Tuesday, July 20, 2010

The Fight Against Malaria – Some Encouraging News

Malaria continues to be a scourge in many parts of the world. The problem is particularly acute in Africa. Malaria is a pervasive illness characterized by high fevers, shaking chills, flu-like symptoms, and anemia. It is caused by a parasite referred to as Plasmodium falciparum (the Asian variety is Plasmodium vivax and not as virulent). Plasmodium is carried by the Anopheles mosquito prevalent in the tropics.

The plasmodium parasite exhibits a number of stages in its life cycle. The disease progresses in the following way. Once an individual is infected, sporozoites migrate to the liver where they develop into merozoites. From there they enter the bloodstream and attack red blood cells. Within 48 to 72 hours the infected red blood cells breakdown releasing more parasites into the bloodstream.

Chloroquine is a commonly used drug against Malaria. However some strains of the anopheles mosquito have developed an immunity to this drug. In this case, quinidine or quinine plus doxycycline, tetracycline, or clindamycin; or atovaquone plus proguanil (Malarone); or mefloquine or artesunate; or the combination of pyrimethamine and sulfadoxine, are given instead.

Malaria is so pervasive that it is estimated that 300 to 500 million individuals contract the disease each year resulting in approximately 1 million deaths. This is a wholly unacceptable situation from a world health perspective.

In spite of this daunting reality, significant inroads have been made, especially in the area of prevention. Thanks in part to the mass infusion of resources from the Bill and Melinda Gates Foundation, insecticide-treated bed nets, indoor spraying of insecticides and a category of powerful drugs called artemisinin-based combination therapies (ACTs) have shown remarkably positive results in pilot studies. In addition, although many attempts at making a completely effective vaccine have failed, a vaccine that seems to be 50% effective in offering protection for the first 8 months is now under development. These efforts, taken together, offer significant hope that the spread of this horrific disease may be curtailed in not eventually eliminated.

Wednesday, July 7, 2010

Impact of Climate Change on Phytoplankton

There is an unambiguous relationship between increasing levels of carbon dioxide in the atmosphere as a direct result of human activity and the increasing acidification of the oceans. This results from a well known chemical principle that carbonic dioxide (CO2) when dissolved in water (H2O) forms carbonic acid (H2CO3). This acidification has been implicated in the destruction of coral.

In a recent report in the journal Science, Doctor D. Shi from the Department of Geosciences at Princeton University has established a correlation between increasing acidity in the oceans and increased stress on phytoplankton. Phytoplankton is a fundamental part of the food web in the world’s oceans and, therefore, plays a key role in the life of the oceans. In addition they account for one-half of all oxygen production as a result of photosynthesis on the planet.

Doctor Shi and his colleagues have shown that acidification of the ocean places stress on phytoplankton populations by impacting the bioavailability of Iron. Iron plays a pivotal role in the metabolism of these organisms. This particular consequence of the ever increasing level of atmospheric carbon dioxide is certainly a cause for concern.