Nav: Home

Can crab shells provide a 'green' solution to malaria?

May 11, 2017

A non-toxic mixture of chitin-rich crab shell powder and nanosized silver particles could be an environmentally friendly way of curbing the spread of disease-carrying mosquitoes, and malaria in particular. This is according to a series of experiments led by Jiang-Shiou Hwang of the National Taiwan Ocean University. The findings are published in Springer's journal Hydrobiologia.

Mosquitoes carry diseases such as malaria, dengue fever, yellow fever, the Zika virus and encephalitis. Despite more than 100 years of research on the subject, malaria remains a global health problem, especially in Sub-Saharan Africa and Asia. In 2013, the number of malaria cases was estimated at 198 million, and the number of malaria-related deaths at 548 000. According to the World Health Organization, one child dies every minute from malaria in Africa. Products such as organophosphates, insect growth regulators, microbial control agents and organic solutions are used in efforts to control mosquito populations and the spread of the disease.

Hwang's team turned their attention to chitosan or chitin, a non-toxic natural substance that has been used in wound healing, as drug carriers and in manufacturing membrane water filters and biodegradable food package coating. Chitin is found in animal tissues, such as the exoskeletons of arthropods, bird beaks and insect eggs. It can easily be chemically changed, is quite strong and, because of its abundance in nature, is cost-effective to use.

The research team first crushed and oven-dried the exoskeletons of a number of hydrothermal vent crabs (Xenograpsus testudinatus) before extracting the chitin and other minerals. The subsequent creamy-white filtrate was then mixed with silver nitrate (AgNO3) to obtain a brown-yellow solution of silver nanoparticles (AgNP).

The solution was sprayed over six water reservoirs at the National Institute of Communicable Disease Centre in Coimbatore in India. Even in small concentrates it killed mosquito larvae and pupa quite effectively. It had the greatest effect during the early stages of the mosquito larvae's development.

The solution was also tested in conjunction with freshwater goldfish (Carassiu auratus) that fed on mosquito larvae. The nanoparticle solution did not have any effect on the fish, indicating that it is an environmentally friendly and non-toxic product. It also inhibited the growth of disease-causing bacterial species such as Bacillus subtilis, Escherichia coli, Klebsiella pneumoniae and Proteus vulgaris.

"This research highlighted that chitosan-fabricated silver nanoparticles are easy to produce, stable over time, and can be employed at low dosages to strongly reduce populations of the malaria vector, the Anopheles sundaicus mosquito, without detrimental effects on the predation of natural mosquito enemies, such as goldfishes," says Hwang. "It also effectively inhibits important bacterial pathogens."

Hwang hypothesizes that the nanosized particles pass through the insect cuticles and into individual cells to then interfere with various physiological processes that are part of a mosquito's life cycle.
-end-
Reference: Hwang, K.S. (et al). Chitosan-fabricated Ag nanoparticles and larvivorous fishes: a novel route to control the coastal malaria vector Anopheles sundaicus? Hydrobiologia DOI: 10.1007/s10750-017-3196-1

Springer

Related Malaria Articles:

Breakthrough in malaria research
An international scientific consortium led by the cell biologists Volker Heussler from the University of Bern and Oliver Billker from the Umeå University in Sweden has for the first time systematically investigated the genome of the malaria parasite Plasmodium throughout its life cycle in a large-scale experiment.
Scientists close in on malaria vaccine
Scientists have taken another big step forward towards developing a vaccine that's effective against the most severe forms of malaria.
New tool in fight against malaria
Modifying a class of molecules originally developed to treat the skin disease psoriasis could lead to a new malaria drug that is effective against malaria parasites resistant to currently available drugs.
Malaria expert warns of need for malaria drug to treat severe cases in US
The US each year sees more than 1,500 cases of malaria, and currently there is limited access to an intravenously administered (IV) drug needed for the more serious cases.
Monkey malaria breakthrough offers cure for relapsing malaria
A breakthrough in monkey malaria research by two University of Otago scientists could help scientists diagnose and treat a relapsing form of human malaria.
Getting to zero malaria cases in zanzibar
New research led by the Johns Hopkins Center for Communication Programs, Ifakara Health Institute and the Zanzibar Malaria Elimination Program suggests that a better understanding of human behavior at night -- when malaria mosquitoes are biting -- could be key to preventing lingering cases.
Widely used malaria treatment to prevent malaria in pregnant women
A global team of researchers, led by a research team at the Liverpool School of Tropical Medicine (LSTM), are calling for a review of drug-based strategies used to prevent malaria infections in pregnant women, in areas where there is widespread resistance to existing antimalarial medicines.
Protection against Malaria: A matter of balance
A balanced production of pro and anti-inflammatory cytokines at two years of age protects against clinical malaria in early childhood, according to a study led by ISGlobal, an institution supported by ''la Caixa'' Foundation.
The math of malaria
A new mathematical model for malaria shows how competition between parasite strains within a human host reduces the odds of drug resistance developing in a high-transmission setting.
Free malaria tests coupled with diagnosis-dependent vouchers for over-the-counter malaria treatment
Coupling free diagnostic tests for malaria with discounts on artemisinin combination therapy (ACT) when malaria is diagnosed can improve the rational use of ACTs and boost testing rates, according to a cluster-randomized trial published this week in PLOS Medicine by Wendy Prudhomme O'Meara of Duke University, USA, and colleagues.
More Malaria News and Malaria Current Events

Trending Science News

Current Coronavirus (COVID-19) News

Top Science Podcasts

We have hand picked the top science podcasts of 2020.
Now Playing: TED Radio Hour

Clint Smith
The killing of George Floyd by a police officer has sparked massive protests nationwide. This hour, writer and scholar Clint Smith reflects on this moment, through conversation, letters, and poetry.
Now Playing: Science for the People

#562 Superbug to Bedside
By now we're all good and scared about antibiotic resistance, one of the many things coming to get us all. But there's good news, sort of. News antibiotics are coming out! How do they get tested? What does that kind of a trial look like and how does it happen? Host Bethany Brookeshire talks with Matt McCarthy, author of "Superbugs: The Race to Stop an Epidemic", about the ins and outs of testing a new antibiotic in the hospital.
Now Playing: Radiolab

Dispatch 6: Strange Times
Covid has disrupted the most basic routines of our days and nights. But in the middle of a conversation about how to fight the virus, we find a place impervious to the stalled plans and frenetic demands of the outside world. It's a very different kind of front line, where urgent work means moving slow, and time is marked out in tiny pre-planned steps. Then, on a walk through the woods, we consider how the tempo of our lives affects our minds and discover how the beats of biology shape our bodies. This episode was produced with help from Molly Webster and Tracie Hunte. Support Radiolab today at Radiolab.org/donate.