Joseph k David

Chloroquine efficacy studies confirm drug susceptibility of Plasmodium vivax in Chennai, India.

BackgroundAssessing the Plasmodium vivax burden in India is complicated by the potential threat of an emerging chloroquine (CQ) resistant parasite population from neighbouring countries in Southeast Asia. Chennai, the capital of Tamil Nadu and an urban setting for P. vivax in southern India, was selected as a sentinel site for investigating CQ efficacy and sensitivity in vivax malaria.MethodsCQ efficacy was evaluated with a 28-day in vivo therapeutic study, while CQ sensitivity was measured with an in vitro drug susceptibility assay. In both studies, isolates also underwent molecular genotyping to investigate correlations between parasite diversity and drug susceptibility to CQ. Molecular genotyping included sequencing a 604 base pair (bp) fragment of the P. vivax multidrug resistant gene-1 (Pvmdr1) for single nucleotide polymorphisms (SNPs) and also the amplification of eight microsatellite (MS) loci located across the genome on eight different chromosomes.ResultsIn the 28-day in vivo study (N=125), all subjects were aparasitaemic by Day 14. Passive case surveillance continuing beyond Day 28 in 22 subjects exposed 17 recurrent infections, which ranged from 44 to 148 days post-enrollment. Pvmdr1 sequencing of these recurrent infections revealed that 93.3% had identical mutant haplotypes (958M/Y976/1076L) to their baseline Day 0 infection. MS genotyping further revealed that nine infection pairs were related with ≥75% haplotype similarity (same allele at six or more loci). To test the impact of this mutation on CQ efficacy, an in vitro drug assay (N=68) was performed. No correlation between IC50 values and the percentage of ring-stage parasites prior to culture was observed (rsadj: -0.00063, p = 0.3307) and the distribution of alleles among the Pvmdr1 SNPs and MS haplotypes showed no significant associations with IC50 values.ConclusionsPlasmodium vivax was found to be susceptible to CQ drug treatment in both the in vivo therapeutic drug study and the in vitro drug assay. Though the mutant 1076L of Pvmdr1 was found in a majority of isolates tested, this single mutation did not associate with CQ resistance. MS haplotypes revealed strong heterogeneity in this population, indicating a low probability of reinfection with highly related haplotypes.

Diabetic retinopathy and its risk factors in patients with type 2 diabetes attending rural primary healthcare facilities in Tamil Nadu.

BACKGROUND India has a high burden of diabetic retinopathy ranging from 12.2% to 20.4% among patients with type 2 diabetes mellitus (T2DM). A T2DM management programme was initiated in the public sector in Tamil Nadu. We estimated the prevalence of diabetic retinopathy and its associated risk factors. METHODS We did a cross-sectional survey among patients with T2DM attending two primary health centres for treatment and follow-up in Kancheepuram, Tamil Nadu in January- March 2013. We did a questionnaire-based survey, and measured blood pressure and biochemical parameters (serum creatinine, plasma glucose, etc.) of the patients. We examined their eyes by direct and indirect ophthalmoscopy and defined diabetic retinopathy using a modified classification by Klein et al. We calculated the proportion and 95% CI for the prevalence and adjusted odds ratio (AOR) for risk factors associated with diabetic retinopathy. RESULTS Among the 270 patients, the mean (SD) age was 54.5 (10) years. The median duration of T2DM was 48 months. The prevalence of diabetic retinopathy was 29.6%. Overall, 65.9% of patients had hypertension, 14.4% had nephropathy (eGFR <60 mg/dl) and 67.4% had neuropathy. Among patients with comorbid conditions, 60%, 48%, 32%, and 3% were already diagnosed to have hypertension, neuropathy, retinopathy, and nephropathy, respectively. The risk factors for diabetic retinopathy were hypertension (AOR 3.2, 95% CI 1.7-6.3), duration of T2DM >5 years (AOR 6.5, 95% CI 3.6-11.7), poor glycaemic control (AOR 2.4, 95% CI 1.4-4.4), and nephropathy (AOR 2.3, 95% CI 1.1-4.6). CONCLUSIONS There was a high burden of undetected retinopathy and other comorbid conditions among patients with T2DM. Early detection of comorbid conditions and glycaemic control can be improved by training care-providers and educating patients.