By Michael Howell
The Zika virus has suddenly gotten the world’s attention and, subsequently, it’s gotten the attention of a group of scientists working at Rocky Mountain Laboratory (RML) in Hamilton.
“We’ve worked on a group of viruses that Zika virus is related to, called flaviviruses, for over ten years here at Rocky Mountain Laboratories,” said Dr. Sonja Best. “In particular we’ve been interested in how those viruses interact with the host’s immune response and what aspects of those are critical for the virus to be able to either take hold and cause disease, or, for the host to be able to clear infections. We study the mechanisms of virus virulence or host protection.”
Dr. Best, who heads the Innate Immunity and Pathogenesis Unit at RML, said that the plan now was to integrate study of the Zika virus with their ongoing work program.
“We will look at how the virus causes disease and what aspects of our immune response can help us recover from infection,” said Best. She said those studies hopefully can be expanded to develop a mouse model for infection so that they may better evaluate how the virus works and, if therapeutic targets arise such as drugs or antibodies that can be tested, or a vaccine, then they will have an animal model in place and be able to check them. That’s the plan for the next ten or twelve months.
Dr. Best said her group will be working on that as part of their existing program. They have been studying West Nile and dengue viruses, both “cousins” of Zika. Information learned about West Nile and dengue can be applied to Zika because, while different, they are in the same family of viruses (called flaviviruses).
But they are also pulling together three or four different investigators in RML that have different expertise in vaccine development, assessment of the role of antibodies in protection, and the interface between the virus and the immune response to help tackle some of these questions.
According to Dr. Best, Zika is not a deadly disease, like Ebola, for instance. The vast majority of people who get the Zika virus don’t show any symptoms. For the adults who do show symptoms it is usually a fever, a rash, some joint pain, or red eyes, and that is resolved within a few days.
The real danger presenting itself in the latest Zika outbreak in Brazil is the growing evidence that it is connected to a growing incidence of microcephaly in Brazil. Microcephaly is a general term that covers a type of birth defect in which the infant is born with an underdeveloped brain and small head. Other diseases have been related to the same sort of defects. Rubella can cause microcephaly as well, for instance.
The growing body of evidence relating the Zika virus to microcephaly and the potential for sexual transmission that has been documented in two cases make it a concern for men who are returning from a place where the disease is endemic and having sex with a pregnant woman.
This type of transmission is about the only concern here in Montana, according to Dr. Best, because the virus is predominantly transmitted by mosquitos and the mosquito species that transmits the virus has a limited distribution within the United States. The effects here will be limited because the mosquito vector is limited here.
“There is no mosquito vector here in Montana,” she said, “We may have travelers come in from infected areas, but it is highly unlikely that we will ever see it in the mosquito population here in the northwest.”
The mosquito species does exist in the southern U.S. in places like Florida and Texas, and they do have a lot more exposure to travelers from regions where it is endemic. Dr. Best said Florida had just declared it a health emergency and is issuing advisories, but nothing has happened yet.
“Because we don’t have a vaccine or a treatment for this disease the most effective way of control is to control the mosquito vector,” said Dr. Best. “Stop backyard breeding and limit opportunities for biting as well by using repellant and proper clothing.”
Work on the disease at RML is scheduled to begin next month.