Abstract
Background:
Blastocystis hominis is an enteric protozoan in humans and animals. This survey aimed to assess the knowledge and practice of physicians about B. hominis.Methods:
This study was performed on physicians working in Ahvaz County, using a convenience sampling method from January to June 2020. Data were collected through face-to-face interviews and an electronic questionnaire. Descriptive statistics, including frequencies and percentages, were calculated for all variables. P-values < 0.05 were considered significant.Results:
Our results showed that of the 352 physicians, 64.2% and 58.0% knew that B. hominis might cause abdominal pain and diarrhea, respectively, but their knowledge was poor about the possibility of extraintestinal clinical symptoms such as urticaria. Regarding the transmission route, 91.8% agreed that the fecal-oral route is the main mode of B. hominis transmission, but only 17.9% were aware of the role of host animals in its transmission. Furthermore, the physicians had poor knowledge of the need to treat symptomatic patients and resistance to metronidazole in some cases. More than two-thirds of the physicians (68%) had good practice treating infected immunocompromised patients but had poor practice treating symptomatic patients.Conclusions:
This study emphasizes improving physicians’ knowledge of pathogenicity, clinical symptoms, and treating B. hominis. Since B. hominis is a common protozoan with pathogenic potential, we recommend training sessions for physicians to inform them of new findings about B. hominis.Keywords
1. Background
Blastocystis hominis is a common enteric protozoan in humans and animals (1, 2). This intestinal protozoan has a worldwide distribution with a prevalence of more than 1 billion people worldwide (3). Blastocystis hominis is more common in developing countries (4). Since this eukaryotic microorganism is reported in asymptomatic and symptomatic individuals, its pathogenicity remains controversial (3). In symptomatic cases, B. hominis has been linked to clinical manifestations, such as diarrhea, abdominal pain, irritable bowel syndrome (IBS), irritable bowel disease (IBD), constipation, flatulence, and urticaria (5-7).
Molecular studies on the small subunit of the ribosomal RNA (SSU rRNA) gene led to identifying at least 17 subtypes (ST1–ST17). ST1–ST9 and ST12 have been reported in humans and animals (2, 8). Therefore, these subtypes may be zoonotic and transmitted by contact with infected animals and/or via contaminated water with B. hominis cysts through the fecal-oral route (8). Direct smear examination and xenic culture are typical methods for diagnosing B. hominis. Since culture is a time-consuming technique, molecular methods like real-time quantitative PCR (qPCR) assays have been proposed to detect B. hominis in stool samples (9). Blastocystis hominis has vacuolar, granular, multivacuolar, avacuolar, amoeboid, and cyst forms (10). The small cyst stage, the transmitter form, may be difficult to diagnose by stool examination (1). One of the important issues with B. hominis is whether or not to treat infected individuals. The controversial pathogenicity of the protozoan has made treatment equivocal (11).
In Iran, in a systematic review and meta-analysis study, a total prevalence of 3% was reported for B. hominis (12). In a study by Khademvatan et al. in 2018, intestinal parasites were assessed in stool samples from Ahvaz County, and Blastocystis was observed in 14.35% of the examined stool samples (13). In another study conducted in Ahvaz County on 618 human fecal samples, Blastocystis had a prevalence of 23.6%, and ST3 was the most commonly observed ST (14). Despite the controversial treatment, diagnosis, and pathogenicity of this common intestinal protozoan, no study has yet been conducted to assess the level of knowledge and practice of the Iranian medical community about this parasite.
2. Objectives
The present study evaluated the knowledge and practice of physicians in Ahvaz County to include, if necessary, new findings about B. hominis in retraining the medical community.
3. Methods
3.1. Study Design
This cross-sectional study was performed on physicians working in private and government hospitals in Ahvaz County using a convenience sampling method from January to June 2020. Ahvaz County, the capital of Khuzestan Province, with a population of about 1.3 million and 815 km2, is located in southwestern Iran. The county has 19 hospitals.
3.2. Sample Size
Due to the lack of appropriate estimates for the desired values in the target population and to maximize the sample size with P = 0.5 and d = 0.05, the sample size was calculated at 375 physicians. Twenty-three physicians who had answered only one or two questions were excluded from the study. The number of participants from each hospital was proportional to the number of physicians in that hospital.
3.3. Inclusion Criterion
The inclusion criterion was physicians with a work experience of more than two years and being residents of Ahvaz County.
3.4. Questionnaire
The questionnaire's first section consisted of gender, age, occupation, educational status, and duration of work experience. The second section of the questionnaire included eight knowledge-based and four practice-based questions. Content validity was assessed using an evaluation of the items by ten experts, and the validity results were acceptable. Besides, test-retest reliability was assessed by answering the items by 30 participants twice over three weeks. The calculated correlation coefficient was 0.76, which indicates acceptable reliability. The survey data was collected through a face-to-face interview at the beginning of the study and was continued with an electronic questionnaire due to the outbreak of Coronavirus disease 2019 (COVID-19).
3.5. Data Analysis
Statistical analyses were conducted using SPSS 16 software (SPSS Inc., Chicago, IL, USA). Descriptive statistics, including frequencies and percentages, were calculated for all variables. P-values < 0.05 were considered significant.
3.6. Ethics Approval and Consent to Participate
The protocol of the present study was reviewed and approved by the Ethics Committee of the Student Research Committee, Ahvaz Jundishapur University of Medical Sciences (IR.AJUMS.REC.1398.836). The methods were carried out in accordance with relevant guidelines and regulations.
4. Results
4.1. Socio-demographic Characteristics
Of the 352 physicians, 187 (53.1%) were male and 165 (46.9%) were female. The average age of the participants was 40.1 (SD: 8.3; range = 25 - 59 years old). The physicians included 158 (44.9%) general physicians, 72 (20.5%) internal medicine practitioners, 41 (11.6%) pediatricians, 17 (4.8%) gastroenterologists, 11 (3.1%) infectious disease specialists, and 53 (15.1%) other specialists. Regarding the responding method, 31.5% responded using face-to-face interviews, and 68.5% used an electronic questionnaire.
4.2. Physicians' Knowledge Regarding Blastocystis hominis
A high percentage of physicians (77.8%) knew that B. hominis is a parasite, but less than a third (29.5%) knew that B. hominis infection does not correlate with age. Regarding clinical symptoms, 64.2%, 58.0%, and 13.9% knew that B. hominis might cause abdominal pain, diarrhea, and urticaria, respectively. Approximately two-thirds (64.5%) of the study physicians knew that B. hominis colonize the human gut, but only 43.8% believed that B. hominis might be an emerging pathogen. Less than half of the physicians (36.4%) knew there was no correlation between B. hominis infections and occupation. Most physicians (91.8%) agreed that the fecal-oral route is the main mode of B. hominis transmission, and 63.4% believed that B. hominis had been linked to IBS. In addition, 64.2% knew there was no need to treat asymptomatic individuals (Table 1).
Knowledge of Blastocystis hominis Among Physicians (N = 352) Participating in This Study
| Question (Group) | Yes, No. (%) | No, No. (%) |
|---|---|---|
| What is your opinion about B. hominis? | ||
| It colonizes the gut | 227 (64.5) | 125 (35.5) |
| It is a non-pathogenic protist | 44 (12.5) | 308 (87.5) |
| All infected people are asymptomatic | 32 (9.1) | 320 (90.9) |
| It might be an emerging pathogen | 154 (43.8) | 198 (56.3) |
| Which occupation group is more likely to be infected with B. hominis? | ||
| Rancher | 127 (36.1) | 225 (63.9) |
| Food seller | 84 (23.9) | 268 (76.1) |
| Farmer | 50 (14.2) | 302 (85.8) |
| No correlation between occupation | 128 (36.4) | 224 (63.6) |
| What are the common modes of B. hominis transmission? | ||
| Fecal-oral | 323 (91.8) | 29 (8.2) |
| Blood transfusion | 3 (0.9) | 349 (99.1) |
| Congenital | 5 (1.4) | 347 (98.6) |
| Exposure to infected animals | 63 (17.9) | 289 (82.1) |
| Sexual | 9 (2.6) | 343 (97.4) |
| Airborne | 20 (5.7) | 332 (94.3) |
| Which disease may B. hominis be linked to? | ||
| Celiac | 61 (17.3) | 291 (82.7) |
| IBS | 223 (63.4) | 129 (36.6) |
| Ulcerative colitis | 68 (19.3) | 284 (80.7) |
| Asthma | 54 (15.3) | 298 (84.7) |
| What is true about B. hominis? | ||
| Asymptomatic individuals do not need to be treated | 226 (64.2) | 126 (35.8) |
| It may be a marker of gastrointestinal health | 22 (6.3) | 330 (93.8) |
| Symptomatic patients should be treated | 108 (30.7) | 244 (69.3) |
| In IBS patients, B. hominis may reduce gastrointestinal symptoms | 37 (10.5) | 315 (89.5) |
4.3. Physicians' Practice Regarding Blastocystis hominis
About 68% had a practice of treating infected immunocompromised patients, and 44.9% treated symptomatic patients. Among them, 64.5% reported that they prescribed metronidazole for treatment. In addition, 71.6% and 79.3% believed that B. hominis should be treated in symptomatic celiac and ulcerative colitis patients, respectively (Table 2).
Practice of Participating Physicians (N = 352) on Blastocystis hominis in This Study
| Question (Group) | Yes, No. (%) | No, No. (%) |
|---|---|---|
| Which group should be treated if B. hominis was the only organism reported in stool examination? | ||
| Immunocompromised patients | 239 (67.9) | 113 (32.1) |
| Symptomatic patients | 158 (44.9) | 194 (55.1) |
| Children | 51 (14.5) | 301 (85.5) |
| Pregnant women | 33 (9.4) | 319 (90.6) |
| If the patient needs treatment, which of the following medications do you prescribe? | ||
| Metronidazole | 227 (64.5) | 125 (35.5) |
| Iodoquinol | 48 (13.6) | 304 (86.4) |
| Azithromycin | 35 (9.9) | 317 (90.1) |
| Paromomycin | 61 (17.3) | 291 (82.7) |
| Do you think B. hominis should be treated in celiac patients? | ||
| Symptomatic patients should be treated | 252 (71.6) | 100 (28.4) |
| No need to treat symptomatic patients | 93 (26.4) | 259 (73.6) |
| Do you think B. hominis should be treated in ulcerative colitis patients? | ||
| Symptomatic patients should be treated | 279 (79.3) | 73 (20.7) |
| No need to treat symptomatic patients | 72 (20.5) | 280 (79.5) |
4.4. Correlation Between Work Experience and Knowledge and Practice of Physicians Toward Blastocystis hominis
Work experience had a significant effect on physicians' knowledge about B. hominis (r = 0.093; P = 0.008), but the association between work experiences and practices of physicians regarding B. hominis was not significant (r = 0.066; P = 0.061).
5. Discussion
The study aimed to evaluate the knowledge level of Ahvaz's physicians about B. hominis. Although it has been more than 100 years since Blastocystis was recognized, our results indicated still a percentage of physicians (16.2%) knew this protozoan as a fungus Blastocystis hominis was first classified as yeast, then as a protest, and as Stramenopiles (11). Due to insufficient knowledge about this parasite, the treatment of infected people is still controversial (11); however, knowing that B. hominis is a parasite can play an important role in adopting anti-parasitic treatment for patients with chronic symptoms. These findings are consistent with the study conducted by Berger et al. (2018) regarding Chagas disease, in which 97% of physicians knew it was a parasitic disease (15).
It was found that the majority of physicians were aware of the possibility of abdominal pain and diarrhea in some symptomatic patients, but they had little knowledge of urticaria in individuals infected with B. hominis. Some B. hominis STs, such as ST2 and ST3, may cause gastrointestinal and extraintestinal clinical manifestations such as chronic urticaria (16, 17). Lack of adequate knowledge of the skin manifestations caused by B. hominis may be due to the low reported urticaria cases in infected individuals (6, 18, 19). Another possible explanation is that B. hominis is less mentioned in educational programs and training courses in Iran.
This study found that around 92% of physicians knew the oral-fecal route as the main transmission route of B. hominis, but their knowledge of transmission through animal contact was low. This parasite is mainly transmitted through the oral-fecal route, but contact with animal hosts can also play a role in its transmission (11, 20). In agreement with our results, in a study conducted by Efuneshile et al., only 35% of healthcare professionals were aware that humans infected with Toxoplasma gondii could occur by consuming undercooked meat of infected animals (21). Adequate knowledge of parasites and their transmission routes, such as B. hominis, is important in preventing and controlling this enteric protozoan (22).
Although some evidence suggests that this protozoan is more common in the gut of healthy individuals, it is also recognized as a potential pathogen associated with IBS (20). IBS, a common gastrointestinal disorder with a worldwide distribution of 11.2%, has multiple etiologies. The pathogenesis of the disease is not fully understood, but it is believed that several factors, such as host-related factors, psychological state, and pathogens (bacterial, virus, parasites), are involved in increasing the risk of the development of IBS (23). Approximately 64% of physicians believe that B. hominis might be linked to IBS. It seems that being aware of a likely association between B. hominis and IBS can affect the treatment of the disease. A recent study conducted on Indonesian adolescents suggested Blastocystis ST1 as a pathogenic subtype of the IBS-D type (24).
In the present study, 64.2% of physicians believed that there is no need for treatment in the absence of clinical symptoms, but the noteworthy point is that only 30.7% of the physicians agreed to treat symptomatic patients. On the other hand, physicians' practice of treating symptomatic patients was also poor. Insufficient knowledge of the physicians about the pathogenicity of this parasite could be the reason for the poor practice of doctors in treating symptomatic patients.
In the present study, 64.5% of physicians recommended metronidazole as a first-line treatment option for B. hominis. Metronidazole is the most frequently recommended drug for B. hominis infection (11); however, resistance to metronidazole has been reported in various studies (11, 25, 26). For this reason, the necessity of metronidazole reassessment is recommended (26).
We found a significant correlation between years of experience and physicians' knowledge of B. hominis.
This study had limitations. First, due to the COVID-19 pandemic, we could not assess the knowledge and practice of all physicians about Blastocystis using a face-to-face questionnaire. The second limitation was that the grouping of physicians in terms of the specialty did not have a normal distribution.
5.1. Conclusions
This study showed that physicians had adequate knowledge about the parasitic nature of B. hominis, its most common route of transmission, as well as some of the common clinical symptoms caused by it, such as abdominal pain and diarrhea; however, their knowledge was poor about the role of host animals in its transmission, the need to treat symptomatic patients, the possibility of extraintestinal clinical symptoms such as urticaria, and resistance to metronidazole in some cases. Furthermore, the obtained results indicated that physicians' practices in treating symptomatic patients were also poor. This emphasizes the need to improve physicians' knowledge of the pathogenicity and treatment of B. hominis. Since B. hominis is a common protozoan with pathogenic potential, we recommend training sessions for physicians to inform them of new findings about B. hominis.
Acknowledgements
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