Malaria Elimination in the Greater Mekong Subregion: Challenges and Prospects

Malaria is a significant public health problem and impediment to socioeconomic development in countries of the Greater Mekong Subregion (GMS), which comprises Cambodia, China’s Yunnan Province, Lao People’s Democratic Republic, Myanmar, Thailand, and Vietnam. Over the past decade, intensified malaria control has greatly reduced the regional malaria burden. Driven by increasing political commitment, motivated by recent achievements in malaria control, and urged by the imminent threat of emerging artemisinin resistance, the GMS countries have endorsed a regional malaria elimination plan with a goal of eliminating malaria by 2030. However, this ambitious, but laudable, goal faces a daunting array of challenges and requires integrated strategies tailored to the region, which should be based on a mechanistic understanding of the human, parasite, and vector factors sustaining continued malaria transmission along international borders. Malaria epidemiology in the GMS is complex and rapidly evolving. Spatial heterogeneity requires targeted use of the limited resources. Border malaria accounts for continued malaria transmission and represents sources of parasite introduction through porous borders by highly mobile human populations. Asymptomatic infections constitute huge parasite reservoir requiring interventions in time and place to pave the way for malaria elimination. Of the two most predominant malaria parasites, Plasmodium falciparum and P. vivax, the prevalence of the latter is increasing in most member GMS countries. This parasite requires the use of 8-aminoquinoline drugs to prevent relapses from liver hypnozoites, but high prevalence of glucose-6-phosphate dehydrogenase deficiency in the endemic human populations makes it difficult to adopt this treatment regimen. The recent emergence of resistance to artemisinins and partner drugs in P. falciparum has raised both regional and global concerns, and elimination efforts are invariably prioritized against this parasite to avert spread. Moreover, the effectiveness of the two core vector control interventions—insecticide-treated nets and indoor residual spraying—has been declining due to insecticide resistance and increased outdoor biting activity of mosquito vectors. These technical challenges, though varying from country to country, require integrated approaches and better understanding of the malaria epidemiology enabling targeted control of the parasites and vectors. Understanding the mechanism and distribution of drug-resistant parasites will allow effective drug treatment and prevent, or slow down, the spread of drug resistance. Coordination among the GMS countries is essential to prevent parasite reintroduction across the international borders to achieve regional malaria elimination

Effect of seminal plasma removal, washing solutions, and centrifugation regimes on boer goat semen cryopreservation

Three experiments were carried out to improve semen quality during cryopreservation process. Total motility, forward motility, acrosome integrity, live spermatozoa, and normal spermatozoa were measured as semen quality. In Experiment 1, the effects of seminal plasma removal were analyzed by using two different extenders (GE and FE). The removal of seminal plasma gave higher and significant (P<0.05) effect in the total motility, forward motility, and live spermatozoa after cryopreservation. For two different extenders, however, the differences were not observed on the semen quality. In Experiment 2, three different washing solutions (namely, phosphate buffered saline, normal saline and Tris-based extender) were tested to evaluate the effects of semen quality after cryopreservation. Tris-based extender (TCG) conferred the highest (P<.05) sperm quality values in the total motility, forward motility, and live spermatozoa after cryopreservation. In Experiment 3, the effects of different centrifugation regimes (3000 × g for 3 min, 1600 × g for 10 min, 800 × g for 15 min) were evaluated on Boer semen quality. Semen quality parameters (namely, total motility, forward motility, acrosome integrity, and live spermatozoa) were significantly (P<.05) higher for cryopreserved spermatozoa centrifuged with 3000 × g for 3 min than the others. In conclusion, the removal of seminal plasma, washing solution TCG, and the use short-term centrifugation with a relative high g-force could contribute to the increased Boer semen quality after cryopreservation

Estimation on local transmission of malaria by serological approach under low transmission setting in Myanmar

Background: As the prevalence of the malaria has been decreasing in many endemic countries including Myanmar, malaria elimination in Greater Mekong Region was targeted not later than 2030. The relevance of molecular and serological tools to identify residual transmission remains to be established in this setting. Methods: One-year cohort study was conducted and sera samples were collected in every 3 months with active and passive case detection for clinical malaria episodes by RDT, microscopy and molecular method. The sera were used to detect the malaria antibody against PfMSP1-19, PvAMA1, PvDBPII and PvMSP1-19 by protein microarray. Results: Among the recruited 1182 participants, there was no RDT positive case for malaria infection although two vivax infections were detected by microscopy in initial collection. Molecular methods detected the asymptomatic cases of 28/1182 (2.37%) in first, 5/894 (0.42%) in second, 12/944 (1.02%) in third, 6/889 (0.51%) in fourth collection, respectively. Seropositivity rates against the PfMSP1-19, PvMSP1-19, PvAMA1 and PvDBPII were 73/270 (27.0%), 85/270 (31.5%), 65/270 (24.1%) and 160/270 (59.3%), respectively. PfMSP1-19 and PvMSP1-19 showed high and stable antigenicity in acute and subacute samples but declining in 1-year history samples. No cross reactivity of PfMSP1-19 and PvMSP1-19 between the two species and higher seropositivity among the asymptomatic carriers were observed. Mapping data indicated serological surveillance can detect the geographical pattern of malaria infection under low transmission setting. Conclusions: These findings support that PfMSP1-19 and PvMSP1-19 are suggested for serosurveillance of the malaria especially in low transmission setting for further necessary actions have to be carried out to eliminate the malaria.Publisher PDFPeer reviewe

Effect of sugars on characteristics of Boer goat semen after cryopreservation

In order to improve Boer goat semen quality during cryopreservation process, the influence of sugar supplementation on semen characteristics of sperm were investigated. Three experiments were carried out to investigate the effect of (a) addition of two monosaccharides (fructose and glucose) and two disaccharides sugars (trehalose and sucrose) (b) sugar combination (fructose and trehalose, sucrose and trehalose, glucose and trehalose), and control (glucose without trehalose) (c) different concentrations of trehalose on cryopreservation using Tris based extender. The total motility, forward motility, viability, normal spermatozoa, acrosome integrity and membrane integrity were assessed subjectively. Differences were not detected among monosaccharides, but glucose increased (P 0.05) among disaccharide sugar supplementation. Combination of glucose and trehalose significantly improved the characteristics of Boer spermatozoa after cryopreservation (P < 0.05). Supplementation of trehalose (198.24 mM) into the glucose extender significantly increased total motility, forward motility, live spermatozoa, acrosome integrity and membrane integrity following cryopreservation (P < 0.05). In conclusion, glucose had the better ability to support Boer sperm motility and movement patterns. Combination of monosaccharide (glucose) and disaccharide (trehalose) improved semen quality following cryopreservation. Trehalose supplementation at the concentration of 198.24 mM to the glucose extender conferred the greater improvement of semen quality for Boer semen cryopreservation

Efficient One Time Password Authentication Schme for Distributed Environment

In today's world of distributed environment, password authentication is very important to protect customer's sensitive data over Internet. The mainly two types of password are static password and dynamic password. Static passwords are highly susceptible to cracking, because passwords used will get cached on the hard drives. One Time Password (dynamic password) is a solution to solve the problems of static password. One Time Password is a password which changes every time the user logs in. Even if the attacker gets the password, it is useless to the attacker. This system is based on Lamport’s one time password scheme. Unlike Lamport’s scheme, new password initialization will depend on life-time and number of login (n) decided by Register Center. Diffie-Hellman Key Exchange Protocol will be used in this system for password initialization and the key exchange process of user’s password. This system will be developed in distributed environment with the aim of the users and servers’ mutual authentication

Time-stamp Oriented Efficient Secure Provenance Scheme

The amount of valuable information, which is stored and shared digitally on online and cloud computing, is dynamically increasing. So, the storage and sharing service providers must have the ability to identify the ownership and access history of each object for trustworthiness. The provenance is the most promising technology for this ability. Although the small numbers of researches have been done for secure provenance, they are weak in overhead and supporting integrity. So, this paper proposes the new secure provenance scheme to solve these weak points. In the proposed scheme, H (Dout) is created for data integrity and C and IToken are constructed for chain integrity. For chain integrity constructions, this scheme takes only the essential materials of previous and next provenance records instead of all other provenance records to reduce overhead. This scheme also provides the privacy (confidentiality) for user’s sensitive data using broadcast encryption with divisive clustering algorithm

New Hybrid Signcryption Approach: Efficient Digital Envelope Signcryption

In the study of Cryptography, the most important andwidely studied are confidentiality and integrity.Confidentiality is supported by encryption schemes,while integrity is provided by digital signature schemes.Drawback of symmetric encryption is key distributionproblem. Although asymmetric encryption can solve thisproblem, all of these ciphers are hundreds or thousandsof times slower than symmetric ciphers. Digitalenvelope combines the advantages of asymmetric andsymmetric key ciphers. It eliminates time complexityproblem of asymmetric encryption and key exchangeproblem of symmetric encryption. But it cannot providedata integrity. So it cannot be avoidable to use digitalsignature scheme to guarantee the source and integrity.New hybrid signcryption approach named “EfficientDigital Envelope Signcryption” is proposed. This newapproach operates digital signature process andasymmetric encryption process in a single step. It takesadvantages of digital envelope scheme and signcryptionscheme with appropriate algorithms

New Hybrid Signcryption Approach: Efficient Digital Envelope Signcryption

In the study of Cryptography, the most important and widely studied are confidentiality and integrity. Confidentiality is supported by encryption schemes, while integrity is provided by digital signature schemes. Drawback of symmetric encryption is key distribution problem. Although asymmetric encryption can solve this problem, all of these ciphers are hundreds or thousands of times slower than symmetric ciphers. Digital envelope combines the advantages of asymmetric and symmetric key ciphers. It eliminates time complexity problem of asymmetric encryption and key exchange problem of symmetric encryption. But it cannot provide data integrity. So it cannot be avoidable to use digital signature scheme to guarantee the source and integrity. New hybrid signcryption approach named “Efficient Digital Envelope Signcryption” is proposed. This new approach operates digital signature process and asymmetric encryption process in a single step. It takes advantages of digital envelope scheme and signcryption scheme with appropriate algorithms

Preparation and Structural Properties of Palm Shell

Bio-char can be produced by thermal conversion of biomass. Palm shells were obtained from palm fruits (palmira). They were air-dried to remove moisture. The dried palm shells were ground to become powder and heated at 600ºC, 800ºC and 1000ºC for 2 h respectively. After heating, bio-char was obtained. Structural properties of palm shell powder and bio-char were examined by X-ray diffraction (XRD). Scanning electron microscopy (SEM) was used to observe microstructure of biochar. Properties such as hydration capacity, pH were also evaluated