New discovery to improve malaria elimination strategies

Date:
May 5, 2022
Source:
Walter and Eliza Hall Institute
Summary:
Researchers have made a crucial discovery about how asymptomatic
malaria infections impact the body, informing potential strategies
to control transmission and improve treatment outcomes.



FULL STORY ==========================================================================
WEHI researchers in Melbourne have made a crucial discovery about how asymptomatic malaria infections impact the body, informing potential
strategies to control transmission and improve treatment outcomes.


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The research team has shown that persistent, asymptomatic malaria
infections are not innocuous as previously believed. Instead, these
infections suppress the immune system, preventing it from eradicating
parasites from the bloodstream.

At a glance
* Researchers have discovered that asymptomatic malaria infections
are not
benign as previously thought.

* These asymptomatic infections suppress the immune system,
preventing the
body from taking full control of the malaria parasites.

* The findings encourage treatment of asymptomatic infection to stop
parasite transmission and increase the effectiveness of the
malaria vaccine.

The findings published in Molecular Systems Biology provide an alternative
view to the long-held belief that asymptomatic malaria infections are beneficial to help reduce the risk of severe disease, and suggest that
treating chronic infections could enhance vaccine effectiveness and
reduce transmission.

The study was led by WEHI PhD student Stephanie Studniberg and Associate Professor Diana Hansen in collaboration with researchers from Indonesia's Eijkman Institute for Molecular Biology, the Papuan Health and Community Foundation, and the Menzies School of Health Research at Charles Darwin University.

Is asymptomatic malaria a problem? Malaria remains one of the most
serious infectious diseases of humans with over 200 million clinical
cases and 600,000 deaths estimated in 2020.



==========================================================================
Some people can develop immunity to the malaria parasite Plasmodium
falciparum after many years of repeated infections. In these patients,
a small number of parasites continue to live silently in the bloodstream
but do not cause fever- like symptoms.

"These infections have historically been viewed as beneficial because
they were thought to offer protection against symptomatic disease,"
said Associate Professor Hansen.

"Based on this assumption, asymptomatic malaria is often left untreated
in countries where malaria is endemic, despite our poor understanding
of the real impact that these persistent infections have on people."
New studies report asymptomatic infections are responsible for up to
half of new transmissions, often sliding under the radar and sabotaging
efforts of malaria elimination programs.

Asymptomatic infections are not benign To investigate the real impact
of asymptomatic disease, the research team analysed the white blood
cells of patients carrying asymptomatic and symptomatic infections in
an endemic area of Indonesia.



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They found that patients with chronic asymptomatic malaria infections upregulated genes that suppressed the immune system, making more proteins
to help the parasites survive.

Associate Professor Hansen said that because the immune system is
suppressed and cannot work at full capacity, the body cannot take control
of the parasites and clear them from the bloodstream.

A new strategy to fight malaria Immunosuppression caused by asymptomatic malaria infections could have critical implications for the administration
of malaria vaccines and elimination strategies around the world.

"In an immunosuppressed individual carrying an asymptomatic malaria
infection, the effectiveness of the malaria vaccine is reduced as the
immune system does not have the capacity to be trained appropriately,"
said Associate Professor Hansen.

"If we were to treat individuals with asymptomatic malaria infections,
we would also reduce the invisible parasite reservoir that perpetuates transmission and deters efforts of malaria elimination campaigns."
The new information provides a framework to consider new polices
supporting screening and treatment of asymptomatic malaria in endemic
areas around the world.

The research was supported by the NHMRC, the Australian Academy of
Science, and the Ministry of Research and Technology of the Republic
of Indonesia.


========================================================================== Story Source: Materials provided by Walter_and_Eliza_Hall_Institute. Note: Content may be edited for style and length.


========================================================================== Journal Reference:
1. Stephanie I Studniberg, Lisa J Ioannidis, Retno A S Utami,
Leily Trianty,
Yang Liao, Waruni Abeysekera, Connie S N Li‐Wai‐Suen,
Halina M Pietrzak, Julie Healer, Agatha M Puspitasari, Dwi
Apriyanti, Farah Coutrier, Jeanne R Poespoprodjo, Enny Kenangalem,
Benediktus Andries, Pak Prayoga, Novita Sariyanti, Gordon K Smyth,
Alan F Cowman, Ric N Price, Rintis Noviyanti, Wei Shi, Alexandra
L Garnham, Diana S Hansen. Molecular profiling reveals features
of clinical immunity and immunosuppression in asymptomatic
P. falciparum malaria. Molecular Systems Biology, 2022; 18 (4)
DOI: 10.15252/msb.202110824 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2022/05/220505085627.htm

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