JOINT BASE SAN ANTONIO-FORT SAM HOUSTON, Texas —
Two researchers at Naval Medical Research Unit San Antonio at Joint Base San Antonio-Fort Sam Houston are studying the effectiveness of potential antivenom treatments in improving care for service members with snakebites.
Dr. Angela Jockheck-Clark, NAMRU-SA Combat Casualty Care Department research scientist, and Dr. Yoon Hwang, NAMRU-SA Maxillofacial Injury and Disease Department research scientist, are conducting research projects to find an antivenom that can be used by first responders to treat active-duty members and patients who are snake bitten, while reducing the effects of those snakebites on the body.
Both researchers started their projects three years ago after Navy Capt. Elizabeth Montcalm-Smith, the previous NAMRU-SA commanding officer, asked the unit’s researchers to see if they could develop an antivenom treatment that could be used to treat service members in the field.
Dr. Amber Mallory, NAMRU-SA Combat Casualty Care and Operational Medicine director, said Montcalm-Smith made her request to NAMRU-SA researchers after attending the Military Health Research Symposium in 2015.
“One of the gaps that was addressed at the symposium that the military faced is a need for a first responder treatment for snakebites,” Mallory said. “Capt. Montcalm-Smith came back to the command and posed a very open call to all the research scientists within the command to come up with unique ways to address this need.”
Responding to Montcalm-Smith’s request were Jockheck-Clark and Hwang.
“Dr. Hwang and Dr. Jockheck-Clark came up with unique ideas, both completely different approaches for neutralizing snake venom,” Mallory said.
Jockheck-Clark is focusing her research on developing a treatment that has the potential to delay access of toxic venom components to the blood stream and reduce the severity of tissue morbidities that are caused by some snake venoms. She is doing this by targeting a group of venom compounds known as spreading factors.
Spreading factors are found in every type of snake venom, and degrade the tissue around the envenomation site. This can result in edema, blistering, hemorrhage, tissue necrosis (killing of the cells in the tissue), and/or damage to nerve tissues. Ultimately, these spreading factors allow the venom to spread through the tissue and into the blood stream, where toxic venom components can cause life-threatening complications.
Current antivenom treatments are only effective once the venom has entered the bloodstream. She is hoping to find a treatment that can be used in the tissue around the snakebite before this happens. If successful, this approach would give the person bitten by the snake more time to get additional medical help.
“Right now, there isn’t anything you can really do to stop or slow the venom when it first gets injected,” Jockheck-Clark said. “That’s where my research project comes in. I want to be able to slow the venom at the site of injection. I’m doing this by targeting the spreading factors.”
Jockheck-Clark said further research will focus on developing a treatment that can treat and neutralize spreading factors found in various types of venom, which can contain between 26 to 100 different types of complex compounds.
She is hoping the results of her research will bring about a first responder snake bite treatment that will be available in an accessible form for both military and civilian medical personnel and can be applied anywhere, including austere environments and on the front lines, be stored at room temperature and is inexpensive to make.
At this point in her research, Jockheck-Clark said she does not have a timeline as to when a snakebite treatment could be available to military and civilian populations.
In his research, Hwang is experimenting with an antivenom that contains a bacteriophage, a virus that infects bacteria. The bacteriophage, or “phage,” is used to carry a small peptide (small fragments of proteins) which can target and stick to venom components, neutralizing the toxicity of the target snake venom proteins and components. The neutralized venom components are then safely cleared from the body.
Hwang said utilizing phage as a treatment for snake venom is safe because the virus only targets and infects bacteria, not human cells.
“Phage is known to be very stable, inexpensive to develop and easy to synthesize,” Hwang said.
Hwang said the experiments he has conducted so far in the laboratory show that four different kinds of phages with their peptides have the ability to reduce the activity of a major component in venom found in five different species of snakes in the U.S. and North America.
One of the venom components tested was from the Western Cottonmouth, which is one of the most common species of snakes found in military training and operational settings, as well as civilian areas, within the U.S.
Over the next two years, Hwang’s research will expand to study the effectiveness of phage-based treatments in treating other components in venom with the goal of developing a phage-based treatment that will be more portable and easier to use.
Snakebites pose a health risk to both military and civilian populations. Each year approximately 5.4 million people around the world are bitten by snakes, resulting in 81,000 to 138,000 deaths and over 400,000 being treated for long-term disability, wounds, amputations and ongoing psychological morbidity, according to a research report put out by Hwang and other NAMRU-SA researchers.
In addition, nearly 9,000 cases of snakebites are reported each year in the U.S. and Canada.