Malaria vectors and transmission dynamics in coastal south-western Cameroon

Background

Malaria is a major public health problem in Cameroon. Unlike in the southern forested areas where the epidemiology of malaria has been better studied prior to the implementation of control activities, little is known about the distribution and role of anophelines in malaria transmission in the coastal areas.

Methods

A 12-month longitudinal entomological survey was conducted in Tiko, Limbe and Idenau from August 2001 to July 2002. Mosquitoes captured indoors on human volunteers were identified morphologically. Species of the Anopheles gambiae complex were identified using the polymerase chain reaction (PCR). Mosquito infectivity was detected by the enzyme-linked immunosorbent assay and PCR. Malariometric indices (plasmodic index, gametocytic index, parasite species prevalence) were determined in three age groups (<5 yrs, 5–15 yrs, >15 yrs) and followed-up once every three months.

Results

In all, 2,773 malaria vectors comprising Anopheles gambiae (78.2%), Anopheles funestus (17.4%) and Anopheles nili (7.4%) were captured. Anopheles melas was not anthropophagic. Anopheles gambiae had the highest infection rates. There were 287, 160 and 149 infective bites/person/year in Tiko, Limbe and Idenau, respectively. Anopheles gambiae accounted for 72.7%, An. funestus for 23% and An. nili for 4.3% of the transmission. The prevalence of malaria parasitaemia was 41.5% in children <5 years of age, 31.5% in those 5–15 years and 10.5% in those >15 years, and Plasmodium falciparum was the predominant parasite species.

Conclusion

Malaria transmission is perennial, rainfall dependent and An. melas does not contribute to transmission. These findings are important in the planning and implementation of malaria control activities in coastal Cameroon and West Africa.

     

GC/MS Profiling and Evaluation of Leaf Essential Oil for Bactericidal Effect and Free Radical Scavenging Activity of Plectranthus amboinicus (Lour.) Spreng Collected from Odisha,India

Plectranthus amboinicus (Lour.) Spreng, known as the Indian borage or Mexican mint, is one of the most documented species in the family Lamiaceae for its therapeutic and pharmaceutical values. It is found in the tropical and subtropical regions of the world. The leaf essential oil has immense medicinal benefits like treating illnesses of the skin and disorders like colds, asthma, constipation, headaches, coughs, and fevers. After analyzing earlier reports with regard to the quantity and quality of leaf oil yield, we discovered that the germplasm taken from Odisha is preferable to other germplasms. The objective of the present work is to evaluate the free radical scavenging activity and bactericidal effect of leaf essential oil (EO) of Plectranthus amboinicus (Lour.) Spreng collected from the state of Odisha, India. The hydro distillation technique has been used for essential oil extraction. Upon GC/MS analysis, approximately 57 compounds were identified with Carvacrol as the major compound (peak area=20.25 %), followed by p-thymol (peak area=20.17 %), o-cymene (peak area=19.41 %) and carene (peak area=15.89 %). On evaluation of free radical scavenging activity, it was recorded that the best value of inhibitory concentration, was for DPPH with IC₅₀=18.64 ppm and for H₂O₂ with IC₅₀=9.35 ppm. The EO showed efficient bactericidal effect against both gram positive (Mycobacterium smegmatis, Staphylococcus aureus, Enterococcus faecium) and gram negative (Escherichia coli, Vibrio cholerae, Klebsiella pneumoniae) bacteria studied through well diffusion method. Fumigatory action of the essential oil was found against M. smegmatis, the model organism for tuberculosis study. Alamar Blue assay, gave a result with MIC value for M. smegmatis i. e., 0.12 μg/ml and the MBC value of 0.12 μg/ml. Hence, P. amboinicus found in Odisha can be suggested as an elite variety and should be further investigated for efficient administration in drug formulation.     

Genome subtraction for novel target definition in Salmonella typhi

Large genomic sequencing projects of pathogens as well as human genome leads to immense genomic and proteomic data which would be very beneficial for the novel target identification in pathogens. Subtractive genomic approach is one of the most useful strategies helpful in identification of potential targets. The approach works by subtracting the genes or proteins homologous to both host and the pathogen and identify those set of gene or proteins which are essential for the pathogen and are exclusively present in the pathogen. Subtractive genomic approach is employed to identify novel target in salmonella typhi. The pathogen has 4718 proteins out of which 300 are found to be essential (“ indispensable to support cellular life”) in the pathogen with no human homolog. Metabolic pathway analyses of these 300 essential proteins revealed that 149 proteins are exclusively involved in several metabolic pathway of S. typhi. 8 metabolic pathways are found to be present exclusively in the pathogen comprising of 27 enzymes unique to the pathogen. Thus, these 27 proteins may serve as prospective drug targets. Sub-cellular localization prediction of the 300 essential proteins was done which reveals that 11 proteins lie on the outer membrane of the pathogen which could be probable vaccine candidates.     

Qualitative and Dynamical Analysis of a Bionomic Fishery Model with Prey Refuge

Acta Biotheoretica - Viruses are the simplest of pathogens, but possess sophisticated molecular mechanisms to manipulate host behavior, frequently utilizing molecular mimicry. Severe acute...     

Current trends in waste valorization

This paper presents the scientific breakthroughs made in bioprocess engineering and microbial biotechnology for the conversion of wastes into products with added value and/or biofuels. The significant results obtained in the emerging fields of hybrid electrosynthesis, the role of enzymes in the degradation of plastics, polyhydroxyalkanoate and 5-aminolevulinic acid production, fermentation technology and the application of molecular engineering tools to bioprocess technology are highlighted.