4- One Health.docx

- **Zoonosis: General Info** - 60% of existing human diseases are zoonotic - At least 75% of emerging infectious diseases oh humans (Ebola, HIV, influenza) have an animal origin - 80% of agents with potential bioterrorist use are zoonotic pathogens - 5 n...

- **Zoonosis: General Info** - 60% of existing human diseases are zoonotic - At least 75% of emerging infectious diseases oh humans (Ebola, HIV, influenza) have an animal origin - 80% of agents with potential bioterrorist use are zoonotic pathogens - 5 new human diseases appear every year, with 3 of them being of animal origin. - Tracing the origin of zoonotic viruses requires a one health approach - **One health** is not only about zoonoses, but also animals whoa re at threat from human viruses too. - A lioness dies of covid-19, and 9 other tested positive for it. - Human metapneumovirus infection kills chimpanzees. - **SARS-CoV (2002-2003)** - Step 1: Recombination and mutation events of the virus took place within bats. - Step 2: Rapid mutations and successful spread among vices took place in wet markets, - This was facilitated by stress, crowding, and immunosuppression. - Step 3: In humans, several independent spillovers took place, with some strains of the virus undergoing further mutations, which led to an epidemic. - **MERS-CoV** - MERSr-COV in bats use the same host receptor as MERS-CoV. - This was possibly acquired by recent recombination events of the virus. - This virus originated in bats and spilled over into camels at least 30yrs ago. - The virus is now (since 2012) prevalent in camels, and they have spread the virus to humans. - **SARS-CoV-2 (Covid-19)** - Bat CoV RaTG13 - This has \~96% sequence homology with key differences in its genetic features. - This spread to pangolins and other intermediate hosts, before it spread to humans. - The spread of this virus to these intermediate hosts took place in wet markets, and it is closely related to RBD. - **Bat CoV RmYN02** - S1/S2 cleavage site insertion - 97% homology replicate gene - 82% overall homology - **SARS-CoV-2 in humans** acted similarly to FIP in cats. - Both causes an increased release of cytokines (AKA: Cytokine shower). - However, in humans, the cytokine shower, alone, is what killed people. - For those who survived the cytokine shower, this shower triggered a hyper immune response, causing the release of inflammatory fluid, killing people by essentially drowning from the fluid buildup in their lungs. - Dexamethasone (steroid) was one of the main prophylactic treatments to help prevent the fluid build up in humans. - **Coronavirus: General Info** - Lessons from animal viruses aid in tackling emerging human viruses and vice versa. - For example, over 3 decades of research on several animal coronaviruses, including therapeutics and prophylaxis is what allowed people to learn how to tackle the human coronavirus which received increased attention after the 2002-2004 SARS outbreak. - CoV= coronavirus - **Coronaviruses are enigmatic due to their behavior.** - **Pantropic Canine Coronavirus (in dogs)** - This virus started as causing self-limiting diarrhea in puppies, and generally mild infection. - After 2006, the virus progressed to being a highly virulent pantropic CoV with acute systemic disease. - This new version of the virus has tropism for internal organs and has a high case fatality. - However, the genetic changes inducing high virulence and switch in pathogenicity have not been proven. - **TGEV to PRCoV (in swine)** - TGEV (Transmissible Gastroenteritis Virus) is an enteric virus that causes severe diarrhea and has a high mortality rate in piglets. - TGEV had a part of its RNA removed (depletion of \~600nt at the 5' end of the S gene), which caused the virus to transform into PRCoV. - PRCoV (Porcine Respiratory Coronavirus) causes mild upper respiratory disease in pigs and induces an immunity against TGEV. - **Feline Coronavirus (in cats)** - The feline coronavirus causes FIP in 1-3% of cats with the virus. - 70% of these cats will have a transient infection with mild diarrhea. - 5-10% of these cats will have a resistant infection. - FIP involves the cat's monocytes becoming infected, which then triggers the release of cytokines (known as a "cytokine shower"). - The cytokine shower causes systemic inflammation. - **Animal coronavirus vaccine issues** - Lack of complete protection - Short duration of immunity - Virus shedding from vaccinated animals - Correlates of protection against CoVs - Emergence of multiple serotypes/subtypes including virulent recombinants between vaccine and field strains - ADE (antibody dependent enhancement) enhanced disease - **Learning from coronaviruses in animals** - Animal coronaviruses allow humans to learn from: - Host-pathogen interactions in bats and other intermediate hosts, especially host immunity - Molecular epidemiology, pathogenesis, and therapeutic and prophylactic strategies in animals - Enigmatic coronaviruses of animals have changes in viral genome that alters tissue tropism and pathogenicity. - Animal coronavirus vaccines have showed humans various strategies, whether or not they are effective, and possible side effects (ADE). - The use of animal models teaches humans about pathogenesis, immune responses, therapeutics, diagnostics, and vaccines. - **One Health** - Pathogens and toxins are transmitted to the environment, animals, and humans through channels, like water, soil, and animal handling. - **Food safety** requires teamwork to identify these channels. - The one health approach of "food safety" makes our food safer. - Risks of improper food safety can lead to Norovirus and Rotavirus in humans. - Food security is a threat of transboundary viral diseases, such as Rinderpest (in South Africa). - In the 1890s, the Rinderpest virus killed more than 5.2million cattle south of the Zambezi river in Africa. - This led to starvation which resulted in the death of an estimated third of the human population of Ethiopia and 2/3 of the Maasai people of Tanzania. - This is an example of One health playing a role of economists. - One health plays aids **mental health** by educating people about illnesses to prevent their ignorance and stereotyping, that would otherwise lead to there being stigmas against certain groups of people (decreasing their mental health). - The **one health triad** includes: healthy people, healthy environment, and healthy animals.