RARE DISEASE
Cyclosporiasis
Cyclosporiasis
Cyclosporiasis
Drug discovery
0
drugs
With orphan designations
Overview
Cyclosporiasis is an intestinal infection caused by the protozoan Cyclospora cayetanensis, transmitted via fecal-oral contamination of food/water. Clinical features include watery diarrhea, abdominal cramps, fatigue, weight loss, and relapsing symptoms lasting weeks to months without treatment. Diagnosis requires specific stool testing (microscopy or PCR), as routine labs lack Cyclospora detection. First-line therapy is trimethoprim-sulfamethoxazole (TMP-SMX); alternatives (ciprofloxacin, nitazoxanide) are less effective [1][6][13].
Burden
U.S. incidence rose to ~3,000 annual domestically acquired cases (2019–2022), with Texas, Florida, and Illinois disproportionately affected [12][14][18].
Prolonged diarrhea increases hospitalization risk (3%–5% of cases) and complications (malabsorption, cholecystitis) [1][6][14].
Economic impact stems from food recalls, outbreak investigations, and healthcare costs [14][18].
Therapies
First-line: TMP-SMX (160 mg/800 mg) twice daily for 7–10 days; prolonged courses for HIV/AIDS [1][8][13].
Sulfa-allergic patients: Ciprofloxacin (500 mg bid) or nitazoxanide (500 mg bid), though efficacy is reduced [3][8].
Immunocompromised: May require indefinite TMP-SMX prophylaxis post-treatment [13][19].
Categories: rare infectious diseases
Research Papers
36 drug discovery papers about Cyclosporiasis, with 1 first-in-class emerging drug candidates forecasted to outperform the average preclinical success rate. Recent publications:
36 drug discovery papers about Cyclosporiasis, with 1 first-in-class emerging drug candidates forecasted to outperform the average preclinical success rate. Recent publications:
categories:
Small molecules
small molecules
2026-07-30 | Cyclosporiasis Outbreaks in the United States: Epidemiology, Clinical Features, Diagnosis, Treatment, and Prevention
Cyclosporiasis is an intestinal protozoal infection caused by Cyclospora cayetanensis, an emerging foodborne pathogen repeatedly associated with outbreaks linked to fresh produce in the United States. This narrative review summarizes peer-reviewed literature on United States cyclosporiasis outbreaks, emphasizing epidemiologic patterns, clinical manifestations, diagnostic approaches, treatment evidence, and prevention strategies. Published outbreak investigations show that cyclosporiasis in the United States is strongly seasonal, frequently occurring during spring and summer, and has been associated with fresh produce including leafy greens, herbs, berries, and imported or domestically distributed produce. Clinical illness is characterized by prolonged watery diarrhea, abdominal cramping, fatigue, anorexia, weight loss, nausea, and relapse when untreated. Diagnostic confirmation depends on stool examination using modified acid-fast staining, ultraviolet fluorescence, or molecular assays, while traceback investigations increasingly rely on molecular and genomic tools. Trimethoprim-sulfamethoxazole remains the preferred therapy; however, randomized clinical trial evidence is limited, with only a small number of trials supporting parasite eradication and symptom resolution. Evidence for alternative therapies in sulfonamide-intolerant patients is less robust. Prevention requires coordinated farm-to-fork interventions, clinician awareness, rapid reporting, validated produce testing, and improved molecular linkage between cases and food vehicles. Overall, cyclosporiasis remains an important United States food safety challenge because of its long incubation period, produce-associated transmission, and persistent gaps in environmental detection and control.
2026-03-04 | Is hepatotoxicity a potential adverse effect of Sulfamethoxazole/Trimethoprim (SMX/TMP)?
They are a commonly used antimicrobial agent for the treatment of bacterial infections of the urinary tract, otitis media, bronchitis, traveler’s diarrhea, shigellosis, Pneumocystis jirovecii pneumonia (PJP), and community-acquired infections caused by methicillin-resistant Staphylococcus aureus (MRSA).This combination is particularly indicated for the management of bacterial infections in patients with HIV, such as pneumocystis pneumonia (prophylaxis and treatment), isosporiasis, salmonellosis, toxoplasma encephalitis (prophylaxis and treatment). It is also indicated in the management of exacerbations of chronic obstructive pulmonary disease (COPD), pulmonary cystic fibrosis, infections with Aeromonas, infections resulting from animal bites, bacterial endocarditis, bacterial keratitis, meningitis, cholera, cyclosporiasis, diabetic foot infection, diverticulitis, infectious arthritis, osteomyelitis, pertussis, prostatitis, sepsis, and sinusitis.
2026-01-04 | Molecular characterization of human pathogenic Enterocytozoon bieneusi, Giardia duodenalis and Cyclospora cayetanensis of diarrheal outpatients in Yangtze river delta region, China.
Giardia duodenalis, Enterocytozoon bieneusi and Cyclospora cayetanensis are usually classified as Neglected Tropical Diseases, causing giardiasis, microsporidiosis and cyclosporiasis, respectively, which significantly contributed to food- and water-transmitted intestinal illnesses in both humans and animals. In this study, we conducted on the prevalence and molecular characterization of Giardia, E. bieneusi and C. cayetanensis of diarrheal outpatients from three areas in the Yangtze River Delta, China. A total of 2 720 fecal samples were collected and nested PCR was used to identify and describe the genetic characteristic of Giardia, E. bieneusi and C. cayetanensis. The overall prevalence of the three pathogens was 2.54% (69/2 720), with 1.03% for E. bieneusi (28/2 720), 0.8% for G. duodenalis (22/2 720), and 0.7% for C. cayetanensis (19/2 720), respectively. 9 E. bieneusi genotypes, together with two known genotypes A (n = 20) and D (n = 1), and 7 novel genotypes named JDFY-1 to JDFY-7 were identified. All the genotypes were clustered into zoonotic potential Group 1. In addition, 22 G. intestinalis-positive samples were genotyped as assemblages A (n = 4), B (n = 17) and E (n = 1). 19 stool samples were identified to be C. cayetanensis and two new sequences were found. Therefore, our results underscored the existence and importance of E. bieneusi, Giardia and C. cayetanensis in diarrheal outpatients. Furthermore, the findings of E. bieneusi genotypes and new sequences of Giardia and C. cayetanensis indicates a high zoonotic potential of these pathogens in diarrheal outpatients. A broader range of investigations should be conducted on human, animal, and environmental sources to better understand the real transmission routes of the three enteric zoonotic protozoan.
2025-12-31 | Effectiveness of Trimethoprim-Sulfamethoxazole in Cyclosporiasis: A Meta-analysis of Randomized Clinical Trials
Introduction: Cyclosporiasis, caused by Cyclospora cayetanensis, is an intestinal infection transmitted via contaminated food and water and is responsible for at least 10% of diarrheal episodes in children aged 0-4 years in endemic regions. Clinically, it manifests as watery diarrhea, fever, and fatigue, posing significant public health challenges because of its association with foodborne outbreaks and the resultant healthcare costs. The primary treatment regimen involves trimethoprim-sulfamethoxazole (TMP/SMX); however, no meta-analysis has validated its use. Objective: We performed a meta-analysis to evaluate the efficacy of TMP/SMX compared to placebo for the eradication of oocysts and clinical resolution of cyclospora, drawing on data from randomized controlled trials (RCTs). Methods: A comprehensive search was performed in PubMed, Scopus, and Google Scholar until May 2025. The studies deemed eligible were randomized controlled trials (RCTs) that included confirmed diagnoses and clinical or laboratory assessments conducted seven days following treatment. The methodological quality of the studies was evaluated using Cochrane's Risk of Bias 2 (RoB 2) tool. Risk differences (RD) with 95% confidence intervals (CI) were calculated using a random-effects model. Results: Among the 19 studies identified, only three were randomized controlled trials, encompassing 88 patients. The oocyst eradication rates with TMP/SMX ranged from 83% to 100%, in contrast to the persistent infection observed in the placebo group. The reported risk difference (RD) values were −1.00 (Madico et al.), −0.78 (Hoge et al.), and −0.82 (Shim et al) The heterogeneity was moderate, with an I² value of 40%. The risk of bias was low for Hoge et al., moderate for Shim et al., and high for Madico et al. Conclusion: The present meta-analysis demonstrated that TMP/SMX exhibits significant efficacy in eradicating Cyclospora cayetanensis and improving clinical outcomes compared to placebo, thereby supporting its designation as the preferred treatment for Cyclosporainfection. However, the evidence is constrained by the limited number and variable quality of existing trials, underscoring the necessity for larger, high-quality randomized controlled trials (RCTs) to reinforce the therapeutic recommendations.
2025-09-27 | Diagnostic Challenges of Cyclosporiasis in Chronic Diarrhea: A Case Study.
Cyclosporiasis, caused by Cyclospora cayetanensis, is a rare opportunistic infection, particularly in immunosuppressed patients with inflammatory bowel disease (IBD). Its clinical presentation may mimic IBD, with chronic diarrhea and anemia resistant to standard therapy. We report the case of a 24-year-old woman with ulcerative colitis (UC) and a history of liver transplantation, treated with vedolizumab and immunosuppressants. Despite endoscopic remission, she experienced persistent abdominal pain, diarrhea, and iron deficiency anemia. Escalation of biologic therapy was ineffective. After exclusion of bacterial and viral causes, stool testing identified Cyclospora cayetanensis. Treatment with nitazoxanide led to rapid clinical and laboratory improvement. Biologic therapy was temporarily discontinued and later resumed without recurrence of symptoms. This case shows that chronic diarrhea in IBD patients may not always result from the underlying disease. Immunosuppression increases the risk of opportunistic infections. Early diagnosis and specific treatment can improve outcomes and allow safe continuation of IBD therapy.
vaccines
2023-04-04 | Immunogenic multi-epitope-based vaccine development to combat cyclosporiasis of immunocompromised patients applying computational biology method.
Cyclospora cayetanensis infections, also known as cyclosporiasis, persist to be the prevalent emerging protozoan parasite and an opportunist that causes digestive illness in immunocompromised individuals. In contrast, this causal agent can affect people of all ages, with children and foreigners being the most susceptible populations. For most immunocompetent patients, the disease is self-limiting; in extreme circumstances, this illness can manifest as severe or persistent diarrhea as well as colonize on secondary digestive organs leading to death. According to recent reports, worldwide 3.55% of people are infected by this pathogen, with Asia and Africa being more prevalent. For the treatment, trimethoprim-sulfamethoxazole is the only licensed drug and does not appear to work as well in some patient populations. Therefore, the much more effective strategy to avoid this illness is immunization through the vaccine. This present study uses immunoinformatics for identifying a computational multi-epitope-based peptide vaccine candidate for Cyclospora cayetanensis. Following the review of the literature, a highly efficient, secure, and vaccine complex based on multi-epitopes was designed by utilizing the identified proteins. These selected proteins were then used to predict non-toxic and antigenic HTL-epitopes, B-cell-epitopes, and CTL-epitopes. Ultimately, both a few linkers and an adjuvant were combined to create a vaccine candidate with superior immunological epitopes. Then, to establish the vaccine-TLR complex binding constancy, the TLR receptor and vaccine candidates were placed into the FireDock, PatchDock, and ClusPro servers for molecular docking and iMODS server for molecular-dynamic simulation. Finally, this selected vaccine construct was cloned into Escherichia coli strain-K12; thus, the constructed vaccines against Cyclospora cayetanensiscould improve the host immune response and can be produced experimentally.
small molecules
2026-07-30 | Cyclosporiasis Outbreaks in the United States: Epidemiology, Clinical Features, Diagnosis, Treatment, and Prevention
Cyclosporiasis is an intestinal protozoal infection caused by Cyclospora cayetanensis, an emerging foodborne pathogen repeatedly associated with outbreaks linked to fresh produce in the United States. This narrative review summarizes peer-reviewed literature on United States cyclosporiasis outbreaks, emphasizing epidemiologic patterns, clinical manifestations, diagnostic approaches, treatment evidence, and prevention strategies. Published outbreak investigations show that cyclosporiasis in the United States is strongly seasonal, frequently occurring during spring and summer, and has been associated with fresh produce including leafy greens, herbs, berries, and imported or domestically distributed produce. Clinical illness is characterized by prolonged watery diarrhea, abdominal cramping, fatigue, anorexia, weight loss, nausea, and relapse when untreated. Diagnostic confirmation depends on stool examination using modified acid-fast staining, ultraviolet fluorescence, or molecular assays, while traceback investigations increasingly rely on molecular and genomic tools. Trimethoprim-sulfamethoxazole remains the preferred therapy; however, randomized clinical trial evidence is limited, with only a small number of trials supporting parasite eradication and symptom resolution. Evidence for alternative therapies in sulfonamide-intolerant patients is less robust. Prevention requires coordinated farm-to-fork interventions, clinician awareness, rapid reporting, validated produce testing, and improved molecular linkage between cases and food vehicles. Overall, cyclosporiasis remains an important United States food safety challenge because of its long incubation period, produce-associated transmission, and persistent gaps in environmental detection and control.
2026-03-04 | Is hepatotoxicity a potential adverse effect of Sulfamethoxazole/Trimethoprim (SMX/TMP)?
They are a commonly used antimicrobial agent for the treatment of bacterial infections of the urinary tract, otitis media, bronchitis, traveler’s diarrhea, shigellosis, Pneumocystis jirovecii pneumonia (PJP), and community-acquired infections caused by methicillin-resistant Staphylococcus aureus (MRSA).This combination is particularly indicated for the management of bacterial infections in patients with HIV, such as pneumocystis pneumonia (prophylaxis and treatment), isosporiasis, salmonellosis, toxoplasma encephalitis (prophylaxis and treatment). It is also indicated in the management of exacerbations of chronic obstructive pulmonary disease (COPD), pulmonary cystic fibrosis, infections with Aeromonas, infections resulting from animal bites, bacterial endocarditis, bacterial keratitis, meningitis, cholera, cyclosporiasis, diabetic foot infection, diverticulitis, infectious arthritis, osteomyelitis, pertussis, prostatitis, sepsis, and sinusitis.
2026-01-04 | Molecular characterization of human pathogenic Enterocytozoon bieneusi, Giardia duodenalis and Cyclospora cayetanensis of diarrheal outpatients in Yangtze river delta region, China.
Giardia duodenalis, Enterocytozoon bieneusi and Cyclospora cayetanensis are usually classified as Neglected Tropical Diseases, causing giardiasis, microsporidiosis and cyclosporiasis, respectively, which significantly contributed to food- and water-transmitted intestinal illnesses in both humans and animals. In this study, we conducted on the prevalence and molecular characterization of Giardia, E. bieneusi and C. cayetanensis of diarrheal outpatients from three areas in the Yangtze River Delta, China. A total of 2 720 fecal samples were collected and nested PCR was used to identify and describe the genetic characteristic of Giardia, E. bieneusi and C. cayetanensis. The overall prevalence of the three pathogens was 2.54% (69/2 720), with 1.03% for E. bieneusi (28/2 720), 0.8% for G. duodenalis (22/2 720), and 0.7% for C. cayetanensis (19/2 720), respectively. 9 E. bieneusi genotypes, together with two known genotypes A (n = 20) and D (n = 1), and 7 novel genotypes named JDFY-1 to JDFY-7 were identified. All the genotypes were clustered into zoonotic potential Group 1. In addition, 22 G. intestinalis-positive samples were genotyped as assemblages A (n = 4), B (n = 17) and E (n = 1). 19 stool samples were identified to be C. cayetanensis and two new sequences were found. Therefore, our results underscored the existence and importance of E. bieneusi, Giardia and C. cayetanensis in diarrheal outpatients. Furthermore, the findings of E. bieneusi genotypes and new sequences of Giardia and C. cayetanensis indicates a high zoonotic potential of these pathogens in diarrheal outpatients. A broader range of investigations should be conducted on human, animal, and environmental sources to better understand the real transmission routes of the three enteric zoonotic protozoan.
2025-12-31 | Effectiveness of Trimethoprim-Sulfamethoxazole in Cyclosporiasis: A Meta-analysis of Randomized Clinical Trials
Introduction: Cyclosporiasis, caused by Cyclospora cayetanensis, is an intestinal infection transmitted via contaminated food and water and is responsible for at least 10% of diarrheal episodes in children aged 0-4 years in endemic regions. Clinically, it manifests as watery diarrhea, fever, and fatigue, posing significant public health challenges because of its association with foodborne outbreaks and the resultant healthcare costs. The primary treatment regimen involves trimethoprim-sulfamethoxazole (TMP/SMX); however, no meta-analysis has validated its use. Objective: We performed a meta-analysis to evaluate the efficacy of TMP/SMX compared to placebo for the eradication of oocysts and clinical resolution of cyclospora, drawing on data from randomized controlled trials (RCTs). Methods: A comprehensive search was performed in PubMed, Scopus, and Google Scholar until May 2025. The studies deemed eligible were randomized controlled trials (RCTs) that included confirmed diagnoses and clinical or laboratory assessments conducted seven days following treatment. The methodological quality of the studies was evaluated using Cochrane's Risk of Bias 2 (RoB 2) tool. Risk differences (RD) with 95% confidence intervals (CI) were calculated using a random-effects model. Results: Among the 19 studies identified, only three were randomized controlled trials, encompassing 88 patients. The oocyst eradication rates with TMP/SMX ranged from 83% to 100%, in contrast to the persistent infection observed in the placebo group. The reported risk difference (RD) values were −1.00 (Madico et al.), −0.78 (Hoge et al.), and −0.82 (Shim et al) The heterogeneity was moderate, with an I² value of 40%. The risk of bias was low for Hoge et al., moderate for Shim et al., and high for Madico et al. Conclusion: The present meta-analysis demonstrated that TMP/SMX exhibits significant efficacy in eradicating Cyclospora cayetanensis and improving clinical outcomes compared to placebo, thereby supporting its designation as the preferred treatment for Cyclosporainfection. However, the evidence is constrained by the limited number and variable quality of existing trials, underscoring the necessity for larger, high-quality randomized controlled trials (RCTs) to reinforce the therapeutic recommendations.
2025-09-27 | Diagnostic Challenges of Cyclosporiasis in Chronic Diarrhea: A Case Study.
Cyclosporiasis, caused by Cyclospora cayetanensis, is a rare opportunistic infection, particularly in immunosuppressed patients with inflammatory bowel disease (IBD). Its clinical presentation may mimic IBD, with chronic diarrhea and anemia resistant to standard therapy. We report the case of a 24-year-old woman with ulcerative colitis (UC) and a history of liver transplantation, treated with vedolizumab and immunosuppressants. Despite endoscopic remission, she experienced persistent abdominal pain, diarrhea, and iron deficiency anemia. Escalation of biologic therapy was ineffective. After exclusion of bacterial and viral causes, stool testing identified Cyclospora cayetanensis. Treatment with nitazoxanide led to rapid clinical and laboratory improvement. Biologic therapy was temporarily discontinued and later resumed without recurrence of symptoms. This case shows that chronic diarrhea in IBD patients may not always result from the underlying disease. Immunosuppression increases the risk of opportunistic infections. Early diagnosis and specific treatment can improve outcomes and allow safe continuation of IBD therapy.
vaccines
2023-04-04 | Immunogenic multi-epitope-based vaccine development to combat cyclosporiasis of immunocompromised patients applying computational biology method.
Cyclospora cayetanensis infections, also known as cyclosporiasis, persist to be the prevalent emerging protozoan parasite and an opportunist that causes digestive illness in immunocompromised individuals. In contrast, this causal agent can affect people of all ages, with children and foreigners being the most susceptible populations. For most immunocompetent patients, the disease is self-limiting; in extreme circumstances, this illness can manifest as severe or persistent diarrhea as well as colonize on secondary digestive organs leading to death. According to recent reports, worldwide 3.55% of people are infected by this pathogen, with Asia and Africa being more prevalent. For the treatment, trimethoprim-sulfamethoxazole is the only licensed drug and does not appear to work as well in some patient populations. Therefore, the much more effective strategy to avoid this illness is immunization through the vaccine. This present study uses immunoinformatics for identifying a computational multi-epitope-based peptide vaccine candidate for Cyclospora cayetanensis. Following the review of the literature, a highly efficient, secure, and vaccine complex based on multi-epitopes was designed by utilizing the identified proteins. These selected proteins were then used to predict non-toxic and antigenic HTL-epitopes, B-cell-epitopes, and CTL-epitopes. Ultimately, both a few linkers and an adjuvant were combined to create a vaccine candidate with superior immunological epitopes. Then, to establish the vaccine-TLR complex binding constancy, the TLR receptor and vaccine candidates were placed into the FireDock, PatchDock, and ClusPro servers for molecular docking and iMODS server for molecular-dynamic simulation. Finally, this selected vaccine construct was cloned into Escherichia coli strain-K12; thus, the constructed vaccines against Cyclospora cayetanensiscould improve the host immune response and can be produced experimentally.
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