Optimum Treatment Regimens for Helicobacter Pylori Infection

The treatment of Helicobacter pylori infection includes of current standard triple therapies consisting of a proton pump inhibitor, clarithromycin and amoxicillin or metronidazole on the basis of simplicity, safety, and efficacy. There are several factors determining the success of H. pylori eradication treatment. They include the components of a treatment regimen, the treatment duration, patient compliance, the presence of resistant or virulent strains of Helicobacter pylori and possibly the patient\u27s gastric acid secretory status. PPI, clarithromycin 500 mg, amoxicillin 1 g or metronidazol 400 mg, all given bid for 7 days are the most commonly used combination regimens. RBC-based triple therapies, furazolidone or rifabutin containing regimens can be used as an alternative approach to PPI-based triple therapies in areas where bacterial resistant strains of H. pylory are concerned

Vectorial status and insecticide resistance of Anopheles funestus from a sugar estate in southern Mozambique

<p>Abstract</p> <p>Background</p> <p>The dual problems of rising insecticide resistance in the malaria vectors and increasing human malaria cases since 2001 in southern Mozambique are cause for serious concern. The selection of insecticides for use in indoor residual spraying (IRS) programmes is highly dependent on the extent to which local mosquitoes are susceptible to the approved classes of insecticides. The insecticide resistance status and role in malaria transmission of <it>Anopheles funestus </it>was evaluated at the Maragra Sugar Estate in southern Mozambique where an IRS vector control programme has been in operation for seven years using the carbamate insecticide bendiocarb.</p> <p>Results</p> <p>No <it>Anopheles </it>species were captured inside the sugar estate control area. <it>Anopheles funestus </it>group captured outside of the estate represented 90% (n = 475) of the total collections. Of the specimens identified to species by PCR (n = 167), 95% were <it>An. funestus s.s. </it>One <it>An. rivulorum </it>was identified and seven specimens did not amplify. The <it>Anopheles gambiae </it>complex was less abundant (n = 53) and of those identified (n = 33) 76% were <it>An. arabiensis </it>and 24% <it>An. merus</it>. Insecticide susceptibility tests showed that wild-caught and F-1 family <it>An. funestus </it>were resistant to deltamethrin (32.5% mortality) and lambda-cyhalothrin (14.6% mortality), less so to bendiocarb (71.5% mortality) and fully susceptible to both malathion and DDT (100%). Bendiocarb and pyrethroid resistance was nullified using 4% piperonyl butoxide (Pbo), strongly suggesting that both are mediated by P450 monooxygenase detoxification. ELISA tests <it>of An. funestus </it>for <it>Plasmodium falciparum</it>, gave a sporozoite rate of 6.02% (n = 166). One unidentified member of the <it>An. gambiae </it>complex tested positive for <it>P. falciparum </it>sporozoites.</p> <p>Conclusion</p> <p><it>Anopheles funestus </it>was found to be the most abundant and principle vector of malaria in this area, with members of the <it>An. gambiae </it>complex being secondary vectors. Despite the continual use of bendiocarb within the estate for seven years and the level of <it>An. funestus </it>resistance to this insecticide, the IVC programme is still effective against this and other <it>Anopheles </it>in that no vectors were found inside the control area. However, the Mozambique National Malaria Control Programme ceased the use of DDT and bendiocarb in this area of its operations in 2009, and replaced these insecticides with a pyrethroid which will increase insecticide resistance selection pressure and impact on control programmes such as the Maragra IVC.</p

The impact of temperature on insecticide toxicity against the malaria vectors Anopheles arabiensis and Anopheles funestus

BACKGROUND: It is anticipated that malaria elimination efforts in Africa will be hampered by increasing resistance to the limited arsenal of insecticides approved for use in public health. However, insecticide susceptibility status of vector populations evaluated under standard insectary test conditions can give a false picture of the threat, as the thermal environment in which the insect and insecticide interact plays a significant role in insecticide toxicity. METHODS: The effect of temperature on the expression of the standard WHO insecticide resistance phenotype was examined using Anopheles arabiensis and Anopheles funestus strains: a susceptible strain and the derived resistant strain, selected in the laboratory for resistance to DDT or pyrethroids. The susceptibility of mosquitoes to the pyrethroid deltamethrin or the carbamate bendiocarb was assessed at 18, 25 or 30 degrees C. The ability of the pyrethroid synergist piperonyl-butoxide (PBO) to restore pyrethroid susceptibility was also assessed at these temperatures. RESULTS: Temperature impacted the toxicity of deltamethrin and bendiocarb. Although the resistant An. funestus strain was uniformly resistant to deltamethrin across temperatures, increasing temperature increased the resistance of the susceptible An. arabiensis strain. Against susceptible An. funestus and resistant An. arabiensis females, deltamethrin exposure at temperatures both lower and higher than standard insectary conditions increased mortality. PBO exposure completely restored deltamethrin susceptibility at all temperatures. Bendiocarb displayed a consistently positive temperature coefficient against both susceptible and resistant An. funestus strains, with survival increasing as temperature increased. CONCLUSIONS: Environmental temperature has a marked effect on the efficacy of insecticides used in public health against important African malaria vectors. Caution must be exercised when drawing conclusions about a chemical's efficacy from laboratory assays performed at only one temperature, as phenotypic resistance can vary significantly even over a temperature range that could be experienced by mosquitoes in the field during a single day. Similarly, it might be inappropriate to assume equal efficacy of a control tool over a geographic area where local conditions vary drastically. Additional studies into the effects of temperature on the efficacy of insecticide-based interventions under field conditions are warranted

A ceramographic evaluation of chromia refractories corroded by slag

This paper describes the ceramographic preparation of Cr{sub 2}O{sub 3}-Al{sub 2}O{sub 3} refractory bricks and subsequent microstructural analysis to determine the corrosive effects of molten slag. The porous and friable nature of the brick, especially after exposure to the slag or its individual components, presented some problems in the preparation

The Evolving Epidemiology of Helicobacter pylori

The relationship between Helicobacter pylori infection and the risk of gastric cancer has been well established in the last decade. Four metaanalyses have found that the infection increases the risk of noncardia gastric cancer by 2- to 6-fold compared with noninfected control populations. However, the role of cagA strains of H pylori in relation to gastric cancer has not been evaluated systematically. We undertook a meta-analysis of epidemiological studies examining the relationship between infection with cagA-positive strains of H pylori and the risk of gastric cancer, and found that patients who are seropositive for cagA strains of H pylori are at an increased risk for developing noncardia gastric cancer compared with those with H pylori infection alone. Therefore, searching for cagA-positive strains of H pylori may help identify populations at a greater risk for developing gastric cancer