Researchers have made significant progress towards a new test that can be used to detect schistosomiasis, which could help the World Health Organization (WHO) reach its goal of stopping the transmission of the disease and eventually, eliminating it.
Schistosomiasis, which is transmitted by parasitic blood flukes, is common in subtropical and tropical areas.
This is a disease of poverty. There are effective treatments available, but it could be a serious health problem when drinking water that is contaminated or waterways result in repeat infections.
Dr Mark Pearson, Lead Researcher and Research Fellow, Australian Institute for Tropical Health and Medicine (AITHM), James Cook University
A staggering 200 million people are affected by the urogenital schistosomiasis. It is one of two forms of the disease. It can trigger both acute and chronic illnesses. It is associated with bladder cancer and is a risk factor for HIV infection, particularly for women.
Dr Pearson stated that a test must be sensitive enough to detect low-level parasites that can transmit the disease to others.
The team also wanted a test that is non-invasive and can be administered at point of care , by a health professional in the community, for instance – and deliver a quick result.
The focus of the research was on the proteins that the parasite, Schistosoma haematobium, produces while resident within the human body.
“Thanks to our collaborators at the University of California, who were able to put nearly 1,000 of these proteins on a chip that’s about twice the size of the SIM card in your phone We were able to work quite efficiently at identifying which proteins were the main antigens that are the main targets of antibody responses.” Dr. Pearson stated.
The fluke proteins were tested for antibodies in blood and urine samples that international collaborators had taken in previous studies in Gabon, Tanzania and Zimbabwe.
“Importantly they included samples from populations in which we know the infection level was low. This allowed us to test whether our proteins were recognized by antibodies from people suffering from mild infections as well as those with heavy infections,” Dr Pearson said.
The candidate proteins were also examined using ELISA (Enzyme linked immunosorbent assay). This test has been employed in the 1970s to detect antibodies.
Dr. Pearson stated that “Between high-tech chips and the old-school ELISA approach We narrowed our choices from 992 proteins, to just five candidates for lead that we picked as the two that had the most sensitive.”
The result is a point-of care test strip, not unlike the pregnancy test, which carries recombinant versions of the chosen proteins and can detect even low-intensity schistosomiasis.
Dr Pearson stated that “This is a perfect fit for us.” It works with serum – blood. We are optimistic about the next steps, which would be to improve it to be able to use it as urine tests.
“This was an international effort that involved researchers from all over Africa and Europe and also in Australia as well as the United States and Thailand. This is an important step in protecting vulnerable communities against a tiny parasite that can do a lot of damage.
Merck Global Health Institute and the Australian Trade and Investment Commission supported the research. The findings are published in The Lancet Microbe.
Pearson, M.S., and. (2021) Immunomics-guided discovery of serum and urine antibodies for diagnosing urogenital Schistosomiasis Biomarker identification study. The Lancet Microbe. doi.org/10.1016/S2666-5247(21)00150-6.
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