Glutathione S transferases (GSTs) are multifunctional enzymes involved in detoxification of xenobiotic compounds in majority of the insect groups. Significance of insect GSTs is their elevated level of activity in association with insecticide resistance. This investigation was to explore the metabolic status of GSTs in two Indian DDT-resistant malaria vectors, Anopheles culicifacies and Anopheles annularis, and one DDT-susceptible vector, Anopheles fluviatilis. Malkangiri and Koraput districts of Orissa State, endemic for falciparum malaria and having a long insecticide spraying history, were the study areas. F1 progeny was raised from wild-caught females of the three vectors and used for biochemical assays to detect the GST-mediated DDT resistance mechanism. Results of the enzyme assay showed a significant 3-fold increase in GST activity in DDT-resistant An. annularis compared with its susceptible population. In DDT-resistant An. culicifacies, the median GST activity (71.8 micromol/min/mg) was almost the same as estimated in the DDT-resistant An. annularis (74.6 micromol/ min/mg), suggesting that the GST activity estimated in An. culicifacies could be an elevated level for detoxification of DDT. Furthermore, the GST activity in DDT-resistant An. culicifacies and An. annularis was significantly higher than that in the DDT-susceptible An. fluviatilis, which had a GST activity of 20.0 micromol/min/mg. Also, the GST-mediated DDT detoxification was confirmed by comparing GST activity in wild-caught females with that in their F1 progeny.

BACKGROUNDA severe outbreak of Japanese encephalitis (JE) and acute encephalitis syndrome (AES) with high case fatality was reported from Malkangiri district of Odisha state, India during September to November 2016 affecting 336 children with 103 deaths.OBJECTIVESThe purpose of this study was to investigate the outbreak in the light of entomological determinants.METHODSEntomological investigation was carried out in 48 villages from four mostly affected Community Health Centres (CHCs) of Malkangiri district. Dusk collections of resting adults was done in villages from indoor and outdoor sites to record the density of mosquito species, including the known JE vectors, feeding behaviour, parity, dusk index and infection status with JE virus (JEV).FINDINGSThe per man hour density and dusk index of JE vector species varied from 2.5 to 24.0 and 0.81 to 7.62, respectively in study villages. A total of 1136 mosquitoes belonging to six vector species were subjected to PCR and one pool of Culex vishnui was found to be positive for JEV.CONCLUSIONThe JE transmission in Malkangiri district was confirmed. Thorough screening of human blood samples of JE/AES suspected cases and JE vector mosquitoes for the presence of JEV during rainy season every year is recommended.

Neuroinflammation (inflammation in brain) has been known to play an important role in the development of dengue virus disease. Recently, studies from both clinical and experimental models suggest the involvement of neuroinflammation in dengue viral disease. Studies in clinical setup demonstrated that, microglial cells are actively involved in the patients having dengue virus infection, showing involvement of innate immune response in neuroinflammation. It was further proved that, clinical isolates of dengue-2 virus were able to initiate the pathologic response when injected in the mice brain. Natural killer cells were also found to play a crucial role to activate adaptive immune response. Notably, CXCL10/IFN-inducible protein 10 and CXCR3 are involved in dengue virus-mediated pathogenesis and play an important role in the development of dengue virus-mediated paralysis. In a latest report, it was seen that intracranial injection of dengue virus increases the CD8⁺ T-cell infiltration in brain, showing an important mechanism of neuroinflammation during the dengue virus infection. A similar study has described that, when DENV-3 is injected into the mice, it enhances the infiltration of CD8⁺ and CD4⁺ T cells as well as neutrophils. Cells immune-reactive against NS3 antigen were found throughout the brain. In conclusion, we focus on the various molecular mechanisms which contribute to the basic understanding about the role of neuroinflammation in dengue fever. These mechanisms will help in better understanding dengue pathophysiology and thus help in the development of possible therapeutics.

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