Biomedical subjects

George Watt

Publications and source records attributed to George Watt.

8 recordsLinked to original sources

PubMed2003

Decrease in human immunodeficiency virus type 1 load during acute dengue fever.

Rather than the expected increase in human immunodeficiency virus type 1 (HIV-1) load, there was transient suppression of HIV-1 replication during acute dengue infection in a 29-year-old Thai woman. Acute-phase (but not convalescent-phase) serum samples obtained from an HIV-1-uninfected patient with dengue fever reduced HIV-1 infectivity, as determined by a peripheral blood mononuclear cell assay, suggesting the possibility that HIV-1 replication is suppressed during acute dengue fever, as occurs during some cases of scrub typhus infection and measles.

Acute Disease↗

PubMed2003

Differentiating dengue virus infection from scrub typhus in Thai adults with fever.

Dengue fever and scrub typhus are common infections in Asia that often present as acute febrile illness of unclear etiology. We prospectively evaluated febrile adults presenting to the outpatient department of a hospital in northern Thailand to attempt to identify distinguishing characteristics between the two infections. Fifty-four patients were infected with scrub typhus and 35 were infected with dengue virus. Dengue virus infection was associated with hemorrhagic manifestations, particularly bleeding from the gums, which was reported by 27% of the dengue patients, but by none of the scrub typhus patients (P < 0.001, by Fisher's exact test). A low platelet count (< 140,000/mm3) and low white blood cell count (< 5,000/mm3) were strongly associated with dengue infections: odds ratio = 26.3 (95% confidence interval [CI] = 7.4-93.2) for platelet count and 8.2 (95% CI = 2.6-25.5) for leukocyte count. Prospective evaluations of the usefulness of these simple criteria to differentiate scrub typhus from dengue infection are needed in other areas, particularly where rapid confirmatory diagnostic tests are not available.

Adult↗

PubMed2003

Possible scrub typhus coinfections in Thai agricultural workers hospitalized with leptospirosis.

Possible coinfections with Orientia tsutsugamushi the causative agent of scrub typhus, were prospectively evaluated in rice farmers hospitalized with leptospirosis in Northeast Thailand. Of 22 adults with leptospirosis diagnosed by the microscopic agglutination test, 9 also had serologic evidence of scrub typhus. Of 9 individuals with possible coinfections, 5 had signs or symptoms typical of scrub typhus and atypical of leptospirosis. Patients who appeared to have mixed infections had significantly higher median platelet counts and significantly lower median serum bilirubin and creatinine concentrations (P < 0.05, Mann-Whitney U test) than did individuals with leptospirosis alone. One patient with serologic evidence of scrub typhus and leptospirosis was treated only with penicillin, to which scrub typhus is not sensitive. Respiratory distress worsened during therapy, and the patient died of respiratory failure. Physicians should consider the possibility of scrub typhus infection in leptospirosis patients who respond poorly to treatment or who have atypical disease manifestations.

Adult↗

PubMed2003

Prevalence of relative bradycardia in Orientia tsutsugamushi infection.

We investigated 100 febrile patients infected with Orientia tsutsugamushi (the etiologic agent of scrub typhus) for the presence of relative bradycardia, defined as in increase in heart rate of < 10 beats/minutes/1 degree C increase in temperature. The median heart rate response for the entire febrile scrub typhus population was 9.3 beats/minute/degrees C and the prevalence of relative bradycardia was 53%. The occurrence of relative bradycardia was independent of patient age or gender. There were no differences in median basal temperature or febrile temperature between those patients exhibiting relative bradycardia and those with a normal febrile pulse increase. However, febrile patients with relative bradycardia had a significantly higher resting pulse rate following recovery from infection than did patients who had a normal pulse increase during their illness. These data demonstrate that relative bradycardia frequently accompanies mild infection with O. tsutsugamushi and that baseline cardiovascular parameters may affect the febrile heart rate response to scrub typhus.

Adolescent↗

PubMed2003

Acute undifferentiated fever caused by infection with Japanese encephalitis virus.

To determine the proportion of acute undifferentiated fevers without neurologic deficits related to infection with Japanese encephalitis (JE) virus, flavivirus serology (dengue and JE) was performed in a cohort of 156 adults presenting to a hospital in Chiangrai, Thailand. Recent flavivirus infection was diagnosed for any individual with an IgM result > 40 units. A ratio of dengue virus IgM to JE virus IgM < 0.91 defined a JE virus infection. Diagnostic criteria for Japanese encephalitis were met in 22 individuals (14%), and were unequivocal in 8 patients. The admission findings in these eight subjects were similar to those described for other flavivirus infections. Thrombocytopenia was the most striking laboratory abnormality (median platelet count = 119,000/mm3, range = 44,000-236,000/mm3). Headache (75%), nausea (50%), myalgia (38%), rash (38%), and diarrhea (25%) were the most frequently encountered signs and symptoms. Infection with Japanese encephalitis virus is an underappreciated cause of acute undifferentiated fever in Asia.

Acute Disease↗

PubMed2002

AIDS--past and future.

Explore the source record for details and available documents.

Acquired Immunodeficiency Syndrome↗

PubMed2002

Diagnosis of human leptospirosis by monoclonal antibody-based antigen detection in urine.

Hybridomas secreting specific monoclonal antibodies (MAb) to all members of the genus Leptospira (clone LF9) and those that are specific only to the pathogenic species (clones LD5 and LE1) were produced. MAb LF9, which was immunoglobulin G1 (IgG1), reacted to a 38-kDa component of the sodium dodecyl sulfate-polyacrylamide gel electrophoresis-separated whole-cell lysates of all Leptospira spp., while MAb LD5 and MAb LE1, which were IgG1 and IgG2a, respectively, reacted to the 35- to 36-kDa components of all serogroups of the pathogenic species of LEPTOSPIRA: The MAb LD5 was used in a dot blot-enzyme-linked immunosorbent assay (dot-ELISA) for detecting Leptospira antigen in urine samples serially collected from two groups of patients diagnosed with leptospirosis, i.e., 36 clinically diagnosed patients and 25 Leptospira culture confirmed patients. Their serum samples were tested serologically by IgM Dipstick assay, indirect immunofluorescence assay (IFA), and/or microscopic agglutination test (MAT). Urine samples of 26 patients diagnosed with other illnesses and 120 healthy individuals served as controls. For the first group of patients, who had been ill for an average of 3.4 days before hospitalization, the IgM Dipstick test, IFA, and MAT were positive for 69.4, 70.0, and 85.7% of patients, while the Leptospira antigenuria tested by the MAb-based dot-ELISA was positive for 75.0, 88.9, 97.2, 97.2, and 100% of patients on days 1, 2, 3, 7, and 14 of hospitalization, respectively. All but 1 of 11 patients whose serum samples collected on the first day of hospitalization were IgM seronegative, were positive by urine antigen test on day 1. This is strong evidence that detection of antigen in urine can provide diagnostic information that could be useful in directing early therapeutic intervention. The MAT was positive in 10 of 12 patients (83.3%) of the 25 culture-positive Leptospira patients who had been ill for an average of 5.04 days before hospitalization, and the Leptospira antigen was found in 64.0, 84.0, 96.0, 100, 100, 100, and 100% of the patients' urine samples collected on days 1, 2, 3, 4, 5, 6, and 7 of hospitalization, respectively. Leptospira antigenuria was found in 3 of the 26 patients diagnosed with other illnesses and 1 of the 120 healthy controls. The reasons for this positivity are discussed. The detection of antigen in urine by the monoclonal antibody-based dot-ELISA has high potential for rapid, sensitive, and specific diagnosis of leptospirosis at a low cost.

Animals↗

PubMed2002

Acute scrub typhus in Northern Thailand: EKG changes.

The electrocardiographic (EKG) manifestations of scrub typhus were prospectively evaluated in 29 adult patients who acquired Orientia tsutsugamushi infection in Chiang Rai, Northern Thailand. EKGs were normal in 22 of the 29 patients (76%); minor non-specific changes were found in the other 7 patients; ie ST segment/T wave changes (10%), U waves (7%), and premature ventricular contractions (4%). These results suggest that EKG changes in scrub typhus acquired in areas of diminished antibiotic susceptibility are similar to those observed in O. tsutsugamushi infection acquired elsewhere.

Acute Disease↗