AUG 06, 2018 7:58 AM PDT

How Undetected Viral Infections Impact our Health

WRITTEN BY: Carmen Leitch

It seems that when people are infected with a virus but don’t have any obvious symptoms, there may still be effects. Reporting in the Journal of Virology, scientists at UC Davis have found that even at low levels, CMV or cytomegalovirus exerts a significant impact on the microbes and immune cells in our bodies. It also changes how our body responds to a variety of things, including the flu vaccine.

Cytomegalovirus (CMV) infection of a lung pneumocyte / Credit: CDC

"Subclinical CMV infection alters the immune system and the gut microbiota in the host, and that impacts how we respond to vaccines, environmental stimuli, and pathogens," said senior paper author Satya Dandekar, chair of the Department of Medical Microbiology and Immunology at UC Davis. She is also a core scientist in the infectious diseases unit at the California National Primate Research Center at UC Davis. "This study highlights the role of these silent, latent viral infections that are totally asymptomatic," she added.

Though you may have never heard of it, CMV is a common virus. It infects as many as 70 percent of adults that live in the United States and Europe and up to 90 percent of those in Africa. CMV is not considered to be a threat to human health, however. In people with immune systems that are not functioning well, like the elderly or those with HIV, it could have a more significant impact.

 While most of those CMV infections don’t get diagnosed, they still have an influence. The team at the Dandekar lab wanted to know more about these potential effects. They turned to an animal model for their work.

In CMV-infected animals, bacteria that produce butyrates, like Firmicutes, were present at higher levels. While butyrates may reduce inflammation, they might also increase the expression of genes that encourage CMV to live on in the body. 

The immune system of the infected animals also appeared to be hard at work; there were higher levels of some immune cells like lymphocytes and inflammatory T cells. While immune activity seemed to be increased by CMV, there was a diminished response to a flu vaccine.

"There's a high degree of variation at the population level of how people respond to vaccines," said Dandekar, "and all the factors that contribute to these variations are not fully understood. Our paper shows the subclinical CMV infections may be one of the issues that contributes to that immune variation. This opens a new opportunity to come up with novel approaches to optimize and position the immune system to have higher quality responses to vaccines."

More research will be necessary to fully understand the effects of low-level CMV infections. The immune system might get worn out from a constant battle against these infections, for one thing. The Dandekar lab will be continuing their studies.

"This highlights the impact silent viruses have to influence how the host responds to vaccines," said Dandekar. "Can we somehow use this information to optimize our immune system? That's the direction we would like to go to see how we can inhibit CMV to see if we can enhance the vaccine response."

Learn more about CMV from the video.

Sources: AAAS/Eurekalert! Via University of California Davis, Journal of Virology

About the Author
  • Experienced research scientist and technical expert with authorships on over 30 peer-reviewed publications, traveler to over 70 countries, published photographer and internationally-exhibited painter, volunteer trained in disaster-response, CPR and DV counseling.
You May Also Like
MAR 30, 2021
Microbiology
A Marburg Virus Treatment Approach is Identified
MAR 30, 2021
A Marburg Virus Treatment Approach is Identified
Marburg virus causes severe hemorrhagic fever; its fatality ratio can be as high as 88 percent. Researchers may have now ...
APR 05, 2021
Microbiology
Salmonella Outbreaks Linked to Bird Feeders, Pet Turtles
APR 05, 2021
Salmonella Outbreaks Linked to Bird Feeders, Pet Turtles
Many types of bacteria often live harmlessly in and on animals and humans, but some bacteria pose a threat. Salmonella b ...
APR 23, 2021
Microbiology
A Causal Connection Between C-Section Births & Food Allergies
APR 23, 2021
A Causal Connection Between C-Section Births & Food Allergies
The microbes that live in the human gut have a powerful influence on our health, and that microbial community is with us ...
APR 29, 2021
Immunology
A Week for World Immunization
APR 29, 2021
A Week for World Immunization
The World Health Organization (WHO) is calling our attention to World Immunization Week, which comes in the last week of ...
MAY 02, 2021
Microbiology
Fasting Alters Gut Microbiota, Lowering Blood Pressure
MAY 02, 2021
Fasting Alters Gut Microbiota, Lowering Blood Pressure
Increasingly, microbes in the gut are being linked to human health and disease. New research has suggested that disrupti ...
JUN 03, 2021
Microbiology
How HIV Can Deplete White Matter in the Brain
JUN 03, 2021
How HIV Can Deplete White Matter in the Brain
The brain is sometimes called grey matter, which is made up of neurons. But it also contains white matter, which are neu ...
Loading Comments...