BackgroundTriatoma rubrofasciata is the only kissing bug species distributed globally. In the Americas, this species transmits the parasite Trypanosoma cruzi, responsible for Chagas disease. The presence of T. rubrofasciata in several Asian countries has greatly increased recently. In Vietnam, it is found in large numbers, closely associated with human environments. Although T. rubrofasciata from Asia is not infected with Tryp. cruzi, it carries other parasites such as Trypanosoma lewisi and Trypanosoma conorhini. Reports of bites by T. rubrofasciata have increased significantly in several places of Vietnam, becoming a public health problem as it produces severe anaphylactic reactions.MethodsSpecimens of T. rubrofasciata were collected from seven provinces in central Vietnam. We analyzed different biological attributes (life-cycle, starvation resistance, feeding and reproductive capacities) and genetic characteristics (chromosomes and DNA sequences) of T. rubrofasciata from Vietnam and compared them with Brazilian specimens. Natural infection with Tryp. conorhini and Tryp. lewisi were analyzed in a sample of 100 collected insects.ResultsSpecies identification of T. rubrofasciata from central Vietnam was corroborated by genetic markers. Cytogenetic analyses showed that T. rubrofasciata from central Vietnam share the same chromosomal characteristics with individuals from Brazil and Hanoi. DNA sequence analyses of a mitochondrial cytochrome b gene fragment showed little variation between Old and New World specimens. Our study sample, compared with Brazilian individuals, showed a higher survival capacity revealed by a higher hatching rate (98% compared with 80.5%), a larger amount of blood taken in single meal and long-term starvation resistance. Furthermore, this species had a high natural rate of infection with Tryp. conorhini (46%) and Tryp. lewisi (27%).ConclusionsFor T. rubrofasciata of Vietnam, a high rate of fecundity throughout the year, a high capacity for starvation, and its occurrence in synanthropic environments of urban areas with a high availability of food sources are risk factors to be taken into account by vector control campaigns. The several allergic reactions caused by their bites and their high infection with Tryp. lewisi highlight the need to implement specific control programmes for T. rubrofasciata in Vietnam.
The cellular effects of platinum nanoparticles (PNP05, average size of 5 nm, and PNP30, average size of 30 nm) were investigated on murine leukemia Raw 264.7 cells. Cells treated with various concentrations of PNPs showed size-dependent cytotoxicity in an MTT assay with PNP5 of smaller nanoparticles higher toxicity than PNP30. Investigations on cell morphology, Annexin V assay, DNA fragmentation and the activity of caspase-3/-7 showed that PNPs induced apoptosis on Raw 264.7 cells by changing cell morphology and density, increasing cell population in apoptosis and causing nucleus fragmentation. Further study on caspase activity by Western blotting revealed that the apoptosis was induced by the activation of caspase-3 and -7. In addition, PNPs inactivated DNA repair system, generating dose-dependent DNA ladder bands on agarose gel electrophoresis. Taken together, PNPs triggered cytotoxicity on Raw 264.7 cells by suppressing cell growth/survival and inducing apoptosis.
Vietnam’s rapidly increasing leather and footwear export trade has made a significant contribution to the country’s economic development over recent years. However, the rapid growth of the leather industry causes considerable pollution, which poses increased risks to the environment and human health. A number of policies have been introduced by the government of Vietnam to mitigate the environmental pollution from the tanning industry. They include requirements for tanneries to (i) submit environmental impact assessment reports, (ii) install wastewater treatment systems, and (iii) pay wastewater fees. However, many tanneries in Vietnam did not comply with these regulations. This study aimed at investigating the compliance of Vietnam’s tanneries with environmental regulations and to explore policy recommendations for improving their compliance based on a survey of 54 tanneries in Hanoi, Quangnam and Hochiminh city. The results showed that medium-sized and large tanneries responded positively to environmental regulations while none of the small household tanneries surveyed were found to comply. The main reasons for the latter’s non-compliance were found to be the lack of technical and financial capacity. Nonetheless, the compliance rate of tanneries in general was found to be much higher than that of other industrial sectors in Vietnam. Inspections, production capacity, location of firms, and type of tannery were found to be significant factors affecting compliance. Raising the penalties for non-compliance, increasing monitoring activities to detect offenders, and employing a multi-stakeholder and collective action approach were seen as possible strategies to bring about the greening of the tanning industry.
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