Monika Soni

Dengue Outbreak in a Hilly State of Arunachal Pradesh in Northeast India

Dengue has been reported from plains as well as hilly regions of India including some parts of Northeast India. In July-August 2012, outbreak of fever with unknown origin (FUO) indicative of Dengue was reported in Pasighat, East Siang district of Arunachal Pradesh (AP) state. Serum samples (n = 164) collected from patients from Health Training and Research Centre General Hospital, Pasighat, were tested for NS1 antigen and IgM antibodies. NS1-positive samples were analyzed by RT-PCR assay and entomological surveys were carried out. The majority of suspected cases reported NS1 antigen positivity. Females and young adults were mostly affected. The majority of the amplified NS1-positive samples showed Dengue serotype 3 infection. Aedes (Stegomyia) albopictus, known as semiurban breeding mosquitoes, was the only potential vector species identified from the affected areas of Pasighat which single handedly contributed to the outbreak. Thus, the present work identifies Dengue as an emerging arboviral infection in hilly state of AP along with a looming risk of its spread to neighbouring areas.

Genetic polymorphisms associated with sulphadoxine-pyrimethamine drug resistance among Plasmodium falciparum field isolates in malaria endemic areas of Assam.

Background: The emergence of antimalarial drug resistance malaria parasite is widespread in North eastern region of India. During January 2012-December 2013, we conducted active surveillance for detection of antifolate resistance-associated genetic polymorphisms in Plasmodium falciparum malaria parasite from different malaria endemic areas of Assam. Materials and Methods: A total of 281 field samples were collected from suspected malaria patients of which 106 malaria P. falciparum positive cases were detected in microscopic slide examination. A nested PCR was done for amplification of a 648 bp portion of the dhfr gene and 710 bp portion of the dhps gene. Results: Mutation analysis revealed existence of three different haplotypes of the P. falciparum dhfr gene of which ANRNI was highly prevalent (90%). Triple mutant haplotypes AIRNI (N51I + C59R + S108N) of the dhfr gene associated with pyrimethamine resistance were prevalent in Chirang district of Assam. Whereas, dhps mutation study revealed that triple mutant haplotype AGEAA (S436A + A437G + K540E) associated with Sulphadoxine resistance was found among 26% of P. falciparum field isolates. However, P. falciparum dhfr-dhps two locus mutation analysis showed that there were a total of nine dhfr-dhps genotypes. Conclusion: It was noticed that 93.62% (88/94) isolates had mutations in the sequences of both enzymes, which is an indication of prevalence of high grade of Sulphadoxine - pyrimethamine resistance in P. falciparum malaria parasites in Assam.

Prevalence of multiple drug-resistant Plasmodium falciparum malaria cases in Northeast India

Two numbers of Plasmodium falciparum field isolates from Gossingpara, Runikhata area in Chirang district of Assam had shown multiple mutations in Pfcrt-dhfr-dhps gene (up to seven mutations: One mutation in Pfcrt gene, three mutations in Pfdhfr gene and three mutations in Pfdhps gene). Similarly, two cases in Bat camp, Miao area under Changlang district of Arunachal Pradesh had shown a total of eight mutations, of which one mutation in Pfcrt gene, three mutations in Pfdhfr gene, three mutations in Pfdhps gene and one mutation in PfATPase6 gene. One case in 3 Miles, Miao area of Changlang district has shown mutations in Pfcrt(one mutation), Pfdhfr(four mutations) and Pfdhps(three mutations) gene. These results indicated that there is an existence of multiple mutant P. falciparum malaria cases in northeastern region of India.

Molecular typing and phylogeny of Wolbachia: A study from Assam, North-Eastern part of India

BACKGROUND Wolbachia are maternally inherited endosymbiotic alphaproteobacteria, infecting 40-75% of arthropod species. Knowledge on distribution of native strains infecting mosquito vectors from endemic regions is essential for successful implementation of vector control interventions utilizing potential strains of Wolbachia. Study identified various native strains of Wolbachia inhabiting different mosquito species from field and colonised conditions of Assam. The fly Drosophila melanogaster was also included in our study. METHODS Different mosquito species collected from field viz; Aedes albopictus, Aedes aegypti, Anopheles hyrcanus, Anopheles annularis, Culex vishnui, Toxorhynchites splendens, Armegeries obturbans and fly Drosophila melanogaster were included in the study. Anopheles stephensi and Culex quinquefasciatus were obtained from RMRC, Dibrugarh mosquito colony y for Wolbachia screening. DNA was extracted from these species, amplified using group specific wsp primers followed by sequencing and phylogenetic analysis. RESULTS Aedes albopictus from Dibrugarh, Tinsukia and Sivasagar district showed superinfection with A and B group of Wolbachia but, Aedes albopictus from Tezpur district presented infection with A group only. Our study reports for the first time natural infection of Wolbachia A and B group from colonised Anopheles stephensi mosquito but reported no infection from field collected Anopheles hyrcanus or Anopheles annularis. Similarly Armigeres obturbans and Culex vishnui presented infection with only B group of Wolbachia. Drosophila melanogaster showed superinfection with A and B group. Toxorhynchites splendens, Aedes aegypti and Culex quinquefasciatus reported no infection with Wolbachia. CONCLUSION To the best of our knowledge this is the first study on Wolbachia screening from Northeast part of India and also first report of natural Wolbachia infection from colonised Anopheles stephensi species. The current understanding on distribution of Wolbachia strains naturally present within insect species from this geographical region should aid future Wolbachia mediated vector control strategies.