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Background & Objectives: Dengue is one of the major public health problems worldwide, transmitted mainly by Aedes aegypti and Ae. albopictus mosquitoes. Rapid urbanisation and industrialisation have led to an increase in vector population in Northeastern states of India. In 2013, Guwahati, the capital city of Assam, India experienced an outbreak of dengue. This study was undertaken with an objective to determine infection rates of dengue viruses (DENV) in both the established vectors present in this region., Methods: During the outbreak (2013), adults and larvae of both the vector species were collected from different container habitats found in case reporting areas and container index was also recorded. The mosquitoes were first pooled, homogenised and processed for NS1-ELISA. This was followed by RT-PCR of the mosquito pools., Results: Both Ae. aegypti and Ae. albopictus were found breeding in containers with container index in the range of 29.41 to 80%. Six pools of Ae. aegypti were found to be positive for NS1 antigen. RT-PCR assay revealed positivity in only the NS1-ELISA positive pools, exhibiting circulation of serotype DENV-2. Minimum infection rate of female and male Ae. aegypti was recorded as 10.87 and 11.03 respectively., Interpretation & Conclusion: This is the maiden report of detection of DENV in wild caught Ae. aegypti mosquitoes from Northeastern Region of India. The study also demonstrates the presence of transovarial transmission of dengue virus in this part of country. This information is useful in respect of both entomological as well as epidemiological point of view for taking appropriate vector control measures.

Background & Objectives: Antimalarial resistance in P. falciparum malaria parasite creates a serious obstacle in malaria control programme. Keeping this in mind, in the present study antifolate resistance associated point mutations in P. falciparum dihydrofolate reductase (Pfdhfr) and dihydropteroate synthetase (Pfdhps) genes among the field samples in Arunachal Pradesh were determined., Methods: Blood samples were collected from 145 suspected malaria patients/healthy control subjects in malarious areas of Lohit and Changlang districts of Arunachal Pradesh, India during January 2012 to December 2013., Results: In microscopic slide examination, 51.03% (74/145) were found malaria positive. Plasmodium falciparum mono-infection was observed in 62.16% (46/74) of total malaria positive cases. Polymerase chain reaction (PCR) was employed in all the P. falciparum positive samples for detection of 648 bp of Pfdhfr and 710 bp of Pfdhps genes. All the amplified products were analysed for detection of single nucleotide polymorphisms in dhfr and dhps genes. A total of four different genotypes of Pfdhfr gene were observed, of which double mutant allele ANRNI was mostly prevalent and it was found in 65.22% (30/46) cases. Likewise, four different haplotypes of Pfdhps gene were detected, of which triple mutant allele AGEAA shares 69.57% (32/46) followed by other haplotypes. In Pfdhfr-Pfdhps two locus mutations analysis, two isolates in Changlang district had shown quintuple mutant haplotype AIRNL-AGEAA, likely to be associated with treatment failure. The P. falciparum two locus dhfr-dhps haplotype (ANRNI-AGEAA) was observed in 56.52% (26/46) cases., Interpretation & Conclusion: Overall, high grade of sulphadoxine-pyrimethamine resistance associated genetic polymorphisms were observed among the P. falciparum parasite population in Arunachal Pradesh during the study period.

Background & Objectives: Resistance against partner drugs of artemisinin has been reported from different parts of India. The study aims to find out the single nucleotide polymorphisms in Plasmodium falciparum ATPase6 gene associated with artemisinin resistance., Methods: Blood samples were collected from 141 patients with P. falciparum monoinfection in malaria endemic zones of Assam and Arunachal Pradesh. A 645 bp portion of PfATPase6 gene was amplified and sequenced to determine the frequency of mutations associated with resistance to artemisinin., Results: Mutations at codon S769N, which have been proposed to confer artemisinin resistance, were not detected in our study samples. Instead of that a novel non-synonymous mutation (C-T) at 1847 bp position resulting in serine to phenylalanine alteration at codon S616F was detected from the P. falciparum field isolates in Changlang district of Arunachal Pradesh, whereas no mutation was detected in any of the analyzed samples in Assam indicating that wild type PfATPase6 genotype was found circulating in this region. Overall, based on the mutational pattern, two haplotypes of PfATPase6 gene were observed during the study, the wild type and mutant S616F allele. The overall haplotype diversity (Hd) was found to be: 0.069 and nucleotide diversity (per site Pi): 0.00012. Highest haplotype diversity was recorded in Changlang district of Arunachal Pradesh having Hd value of 0.33333 along with single polymorphic site and nucleotide diversity (Pi): 0.00060. A pair-wise fixation index (FST) value of 0.16667 indicates great genetic differentiation within the parasite population of Changlang district with the population of Karbi Anglong, Chirang, Tinsukia, Sivasagar, Jorhat, NC Hills, Lakhimpur, Golaghat and Dibrugarh districts of Assam and Lohit district of Arunachal Pradesh., Interpretation & Conclusion: A better understanding of the distribution of antimalarial drug resistance with malaria parasite may provide insight into some of the epidemiological determinants of the increasing case burden.