If you’ve ever lived near a busy road, you’re familiar with the noise of cars whooshing by and ear-piercing honks. Traffic noise is a well-known source of stress in humans. Now, a team of researchers has found that it can cause increased stress levels in frogs too. And aside from a spike in stress, traffic noise can have other negative effects on the European tree frog (Hyla arborea), such as suppressed immunity and a dulling of males’ vocal sacs. The team’s results were published last week (January 11) in Conservation Biology.
To study the effects of road noise on frogs, Thierry Lengagne of the University of Lyon, France, and colleagues first recorded noise from a nearby high-traffic road. The scientists then played back the recording to 20 male frogs in the lab. After 10 days of 24/7 exposure to traffic noise at 76 decibels, the frogs showed signs of increased stress.
A single injection of inactivated poliovirus vaccine (IPV) could boost the immunity of children already vaccinated with multiple doses of live oral poliovirus vaccine (OPV), new research suggests.
A combination of the two vaccine types in routine immunisation programmes could help achieve global eradication of poliovirus, the researchers say. OPVs are cheaper and easier to administer but the intestinal immunity they provide against the virus weakens after a while. Children vaccinated with OPV can still spread the virus through faeces.
An international team of researchers has now tested the efficacy of IPV in boosting intestinal immunity of OPV-vaccinated children. In clinical trials conducted in the Moradabad district of Uttar Pradesh, they tested stool samples of nearly a thousand infants and children vaccinated multiple times with OPV. The children were divided into random groups and given either bivalent OPV (bOPV), containing type 1 and type 3 polioviruses, or IPV. A third group (the control) was not given any vaccine.