Many children develop tinnitus, or ringing in the ears, but a virus that can kill cells in the ear canal and trigger the condition has also been detected in Chinese rats, researchers say.
The common cold, often with flu-like symptoms, is well-known for causing people to run a fever. But back in the day, diseases like mumps, salmonella, and measles were also called by those nasty diseases. Now, people have become much more careful with their immune systems, so it’s easier to distinguish cause and effect when human viruses and other microbes are mixed.
More recent reports claim that the cold virus, known as shingles, may actually cause nerve damage, as well. In some cases, when the virus breaks out of the white blood cells in the head and starts to inflame nerve tissue on the brain and spinal cord, nerve pain can be a side effect.
But a new study, published recently in the journal Human Molecular Genetics, suggests that a virus called CVID, or “Co-infection Virus with c-Ethylphthalate, leads to the death of cells and the development of tinnitus in Chinese rats, even if they have received antiviral treatment, researchers say.
Since most diseases, like malaria and HIV, enter the body by making contact with a host, the study shows that CVID can also infect the inner ear cells, researchers say.
“Viral infection is not just a threat to the nose and mouth but the whole body,” said researcher Xu Quan, an associate professor at the University of Sydney. “Viruses are potentially deadly, and our findings show that CVID, one of the most common viruses which causes headache, is not just harmful to humans but can affect the brain and the ear.”
The researchers first noticed that the treatment of CVID actually causes a condition called tinnitus, pronounced “trum-then.” When the mice were given CVID or control drugs, the cells that would normally send pain signals in the ears failed to act, the researchers say. And these cells were gone up to 20 days after infection, the study showed. But if the cages were placed in another lab, the c-Ethylphthalate in the rats’ ears returned to normal.
But researchers said that the study shows that nerve endings in the ear have a major effect on the health of these cells.
“Not only are there problems with the nerve cells, we found that the T cells are not responding, which implies that they are infected with the virus themselves,” said PhD candidate Park Jung-hwan, who worked on the study.
The CVID virus is a herpes virus, a type of virus that causes cold sores, said study author Dr. Manvi Prasad, director of the Infectious Diseases Section of the Department of Pathology at the University of Melbourne.
“It has been suspected that a number of diseases could be caused by these infections, including immune deficiencies and infectious diseases,” Prasad said.
As more rats are used in larger studies, the likelihood of finding CVID to be a candidate for a specific infection increases, the researchers say.
But a lack of protection in the animal brains, which produces pain signals that the brain looks for, could make CVID a bad choice for transmitting the disease, Dr. Pavan Kumar, a pediatric infectious disease specialist at New York University Langone Medical Center, told Live Science.
“Humans and mice are very different in their molecular and physiological systems,” Kumar said. “One thing that should be kept in mind is that a significant number of human neurons, who make these signals, are located in the ear canal.”