15 research outputs found
Cholera Outbreak Linked with Lack of Safe Water Supply Following a Tropical Cyclone in Pondicherry, India, 2012
In the aftermath of a severe cyclonic storm on 7 January 2012, a
cluster of acute diarrhoea cases was reported from two localities in
Pondicherry, Southern India. We investigated the outbreak to identify
causes and recommend control measures. We defined a case as occurrence
of diarrhoea of more than three loose stools per day with or without
vomiting in a resident of affected areas during 6-18 January 2012. We
used active (door-to-door survey) and stimulated passive (healthy
facility-based) surveillance to identify cases. We described the
outbreak by time, place, and person. We compared the case-patients with
up to three controls without any apparent signs and symptoms of
diarrhoea and matched for age, gender, and neighbourhood. We calculated
matched odds ratio (MOR), 95% confidence intervals (CI), and population
attributable fractions (PAF). We collected rectal swabs and water
samples for laboratory diagnosis and tested water samples for
microbiological quality. We identified 921 cases and one death among
8,367 residents (attack rate: 11%, case-fatality: 0.1%). The attack
rate was the highest among persons of 50 years and above (14%) and
females (12%). The outbreak started on 6 January and peaked on the 9th
and lasted till 14 January. Cases were clustered around two major
leakages in water supply system. Nine of the 16 stool samples yielded
V. cholerae O1 Ogawa. We identified that consumption of water from
the public distribution system (MOR=37, 95% CI 4.9-285, PAF: 97%),
drinking unboiled water (MOR=35, 95% CI 4.5-269, PAF: 97%), and a
common latrine used by two or more households (MOR=2.7, 95% CI 1.3-5.6)
were independently associated with cholera. Epidemiological evidence
suggested that this outbreak was due to ingestion of water contaminated
by drainage following rains during cyclone. We recommended repair of
the water supply lines, cleaning-up of the drains, handwashing, and
drinking of boiled water
A single weighting approach to analyze respondent-driven sampling data
Background and objectives: Respondent-driven sampling (RDS) is widely used to sample hidden populations and RDS data are analyzed using specially designed RDS analysis tool (RDSAT). RDSAT estimates parameters such as proportions. Analysis with RDSAT requires separate weight assignment for individual variables even in a single individual; hence, regression analysis is a problem. RDS-analyst is another advanced software that can perform three methods of estimates, namely, successive sampling method, RDS I and RDS II. All of these are in the process of refinement and need special skill to perform analysis. We propose a simple approach to analyze RDS data for comprehensive statistical analysis using any standard statistical software.
Methods: We proposed an approach (RDS-MOD - respondent driven sampling-modified) that determines a single normalized weight (similar to RDS II of Volz-Heckathorn) for each participant. This approach converts the RDS data into clustered data to account the pre-existing relationship between recruits and the recruiters. Further, Taylor's linearization method was proposed for calculating confidence intervals for the estimates. Generalized estimating equation approach was used for regression analysis and parameter estimates of different software were compared.
Results: The parameter estimates such as proportions obtained by our approach were matched with those from currently available special software for RDS data.
Interpretation & conclusions: The proposed weight was comparable to different weights generated by RDSAT. The estimates were comparable to that by RDS II approach. RDS-MOD provided an efficient and easy-to-use method of estimation and regression accounting inter-individual recruits' dependence
Occurrence of hepatitis B virus genotype B and B + C mixed infections in Chennai, South India
Median HRQoL scores by group.
<p>Each domain’s score was significantly different at 5% level (p<0.001).</p>*<p>Physical functioning; Role physical; Bodily pain & General health<sup>10.</sup></p>**<p>Role emotional; Social functioning; Vitality & Mental health<sup>10.</sup></p
HRQoL scores of clinically recovered C-CHIKV patients according to duration of disease free days (healthy days) at five months of follow-up.
<p>HRQoL scores of clinically recovered C-CHIKV patients according to duration of disease free days (healthy days) at five months of follow-up.</p
Signs and symptoms reported by C-CHIKV patients<sup>*</sup> according to clinical status.
*<p>Includes early and late symptoms experienced by the patients.</p
Socio-demographic and economic characteristics of study population.
<p>Socio-demographic and economic characteristics of study population.</p
Measles Case Fatality Rate in Bihar, India, 2011–12
<div><p>Background</p><p>Updated estimates of measles case fatality rates (CFR) are critical for monitoring progress towards measles elimination goals. India accounted for 36% of total measles deaths occurred globally in 2011. We conducted a retrospective cohort study to estimate measles CFR and identify the risk factors for measles death in Bihar–one of the north Indian states historically known for its low vaccination coverage.</p><p>Methods</p><p>We systematically selected 16 of the 31 laboratory-confirmed measles outbreaks occurring in Bihar during 1 October 2011 to 30 April 2012. All households of the villages/urban localities affected by these outbreaks were visited to identify measles cases and deaths. We calculated CFR and used multivariate analysis to identify risk factors for measles death.</p><p>Results</p><p>The survey found 3670 measles cases and 28 deaths (CFR: 0.78, 95% confidence interval: 0.47–1.30). CFR was higher among under-five children (1.22%) and children belonging to scheduled castes/tribes (SC/ST, 1.72%). On multivariate analysis, independent risk factors associated with measles death were age <5 years, SC/ST status and non-administration of vitamin A during illness. Outbreaks with longer interval between the occurrence of first case and notification of the outbreak also had a higher rate of deaths.</p><p>Conclusions</p><p>Measles CFR in Bihar was low. To further reduce case fatality, health authorities need to ensure that SC/ST are targeted by the immunization programme and that outbreak investigations target for vitamin A treatment of cases in high risk groups such as SC/ST and young children and ensure regular visits by health-workers in affected villages to administer vitamin A to new cases.</p></div