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Home , Dientamoebiasis, Giardiasis

ORIGINAL ARTICLE

Dientamoeba fragilis, a neglected cause of , successfully treated with N. Girginkardes¸ler1,S¸. Cos¸kun2,I˙.Cu¨neyt Balcıog˘lu1, P. Ertan2 and U¨.Z.Ok1

1Department of and 2Department of Pediatrics, Faculty of Medicine, Celal Bayar University, Manisa, Turkey

Objective To evaluate the pathogenicity of by comparing it with lamblia and to investigate the effect of a single dose of secnidazole in dienta- moebiasis. Methods Stool samples of 400 patients, admitted to the Department of Parasitology, Celal Bayar University, were examined by direct wet mount, formalin–ethyl acetate concen- tration and trichrome staining methods on three consecutive days. All cases positive for D. fragilis were treated with a single dose of secnidazole, 30 mg/kg for children, and 2 g for adults. On the seventh and fourteenth days, at the end of the treatment, stool samples were examined by the same methods, and clinical symptoms were again evaluated. Results D. fragilis and G. lamblia were detected in 35 (8.8%) and 34 (8.5%) cases, respectively. The most frequent symptoms were found to be and diarrhea in both infections. D. fragilis was eradicated in 34 (97.1%) patients with a single dose of secnidazole, but a second dose was necessary in one patient. Clinical symptoms disappeared in 27 (77.1%) and decreased in eight (22.9%) cases, after eradication. Conclusions These data suggested that D. fragilis is as prevalent and pathogenic as G. lamblia, and secnidazole seems to be highly effective in achieving parasitologic and clinical cure. To our knowledge, this is the first report of secnidazole being used in the treatment of . Keywords Dientamoeba fragilis, dientamoebiasis, treatment, secnidazole, epidemiology Accepted 8 March 2002 Clin Microbiol Infect 2003; 9: 110–113

, amebiasis and bacterial vaginosis INTRODUCTION [5,6]. The pathogenicity of Dientamoeba fragilis has been The objective of this study was to evaluate the debated for many years. Today, clinical symptoms frequency and the pathogenicity of D. fragilis by such as abdominal pain, diarrhea, anorexia, nau- comparing it with Giardia lamblia, a better-known sea, vomiting and flatulence, which usually dis- parasite. The effect of a single dose of secnidazole appear with the elimination of the parasite, are on D. fragilis was also investigated. reported to be associated with D. fragilis [1–4]. Secnidazole, a 5-, has a long half- MATERIALS AND METHODS life (approximately 17–29 h), and therefore has been used as single-dose therapy in , Stool samples of 400 patients admitted to the Department of Parasitology, Celal Bayar Univer- sity, were investigated for intestinal parasites three Corresponding author and reprint requests: N. Girginkar- times on consecutive days. Only fresh stool speci- des¸ler, Posta Kutusu 75, Manisa, Turkey Tel: þ90 232 421 4346 mens (within 30 min of passage) were accepted, Fax: þ90 236 237 6449 and were immediately fixed in both Schaudinn’s E-mail: [email protected] fixative and 10% formalin solution. All samples

ß 2003 Copyright by the European Society of Clinical Microbiology and Infectious Diseases Girginkardes¸ler et al Dientamoeba fragilis treated with secnidazole 111 were examined by direct wet smear, trichrome Table 1 Clinical symptoms in cases with only D. fragilis, staining (Wheatley modification), and formalin– only G. lamblia, and no pathogenic parasite ethyl acetate concentration procedures, as pre- Only Only No pathogenic viously described [7]. D. fragilis G. lamblia parasite A questionnaire was completed for each case, (n ¼ 32) (n ¼ 30) (n ¼ 326) concerning clinical symptoms (duration and sev- Symptoms n (%) n (%) n (%) erity, if any). Stool samples were examined macro- Abdominal pain 26 (81.3) 21 (70.0) 63 (19.3) scopically. At least three soft or liquid stools per Diarrhea 23 (71.9) 23 (76.7) 37 (11.3) day are considered to constitute diarrhea, and one Anorexia 5 (15.6) 2 (6.7) 34 (10.4) formed stool a day is regarded as disappearance 3 (9.4) 3 (10.0) 30 (9.2) Nausea 2 (6.3) 2 (6.7) 20 (6.1) of this symptom. Thirty-two cases with only D. 1 (3.1) 2 (6.7) 16 (4.9) fragilis and three patients with both D. fragilis and Vomiting 1 (3.1) 1 (3.3) 16 (4.9) G. lamblia infections were treated with a single dose of secnidazole after dinner, 2 g for adults and 30 mg/kg for children 3–15 years of age. This smear and/or formalin–ethyl acetate concentra- treatment was ineffective in only one adult patient, tion methods were found to be effective in detect- and the same dose of secnidazole was repeated in ing 33 of 34 cases positive for G. lamblia. Of the 35 this case. On the seventh and fourteenth days, at cases positive for D. fragilis, 30 were detected in the the end of the treatment, stool samples were exam- first, three in the second, and two in the third stool ined by the same methods, and clinical symptoms examination. were again evaluated; patients did not receive any The most frequent symptoms were found to be other drugs for one week before and two weeks abdominal pain (81.3%) and diarrhea (71.9%) in after the secnidazole treatment. patients with only dientamoebiasis. These two Adult patients and parents of the children were symptoms were found to be significantly more informed about the study, and written consents frequent in patients with either only dientamoe- were obtained. The research was approved by the biasis or only giardiasis, when compared to cases Ethics Committee of the Faculty of Medicine, Celal with no pathogenic parasites (P < 0.001). Clinical Bayar University, in accordance with the Helsinki symptoms in patients with only D. fragilis infec- Declaration. tion, only G. lamblia infection and no pathogenic Comparisons were performed by chi-square parasites are shown in Table 1. tests (Yates corrected). Follow-up controls showed that D. fragilis was eradicated in 31 of 32 patients with only dienta- moebiasis, and in all three cases with both D. RESULTS fragilis and G. lamblia infection, after a single dose Four hundred cases aged between 2 and 60 years of secnidazole, but a second dose was needed for (mean ¼ 21.6 15.0) were examined for intestinal eradication of D. fragilis in one patient. Of the 32 parasites. Of these cases, 35 (8.8%) patients, aged cases with only D. fragilis infection, clinical symp- between 3 and 60 years (mean ¼ 16.9 11.7), were toms disappeared after eradication of the parasite positive for D. fragilis, and 34 (8.5%) patients, aged in 16 of 18 children (88.9%), and in nine of 14 adults between 4 and 55 years (mean ¼ 14.7 11.0), were (64.3%), while they decreased in two children positive for G. lamblia. , Hyme- (11.1%) and five adults (35.7%). In total, clinical nolepis nana and Taenia saginata were detected in cure and decreases in symptoms were observed in six cases (1.5%), two cases (0.5%), and one (0.3%) 25 (78.1%) and seven (21.9%) cases, respectively. case, respectively. The only pathogenic parasite No side effects were observed, except for mild was D. fragilis in 32 patients, and G. lamblia in 30 nausea in two patients. patients. Among all cases, the infection rates were found to be significantly (P < 0.05) higher in the 8– DISCUSSION 15-year age group for dientamoebiasis (14.8%), and in the 8–15- and 0–7-year age groups (13.0% Although previously considered harmless, D. fra- and 12.7%, respectively) for giardiasis. gilis has been associated with a variety of symp- D. fragilis trophozoites could only be detected by toms, mainly diarrhea and abdominal pain [1–4]. trichrome-stained slides in all cases. However, wet In this study, abdominal pain and diarrhea were

ß 2003 Copyright by the European Society of Clinical Microbiology and Infectious Diseases, CMI, 9, 110–113 112 Clinical Microbiology and Infection, Volume 9 Number 2, February 2003 found to be significantly more frequent in patients of these treatments is between five and 21 days with only dientamoebiasis than in cases with no [2,3]. Secnidazole has the advantage of having a pathogenic parasite (P < 0.001). No significant dif- long half-life, which makes possible the single- ferences were observed between cases with only dose application [5,6]. As with other nitroimida- dientamoebiasis and those with only giardiasis for zoles, the activity of secnidazole is these two symptoms. These data represent strong linked to the ferrodoxin oxidoreductase-mediated evidence for the pathogenicity of D. fragilis. reduction of the nitro group, which cannot occur The incidence of D. fragilis infection has been under aerobic conditions. Therefore, secnidazole is reported from different areas of the world in a toxic only for anaerobic organisms such as G. wide range from 1.4% to 52% [1–3, 8]. The organ- lamblia, E. histolytica, and vaginalis [6]. ism was reported to be the most common enter- A single dose of secnidazole was found to be opathogenic parasite in the Sultanate of Oman [9] effective for the eradication of D. fragilis in all of and in US soldiers stationed in Egypt [10]. The low our patients, except for one who needed a second incidence or absence of this organism in different identical dose. This patient was a 55-year-old male surveys may be due to the use of poor laboratory with diarrhea and abdominal pain. His symptoms recovery techniques and/or a general lack of and excretion of D. fragilis trophozoites continued knowledge concerning the parasite. Considerably after the first treatment with secnidazole, but dis- higher incidences of D. fragilis infection were appeared on the seventh and fourteenth days of reported among children than among adults the second treatment. After eradication of D. fra- [1,8]. In this study, the infection rate was found gilis, the symptoms disappeared in 16 of 18 (88.9%) to be significantly (P < 0.05) higher only in the 8– children and nine of 14 (64.3%) adults, and 15-year age group. Among our 400 cases, D. fragilis decreased in all other cases. The high correlation was the most frequently detected parasite, being between eradication of D. fragilis and the disap- detected in 35 cases (8.8%), while G. lamblia and E. pearance or decrease in clinical symptoms sug- histolytica were detected in 34 (8.5%) and six (1.5%) gested that D. fragilis is responsible for these. cases, respectively. The frequencies of these para- Secnidazole was used after dinner, to reduce the sites were probably higher than their incidences in riskofnauseaandvomiting,andnosideeffectswere society, because all of our cases were admitted to observed, except for mild nausea in two patients. the Department of Parasitology due to symptoms These data suggested that D. fragilis is a com- suggesting parasitic infections. mon parasite and causes clinical symptoms as The diagnosis of dientamoebiasis depends on frequently as G. lamblia. Secnidazole may be a the demonstration of the parasite, which typically novel drug in the treatment of dientamoebiasis, has two (or sometimes one) nuclei, each containing with its easy single-dose application and high 4–6 granules. It is reported that a permanent stain effectiveness. To our knowledge, this is the first such as trichrome or iron hematoxylin is obliga- time that secnidazole has been used in the treat- tory in the diagnosis of D. fragilis, and experience ment of D. fragilis infection. More studies are and attention are also required, even when these needed to evaluate the efficacy of different agents stains are performed [1–3,7,8]. D. fragilis tropho- against this parasite. zoites could only be detected by trichrome-stained slides in all of our cases, whereas direct wet smear and formalin–ethyl acetate concentration proce- REFERENCES dures were found to be completely useless for 1. Yang J, Scholten T. Dientamoeba fragilis: a review the recovery of this organism. Of the 35 cases, with notes on its epidemiology, pathogenicity, three were detected in the second and two in the mode of and diagnosis. Am J Trop third stool examination. These findings suggest Med Hyg 1977; 26: 16–22. that a staining method such as trichrome should 2. Turner JA. 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ß 2003 Copyright by the European Society of Clinical Microbiology and Infectious Diseases, CMI, 9, 110–113