Overview
Toxoplasma gondii is a protozoan parasite that readily infects warm blooded mammals and is increasing in prevalence in cats, with approximately 16-40% of cats contracting T. gondii within the US. Additionally, Toxoplasma gondii can transmit to humans, sea otters, and other mammals due to contact with contaminated cat feces. However, there is no current vaccine or drug able to be set as a definitive standard treatment for T. gondii. In order to address these issues, RBHS iGEM has decided to pursue this project by utilizing bacteriophages to develop a vaccine that can be orally administered to cats.
Proposed End-Users & Vision of Usage
We want to reduce transmission of the parasite and infection, by focusing on cats, one of the most definitive hosts of T. gondii. Our proposed end-users are veterinarians, animal shelters, cat breeders, and cat owners. Veterinarians tend to treat cats and they will be able to provide our vaccine to their clients’ cats. Animal shelters and cat breeders tend to be places that are overcrowded and a breeding ground for infectious diseases and parasites. In these places, parasites like T. gondii can spread quickly, and cause much more harm because of lack of treatment available. By providing our vaccine to animal shelters and cat breeders, we can help reduce transmission of T. gondii significantly. By providing our vaccine to these end users, it can be ensured that more cats will be immune to T. gondii, resulting in less transmission to other warm-blooded mammals.
We plan on providing a vaccine, after going through more testing and experimentation to prove the capability of it. After confirming and creating the vaccine, we plan on releasing into the market as an orally administered vaccine. We chose to provide an orally administered vaccine, as it would cause the cats less stress when the vaccine is ingested rather than being administered with a needle through the skin.
Implementation
Introduction
Implementation of our vaccine, Toxoplasma gondii, will take multiple steps and stages before it can become licensed and marketable. In the United States, vaccine development is a long, arduous process that takes years of safety testing before the FDA can approve it to the market. We would also need to address safety and ethical concerns of our vaccine, before and during its implementation into the market, so that it can be properly distributed. As Toxoplasma gondii is a problem that occurs throughout the world, we plan to implement our vaccine globally; however, laws regarding vaccines will vary throughout the world.
More information about the laws and policies we would have to follow in the United States is done below under Laws.
Vaccine and Probiotics
We plan to implement an orally administered vaccine to cats. To do this, the materials used for the vaccine would have to change from the materials that we used in our wet-lab. Cats cannot digest certain compounds well, so our team has researched ahead to see which bacterial compound can best be used for creating a treatment for a cat. We consider using bacteria that are proven to be edible and safe, such as Lactococcus and Streptococcus thermophilus. We plan to use Lactococcus bacteria, in place of E. coli. Lactococcus bacteria are involved in the fermentation of dairy products and have not been found to be harmful to cats when consumed. Although we were unable to use this bacteria in our wet-lab, due to lack of time and resources, we would likely implement them in our proposed vaccine. We would consider using Caudovirales bacteriophages, which infect L. lactis, in place of the M13 phage in our system. Although Caudovirales bacteriophages are not filamentous phages, as are most commonly used for phage display, and are tailed phages instead, they are temperate. In fact, they would be able to display larger proteins and provide for peptide libraries that are more diverse, according to Jaroszewicz et al. in “Phage display and other peptide display technologies.”
We would also like to partner with cat food and medication companies that make cat probiotics. Putting our vaccine inside of probiotics would make it easier to administer cats this vaccine, as cats will more likely want to eat it. Many cat medications contain flavors and food that cats like to eat, and so they are being used more to administer to cats, instead of trying to inject the medication. Having food flavored probiotics with our vaccine will be easier to market and administer. In places like animal shelters and cat breeders, which typically are overcrowded, giving the vaccine in the form of food rather than injecting the vaccine saves time and energy of the shelter workers.
Reaching out to the Public
Our proposed implementation would also include our community’s perspective. RBHS iGEM released a survey during our season that asked questions regarding our proposed implementation, so that we could learn which approach is considered the best. We asked our community to rate from a scale of 1-5, the three approaches that we listed in our survey: restricting your cat from going outside, vaccination of cats, and food stations with medication.
Figure 1:
Our data from Figure 1, shows that 31.4% of our respondents rated restricting cats from going outside a 5, which was the highest bar in our graph. However, this isn’t a high percentage when you consider that about 70% of the rest of our respondents were not as confident with this approach. We acknowledge that cat owners would not want to restrict their cats from going outside, just to stop the spread of a parasite, because it would be considered inhumane and unethical to restrict the cats, as they are not aware of what they are doing wrong. This approach would not be successful, because we would have to use the law to enforce it, and even if that is done, people might feel that it is too restrictive and unfair to their cats.
Figure 2:
Based on the data from Figure 2, vaccinating cats was regarded as the best out of the three approaches we offered as a solution to the problem caused by T. Gondii. 65% of our respondents or 91 out of 140 people rated it a 5. In the modern age, many people are aware of the positive impacts of vaccination. This might have impacted more people’s decision to choose vaccination as an approach to our solution. At the point of releasing our survey, our team had already chosen to create a vaccine system. The results of our survey prove that our proposed implementation would be approved by the majority of our community, as a proper solution.
Figure 3:
The second most popular approach was putting out food stations with medication. 50.7% of our respondents believed strongly that this approach would be helpful. After doing research and consulting with experts, we decided that this might not be the best solution and proposed implementation to do, after we create a vaccine. The purpose of putting out food stations was to provide medication and vaccinate feral cats; however, we would need to ensure that these stations are properly maintained, so that the food we put out could get spoiled and infected. There is also a risk of other organisms eating the food, and being harmed due to the compounds of the food being indigestible and poisonous for these organisms. To set up these stations, we would need to ask our local government for help, but this might not be seen as a priority of the government.
Safety & Problems to Address
Potential safety concerns relating to the implementation of our project would be potential allergic reactions the cat could have from the edible vaccine. Some ingredients in the vaccine could cause an allergic reaction in certain cats. To prevent this from happening, it is critical that before cat owners give their cats this vaccine, they check with their vets to make sure that the ingredients are safe for the cat so that no allergic reaction will occur. Another concern is that even with lots of testing trials to ensure the vaccine’s safety, there is still a chance that the vaccine might result in potentially negative long-term effects which cannot be determined immediately. This risk always remains with any vaccine that is administered that there may be certain unknown side-effects that will not show up until much later. Testing the vaccine will involve some ethical concerns as initial testing with the vaccine on cats will involve high stakes and safety concerns for the animal.
Laws and Policies
In the United States, the law requires a lot of research, experimentation, and proof that a vaccine works before it can be licensed and put out into the market. This means years of research, studies, and experimentation must occur before a vaccine is established.
There are three main stages of vaccine development to follow to get a vaccine legally approved by the FDA. The first stage is laboratory and animal studies. When the desired immune response occurs in tissue-culture, cell-culture, or in mice, companies move on past this stage. Then, an application to the U.S. Food and Drug Administration called the Investigational New Drug (IND) must be filled out by the company. Once the IND gets approved, the next main stage that occurs is clinical studies with human subjects. However, for our proposed vaccine the studies would be done with cats. In this stage, 3 phases of vaccine trials must occur successfully, with each phase increasing the number of participants in the trial. The last stage that occurs is approval and licensure. After the trials have occurred, a Biologics License Application is filled out and sent to the FDA. Once it has been approved, a license for the vaccine is given, but monitoring of the vaccine would still likely occur. As a high school team, this would have not been possible for us to do in the time frame we were given in the season. Also, we would not be able to go through the long process needed by the FDA, due to a lack of resources.
There are policies regarding vaccinations for humans, but not necessarily for pets. It is recommended that cats are given core vaccinations by their veterinarians. However, this is not always easy or possible in places like animal shelters and cat breeding areas, as it is overcrowded and there is a lack of treatment. Our proposed implementation of a vaccine probiotic provides cats that would not usually be provided such treatments, a treatment that can help protect them and reduce transmission of the parasite.