A standard screening test for the early and rapid diagnosis of leptospirosis.

PURPOSE : To perform dark field microscopy (DFM) for detection of Leptospira and to validate the results using Leptospira IgM antibody SERION ELISA test. METHODS : After differential centrifugation of Ruys, DFM was done to demonstrate Leptospira in the blood and SERION ELISA was done for Leptospira IgM antibody in single or paired serum samples. One hundred and eleven cases (39 adults and 72 children) of suspected leptospirosis were included in the study. RESULTS : Anicteric cases accounted for 66.7% (26/39) of adults and complications involving brain, liver, kidney and eyes were seen in 33.3% (13/39). In children, 90.3% (65/72) were anicteric and involvement of brain and liver was seen in 9.7% (7/72) cases. On testing 60 single samples of blood from 23 adults and 37 children, DFM exhibited greater sensitivity of 93.3% (56/60) than that of SERION ELISA for Leptospira IgM antibody (33.3%, 20/60). It was observed that the positivity of DFM decreased from 100% (15/15) to 90.9% (10/11) with increase in the duration of infection for more than one week. ELISA for Leptospira IgM, done on 51 paired blood samples, was positive in 64.7% (33/51) cases when both (first and second) samples were tested while in 45.1% (23/51) cases was positive with first sample alone. 58.8%(30/51) cases were positive by testing second sample. DFM results on paired blood samples showed persistence of Leptospira in 92.9% of cases. CONCLUSION : This study shows the validation of DFM results by SERION ELISA for Leptospira IgM antibody, based on which we recommend that DFM can serve as a standard screening test for early and rapid diagnosis of leptospirosis.

Pre-hospital delay in acute myocardial infarction in an urban Indian hospital: a prospective study.

BACKGROUND: Successful treatment of acute myocardial infarction is dependent on early presentation of the patient to the hospital. The factors that contribute to delay in seeking treatment have not been systematically evaluated in the Indian milieu. METHODS: Patients admitted with acute myocardial infarction to a 125-bed urban community hospital were evaluated prospectively. A record of admission characteristics, prior medical history, pre-hospital symptoms and treatment patterns was completed within 48 hours of each admission. Independent predictors of delayed admission were identified by logistic regression. RESULTS: Of 144 consecutive admissions with myocardial infarction, 133 had completed data as per the protocol [mean (SD) age 59 (12.7) years; 79.6% men]. The distribution of presentation times was skewed, with the mode, median and mean being 1, 3 (interquartile range 1.25-11) and 10.9 (SD 20.5) hours, respectively. Seventy-nine patients (59.4%) consulted a general practitioner prior to hospital referral and 48 patients (36.1%) delayed admission to hospital by more than 6 hours from the onset of symptoms. On multivariate analysis, individuals who were initially seen by a general practitioner (OR 5.57; 95% CI 1.84-16.8) and those over the age of 65 years (OR 3.24; 95% CI 1.06-9.89) were identified as 'delayers', while patients with severe symptoms (OR 0.32; 95% CI 0.12-0.87) or prodromal angina (OR 0.25; 95% CI 0.08-0.82) minimized delay. CONCLUSION: Though 50% of patients with acute myocardial infarction present to hospital within 3 hours, about 36% delay seeking treatment by more than 6 hours. Besides age and the pattern and severity of symptoms, visits to the general practitioner were found to be an independent correlate of delay.

Relative prevalence of hepatitis B viral markers and hepatitis C virus antibodies (anti HCV) in Madurai, south India.

(1) The positivity of HBsAg was 4% (75/1819) whereas anti HCV was present only in 0.75% (27/3574) of blood donors. (2) 5.3% (4/75) of hospital staff had HBsAg alone in their blood samples. One doctor, one Staff nurse, one Lascar and one Sanitary worker were positive for HBsAg. None of them were positive for anti HBcIgm and anti-HCV. (3) 29% (31/115) of suspected hepatitis cases were positive for any one of the viral markers or both. 21% (15/72) of males and 14% (6/43) of females were positive for HBsAg. Whereas only 4% (3/72) of males and 2% (1/43) of females were positive for anti HCW. Both HBsAg and anti HCV were found in 8% (6/72) of males only. The age group predominantly, i.e. in 29 out of 31 cases found positive for HBsAg and/or anti HCV, was above 15 years. Two remaining HBsAg positive cases belonged to the 5 to 14 years age group. 71% (84/115) of suspected hepatitis cases were negative for both HBsAg and anti HCV.

Darkfield microscopic (DFM) and serologic evidences for leptospiral infection in panuveitis cases.

186 out of 226 (82%) panuveitis cases showed the presence of leptospira in their blood samples by dark field microscopy. 75% cases were found positive for leptospira after low speed centrifugation and an additional 7% became positive after high speed centrifugation. Leptospirosis was four times more common in males than in females. The disease was more prevalent in the age group of 15 to 54 years. MAT was performed in 23 cases of which 9 were positive. ELISA was performed in 20 cases of which 9 were positive. DFM was positive in 19 out of these 23 cases. MAT, ELISA and DFM were positive in six cases. Highest antibody titre was found due to L. autumalis alone in two cases, L. autumnalis, and L. pomona in one case, L. bharathy in one case, L. lanka alone in one case and L. pomona one in one case. DFM was found to be more sensitive in a smal number of cases and hence DFM needs further evaluation by other workers in this field.

Maintenance of a Pseudomonas fluorescens plasmid in heterologous hosts: metabolic burden as a more reliable variable to predict plasmid instability.

The stability of a large, multiresistance plasmid, pSCL of P. fluorescens CAS102 was studied in Pseudomonas putida and E. coli under various non-stress conditions. Both the strains lost the plasmid within 25 days when repeatedly subcultured in LB broth without any antibiotic. The transformants survived in sterile soil and water without any marked reduction in the viability. In sterile soil, P. putida lost 93% and E. coli, 98% of their plasmid containing population in 30 days, while in sterile water the plasmid loss was 92.5% and 97% respectively. The two variables, viz. the efficiency of plasmid-partitioning during cell division and measurement of relative specific growth rates of plasmid-plus and plasmid-minus cells which are used to predict plasmid instability cannot be used to predict plasmid loss during starvation. The utility of a third variable, viz. the metabolic burden due to plasmid maintenance in predicting plasmid instability in different hosts is discussed. The rate of plasmid loss was found to be comparatively faster in E. coli than in P. putida. The biosynthetic burden due to plasmid maintenance was also more in E. coli than in P. putida when compared to the plasmid-plus and plasmid-minus cells of the two strains which was evident from the increased nutrient uptake rates (glucose, O2, and amino acid) and increased protein content of the plasmid-plus cells of E. coli. From the results, a correlation could be found between the degree of metabolic burden and the rate of plasmid loss. The reliability of metabolic burden, to predict plasmid instability versus the relative specific growth rates is discussed.

Usefulness of dark field microscopy after differential centrifugation in the early diagnosis of leptospirosis in dog and its human contacts.

1. We found leptospira in the blood of two out of three police dogs by dark field microscopic examination after high speed centrifugation. One dog had fever and the other was asymptomatic. Leptospira could not be seen in the urine of one police dog which died of jaundice. 11 out of 21 human contacts were found to be positive for leptospira after low speed centrifugation and 5 after high speed centrifugation. One child had jaundice and an another child had fever. Others had mild symptoms of headache to none. Dark field microscopy after differential centrifugation is useful in the early diagnosis of leptospirosis and thereby could prevent later complications like jaundice.

Studies on the incidence of leptospirosis and possible transmission of Leptospira during leptospiraemia.

During the year 1991 and in the first half year of 1992 a total of 179 cases and 288 cases respectively were tested for the presence of Leptospira by dark ground microscopy and 86 cases (48%) and 157 cases (54.5%) were found to be positive for Leptospira in their blood samples only. The disease was endemic and more prevalent in the age group of 5 to 14 years and 15 to 54 years and affected both sexes. Clinical categorisation of 169 cases in 1991 and 266 cases in the first half of the year 1992 along with the dark ground microscopy results showed that there was no strict correlation between the concentration of Leptospira in the blood and the severity of infection. Epidemiological data regarding the occupation and the contacts indicated that students and medical staff accounted for more than fifty percent of leptospiral infection and there was the possibility of transmission of Leptospira during leptospiraemia. Dark ground microscopy studies on blood samples from 20 cases who came for repeat testing showed the presence of Leptospira in blood up to 43 days and suggested that the convalescent carrier may have a role in the transmission of Leptospira during Leptospiraemia.

MHA-Tp testing on HIV positive and negative women in vigilance home at Madurai.

In the study group of 94 cases of female prostitutes and their children 55 cases showed positive for HIV infection by ELISA and Western Blot tests. They showed positive also for syphilis in 37 cases by VDRL and in 43 cases by MHA-Tp tests among HIV positive and negative women. The association of HIV infection and syphilis was observed in this study due to sexual transmission of these infections. But congenital spread from infected mother to their children was not observed in this study since both mothers and their children were negative for these infections. MHA-Tp testing confirmed VDRL test results in 27 cases and also increased specificity of MHA-Tp test result over VDRL result in 16 cases and exclusion of biological false positive by VDRL in 10 cases were noticed in this study.