A school-based approach to the control of urinary schistosomiasis and intestinal helminth infections in children in Matuga, Kenya: impact of a two-year chemotherapy programme on prevalence and intensity of infections

A school- and chemotherapy-based urinary schistosomiasis and intestinal helminth infection control programme was conducted in Matuga Division, Kwale District, Coast Province with teachers taking care of diagnosis, treatment and health education. More than 12 000 children in 36 primary schools were included in the 2-year programme. Results for 20 evaluation schools are presented. Children with haematuria were treated with praziquantel (40 mg/kg) once a year. Within 2 years, the prevalence of haematuria in the schools was reduced from 28% (range 8–68%) to 11.4% (range 3–23%). More than 80% of the schoolchildren were infected with one or more intestinal helminths at baseline. After one year with levamisole mass chemotherapy, single dose (2.5 mg/kg) three times a year (once per school term), the prevalence of Ascaris infection was reduced by 83% from 18% to 3%, but there was no change in pretreatment prevalences of hookworm (57%) and Trichuris (56%) infections. In the second year of the programme, albendazole 600 mg once every six months was administered to the children in 10 randomly selected schools. This resulted in 52% and 23% reductions in prevalences of hookworm and Trichuris infections, respectively, in these schools and a reduction in mean intensity of infection of 52.8% and 50.3%, respectively.     

一种改良的布鲁氏菌病抗体微量凝集检测方法的建立与评价

目的 建立一种微量的布鲁氏菌病抗体凝集检测方法,用于布鲁氏菌病高通量检测。方法 依据我国《布鲁氏菌病诊断标准》(WS269-2007)规定的病人诊断标准,用试管凝集试验做诊断标准。通过优化微量凝集试验抗原浓度,对142份疑似病人血清同时做试管凝集和微量凝集试验,进行效果评价。结果 最优的微量凝集抗原浓度为1:10,建立微量凝集法具有较高的敏感度和特异度,分别为98.9%和92.3%;和常规试管凝集法相比,两种方法符合率为96.5%。常规试管凝集检测得到21份阴性样本,22份可疑样本(1:50),99份阳性样本(>1:100)。微量凝集检测得到30份阴性样本、17份可疑样本(1:50)、95份阳性样本(>1:100)。两种试验方法,结果相同的占70.4%(100/142),经统计学检验差异无统计学意义(χ²=0.8,P>0.05)。结论 建立一种可显色的布鲁氏菌病抗体微量凝集检测方法,可以在96孔V型板上同时检测24份标本,且结果易判读,更适宜基层防疫人员现场检测,最终为疫情处置提供强有力的技术支持。     

血吸虫病不同流行程度流行区IHA法阳性诊断阈值的研究

目的 探讨日本血吸虫病不同流行程度流行区IHA法的阳性诊断阈值。方法 选择江西省鄱阳湖区湖沼型血吸虫病流行区2个县（余干和星子）共55个自然村作为研究现场,对5岁以上常住居民采用病原学方法（Kato?Katz法+尼龙绢集卵孵化法）和血清学方法（IHA法）进行平行检测;检测结果采用相关分析和ROC曲线等方法分析,计算不同流行程度流行区IHA抗体水平阳性临界值。结果 血吸虫病流行区人群粪检阳性率与人群IHA血吸虫病特异性抗体水平分布趋势一致（r = 0.588, P ＜ 0.05）,与IHA阳性人群抗体水平无相关性（r = 0.221,P ＞ 0.05）;流行区2008-2011年连续4年血吸虫粪检阴性人群的IHA阳性抗体水平呈逐年下降趋势,年间差异有统计学意义（F = 3.650,P ＜ 0.05）,2008-2011年中任意1年血吸虫粪检阳性人群的IHA阳性抗体水平在4年内均维持较高水平且年间差异无统计学意义（F = 2.461,P ＞ 0.05）。流行村人群粪检阳性率< 1%、1%～5%和> 5%时,对应IHA的阳性诊断阈值分别为1∶80、1∶20和1∶10时,可提高IHA检测结果的特异性。结论 不同程度流行区采用IHA筛查血吸虫病或选择化疗对象时,可考虑选择不同的IHA阳性诊断阈值。     

Evaluation of the Kudoh swab method for the culturing of Mycobacterium tuberculosis in rural areas

Objective  To compare the simple, swab 'Kudoh method' for culturing Myobacterium tuberculosis from sputum samples, to the standard Petroff digestion-decontamination procedure. The Kudoh method, which requires no centrifugation and takes only 4–5 min per sample, was also evaluated for its performance in a rural setting.
Methods  Two hospital laboratories in Caracas, Venezuela processed 314 sputum samples, in parallel, with both methods. Separately, sputum specimens were cultured with the Kudoh swab method in a field environment with minimal laboratory facilities.
Results  In the hospital laboratories, the sensitivity of the Kudoh swab method was comparable to that of the standard Petroff culture procedure. The swab method also performed satisfactorily in the field, improving the diagnostic sensitivity by 21% over microscopic examination alone.
Conclusion  The Kudoh swab method is an acceptable alternative for culturing mycobacteria that is particularly suitable for rural laboratories lacking adequate infrastructure for the Petroff method.     

Accuracy of the Kato-Katz, adhesive tape and FLOTAC techniques for helminth diagnosis among children in Kyrgyzstan

The purpose of this study was to assess the accuracy of three copro-microscopic techniques for helminth diagnosis: Kato-Katz, adhesive tape and FLOTAC. A total of 163 children from a peri-urban municipality near Bishkek, Kyrgyzstan, participated and submitted multiple stool samples and adhesive tapes. Ninety children supplied at least two stool samples and two adhesive tapes. Three stool samples and three adhesive tapes were available from 71 and 64 children, respectively. From each stool sample, a single Kato-Katz thick smear was prepared and examined quantitatively. Additionally, the first stool sample was subjected to the FLOTAC technique and helminth eggs were counted. Adhesive tapes were checked for the presence of Enterobius vermicularis eggs. Using pooled results as a diagnostic ‘gold’ standard, the prevalence of Ascaris lumbricoides, E. vermicularis, Hymenolepis nana and Dicrocoelium dendriticum were 54.4%, 13.3%, 11.1% and 11.1%, respectively. Infection intensities were low. When compared to triplicate Kato-Katz, a single FLOTAC was more sensitive for the diagnosis of A. lumbricoides (89.5% versus 39.5%) and D. dendriticum (88.9% versus 33.3%), but less sensitive for H. nana (66.7% versus 88.9%). For E. vermicularis, three adhesive tapes showed much higher sensitivity than a single FLOTAC (92.9% versus 14.3%). FLOTAC yielded significantly higher faecal egg counts than Kato-Katz for A. lumbricoides and D. dendriticum. Overall results suggest that, although FLOTAC represents a promising technique for helminth diagnosis in Kyrgyzstan, the repeated adhesive tape test remains so far the method of choice for diagnosing E. vermicularis.     

Diagnostic value of endoscopy for the diagnosis of giardiasis and other intestinal diseases in patients with persistent diarrhea from tropical or subtropical areas

Objective. Upper endoscopy has been suggested as a valuable tool in the diagnosis of giardiasis. The aim of this study was to compare two methods based on endoscopy, i.e. microscopy of duodenal fluid and histology, with a fluorescent-antibody assay for the detection of Giardia lamblia cysts in stool specimens. The role of endoscopy in the identification of other causes of chronic diarrhea acquired during travel abroad was also evaluated. Material and methods. Thirty-one patients (9 F, 22 M, median age 39 years, range 19–63 years) with persistent diarrhea after returning from tropical or subtropical areas agreed to undergo upper gastrointestinal endoscopy before and after treatment. Lower gastrointestinal endoscopy was subsequently performed. Three stool samples from each patient were examined using the direct fluorescent-antibody assay (DFA) for the detection of G. lamblia, and by routine methods for other protozoal and bacterial enteric pathogens. Each patient underwent upper endoscopy and biopsies and duodenal fluid samples were taken. In 12 patients a further lower endoscopy was performed. Results. In 16 patients G. lamblia was detected in stool samples by DFA (relative sensitivity: 100%). Histology of duodenal biopsies and microscopy of duodenal fluids allowed diagnosis of giardiasis to be made in only 8, and 3 patients, respectively (relative sensitivities: 21% and 44%). Besides giardiasis, upper endoscopic examination revealed an alternative diagnosis (tropical sprue), whereas six additional diagnoses were made by colonoscopy. In six patients the cause of chronic diarrhea remained unclear. Conclusions. Compared to stool examinations using DFA, upper endoscopy is less sensitive for the diagnosis of giardiasis. In patients with negative stool examinations, lower endoscopy yields relevant diagnoses more often than upper endoscopy.     

Laboratory diagnosis of pulmonary tuberculosis in TB and HIV endemic settings and the contribution of real time PCR for M. tuberculosis in bronchoalveolar lavage fluid

Background Tuberculosis (TB) in Africa is increasing because of the human immunodeficiency virus (HIV) epidemic, and in HIV/AIDS patients it presents atypically. Pulmonary tuberculosis (PTB) in Africa is mainly diagnosed clinically, by chest radiograph or by sputum smear for acid fast bacilli (AFB). Methods We evaluated in 120 HIV‐infected patients with chest infection the diagnostic accuracy of AFB smear of sputum and bronchoalveolar lavage (BAL) fluid, sputum Mycobacterium tuberculosis (MTB) culture, real‐time PCR and MycoDot^® serological test, using MTB culture of BAL fluid as gold standard. We correlated PCR cycle threshold values (C_T) to the culture results. Retrospectively, we evaluated the development of active TB in patients with positive PCR but negative culture. Results Culture of BAL fluid identified 28 patients with PTB. Fifty‐six patients could not produce adequate sputum. Sputum AFB smear and the serological test had sensitivities of 66.7% and 0%, respectively. PCR with C_T 40 was positive in 73 patients, 27 of whom were also TB culture positive (96.4% sensitivity and 52.3% specificity of PCR). PCR with C_T 32 had sensitivity of 85.7% and specificity of 90.9% to diagnose PTB in BAL. No patients with positive PCR but negative culture developed active TB during 18 months follow‐up. Conclusion In these HIV‐infected patients, AFB smear and serology had very low sensitivities. PCR of BAL with C_T value 32 had improved specificity to diagnose active PTB. A prospective follow‐up study is warranted in TB/HIV endemic settings, applying real time PCR to both sputum and BAL.     

Development of an ELISA method for testing VWF ristocetin cofactor activity with improved sensitivity and reliability in the diagnosis of von Willebrand disease

Objectives: Current methods in assessing von Willebrand factor (VWF) ristocetin cofactor activity for Von Willebrand’s disease (VWD) diagnosis include platelet agglutination by aggregometer or macroscopic slide examination, which are both time‐consuming with suboptimal interassay and intra‐assay variation. The purpose of this study is to establish a sensitive assay to detect VWF:RCo activity and evaluate its performance in VWD diagnosis. Methods: We have established a sensitive VWF:RCo–ELISA method using a monoclonal antibody, SZ‐151, to immobilize the recombinant fragment of platelet glycoprotein Ib (rfGPIbα). VWF was captured by rfGPIbα in the presence of ristocetin, and then detected by HRP‐conjugated rabbit anti‐human VWF IgG. We tested the VWF:RCo level by this VWF:RCo–ELISA in 25 patients with different types of VWD and 36 healthy donors, and compared this method to a previously reported ELISA using 2D4 coating antibody. Results: The sensitivity of VWF:RCo–ELISA was greatly improved with this assay (0.008 IU/dL compared to 0.031 IU/dL by 2D4 antibody). The interassay and intra‐assay coefficient variation were 8% and 12%, respectively. The mean values (ranges) of VWF:RCo in patients with type 1, type 2A, type 2B, type 2M, and type 3 of VWD and control group are 31.8 (22.3–56.9), 4.8 (0.6–11.8), 8.6 (1.6–19.7), 3.9 (1.0–6.8), 1.0 (0.5–1.6), and 91.5 (47.3–169.2) IU/dL, respectively. The corresponding ratios (ranges) of VWF:RCo / VWF:Ag are 0.83 (0.70–1.16), 0.27 (0.08–0.58), 0.31 (0.15–0.40), 0.18 (0.14–0.21), 0.52 (0.13–1.19), and 0.92 (0.62–1.26). Conclusion: The VWF:RCo–ELISA using monoclonal anti‐rfGPIbα antibody SZ‐151 showed improved sensitivity and reliability in detecting VWF:RCo activity, and its clinical application would facilitate the diagnosis and classification of VWD.     

Development and validation of a fast HPLC/photodiode array detection method for the measurement of voriconazole in human serum samples. A reference laboratory experience

The aim of this study was the development and validation of a fast and simple high performance liquid chromatography method for measuring voriconazole in human serum using ravuconazole as an external standard. The experience of the reference laboratory in therapeutic drug monitoring of voriconazole is also reported. This method is based on the precipitation of proteins in human serum and detection by HPLC/UV. Chromatographic separation is achieved using an isocratic solvent delivery with detection at 255 nm and a run time of 7 min. The assay was validated according to international guidelines and was also applied to the analysis of 141 trough serum samples from patients treated with voriconazole. All validation parameters met the criteria set out in FDA guidelines for bioanalytical methods. A high interpatient and intrapatient variability was observed in clinical samples. This method is accurate enough to perform therapeutic drug monitoring in patients receiving voriconazole treatment.