Therapeutic Assessment of Chloroquine-Primaquine Combined Regimen in Adult Cohort of Plasmodium vivax Malaria from Primary Care Centres in Southwestern India.

BACKGROUND: Several reports of chloroquine treatment failure and resistance in Plasmodium vivax malaria from Southeast Asian countries have been published. Present study was undertaken to assess the efficacy of chloroquine-primaquine (CQ-PQ) combined regimen for the treatment of P. vivax malaria patients who were catered by the selected primary health centres (PHCs) of Udupi taluk, Udupi district, Karnataka, India. METHOD: Five PHCs were selected within Udupi taluk based on probability proportional to size. In-vivo therapeutic efficacy assessment of CQ (1500 mg over three days) plus PQ (210 mg over 14 days) regimen was carried out in accordance with the World Health Organization's protocol of 28 days follow-up among microscopically diagnosed monoinfection P. vivax cohort. RESULTS: In total, 161 participants were recruited in the study of which, 155 (96.3%) participants completed till day 28 follow-up, fully complied with the treatment regimen and showed adequate clinical and parasitological response. Loss to follow up was noted with 5 (3.1%) participants and non-compliance with treatment regimen occurred with one participant (0.6%). Glucose-6-phosphate dehydrogenase deficiency (G6PDd, <30% of normal mean activity) was noted among 5 (3.1%) participants and one of them did develop PQ induced dark-brown urination which subsided after PQ discontinuation. G6PDd patients were treated with PQ 45 mg/week for eight weeks while PQ was discontinued in one case with G6PD 1.4 U/g Hb due to complaint of reddish-brown coloured urine by 48 hours of PQ initiation. Nested polymerase chain reaction test revealed 45 (28%) cases as mixed (vivax and falciparum) malaria. CONCLUSIONS: The CQ-PQ combined regimen remains outstandingly effective to treat uncomplicated P. vivax malaria in Udupi taluk and thus it should continue as first line regimen. For all P. vivax cases, G6PD screening before PQ administration must be mandatory and made available in all PHCs.

Surmised total leucocyte counts miscalculate the parasite index of Plasmodium vivax malaria patients of tertiary and primary care settings in South-Western India.

BACKGROUND: For the calculation of parasite index (PI) by microscopy method, an assumed total leucocyte count (TLC) of 8,000/µL is used conventionally. However, due to obvious variation in the population and individual TLCs, use of 8,000/µL may result in either over/underestimation of the PI. METHODS: This study was aimed at ascertaining the utility of 8,000/µL TLC, as well as other assumed TLCs, with respect to measured TLC for the calculation of PI. A tertiary care hospital and five primary health centres were the base for the prospective study conducted among microscopically proven, symptomatic Plasmodium vivax mono-infection patients aged ≥18 years. PIs calculated by assumed TLCs ranging from 4,000-11,000/µL were compared with those calculated by measured TLCs. Geometric mean with 95% confidence interval, Bland-Altman plot and Wilcoxon signed rank test were used for statistical analysis. RESULTS: A total of 284 P. vivax mono-infection patients, including 156 from a tertiary care hospital and 128 from five primary health centres, were recruited in the study. Assumed TLCs below 5,000 cell/µL and above 5,500 cell/µL in tertiary care setting resulted in significant (p <0.05) underestimation and overestimation, respectively. However, in primary health centres, it was an assumed TLC of 5,000 cell/µL, below and above which there was significant (p <0.05) underestimation and overestimation observed, respectively. CONCLUSIONS: Assumed TLC of 8,000/µL is not suitable for the calculation of PI. Either actual TLC of the patient should be measured or a representative TLC should be derived for the population under investigation for any study requiring calculated PI by microscopy.