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At least 1,279 records · Page 71Linked to original sources
PubMed1995

Epidemiology and laboratory diagnosis of hantavirus (HTV) infections.

Hantavirus (HTV) is recently discovered "hemorrhagic fever virus" belonging to the Bunyaviridae family, which is spread throughout the world by wild rodents and/or laboratory rats. During an epidemic in the Belgian-French Ardennes in 1993, more than 200 acute cases were recorded of the milder European form of HTV-illness, otherwise known as Nephropathia epidemica (NE). This variant may be recognized by the sudden onset of fever, acute renal failure, thrombocytopenia and sometimes by ophthalmologic complications. The symptomatology is rather aspecific and diagnosis can only be confirmed by serologic tests, of which the best option nowadays seems to be: screening by IgG EIA, followed by IgM confirmation with a mu-capture EIA test. Some of the tests described allow an evaluation of the causative serotype or even the moment of infection. Next to the "classic" serologic assays for detection of specific viral antibodies, we describe briefly our own experience with newer tests such as "high density particle agglutination" and "line immuno assay". Polymerase chain reaction for viral RNA genome typing and immunohistochemical colouring of the viral antigen in tissues seem to offer promising alternatives for the immediate future.

Belgium↗
PubMed1980

Computers in clinical and laboratory diagnosis.

Even though the process of reaching a diagnosis from the available information was first described mathematically over 200 years ago, it is only recently that computers have been applied to the problem. Examples are given to the type of approach that has been used in differentiating between possible alternative causes of conditions such as jaundice or acute abdominal pain and it is shown that the computer programme can give results at least as accurate as the most skilled clinician and usually in a much shorter time. The application of computers to problems of diagnosis in histopathology is discussed and the method of cluster analysis is illustrated in relation to the differentiation between lichen planus and leukoplakia. There appears to be some possibility of identifying patients among the group with leukoplakia who were most likely to develop a carcinoma.

Adult↗
PubMed1993

Clinical and laboratory diagnosis of pertussis in the regions of a large vaccine efficacy trial in Germany.

As a support service for a pertussis vaccine efficacy trial, a central diagnostic laboratory was established. Physicians in the geographic areas of the planned study were encouraged to send nasopharyngeal specimens from children and household contacts with cough illnesses whether or not the illnesses were typical of pertussis. From April, 1991, to February, 1992, 3629 specimens were received and in 601 instances (16.6%) Bordetella pertussis was isolated. Only 3.3% of patients with positive cultures had received pertussis vaccine whereas 16.1% of culture-negative patients had received vaccine (P < 0.0001). Fever was more common (12.2%) in patients with negative cultures compared with those with positive cultures (5.4%) (P < 0.0001). B. pertussis isolation rates fell markedly after 21 days of cough. Significantly more patients with negative cultures compared with those with positive cultures had been treated with erythromycin (8.5 vs. 2.9%; P < 0.0001). Patients with cough for greater than 4 weeks and specimen collection within 2 weeks of cough onset had a B. pertussis isolation rate of 59%. Similarly if whoop occurred under the same circumstances the isolation rate was 80%. In this study 25.5% of patients with culture confirmed pertussis had illnesses with cough of less than 21 days duration. This finding suggests to us that a pertussis case definition in efficacy trials that requires cough of 21 days is excessively restrictive.

Adolescent↗
PubMed2003

[Laboratory diagnosis of dengue virus infections in Aragua State, Venezuela: October 1997-December 1998].

The efficacy of a proactive dengue surveillance system to predict epidemics depends on the laboratory diagnostic capacity for an early detection of virus circulation. This study shows the results of the dengue virologic and serologic surveillance accomplished in Aragua State (Venezuela) from October 1997 to December 1998. Five hundred and forty seven sera from suspected dengue patients were tested using the techniques of Virus Isolation and Immunofluorescence Serotyping (VIIS), Reverse Transcriptase-Polymerase Chain Reaction (RT-PCR), Anti-dengue IgM Capture Enzyme Immunoassay (MAC-ELISA) and Haemagglutination Inhibition test (HI). Of the tested sera, 97.4% resulted positive to at least one technique; of these, 60.4% were classified as confirmed cases (virologically positives) and 39.6% as probable cases (virologically negatives/serologically positives). Though the majority of positive cases occurred during the 1997 and 1998 epidemic periods, the gradual increase of the seropositive rates between both periods suggested the incoming 1998 outbreak. Den-1 (51.2%), Den-2 (37.9%) and Den-4 (10.6%) infected patients were detected as well as one dual infection of Den-2 and Den-4 (0.3%). Dengue hyperendemicity (co-circulation of Den-1, Den-2 and Den-4) in Aragua State was confirmed together with the detection of few cases (6.5%) of Dengue Hemorrhagic Fever/Dengue Shock Syndrome cases (HF/DSS); 38.1% of these cases occurred in patients with secondary infections. The high percentage (85.7%) of DHF/DSS cases infected by Den-2 virus supports the reported virulence of this serotype.

Dengue↗
PubMed2002

Laboratory diagnosis of Bartonella infections.

Bartonella species are pathogens of emerging and reemerging significance, causing a wide array of clinical syndromes. In North America and Europe, they are increasingly recognized as a cause of culture negative endocarditis, neuroretinitis, and disease among homeless, HIV-infected, and other immunosuppressed individuals. In South America, bartonellosis continues to plague those in endemic regions and poses a significant threat to travelers in these areas. As the clinician is increasingly faced with these illnesses, which may be difficult to diagnose, laboratory techniques to confirm or refute the diagnosis are becoming increasingly important. Culture methods have improved over the past decade demonstrating increased sensitivity, but still require prolonged periods before isolation of the organism. Specimen handling, media selection, and growth conditions all may affect results and must be optimized in order to provide the highest likelihood of recovering the organism. Pure culture of the bacteria not only provides morphologic information, but also provides material for further diagnostic testing. Work with liquid media, which may provide a more rapid means of cultivation has shown some promise and should continue to be pursued. Improved blood culture techniques were a primary factor in the discovery of Bartonella endocarditis and continued improvements will likely demonstrate further clinical insights. Serologic testing for B henselae infections has become the cornerstone of clinical diagnosis, replacing the skin test that was poorly standardized and posed a potential risk to the patient. Immunofluorescence assays have been well characterized and validated in clinical trials, however they are not universally available. Vero cell cocultivated antigens appear to provide higher sensitivity and specificity when compared with agar-derived antigens. IFA assays are inherently difficult to perform, requiring significant expertise to provide reproducible results. On the contrary, enzyme immunoassays offer ease of use and a high level of reproducibility, however ideal antigens for use in the diagnosis of Bartonella infections have not been clearly identified. Continued work to define antigenic targets of the human response to infection and incorporation of these into a widely available EIA will provide a cost-effective tool for the clinician and epidemiologist alike. Due to the close phylogenetic relationship of B henselae and B quintana, differentiation between these species by serologic means may prove difficult. Molecular techniques including PCR offer high sensitivity and specificity, rapid availability of information, and the ability to differentiate Bartonella organisms at the highest level. Results of studies to date are promising and as methods are refined it will be important to conduct clinical studies to define the role of these assays. In disseminated Bartonella infections such as bacillary angiomatosis, peliosis, endocarditis, and urban trench fever, PCR currently offers the ability to establish the diagnosis when other tests may be unrevealing. For CSD, this technique should be used as a confirmatory technique when the diagnosis is unclear by other means. PCR analysis of blood specimens offers a minimally invasive approach to diagnosis, but clinical data are scarce and further studies are needed. As DNA microarrays move into the clinical arena, specific hybridization probes may allow improved identification and differentiation of Bartonellae at the molecular level.

Antibodies, Bacterial↗
PubMed2000

Introduction of a rapid dipstick assay for the detection of Leptospira-specific immunoglobulin m antibodies in the laboratory diagnosis of leptospirosis in a hospital in Makassar, Indonesia.

An easy, rapid and robust dipstick assay for detection of leptospira-specific immunoglobulin M (IgM) antibodies was evaluated on 403 patients admitted for hospitalization because of fever. The clinical symptoms and signs of 35 patients were consistent with leptospirosis. The final diagnosis for the remaining patients was as follows: 136 with typhoid fever, 82 with hepatitis, 74 with malaria, 48 with infections of the respiratory tract, and 20 with fever of unknown origin. The clinical diagnosis of leptospirosis was confirmed for 24 (68.6%) patients by the combined results of the microscopic agglutination test (MAT), the reference test for leptospirosis, and of IgM ELISA, a standard laboratory test for the serodiagnosis of leptospirosis. In addition, serum specimens from 8 (2.2%) patients with a final clinical diagnosis other than leptospirosis were found to be positive in MAT and/or IgM ELISA. Compared with the results of MAT and IgM ELISA a sensitivity of 91.6% and specificity of 93.6% was calculated for the dipstick assay. Most of the serum samples from the laboratory confirmed patients gave a moderate to strong staining intensity of the antigen band of the dipstick and were easy to read. The results demonstrate that the dipstick assay is convenient to use and allows the rapid and accurate confirmation of patients with clinical suspicion of leptospirosis in areas where the disease is endemic.

Antibodies, Bacterial↗