The Molecular Detection of Bacterial Infections of Public Health Importance in Hard Tick (Ixodidae) Nymphs Collected from the Forest Fringes of Western Ghats in the Goa, Karnataka and Maharashtra States of India

A survey was conducted to determine the human tick-borne bacterial infections in the nymphs which were collected from Western Ghats' fringe forest areas. Tick nymphs were collected using the flagging method from the villages where cases Kyasanur Forest Disease (KFD) were previously reported in the states of Goa, Karnataka and Maharashtra. A total of 200 tick pools consisting of 4587 nymphs were tested by PCR for the detection of bacteria of public health importance, such as Coxiella burnetii and Rickettsia spp. Of these, four pools (4.8%) in Karnataka and three pools (4.4%) in Maharashtra were positive for Coxiella burnetii, while none of the samples from Goa state were positive. Rickettsia spp. were positively obtained from Maharashtra (51.5%), Goa (35.42%) and Karnataka (26.19%). The sequence results of Rickettsia spp. showed similarity to the spotted fever group Candidatus Rickettsia shennongii, Rickettsia conorii subsp. heilongjiangensis and Rickettsia spp. strain koreansis. Individuals are entering into the forest areas for various reasons are more likely to infect with Coxiella burnetii. and Rickettsia spp.

Atorvastatin attenuates NS1 (Non-structural protein-1) of dengue type-2 serotype-induced expressions of matrix metalloproteinases in HL-60 cells, differentiated to neutrophils: Implications for the immunopathogenesis of dengue viral disease

BACKGROUND

The dengue is a vector borne viral infection in humans. Bite of mosquito infected with a dengue virus transmits the disease. The neutrophils support more to the innate immune response by switching to infected tissues and triggering immunomodulatory mechanisms including the release of proteases and host defence peptides.

METHODS

Cell viability by MTT and trypan blue dye exclusion assay, bright field microscopy for assessment of cell morphology, cytokines measurements by ELISA, estimation of protein by Bradford assay were done. Assessments of matrix metalloproteinase genes mRNA expressions were done using real-time PCR.

RESULTS

In the present study, we have for the first time unveiled that, NS1 antigen of dengue type-2 serotype, induce and stimulate the neutrophils cells to express high levels of matrix metalloproteases. NS1 exposure of HL-60 cells differentiated to neutrophils affected cell morphology and in 24 h of exposure. We have demonstrated that, the NS1 antigen has induced MMP-2, MMP-14 and MMP-9 expressions in neutrophils in a 24hrs exposure time. NS1 exposure has also further upregulated MMP-1, MMP-13, and MMP-8 expressions in neutrophils in a 24hrs exposure time. Notably, treatment with atorvastatin concentrations downregulated the expression profile of the all matrix metalloprotease significantly. Importantly, NS1 antigen has significantly increased the IL-6, IL-13 release by the HL,60 cells which was reversed by atorvastatin. On the other hand, NS1 exposure enhanced the mRNA expressions of VEGF-A and VEGF-D which was reversed by atorvastatin. However, we found that, NS1 exposure reduced the mRNA expressions profile of VEGF-C, which was reversed by atorvastatin.

CONCLUSION

In conclusion, we report that, neutrophils associated matrix metalloprotease are involved in the pathogenesis of dengue viral disease. VEGF growth factors may also be released by the neutrophils which may subsequently participate in the endothelial dysfunctions leading to dengue shock syndrome.

Nation-wide vector surveillance on Zika and Dengue did not indicate transmission of the American lineage-pandemic Zika virus in India

OBJECTIVES

Following the Public Health Emergency of International Concern declared on Zika by the World Health Organization during 2016, the Indian Council of Medical Research carried out nationwide vector surveillance for Zika and Dengue viruses (ZIKV and DENV) in India as a preparedness measure in 2016-19.

METHODS

High-risk zones distributed to 49 Districts in 14 states/union territories were included in the study. Seven ICMR institutions participated, following a standard operating protocol. Aedes specimens sampled weekly were processed by multiplex reverse transcriptase-polymerase chain reaction (RT-PCR) for ZIKV/DENV and random samples crosschecked with real-time RT-PCR for ZIKV.

RESULTS

Altogether, 79 492 Aedes specimens in 6492 pools were processed; 3 (0.05%) and 63 (0.97%) pools, respectively, were found positive for ZIKV and DENV. ZIKV infections were recorded in Aedes aegypti sampled during the 2018 sporadic Zika outbreak in Jaipur, Rajasthan. However, these belonged to the Asian lineage of the virus, already circulating in the country. Both Ae. aegypti and Aedes albopictus distributed to 8 states/union territories were found to be infected with DENV. Both sexes of Ae. albopictus were infected, indicating transovarial transmission.

CONCLUSION

This investigation evinced no active transmission of the American lineage-pandemic Zika virus in India during the pandemic period.

The Involvement of Neuroinflammation in Dengue Viral Disease: Importance of Innate and Adaptive Immunity

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.

Interaction affinity of Delta and Epsilon class glutathione-s-transferases (GSTs) to bind with DDT for detoxification and conferring resistance in Anopheles gambiae, a malaria vector

BACKGROUND & OBJECTIVES

The enzyme glutathione-s-transferases (GSTs) are associated with detoxification of DDT, as experimentally proved in Anopheles gambiae. Insect GSTs are classified into six classes and among them Delta and Epsilon class GSTs have been implicated in detoxification of organochlorine insecticides. Both Delta and Epsilon GSTs produce, in total, 24 transcripts that result in the production of corresponding enzyme proteins. However, the conventional assay estimates the level of total GSTs and relates to development of resistance to DDT. Hence, it would be more reliable to estimate the level of the specific class GSTs that shows higher affinity with DDT. This would also lead to design a specific molecular tool for resistance diagnosis.

METHODS

Of the 24 GSTs, computational models for 23 GSTs, which are available in Swiss-Prot database, were retrieved and for the remaining one, D7-2, for which no model is available in the data bank, a structural model was developed using the sequence of An. dirus B with a PDB ID of 1R5A as the template. All the models were docked with DDT in the presence of reduced glutathione.

RESULTS

The energy output showed that Delta, D6 has the highest interaction affinity with DDT. Hence, this particular GST (D6) is likely to get elevated on exposure of mosquitoes to DDT.

INTERPRETATION & CONCLUSION

It would be, therefore, possible to design a specific molecular assay to determine the expression level of such high affinity transcript(s) and to use for resistance diagnosis reliably in the vector surveillance programme.

Glutathione S transferase activity in Indian vectors of malaria: A defense mechanism against DDT

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.

Invasion of toxic marine cyanobacteria in to the tsunami affected coastal villages of southern India

This documentation explores the facts about the invasion of marine cyanobacteria in to the tsunami affected coastal villages of Nagapattinam district of Tamilnadu and Karaikkal district of Pondicherry Union Territory (UT) in southern India. Water samples were collected from eight tsunami-hit coastal villages in different open water sources. The collected samples were processed for detecting marine cyanobacterial growth. Totally 110 water samples were processed, three samples were positive for the toxic cyanobacteria, Lyngbya sp., and nine for nontoxic species such as Epithemia sp.,, Johannesbaptistia pellucida, Oscillatoria princeps, Phormidium fragile, Synechocystis sp. Besides posing a public health risk because of the toxic cyanobacteria, the bloom formation by the cyanobacterial species such as Anabaena, Microcystis, Lyngbya, Plectonema, Phormidium contaminated the water bodies and deteriorated the water quality in the tsunami affected villages. The study revealed that another kind of public health risk from the invasion of toxic cyanobacteria to the costal ecosystem during the tsunami. It is necessary, in this context, that the surveillance mechanism, which is geared up during or after natural disasters, should have a provision to monitor the transportation of toxic elements/organisms from marine system to coastal/inland ecosystems and to control such organisms.

In Silico analysis of voltage-gated sodium channel in relation to DDT resistance in vector mosquitoes

The voltage-gated sodium channel (VGSC) is the target site for insecticides such as DDT and synthetic pyrethroids. A single base (A-T) change in the knock-down resistance (kdr) allele leads to an amino acid substitution at position 267 that confers the target-mediated resistance to DDT and synthetic pyrethroids in Anopheles gambiae. A theoretical model of the VGSC domain II that contains the site of mutation was constructed using the K;+ channel protein of Aeropyrum pernix as a template. The validated model with 88.6% residues in the favored region was subjected to the CASTp program that predicted 30 pockets in the modeled domain II for ligand interaction. In the model, at position 267, leucine was manually replaced with phenylalanine. When this altered model was subjected to the CASTp program, the search results showed the same number of pockets. The docking results indicate that DDT interacts with the modeled VGSC domain II at position 275 in the presence of leucine or in the presence of phenylalanine (binding energy =-5.32 kcal/mol, -6.21 kcal/mol). It appears from the results that the mutation at position 267 has no direct influence on the interaction of DDT with the target protein. Therefore, to understand the interaction affinity of DDT with the target and influence of the mutation on the existence of active sites/pockets in relation to ligand binding, a whole VGSC model is necessary.

Hospital- and laboratory-based investigations of hospitalized children with central nervous system-related symptoms to assess Japanese encephalitis virus etiology in Cuddalore District, Tamil Nadu, India

A collaborative investigation of hospitalized encephalitic children in south India, between July 2002 and February 2003, has indicated that Japanese encephalitis was confirmed in 27.3% of these children. In developing countries, assessment of actual Japanese encephalitis disease burden requires strengthening of diagnostic laboratory capacities at hospitals.