Malaria severity not determined solely by parasite levels in blood

May 7, 2014

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

Co-infection with two common gut pathogens worsens malnutrition in mice

July 27, 2017
Two gut pathogens commonly found in malnourished children combine to worsen malnutrition and impair growth in laboratory mice, according to new research published in PLOS Pathogens.

Finish your antibiotics course? Maybe not, experts say

July 27, 2017
British disease experts on Thursday suggested doing away with the "incorrect" advice to always finish a course of antibiotics, saying the approach was fuelling the spread of drug resistance.

Phase 3 trial confirms superiority of tocilizumab to steroids for giant cell arteritis

July 26, 2017
A phase 3 clinical trial has confirmed that regular treatment with tocilizumab, an inhibitor of interleukin-6, successfully reduced both symptoms of and the need for high-dose steroid treatment for giant cell arteritis, the ...

A large-scale 'germ trap' solution for hospitals

July 26, 2017
When an infectious airborne illness strikes, some hospitals use negative pressure rooms to isolate and treat patients. These rooms use ventilation controls to keep germ-filled air contained rather than letting it circulate ...

Researchers report new system to study chronic hepatitis B

July 25, 2017
Scientists from Princeton University's Department of Molecular Biology have successfully tested a cell-culture system that will allow researchers to perform laboratory-based studies of long-term hepatitis B virus (HBV) infections. ...

Male hepatitis B patients suffer worse liver ailments, regardless of lifestyle

July 25, 2017
Why men with hepatitis B remain more than twice as likely to develop severe liver disease than women remains a mystery, even after a study led by a recent Drexel University graduate took lifestyle choices and environments ...

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.