News » Chapter 21 Vector Borne and Other Diseases

A new malaria vaccine is 100% effective in first trials

Contributed by paustian on Aug 09, 2013 - 09:55 AM

In a first stage trial an new type of malaria vaccine, made from whole, irradiated sporozoites, has shown itself to be 100% effective. The vaccine, PfSPZ was developed by Sanaria and its lead researcher, Stephen Hoffman, a veteran malaria researcher. This work was encourages by research in the 1970s, showing that long-lived protection could be had by exposure to thousands of bites from irradiated, infectious mosquitoes. Taking this observation and making progress has been slow because it is very difficult to create the weakened sporozoites and make them safe enough to use in a vaccine.

  • The mosquitoes have to be raised in sterile conditions and fed blood infected with the sporozoites
  • Billions of parasites then had to be harvested from the salivary glands of mosquitoes
  • These then have to be carefully handled to pass strict vaccine standards

The initial trial was encouraging, 6 of 6 patients who were given 5 doses of the vaccine were immune to subsequent challenges with the live parasite. In the control group, 5 of 6 not given the vaccine developed malaria, as did 3 of the 9 in a group that only received four doses. Larger trials are now scheduled and the method of delivery of the vaccine may make wide-spread use difficult. The vaccine has to be given intravenously, instead of orally or subcutaneously; the method all modern vaccines use. With more research, maybe these issues can be overcome. In any case, this is a giant step forward in treating a disease that causes the most harm to the most people worldwide. 

Weakened Immune Systems lead to Increased Virulence of Malaria parasite

Contributed by rmcgee on Jul 24, 2013 - 03:17 PM

A recent Penn State experiment studied the effects of weak immune systems on the virulence and aggressiveness of a malaria parasite in mice. The study involved disabling a key immune molecule, CD4 receptors, with an antibody and then infecting these mice and a control group with an uncompromised immune system with the malaria parasite Plasmodium chabaudi. It lasted 21 weeks and each week, the parasite was taken from one mice and transferred to another previously uninfected mouse. They froze the samples biweekly to analyze aggressiveness and virulence.

A new antimalaria drug: less expensive, simple treatment, easy to produce

Contributed by paustian on May 22, 2013 - 07:29 PM

Malaria is the most important tropical disease in the world, with over 665,000 deaths worldwide, many of them in children. The malaria parasites, protozoa of the Plasmodium genus, are susceptible to a number of drugs, but have been becoming more resistant the drugs available for treatment. Professor Jonathan Vennerstrom of the University of Nebraska Medical Center College of Pharmacy and his team announce the development of Synriam (a synthetic trioxolane) that has many of the properties of artemisinin, but none of the downsides.

The paper describing the synthesis, toxicology, and effectiveness of this trioxolane is available in Nature. I found it was interesting that this paper was published in 2004, yet the clinical trials took 8 years to complete and bring this drug to market. It demonstrates how careful governments have to be with new drugs being introduced into the market.

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