In fight against dengue, a scientific breakthrough

GCU claims to have found a way to block transmission of dengue virus in humans

LAHORE: If Pakistani scientists are to be believed, they have found a way to block the transmission of dengue virus to humans. If true, this will be a huge breakthrough as every year thousands of people in Pakistan are infected by the mosquito-borne disease.

Dengue is a virus spread via the Aedes aegypti mosquito with about 100 million people afflicted by the disease annually in more than 100 tropical countries worldwide. It causes fevers, extreme headaches, and muscle and joint pains, and in extreme cases of dengue hemorrhagic fever might result in death as well.



While there are no specific treatments or vaccines yet, at best doctors can give their patients supportive care, such as painkillers and liquids to keep them hydrated. Scientists across the world are looking for new ways to control Aedes mosquitoes – and thus dengue transmission.

However, entomologists at Lahore’s Government College University (GCU) have claimed to have genetically modified the Aedes aegypti mosquito to block the transmission of dengue virus to humans.

According to a statement issued by the varsity, a team of GCU medical entomologists, led by Zoology Department’s ex-chairperson Prof Dr Nusrat Jahan, have used Wolbachia, a genus of bacteria, as a biological agent for the genetic modification of laboratory-reared Aedes aegypti mosquitoes. Wolbachia-based technique makes the mosquito incapable of carrying and transmitting dengue viruses.

Prof Jahan said the GCU conducted the research in collaboration with Dr Zhiyong Xi, a professor at Michigan State University and the director of Joint Centre of Vector Control for Tropical Diseases, and developed this technology in Pakistan.

“The research has good potential to completely eradicate dengue vectors and viruses from Pakistan, saving thousands of precious lives,” the GCU statement claimed.

When an infected female mosquito bites a person, the virus enters the blood stream with the mosquito’s saliva and anticoagulant. Aedes aegypti are smaller and quieter than the typical mosquitoes. They are more at home in urban settings than in the jungle.

Controlling and limiting Aedes habitats is difficult since they prefer living indoors. They can lay eggs in a single drop of water and enjoy feeding around ankles, biting as many as 20 people a day.

In August 2011, the Nature magazine published two Australian studies, showing the ability of Wolbachia pipientis bacteria in stopping the reproduction of dengue virus in mosquitoes. They went on to show the bacterium could rapidly spread through wild Aedes populations, suggesting it could be a viable control mechanism for dengue fever.



The team led by Scott O’Neill of Monash University in Melbourne, Australia showed the strain of Wolbachia, called wMel, interrupts pathogen transmission within the insect without causing severe physical effects to the insect itself, making it a more environmentally safe candidate for dengue fever control efforts.

In 2010, Sanofi Aventis began phase-III of clinical trials of its dengue vaccine; the last step in clinical development before a potential vaccine is submitted for review by regulatory authorities for market production.

Phase-III studies are being carried out in Mexico, Colombia, Honduras, Puerto Rico, Peru, Philippines, Vietnam, Singapore, Australia and Thailand.

Published in The Express Tribune, October 15^th, 2016.