Strongyloidiasis--progress in diagnosis and treatment

Strongyloidiasis is an intestinal parasitic disease caused by Strongyloides stercoralis. Basically, detecting larvae of S. stercoralis in feces makes definitive diagnosis. The ordinary agar plate culture method developed at our department is much simpler to handle and much more sensitive than the conventional filter paper culture method. It is considered to be the most useful method in the diagnosis of strongyloidiasis and in evaluation of the eradicating effect. Among chemotherapeutic agents, thiabendazole representing the benzimidazole compounds is most effective. However, it has a problem in safety, since its adverse effects and liver dysfunction occur with a high incidence, and it can be severe. Regarding the effects of mebendazole, albendazole and ivermectin, a study was conducted which included many patients. A high incidence of liver dysfunction was observed with mebendazole, and eradicating effect was not sufficient with albendazole. Ivermectin is different from benzimidazole compounds in a pharmacokinetic profile. However, ivermectin showed a strong anthelmintic effect with the least toxicity. We therefore consider ivermectin is the most useful drug for the treatment of strongyloidiasis.

Varioliform mucosal polypoid lesions in intestinal tract in a patient with adult T-cell leukemia

We describe a case of adult T-cell leukemia (ATL) with intestinal infiltration. In the early clinical stage, the endoscopic findings for the intestine were similar to those of amebic enterocolitis, i.e., varioliform mucosal polypoid lesions, and amebic cyst was detected with stool examination. Although no specific pathological factor could be identified on biopsy, the patient was treated for amebiasis as a diagnostic therapy. The findings of varioliform mucosal polypoid lesions were detected in the duodenum on endoscopic examination, but the lesions eventually disappeared during the treatment for amebiasis. We then suspected lymphoma partially masked by the amebiasis. Immunological staining of a specimen of the colonic mucosa revealed T cell invasion and Southern blotting demonstrated adult T-cell leukemia provirus invasion. Thus, ATL cell infiltration of the intestinal tract was confirmed. It is suggested that systemic disease should also be considered when varioliform mucosal polypoid lesions are found on colonoscopic examination.

A space-occupying lesion in the liver due to Capillaria infection

A space-occupying lesion 3.5 by 2.0 cm in size caused by Capillaria infection was revealed ultrasonographically in segment 6 (S6) of the liver of a 32-year-old woman from Okinawa, Japan, who was hospitalized with a complaint of pain in the right upper quadrant. Laboratory examination showed leukocytosis of 10,400/mm3 with 22% eosinophils and slight impairment of liver function. The tumor was removed surgically and found to be a necrotic granuloma with eosinophilic infiltration formed around a degenerated nematode. The causative agent was presumed to be Capillaria hepatica based on the morphology of the bacillary bands and stichosome observed in the sectioned worm and in the fragments of worm recovered by dissecting the tumor tissue that was embedded in paraffin.

[Clinical study on ivermectin against 125 strongyloidiasis patients]

We treated 125 patients with strongyloidiasis (78 males and 47 females) by 2 oral doses of ivermectin (6 mg) at 2-week interval, and obtained the following results: 1. Eradication rate after treatment was 86.4% (108 of 125 patients), responsively. Out of the total 17 patients were resistant (non-responsive) to treatment, 8 patients received a further course of ivermectin and all Strongyloides stercoralis in their feces were eradicated. 2. Side effects were observed in 7.2% of the patients after the first dose treatment and in 3.2% after the second dose. But all symptoms were mild and self-limited. Although liver disfunction developed in 13.6% of the patients, no symptoms occurred and no special treatment was required. 3. Positive rate of anti-HTLV-I antibody in the resistant group was significantly higher (80.0%) than in the eradicated group (29.2%) and in the stool-negative group (0%). 4. Although eosinophils before treatment in the eradicated group was significantly higher than that of controls, there was no significant difference between the resistant group and controls. IgE levels in the resistant group was significantly lower than in the eradicated group. We would like to conclude that IVM is the best drug for treatment of the patient with Strongyloides stercoralis not only from this results but also our previous reports which had investigated the clinical efficacy on thiabendazole, mebendazole and albendazole.

[Clinical study on symptoms in patients with strongyloidiasis]

We treated strongyloidiasis patients and obtained the following results: Of the 299 patients (184 males and 115 females), 81 patients (27.1%) had no complaints before treatment, 218 patients complaints of some symptoms, including arthralgia and/or lumbago (28.4%), abdominal pain and/or borborygmus (19.3%), numbness of extremities (18.1%), constipation (16.3%) and itching (15.7). We treated 219 patients with mebendazole and symptoms improved after treatment described below: Thirty-seven of the 63 patients (58.7%) with arthralgia and/or lumbago improved. Twenty-seven of the 36 patients (75.0%) with numbness of extremities improved. Thirty-one of the 32 patients (96.9%) with heartburn improved. We treated 26 patients with mebendazole plus thiabendazole and twelve of 14 patients (85.7%) with abdominal pain and/or borborygmus were improved after treatment. We treated 54 patients with ivermectin and five of 18 patients (27.8%) with arthralgia and/or lumbago were improved after treatment.

[Clinical study of albendazole therapy for strongyloidiasis]

We reported the efficacy of albendazole (ABZ) for the treatment of 27 patients with strongyloidiasis. Twenty-seven patients, 23 males and 4 females, received 200 mg of ABZ one hour before breakfast and supper for 3 days and this treatment was repeated 2 weeks later. The following results were obtained: 1) The eradication rate at 2 weeks after the initial treatment was 70.4% (19 of 27 patients) and 2 weeks after the second course was 66.7% (16 of 24 patients). 2) One patients (3.7%) complained of abdominal pain after the first treatment. Four patients (14.8%) complained of headache (n = 2), nausea (n = 1) and exanthema (n = 1) after the second treatment. But all symptoms were mild and required no treatment and subsided in a few days. 3) Positive rate of HTLV-1 antibody was 45.8% in the patients. As described above, side effects occurred in some cases, although they were mild and transient. From these results, it can be concluded that on increased dose of ABZ could be much more favorable for the treatment of strongyloidiasis.

[Clinical study of eradicated and resistant patients to treatment with ivermectin for strongyloidiasis]

We treated 70 patients with strongyloidiasis (41 males and 29 females) with ivermectin (IVM), and obtained the following results: 1. The eradication rates at 1-2 months, 3-4 months and 5-6 months after treatment were 90.7% (49 of 54 patients), 100.0% (47 of 47 patients) and 95.7% (45 of 47 patients), responsively. Twelve patients were resistant (non-responsive) to treatment. 2. When compared to patients whose parasites were completely eradicated, the resistant patients showed the following results: 1) Incidence of symptoms observed before treatment was significantly lower (50.0% vs. 84.5%). 2) Positive rate of anti-HTLV-I antibody was significantly higher (66.7% vs. 20.7%). 3) Blood eosinophil counts before treatment were significantly lower (266.6 +/- 117.2/mm3 vs. 533.2 +/- 429.7/mm3). 4) Serum IgE levels before treatment were significantly lower (217.2 +/- 442.9 IU/ml vs. 1,076.8 +/- 2,108.0 IU/ml). 5) There were no significant differences in age, sex and dosage of ivermectin. 3. Comparing anti-HTLV-I antibody positive and negative patients, the following results were obtained: 1) Eradicated patients; a) Eosinophils and IgE levels before and after the first administration of medicine in anti-HTLV-I antibody positive patients were significantly lower than those of negative patients. b) Gammaglobulin levels before treatment and after both administrations of the drug, IgG before therapy and OKT4/OKT8 after therapy were significantly higher than in anti-HTLV-I antibody positive patients. 2) Resistant patients; Eosinophils after treatment were significantly lower in anti-HTLV-I antibody negative patients than in positive patients.(ABSTRACT TRUNCATED AT 250 WORDS)

[Long term eradication rate of mebendazole therapy for strongyloidiasis]

We treated 245 strongyloidiasis patients with 7 schedules of mebendazole (MBZ) and obtained the eradication rates at 8 months to 2 years after the final treatment as described follows; MBZ (100 mg) was given twice a day orally. [Square bracket shows incidence of liver disfunction.] 1) The eradication rates at 2 years after single course of MBZ therapy for 28 days and a combination therapy (thiabendazole 500 mg powder form three times daily for 5 days followed by MBZ in powder form for 9 days, repeated once) were 93.8% (15 of 16 patients), [71.4%] and 100.0% (16/16), [50.0%]. 2) The eradication rates at 8-15 months after using MBZ alone in varying dosages were as follows: a) MBZ powder was administered for 5 days and was then repeated 1, 3 and 4 weeks later: 87.1 (27/31), [51.1%]. b) MBZ powder was given for 5 days and repeated 1 and 3 weeks later: 100.0% (7/7), [30.8%]. c) MBZ powder was administered for 4 days and repeated 1, 3 and 4 weeks later: 96.3% (26/27), [57.8%]. d) MBZ in tablet form was given for 4 days and repeated 1, 3 and 4 weeks later: 89.6% (43/48). [66.2%]. e) MBZ in tablet form was administered for 4 days and repeated 1 week later: 69.2% (9/13), [25.0%]. As described above, although the incidence of liver disfunction in the 4-day with 2-course therapy was lower than the other schedules, the eradication rate was lower. From these results, MBZ should be given to strongylodiasis patient for 4 days and repeated once, or for 3 days and repeated two or three times with 1 to 2 weeks intervals.