Malaria severity not determined solely by parasite levels in blood

May 7, 2014, NIH/National Institute of Allergy and Infectious Diseases

Although malaria kills some 600,000 African children each year, most cases of the mosquito-borne parasitic disease in children are mild. Repeated infection does generate some immunity, and episodes of severe malaria are unusual once a child reaches age 5. However, the relative contributions of such factors as the level of malaria-causing parasites in a person's blood—parasite density—to disease severity and to development of protective immunity are not well understood.

To clarify these issues, researchers from the United States and Tanzania regularly examined 882 Tanzanian beginning at birth and continuing for an average of two years. No simple relationship between parasite density and malaria severity emerged. For example, 253 children had a total of 444 infections characterized by high parasite density and mild symptoms. Of the 102 children who did develop severe malaria at least once while enrolled in the study, almost two-thirds (67) had high parasite density but only mild either before or after the episode of severe malaria.

Moreover, data from this study suggest that one or two mild episodes of malaria are not sufficient to eliminate the risk of severe malaria; a finding contrary to predictions made by some mathematical models. The researchers note that this prospective study is the first to provide direct evidence that risk is stable over several infections. The findings suggest a new approach to malaria vaccine development based on naturally acquired immunity. Such a vaccine would prevent severe disease and death in children, without necessarily reducing exposure to the .

The research team was led by Patrick E. Duffy, M.D., of the National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health.

Explore further: Cross-species malaria immunity induced by chemically attenuated parasites

More information: BP Gonçalves et al. Parasite burden and severity of malaria in Tanzanian children. NEJM DOI: 10.1056/NEJM 10.1056/NEJMoa1303944 (2014).

Related Stories

Cross-species malaria immunity induced by chemically attenuated parasites

July 1, 2013
Malaria, a mosquito-born infectious disease, kills over 600,000 people every year. Research has focused on the development of a vaccine to prevent the disease; however, many malaria vaccines targeting parasite antigens have ...

How the immune system prevents repeated malaria fever episodes in highly exposed children

April 17, 2014
Children in Mali (and many other regions where malaria is common) are infected with malaria parasites more than 100 times a year, but they get sick with malaria fever only a few times. To understand how the immune system ...

Austrian children injected with malaria parasite (Update)

May 2, 2014
An Austrian commission following up on claims that doctors deliberately infected patients with malaria to treat others with syphilis says hundreds of people, including orphans in a psychiatric hospital, might have been infected.

Viruses common complication in malaria patients

September 24, 2013
Scientists at the University of Liverpool have shown that viral brain infections may be a more important killer in African children than was previously thought.

Malaria's severity reset by mosquito

May 30, 2013
(Medical Xpress)—For the first time, researchers have proven that the way in which malaria is transmitted to the host affects how severe the resulting infection will be.

Proteomics discovers link between muscle damage and cerebral malaria

April 17, 2014
Malaria-related complications remain a major cause of death for children in many parts of the world. Why some children develop these complications while others don't is still not understood.

Recommended for you

New study offers insights on genetic indicators of COPD risk

January 16, 2018
Researchers have discovered that genetic variations in the anatomy of the lungs could serve as indicators to help identify people who have low, but stable, lung function early in life, and those who are particularly at risk ...

Previous influenza virus exposures enhance susceptibility in another influenza pandemic

January 16, 2018
While past exposure to influenza A viruses often builds immunity to similar, and sometimes different, strains of the virus, Canadian researchers are calling for more attention to exceptions to that rule.

Don't hold your nose and close your mouth when you sneeze, doctors warn

January 15, 2018
Pinching your nose while clamping your mouth shut to contain a forceful sneeze isn't a good idea, warn doctors in the journal BMJ Case Reports.

New antifungal provides hope in fight against superbugs

January 12, 2018
Microscopic yeast have been wreaking havoc in hospitals around the world—creeping into catheters, ventilator tubes, and IV lines—and causing deadly invasive infection. One culprit species, Candida auris, is resistant ...

Dengue takes low and slow approach to replication

January 11, 2018
A new study reveals how dengue virus manages to reproduce itself in an infected person without triggering the body's normal defenses. Duke researchers report that dengue pulls off this hoax by co-opting a specialized structure ...

Different strains of same bacteria trigger widely varying immune responses

January 11, 2018
Genetic differences between different strains of the same pathogenic bacterial species appear to result in widely varying immune system responses, according to new research published in PLOS Pathogens.

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.