Current Intestinal Protozoal Infections: Diagnosis, Treatment, Prevention
DOI:
https://doi.org/10.11603/1681-2727.2026.2.16504Keywords:
protozoan infections, blastocystosis, giardiasis, cryptosporidiosis, diagnosis, treatment, prevention, intestinal parasitoses, Blastocystis spp., Giardia duodenalis, Cryptosporidium sppAbstract
SUMMARY. The article presents current data on the most common human intestinal protozoan infections, including blastocystosis, giardiasis, and cryptosporidiosis. Their epidemiological characteristics, sources of infection, transmission routes, pathogenesis, and clinical manifestations are analyzed. Particular attention is paid to the current distribution of these diseases worldwide and in Ukraine, as well as to populations at increased risk. Modern laboratory diagnostic approaches, including microscopic, immunological, and molecular genetic methods, are reviewed with emphasis on their diagnostic value and practical applicability. Contemporary treatment strategies for blastocystosis, giardiasis, and cryptosporidiosis are summarized, including the main antiprotozoal agents and their clinical use. Preventive measures aimed at interrupting fecal–oral transmission, ensuring safe water supply, improving sanitation and hygiene, and implementing the One Health concept are discussed. The need to improve epidemiological surveillance and laboratory diagnosis of protozoan infections in Ukraine is emphasized.
References
Abaka-Yawson, A., Squire, D. S., Issah, I., Ablordey, K., Ativi, E., Bawua, S. A., & Arko-Mensah, J. (2025). Global prevalence and associated factors of intestinal parasitic infections among institutionalized populations: a systematic review and meta-analysis. BMC Infectious Diseases. https://doi.org/10.1186/s12879-025-12228-z DOI: https://doi.org/10.1186/s12879-025-12228-z
Alasil, S. M., & Abdullah, K. A. (2019). An epidemiological review on emerging and re-emerging parasitic infectious diseases in Malaysia. The Open Microbiology Journal, 13, 112–120. https://doi.org/10.2174/1874285801913010112 DOI: https://doi.org/10.2174/1874285801913010112
Abdoli, A., Olfatifar, M., Eslahi, A. V., Moghadamizad, Z., Samimi, R., Habibi, M. A., Kianimoghadam, A. S., Badri, M., & Karanis, P. (2024). A systematic review and meta-analysis of protozoan parasite infections among patients with mental health disorders: An overlooked phenomenon. Gut Pathogens, 16(1), Article 7. https://doi.org/10.1186/s13099-024-00602-2 DOI: https://doi.org/10.1186/s13099-024-00602-2
Kaminsky, R., & Mäser, P. (2025). Global impact of parasitic infections and the importance of parasite control. Frontiers in Parasitology, 4, Article 1546195. https://doi.org/10.3389/fpara.2025.1546195 DOI: https://doi.org/10.3389/fpara.2025.1546195
Sánchez, A., Munoz, M., Gómez, N., Tabares, J., Segura, L., Salazar, Á., Restrepo, C., Ruíz, M., Reyes, P., Qian, Y., Xiao, L., López, M. C., & Ramírez, J. D. (2017). Molecular epidemiology of Giardia, Blastocystis and Cryptosporidium among indigenous children from the Colombian Amazon Basin. Frontiers in Microbiology, 8, Article 248. https://doi.org/10.3389/fmicb.2017.00248 DOI: https://doi.org/10.3389/fmicb.2017.00248
Seid, M., Yohanes, T., Goshu, Y., Jemal, K., & Siraj, M. (2022). The effect of compliance to hand hygiene during COVID-19 on intestinal parasitic infection and intensity of soil-transmitted helminths among patients attending a general hospital in southern Ethiopia: Observational study. PLoS ONE, 17(6), Article e0270378. https://doi.org/10.1371/journal.pone.0270378 DOI: https://doi.org/10.1371/journal.pone.0270378
Міністерство охорони здоров’я України. (2025). Інфекційна захворюваність населення України за вересень та 9 місяців 2024–2025 рр. Центр громадського здоров’я МОЗ України. https://phc.org.ua/kontrol-zakhvoryuvan/inshi-infekciyni-zakhvoryuvannya/infekciyna
Vielma, J. R. (2019). Blastocystosis: Epidemiological, clinical, pathogenic, diagnostic, and therapeutic aspects. Investigación Clínica, 60(1), 53–78. https://doi.org/10.22209/IC.v60n1a06 DOI: https://doi.org/10.22209/IC.v60n1a06
Stensvold, C. R., Tan, K. S. W., & Clark, C. G. (2020). Blastocystis. Trends in Parasitology, 36(3), 315–316. https://doi.org/10.1016/j.pt.2019.12.008 DOI: https://doi.org/10.1016/j.pt.2019.12.008
Deng, L., Wojciech, L., Gascoigne, N. R. J., Peng, G., & Tan, K. S. W. (2021). New insights into the interactions between Blastocystis, the gut microbiota, and host immunity. PLoS Pathogens, 17(2), Article e1009253. https://doi.org/10.1371/journal.ppat.1009253 DOI: https://doi.org/10.1371/journal.ppat.1009253
Öztürk, E. A., Guadano-Procesi, I., Figueiredo, A. M., Godfrey, A., Gentekaki, E., Tsaousis, A. D., ... & Dogruman-Al, F. (2025). A protocol for mapping Blastocystis epidemiology and diagnostics from One Health perspective. Open Research Europe, 5, 133. https://doi.org/10.12688/openreseurope.19595.1 DOI: https://doi.org/10.12688/openreseurope.20151.1
Sheishaa, G. A. A., Ahmad, H. K., Abdelhameed, K., & Ali, N. E. (2023). Blastocystis species prevalence and associated patient characteristics as predictors among a cohort of symptomatic and asymptomatic Egyptians. Al-Azhar International Medical Journal, 4(3), 112–118. https://doi.org/10.58675/2682-339X.1712 DOI: https://doi.org/10.21608/aimj.2025.159881.2139
Shahinian, V. R., Filchakov, I. V., Danko, O. P., Sopil, H. V., & Diachenko, O. P. (2020). Клініко-епідеміологічні особливості паразитарної інвазії Blastocystis spp. Інфекційні хвороби, 3, 84–90. https://doi.org/10.11603/1681-2727.2020.3.11556 DOI: https://doi.org/10.11603/1681-2727.2020.3.11556
Yowang, A., Tsaousis, A. D., Chumphonsuk, T., Thongsin, N., Kullawong, N., Popluechai, S., & Gentekaki, E. (2018). High diversity of Blastocystis subtypes isolated from asymptomatic adults living in Chiang Rai, Thailand. Infection, Genetics and Evolution, 65, 270-275. https://doi.org/10.1016/j.meegid.2018.08.010 DOI: https://doi.org/10.1016/j.meegid.2018.08.010
Jinatham, V., Maxamhud, S., Popluechai, S., Tsaousis, A. D., & Gentekaki, E. (2021). Blastocystis One Health approach in a rural community of northern Thailand: Prevalence, subtypes and novel transmission routes. Frontiers in Microbiology, 12, Article 746340. https://doi.org/10.3389/fmicb.2021.746340 DOI: https://doi.org/10.3389/fmicb.2021.746340
Shaari, N. S. M., Abdullah, N. S., Lee, I. L., Omar, R., Wan Sulaiman, W. S., & Mohamad Nor, N. U. (2022). Blastocystis sp. subtypes colonisation and their association with clinical diseases: A systematic review. ASM Science Journal, 17, 1–23. https://doi.org/10.32802/asmscj.2022.959 DOI: https://doi.org/10.32802/asmscj.2022.959
Stensvold, C. R., & Clark, C. G. (2016). Current status of Blastocystis: A personal view. Parasitology International, 65(6 Pt B), 763–771. https://doi.org/10.1016/j.parint.2016.05.015 DOI: https://doi.org/10.1016/j.parint.2016.05.015
Кіриченко, І., Бірюков, М., Похил, С., & Тимченко, О. (2025). Бластоцистоз: Епідеміологія і клінічні прояви (інформаційний лист). Анали Мечниковського Інституту, 3, 107–108. https://doi.org/10.5281/zenodo.17105732
Hatam-Nahavandi, K., Ahmadpour, E., Badri, M., Eslahi, A. V., Anvari, D., Carmena, D., & Xiao, L. (2025). Global prevalence of Giardia infection in nonhuman mammalian hosts: A systematic review and meta-analysis of five million animals. PLoS Neglected Tropical Diseases, 19(4), Article e0013021. https://doi.org/10.1371/journal.pntd.0013021 DOI: https://doi.org/10.1371/journal.pntd.0013021
European Centre for Disease Prevention and Control. (2024). Giardiasis: Annual epidemiological report for 2022. https://www.ecdc.europa.eu/en/publications-data/giardiasis-annual-epidemiological-report-2022Центр громадського здоров’я Міністерства охорони здоров’я України. (2025). Звіт про інфекційні та паразитарні хвороби за грудень та 12 місяців 2024–2025 рр. (форма № 1) [PDF]. https://phc.org.ua/sites/default/files/users/user159/%D0%A4%D0%BE%D1%80%D0%BC%D0%B0%201/%D0%97%D0%B2%D1%96%D1%82%20%D0%BF%D1%80%D0%BE%20%D1%96%D0%BD%D1%84.%20%D1%82%D0%B0%20%D0%BF%D0%B0%D1%80%D0%B0%D0%B7%D0%B8%D1%82.%20%D1%85%D0%B2%D0%BE%D1%80.%20%D0%B7%D0%B0%2012.2025%20%D1%82%D0%B0%2012%20%D0%BC%D1%96%D1%81.%202024-2025%20%28%D1%84%D0%BE%D1%80%D0%BC%D0%B0%20%E2%84%961%29.pdf
Adam, R. D. (2021). Giardia duodenalis: Biology and pathogenesis. Clinical Microbiology Reviews, 34(4), e00024-19. https://doi.org/10.1128/CMR.00024-19 DOI: https://doi.org/10.1128/CMR.00024-19
Leung, A. K. C., Leung, A. A. M., Wong, A. H. C., Sergi, C. M., & Kam, J. K. M. (2019). Giardiasis: An overview. Recent Patents on Inflammation & Allergy Drug Discovery, 13(2), 134–143. https://doi.org/10.2174/1872213X13666190618124901 DOI: https://doi.org/10.2174/1872213X13666190618124901
Gunawan, I. M., Athiyyah, A. F., & Arwati, H. (2025). Giardia lamblia infection: A review of the current literature. World Journal of Advanced Research and Reviews, 28(2), 126–130. https://doi.org/10.30574/wjarr.2025.28.2.3715 DOI: https://doi.org/10.30574/wjarr.2025.28.2.3715
Allain, T., & Buret, A. G. (2020). Pathogenesis and post-infectious complications in giardiasis. In Giardia and Giardiasis, Part B (pp. 173–199). Elsevier. https://doi.org/10.1016/bs.apar.2019.12.001 DOI: https://doi.org/10.1016/bs.apar.2019.12.001
Heyworth, M. F. (2014). Immunological aspects of Giardia infections. Parasite, 21, Article 55. https://doi.org/10.1051/parasite/2014056 DOI: https://doi.org/10.1051/parasite/2014056
Centers for Disease Control and Prevention. (2024, June 5). DPDx–Giardiasis. U.S. Department of Health and Human Services. https://www.cdc.gov/dpdx/giardiasis/index.html
Greenwald, B. D. (2024, February 16). Giardiasis clinical presentation: History, physical examination. Medscape. https://emedicine.medscape.com/article/176718-clinical
Naser, O. A. S., Ismai, M. A., Al-Abbas, W. D. S., & Al-Fahham, A. A. (2024). Giardiasis: Diagnosis, pathogenesis and treatment. International Journal of Health & Medical Research, 3(6). https://doi.org/10.58806/ijhmr.2024.v3i06n28 DOI: https://doi.org/10.58806/ijhmr.2024.v3i06n28
Belkessa, S., Ait-Salem, E., Laatamna, A., Houali, K., Sönksen, U. W., Hakem, A., Bouchene, Z., Ghalmi, F., & Stensvold, C. R. (2021). Prevalence and clinical manifestations of Giardia intestinalis and other intestinal parasites in children and adults in Algeria. The American Journal of Tropical Medicine and Hygiene, 104(3), 910–916. https://doi.org/10.4269/ajtmh.20-0187 DOI: https://doi.org/10.4269/ajtmh.20-0187
Santos, J. V. I., Silva, W. I., Lima Neto, B. F., Feitosa, T. F., & Vilela, V. L. R. (2025). Epidemiology of human cryptosporidiosis in Brazil: A systematic review highlighting Cryptosporidium parvum. Tropical Medicine and Infectious Disease, 10(11), Article 313. https://doi.org/10.3390/tropicalmed10110313 DOI: https://doi.org/10.3390/tropicalmed10110313
Widodo, W. T., Khairullah, A. R., Pratama, B. P., Ambarika, R., Furqoni, A. H., Kristianto, S., Wardhani, B. W. K., Widoretno, W., Khariri, K., Hermawati, L., Suri, A. A., Moses, I. B., Putri, A. K., Kurniasih, D. A. A., Maha, M. S., Khalisa, A. T., Ahmad, R. Z., & Wibowo, S. (2025). Cryptosporidiosis: A global threat to human and animal health. Open Veterinary Journal, 15(10), 4814–4833. https://doi.org/10.5455/OVJ.2025.v15.i10.3 DOI: https://doi.org/10.5455/OVJ.2025.v15.i10.3
Khalil, I. A., Troeger, C., Rao, P. C., Blacker, B. F., Brown, A., Brewer, T. G., Colombara, D. V., De Hostos, E. L., Engmann, C., Guerrant, R. L., Haque, R., Houpt, E. R., Kang, G., Korpe, P. S., Kotloff, K. L., Lima, A. A. M., Petri, W. A., Jr., Platts-Mills, J. A., Shoultz, D. A., Forouzanfar, M. H., Hay, S. I., Reiner, R. C., Jr., & Mokdad, A. H. (2018). Morbidity, mortality, and long-term consequences associated with diarrhoea from Giardia infection in children younger than 5 years: A systematic analysis. The Lancet Global Health, 6(7), e758–e768. https://doi.org/10.1016/S2214-109X(18)30283-3 DOI: https://doi.org/10.1016/S2214-109X(18)30283-3
Centers for Disease Control and Prevention. (2025, September 11). Cryptosporidiosis NNDSS summary report for 2022. U.S. Department of Health and Human Services. https://www.cdc.gov/healthy-water-data/documentation/cryptosporidiosis-nndss-summary-report-for-2022.html
European Centre for Disease Prevention and Control. (2024). Cryptosporidiosis: Annual epidemiological report for 2021. ECDC. https://www.ecdc.europa.eu/en/publications-data/cryptosporidiosis-annual-epidemiological-report-2021
UK Health Security Agency. (2025). Cryptosporidium data: 2015 to 2024. GOV.UK. https://www.gov.uk/government/publications/cryptosporidium-national-laboratory-data/cryptosporidium-data-2015-to-2024
Рівненський обласний центр контролю та профілактики хвороб МОЗ України. (2024, June 11). Криптоспоридіоз – паразитарна інфекція: як розпізнати? https://rv.cdc.gov.ua/news/kryptosporydioz-parazytarna-infektsiya-yak-rozpiznaty/
Xiao, L. (2010). Molecular epidemiology of cryptosporidiosis: An update. Experimental Parasitology, 124(1), 80–89. https://doi.org/10.1016/j.exppara.2009.03.018 DOI: https://doi.org/10.1016/j.exppara.2009.03.018
Gerace, E., Lo Presti, V. D. M., & Biondo, C. (2019). Cryptosporidium infection: Epidemiology, pathogenesis, and differential diagnosis. European Journal of Microbiology and Immunology, 9(4), 119–123. https://doi.org/10.1556/1886.2019.00019 DOI: https://doi.org/10.1556/1886.2019.00019
Porter, R. S., & Petri, W. A., Jr. (2024). Cryptosporidiosis. In MSD Manual Professional Edition. Merck Sharp & Dohme LLC. https://www.msdmanuals.com/professional/infectious-diseases/intestinal-protozoa-and-microsporidia/cryptosporidiosis
Соломаха, К. В. (2020). Криптоспоридії – небезпечні паразити у воді басейнів та аквапарків. Young Scientist, 2(78). https://doi.org/10.32839/2304-5809/2020-2-78-16Reina, F. T., Ribeiro, C. A., Araújo, R. S., Matté, M. H., Castanho, R. E., Tanaka, I. I., Viggiani, A. M., & Martins, L. P. (2016). Intestinal and pulmonary infection by Cryptosporidium parvum in two patients with HIV/AIDS. Revista do Instituto de Medicina Tropical de São Paulo, 58, Article 21. https://doi.org/10.1590/S1678-9946201658021 DOI: https://doi.org/10.1590/S1678-9946201658021
Kumar, A., Chatterjee, I., Anbazhagan, A. N., Jayawardena, D., Priyamvada, S., Alrefai, W. A., ... & Dudeja, P. K. (2018). Cryptosporidium parvum disrupts intestinal epithelial barrier function via altering expression of key tight junction and adherens junction proteins. Cellular Microbiology, 20(6), e12830. https://doi.org/10.1111/cmi.12830 DOI: https://doi.org/10.1111/cmi.12830
Ali, M., Xu, C., Ji, Y., & Li, K. (2025). Host immune response to Cryptosporidium spp.: Insights and perspectives for vaccine development. Animals and Zoonoses. https://doi.org/10.1016/j.azn.2025.01.005 DOI: https://doi.org/10.1016/j.azn.2025.01.005
Centers for Disease Control and Prevention. (2025, June 16). Symptoms of Crypto. U.S. Department of Health and Human Services. https://www.cdc.gov/cryptosporidium/signs-symptoms/index.html
Wang, R.-J., Li, J.-Q., Chen, Y.-C., Zhang, L.-X., & Xiao, L.-H. (2018). Widespread occurrence of Cryptosporidium infections in patients with HIV/AIDS: Epidemiology, clinical feature, diagnosis, and therapy. Acta Tropica, 187, 257–263. https://doi.org/10.1016/j.actatropica.2018.08.018 DOI: https://doi.org/10.1016/j.actatropica.2018.08.018
Shane, A. L., Mody, R. K., Crump, J. A., Tarr, P. I., Steiner, T. S., Kotloff, K., Langley, J. M., Wanke, C., Warren, C. A., Cheng, A. C., Cantey, J., & Pickering, L. K. (2017). 2017 Infectious Diseases Society of America clinical practice guidelines for the diagnosis and management of infectious diarrhea. Clinical Infectious Diseases, 65(12), e45–e80. https://doi.org/10.1093/cid/cix669 DOI: https://doi.org/10.1093/cid/cix669
Mohammad, N. A., Mastuki, M. F., Al-Mekhlafi, H. M., Moktar, N., & Anuar, T. S. (2018). Comparative study of Wheatley’s trichrome stain and in-vitro culture against PCR assay for the diagnosis of Blastocystis sp. in stool samples. Iranian Journal of Parasitology, 13(1), 127.
Centers for Disease Control and Prevention. (2024, March 20). Clinical care of blastocystosis. U.S. Department of Health and Human Services. https://www.cdc.gov/blastocystis/hcp/clinical-care/index.html
Pawelec-Pęciak, O., Łanocha-Arendarczyk, N., Grzeszczak, K., & Kosik-Bogacka, D. (2025). The role of Blastocystis spp. in the etiology of gastrointestinal and autoimmune diseases. Pathogens, 14(4), Article 313. https://doi.org/10.3390/pathogens14040313 DOI: https://doi.org/10.3390/pathogens14040313
Roberts, T., Ellis, J., Harkness, J., Marriott, D., & Stark, D. (2014). Treatment failure in patients with chronic Blastocystis infection. Journal of Medical Microbiology, 63(2), 252–257. https://doi.org/10.1099/jmm.0.065508-0 DOI: https://doi.org/10.1099/jmm.0.065508-0
Kot, K., Michaliszyn, A., Kalisińska, E., & Lepczyńska, M. (2024). The influence of plant extracts on viability of ST3 and ST7 subtypes of Blastocystis sp. Gut Pathogens, 16, Article 19. https://doi.org/10.1186/s13099-024-00618-8 DOI: https://doi.org/10.1186/s13099-024-00618-8
Centers for Disease Control and Prevention. (2024, February 20). Patient care for Giardia infection. U.S. Department of Health and Human Services. https://www.cdc.gov/giardia/hcp/clinical-care/index.html
Marie, C., Petri, W. A., Jr., & Muzny, C. A. (2024). Giardiasis. In MSD Manual Professional Edition. Merck Sharp & Dohme LLC. https://www.msdmanuals.com/professional/infectious-diseases/intestinal-protozoa-and-microsporidia/giardiasis
Dunn, N., & Juergens, A. L. (2025). Giardiasis. In StatPearls. StatPearls Publishing. https://www.ncbi.nlm.nih.gov/books/NBK513239/
Darlan, D. M., Hartanto, S. J., & Fakhrur Rozi, M. (2025). The comparison of efficacy and side effect between albendazole and metronidazole in the management of giardiasis: A systematic review and meta-analysis. EuroMediterranean Biomedical Journal, 15. https://doi.org/10.3269/1970-5492.2020.15.45 DOI: https://doi.org/10.3269/1970-5492.2020.15.45
Atnafu, T. A., Usman, A. W., Azerefegne, E. F., & Shemsu, E. S. (2025). Giardiasis: Report of a case refractory to treatment. Clinical Case Reports, 13, e70109. https://doi.org/10.1002/ccr3.70109 DOI: https://doi.org/10.1002/ccr3.70109
Ahmed, M. (2023). Intestinal parasitic infections in 2023. Gastroenterology Research, 16, 127–140. https://doi.org/10.14740/gr1622 DOI: https://doi.org/10.14740/gr1622
Buchanan, R., Wieckowski, P., Matechou, E., Katzer, F., Tsaousis, A. D., & Farré, M. (2025). Global prevalence of Cryptosporidium infections in cattle: A meta-analysis. Current Research in Parasitology & Vector-Borne Diseases, 7, 100264. https://doi.org/10.1016/j.crpvbd.2025.100264 DOI: https://doi.org/10.1016/j.crpvbd.2025.100264
Centers for Disease Control and Prevention. (2024, September 4). About Blastocystis. U.S. Department of Health and Human Services. https://www.cdc.gov/blastocystis/about/index.html
Engineer Fix. (2025). How water treatment removes Cryptosporidium oocysts. https://engineerfix.com/how-water-treatment-removes-cryptosporidium-oocysts/
Centers for Disease Control and Prevention. (2024, September 4). About Giardia infection. U.S. Department of Health and Human Services. https://www.cdc.gov/giardia/about/index.html
Centers for Disease Control and Prevention. (2025, July 7). Preventing and controlling Crypto at childcare facilities. U.S. Department of Health and Human Services. https://www.cdc.gov/cryptosporidium/prevention/preventing-and-controlling-crypto-childcare-facilities.html
Downloads
Published
Issue
Section
License
Copyright (c) 2026 Mykhaylo Andreychyn, Mariia Shkilna, Oleh Ivakhiv, Mariana Huk
This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.
Автори, які публікуються у цьому журналі, погоджуються з наступними умовами:
- Автори залишають за собою право на авторство своєї роботи та передають журналу право першої публікації цієї роботи, яка через [ВКАЖІТЬ ПЕРІОД ЧАСУ] з дати публікації автоматично стає доступною на умовах ліцензії Creative Commons Attribution License, котра дозволяє іншим особам вільно розповсюджувати опубліковану роботу з обов'язковим посиланням на авторів оригінальної роботи та першу публікацію роботи у цьому журналі.
- Автори мають право укладати самостійні додаткові угоди щодо неексклюзивного розповсюдження роботи у тому вигляді, в якому вона була опублікована цим журналом (наприклад, розміщувати роботу в електронному сховищі установи або публікувати у складі монографії), за умови збереження посилання на першу публікацію роботи у цьому журналі.
Політика журналу дозволяє і заохочує розміщення авторами в мережі Інтернет (наприклад, у сховищах установ або на особистих веб-сайтах) рукопису роботи, як до подання цього рукопису до редакції, так і під час його редакційного опрацювання, оскільки це сприяє виникненню продуктивної наукової дискусії та позитивно позначається на оперативності та динаміці цитування опублікованої роботи (див. The Effect of Open Access).
