March 2007 Vol 7 Isuue 1 FINAL without suicide .indd SULTAN QABOOS UNIVERSITY MEDICAL JOURNAL APRIL 2007 VOL 7, NO. 1 SULTAN QABOOS UNIVERSITY© 1Parasitology Department, Faculty of Medicine, Sebha University, Sebha, Libya 2Parasitology Department, Faculty of Medicine, Al-Fateh University, Tripoli, Libya. *To whom correspondence should be addressed. Email: alfellani@yahoo.co.uk Prevalence and Clinical Features of Blastocystis hominis Infection among Patients in Sebha, Libya *Mohammed A Al-Fellani1, Abdul H Khan1, Rugaia M Al-Gazoui1, Mabrouk K Zaid2, Mahmoud A Al- Ferjani2 ABSTRACT Objective: To determine the prevalence and seasonal variation, and to assess the clinical manifestations and treatment of blastocystosis in Libyan patients. Methods: Three thousand six hundred and forty five stool samples were screened for Blastocystis hominis using normal saline and iodine solution preparations. The clinical features of 08 patients were described, in whom B. hominis was the only parasite isolated. Fifty symptomatic patients were treated with 500 mg metronidazole daily for 7 days and their stools were re-investigated for B. hominis. Results: B. hominis was found in 969 (26.58 %) of 3645 stool specimens examined. The infection of B. hominis was significantly more (p < 0.05) in summer than in winter over a three year period. In a prospective study of 08 patients, the most common symptoms with stools positive only for B. hominis were diarrhoea (84.94 %), abdominal pain (66.66 %), flatulence (7.20 %) and vomiting (6.2 %). High concentration of B. hominis cells were found more in symptomatic patients than asymptomatic ones (9.20 cells per 40 X field versus 4.06 respectively) with statistically significant differences (p < 0.00). Patients with B. hominis responded to metronidazole and were fully cured after 7 days. Conclusion: The occurrence of B. hominis infections in outpatients are probably related to weather conditions, with the suggestion that the hot, dry weather of the Sebha region favors the development and transmission of this organism. B. hominis infections might have a role in some pathological conditions, resulting in gastrointestinal symptoms. Key words: Blastocystis, Seasonal variation, Culture, Diarrhoea. عند السريرية وصفاتها رِيَّة البَشَ يَّةُ الكيسِ ةُ مَ املُتَبَرْعِ عدوى انتشار (ليبيا) سبها في املرضى على الفرجانى ومحمود خليفة زايد مبروك اجلازوى، محمد رقية عبد احلفيظ خان، الفالني، محمد عبد السالم للمرضى والعالجية السريرية احلالة تقييم وكذلك فيها، املوسمي االختالف رِيَّة ومعرفة البَشَ ــيَّةُ الكيسِ ةُ مَ ُتَبَرْعِ امل ــار انتش امللخص: الهدف: حتديد ومحلول نظامي ملحي محلول باستعمال رِيَّة البَشَ يَّةُ الكيسِ ةُ مَ ُتَبَرْعِ حالة امل 3645 لتقصي من براز الطريقة: أخذنا عينات بها. املصابني الليبيني بعقار أعراضا لديهم كانت ممكن مريضا ــني خمس عولج فقط. ــرِيَّة البَشَ ــيَّةُ الكيسِ ةُ مَ ُتَبَرْعِ بامل مصابا 108 مريضا ــريرية ل احلالة الس وصف مت اليود. (26.58%) 969 في رِيَّة البَشَ يَّةُ الكيسِ ةُ مَ ُتَبَرْعِ امل النتائج: وجدت مرة أخرى. فحص البراز أعيد أيام، وبعدها ملدة سبعة (1500 ملجم) امليترونيدازول P=0.05) معتد إحصائي بفارق الثالث ــنوات الس في ــتاء الش في منه الصيف في حدوثا أكثر العدوى كانت .3645 البراز البالغة مجموع عينات من ،(66.66%) البطن ألم ،(84.94%) ــهال اإلس هي املوجب للبراز الفحص مع ــيوعا ش كانت األعراض األكثر 108 مريضا، ــبقة ل مس ــة في دراس .( (9.20 خلية غيرهم عن أعراضا يظهرون الذين املرضى عند أكثر رِيَّة البَشَ يَّةُ الكيسِ ةُ مَ ُتَبَرْعِ امل خاليا عدد كان .(16.12%) والتقيؤ (17.20%) الغازات بعقار ــرِيَّة البَشَ ةُ ــيَّ الكيسِ ةُ مَ ُتَبَرْعِ بامل املصابون املرضى ــفي ش . (P<0.001)معتد إحصائي وبفرق 4.06 لآلخرين)، مقابل 40 مرة التكبير مجال في أن حيث باملناخ، عالقة لها اخلارجية العيادة مراجعي عند رِيَّة يَّةُ البَشَ الكيسِ ةُ مَ ُتَبَرْعِ العدوى بامل تكون : رمبا اسبوع. اخلالصة فترة امليترونيدازول خالل التي املرضية احلاالت دورا في بعض بها تلعب العدوى رمبا والتي ــرِيَّة، البَشَ يَّةُ الكيسِ ةُ مَ ُتَبَرْعِ وانتقال امل تكاثر على ــاعد واجلاف قد يس احلار ــبها س مناخ هضمية. أعراضا تسبب الزرع. اإلسهال، الفصلية، التغيرات يَّة، الكيسِ ةُ مَ ُتَبَرْعِ الكلمات: امل مفتاح C L I N I C A L & B A S I C R E S E A R C H M O H A M M E D A A L - F E L L A N I , A B D U L H K H A N , R U G A I A M A L - G A Z O U I , M A B R O U K K Z A I D A N D M A H M O U D A A L - F E R J A N I 36 INFECTION BY BLASTOCYSTIS HOMINIS OCCURS all over the world, but is commonly found in de-veloping countries.¹’² Practicing physicians and gastroenterologists usually have low awareness of the association of B. hominis with human disease. These infections are overlooked in clinical laboratories. The Centre for Disease Control and Prevention also con- sidered it to be a pathogenic protozoan.³ B. hominis is now increasingly recognized as a possible cause of gastrointestinal disorders.4-7 A subgroup of B. hominis could possibly be pathogenic in some patients.8 The specific pathogenic potential of B. hominis has not been defined.9-12 The results of a recent study in Sebha, Libya, re- vealed that B. hominis was the most frequent isolate in all stool specimens submitted for analysis,13 but the clinical significance of B. hominis infection in the Lib- yan population has not been documented so far. In the present study, the aim was to investigate the prevalence of B. hominis among patients attending the Central Laboratory in Sebha, Libya and to describe the clinical presentations of patients parasitized only with B. hominis infection in Libyan communities. M E T H O D S This prospective study was performed in Sebha city, Fezzan Province, South-Western Libya. This region is characterized by a hot and dry climate. It is an arid and desert area with a population of over one hundred thirty thousand. Most people work in agriculture. A total of 3,645 stool samples were collected (from the beginning of January to the end of December 2005) from outpatients attending the Central Laboratory in Sebha, Libya, for routine examination of intestinal parasites. Soon after the collection of stool specimens, two faecal smears were prepared (normal saline and Lugol’s iodine) from each sample. These preparations were examined under both a low power (10 X) and a high power (40 X) of microscope to detect possible B. hominis. The seasonal prevalence of B. hominis was record- ed among 8,089 patients, who attended the Central Laboratory in Sebha, over a 3 year period from Janu- ary 2003 to December 2005. A prospective study on 108 patients parasitized exclusively with B. hominis was performed. Clinical information on patients with stools which tested posi- tive for B. hominis was obtained by sending a survey questionnaire to practicing physicians at the Al-Jadeed clinic in Sebha, Libya. The numbers of B. hominis cells in faecal materials were counted with a 40 X field mi- croscope. Ninety three patients harboured only B. hominis and presented with gastrointestinal symptoms (diar- rhoea with or without abdominal pain and flatulence or vomiting) were treated for seven days with metroni- dazole 500 mg three times per day for 7 days. Only fifty patients returned back for a follow up examination. Stool samples from these patients were re-examined for B. hominis after completion of the therapy. The positive rate of B.hominis was expressed as a percentage (number, sex, seasonal variation, diarrhoea etc) and statistical analysis was carried out using the independent sample t-test. P-values of < 0.05 and 0.001 were considered statistically significant. R E S U L T S The prevalence of B. hominis was found to be 26.58 % among outpatients at the Central Laboratory in Sebha. Of the 3,645 patients examined, 1,925 (52.81 %) were males and 1,720 (47.18 %) were females. A total of 558 (28.98 %) males and 411 (23.89 %) females were har- bouring B. hominis. The highest positivity (10.28 %) rate was found in the 21 to 40 age group. The seasonal variation of B. hominis among pa- tients attending the Central Laboratory in Sebha is presented in Table 1. The prevalence of B. hominis was found to be significantly more (p<0.05) in summer Year Summer season* Winter season** Total investigated No. No. Positive No. No. Positive No. No. Positive*** 2003 2572 458 (17.80) 1855 279 (15.04) 4427 737 (16.64) 2004 2264 497 (21.95) 1398 267 (19.09) 3662 764 (20.86) 2005 2336 640 (27.39) 1309 329 (25.13) 3645 969 (26.58) Figures in parentheses indicate percentages. * April to October. ** November to March. *** p < 0.05 versus comparison with summer and winter season. Table 1 : Seasonal variation of B. hominis among patients attending the Central Laboratory in Sebha 37 P R E VA L E N C E A N D C L I N I C A L F E AT U R E S O F B L A S T O C Y S T I S H O M I N I S I N F E C T I O N A M O N G PAT I E N T S I N S E B H A , L I B YA than in winter. The clinical presentations of 93 patients parasitized exclusively with B. hominis are shown in Table 2. The most frequent manifestation was diarrhoea (84.94%). Sixty-four (68.81%) patients had two or more gas- trointestinal complaints. Twenty-nine patients (31.18 %) had only one clinical feature (25 had diarrhoea and 4 had cramping abdominal pain). Forty-nine patients (52.68 %) had two gastrointestinal complaints (33 had diarrhoea with cramping abdominal pain, 6 had diar- rhoea with vomiting, 2 had vomiting with cramping abdominal pain and 8 had cramping abdominal pain with flatulence). Fifteen patients (16.12 %) had three clinical symptoms of blastocystosis (7 had diarrhoea with cramping abdominal pain and vomiting, 8 had diarrhoea with cramping abdominal pain and flatu- lence). The intensity of B. hominis among symptomatic and asymptomatic individuals is presented in Table 3. The mean number of B. hominis was significantly higher (p<0.001) in symptomatic patients than in asympto- matic individuals (9.20 ± 2.41 organisms per 40 X field, versus 4.06 ± 1.86 respectively). Two infected persons, in whom B. hominis cells were found 10 and 12 per 40 X field, were entirely asymptomatic. B. hominis were not found in stools from patients upon the completion of the 7 day therapeutic course of metronidazole. All fifty patients showed clinical improvement and were fully cured using 1500 mg of metronidazole daily for 7 days. D I S C U S S I O N Physicians usually have low awareness that B. hominis is a cause of human disease. The number of infections appears to be high in most populations, however, the frequency is grossly underestimated. Asymptomatic shedding of B. hominis provides an appropriate en- vironment for its transmission to other subjects. Re- cently B. hominis has been considered as potential pathogen. 5-7 Infections of B. hominis may be an important pu- bic health problem in Libyan communities. 30-32 So far, only one study has been carried out on the prevalence of B. hominis among patients attending the Central Laboratory in Sebha, Libya.13 This study was carried out to investigate the prevalence, seasonal variation and the association between the presence of B.hominis and gastrointestinal symptoms among patients. The results of this study show that B. hominis was detected in 26.58 % of stool specimens examined. Very similar prevalence have been described in other parts of the world: 25% in Jordan,3 32% in Pakistan,6 18% in Bethesda,14 31% in Egypt,20 25.78% in Venezuela,24 26.5% in Brazil29 and 22.9% in Argentina33 [Table 4]. However, higher prevalence of B. hominis has been reported in other countries of the world: 36% in Tanzania,23 40.7% in Philippines,25 36.9% in Thailand,26 and 46.9% in Venezuela.34 In the present study, the prevalence of B. hominis was higher than previously reported among the same population. This may be due to improvement in detection of B. hominis infec- tion in clinical laboratories, but infections with this or- ganism may have also increased in the population. In the Libyan Arab Jamahiriya, the rapid socio-economic development, agriculture practices and the enormous increase in the number of foreign workers from neigh- bouring countries may have lead to a substantial in- crease of intestinal parasites in the country. Prior re- search has shown that immigrants and refugees from Clinical symptoms No. of cases Diarrhoea 79 (84.94) Cramping abdominal pain 62 (66.66) Flatulence 16 (17.20) Vomiting / Nausea 15 (16.12) Parasitized exclusively by B. hominis. Figures in parentheses indicate percentages. Table 2: Clinical Manifestations of 93 Symptom- atic Patients Table 3: Intensity of B. hominis Infection among Blastocystosis Patients. Category No. of cases and (%) Intensity of B. hominis No. of organisms Mean of No. ± SD No. of organisms Mean of No. ± SD Symptoms 93 (86.11) Positive for B. hominis with gastrointestinal symptoms More than 7 9.20±2.41** (8 to 30)* Symptoms 15 (13.88) Positive for B. hominis without trointestinalsymptoms Less than 5 4.06±1.86 (2 to 12)* * Range of No. of B. hominis cells per 40 X field. ** p < 0.001 versus comparison with number of B. hominis cells among asymptomatic individuals. M O H A M M E D A A L - F E L L A N I , A B D U L H K H A N , R U G A I A M A L - G A Z O U I , M A B R O U K K Z A I D A N D M A H M O U D A A L - F E R J A N I 38 developing countries have a higher incidence of B. hominis. In the present study, males were more infected (28.98%) with B. hominis than females (23.89%). The difference was significant (p<0.05). Several studies have reported significantly higher prevalence in male than female patients.2, 3, 12 The parasitological examination of faecal samples revealed that the incidence of B. hominis is widespread throughout the year with a particular peak in the sum- mer season. The high incidence of B. hominis in the Sebha region may be due to the dry climatic condi- tions that favour the survival and transmission of this organism in the population throughout the year. This is in contrary to other parts of the world, where in- fections of B. hominis are commonest during the pre- monsoonal months, spring and winter seasons.16, 20, 27 The most prominent gastrointestinal symptoms in 93 patients parasitized exclusively by B. hominis were diarrhoea (84.94%), cramping abdominal pain (66.66%) and nonspecific gastrointestinal symptoms such as flatulence (17.20%) and nausea or vomit- ing (16.12%). These symptoms were similar to the one reported previously in patients infected with B. hominis. 2-8, 20 In the present study, the number of B. hominis was significantly higher (p < 0.001) in the stools of sympto- matic patients than in asymptomatic individuals (more than seven cells with mean number 9.20 ± 2.41 versus less than five with mean number 4.06 ± 1.86). Several studies have reported detecting more than five cells of B. hominis per 40 X field in stool samples from symptomatic patients.3, 7, 20, 35 In addition five or more B. hominis cells per oil immersion field (100 X) have been detected in symptomatic patients.22,36-38 The mean numbers of B. hominis cells in the stools of symptomatic patients were significantly higher than asymptomatic patients.5, 7 Several studies reported severe symptoms in pa- tients with high numbers of B. hominis,9, 20 however, this correlation was not found in others.21, 22, 40 In the present study, among asymptomatic sub- jects (except two cases) the number of B. hominis cells found was less than five per 40 X field. Similarly less Reference Country / Locality % of B. hominis Wang et al2 Community population in China 3.7 Nimri3 Preschool children in Jordan 25.0 Yakoob et al6 Outpatients in Pakistan 32.0 Al-Fellani et al13 Outpatients in Libya 18.5 Zierdt14 Community population in Bethesda 18.0 Garcia et al.15 Outpatients in Los Angeles 12.0 Babock et al.16 Population in Nepal 10.0 Markell and Udkow17 Outpatients in San Francisco 12.0 Sheehan et al.18 Outpatients in New York 11.0 Kain et al.19 Outpatients Vancouver 13.0 El Masry et al.20 Outpatients in Egypt 31.0 Doyle et al.21 Outpatients in Canada 3.2 Martin-Sanchez et al.22 Primary school children in Spain 19.4 Gomez Morales et al.23 Outpatients in Tanzania 36.0 Requena et al.24 Food handlers in Venezuela 25.8 Eleonor et al.25 Children in Philippines 40.7 Leelayoova et al.26 Army personal in Thailand 36.9 Suresh and Smith27 Outpatients in United Kingdom 3.9 Khan and Khalife28 Food handlers in Saudi Arabia 8.5 Nascimento and Moitinho29 Community population in Brazil 26.5 Present study Outpatients in Libya 26.58 Table 4: Prevalence of B. hominis in various countries/states of the world. 39 P R E VA L E N C E A N D C L I N I C A L F E AT U R E S O F B L A S T O C Y S T I S H O M I N I S I N F E C T I O N A M O N G PAT I E N T S I N S E B H A , L I B YA than five organisms (fewer than three) per 40 X mi- croscopic fields among stool samples of apparently healthy subjects have been reported.3, 24 Large num- bers of B. hominis were also observed in faeces of some asymptomatic individuals.12, 22, 41 In this prospective study, the physicians of Health Centre Al-Jadeed in Sebha successfully treated fifty patients infected with B. hominis with metronidazole 500 mg three times per day for 7 days. In all these patients, no other parasites were demonstrated in the faecal specimens. All patients responded to the therapy and symptoms disappeared after 7 to 10 days. Moreover, B. hominis was not detected in the stools of patients after 7 days. This suggests that the gastrointestinal symptoms in all these patients (positive only for B. hominis) are probably due to B. hominis infection. Metronidazole has been suggested as the first line chemotherapeutic agent for treatment of B. hominis infection.42-44 How- ever, some authors reported that metronidazole did not eradicate the B. hominis completely and was effec- tive only in some individuals.6, 45, 46 In conclusion, we report that B.hominis is a com- mon intestinal protozoa infection in Sebha and with higher prevelance in warm and hot seasons of the year. In patients with blastocystosis, gastrointestinal symp- toms are more likely to be associated with intensity of B. hominis. 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