Darawan Wanachiwanawin

Efficacy and Safety of Single and Double Doses of Ivermectin versus 7-Day High Dose Albendazole for Chronic Strongyloidiasis

Background Strongyloidiasis, caused by an intestinal helminth Strongyloides stercoralis, is common throughout the tropics. It remains an important health problem due to autoinfection, which may result in hyperinfection and disseminated infection in immunosuppressed patients, especially patients receiving chemotherapy or corticosteroid treatment. Ivermectin and albendazole are effective against strongyloidiasis. However, the efficacy and the most effective dosing regimen are to be determined. Methods A prospective, randomized, open study was conducted in which a 7-day course of oral albendazole 800 mg daily was compared with a single dose (200 microgram/kilogram body weight), or double doses, given 2 weeks apart, of ivermectin in Thai patients with chronic strongyloidiasis. Patients were followed-up with 2 weeks after initiation of treatment, then 1 month, 3 months, 6 months, 9 months, and 1 year after treatment. Combination of direct microscopic examination of fecal smear, formol-ether concentration method, and modified Koga agar plate culture were used to detect strongyloides larvae in two consecutive fecal samples in each follow-up visit. The primary endpoint was clearance of strongyloides larvae from feces after treatment and at one year follow-up. Results Ninety patients were included in the analysis (30, 31 and 29 patients in albendazole, single dose, and double doses ivermectin group, respectively). All except one patient in this study had at least one concomitant disease. Diabetes mellitus, systemic lupus erythrematosus, nephrotic syndrome, hematologic malignancy, solid tumor and human immunodeficiency virus infection were common concomitant diseases in these patients. The median (range) duration of follow-up were 19 (2–76) weeks in albendazole group, 39 (2–74) weeks in single dose ivermectin group, and 26 (2–74) weeks in double doses ivermectin group. Parasitological cure rate were 63.3%, 96.8% and 93.1% in albendazole, single dose oral ivermectin, and double doses of oral ivermectin respectively (Pu200a=u200a0.006) in modified intention to treat analysis. No serious adverse event associated with treatment was found in any of the groups. Conclusion/Significance This study confirms that both a single, and a double dose of oral ivermectin taken two weeks apart, is more effective than a 7-day course of high dose albendazole for patients with chronic infection due to S. stercoralis. Double dose of ivermectin, taken two weeks apart, might be more effective than a single dose in patients with concomitant illness. Trial Registration ClinicalTrials.gov NCT00765024

Treatment of Acanthamoeba keratitis with chlorhexidine

OBJECTIVEnTo evaluate the efficacy of chlorhexidine solution in the treatment of patients with Acanthamoeba keratitis.nnnDESIGNnProspective nonrandomized study.nnnPARTICIPANTSnFive patients infected with culture-proven Acanthamoeba keratitis.nnnINTERVENTIONnChlorhexidine solution was used hourly on six eyes and gradually reduced to four times a day after 1 month. Follow-up ranged from 1 to 10 months (mean, 4 months).nnnMAIN OUTCOME MEASURESnSeverity of symptoms and signs, time for healing, and final visual acuity.nnnRESULTSnClinical results in four patients showed improved visual acuity, with a rapid recovery within 1 week. No adverse drug reaction was encountered, but one patient with a perforated ulcer developed glaucoma. Eighty-three percent of 6 eyes were medically cured with chlorhexidine and recovered visual acuity 6/18 or better. Four of five patients improved within 3 weeks, with resolution of infiltration and healing of epithelial defects. By 2 to 3 weeks, visual acuity 6/18 or better had improved in four (66.7%) of six eyes and recovered 6/6 in two eyes (33.3%). Bacterial coinfection occurred in one eye.nnnCONCLUSIONnChlorhexidine dramatically hastened clinical improvement in all eyes and is a successful medical therapy that has excellent results in patients who are diagnosed early.

Pneumocystis carinii severe pneumonia among human immunodeficiency virus-infected children in Thailand : the effect of a primary prophylaxis strategy

BACKGROUNDnA knowledge of the epidemiology of Pneumocystis carinii pneumonia (PCP) is important for the development of a strategy for primary PCP prophylaxis and empiric treatment for severe pneumonia in HIV-infected children. However, little is known about the epidemiology of PCP in developing countries. Objective. To measure the relative rate of PCP among hospitalized HIV-infected children with severe pneumonia in Bangkok and evaluate the effect of a strategy of primary PCP prophylaxis in HIV-exposed infants.nnnMETHODSnAll HIV-infected children hospitalized from January, 1996, to December, 1997, for severe pneumonia were investigated for PCP with the use of specimens obtained from bronchoalveolar lavage, endotracheal aspiration or lung tissue necropsy. Characteristics associated with severe pneumonia were described, and the differences between PCP and non-PCP in these severely ill children were analyzed. In June, 1996, a strategy of primary PCP prophylaxis using trimethoprim-sulfamethoxazole in all HIV-exposed infants from 1 to 6 month of age was initiated in our institution. The effect of this strategy was evaluated.nnnRESULTSnOf 279 hospitalized HIV-infected children 128 (46%) were diagnosed with pneumonia and 26 (20%) of these had severe pneumonia. P. carinii was identified in 9 (35%) children with severe pneumonia. After June, 1996, the rate of severe pneumonia among all hospitalized children decreased from 16% from January through June, 1996, to 7% from July, 1996, through December, 1997 (P = 0.02). Cases of PCP decreased from 9 in 1996 to zero in 1997. The percentage of HIV-infected children receiving PCP prophylaxis at the time of admission increased from 53% before June, 1996, to 72% in late 1997 (P = 0.04). The overall percentage of patients with severe pneumonia receiving PCP prophylaxis at the time of admission was 34%. Breakthrough PCP occurred in 2 children with poor compliance. Patients with PCP were significantly younger than those without PCP (mean age, 10.6+/-10.6 vs. 29.8+/-28.3 months, P = 0.02).nnnCONCLUSIONnPCP occurred in one-third of cases of severe pneumonia in HIV-infected children in Bangkok. The data suggest that PCP prophylaxis can prevent both PCP and non-PCP.

Prevalence and risk factors of acquiring Strongyloides stercoralis infection among patients attending a tertiary hospital in Thailand

Abstract Objectives: We aimed to determine the prevalence and risk factors for Strongyloides stercoralis infection in adult patients attending Siriraj Hospital, a tertiary hospital in Thailand. Methods: A case–control study was carried out between July 2008 and April 2010. Case and control were identified from 6022 patients for whom results of faecal examination were available. A case was a patient who had S. stercoralis larva detected from faecal examination. Control was randomly selected from patients without S. stercoralis larvae detected in three consecutive faecal examinations. The proportion of control to case was 2 : 1. Demographic and clinical data for the day of diagnosis and retrospectively up to 15 days preceding the date of faecal examination were reviewed from their medical records. Results: Overall, 149 (2.47%) patients had S. stercoralis larvae positive. There were 105 males (70.5%), with the mean (SD) age of 53.9 (17.2) years. A total of 300 controls were selected. Male gender (odds ratio (OR) u200a=u200a 2.79, 95% confidence interval (CI) 1.78–4.27)), human immunodeficiency virus (HIV) infection (OR u200a=u200a 3.23, 95% CI 1.43–7.29), and eosinophilia (OR u200a=u200a 1.81, 95% CI 1.33–2.47) were found to be independent risk factors associated with S. stercoralis infection in this setting. Corticosteroid or other immunosuppressive treatment, and other concomitant illnesses were not associated with increased risk of S. stercoralis infection. Conclusion: In this setting, strongyloidiasis was seen more often in male patients with eosinophilia and with HIV infection. Prevention of fatal complication caused by S. stercoralis by regular faecal examination, or serology for early detection and treatment of undiagnosed S. stercoralis infection, is warranted in these high-risk patients.

A dot-blot and immuno-blot assay for the detection of mosquito saliva specific IgE in mosquito bite allergic subjects

Allergic reactions to mosquito bites are common problems worldwide. The reactions are often cutaneous and difficult to distinguish from non-specific histaminic phenomena. Moreover, the presentation might be similar to be a potential cutaneous sign of mantle cell lymphoma or would be characterized in some cases of natural killer cell lymphocytosis associated with Epstein-Barr virus infection [1]. Therefore, a reliable laboratory test for mosquito bite allergy is required. This study is the first report of a dot-blot assay using purified saliva allergens of Culex quinquefasciatus. The potential clinical relevance of the test as an in vitro diagnostic tool for mosquito bite allergy was evaluated and compared to the previously established immuno-blot assay [2]. Forty nine patients with history of mosquito bite allergy and skin lesions which clinically suggested mosquito bite reactions (19 with immediate reactions, 10 with immediate and delayed reactions and 20 with delayed reactions) were included in this study. A wheal or flare lesion occurred within several minutes and peaked at twenty minutes after an exposure indicates an immediate reaction while an indurated pruritic papule developed within a few hours, peaked at 24–36 h and diminished over several days or weeks indicates a

Rapid Differentiation of Filariae in Unstained and Stained Paraffin-Embedded Sections by a High-Resolution Melting Analysis PCR Assay

BACKGROUNDnApart from infection with human filariae, zoonotic filariasis also occurs worldwide, and the numbers of cases have been increasing steadily. Diagnosis of intact filariae in tissues or organs depends on histological identification. The morphology of parasites in tissue-embedded sections is poor and shows high levels of homoplasy. Thus, the use of morphological characteristics in taxonomic studies is difficult and may not allow a specific diagnosis.nnnMETHODSnHere we report the use of real-time PCR with high-resolution melting analysis (HRM) to detect and identify Brugia malayi, Brugia pahangi, Wuchereria bancrofti, and Dirofilaria immitis in paraffin-embedded sections. Assay specificity was determined using other tissue-dwelling parasites, Angiostrongylus cantonensis, Gnathostoma spinigerum, and Cysticercus cellulosae. We also developed a quick paraffin removal protocol.nnnRESULTSnBoth human and animal filariae in formalin-fixed paraffin-embedded sections (FFPES) were diagnosed and identified rapidly, whereas other parasites were negative. There was no difference in the melting temperature of products amplified from filarial DNA obtained from unstained FFPES and Hematoxylin & Eosin-stained sections. Therefore, the DNA extraction protocols developed in this study could be used for real-time PCR with HRM.nnnCONCLUSIONSnWe report the successful application of a HRM-PCR assay to differentiate four filarial parasites in FFPES, thus providing the pathologist with an effective alternative diagnostic procedure. Furthermore, the quick paraffin removal protocol developed could shorten the duration and number of steps required for paraffin removal using a standard protocol.

Immunochromatographic test for rapid serological diagnosis of human angiostrongyliasis

OBJECTIVESnThe serological diagnosis of human infection with Angiostrongylus cantonensis remains problematic because there are no commercially available validated tests. Most laboratories use domestically prepared tests such as the enzyme-linked immunosorbent assay (ELISA) or immunoblotting. Since laboratory facilities are not always available in endemic areas, we developed and assessed a rapid lateral flow immunochromatographic assay (AcQuickDx Test) to detect anti-A. cantonensis antibodies in human serum.nnnMETHODSnThe test device was assembled with purified 31-kDa glycoprotein as diagnostic antigen and with gold-labelled anti-human immunoglublin-G as the detector reagent. A total of 97 serum samples were tested - 19 samples from clinically diagnosed patients with detectable A. cantonensis-specific antibody in immunoblotting; 43 samples from patients with other parasitic diseases, i.e. gnathostomiasis (n=13), toxocariasis (n=2), trichinellosis (n=2), hookworm infection (n=4), filariasis (n=5), cysticercosis (n=9), paragonimiasis (n=2), opisthorchiasis (n=3), and malaria (n=3); and 35 samples from normal healthy subjects.nnnRESULTSnThe sensitivity, specificity, positive predictive value and negative predictive value of AcQuickDx Test to detect anti-A. cantonensis specific antibodies in serologically confirmed angiostrongyliasis cases, were 100%, 98.72%, 95% and 100%, respectively. Positive AcQuickDx was observed in 1 of 4 cases with hookworm infections. No positive AcQuickDx was observed in cases with other parasitic diseases, and the individual healthy subjects.nnnCONCLUSIONSnAcQuickDx Test is rapid, highly sensitive and specific, and easy to perform without additional equipment or ancillary supplies. It yields results that are interpreted visually, and possesses a long shelf-life at room temperature. Thus, it can be applied as an additional test for clinical diagnostic support of angiostrongyliasis either in conventional laboratories or for remote areas where laboratory infrastructure is not available.