A study on relapse/re-infection rate of Plasmodium vivax malaria and identification of the predominant genotypes of P. vivax in two endemic districts of Nepal

Abstract

BackgroundMalaria is a major public health problem in Nepal inflicted primarily by the parasite Plasmodium vivax, - the only species responsible for relapse cases in Nepal. Knowledge on its relapse rate is important for successful malaria control, but is lacking in Nepal. The information on circulating predominant genotypes of P. vivax is equally relevant for high endemic districts of Nepal to understand the transmission dynamics of the parasite and to uncover the coverage and efficacy of potential vaccine beforehand.MethodsA prospective observational study with a six months follow-up period was conducted from August 2010 to May 2011 in four health centres of Kailali and Kanchanpur districts of Nepal to access the relapse/re-infection rate of P. vivax. The prevalence and heterogeneity of its genotypes were identified by PCR-RFLP assay targeting central repeat region of circumsporozoite protein (Pvcsp).ResultsIn total, 137 cases microscopically suspected to have P. vivax infection were enrolled in the study. Of these, 23 cases (17%) were detected for the relapse/ re-infection-during a six-month period, with a high proportion being male cases of age group 11–20 years. For genotyping, 100 whole blood samples were analysed, of which 95% of the parasite isolates were found to be of VK210 genotype. The minor genotype VK247 existed either in isolation or as mixed infection with VK210 in rest of the samples.ConclusionsThe relapse/re-infection rate of 17% was determined for P. vivax in Kailali and Kanchanpur districts of Nepal. A heterogeneous Pvcsp genotypic distribution of P. vivax was detected with VK210 being a predominant type, suggesting a complex transmission dynamics of the parasite. Expanding such study in other endemic regions of Nepal would help provide a complete picture on relapse/re-infection rate and parasite genotypic variability that can help in effective control and management of malaria in Nepal.

Inequities in the use of sulphadoxine-pyrimethamine for malaria prophylaxis during pregnancy in Nigeria

“…Also, women residing in urban areas were more likely to use SP than those in the rural areas. The observed socioeconomic inequity in SP use in pregnancy compares well with Dialla et al study where income and wealth index had similar effects on the use of SP, but were interpreted as minor barriers when compared with provider factors such a stock-out of drugs 29 . Takem and colleagues, on the other hand, found that in Beua, Cameroon, socio economic status did not have any effect on the use of IPTp for malaria 30 .…”

“…While this may be the case for most regions, Onwujekwe et al reported that women attending ANC in private health facilities in South-east Nigeria were more likely to receive SP for malaria prophylaxis than those attending public facilities 16 . This could be associated with frequent stock-out of drugs which is commonly experienced in public health facilities and has been reported as one of the major factors affecting malaria interventions in Nigeria 29 , 35 – 36 . The timing of the first ANC visit and frequency of visits may well affect the use of SP for malaria prophylaxis in pregnancy 11 , and although Dialla et al reported that attaining the recommended number of ANC visits did not ensure that women received at least 2 doses of IPTp, the difference in sample size could explain this observed disparity 29 .…”

“…This could be associated with frequent stock-out of drugs which is commonly experienced in public health facilities and has been reported as one of the major factors affecting malaria interventions in Nigeria 29 , 35 – 36 . The timing of the first ANC visit and frequency of visits may well affect the use of SP for malaria prophylaxis in pregnancy 11 , and although Dialla et al reported that attaining the recommended number of ANC visits did not ensure that women received at least 2 doses of IPTp, the difference in sample size could explain this observed disparity 29 . Overall, our findings corroborate reports of substantial missed opportunities for administering SP in pregnancy since a considerably larger proportion of women appear to be attending ANC than using SP for malaria prophylaxis in pregnancy 10 .…”

The Investment Case for Malaria Elimination in Thailand: A Cost–Benefit Analysis

“…Under both scenarios, 10% of Pf treatments were assumed to fail because of antimalarial resistance, 23 and 16.8% of Pv cases were assumed to relapse. 2, 24,25 We assumed a case fatality rate under the elimination scenario of 1.1 deaths per 1,000 cases based on 2012-2014 data. 2 Under resurgence, we assume that the health system would struggle to handle the increased case load, so this rate would increase to 2.0 deaths per 1,000 cases, which was the average case fatality rate in 2007 (P. Sudathip, personal communication).…”

Patterns and trends of malaria in 25 risk districts of Nepal from 2001 to 2017

“…From the aforementioned, Terai region is set as the higher (90%) risk for transmitting malaria [812]. However, only P. vivax and P. falciparum are detected as responsible protozoa for transmitting the disease [13141516]. Hence, gaining knowledge of mortality due to malarial disease can be beneficial in improving health policy, and thus improving the survival and extending the longevity.…”