Epidemiology & risk factors of scrub typhus in south India.

Background & objectives: Scrub typhus is a major public health threat in South and Southeastern Asian countries including India. Understanding local patterns of disease and factors that place individuals at risk is pivotal to future preventive measures against scrub typhus. The primary aim of this study was to identify specific epidemiological and geographical factors associated with an increased risk of developing scrub typhus in this region. Methods: We mapped 709 patients from Tamil Nadu, Andhra Pradesh and Telangana who were admitted to the Christian Medical College (CMC) Hospital, Vellore, Tamil Nadu, India, for the period 2006-2011, assessed seasonality using monthly counts of scrub typhus cases, and conducted a case-control study among a subset of patients residing in Vellore. Results: The geographic distribution of cases at CMC Hospital clusters around the Tamil Nadu-Andhra Pradesh border. However, distinct hotspots clearly exist distal to this area, near Madurai and the coast in Tamil Nadu, and in the Northeast of Andhra Pradesh. Seasonally, the highest numbers of cases were observed in the cooler months of the year, i.e. September to January. In the case-control analysis, cases were more likely to be agricultural laborers (OR 1.79, 95% CI 1.01 - 3.15), not wear a shirt at home (OR 4.23, 95% CI 1.12 - 16.3), live in houses adjacent to bushes or shrubs (OR 1.95, 95% CI 1.08 - 3.53), and live in a single room home (OR 1.75, 95% CI 1.02 - 3.01). On binary logistic regression, the first three of these variables were statistically significant. Interpretation & conclusions: With the growing number of cases detected in India, scrub typhus is fast emerging as a public health threat and further research to protect the population from this deadly infection is essential. Health education campaigns focusing on the agricultural workers of Southern India, especially during the cooler months of the year, can serve as an important public health measure to control infection.

Study of Common Illnesses Before and After Vaccination: A Risk-interval Approach.

Objective: To compare the proportion of children who developed a specified illness in the 7 day post-vaccination window, with the background rate of the same event in the 7 day pre-vaccination window. Study design: Risk interval approach (Self-controlled caseseries). Setting: Well Baby Clinic of Christian Medical College, Vellore. Participants: 1602 healthy infants and under-six children presenting for routine vaccination. Outcome measures: Episode of any illness. Methods: The interviewer enquired about any adverse event or illness experienced by the child for each day of the week preceding the administration of age-appropriate vaccines. A second interview (telephonic) was conducted by the same interviewer one week following vaccine administration to enquire about adverse event(s) experienced by the child for each day of the subsequent week using a similar protocol. Results: With multiple vaccines delivered at appropriate ages, common childhood illnesses that could be reported as adverse events following immunization, except fever (RR=5.7, 95% CI=4.50-7.35), occurred at higher rates pre-vaccination. Risk Ratios of fever following whole cell (RR=9.3, 95% CI=6.43-13.52) and acellular (RR=8.5, 95% CI=3.82-18.91) vaccines were similar, with both showing a decreasing trend with increasing age. The gastrointestinal adverse event profile [diarrhea (RR=0.6, 95% CI=0.14-2.51) and vomiting (RR=1.0, 95% CI=0.14-7.10)] for rotavirus vaccine was similar pre- and post-immunization. Conclusions: Since most adverse events to vaccines are also common childhood illnesses, estimating the background rates of common illnesses is important to accurately ascertain a causal relationship.

Prevalence & risk factors for soil transmitted helminth infection among school children in south India.

Background & objectives: Soil-transmitted helminths (STH) are a major public health problem in tropical and sub-tropical countries, affecting the physical growth and cognitive development in school-age children. This study was aimed to assess the prevalence and risk factors of STH infection among school children aged 6 -14 yr in Vellore and Thiruvanamalai districts in south India. Methods: Children aged 6-14 yr, going to government and government aided schools (n=33, randomly selected) in Vellore and Thiruvanamalai districts were screened to estimate the prevalence of STH, and a case control study was done on a subset to assess the risk factors for the infection. Results: The prevalence of STH was 7.8 per cent, varying widely in schools from 0 to 20.4 per cent, in 3706 screened children. Hookworm (8.4%) rates were high in rural areas, while Ascaris (3.3%) and Trichuris (2.2%) were more prevalent among urban children. Consumption of deworming tablets (OR=0.25, P<0.01) offered protection, while residing in a field hut (OR=6.73, P=0.02) and unhygienic practices like open air defaecation (OR=5.37, P<0.01), keeping untrimmed nails (OR=2.53, P=0.01) or eating food fallen on the ground (OR=2.52, P=0.01) were important risk factors for STH infection. Interpretation & conclusions: Our study indicated that school children with specific risk factors in the studied area were vulnerable subpopulation with elevated risk of STH infection. Identifying risk factors and dynamics of transmission in vulnerable groups can help to plan for effective prevention strategies.

Birthweight Centile Charts from Rural Community-based Data from Southern India.

Objective: The objectives of the study were to estimate gestational age specific birthweight centiles from healthy pregnancies in a defined rural block and compare the under-two month mortality rates in those belonging to the lowest and highest centile groups. Design: Retrospective chart review. Setting: Routine data collected regarding all pregnancies, births and deaths occurring in Kaniyambadi, a rural block in Southern India, between 2003 to 2012. Subjects: All singleton live newborns of women without known major antenatal risk factors. Main outcome measures: Gestational age- and sex-specific birthweight centile curves were created using the LMS method. Mortality rates for the first two months of life were calculated for those in various centile groups. Results: The median birthweight at term was lower for the study subjects as compared to the median birth weights in the WHO child growth standards 2006, the US and the UK standards. Mortality rates for those with birthweights both below the 3rd centile as well as above the 97th centile higher than for those between 3rd and 97th centiles. Conclusions: While absolute values of birthweights were lower than the WHO 2006 child growth standards there was a J shaped curve of birthweight and mortality. This suggests that in a given population, mortality increases at extremes of birthweights, even if some of these birthweights may be considered normal by other standards.

Evaluation of a programme for prevention of vertical transmission of hepatitis B in a rural block in southern India.

Background & objectives: This study was undertaken to evaluate a community based programme of antenatal screening for hepatitis B surface antigen (HBsAg) and selective immunization of children commencing at birth, at a secondary care hospital in south India. The primary objective was to assess immunization coverage among children born to HBsAg positive women; secondary objectives were to study the prevalence of HBsAg among antenatal women, prevalence of HBsAg among immunized children (to estimate vaccine efficacy), seroconversion rate and relationship of maternal hepatitis B e antigen (HBeAg) to hepatitis infection. Methods: The prevalence of hepatitis B antigen among antenatal women and immunization coverage achieved with hepatitis B vaccine in a rural block in Vellore, Tamil Nadu were assessed through examination of records. Children born between May 2002 and December 2007 to hepatitis B positive women were followed up for a serological evaluation, based on which vaccine efficacy and the effect of maternal hepatitis B e antigen (HBeAg) on breakthrough infection was estimated. Results: The prevalence of hepatitis B surface antigen among antenatal women was 1.58 % (95% CI: 1.35-1.81%). Vaccine coverage for three doses as per a recommended schedule (including a birth dose) was 70 per cent, while 82.4 per cent eventually received three doses (including a birth dose). Estimated vaccine efficacy was 68 per cent and seroconversion 92.4 per cent in children aged 6-24 months. Maternal HBeAg was significantly associated with either anti-HBc or HBsAg in immunized children, RR=5.89 (95% CI: 1.21-28.52%). Interpretation & conclusions: The prevalence of hepatitis B among antenatal women in this region was low and a programme of selective immunization was found to be feasible, achieving a high coverage for three doses of the vaccine including a birth dose.

Correlation between ocular parameters and amplitude of accommodation.

Aim: To study the relationship between ocular parameters and amplitude of accommodation (AA) in the peri-presbyopic age group (35–50 years). Materials and Methods: Three hundred and sixteen right eyes of consecutive patients in the age group 35–50 years, who attended our outpatient clinic, were studied. Emmetropes, hypermetropes and myopes with best-corrected visual acuity of 20/20, J1 in both eyes were included. The AA was calculated by measuring the near point of accommodation. The axial length (AL), central anterior chamber depth (CACD) and lens thickness (LT) were also measured. Results: There was moderate correlation (Pearson’s correlation coefficient r = 0.56) between AL and AA as well as between CACD and AA (r = 0.53) in myopes in the age group 35–39 years. In the other age groups and the groups taken as a whole, there was no correlation. In hypermetropes and emmetropes, there was no correlation between AA and the above ocular parameters. No significant correlation existed between LT and AA across different age groups and refractive errors. Conclusion: There was no significant correlation between AA and ocular parameters like anterior chamber depth, AL and LT.

Prevalence of proteinuria in rural adult population in Tamil Nadu.

BACKGROUND & OBJECTIVES: Presence of proteinuria is considered as an early marker of an increased risk of progressive kidney disease. Angiotensin converting enzyme (ACE) inhibitors (ACEi) and angiotensin II receptor blockers (ARB) treatment to persons with proteinuria and chronic kidney disease has been shown to decrease the progression to endstage renal disease. As the exact prevalence of proteinuria is not known in the general population, we undertook this study to estimate the same in a rural adult population in Vellore district, Tamil Nadu. METHODS: A convenient sample of 5,043 adults was included. All individuals were tested for albuminuria by albumin dipstick examination in an untimed urine sample. Individuals who tested positive for albuminuria underwent a second dipstick examination after a gap of one week. Individuals with persistent albuminuria on the second dipstick examination underwent further evaluation which included medical history, physical examination, 24 h urine protein estimation, total serum protein and albumin estimation. Ultrasound of the abdomen was done in patients with renal failure and renal biopsy was performed in selected patients. RESULTS: Of the total 5,043 individuals screened, 63.1 per cent were females. Mean age of the study population was 50.94 +/- 11.2 yr. First dipstick test identified 594 individuals positive for albuminuria. Repeat dipstick could be done in only 576, of whom 212 showed persistent albuminuria. Significant proteinuria was detected in 24 individuals of the 208 who had 24 h urine protein measured. Of these 24 patients, 3 were found to have chronic renal failure, 12 were presumed to have diabetic nephropathy clinically, one each had focal segmental glomerulosclerosis and biopsy proven diabetic nephropathy, and 7 patients had proteinuria of unknown aetiology. INTERPRETATION & CONCLUSION: The prevalence of proteinuria in this adult rural population was 0.47 per cent (0.30-0.67%). The detection and treatment of chronic kidney disease in 24 individuals is bound to reduce the rate of decline of renal functions. Screening programme for proteinuria in different parts of country may be an effective measure to bring a decline in rate of progression of chronic kidney disease in general population.

Role of frequency doubling technology perimetry in screening of diabetic retinopathy.

PURPOSE: To study the ability of frequency-doubling technology perimetry (FDT) to detect sight-threatening diabetic retinopathy. METHOD: Fifty-eight eyes of fifty-eight patients with established diagnosis of diabetes mellitus with diabetic retinopathy, fifty-five eyes of fifty-five diabetic patients without retinopathy and forty-one eyes of forty-one normals underwent FDT and dilated stereo-biomicroscopic fundus examination. The sensitivity and specificity of FDT in identification of "sight-threatening retinopathy" (severe and very severe nonproliferative diabetic retinopathy and proliferative diabetic retinopathy) and clinically significant macular edema (CSME) were determined. RESULTS: For the detection of sight-threatening retinopathy, two abnormal adjacent points depressed to any level on the 20-1 screening program had a sensitivity of 90.5% and specificity of 97.6%. At (assuming a) 10% prevalence of sight-threatening retinopathy in a diabetic clinic, two abnormal adjacent points anywhere in the field depressed to any level has a positive predictive value (PPV) of 48% with a negative predictive value of 98.8%. Sensitivity and specificity for the detection of CSME was poor. CONCLUSIONS: The 20-1 screening program of the FDT is useful in the detection of sight-threatening diabetic retinopathy (PPV 48%). A normal 20-1 test rules out sight-threatening retinopathy. FDT was not useful in the detection of CSME.

Amplitude of accommodation and its relation to refractive errors.

AIMS: To evaluate the relationship between amplitude of accommodation and refractive errors in the peri-presbyopic age group. MATERIALS AND METHODS: Three hundred and sixteen right eyes of 316 consecutive patients in the age group 35-50 years who attended our outpatient clinic were studied. Emmetropes, hypermetropes and myopes with best-corrected visual acuity of 6/6 J1 in both eyes were included. The amplitude of accommodation (AA) was calculated by measuring the near point of accommodation (NPA). In patients with more than +/- 2 diopter sphere correction for distance, the NPA was also measured using appropriate soft contact lenses. RESULTS: There was a statistically significant difference in AA between myopes and hypermetropes (P < 0.005) and between myopes and emmetropes (P < 0.005) in the 35-39 year age group. In the 40-44 year age group, there was a significant difference in AA between emmetropes and hypermetropes (P < 0.0001), emmetropes and myopes (P < 0.01) and hypermetropes and myopes (P < 0.0001). In patients above 45 years of age there was no significant difference (P > 0.5). CONCLUSION: Our study showed higher amplitude of accommodation among myopes between 35 and 44 years compared to emmetropes and hypermetropes.

Five-year risk of progression of ocular hypertension to primary open angle glaucoma. A population-based study.

PURPOSE: To report the progression of ocular hypertension (OHT) to primary open angle glaucoma (POAG) during a 5-year follow up of a population-based sample. METHODS: Twenty-nine patients diagnosed to have OHT and 110 randomly selected normals from a population-based study in 1995 were invited for ocular examination in 2000. All patients underwent a complete ophthalmic examination; including the daytime diurnal variation of intraocular pressure (IOP) and measurement of central corneal thickness (CCT). The "corrected" IOP was used for analysis. Progression to POAG was based on typical optic disc changes with corresponding field defects on automated perimetry. RESULTS: Twenty-five of the 29 persons with OHT who could be contacted were examined. After correcting for CCT, two persons were reclassified as normal. Four of 23 (17.4%; 95% CI: 1.95-32.75) had progressed to POAG. One person amongst the 110 normals progressed to normal tension glaucoma (NTG). The relative risk of progression amongst OHT was 19.1 (95% CI: 2.2-163.4). All those who progressed had bilateral OHT. The mean and peak IOP in those who progressed was 25.4 mm Hg and 29.3 mm Hg compared to 23.9 mm Hg and 25.7 mm Hg in those who did not. Those who progressed had more than 8 mm Hg diurnal variation. The diurnal variation was less than 6 mm Hg in those who did not progress. No patient developed blindness due to glaucoma. CONCLUSION: The 5-year incidence of POAG amongst OHT in this population was 17.4% (3.5% per year). Bilateral OHT, higher peak IOP and large diurnal variation may be the risk factors for progression.

Comparison between latanoprost and brimonidine efficacy and safety in Indian eyes.

PURPOSE: To compare the short-term efficacy and safety of topical latanoprost and brimonidine in Indian eyes. MATERIALS AND METHODS: Twenty-eight patients with ocular hypertension, primary open-angle, pseudoexfoliation or pigmentary glaucoma were enrolled. Following baseline measurements, latanoprost was applied topically once daily in the evening for 12-weeks. After a washout period, brimonidine was applied twice daily in all patients for 6 weeks; 16 patients continued for 12 weeks. Patients were examined at 2, 6 and 12 weeks. The primary outcome measure was the difference in mean intra ocular pressure (IOP) reduction at 6 and 12 weeks. The mean diurnal variation of IOP at baseline and at 12 weeks was also compared. RESULTS: Twenty-six of 28 enrolled patients completed the study. One randomly selected eye of each patient was used for analysis. At 6 weeks, the mean IOP reduction was 11.2 mm Hg (+/- 2.9 mmHg) with latanoprost and 6 mmHg (+/- 3.3 mmHg) with brimonidine. At 12 weeks this was 10.8 mmHg (+/- 2.8 mmHg) and 6.9 mmHg (+/- 3.1 mmHg) respectively. At 6 weeks 85.7% (24) eyes obtained more than 25% reduction in IOP with latanoprost compared to 13 (46.4%) with brimonidine. IOP reduction was maintained with both drugs throughout the study period. Two eyes did not show any response to brimonidine. Latanoprost reduced the diurnal variation of IOP from 5.10 to 2.90 mmHg; brimonidine reduced it from 4.70 to 3.90 mmHg. Conjunctival hyperaemia was present in one patient on latanoprost and three patients on brimonidine. Two patients experienced drowsiness with brimonidine. Neither drug produced side effects necessitating withdrawal from the study. CONCLUSION: In this short-term study, both latanoprost and brimonidine effectively reduced IOP and stabilised the diurnal curve in Indian eyes. Latanoprost was more effective than brimonidine.

Visual field defects in non-functioning pituitary adenomas.

PURPOSE: To report the prevalence and pattern of visual field loss in non-functioning pituitary adenomas and to study the relationship between the tumour size and severity of field defects. METHODS: Ninety-three patients with histologically confirmed pituitary adenomas, non-functional on hormonal assessment, underwent a complete ophthalmic assessment and automated perimetry using the HFA 30-2 programme. Defects with quadrantanopic or hemianopic characteristics, defined using criteria on the threshold/pattern deviation plots were considered typical. Typical defects were graded as mild, moderate and severe. All other defects were considered atypical. A neuroradiologist measured tumour size on a CT or MRI Scan. The Chi-square test for trend was used to test association of tumour volume with severity of typical defects. RESULTS: Eighty-eight (94.6%) of the 93 patients had a field defect. Typical field defects were seen in 69 (74.2%) patients and atypical in 19 (20.4%). A severe typical defect involving at least 3 quadrants in one or both eyes was the most common (24 patients or 25.80%). All 31 patients (33.3%) with a tumour size greater than 20 cc had field defects. Severity of field defect increased with tumour volume (Chi-square test for trends significant p = 0.0096). CONCLUSIONS: Field defects occurred in 95% of patients with non-functioning pituitary macroadenoma. A severe visual field loss involving at least 3 quadrants in one or both eyes was the most common. 20% of patients had atypical field defects. Severity of field defects increased with tumour volume.

Medico-social dimensions of menopause: a cross-sectional study from rural south India.

BACKGROUND: The quality of life of the increasing ageing population is becoming an important issue in India. There are very little data on the effect of menopause on women, especially from rural India. METHOD: A population-based cross-sectional study was conducted on perceptions regarding menopause, prevalence of menopausal symptoms and association of family environmental factors with menopausal symptoms among 100 postmenopausal and 100 premenopausal rural women in south India. RESULTS: Fifty-seven per cent of postmenopausal women perceived menopause as convenient. Sixty-nine per cent of them complained of diminishing abilities after menopause. Twenty-three per cent felt that sexual life ends with the onset of menopause. Sixteen per cent reported that their husbands had become disinterested in them after menopause and I1% were apprehensive about the loss of femininity. A higher proportion of postmenopausal women reported hot flushes, night sweats, urge incontinence and other somatic symptoms as compared to premenopausal women. Fifty-four per cent of postmenopausal and 32% of premenopausal women were currently not sexually active. Fifty-nine per cent of postmenopausal and 38% of premenopausal women expressed loss of sexual desire and this difference was statistically significant. There was no significant association between menopause and depression. A poor perceived relationship within the family was shown to have a significant association with depression. There was a significant association between multiple somatic symptoms and menopause. CONCLUSION: A significantly higher proportion of postmenopausal women suffer from vasomotor symptoms, urge incontinence, loss of sexual desire and multiple somatic symptoms. They do not link these symptoms with menopause. Poor family environmental factors have a stronger association with depression than menopause. In view of these findings, it is important to determine the feasibility and impact of hormone replacement therapy in preventive health care in rural India.