ABSTRACT
Prevention of re-establishment (POR) refers to the prevention of malaria outbreak/epidemic occurrence or preventing re-establishment of indigenous malaria in a malaria-free country. Understanding the effectiveness of the various strategies used for POR is, therefore, of vital importance to countries certified as "malaria-free" or to the countries to be thus certified in the near future. This review is based on extensive review of literature on both the POR strategies and elimination schemes of countries, (i) that have reached malaria-free status (e.g. Armenia, Mauritius, Sri Lanka), (ii) those that are reaching pre-elimination stage (e.g. South Korea), and (iii) countries at the control phase (e.g. India). History has clearly shown that poorly implemented POR programmes can result in deadly consequences (e.g. Sri Lanka); conversely, there are examples of robust POR programmes that have sustained malaria free status that can serve as examples to countries working toward elimination. Countries awaiting malaria elimination status should pre-plan their POR strategies. Malaria-free countries face the risk of resurgence mostly due to imported malaria cases; thus, a robust passenger screening programme and cross border collaborations are crucial in a POR setting. In addition, sustained vigilance, and continued funding for the national anti-malarial campaign programme and for related research is of vital importance for POR. With distinct intrinsic potential for malaria in each country, tailor-made POR programmes are built through continuous and robust epidemiological and entomological surveillance, particularly in countries such as Sri Lanka with increased receptivity and vulnerability for malaria transmission. In summary, across all five countries under scrutiny, common strengths of the POR programmes are (i) a multipronged approach, (ii) strong passive, active, and activated passive case detection, (iii) Indoor residual spraying (IRS), and (iv) health education/awareness programmes.
Subject(s)
Disease Eradication , Disease Outbreaks , Malaria , Developing Countries , Disease Eradication/history , Disease Eradication/methods , Disease Outbreaks/history , Disease Outbreaks/prevention & control , Endemic Diseases/history , Endemic Diseases/prevention & control , Epidemiological Monitoring , History, 15th Century , History, 16th Century , History, 17th Century , History, 18th Century , History, 19th Century , History, 20th Century , History, 21st Century , History, Medieval , Humans , Malaria/epidemiology , Malaria/history , Malaria/prevention & control , RiskABSTRACT
The rat liver rhodanese (thiosulphate: cyanide sulfurtransferase EC 2.6.1.1) has been immobilized on polyacrylamide gels. The immobilized enzyme had a pH optimum of 7.4 and Km values of 3.25 mM and 1.12 mM for S2O3(2-) and KCN, respectively. The enzyme was competitively inhibited by NaNO2 and CH3COONa and noncompetitively by amyl-nitrite. A modulation of activity was observed in the presence of Ca2+, Zn2+, and Cu2+. The results are discussed in line with the detoxicating function of liver rhodanese.
Subject(s)
Anions/pharmacology , Cations/pharmacology , Enzymes, Immobilized/antagonists & inhibitors , Enzymes, Immobilized/drug effects , Thiosulfate Sulfurtransferase/antagonists & inhibitors , Thiosulfate Sulfurtransferase/drug effects , Acrylic Resins , Animals , Calcium/pharmacology , Enzymes, Immobilized/metabolism , Hydrogen-Ion Concentration , Kinetics , Male , Metals/pharmacology , Rats , Rats, Wistar , Thiosulfate Sulfurtransferase/metabolismABSTRACT
The emergence of strains of malaria vectors resistant to malathion in an area of Pakistan, and the continuing search for improved methods of control, necessitated the examination of alternative safe insecticides, with improved residual effects, for future use in the Malaria Control Programme in Pakistan. For these reasons, the effectiveness of pirimiphos-methyl, as Actellic 25 WP, was evaluated on a large scale in one sub-sector of Sheikhupura district of Punjab Province near Lahore. Entomological and parasitological evaluations demonstrated that 1 g of pirimiphos-methyl/m2 was as effective as 2 g/m2. Vector mosquito densities were reduced to zero, or almost so, in all areas sprayed with pirimiphos-methyl, and only began to approach vector levels in unsprayed areas after 9-10 months. No new cases of malaria were detected in those areas sprayed with pirimiphos-methyl. Blood cholinesterase determinations after the application of the pirimiphos-methyl spray confirmed the absence of any toxic effect on the spray operators, nor were there any toxic symptoms in the house occupants.
Subject(s)
Insect Vectors , Insecticides , Malaria/prevention & control , Organothiophosphorus Compounds , Animals , Anopheles , Cholinesterases/blood , Environmental Exposure , Evaluation Studies as Topic , Housing , Humans , PakistanABSTRACT
A new in vitro dissolution test apparatus was designed and evaluated. Compressed tablets of drugs representing different solubility characteristics were tested at various air pressures and compared to dissolution patterns of similar tablets by the Levy beaker and USP methods. Air pressure of 46 mm generally was suitable for determining the dissolution rates of tablets. This new dissolution tester possibly can be useful in determining drug release from solid dosage forms and correlating it with in vivo bioavailability because dissolution rate can be controlled easily with the adjustment of air pressure without complicated changes in the apparatus, there is no excessive settling of particles, and complete drug dissolution can be achieved with no clogging of the screen.