Human Activities Near Lake Malaŵi Lead to Rise in Parasitic Infections
National Museum of Natural History scientist Bert Van Bocxlaer and an international team of researchers revealed that anthropogenic changes in Africa’s Lake Malaŵi are a driving force behind the increase of urogenital schistosomiasis, a debilitating tropical disease caused by parasitic flatworms.
Scientists estimate that 250 million people are affected by schistosomiasis worldwide, and 600 million more are at risk of contracting it. In some villages along the shorelines of Lake Malaŵi, 73 percent of the people and up to 94 percent of the schoolchildren are infected with urogenital schistosomiasis, one of several forms of the disease.
Van Bocxlaer’s research suggests that this spike in infection is directly linked to an increase in human populations and agricultural activities near Lake Malaŵi, and may include a change in the dietary preferences of mollusk-eating fishes. Details from this study and recommendations to reduce the prevalence of urogenital schistosomiasis are published in the May 2014 issue of Trends in Parasitology.
Human population densities in Malaŵi have more than doubled during the past 30 years, resulting in increased land use, overfishing and ecological changes that create a favorable environment for Bulinus nyassanus, a small freshwater snail that acts as an intermediate host of the disease-causing parasite.
Infected snails release larval flatworms that can penetrate human skin upon contact with water. Humans are the definitive host and, upon infection, excrete eggs that hatch in water and infect snails such as B. nyassanus.
“Scientists have long known that environmental changes can affect public health, but our research reveals that human impact on the environment plays a larger role in the spread of schistosomiasis than previously thought,” said Van Bocxlaer. “Decreasing the transmission of this infectious disease will require an integrated control program for schistosomiasis, including community-based health education with efforts toward more sustainable resource use.”
Van Bocxlaer and his team discovered that human activities surrounding Lake Malaŵi have led to drastic biotic and abiotic changes in the lake’s ecosystem. Observed changes include an increase in sedimentation and nutrient influx due to agricultural initiatives and soil erosion.
B. nyassanus thrives in the shallow, nutrient-rich sandy sediments along shorelines that humans frequent, and it faces few natural predators because populations of fish that feed on this snail have greatly declined due to overfishing. Scientists also suspect that the fish have a decreased affinity for eating B. nyassanus, favoring instead a recently introduced non-native form of the snail Melanoides tuberculata.
The research team examined sediment archives and compared historical and modern populations of B. nyassanus to determine ecological changes in Lake Malaŵi over time. The scientists relied on historical data, such as those preserved in museum collections, to determine that changes in snail populations in southern Malaŵi that, in conjunction with the impacts of human activities in this region, have contributed to an increase of schistosomiasis during the past several decades.
Symptoms of schistosomiasis generally originate in the urogenital organs and the intestines and can lead to life-threatening complications. Estimates from the World Health Organization suggest that more than 200,000 deaths per year are due to schistosomiasis in sub-Saharan Africa alone; approximately one-third of the total deaths caused by malaria worldwide.
Kathryn Sabella | Eurek Alert!
Laser activated gold pyramids could deliver drugs, DNA into cells without harm
24.03.2017 | Harvard John A. Paulson School of Engineering and Applied Sciences
What does congenital Zika syndrome look like?
24.03.2017 | University of California - San Diego
Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.
The results will be published on March 22 in the journal „Astronomy & Astrophysics“.
Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...
Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.
Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...
In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...
20.03.2017 | Event News
14.03.2017 | Event News
07.03.2017 | Event News
24.03.2017 | Materials Sciences
24.03.2017 | Physics and Astronomy
24.03.2017 | Physics and Astronomy