Evaluation in Papua New Guinea of a urine coagglutination test and a Widal slide agglutination test for rapid diagnosis of typhoid fever

Two simple rapid tests for the laboratory diagnosis of typhoid fever were evaluated, a coagglutination test for detecting Salmonella typhi antigens in urine and a Widal slide agglutination for detecting serum antibodies. Ninety-two culture-confirmed typhoid cases were compared with 64 non-typhoid fever patients, 50 close contacts of typhoid patients, 30 vaccinated staff and 72 healthy community members. A strong urine Vi coagglutination was found to be 86.5% sensitive and 91.8% specific for typhoid, but was not always easy to read. The slide Widal H was found to be 99% sensitive and 95% specific whereas the slide Widal O was 98% sensitive and 98% specific. These data suggest that a single slide Widal O, at a reciprocal titre of 40, is the most suitable rapid test for the diagnosis of typhoid in a population with low typhoid antibody levels in the community, few other cross-reacting Salmonella infections, and a tendency for patients to present late in the infection.     

Laboratory evaluation of a simple and rapid latex agglutination assay for the serodiagnosis of typhoid fever

A latex agglutination assay for the serodiagnosis of typhoid fever was evaluated on samples collected from patients with clinical suspicion of typhoid fever in South Sulawesi, Indonesia, where the disease is endemic. The latex assay is very easy to use, gives a rapid result and may be used as a point-of-care diagnostic test. For acute phase samples collected on average 6 days after the onset of illness, the sensitivity is 42.5% for culture-confirmed patients with typhoid fever and the specificity is 96.9%. The sensitivity improved with the duration of illness from 30.8% for samples collected during the first 4-5 days of illness to 45.5% for samples collected between days 7 and 9, and to 84.6% for the samples collected more than 9 days after the onset of illness. Testing of follow-up samples may further improve sensitivity by demonstrating seroconversion.     

基于临床特征及实验室检查构建登革热快速判断分诊模型

目的 基于临床特征及实验室检查构建的诺谟图(Nomogram)建立综合判断分诊模型.方法 将542例发热住院患者按约7 ∶ 3随机分为训练集(n=377)及验证集(n=165).用logistic回归分析筛选与登革热病例显著相关的因素,构建诺谟图预测模型,并进行内部、验证;用受试者工作特征曲线(ROC)分析模型的诊断效...     

Indirect fluorescent antibody test for the diagnosis of yellow fever

The indirect fluorescent antibody (FA) test was evaluated for the serodiagnosis of yellow fever (YF) cases and for detection of antibodies after 17D YF vaccination. Results were compared with those of standard serological tests, reactions with heterologous flaviviral antigens were determined, and both IgM and IgG antibodies were measured. Spot slides of infected Vero cells were used as antigen substrate. In cases of primary YF infection, the FA test for IgG antibodies provided clear diagnostic results. Indirect FA tests with anti-IgG were more sensitive than the complement-fixation (CF) test and showed specificity comparable to the CF and neutralization (N) tests. Cases of YF infection superimposed upon pre-existing heterologous flaviviral immunity developed broadly-crossreactive IgG antibodies. IgM antibodies were highly specific in cases of both primary infection and superinfection but were not consistently present. Most individuals without previous flaviviral exposure who received 17D vaccine failed to develop detectable antibodies by the indirect FA test; of those with pre-existing immunity, 79% developed IgG antibodies. The indirect FA test provides a simple, rapid diagnostic procedure which should be especially useful in on-site epidemiological investigations of YF outbreaks.     

Screening tests for diagnosis of cervical lymphadenopathy presenting as prolonged fever

During a two years period, 16 cases having cervical lymphadenopathy presenting as prolonged fever were studied in Abbassia fever hospital, Cairo, Egypt. Patients were subjected to careful history, thorough clinical examination, complete blood picture, tuberculin test, chest x-ray, Monospot test, indirect fluorescent antibody test for toxoplasmosis, detection of cytomegalovirus antibodies and lymph node biopsy with histopathological examination. Ten within normal subjects were taken as controls. The patients were grouped on histopathological basis into 5 groups: (1) One (6%) of the cases was non-specific lymphadenitis diagnosed by clinical examination of the scalp and leucocytosis with polymorphonuclear predominance. (2) Reactive lymphadenitis included 6 (38%) of the cases. Infectious mononucleosis cases were diagnosed by clinical triad of fever, pharyngitis and cervical lymphadenopathy, relative lymphocytosis, monocytosis and positive monospot test. Cytomegalovirus case was diagnosed by lymphocytosis, monocytosis and negative monospot test. Toxoplasmosis cases were diagnosed by monocytosis, negative tuberculin test and positive indirect fluorescent antibody test. (3) Granulomatous lymphadenitis comprised 6 (3%) of the cases. Tuberculous cases were diagnosed by high ESR and highly positive tuberculin test. Sarcoidosis cases were diagnosed by negative tuberculin test and presence of hilar lymphadenopathy. (4) Non-Hodgkin lymphoma case (6%) was diagnosed by clinical deterioration and total lymph node biopsy. 15) Systemic infections were diagnosed by clinical examination, blood culture for salmonellae and brucellae, Widal and Brucella agglutination tests. It is concluded from this study that screening tests are important aids in the diagnosis of cases of cervical lymphadenopathy presenting by prolonged fever especially if lymph node biopsy and histopathological examination are not available or contraindicated. Tub     

Solid-phase radioimmunoassay techniques for the detection of African swine fever antigen and antibody.

A solid phase radioimmunoassay (RIA) has been successfully developed to measure both African swine fever virus (ASFV) antigen and antibody. Studies show that the assay is reproducible and will detect limiting antigen concentrations equivalent to 50--500 HAD50/ml. Both direct and indirect antibody RIA have been developed and have proved to be approximately 100 times fore sensitive than the complement fixation test at present available and 1000 times more sensitive than the immuno-electro-osmophoresis test for the detection of ASFV antibody.     

Field and laboratory comparative evaluation of ten rapid malaria diagnostic tests

The paper reports on a comparative evaluation of 10 rapid malaria tests available in South Africa in 1998: AccuCheck (AC, developmental), Cape Biotech (CB), ICT Malaria Pf (ICT1) and Pf/Pv (ICT2), Kat Medical (KAT), MakroMal (MM), OptiMAL (OP), ParaSight-F (PS), Quorum (Q), Determine-Malaria (DM). In a laboratory study, designed to test absolute detection limits, Plasmodium falciparum-infected blood was diluted with uninfected blood to known parasite concentrations ranging from 500 to 0.1 parasites per microlitre (P/microL). The 50% detection limits were: ICT1, 3.28; ICT2, 4.86; KAT, 6.36; MM, 9.37; CB, 11.42; DM, 12.40; Q, 16.98; PS, 20; AC, 31.15 and OP, 91.16 P/microL. A field study was carried out to test post-treatment specificity. Blood samples from malaria patients were tested with all products (except AC and DM) on the day of treatment and 3 and 7 days thereafter, against a gold standard of microscopy and polymerase chain reaction (PCR). OP and PS produced fewer false-positive results on day 7 (18 and 19%, respectively) than the other rapid tests (38-56%). However, microscopy, PCR, OP and PS disagreed largely as to which individuals remained positive. The tests were further compared with regard to general specificity, particularly cross-reactivity with rheumatoid factor, speed, simplicity, their ability to detect other species, storage requirements and general presentation.     

Comparison of two combined vaccines against typhoid fever and hepatitis A in healthy adults

A prospective, randomised, observer-blind, comparative study was performed in healthy adults with a new hepatitis A/typhoid combined vaccine, Viatim™, and the marketed Hepatyrix™ vaccine. Both vaccines induced high levels of protective antibodies, but typhoid responses were higher and hepatitis A responses more rapid with Viatim™ compared with Hepatyrix™. Both vaccines were well tolerated, no serious adverse events (SAEs) occurred, but more Viatim™ vaccinees had more mild or moderate local reactions (82.7%) than Hepatyrix™ (53.1%, p < 0.001). In this direct comparison Viatim™ induced more local reactions, but elicited a more rapid and higher immune response to both antigens than Hepatyrix™.     

Comparison of two combined vaccines against typhoid fever and hepatitis A in healthy adults

A prospective, randomised, observer-blind, comparative study was performed in healthy adults with a new hepatitis A/typhoid combined vaccine, Viatim, and the marketed Hepatyrix vaccine. Both vaccines induced high levels of protective antibodies, but typhoid responses were higher and hepatitis A responses more rapid with Viatim compared with Hepatyrix. Both vaccines were well tolerated, no serious adverse events (SAEs) occurred, but more Viatim vaccinees had more mild or moderate local reactions (82.7%) than Hepatyrix (53.1%, p < 0.001). In this direct comparison Viatim induced more local reactions, but elicited a more rapid and higher immune response to both antigens than Hepatyrix.     

Identification of typhoid fever and paratyphoid fever cases at presentation in outpatient clinics in Jakarta, Indonesia

In Jakarta, Indonesia, over 80% of patients with typhoid fever or paratyphoid fever are treated in outpatient settings. In a community-based prospective passive surveillance study, we identified 59 typhoid, 23 paratyphoid fever and 259 non-enteric fever outpatients, all blood culture-confirmed. We compared their symptoms with the aim of developing a clinical prediction rule that may help direct empirical antibiotic treatment to cases with suspected (para)typhoid fever, rather than all febrile patients, or refer patients for additional diagnostic tests. Paratyphoid fever (Salmonella paratyphi A) could not be distinguished clinically from typhoid fever. Decisions on empirical antibiotic treatment and advice on hygiene measures in patients with suspected (para)typhoid fever should take into account chills and absence of cough in the first week of fever and delirium in the second week of illness. This prediction rule increases the likelihood of (para)typhoid fever from 1:10 in the first week to, at most, 2:3 in the second week of a febrile illness. However, we were not able to propose a robust clinical prediction rule that could be used as absolute screening method for decisions on additional diagnostic tests, because of the low sensitivity of presenting symptoms in (para)typhoid fever.     

广西伤寒副伤寒报告病例诊断依据的调查

目的调查广西伤寒副伤寒报告病例的诊断依据,从而了解真实情况,提出相应对策。方法在我区A～E5市(县)内对各医疗单位2002年8～12月期间填报疫情报告卡的伤寒、副伤寒病例按调查表回原医疗机构对其诊断依据、实验室结果、菌型等情况进行调查。结果354例伤寒、副伤寒报告病例的“临床”和“临床 血清学”的诊断率均为39．8％,“病原学”诊断率为17．8％,“临床 流行病学”诊断率为2．8％。病原学诊断率以A地为高(49．0％),其它4地在0％～9．1％之间;分离病原以甲型副伤寒的比例为高(占93．7％)。有病原分型诊断的占59．6％,其中伤寒占33．6％,副伤寒占26．0％;未分型占40．4％。234例无病原学诊断、依靠血清学诊断的病例中有107例肥达氏反应结果与区分的诊断不相符(占45．7％);肥达氏阳性的细菌学符合率为23．5％．47．1％培养阳性患者其肥达氏结果为阴性,20．6％肥达氏阳性的患者其培养结果为阴性。结论应提高各医疗机构报告病例病原学诊断的比例,加强对临床医生的培训,提高其诊断水平和统一诊断标准,提高发现病例的敏感性和准确性;肥达氏反应在伤寒副伤寒的诊断中存在其局限性,病例的诊断及现场疫情控制急需敏感性和特异性均高的快速诊断技术。     

The use of eschar swabs for the diagnosis of African tick-bite fever

African tick-bite fever (ATBF) caused by Rickettsia africae is a frequent cause of fever in returned travelers. Here, we used eschar swabs and/or eschar crust samples for the molecular diagnosis of ATBF in returned travelers. In 4 of 5 patients returning from South Africa, including 3 with negative serology, R. africae was identified by molecular tools targeting 2 different genes. The findings of this study highlight the usefulness of eschar swabs and/or eschar crust samples for the diagnosis of R. africae infection.