MONDAY, Sept. 25 (HealthDay News) -- Researchers have uncovered how herpes infects the cornea, which may help explain how it escapes the immune system.

Both strains of the herpes virus -- HSV-1, the type that causes cold sores in the mouth, and HSV-2, which causes genital herpes -- can infect the cornea of the eye. Ocular herpes is the leading cause of infectious blindness in the United States. An estimated 400,000 Americans have some form of the disease, according to the National Eye Institute.

Reporting in the Sept. 25 issue of the Journal of Cell Biology, researchers from the University of Illinois at Chicago College of Medicine found that HSV-1 enters the first layer of the cornea to infect the inner layer, the stroma, in a process similar to the way that bacteria and viruses are engulfed by immune cells called phagocytes.

"In the electron microscope pictures, it looks like the stroma cells form long arms that reach out and collect the virus particles, and then wrap around them, forming a sac, and bring them into the cell body," study senior author Deepak Shukla, an assistant professor of ophthalmology, visual science, microbiology and immunology, said in a prepared statement.

But unlike phagocytes, which destroy foreign particles, the herpes virus emerges from the stroma undamaged and able to infect the cell.

"This raises the interesting possibility that herpes may be able to evade the immune system defenses in the same way," Shukla said.

"Understanding herpes' unusual pathway for infecting the stroma cells opens up new strategies for developing therapies against this potentially blinding disease and has implications for understanding other herpes virus infections," he said.

More information

The American Academy of Family Physicians has more about herpes.