Scientists find study method for Crimean-Congo hemorrhagic fever virus

black-legged tick

black-legged tick

Scientists from the University of Texas Medical Branch at Galveston recently discovered a way to observe ticks that carry the Crimean-Congo hemorrhagic fever virus, a biosafety level four contamination, without putting themselves in danger.

When first brainstorming, the scientists thought they could wear a “spacesuit lab” to protect themselves from the risk of contracting the virus.

“It was completely new territory for us,” Dennis Bente, UTMB assistant professor and senior author of the paper, said. “Ticks are very small, and in the BSL4 you have two pairs of gloves on, you have this bulky suit, you have the plastic visor — all these things are a huge handicap. So how do you make sure you contain them?”

The team placed “feeding capsules” onto mice, then placed the ticks of a species known to carry the virus onto the mice one by one. Most ticks attach themselves to a host and slowly feed off of it for a few days.

Once the ticks attached themselves, each tick was accounted for and then the mice were placed in a sealed glove box lined with sticky tape to prevent the escape of a tick. The mice were, at this point, injected with the virus.

“We did hours upon hours of testing to get this system working,” Bente said. “We tested different types of sticky tape to determine the one that best inhibited the ticks’ mobility, we tried different gloves, we tested the work flow, we checked to see how long a tick could last if you submerge it in disinfectant.”

The experiment was a success. Researchers now have a way to study how the virus is contracted and spread during this window of a few days, without putting researchers at risk of contracting a deadly virus.

“Ticks play such a vital role in the epidemiology of the disease — they’re not only the vector but they are also the reservoir for the virus, yet nobody really knows what’s happening to the virus in the ticks, because there’s been no way to study it in the laboratory,” Bente said. “Now we can look at the complete transmission cycle in a controlled setting, examining how the virus is passed from infected animal to the uninfected tick, and from the infected tick to the uninfected animal. That’s something that people studying this in the field haven’t been able to do before now.”

The study was published in Frontiers in Cellular and Infection Microbiology.

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