基因芯片技术检测恙虫病东方体DNA的方法建立

目的　研制用于东方体检测的基因芯片 ,建立快速、灵敏、特异的恙虫病诊断方法。方法　根据东方体 5 6kD外膜蛋白基因序列 ,设计群特异性引物及探针 ,制备寡核苷酸芯片。用Cy3标记的引物 ,利用不对称PCR技术扩增DNA片段 ,将扩增的DNA片段与芯片上的探针杂交 ,用荧光扫描仪检测并分析信号。结果　建立的基因芯片能够检测恙虫病东方体标准株DNA的特异性荧光信号。具有特异、灵敏、快速的优点。结论　成功制备的基因芯片有望应用于恙虫病东方体多种样本的检测 ,为恙虫病提供最为理想的诊断方法。     

Drug treatment of scrub typhus

Scrub typhus is a vector-borne disease caused by the pathogen Orientia tsutsugamushi. We review the published literature for evidence on drug treatment in scrub typhus. Doxycycline has a proven efficacy in several trials and a meta-analysis, although resistance has been documented in parts of northern Thailand. Macrolides are equally efficacious and have less adverse effects, but they are expensive. Azithromycin is the recommended drug in pregnancy and for children. Rifampicin is effective in areas where doxycycline resistance is present. Quinolones have shown some degree of efficacy but the evidence is scant. Most clinical evidence on drug treatment is from cases of mild-to-moderate scrub typhus. Further study is needed on the efficacy of different antibiotics in the treatment of severe, life-threatening scrub typhus.     

Development and evaluation of a latex agglutination test for the rapid diagnosis of scrub typhus

The purpose of this research was to develop a simple and rapid diagnostic test for scrub typhus using a latex agglutination test (LAT) to detect antibodies against Orientia tsutsugamushi. Five strains of O. tsutsugamushi were propagated in L929 cells. The rickettsiae were purified and concentrated with percoll density gradient centrifugation. A suitable concentration of O. tsutsugamushi soluble antigen was used to sensitize latex to prepare the latex antigen. The specificity, sensitivity, and accuracy of the latex antigen were assessed. The LAT, indirect immunofluorescent antibody test (IFA), and Weil-Felix agglutination test (WF) were compared by testing 109 acute febrile illness cases and 100 confirmed non-scrub typhus cases (50 other febrile disease cases and 50 healthy controls). By using the IFA as the standard reference method, the overall sensitivity, specificity, and accuracy of the LAT were 89.1, 98.2, and 93.6%, respectively. By contrast, the sensitivity of the WF, compared with the IFA, was only 47.3%, while the specificity and accuracy were 92.6 and 69.7%, respectively. Thus, the LAT described here is another important alternative test for the diagnosis of scrub typhus.     

Peritonitis in patients with scrub typhus

Various complications have been reported in scrub typhus cases including acute respiratory distress syndrome, encephalitis, pneumonia, pericarditis, acute renal failure, and acute hepatic failure. Few studies have reported on the gastrointestinal manifestations of scrub typhus. Typical gastrointestinal manifestations in patients with scrub typhus include abdominal pain, nausea, vomiting, hematemesis, melena, and diarrhea. The two cases presented in this study are the first reported cases of peritonitis associated with scrub typhus. This study shows that scrub typhus should also be included in the differential diagnosis of peritonitis in areas where Orientia tsutsugamushi is endemic.     

Electrocardiographic changes in scrub typhus fever

A study of the electrocardiographic findings in 78 patients convalescing from scrub typhus fever is reported. In 34.6 per cent of the patients of this series, symptoms referable to the heart were present. No relationship was found to exist between the subjective symptoms and the electrocardiographic findings. Likewise, no correlation between the severity of the disease and the apparent electrocardiographic abnormalities in the convalescent period could be determined. Patients who developed cardiac failure were more likely to show persistence of multiple abnormalities and to require a more prolonged convalescent period. The tracings of only 13 patients were graded as being within rigid normal limits; in another eight patients there were minor electrocardiographic changes that were placed within normal limits. The remaining 57 patients (73 per cent) showed abnormal electrocardiographic findings as late as six to eight weeks after the onset of the infection. Sinus tachycardia was present in 46.1 per cent and was frequently associated with some other abnormality. Prolonged duration of the P wave appeared in 29.5 per cent. No example of heart block was present. While minor deviations of the QRS complex were quite frequent, associated Q and S waves were present in the same record in only 5.2 per cent of the patients. Large S waves in more than two leads were found in 27 per cent. Low voltage was present in 12.8 per cent of the series. Small Q waves were present in 47.4 per cent of the series. Left axis deviation was seen in 12.8 per cent. In 29.5 per cent of the cases deviations of the RS-T segment occurred, and this was the only finding in 2.6 per cent of the patients studied. The T-wave abnormalities, excluding those in Lead III, totaled 23 per cent. Chest leads, with one exception, were within normal limits.     

Granulomatous hepatitis associated with scrub typhus

A 56 year old patient with scrub typhus infection having unusual presentation of hepatic injury resembling acute hepatitis is described. The clinical features of fever, headache, eschar, lymphadenopathy, lymphocytosis and high Rickettsia tsutsugamushi immunofluorescence titres confirmed the diagnosis of scrub typhus. Acute hepatitis was proven by hepatic biochemical tests and liver biopsy. The patient had a complete recovery soon after antibiotic treatment. The presentation of this case suggests that scrub typhus infection should be included in the list of differential diagnosis of acute hepatitis or granulomatous hepatitis, at least in the Asian Pacific region where scrub typhus still prevails.     

Serodiagnosis of scrub typhus by dot-blot method

Microimmunofluorescence (IF) and immunoperoxidase tests are generally used for the serodiagnosis of scrub typhus. While these tests give satisfactory results in the hands of experienced personnel, they can be troublesome for inexperienced technicians. To develop a simpler diagnostic method, dot-blot assay was examined in this study. Six antigenically distinctive strains of Gilliam, Karp, Kato, Shimokoshi, Kawasaki and Kuroki of Rickettsia tsutsugamushi and a strain of Rickettsia sibirica were dotted on a nitrocellulose sheet by a dot-blot instrument. The sheets were treated with patient sera, followed by peroxidase-conjugated anti-human immunoglobulin-antibody and then with the substrate of the enzyme, and the color development on the dots was compared by naked eye observation. By this procedure, anti-rickettsial antibody-positive patient sera showed clear color development on at least one, usually several dots, while the very faint color was observed by the treatment with antibody-negative sera. On the other hand, it was ascertained that the antigens on nitrocellulose sheets were stable for at least 4 months at room temperature. Therefore the diagnostic kits were prepared, and the practical application of this procedure for diagnosis of scrub typhus were tested in Shizuoka and Miyazaki Prefectural Pabulic Health Laboratories. The results indicated a very good comparability between the dot-blot assay and IF-tests, and this dot-blot method was ascertained as a simple and useful method for the scrub typhus serodiagnosis.     

南平市恙虫病地理流行病学调查报告

南平市地处福建省北部 ,北纬 2 9°15′以南。为丘陵为主内陆山区 ,森林茂密 ,灌木杂草丛生 ,山涧、池塘遍布。崇阳溪、建溪、沙溪、富屯溪流经各县(市 ) ,交汇于延平 ,为闽江的上游。年均温度 17.5～ 19.3℃ ,年降雨量 160 2 .2～ 1989.6ｍｍ ,相对湿度 79%～ 82 % ,属于中亚热带湿润季风气候。外环境适宜恙螨生息繁衍。我市 1957年由邵武县医院报告首例恙虫病病例 ,此后每年各县 (市、区 )均有病例报告。近年来随着老干部野外钓鱼活动和生态旅游的兴起 ,发病率呈明显上升。 1990年停止将本病列入疫情报告 ,误诊严重 ,延误治疗甚至死亡时有…     

Acute myocardial infarction following scrub typhus infection

A case report is described of a patient with cerebral palsy and Meckel's diverticulum presenting with congenital atrioventricular (AV) block. There is limited information of congenital heart block in adults, because most literature has been devoted to congenital heart block in childhood. This unique case is discussed with other patient groups' with congenital AV block. Long-term follow-up of congenital heart block is reviewed together with the concept of prophylactic pacemaker placement in symptom-free adults.     

Electrocardiographic changes in scrub typhus patients.

Ninety-eight cases of scrub typhus were examined electrocardiographically. Various findings beyond the normal range were as follows: In the febrile stage, sinus arrhythmia with some beats below 60 per minute, flat or low T waves in the left precordial leads, sinus tachycardia, ST segment elevation of 4-l mm in V2, prominent u waves measuring 1 mm or more in amplitude, tall and peaked T waves in V2-4, incomplete right bundle branch block, T wave inversion in V3-4, first degree A-V block, Q-Tc interval prolongation, notched T waves in V3, AV junctional escapes, prominent Ta waves or depression of PR segments in V2, and right axis deviation; in the convalescent stage, sinus arrhythmia with some beats below 60 per minute, prominent u waves measuring 1 mm or more in amplitude, tall and peaked T waves in V2-4, flat or low T waves in the left precordial leads, incomplete right bundle branch block, sinus tachycardia, first degree A-V block, Q-Tc interval prolongation, T wave inversion in V3-4, ST segment elevation of 4 mm in amplitude in V2, ventricular premature contractions, atrial premature contractions, and right axis deviation. In comparison with the electrocardiographic findings in 101 asymptomatic normal subjects, flat T waves in the precordial leads, tall and peaked T waves in V2-4 in both acute and convalescent stages, and sinus arrhythmia with some beats below 60 per minute in the convalescent stage were more frequent in cases. Electrocardiographic abnormalities were present most commonly in the acute illness, and our findings support the impression that, with few exceptions, prompt treatment of scrub typhus with antibiotics prevents the serious cardiac complications seen prior to the antibiotic era.     

Acute respiratory distress syndrome in scrub typhus

Scrub typhus is a mite-borne infectious disease caused by Orientia tsutsugamushi. Acute respiratory distress syndrome (ARDS) is a serious complication of scrub typhus. This study retrospectively reviewed the medical records of 72 patients diagnosed with scrub typhus from January 1998 to August 2006 in Kaohsiung Chang Gung Memorial Hospital in Taiwan. Eight of 72 scrub typhus patients with ARDS were included in the study; the other patients without ARDS were used as controls. The mortality rate for the scrub typhus patients with ARDS was 25%. The eight patients seldom had underlying diseases. Initial presentations of dyspnea and cough, white blood cell count, hematocrit, total bilirubin, and delayed used of appropriate antibiotics use were significant predictors of ARDS. Multivariate analysis showed that albumin, prothrombin time, and delayed use of appropriate antibiotics were independent predictors of ARDS. Identification of these relative risk factors may help clinicians evaluate clinical cases of scrub typhus with ARDS.     

Immunohistochemical study of scrub typhus: a report of two cases

Scrub typhus is a zoonotic disease caused by Orientia tsutsugamushi, which is transmitted by chiggers. The target cells of this rickettsia are poorly defined in humans. Immunohistochemical staining of tissue sections of patients with scrub typhus is helpful in investigating the target cells of this rickettsia in different organs. We studied two autopsy specimens by immunohistochemical staining using a specific antibody against O. tsutsugamushi. Rickettsiae were located in endothelial cells in all of the organs evaluated, namely heart, lung, brain, kidney, appendix and skin, within cardiac muscle cells and renal tubular epithelial cells, and in macrophages located in the lymph node, liver and spleen. In conclusion, O. tsutsugamushi may disseminate into multiple organs through endothelial cells and macrophages, resulting in the development of fatal complications.     

恙虫病并发肺炎的临床特征(附15例分析)

恙虫病是一种自然疫源性疾病,在我国东南沿海及西南地区发病率较高.近年来,恙虫病发病有增高趋势,临床表现趋于多样、复杂化,并可导致全身多脏器损害.现将我院1986年6月～ 2000年6月收住的36例恙虫病患者中合并肺炎的恙虫病例15例作一回顾性分析.     

Severe scrub typhus confirmed early via immunohistochemical staining

We describe a case of interstitial pneumonia that was confirmed as scrub typhus by immunohistochemical (IHC) staining of an eschar. When a patient presents with interstitial pneumonia accompanied by generalized lymphadenopathy on the thoracic CT scan, clinicians should suspect scrub typhus, especially when the patient has a history of travel to a scrub typhus-endemic area. IHC staining on an eschar revealed invasion by Orientia tsutsugamushi coccobacilli of the patient's sweat ducts and glands as well as vascular endothelium. IHC staining of an eschar could be used as an early-confirmation diagnostic method to establish scrub typhus.