Bees are among the most important species responsible for pollinating about one-third of the world's food reserves, and their contribution in the United States alone is estimated at 15-20 billion dollars a year. The rapid decline in honeybee colonies around the world, and especially in the United States, increased the burden on agricultural pollination and the future of food security. Parasites are one of the factors affecting the decline of the bee population, and Nosema ceranea and Nosema apis are among the most common. Nosema apis infection can have symptoms of dysentery and bowel movement at the entrance to the hive, but Nosema ceranae infection does not show any physical symptoms. This "silent killer" of honey bees infects worker bees, drones and queen bees and can even lead to the destruction of a colony.
Currently, the only approach to accurate diagnosis of this disease is the detection of spores of parasites using a light microscope. However, this traditional testing is conducted under laboratory conditions and requires expert work. Therefore, the beekeeper must send local samples to a remote laboratory for accurate diagnosis, which is time consuming and expensive.
Researchers at the University of California's Celli School of Engineering, in collaboration with the Department of Biology at Barnard College, developed a mobile microscope that allows you to quickly and automatically detect nozema spores in honey bees in the field. This mobile and cost-effective platform weighs only 0.8 pounds and consists of a smartphone-based fluorescence microscope, a specially developed application for a smartphone and an easy-to-use sample preparation protocol that allows you to mark the fluorescence of a bee parasite spores even in the field.
Aidogan Ozcan, a professor of electrical engineering and computing at the University of California at Los Angeles and deputy director of the California Institute of Nanosystems at the University of California at Los Angeles, led research in collaboration with Jonathan Snow, associate professor at the Department of Biology at Barnard College (New York) and Hatice Seylan Koydemir, Senior Researcher at the University of California. The study was published in Lab on chip, Journal of the Royal Society of Chemistry (UK).
Diagnosis of diseases using this new platform involves sample preparation, in which the intestinal tissue of honeybees is removed and the midgut is dissected, and then a small amount of spots is added to the fluorescent label of the parasite spores. Then a drop of the prepared solution is placed on a glass slide, which is then placed in a mobile microscope for analysis. The sample image is then captured by the smartphone and transferred to the computer for automatic analysis, in order to quickly identify the number of disputes that is sent back to the user in less than 90 seconds.
The researchers tested the performance of this mobile platform using field samples and determined that the device is able to determine the concentration of the parasite on the bee, which is below the threshold value required to recommend the treatment of Nosema parasites. Consequently, this device based on a mobile phone corresponds to the required detection sensitivity for establishing treatment.
“Ensuring the well-being of bees is a very important issue for global food security and ecosystem stability. There are many factors that influence the rapid decline in the number of bees, and parasitic infections play a significant role. The developed mobile device paves the way for solving this emerging problem in an inexpensive way, and as far as we know, this is the first and only existing portable platform for detecting Nosema spores in the field. ” said Ozkan.
The study was supported by the North American Pollinator Protection Campaign, the National Science Foundation's (ERC) Engineering Research Center, and the Howard Hughes Medical Institute (HHMI).
A tiny parasite can help reduce honeybee colonies by infecting larvae.
Jonathan V. Snow et al. Fast visualization, detection and quantification of Nosema ceranae spores in honey bees using fluorescence microscopy on a mobile phone, Lab on chip (2019). DOI: 10.1039 / C8LC01342J