A batty solution? The potential vaccine for future outbreaks
Bats may well be the answer, so why not try?
As the global pandemic of Covid-19 spreads, and the death toll climbs, identifying the origins and history of the disease is prudent. Working toward a possible vaccine is essential. Regardless of how and when the virus may flatten or resurge, a new plan is urgently needed to prevent such pandemics in the future.
Researchers can develop a vaccine now to offer protective immunity. Recently a protective vaccine tested in six monkeys holds some promise. However, even if researchers develop a promising vaccine today, it would have to be tested for effectiveness and safety and may not be available to the public for 18 months. Realistically the vaccine may not be available for at least 15 years. Still, instead of making a vaccine for people for every epidemic, it may be easier to predict where the virus originated and then apply the vaccine at the source of infection to prevent the outbreak in the first place.
The answer could be with bats, though the White House recently cancelled funding to the National Institutes of Health for research on a bat sampling project in China through the EcoHealth Alliance.
As a researcher in the Department of Microbial Pathogens and Immunity at Rush University Medical Center, I study viruses and the role of the host immune system in controlling the pathogen. So I understand how critical vaccines are in protecting people form initial infection. Vaccines can attack the virus at its source and prevent it from getting to people in the first place.
A recent study of the coronavirus present in the lungs of six symptomatic patients from the Wuhan wet market (epicentere of Covid-19) had a genetic finger print that was 96 percent identical to coronavirus found in bats. Researchers need further evidence to establish the relationship between bats and the coronavirus infection in humans. Coronaviruses are not the only viruses originating from bats.
Viruses linked to human diseases that many believe originate from bats include Rabies, Marburg, Ebola, Nipiha, and Hendra viruses.
Although vampire bats are responsible for spreading rabies, the bats that spread the other zoonotic viruses are considered to be from insectivorous or fruit bats. The way they transmit the viruses to other animals and humans is likely through feces or saliva that are spread to humans or other animals through inhalation or exposure to mucosal surfaces.
The information that bats may be the source of deadly viral outbreaks does not mean that we should eliminate bats. Bats are critical for our ecosystem, including but not limited to, eating harmful insects and pollinating plants that bear fruit we consume.
The reason more infections are originating from bats is not due to the consumption of bats or the animals they infect, but through deforestation, since trees are home to many species of bats. To prevent future pandemics, slowing deforestation will help, but also, develop vaccines for viruses that afflict bats will also be helpful.
To begin the vaccine process, with next-generation sequencing, researchers can randomly collect a sample of bat saliva and feces to extract genetic material from these samples, and the virus genome is then sequenced.
From this genetic information, researchers can generate vaccines to administer to the bats. Researchers will not immunise bats by injecting every bat individually with a vaccine. Instead, they can administer the vaccine on the fur of a few of the flying mammals. Bats are social creatures and habitually live in colonies where they engage in a ritual of grooming each other. During this process, the vaccine gets into mucosal surfaces. It develops a protective immune response to neutralise the virus and thus preventing the spread of viral infection among the colony.
Many of the bats will likely get vaccinated, but those who are not, will be protected through a process known as herd immunity. Since the majority are immune, it is improbable that some bats who are not immune will come into contact with a bat that is infected.
Ever since 1966, when healthcare workers initially identified the family of coronavirus in patients presenting with symptoms of cold, there have been three strains of this virus that led to widespread infections in the human population.
The first virus (SARS virus) struck in 2002 in southern China and quickly lead to pandemic involving 29 countries in North America, South America, Europe, and Asia. Of the 8,098 reported infections, 9.4 percent were fatal.
The second coronavirus outbreak in 2012 hit 27 countries in the eastern Mediterranean region, leading to the Middle East respiratory syndrome (MERS). The MERS virus led to 2494 reported infections with a fatality rate of 34.4 percent. The last strain of the SARS virus (SARS2) that started in late 2019 has led to deaths in nearly 7 percent of the individuals infected. To curtail further spread of the virus and to prevent future outbreaks from novel viruses, scientists must understand where the virus originated.
In the three major coronavirus outbreaks, experts report animals were likely transmitting the virus to humans. For example, the initial SARS outbreak in 2002 may have occurred in a southern China market where living animals for food are displayed.
Although the source of the first SARS outbreak appeared to come from Civets at a market in southern China, many other animals such as domestic cats had the virus as well. In the MERs outbreak, it was believed that camels were the source. In the case of the latest SARS outbreak, it was thought to be pangolins. These animals however may serve as a conduit for the virus from a precursor host, bats.
In the first SARS pandemic, the Horseshoe Bat was believed to be responsible for initial transmission to humans. Many of these concepts and approaches are not new. But in the wake of a global spread of this virus, implementing these simple approaches can likely save many lives in probable future outbreaks.