Zika Diaries: Scientists discover that Zika-infected female mosquitoes can pass virus to their offspring
Adult female mosquitoes can pass the Zika virus along to their offspring, new research reveals.
Experts warn this means the virus will be much harder to control than previously thought.
The finding makes clear the need for pesticide programs that kill both adult mosquitoes and their eggs.
Current methods are not adequate, warns study co-author Dr Robert Tesh of the University of Texas.
The study published in the American Journal of Tropical Medicine and Hygiene concluded that the usage of larvicide is crucial in efforts to curb the spread of the disease.
Researchers from the University of Texas Medical Branch in Galveston injected lab-reared female Aedes aegypti mosquitoes with the virus. The researchers studied the culture of the adult offspring of these mosquitoes and found that on
e in every 290 mosquitoes was carrying the virus.“The ratio may sound low,” the study’s co-author Robert Tesh said in a statement, “but when you consider the number of Aedes aegypti in a tropical urban community, it is likely high enough to allow some virus to persist, even when infected adult mosquitoes are killed.”
Other viruses that pass on from the adult mosquitoes to their offspring include dengue and yellow fever. Both illnesses are transmitted by the same Aedes aegypti mosquito. The researchers found that vertical transmission helps the virus survive in inhospitable conditions like cold weather, dry spells and when people gain immunity to the virus due to prior infection or vaccination.
“Now we need to show that vertical transmission occurs in nature,” Tesh said. “Researchers need to collect larvae in areas where the virus is actively circulating — Latin America and the Caribbean, and now the Miami area. Finding infected larvae in an abandoned tire or water container would be evidence of vertical transmission.”
The World Health Organization declared Zika a global public health emergency in February. The virus is linked to severe birth defects and rarely results in death.
A total of 11,351 cases of Zika virus infection in the U.S. were confirmed by the Centers for Disease Control and Prevention. The first locally transmitted case of the virus was reported in Miami late July.
Tesh and the other researchers urge more insect studies while at the same time expanding methods to reduce the number of Aedes mosquitoes in and around homes to protect people from Zika virus infection. These steps include: removing standing water from containers and scrubbing them thoroughly to remove eggs and larvae; making sure that if water has to be stored in containers that they are tightly sealed to prevent mosquitoes from laying their eggs inside; and getting rid of trash such as old tires, plastic bottles and cups, and other objects in yards and vacant lots that can collect water and serve as mosquito breeding sites.
