This study compared the predatory potential of nymphs of two dragonfly species viz. Crocothemis servilia (Drury, 1773) and Rhyothemis variegata (Linnaeus, 1763) using the different larval instars and pupae of Cx. quinquefasciatus (Say, 1823) as preys in normal laboratory settings. Field-collected fed and 24 h starved nymphs of C. servilia and R. variegata were offered 1^st, 2^nd, 3^rd and 4^th instar larvae and pupae of Cx. quinquefasciatus to monitor the rate of predation. A 24 h starved nymph of C. servilia showed the highest predation on the 2^nd instar larvae (92.00±4.06%) followed by the 3^rd (83.00±5.61%), 4^th (80±6.89%) and 1^st (76.00±4.85%) instar larvae and the pupae (26.00±2.91), respectively, whereas, that of R. variegata exhibited the highest consumption of the 1^st instar larvae (90.00±3.54 %) followed by the  2^nd (88.00±5.61 %), 3^rd (82.00±3.74 %), 4^th (70.00±7.91 %)  larval instar and the pupae (23.00±4.63), respectively within 24 h exposure. In the same period, the fed nymphs of C. servilia showed maximum consumption of the 2^nd instar larvae (77.00±3.54%) followed by the 3^rd (76.00±4.58%), 4^th (64.00±4.00%) and 1^st instar (55.00±3.53%) larvae and the pupae (24.00±3.67), respectively, whereas, that of R. variegata exhibited highest consumption of the 1^st instar larvae (67.00±5.38 %) followed by the 2^nd (65.00±10.12 %), 3^rd (58.00±8.46 %) and 4^th (53.00±4.06 %) instar larvae and the pupae (21.00±2.92), respectively. The rate of predation was significant on all the larval instars and the pupae compared to their control counterparts (p<0.05) and the starved larvae and nymphs of both the dragonfly species showed higher predation compared to the fed nymphs. The aforementioned findings suggest that nymphs of both of the dragonfly species exhibited considerable predation potential against the immature stages of the Cx. quinquefasciatus mosquito. The present study recommends assessing the feasibility of using these species in large-scale mosquito control programs.

Antibiotics are used for the treatment and control of diseases as well as a growth promoter in livestock production in Bangladesh. The frequent use of these antibiotics in veterinary practices may lead to residue and creates some potential problems not only in livestock but also in public health issues. The presence of residues of antibiotics in animal-derived foodstuffs may induce carcinogenic and mutagenic effects and leads to the condition of an allergic reaction, and the development of antibiotic resistance in human gut bacteria. Although misuse of antibiotics in human medicine is the principal cause of the problems, some antibiotic-resistant bacteria originating in animals may also be the contributory factors to the resistance. However, some of the antibiotic resistance problems can be attributed to the transfer of resistant bacteria from animals to humans and resistance genes from animal pathogens and commensal bacteria to human pathogens. Even though the antibiotics and their residues in feed and food products of animal origin cause serious public health problems but little is known by society due to the lack of proper information. So, this is important to review the uses of antibiotics in food animals and insight their public health significance in Bangladesh. However, the safety levels of animal feeds and food of animal origin must be strictly observed and the antibiotics should be used in accordance with the labeled directions public awareness should be developed about the indiscriminate use of antibiotics in animals and their hazardous residual impacts on the human body. Therefore, the present review focuses on the aspects of antibiotic use in the livestock production of Bangladesh.

The present study was aimed to optimize an analytical method for the quantification of carbamate and organophosphorus insecticide residues using Liquid Chromatography tandem Mass Spectrometry (LC-MS/MS). A series of experiments were conducted to select the parent ion and precursor ion and based on these findings, the analytical method for the determination of carbamate and organophosphorus insecticide residues using LC-MS/MS was developed. The electrospray ionization (ESI) mode was used to develop the method.  The linearity of the developed analytical method was very good and it was 0.999 for carbaryl, while it was 0.998 for chlorpyrifos. The optimization of MS/MS parameters has been done properly for both of the selected pesticides through direct infusion of 100 ug/L pure analytical standard solutions.

Pesticide residues in different crops, including food grains and vegetables are burning issues in Bangladesh. Therefore, the present study was conducted to analyze organophosphorus pesticide residues in three popular vegetables (cauliflower, hyacinth bean and yard long bean) collected from five local markets of Narsingdi district of Bangladesh. The collected vegetable samples were extracted and cleaned up using Quick, Easy, Cheap, Effective, Rugged and Safe (QuEChERS) extraction technique and analyzed by Gas Chromatography (GC) equipped with Flame Thermionic Detector (FTD). A total of 45 vegetable samples were analyzed. Among the 15 analyzed samples of hyacinth bean, three samples (20 % of the total samples) contained pesticide residues above the EU-MRL and the remaining samples did not contain any detectable residues of the selected organophosphorus pesticides. In case of cauliflower, out of 15 analyzed samples, two samples (13% of the total number of samples) contained pesticide residues above the EU-MRL. In case of yard long bean, of the 15 analyzed samples, four samples (27% of the total number of samples) contained pesticide residues above the EU-MRLs. This study reveals the present status of pesticide residue contamination in the selected vegetables.