Bioscience Journal | 2022 | vol. 38, e38001 | ISSN 1981-3163 1 Tarciane Lilia dos SANTOS1 , Antônio de Pádua Medeiros de CARVALHO NETO2 , José Rodrigo da Silva FERREIRA1 , Paulo Victor Muniz AZEVEDO2 , Karwhory Wallas Lins da SILVA3 , Cícera Maria Alencar dos NASCIMENTO4 , Claudia Maria Lins CALHEIROS5 , Flaviana Santos WANDERLEY6 , Marília Gabriela dos Santos CAVALCANTI5 , Mabel Alencar do Nascimento ROCHA7 , Thiago José MATOS-ROCHA6 1 Graduate Course in Medicine, State University of Health Sciences of Alagoas, Maceió, Alagoas, Brazil. 2 Graduate Course in Medicine, Cesmac University Center, Maceió, Alagoas, Brazil. 3 Graduate Course in Biomedicine and Pharmacy, Cesmac University Center, Maceió, Alagoas, Brazil. 4 Postgraduate Program in Environmental Systems Analysis, Cesmac University Center, Maceió, Alagoas, Brazil. 5 Department of Physiology and Pathology, Federal University of Paraíba, João Pessoa, Paraíba, Brazil. 6 Biological Sciences Center, State University of Health Sciences of Alagoas, Maceió, Alagoas, Brazil. 7 Technology Teaching Center, State University of Health Sciences of Alagoas, Maceió, Alagoas, Brazil. Corresponding author: Thiago José Matos Rocha Email: thiago.matos@uncisal.edu.br How to cite: SANTOS, T.L., et al. Frequency of intestinal protozoan infections diagnosed in patients from a clinical analysis laboratory. Bioscience Journal. 2022, 38, e38001. https://doi.org/10.14393/BJ-v38n0a2022-42370 Abstract This study aimed to determine the frequency of infection by intestinal protozoa diagnosed in patients from a clinical analysis laboratory in Maceió, Alagoas, Brazil. This was a retrospective descriptive study, using a database of stool examination results from July to December 2015. The study population consisted of males and females of all ages, from the greater area of Alagoas. Data on epidemiological variables such as age and gender were obtained using a collection instrument. Protozoan species were identified from stool examinations. Results on the prevalence of intestinal parasites are described as simple and relative frequencies. We examined a total of 1277 stool samples, of which 12.69% were positive for one or more protozoa. 43.83% were from men and 56.17% were from women. Endolimax nana was the most prevalent (59.22%) protozoan species followed by Entamoeba coli (23.45%). Although non-pathogenic, they indicate fecal contamination of drinking water. The highest number (23.46%) of infected individuals was observed among children in the 0 to 11 years age group. A high prevalence (93.83%) of monoparasitism was noted. We concluded that there was a high frequency of infection and a high prevalence of E. nana. Infections were more common in women than in men. Our results emphasize the need for preventive measures to control intestinal parasitic infections. Keywords: Epidemiology. Parasitic Diseases. Protozoan Infections. 1. Introduction Intestinal parasitosis is an infection caused by protozoa or helminths. At a specific stage of their biological life cycles, these parasites attach to and live within the human intestine. The fecal-oral route of transmission is the most common. However, infection may also occur through food, water, or flying insects, and is associated with sanitation and hygiene facilities in the community (Thamizhmani et al. 2017). FREQUENCY OF INTESTINAL PROTOZOAN INFECTIONS DIAGNOSED IN PATIENTS FROM A CLINICAL ANALYSIS LABORATORY https://orcid.org/0000-0002-5833-9627 https://orcid.org/0000-0002-8657-0623 https://orcid.org/0000-0002-5918-6247 https://orcid.org/0000-0002-6974-9410 https://orcid.org/0000-0001-7015-2489 https://orcid.org/0000-0003-3046-7798 https://orcid.org/0000-0002-3597-322X https://orcid.org/0000-0001-6922-4174 https://orcid.org/0000-0003-0131-0097 https://orcid.org/0000-0002-7769-5002 https://orcid.org/0000-0001-5153-6583 Bioscience Journal | 2022 | vol. 38, e38001 | https://doi.org/10.14393/BJ-v38n0a2022-42370 2 Frequency of intestinal protozoan infections diagnosed in patients from a clinical analysis laboratory Intestinal parasitic infections are an ongoing serious public health problem worldwide, that needs to be addressed. In Brazil, slow economic development, lack of basic sanitation and hygiene facilities, and poor living conditions are risk factors associated with approximately 51% of the population being infected with at least one species of intestinal parasites (Prieto-Pérez et al. 2016). An estimated 2.5 billion people are infected globally by intestinal parasites. In Brazil, millions of people are infected with at least one species of parasite (possibly helminths or protozoa). Several infected individuals reside in areas that lack basic sanitation facilities and are considered to be of low socioeconomic status (Soares et al. 2018). Etiological agents reported to be involved in transmission include Entamoeba histolytica/Entamoeba dispar, Giardia lamblia, Endolimax nana, Iodamoeba buetschlii (Pajira et al. 2017). Patients commonly develop complications such as chronic malnutrition, diarrhea, nausea and vomiting, protein loss, bowel obstruction and colitis, iron deficiency anemia, and reduced physical activity (Turner et al. 2016). The precariousness of health is evident from the lack of knowledge regarding personal hygiene, sanitation, and other factors (Pullan et al. 2014). Intestinal parasitosis is one of the primary causes of nutrient malabsorption. Parasites have an exploitative relationship with their hosts. They deplete nutrients from host tissues, causing malnutrition and prolonged diarrhea that affects the nutritional status of the host (Pajira et al. 2017). Despite existing data and research on the effect of parasitic infections on human health, there is a lack of public investment and educational programs such as extension projects, aimed at controlling its rising incidence (Humphries et al. 2017). Intestinal parasitosis is considered a minor issue and therefore neglected by healthcare services. Consequently, healthcare agencies also neglect the harmful effects on intellectual and physical development, as well as mortality resulting from parasitic infections (Anselmi et al. 2015). Few papers have been published on the prevalence of intestinal parasites in the State of Alagoas (AL) in Brazil. Rocha et al. (2019) examined 2,194 stool samples from the municipality of Pilar, AL. 67.14% of samples were positive, representing a broad age distribution, and high frequency of Entamoeba histolytica/Entamoeba dispar. Bezerra et al. (2019) assessed 1,336 individuals from the municipality of Atalaia, AL. 2.7% were positive for at least one species of intestinal parasites, with a high frequency of Entamoeba coli. Considering the importance of prevention and early treatment of this disease, we aimed to evaluate the frequency of intestinal protozoa detected in patients from a clinical analysis laboratory. 2. Material and Methods This study was approved by the Research Ethics Committee (COEPE) of Cesmac University Center, protocol number: 1.080.029. We conducted a retrospective descriptive study using a cross-sectional, quantitative design. A parasitological analysis of 1,277 stool samples was conducted using the spontaneous sedimentation technique (Hoffman, Pons, and Janer (HPJ)), to determine the presence of protozoan cysts. We examined two replicates (blades) per sample per individual. Data on age, gender, etiologic agent (protozoan) as well as results of the parasitological analysis were collected using a collection instrument. All data were recorded in logbooks maintained for our study, at the Parasitology Laboratory. Since we did not specifically distinguish between Entamoeba histolytica and Entamoeba dispar; these species are referred to as E. histolytica/E. dispar in this paper. Our objective was to evaluate the frequency of intestinal protozoa diagnosed in patients from a clinical analysis laboratory. We included all patient records from June to December 2015 and excluded those where patients had reported helminth infections. All data were entered into a spreadsheet, Microsoft Office Excel®, version 2013. We then conducted a descriptive analysis and reported the results as percentages. 3. Results and Discussion We examined 1,277 stool samples, of which 162 (12.69%) were positive for one or more protozoa. 38 (23.46%) cases were detected among children aged 0 to 10 years, 30 cases (18.51%) among teenagers aged 11 to 20 years, 23 cases (14.20%) among adults aged 21 to 30 years, 15 cases (9.26%) among adults aged 31 to 40 years, 20 cases (12.35%) among adults aged 41 to 50 years, and 25 cases (15.43%) among adults aged 60 years and above. Thus, we observed a high frequency of cases in children aged 0 to 11 years. Bioscience Journal | 2022 | vol. 38, e38001 | https://doi.org/10.14393/BJ-v38n0a2022-42370 3 SANTOS, T.L., et al. Our results indicated that infection occurred more frequently in females (91 cases (56.17%)), than in males (71 cases (43.83%)). Table 1 depicts the species distribution of intestinal protozoa detected in our samples. E. nana was the most prevalent (59.22%), followed by E. coli (23.45%). These percentages are similar to those reported by Melo et al. (2015). However, the number of cases that we detected was lower, than that reported by Menezes et al. (2013) and Seixas et al. (2011). This difference could be due to the diverse patient populations examined. Our results are similar to those reported by Ferreira et al. (2013), who observed a higher frequency of infections in women (65.4%) than in men (34.6%). More frequent infections in females can be attributed to the fact that, women are more exposed to environments that are conducive to transmission of infection. In addition, they also seek health services more often than men and are therefore more likely to be diagnosed (Menezes, 2013). Several studies have examined the occurrence of intestinal parasitic infections in various age groups. A high frequency of infections is observed in children aged 0 to 11 years. Our results corroborate this observation (Almeida-Filho et al. 2017; Bezerra et al. 2019; Rocha et al. 2019; Lima et al. 2020). Zaratin et al. (2018) also report similar results, and further demonstrate that intestinal parasitosis is more frequent among children in whom personal health and hygiene habits are not well developed. Table 1. Species Distribution of various intestinal protozoa, detected in patients from a clinical analysis laboratory in Maceió (AL), Brazil, between July and December 2015. Protozoan Species Absolute Frequency Relative Frequency (%) Endolimax nana 96 59.26 Entamoeba coli 38 23.46 Giardia lamblia 18 11.11 Entamoeba histolytica/Entamoeba díspar 10 6.17 Total 162 100 According to Oliveira et al. (2015), the frequency of intestinal parasitic infections decreases with increasing age. This agrees with our results, where we observed a higher number of infections in children compared to other age groups. Punsawad et al. (2017) attribute this decrease to acquired immunity against intestinal parasites, and modifications in habits and hygiene practices. Further, we also observed associations between various parasites. Monoparasitism was detected in 93.83% (152) of cases, biparasitism was detected in 4.55% (3) of cases, and polyparasitism was detected in 1.62% (1) of cases (Table 2). Table 2. Parasitic associations of intestinal protozoa detected in patients from a clinical analysis laboratory in Maceió (AL), Brazil, between July and December 2015. Protozoan Species Absolute Frequency Relative frequency (%) E. coli + E. nana 02 2.93 G. lamblia + I. buetschlii 01 1.62 E. coli + E. nana + E. histolytica + G. lamblia 01 1.62 Total 04 6.17 It should be noted that, E. nana and E. coli were the two most common species detected. However, these species do not pose any health risks. Rather, they are indicators of transmission by the fecal-oral route, and thus denote the individual’s susceptibility to acquired pathogens (Poulsen and Stensvold, 2016). Our observations are similar to those reported by Dudlová et al. (2018). The frequency of the pathogenic protozoa, E. histolytica/E. dispar was observed to be 6.17%, which is different from the results of other studies (Costa et al. 2018). Despite the implementation of regulations and increasingly stringent water treatment measures, the incidence of waterborne intestinal parasitic infections, especially those caused by protozoa, has risen in the last 25 years, thus becoming a major public health problem (Hafiz et al. 2015). Bioscience Journal | 2022 | vol. 38, e38001 | https://doi.org/10.14393/BJ-v38n0a2022-42370 4 Frequency of intestinal protozoan infections diagnosed in patients from a clinical analysis laboratory Our results are consistent with the findings by Lima et al. (2020) on the prevalence of intestinal parasites in patients from the Clinical Analysis Laboratory of University Hospital in Santa Cruz, RN. They detected monoparasitism in 75.5% of samples, and polyparasitism in 24.5% of samples. Further, Almeida Filho et al. (2017) reported a prevalence of parasitic diseases in the metropolitan region of Fortaleza, Ceará; polyparasitism was detected in 0.47% of individuals. The prevalence of parasitic infections caused by various etiological agents is primarily associated with inadequate sanitation facilities (Liao et al. 2017; Humphries et al. 2017). Our results corroborate the observation that, frequency of parasitic infections varies with geographical location, even within the same municipality (Rocha et al. 2010; Rocha et al. 2011; Silva et al. 2018; Almeida Filho et al. 2018; Lima et al. 2020). The frequency of intestinal parasites observed in our study depicts a low socioeconomic status of the study population. In addition, it denotes a lack of education among children, as indicated by the highest frequency of infections in this age group (Zaratin et al. 2018). Inadequate personal hygiene practices are possibly the primary factor contributing to the transmission of intestinal parasites (Dudlová et al. 2018; Costa et al. 2018). 4. Conclusions We detected a high frequency of intestinal protozoan infections, with a predominance of cases in women. Infections caused by E. nana were the most prevalent, followed by E. coli. The highest number of cases was observed in the age group between 0 to 20 years. Our results emphasize the need for implementation of preventive measures against intestinal parasitosis. The high frequency of cases observed, suggests a need to develop public health measures promoting good hygiene practices. In addition, educational programs aimed at lowering the incidence and impact of intestinal parasitosis, should primarily be targeted towards needy populations. Authors' Contributions: SANTOS, T.L.: conception and design, acquisition of data, analysis and interpretation of data, drafting the article; CARVALHO NETO, A.P.M.C.: conception and design, acquisition of data, analysis and interpretation of data, drafting the article; FERREIRA, J.R.S.: conception and design, acquisition of data, analysis and interpretation of data, drafting the article; AZEVEDO, P.V.M.: conception and design, acquisition of data, analysis and interpretation of data, drafting the article; SILVA, K.W.L.: conception and design, acquisition of data, analysis and interpretation of data, drafting the article; NASCIMENTO, C.M.A.: acquisition of data, analysis and interpretation of data; CALHEIROS, C.M.L.: acquisition of data, analysis and interpretation of data; WANDERLEY, F.S.: acquisition of data, analysis and interpretation of data; CAVALCANTI, M.G.S.: analysis and interpretation of data, drafting the article; ROCHA, M.A.N.: acquisition of data, drafting the article; MATOS -ROCHA, T.J.: analysis and interpretation of data, drafting the article. All authors have read and approved the final version of the manuscript. Conflicts of Interest: The authors declare no conflicts of interest. Ethics Approval: Approved by Research Ethics Committee of Cesmac University Center. Number: 1.080.029. Acknowledgments: The authors would like to thank the funding for the realization of this study provided by the Brazilian agency PIP/UNCISAL (Programa de Incentivo à Pesquisa da Universidade Estadual de Ciências da Saúde de Alagoas - Brasil). References ALMEIDA FILHO, M.A., et al. Prevalência de enteroparasitas na região metropolitana de Fortaleza, Ceará. Acta Biomedica Brasiliensia. 2017, 8(2), 91-100. https://doi.org/10.18571/acbm.143 ANSELMI, M., et al. Mass Administration of Ivermectin for the Elimination of Onchocerciasis Significantly Reduced and Maintained Low the Prevalence of Strongyloides stercoralis in Esmeraldas, Ecuador. 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Received: 16 May 2019 | Accepted: 7 June 2021 | Published: 16 February 2022 This is an Open Access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. https://doi.org/10.1016/j.actatropica.2013.12.010 https://doi.org/10.4269/ajtmh.16-0682 https://doi.org/10.1016/j.actatropica.2017.08.021 https://doi.org/10.13037/ras.vol18n63.6218 http://repositorio.unifap.br/bitstream/123456789/191/1/Dissertacao_CaracterizacaoEpidemiologicaEnteroparasitoses.pdf http://dx.doi.org/10.1371/journal.pone.0137327 http://dx.doi.org/10.4103/tp.TP_27_17 http://dx.doi.org/10.4103/2229-5070.175077 https://doi.org/10.1186/1756-3305-7-37 http://dx.doi.org/10.1186/s12889-017-4486-2 http://dx.doi.org/10.1016/j.eimc.2016.02.002 https://doi.org/10.5216/ref.v7i3.12893 https://doi.org/10.5216/rpt.v40i4.16762 https://doi.org/10.17648/diversitas-journal-v3i2.628 http://dx.doi.org/10.1007/s12639-016-0814-1 http://dx.doi.org/10.1016/S1473-3099(15)00268-6