Australian scientists closer to Hendra virus vaccine thanks to an alpaca named Pedro | 7.30

Key Concepts:

• Hendra Virus (HeV): A deadly virus carried by flying foxes, transmissible to horses and humans.
• Nipah Virus (NiV): A related virus with potential for human-to-human transmission.
• Flying Foxes (Bats): Natural reservoir for Hendra virus.
• Vaccination (Horses): Prevention method for Hendra virus in horses.
• Nanobodies: Single-chain antibodies derived from alpacas, used as potential therapeutic agents.
• Agonal Struggles: Violent, involuntary muscle contractions during the process of dying.
• Antigen: A substance that induces an immune response in the body, especially the production of antibodies.
• In Vitro: Studies conducted outside a living organism, typically in a laboratory setting.
• In Vivo: Studies conducted within a living organism.

The 1994 Hendra Virus Outbreak in Brisbane:

• Initial Incident: In September 1994, 11 thoroughbred horses died at Vic Rail's stables in Hendra, Queensland. The incident made national headlines and disrupted the horse racing industry.
• Veterinarian Response: Peter Reed, a veterinarian, was the first to respond. He described the scene as gruesome, with horses dying in "agonal struggles."
• Symptoms: The horses died due to respiratory failure, as their lungs filled with fluids. The virus attacks all organs in the body, but primarily targets the lungs and brain.
• Total Impact: 13 horses died, and 7 recovered with antibodies. Vic Rail, the owner of the stables, also contracted the virus and died.

Identification and Origin of the Virus:

• New Virus: The virus was identified as a new virus, never seen before.
• Naming: Two years later, the virus was named Hendra, after the suburb where the outbreak occurred.
• Source: Scientists confirmed that the virus is carried by flying foxes. Horses contract the virus through contaminated pastures, feed, or water via bat excrement.
• Prevalence: It's estimated that 70-80% of bats have carried the virus in their lifetime. Hendra circulates in bat populations across Australia, Asia, and Africa.
• Ongoing Threat: Since its discovery, there have been 68 outbreaks and 110 horse deaths.

Human Impact and Mortality:

• Human Cases: There have been four human fatalities from Hendra virus.
• High Mortality Rate: The mortality rate in humans is close to 60%.
• No Human Vaccine: There is currently no vaccine for humans for Hendra virus.

Research and Therapeutic Development:

• Dr. Ariel Isaac's Work: Dr. Ariel Isaac is working on developing therapeutics and vaccines for Hendra virus and related viruses.
• Nipah Virus Connection: Hendra virus is related to Nipah virus, which has the potential for human-to-human transmission and explosive outbreaks.
• Nanobody Discovery: At the University of Queensland, Dr. Isaac's team discovered a nanobody that can neutralize the virus.
• Pedro the Alpaca: They collaborated with a farm in Chile, where an alpaca named Pedro was immunized with a Hendra/Nipah virus antigen. Pedro produced unique antibodies called nanobodies.
• Nanobody Mechanism: The nanobody DS90 works by locking the viral protein in its native confirmation, preventing it from entering cells.

Future Directions and Preparedness:

• Human-Ready Therapy: The next step is to develop a human-ready therapy based on the nanobody.
• Stockpiling: The goal is to have stockpiles of vaccines and therapeutics available to protect vets, handlers, owners, and the general population in case of an outbreak.
• Preventing Pandemics: A vaccine or therapy would help contain the virus and prevent widespread infections and potential pandemics.

Hendra Today:

• Suburb Transformation: The Hendra suburb has transformed, with luxury homes replacing the stables.
• Peter Reed's Reflection: Peter Reed finds it traumatic to revisit the events but hopes that reminding people about the horror of the outbreak will encourage preventative measures.

Synthesis/Conclusion:

The Hendra virus outbreak in 1994 was a significant event with devastating consequences for horses and humans. While a vaccine exists for horses, there is no human vaccine or specific therapy. Ongoing research focusing on nanobodies derived from alpacas offers promising potential for developing effective treatments and preventing future outbreaks and potential pandemics. Preparedness through stockpiling vaccines and therapeutics is crucial for mitigating the impact of future Hendra virus outbreaks.