New malaria vaccine shows promise

[From the archives; originally published November 18, 2005]

Malaria is one of the world’s leading infectious killers. World-wide, almost 40% of the world’s population is at risk of acquiring this disease–many of them in poor countries with limited resources to control the disease. Each year, malaria causes 300-500 million infections, and up to 3 million deaths–about 5000 Africans die of the disease every day; one child succumbs every 30 seconds. Mosquito-borne, simple devices (such as mosquito nets over beds) have been shown to drastically decrease the incidence of disease. Though these only cost a few dollars each, many in developing countries lack the resources to purchase them. Additionally, evolution, as we often see, has caused both the parasites that cause the disease (one of four species of Plasmodium) and the mosquitoes that transmit it (Anopheles species) to become resistant to our efforts to stop them. The parasites have developed high levels of resistance to many of the anti-malarial drugs, and many insecticides are of little use in controlling the mosquito population due to a similar phenomenon.

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Emerging Disease and Zoonoses series

Part One: Introduction to Emerging Diseases and Zoonoses

Part Two: Introduction to Emerging Diseases and Zoonoses continued

Part Three: Bushmeat

Part Four: War and Disease

Part Five: Chikungunya

Part Six: Avian influenza

Part Seven: Reporting on emerging diseases

Part Eight: Disease and Domesticated Animals

Part Nine: The Emergence of Nipah Virus

Part Ten: Monkeypox

Part Eleven: Streptococcus suis

Part Twelve: Salmonella and fish

Part Thirteen: new swine influenza virus detected

Part Fourteen: dog flu strikes Wyoming.

Part Fifteen: Clostridium species.

Part Sixteen: The origins of HIV.

Part Seventeen: “Mad cow,” kuru, and prion incubation periods.

Part Eighteen: spread of H5N1 in Nigeria.

Part Nineteen: bats and emerging viruses.

Part Twenty: subclinical infections with avian influenza.

Part Twenty-one: West Nile virus outbreak…in Idaho squirrels?

Part Twenty-two: Popeye never warned you about this.

Part Twenty-three: Pets ain’t all they’re cracked up to be.

Part Twenty-four: Rift Valley Fever outbreak in Kenya.

Part Twenty-five: Rift Valley Fever update

Part Twenty-six: Chimps at risk of acquiring antibiotic-resistant infections

Part Twenty-seven: Rocky Mountain Spotted Fever.

Part Twenty-eight: Introduction to Marburg virus

Part Twenty-nine: Marburg virus: has the elusive reservoir species been found?

Part Thirty: swine flu in Ohio fairgoers?

Part Thirty-One: Newly discovered Ebola viruses: filling gaps in viral ecology

Part Thirty-Two: Chikungunya–in India, Italy, and Iowa

Part Thirty-Three: MRSA and swine: collision course

Part Thirty-Four: How far does religious freedom extend when it conflicts with public health?

Part Thirty-Five: What’s it like to work an Ebola outbreak?

Part Thirty-Six: Influenza meta-update: H5N1 spreading, new swine influenza virus found

Part Thirty-Seven: Where did syphilis come from?

Part Thirty-Eight: “One medicine, one health”

Part Thirty-Nine: What’s Google got to do with emerging disease?

Part Forty: Marburg hits Europe once again.

Part Forty-One: New Ebola subtype confirmed.

Part Forty-Two: Ebola in pigs!

Part Forty-Three: MRSA in US Swine

Part Forty-Four: Swine flu–a quick overview

Part Forty-Five: Swine flu and deaths in healthy adults–cytokine storm?

Part Forty-Six: Swine flu: 20 US cases now identified

Part Forty-Seven: Swine flu update: Europe and the bottom of the world

Part Forty-Eight: Swine flu–still spreading

Part Forty-Nine: Swine flu: Central & South America, Asia, New York update

Part Fifty: US up to 91 swine flu cases, including 1 death [Updated: New England confirmed cases]

Part Fifty-One: What does the WHO’s pandemic scale mean? And why is anyone worried about this?

Part Fifty-Two: Why I’ll be getting my kids their flu vaccines

Part Fifty-Three: MRSA and pets–should they get tested?

Part Fifty-Four: Staphylococcus aureus ST398 in a childcare worker

Part Fifty-Five: Staph in food–what does it mean?

Part Fifty-Six: MRSA and bedbugs–not so fast

Part Fifty-Seven: MRSA, Meat, and Motown

Part Fifty-Eight: Ebola in Uganda: current and past outbreaks

Part Fifty-Nine: Pigs with Ebola Zaire: a whole new can o’ worms

Part Sixty: When is MRSA not MRSA?

Part Sixty-One: E. coli O104:H4 in Europe–is it new?

Part Sixty-Two: E. coli update: sprouts as the culprit?

Part Sixty-Three: MRSA found in Iowa meat

Part Sixty-Four: Does bestiality increase your risk of penile cancer?

Part Sixty-Five: Castrating sheep with teeth–not a good idea (with video!)

Part Sixty-Six: MRSA in pork products–does the “antibiotic-free” label make a difference?

Part Sixty-Seven: The human origins of “pig” Staph ST398

Part Sixty-Eight: Influenza in bats

Part Sixty-Nine: The Emergence of Nodding Disease

Part Seventy: Poultry feather meal as a source of antibiotics in feed

Part Seventy-One: Ebola resurfaces in Uganda

Part Seventy-Two: Ebola: Back in the DRC

Related posts

Consumption of wild animals down in China

In the field

Pneumonic Plague outbreak

Also of interest: Infectious Animals, a National Geographic piece.

Dunk malaria day

Yesterday, as mentioned previously, was Dunk Malaria day. I’m on the road today in cold ‘n’ gloomy Atlanta so pardon the delay, but coturnix has a collection of posts here regarding the topic. Just spent much of the morning hearing about new strategies to control vectors (aimed mostly at dengue, but some ideas could extend to malaria as well) and learning about new malaria drugs (and resistance to old ones), so perhaps I’ll be able to put up an overview later in the week. I’m away until Friday, so blogging this week will likely be rather sporadic.

Mechanism of malaria “hide and seek” coming into view

Malaria is one of mankind’s oldest known killers, with descriptions of the disease dating back almost 5000 years. Each year, malaria causes 300-500 million infections, and up to 3 million deaths–about 5000 Africans die of the disease every day; one child succumbs every 30 seconds. The disease is caused by a number of species of the Plasmodium genus. (In humans, malaria is almost always caused by one of four species: Plasmodium vivax, Plasmodium ovale, Plasmodium falciparum, and Plasmodium malariae, with P. falciparum causing the most severe disease). Unlike many pathogens I discuss on here, Plasmodium is a protozoan–a eukaroyte with a nucleus, like you and I. It also has a very complex life cycle, going through different stages in its mosquito and vertebrate host. (I presented a short overview of this previously in this post on potential malarial vaccines). Though vaccines may be available in the future, prevention today is largely via control of the mosquito vectors using insecticides and mosquito netting. However, mosquitoes are growing increasingly resistant to the insecticides, and many people living in at-risk areas lack the financial means to purchase bed nets.

There are anti-malarial drugs to treat the patient once they’ve already been infected, but these, too, are losing their effectiveness due to parasite evolution. Additionally, a single infection does not confer life-long immunity. Not only can an individual be infected with different species of Plasmodium, but the parasite can switch the antigens it presents–the proteins on the parasite surface that the immune system recognizes. A recent study published in the journal Nature sheds some light on just how P. falciparum switches these antigens.
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