Reasons for increased resistance to anti-malaria drugs

The failure of the course of treatment to exert its expected effect on malaria infection may be reported from a health center, hospital or clinic following an abnormal increase in cases during subjunctive treatment. Resistance to anti malarial drugs is proving to be a challenging problem in malaria control in most parts of the world. For so many years now the sensitivity of the parasites to chloroquine declined and the drug is no longer a choice in treating malaria. New anti malarial drugs have been discovered in an effort to tackle this problem, but all these drugs are either expensive or have undesirable side effects. Drug resistance is the ability of the parasite species to survive and multiply despite the administration and absorption of a drug given in doses, equal to or higher than those usually recommended but within the limit of tolerance. The important factors that are associated with resistance are; Longer half-life (drugs that have a long expiration date), Single mutation for resistance, Poor compliance, host immunity and number of people using these drugs. The characteristics of a drug that make it vulnerable to the development of resistance are; a shallow concentration effect relationship and mutations that confer marked reduction in susceptibility. There is now circumstantial evidence, that the development of resistance can be delayed by combining a well matched drug pair; that is one drug that rapidly reduces parasite biomass combined with a partner drug that can remove any residual parasites. Drug resistance, has most commonly been seen in Palasmodium falciparum. Only few cases of resistance are reported with other types of malaria parasites such as the oval and vivax malaria. Resistance to chloroquine is most prevalent, while resistance to most other anti-malarials has also been reported. Chloroquine resistance has increased the usage of quinine. Quinine remains quite effective even after extensive use. Reports of resistance to quinine are rare, but have been reported in some areas and countries in the great lakes region. High degree of resistance to quinine is not common. For reasons not known clearly, it has been difficult to induce quinine resistance in experimental conditions. Efficacy of quinine can be increased by adding tetracycline group of drugs. Poor compliance is a major drawback of this drug. Most important to mention here is that the malaria parasite is highly sensitive to changes in temperature and even subtle warming can dramatically increase populations of the mosquitoes that transmit the disease. Warmer temperatures are at least partly to blame for a surge in malaria cases in the highlands of East Africa, and the increasing development of drug-resistant strains of the disease. Some scientists have argued that climate is not involved in the increasing highland epidemics. Instead, they say, adaptations in the parasite that make it resistant to anti-malarial drugs are the key drivers. Arguably by making conditions favourable for mosquitoes, we can see that warmer temperatures increase transmission, and therefore increase the number of people you treat. But sometimes there is a threshold at which treating more cases leads to a higher incidence of drug resistance, making the disease difficult to treat and contain. In many developing countries within Africa, malaria kills many people and outbreaks on the continent still continue. Climate change may also cause the disease to migrate away from low latitudes and this rids off outbreaks from some areas, but can affect other areas whose inhabitants have not developed any immunity. Human immunity is another important factor, especially among adults in areas of moderate or intense transmission conditions. Immunity is developed over years of exposure, and while it never gives complete protection, it does reduce the risk that malaria infection will cause severe disease. For this reason, most malaria deaths in Africa occur in young children, whereas in areas with less transmission and low immunity, all age groups are at risk. Ends