food supply, the occurrence of cyclosporiasis has been increasing in both food growing and importing countries. As well as being a burden on the health of individual humans, cyclosporiasis is a global public health concern. Currently, no vaccine is available but early detection and treatment could result in a favorable clinical outcome. Clinical diagnosis is based on cardinal clinical symptoms and conventional laboratory methods, which usually involve microscopic examination of wet smears, staining tests, fluorescence microscopy, serological testing, or DNA testing for oocysts in the stool. Detection in the vehicle of infection, which can be fresh produce, water, or soil is helpful for case-linkage and source-tracking during cyclosporiasis outbreaks. Treatment with trimethoprim-sulfamethoxazole (TMP-SMX) can evidently cure C. cayetanensis infection. However, TMP-SMX is not suitable for patients having sulfonamide intolerance. In such case ciprofloxacin, although less effective than TMP-SMX, is a good option. Another drug of choice is nitazoxanide that can be used in the cases of sulfonamide intolerance and ciprofloxacin resistance. More epidemiological research investigating cyclosporiasis in humans should be conducted worldwide, to achieve a better understanding of its characteristics in this regard. It is also necessary to establish in vitro and/or in vivo protocols for cultivating C. cayetanensis, to facilitate the development of rapid, convenient, precise, and economical detection methods for diagnosis, as well as more effective tracing methods. This review focuses on the advances in clinical features, diagnosis, and therapeutic intervention of cyclosporiasis.

Cyclospora cayetanensis infection in humans: biological characteristics, clinical features, epidemiology, detection method and treatment

Cyclospora cayetanensis, a coccidian parasite that causes protracted and relapsing gastroenteritis, has a short recorded history. At least 54 countries have documented C. cayetanensis infections and 13 of them have recorded cyclosporiasis outbreaks. Cyclospora cayetanensis infections are commonly reported in developing countries with low-socioeconomic levels or in endemic areas, although large outbreaks have also been documented in developed countries. The overall C. cayetanensis prevalence in humans worldwide is 3.55%. Among susceptible populations, the highest prevalence has been documented in immunocompetent individuals with diarrhea. Infections are markedly seasonal, occurring in the rainy season or summer. Cyclospora cayetanensis or Cyclospora-like organisms have also been detected in food, water, soil and some other animals. Detection methods based on oocyst morphology, staining and molecular testing have been developed. Treatment with trimethoprim-sulfamethoxazole (TMP-SMX) effectively cures C. cayetanensis infection, whereas ciprofloxacin is less effective than TMP-SMX, but is suitable for patients who cannot tolerate co-trimoxazole. Here, we review the biological characteristics, clinical features, epidemiology, detection methods and treatment of C. cayetanensis in humans, and assess some risk factors for infection with this pathogen.

Silver nanoparticles as a therapeutic agent in experimental cyclosporiasis

Cyclosporiasis is an emerging worldwide infection caused by an obligate intracellular protozoan parasite, Cyclospora cayetanensis. In immunocompetent patients, it is mainly manifested by self-limited diarrhea, which is persistent and may be fatal in immunocompromised patients. The standard treatment for cyclosporiasis is a combination of two antibiotics, trimethoprim and sulfamethoxazole. Gastrointestinal, haematologic and renal side effects were reported with this combination. Moreover, sulfa allergy, foetal anomalies and recurrence were recorded with no alternative drug treatment option. In this study, silver nanoparticles were chemically synthesized to be evaluated for the first time for their anti-cyclospora effects in both immunocompetent and immunosuppressed experimental mice in comparison to the standard treatment. The effect of silver nanoparticles was assessed through studying stool oocyst load, oocyst viability, ultrastructural changes in oocysts, and estimation of serum gamma interferon. Toxic effect of the therapeutic agents was evaluated by measuring liver enzymes, urea and creatinine in mouse sera. Results showed that silver nanoparticles had promising anti-cyclospora potentials. The animals that received these nanoparticles showed a statistically significant decrease in the oocyst burden and number of viable oocysts in stool and a statistically significant increase in serum gamma interferon in comparison to the corresponding group receiving the standard treatment and to the infected non-treated control group. Scanning electron microscopic examination revealed mutilated oocysts with irregularities, poring and perforations. Biochemical results showed no evidence of toxicity of silver nanoparticles, as the sera of the mice showed a statistically non-significant decrease in liver enzymes in immunocompetent subgroups, and a statistically significant decrease in immunosuppressed subgroups. Furthermore, a statistically non-significant decrease in urea and creatinine was recorded in all subgroups. Thus, silver nanoparticles proved their effectiveness against Cyclospora infection, and this will draw the attention to its use as an alternative to the standard therapy.

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.

Human cyclosporiasis

Cyclospora species are socioeconomically important protistan pathogens. Cyclospora cayetanensis is usually transmitted via food or water to a human host via the faecal-oral route and can cause the gastrointestinal disease cyclosporiasis, which can be complicated by extra-intestinal disorders, particularly in immune-compromised people. Although more than 2 million children die each year from diarrhoeal diseases worldwide, it is not known to what extent cyclosporiasis is involved. Few epidemiological data are available on Cyclospora as a water-borne and food-borne pathogen in both underprivileged communities and developed countries. To gain an improved understanding of human cyclosporiasis, this Review describes the background of Cyclospora, summarises salient aspects of the pathogenesis, epidemiology, diagnosis, treatment, and control of cyclosporiasis, and explores what is known about its prevalence and geographical distribution. The findings show that the effect on human health of cyclosporiasis is likely underestimated, and recommendations are made about areas of future research and the prevention and control of this disease within an international collaborative context.

Parasites

Parasites are an important cause of human disease worldwide. The clinical severity and outcome of parasitic disease is often dependent on the immune status of the host. Specific parasitic diseases discussed in this chapter are amebiasis, giardiasis, cryptosporidiosis, cyclosporiasis, cystoisosporiasis, microsporidosis, granulomatous amebic encephalitis, toxoplasmosis, leishmaniasis, Chagas disease, malaria, babesiosis, strongyloidiasis, and scabies.

First detection of acalculous cholecystitis associated with Sarcocystis infection in a patient with AIDS

Acalculous cholecystitis and cholangitis are increasingly being recognized as complications of AIDS. The opportunistic parasites that have been most commonly associated with these disorders are Cryptosporidium species, Isospora belli, Cyclospora cayetanensis and Enterocytozoon bieneusi. The authors performed a parasitological survey on the gallbladder tissue sections of patients underwent cholecystectomy due to chronic acalculous cholecystitis at the Shiraz University of Medical Sciences, Iran. Light microscopic investigation in more than three hundred archived histopathological slides revealed the presence of sexual stages (i.e., mature sporocysts) of a coccidial protozoan in a patient with AIDS who developed acalculous cholecystitis as confirmed by histological, parasitological and molecular tests in which Sarcocystis species was the only identifiable pathogen in gallbladder sections. In the best of our knowledge it's the first documented case of chronic non-calculous cholecystitis due to Sarcocystis parasite in an Iranian AIDS patient from worldwide.

Parasitic infections in solid organ transplant recipients

Parasitic infections are an uncommon but potentially severe complication in solid organ transplant (SOT) recipients. An increase in donors who have emigrated from tropical areas and more transplant recipients traveling to endemic areas have led to a rise in parasitic infections reported among SOT recipients. Clinicians should include these infections in their differential diagnosis and promote adherence to preventive measures in SOT recipients.

Acute acalculous cholecystitis

Acute acalculous cholecystitis (ACC) can develop with or without gallstones after surgery and in critically ill or injured patients. Diabetes mellitus, malignant disease, abdominal vasculitis, congestive heart failure, cholesterol embolization, shock, and cardiac arrest also have been associated with AAC. The pathogenesis of AAC is complex and multifactorial. Ultrasound of the gallbladder is most accurate for the diagnosis of AAC in the critically ill patient. CT is probably of comparable accuracy, but carries both advantages and disadvantages. Rapid improvement may be expected when AAC is diagnosed correctly and cholecystostomy is performed timely.

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.

Clinical significance of enteric protozoa in the immunosuppressed human population

Globally, the number of immunosuppressed people increases each year, with the human immunodeficiency virus (HIV) pandemic continuing to spread unabated in many parts of the world. Immunosuppression may also occur in malnourished persons, patients undergoing chemotherapy for malignancy, and those receiving immunosuppressive therapy. Components of the immune system can be functionally or genetically abnormal as a result of acquired (e.g., caused by HIV infection, lymphoma, or high-dose steroids or other immunosuppressive medications) or congenital illnesses, with more than 120 congenital immunodeficiencies described to date that either affect humoral immunity or compromise T-cell function. All individuals affected by immunosuppression are at risk of infection by opportunistic parasites (such as the microsporidia) as well as those more commonly associated with gastrointestinal disease (such as Giardia). The outcome of infection by enteric protozoan parasites is dependent on absolute CD4(+) cell counts, with lower counts being associated with more severe disease, more atypical disease, and a greater risk of disseminated disease. This review summarizes our current state of knowledge on the significance of enteric parasitic protozoa as a cause of disease in immunosuppressed persons and also provides guidance on recent advances in diagnosis and therapy for the control of these important parasites.

Cyclosporiasis: an update

Cyclosporiasis is a food- and water-borne infection that affects healthy and immunocompromised individuals. Awareness of the disease has increased, and outbreaks continue to be reported among vulnerable hosts and now among local residents in endemic areas. Advances in molecular techniques have improved identification of infection, but detecting food and water contamination remains difficult. Further understanding of the biology, pathogenesis, and control of infection and transmission has been hindered by the difficulty of propagating the organism, lack of reliable oocyst viability and infectivity assays, and inability to experimentally infect animals and human volunteers. This article provides a general review and presents recent insights into the organism and disease.

[Immigration and HIV Infection. An approximation to parasitic and viral infections]

Highly-active antiretroviral therapy is effective in reducing opportunistic infections in industrialized countries. However, opportunistic parasitic infections remain the leading cause of HIV-related mortality in developing countries. These infections can also affect HIV-positive immigrants residing in Spain, as well as HIV-infected patients traveling to low-income countries. In addition, immigrants often have viral infections caused by herpesvirus, papillomavirus and polyomavirus, which are closely related to risk behaviors and commercial sex. The present article reviews the characteristics of parasitic and viral infections in patients with HIV infection with the aim of improving understanding of this vulnerable population group.

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.

Treatment of parasitic diarrhea in HIV-infected patients

Parasitic infections responsible for diarrhea have a worldwide distribution, overlapping with AIDS in most countries. Indeed, highly active antiretroviral therapy has markedly reduced the incidence of most parasitic opportunistic infections, but parasite-related diarrhea remains frequent and probably underestimated in developing countries. In this review, we focus on the advances in molecular epidemiology, diagnosis and current treatment of the most prevalent parasitic infections in HIV-infected patients. Most of these parasites are protozoa, whose diagnosis at the laboratory requires some adapted technique and expertise. We highlight the importance of diagnosis and the skill of the laboratory of parasitology, since most parasitic infections responsible for diarrhea in AIDS patients can be treated.

Cyclosporiasis: a point source outbreak acquired in Guatemala

BACKGROUND

Cyclosporiasis is a disease due to Cyclospora cayetanensis, an emerging coccidian parasite first described in 1979. It is an orally transmitted disease that is more frequent in tropical and subtropical areas. Cyclospora cayetanensis has been mainly described as a cause of travelers' diarrhea. This pathogen has given rise to a number of epidemic outbreaks attributable to ingestion of imported foods, particularly from tropical areas.

METHODS

Descriptive study of clinical and epidemiological data of a small epidemic outbreak of C cayetanensis-induced gastroenteritis.

RESULTS

Seven confirmed cases of C cayetanensis among Spanish nationals who had traveled to Antigua Guatemala are described. The incubation period was 6 days. Diarrhea, asthenia, anorexia, borborygmi, flatulence, and abdominal distension were present in all cases. Fever and heart burn in 85.7%. Weight loss in 71.4%. Abdominal pain, rectal tenesmus, and nausea in 42.8%. Vomiting and eructation in 14.2%. Heart burn was a frequent symptom, a finding not often previously described. The infection was probably acquired from raspberry juice. All cases improved with trimethoprim/sulphametoxazol.

CONCLUSIONS

Cyclosporiasis is a cause of travelers' diarrhea. Parasitology laboratories must be advised of clinical suspicion of cyclosporiasis so that they can conduct a suitable targeted study; otherwise, false negative results may arise.

Cardiac arrest associated with febrile illness due to U.K. acquired Cyclospora cayetanensis

This report describes a 43 yr old man diagnosed with U.K. acquired cyclospora cayetanensis infection resulting in fever and diarrhoea. In course of the febrile illness, he suffered an out of hospital cardiac arrest. Extensive cardiac investigation including a transthoracic echocardiogram, coronary angiogram, and cardiac electrophysiological studies failed to identify the cause. The possible links between cyclospora infection and cardiac arrest are explored. Fever has been reported as a precipitant for idiopathic ventricular fibrillation in patients with the Brugada syndrome but also rarely in individuals with normal hearts. Clinicians should be aware of a possible link between any febrile illness and potentially fatal ventricular dysrhythmia.

Acalculous cholecystitis in a patient with Plasmodium falciparum infection: a case report and literature review

Acute acalculous cholecystitis (AAC) can occur without gallstones in critically ill or injured patients and has also been associated with various infectious agents.(1-4) We report here a case of AAC in a patient with Plasmodium falciparum malaria.

Acute Acalculous Cholecystitis

Acute acalculous cholecystitis is defined as acute inflammation of the gallbladder in the absence of gallstones. Patients are usually critically ill with atherosclerotic heart disease, recent trauma, burn injury, surgery, or hemodynamic instability. The presentation of acute acalculous cholecystitis may be insidious, characterized by unexplained fever, leukocytosis, hyperamylasemia, or abnormal aminotransferases, and patients often lack right upper quadrant tenderness. Diagnostic evaluation includes ultrasonography, computerized tomography, and cholescintigraphy. Given the high mortality of untreated disease, definitive treatment consists of cholecystectomy or, in poor surgical candidates, cholecystostomy. Endoscopic therapy with nasobiliary drainage and lavage is an effective treatment option in patients unable to tolerate surgery or cholecystostomy.

Cholestasis in HIV-infected patients

Cholestasis is frequently observed in the HIV-infected population and can be caused by drugs, such as highly active antiretroviral therapy (HAART) and antimicrobial agents, and by opportunistic infections of the liver. Less common causes such as HIV-related malignancies or biliary tract disease are also encountered. Most disorders respond to medical management, but patient outcome was often dictated by the stage of the HIV infection and concomitant illnesses in the pre-HAART era. Prompt recognition and specific treatment may improve the outcome for these patients in the HAART era.

Acute acalculous cholecystitis

Acute cholecystitis can develop without gallstones in critically ill or injured patients. However, the development of acute acalculous cholecystitis is not limited to surgical or injured patients, or even to the intensive care unit. Diabetes, malignant disease, abdominal vasculitis, congestive heart failure, cholesterol embolization, and shock or cardiac arrest have been associated with acute acalculous cholecystitis. Children may also be affected, especially after a viral illness. The pathogenesis of acute acalculous cholecystitis is a paradigm of complexity. Ischemia and reperfusion injury, or the effects of eicosanoid proinflammatory mediators, appear to be the central mechanisms, but bile stasis, opioid therapy, positive-pressure ventilation, and total parenteral nutrition have all been implicated. Ultrasound of the gallbladder is the most accurate diagnostic modality in the critically ill patient, with gallbladder wall thickness of 3.5 mm or greater and pericholecystic fluid being the two most reliable criteria. The historical treatment of choice for acute acalculous cholecystitis has been cholecystectomy, but percutaneous cholecystostomy is now the mainstay of therapy, controlling the disease in about 85% of patients. Rapid improvement can be expected when the procedure is performed properly. The mortality rates (historically about 30%) for percutaneous and open cholecystostomy appear to be similar, reflecting the severity of illness, but improved resuscitation and critical care may portend a decreased risk of death. Interval cholecystectomy is usually not indicated after acute acalculous cholecystitis in survivors; if the absence of gallstones is confirmed and the precipitating disorder has been controlled, the cholecystostomy tube can be pulled out after the patient has recovered.

Cyclospora cayetanensis: a review of an emerging parasitic coccidian

Cyclospora cayetanensis is a sporulating parasitic protozoan that infects the upper small intestinal tract. It has been identified as both a food and waterborne pathogen endemic in many developing countries. It is an important agent of Traveller's Diarrohea in developed countries and was responsible for numerous foodborne outbreaks in the United States and Canada in the late 1990s. Like Cryptosporidium, infection has been associated with a variety of sequelae such as Guillain-Barré syndrome, reactive arthritis syndrome (formally Reiter syndrome) and acalculous cholecystitis. There has been much debate as to where to place C. cayetanensis taxonomically due to its homology with Eimeria species. To date, the only genomic DNA sequences available are the ribosomal DNA of C. cayetanensis and three other species; within these a high degree of homology has been observed. This homology and the lack of sequence data from other Cyclospora species have hindered identification methods.

Parasitic infections of the gastrointestinal tract

Intestinal parasites continue to be a significant health problem in both developed and developing countries. In developed countries, protozoans are more commonly the cause of gastrointestinal infections than are helminths. Some protozoan parasites have stages in which, in addition to being resistant to chemicals used for water treatment, they are small enough to pass through commonly used filtration processes. The relatively large size of helminth eggs increases the likelihood of their removal during water filtration. The direct impact of protozoan parasites on both human and animal health is considerable, and there is some evidence that infection may contribute to the development of various forms of intestinal dysregulation as well as disseminated infection, especially in AIDS patients. Protozoans of special interest, due to either their frequency of isolation or their role as emerging pathogens, include Giardia duodenalis, Cryptosporidium parvum, Cyclospora cayetanensis, and the microsporidians, Enterocytozoon bieneusi and Encephalitozoon intestinalis.

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 CD₃⁺, CD₄⁺, CD₈⁺ and the ratio of CD₄⁺/CD₈⁺ 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.

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.