Team:BGU Israel/Description
Our team is comprised of students from all over Israel. We all chose to move to Beer Sheva, which is the largest city in the Negev desert of southern Israel. Our idea started by thinking how to solve one of the problems we have in Israel, specifically in the Negev, and third world countries as well- sandflies that spread Leishmaniasis.
Sandflies, prevalent in many areas in Israel, are small mosquitoes that are the primary vectors of Leishmaniasis, a parasitic disease that can cause skin sores. Humans can get Leishmaniasis from the bite of the female sand-fly. The bite is painful and treatment of the disease is difficult, painful, and prolonged. The most common form of Leishmaniasis in Israel is cutaneous Leishmaniasis, which causes skin sores.
Our main goal was to interfere the parasite transmission by vector and not create a new vaccine/drug treatment to the parasite due to a high mutation and resistance rate. After further investigation about parasite transmission by vectors, we learned that additional parasites exist and are involved in the transmission of life-threatening diseases, such as Malaria, Zika fever, Dengue fever. Therefore, instead of focusing only on the Phlebotomus papatasi, the Leishmaniasis’ sand-fly, we thought to find a treatment for other vectors that will make an impact on the world’s population, especially in developing countries.
Due to technical and safety reasons, Leishmaniasis’ sand-fly is not suitable as a model for our project goal. Therefore, we sought for a different and safer model to set this project. We consulted with Dr. Ido Tzurim, an ecologist and a pest control specialist. He told us about the Bacillus thuringiensis subsp. israelensis (Bti) bacteria, which produces the Bti toxin and was found in Ben-Gurion University of the Negev (See photo below). The Bti toxin kills the larvae stage of mosquitos, but not the adult mosquitos. He suggested working on Aedes aegypti, which is a common mosquito world-wide, and a vector to deadly diseases, such as Zika fever, Dengue fever and the West Nile virus.
While many mosquito species lay eggs in large bodies of water, and can be easily exterminated, other mosquitos prefer to lay eggs in smaller, more hidden bodies of water, such as puddles and even ashtrays. This makes it more difficult to exterminate them, as it’s not possible to know where those hidden spots are, and therefore extermination in urban areas is more difficult. This led us to the question - how do we bring the Bti toxin to those hidden laying spots. The answer was simple - why not use the female mosquito as a trojan horse to lead the toxin to those laying spots? And that is how our project came to be - engineer transgenic bacteria that will naturally integrate into the adult mosquito’s microbiome and will be transferred to the mosquito’s offspring, therefore establishing a localized “plaque” in the egg-laying spots. This way, the adult mosquitos transmit the bacteria with the Bti toxin to their offspring that immediately die and will not develop to adults.
In 1976, Yoel Margalith discovered the Bti bacteria in our university, Ben-Gurion University of the Negev. Bti is a pathogenic bacterium to most mosquitos, which by the release of crystal toxins kills mosquito larvae.
In 2003, Margalith was awarded the very prestigious Tyler Prize for Environmental Achievement for this discovery.