Malaria is a vector-borne infectious disease, caused by five different species of the genus Plasmodium, and is endemic to many tropical and sub-tropical countries of the globe. At present, malaria diagnosis at the primary health care level in India is conducted by either microscopy or rapid diagnostic test (RDT). In recent years, molecular diagnosis (by PCR assay), has emerged as the most sensitive method for malaria diagnosis. India is highly endemic to malaria and shoulders the burden of two major malaria parasites, Plasmodium falciparum and P. vivax. Previous studies using PCR diagnostic assay had unraveled several interesting facts on distribution of malaria parasites in India. However, these studies had several limitations from small sample size to limited geographical areas of sampling. In order to mitigate these limitations, we have collected finger-prick blood samples from 2,333 malaria symptomatic individuals in nine states from 11 geographic locations, covering almost the entire malaria endemic regions of India and performed all the three diagnostic tests (microscopy, RDT and PCR assay) and also have conducted comparative assessment on the performance of the three diagnostic tests. Since PCR assay turned out to be highly sensitive (827 malaria positive cases) among the three types of tests, we have utilized data from PCR diagnostic assay for analyses and inferences. The results indicate varied distributional prevalence of P. vivax and P. falciparum according to locations in India, and also the mixed species infection due to these two species. The proportion of P. falciparum to P. vivax was found to be 49:51, and percentage of mixed species infections due to these two parasites was found to be 13% of total infections. Considering India is set for malaria elimination by 2030, the present malaria epidemiological information is of high importance.
Evolution and spread of malaria parasite Plasmodium falciparum capable of evading antimalarials are the prime concern to malaria control. The currently effective drug, artemisinin (ART), is under threat due to detection of ART-resistant P. falciparum parasites in the Southeast Asian countries. It has been shown that amino acid (AA) mutations at the P. falciparum Kelch13 (Pfk13) gene provide resistance to ART. Nigeria, a part of the Sub-Saharan Africa, is highly endemic to malaria, contributing quite significantly to malaria, and resistance to chloroquine (CQ) and sulfadoxine-pyrimethamine (SP) combination drugs has already been reported. Since artemisinin combined therapy (ACT) is the first-line drug for treatment of uncomplicated malaria in Nigeria and five amino acid mutations have been validated in the Pfk13 gene alongside with candidate mutations for ART resistance, we performed molecular surveillance for mutations (following PCR and DNA sequence analyses) in this gene from two southwestern states of Nigeria. Statistical analyses of DNA sequences were also performed following different evolutionary models. None of the different validated and candidate AA mutations of Pfk13 gene conferring resistance to ART could be detected in P. falciparum sampled in the two southwestern states of Nigeria. In addition, DNA sequencing and sequence analyses indicated neither evolutionary selection pressure on the Pfk13 gene nor association of mutations in Pfk13 gene with mutations of other three genes conferring resistance to CQ and SP. Therefore, based on the monomorphism at the Pfk13 gene and nonassociation of mutations of this gene with mutations in three other drug-resistant genes in malaria parasite P. falciparum, it can be proposed that malaria public health is not under immediate threat in southwestern Nigeria concerning ART resistance.
Malaria is a human health hazard in the tropical and subtropical zones of the globe and is poised to be eliminated by the year 2030. Despite a decrease in incidence in the past two decades, many endemic countries, including India, report cases regularly. The epidemiology of malaria in India is unique owing to several features of the Plasmodium parasites, Anopheles vectors, ecoepidemiological situations conducive to disease transmission, and susceptible humans living in rural and forested areas. Limitations in public health reach, and poor health-seeking behaviour of vulnerable populations living in hard-to-reach areas, add to the problem. We bring all of these factors together in a comprehensive framework and opine that, in spite of complexities, targeted elimination of malaria in India is achievable with planned programmatic approaches.
India is highly endemic to malaria with prevalence of all five species of human malaria parasites ofPlasmodiumgenus. India is set for malaria elimination by 2030. Since cases of mixedPlasmodiumspecies infections remain usually undetected but cause huge disease burden, in order to understand the distributional prevalence of both monospecies infections and mixed species infections in India, we collated published data on the differential infection incidences of the five different malaria parasites based on PCR diagnostic assay. About 11% of total cases were due to mixed species infection. Among several interesting observations on both single and mixed parasitic infections, incidences ofPlasmodium falciparummonoinfection were found to be significantly higher thanP. vivaxmonoinfection. Also,P. malariaeseems to be emerging as a potential malaria threat in India. Putting all the facts together, it appears that the dream of achieving malaria elimination in India will not be completely successful without dealing with mixed species infection.
25 September 2021 in Transactions of the Royal Society of Tropical Medicine and Hygiene
Problem: India and sub-Saharan Africa contributes about 85% of the global malaria burden, and India is committed to eliminating malaria by 2030. Approach: Two novel initiatives—the Malaria Elimination Demonstration Project (MEDP) in Madhya Pradesh and Durgama Anchalare Malaria Nirakaran (DAMaN) in Odisha—were initiated independently to demonstrate that indigenous malaria can be eliminated in a short period of time. Local setting: These initiatives focused on rural, tribal areas where there is a high malaria burden and complex epidemiology. Relevant changes: The case management and vector control strategies used in these programmes were based on the national guidelines, with context-specific changes and introduction of accountability at management, operational, technical and financial levels. The MEDP achieved a 91% reduction in malaria cases and recorded zero transmission for 6 consecutive and a total of 9 mo. The DAMaN project brought about an 88% reduction in malaria cases. Lessons learned: Malaria elimination will require robust surveillance and case management, monitoring of vector control interventions, community-centric information education communication and behaviour change communication initiatives and management controls, as well as regular internal and external reviews.
1 December 2018 in Infection, Genetics and Evolution