VM2001_EID_2025

Zoonosis is a pathogen that is shared by both humans and non-human animals and can be transmitted from one to the other. The term comes from the Greek words 'Zóon' meaning animal and 'Nóso' meaning disease.

60% of existing human infectious diseases are zoonotic.

At least 75% of emerging infectious diseases in humans have an animal origin, including diseases like Ebola, HIV, and influenza.

Over 800 out of 1,400 pathogens identified in humans are shared with animals.

The parasite Trichostrongylus tenuis contributes to regulating the Red grouse population by preventing over-use of resources, such as food. This regulation is evident in the oscillating patterns of Red grouse abundance, where the presence of the parasite influences population dynamics over time.

The environment refers to the surroundings or conditions in which an organism lives or operates.

Food-borne transmission occurs when a host is infected through contact with food contaminated with pathogenic microorganisms.

Air-borne transmission occurs when microorganisms that are too small can move through the air from one host to another.

Fomites are any inanimate objects or surfaces where pathogens can survive until infecting a susceptible host.

Water-borne transmission occurs when a host is infected through contact with water contaminated with pathogenic microorganisms.

Vector-borne transmission occurs when some pathogens require an animal species to complete their life cycle before infecting a susceptible host.

Humans have a negative impact on elephant populations, which can affect the overall balance of the ecosystem.

Mutualism is a symbiotic relationship between two or more species where both parties benefit, represented as (+/+).

Commensalism is a symbiotic relationship where one party benefits while the other is not affected, represented as (+/0).

Competition is when organisms compete for limited resources such as food, territory, and mates. It can occur between members of the same species (intraspecific) or between different species (interspecific).

Competition is a (-/-) interaction because both parties involved are negatively affected.

An example of interspecific competition is when members of two different species, such as a lion and hyenas, compete for the same resource, like food.

Predators are always in a higher trophic level than their prey. Predators can be at least secondary consumers or above, while prey can be primary consumers (herbivores).

Predation is a (+/-) relationship where the predator benefits by killing and eating the prey, which can lead to fluctuations in the populations of both predator and prey species.

Predators are always in a higher trophic level than their prey. Predators can be at least secondary consumers, while prey can be primary consumers (herbivores).

An obligate pathogen is a microorganism that must infect a host to survive and multiply.

A facultative pathogen can infect and multiply in a host but is also capable of multiplying in the environment, unlike an obligate pathogen which requires a host for survival.

An opportunistic pathogen is a microorganism that does not ordinarily cause disease but may become pathogenic under certain conditions, such as impaired immunity.

Pathogens are microorganisms that can cause disease upon colonization of the host.

Infection is the invasion and multiplication of pathogens in an individual or population.

A host is an individual (or cell) that is susceptible to being infected by a pathogen.

Infectious diseases are diseases caused by pathogens such as bacteria, viruses, prions, parasites, or fungi.

Communicable diseases are diseases that can be spread directly or indirectly from one animal to another (contagious).

Early beliefs attributed diseases to an imbalance of humours, spirits, bad omens, or a curse.

The two main categories of causes for diseases are genetic/metabolic disorders and infectious diseases.

An emerging infectious disease is defined as a disease that is newly recognized or newly evolved, or that has occurred previously but shows an increase in incidence or expansion in geographical, host, or vector range.

A re-emerging infectious disease is one that appears after it has been eradicated or has experienced a significant decline in incidence.

Various birds, especially robins in the U.S.

Wildlife markets and trade; global travel.

The first human case occurred in Hong Kong in 1997.

It currently picks up ~7000 public health threat signals every month.

Large-scale livestock production; presence of orchards on pig farms; date palm sap harvest.

Humans, horses, and dogs.

The first human case was in Veracruz, Mexico in 2009.

Taxonomic groups with more host species generally hold more potentially zoonotic pathogens.

The tropics hold the largest number of zoonotic pathogens, despite their worldwide distribution.

The order Chiroptera has 25 species.

Carnivora has 83 species, while Primates have 61 species, indicating that Carnivora has more species than Primates.

Species richness is crucial for ecosystem health as it contributes to biodiversity, resilience, and the ability of ecosystems to provide services and adapt to changes.

The probability of finding a zoonotic virus increases with the number of virus types held by the species host. Species such as rodents, bats, and primates have a larger number of recorded viruses, suggesting they may harbor more viruses with zoonotic potential compared to species like rabbits or birds.

The decline in bat populations can lead to an increase in mosquito populations, which may result in higher rates of mosquito-borne diseases. Additionally, bats play a crucial role in pollination and seed dispersal, affecting the growth of certain plants like durian trees, which in turn impacts local ecosystems and food sources such as tequila production.

Biodiversity loss can lead to increased disease emergence as it disrupts ecosystems and reduces the natural checks on pathogen populations.

Climate change alters habitats and can expand the range of vectors, leading to increased transmission of diseases.

Land use change can create new habitats for pathogens and vectors, facilitating the spread of diseases to new areas.

The relationship is characterized by two effects:

1. Dilution Effect: Lower biodiversity leads to a higher risk of infection. When fewer species are present, the most common host species dominates, increasing the likelihood of disease transmission.

2. Amplification Effect: Higher biodiversity can increase the risk of infection because some pathogens can infect multiple host species. For example, including dogs in the ecosystem may amplify transmission rates.

The effects of climate change on the spread of Dengue virus include:

1. Increased vector abundance and feeding activity: Warmer temperatures can lead to more mosquitoes, which are the primary vectors for the virus.

2. Increased geographical range: As temperatures rise, the habitats suitable for mosquitoes expand, allowing them to thrive in new areas.

3. Increased human activities during warmer times: Higher temperatures can lead to more outdoor activities, increasing human exposure to mosquito bites.

Land use change, particularly the expansion of palm oil plantations, alters the habitat and behavior of both the mosquito vectors and the macaque hosts, facilitating the transmission of Plasmodium knowlesi from macaques to humans. This change in land use increases human exposure to infected mosquitoes, thereby elevating the risk of malaria transmission.

The adaptation of Plasmodium knowlesi to humans poses a significant public health risk as it can lead to increased malaria cases in human populations, particularly in areas where land use changes have occurred. This adaptation highlights the need for effective surveillance and control measures to prevent outbreaks and protect vulnerable communities.

Environmental factors influencing the transmission cycle of Plasmodium knowlesi include the proximity of human settlements to forests, agricultural land, and areas cleared for plantations. These factors affect mosquito biting rates and the likelihood of infected bites, thereby impacting the overall risk of malaria transmission.

Land use change in oil palm plantations increases the abundance of generalist animal species, which in turn raises the prevalence of multi-host parasites like echinostomatids. This creates a higher risk of infection for humans, particularly for those working in or around these agricultural landscapes, such as fishermen, crop workers, and farmers.

Generalist animal species adapt to various environments, including man-made ecosystems. Their increased abundance in agricultural landscapes leads to a higher prevalence of multi-host parasites, which can increase the risk of human infections.

The lifecycle of echinostomatids involves multiple hosts, including fish and snails, which are prevalent in oil palm plantations. This complex interaction, facilitated by land use change, poses a significant public health risk as it can lead to increased human infections among those who interact with these environments.

Zoonotic spillover refers to the transmission of pathogens from a reservoir species (such as animals) to a novel species (such as humans) that can result in disease. This process can be stochastic, meaning it can occur randomly, and involves both zoonotic and non-zoonotic pathways.

Grass has a positive impact on rainfall, suggesting that healthy grasslands can contribute to better rainfall patterns.

Canine distemper can lead to reduction of populations and local extinctions among affected species. For instance, approximately 30% of the Serengeti lion population has been impacted by this virus, which can disrupt the ecosystem balance.

The conservation status of the Flat-headed cat (Prionailurus planiceps) is Endangered.

The Marbled cat (Pardofelis marmorata) has a conservation status of Near threatened.

The Leopard cat (Prionailurus bengalensis) has a conservation status of Least Concern, while the Bornean bay cat (Catopuma badia) is classified as Endangered.

The conservation status of the Sunda clouded leopard (Neofelis diardi) is Vulnerable.

Serological evidence indicates exposure to feline-related viruses at the domestic animal-wildlife interface, highlighting potential pathogen transmission between domestic and wild species.

The study focused on several feline-related viruses, including Feline Coronavirus (FCoV), Feline Panleukopenia Virus (FPLV), Feline Herpesvirus (FHV), and Feline Calicivirus (FCV).

Rinderpest, after being introduced, regulated the wildebeest population, which in turn influenced the dynamics of the entire ecosystem.

The Rinderpest outbreak in the Serengeti resulted in an economic impact of approximately 1.02 billion USD due to the loss of livestock and subsequent famine.

The Rinderpest outbreak caused millions of deaths primarily due to famine, as the disease affected domestic cattle, leading to a significant loss of food resources.

The economic impact of the Rinderpest outbreak in Africa during the late 1800s was approximately 1.02 billion USD.

The Rinderpest outbreak caused millions of deaths in livestock, leading to famine and significant disruption in agricultural practices.

Vaccination against Rinderpest started in 1960 and the disease was declared eradicated in 2011.

No, Rinderpest is not a zoonosis; it primarily affects cattle and does not transmit to humans.

The introduction of the rinderpest virus disrupted the dynamics of the savannah, leading to a cascade effect that included shifts in species distribution and an increase in bushfires.

Rinderpest eradication campaigns contributed to the return of the savannah to its 'natural' condition, reducing bushfires and improving livelihoods.

Rinderpest has a negative impact on wildebeest populations, leading to a decline in their numbers.

Wildebeest have a positive impact on grass, promoting its growth and health within the ecosystem.

Fire has a negative impact on wildebeest and trees, but a positive impact on grass, helping to maintain its growth.

Flying foxes are the natural reservoirs of the Nipah virus. Habitat encroachment and agricultural expansion modified their distribution, leading to increased interactions with domestic animals and humans.

The Nipah virus outbreak in Malaysia resulted in 265 human cases and 105 deaths. Additionally, over 1 million pigs were culled to control the outbreak.

Key factors contributing to the spread of the Nipah virus included:

1. Lack of biosecurity in farms.
2. Overlapping feeding sites of flying foxes and pigs.
3. Habitat encroachment affecting the distribution of flying foxes.

The economic impact of African Swine Fever in Asia includes:

• Over 5 million pigs culled
• Direct costs estimated between 55 to 130 billion US dollars
• Spread to both farmed and wild pigs across 16 countries

• 11 wild pig species endemic to Asia are at risk.
• 3 species from Sulawesi and 1 from Sumatra are of major concern.

Rural families in the region are affected as their income and protein source depend on wild boars, which are threatened by African Swine Fever.

The outbreak of African Swine Fever can disrupt forest dynamics and alter the food web in the region, affecting various species and ecological relationships.

• Hand washing
• Wearing masks

Immunization (vaccination) helps to build immunity against specific infectious diseases, reducing the risk of outbreaks and protecting public health.

• Quarantine: Separating individuals who may have been exposed to an infectious disease.
• Culling: Removing infected animals or individuals to prevent disease spread.

• Antibiotics: Used for bacterial infections.
• Antivirals: Used for viral infections.

Biosecurity consists of the implementation of measures to prevent or restrict the spread of a pathogen. This includes:

• Use of protective equipment
• Sanitation and disinfection of tissues, surfaces, and physical surroundings
• Simple practices like washing hands and covering the mouth when coughing or sneezing.

Immunisation is the process through which the body develops a memory of the immune system to respond effectively to future external aggressions. It helps prevent sickness in previously naïve hosts by preparing the immune system to recognize and combat pathogens more efficiently.

Infection of a naïve host results in sickness, as the immune system has not yet encountered the pathogen. In contrast, infection of an immune host leads to no sickness, as the immune system is already prepared to respond to the pathogen due to prior immunisation.

'Patient Zero' refers to the initial source of the infection, which is crucial in understanding how the disease spreads. Identifying this individual helps in tracing the transmission pathways and implementing control measures.

Unvaccinated cats are more susceptible to infection, leading to higher transmission rates. Infected cats can easily spread the disease to healthy cats, resulting in outbreaks that can escalate quickly due to the lack of immunity in the population.

Visual representations help illustrate complex concepts such as disease transmission dynamics, making it easier to understand how infections spread, the role of 'Patient Zero', and the impact of unvaccinated individuals on overall population health.

'Patient Zero' refers to the first individual infected in an outbreak. Understanding their role is crucial for tracking the spread of disease and implementing control measures. In herd immunity, the presence of vaccinated individuals helps to prevent the spread of infection from Patient Zero to others, thereby protecting the unvaccinated population.

The implementation of isolation measures depends on several factors, including:

• Characteristics of the pathogen
• Animal species and their value
• Social and cultural context
• Economics and politics

Pets must be vaccinated against rabies and spend between 30 and 120 days in isolation.

1. Vaccination of the dog and cat population in the country/region.

2. Population control of free-ranging cats and dogs.

The key strategies include:

1. Elimination of infected birds
2. Reduction of the population on the farm
3. Active surveillance in the surroundings
4. Immunisation of susceptible birds

The key measures include:

1. No Vaccine available for prevention.
2. No treatment for infected pigs.
3. Elimination of all infected and suspected pigs on the farm to control the spread.

Over 70% of terrestrial habitats have been converted to agriculture.

Drivers include changes in wildlife distribution and behavior, intensive food production, and significant profits from wildlife trade, estimated at around $26 billion per year.

Bi-directional adaptation refers to the mutual influence and adjustment between humans and their environment, where both parties evolve and change in response to each other. This can include agricultural practices, settlement patterns, and resource management that reflect the needs and capabilities of both humans and the ecosystem.

Humans and animals have co-existed by forming complex relationships that include:

1. Shared Resources: Both humans and animals rely on the same resources such as food, water, and shelter.
2. Mutual Benefits: Domestication of animals for labor and companionship, while animals benefit from human-provided food and protection.
3. Cultural Significance: Animals play important roles in human culture, religion, and economy, influencing social structures and practices.
4. Ecosystem Balance: The interactions help maintain ecological balance, as humans manage land and resources while animals contribute to soil health and biodiversity.

Approximately 7.9 billion people were living in the world in 2021.

The population density in 2021 was approximately 60 people per km².

The graph shows an upward trend in global population, increasing from approximately 2.5 billion in 1950 to about 7.9 billion in 2021.

Approximately 8 billion people.

About 60 people per km² on average globally.

Countries like China and India are shown in dark brown on the map, indicating they have very high population density.

The production of goods and commodities requires a substantial amount of natural resources, leading to environmental degradation such as deforestation and loss of biodiversity.

By 2030, it is projected that humanity would need 2 Earths to meet the demand for natural resources due to overconsumption.

From 1961 to 2016, the consumption of natural resources increased from 0.74 Earths to 1.6 Earths, indicating a significant rise in resource depletion.

20% of the population consumes 80% of the world's resources, highlighting a disparity in resource consumption.

Overconsumption leads to increased CO2 emissions that exceed the absorption capacity of carbon sinks, and results in deforestation and overfishing, which outpace the regeneration of forests and oceans.

• Deterioration of health systems
• Pause of vaccination campaigns
• Migration to safe places

The 'Spanish' Influenza pandemic spread from the USA into Europe and the world during WWI, highlighting how conflicts can facilitate the spread of infectious diseases.

Key factors contributing to inequity in health care access include:

1. Poverty and hunger, limiting financial resources
2. High costs and unaffordable health care systems
3. Unequal access to vaccines and treatments
4. Displacement and refugee status restricting service access
5. Systemic barriers (e.g., discrimination, lack of infrastructure)

Fear significantly contributes to the spread of disinformation by influencing people's perceptions and reactions to information, making them more susceptible to accepting false narratives.

Critical thinking is essential in navigating the vast amount of information available online, allowing individuals to discern credible sources from misleading ones, especially in health-related matters.

The anti-vaxxer movement is a prime example, as it has led to a resurgence of measles due to the spread of false information regarding vaccine safety.

The four aspects of sustainability are:

1. HEALTH: Prevention of non-communicable diseases such as diabetes, hypertension, dyslipidemia, obesity, and metabolic syndrome.
2. ECOLOGICAL: Maintaining a balance between the consumption of resources and their regeneration.
3. SOCIAL: Ensuring well-being conditions such as safety, health, education, democracy, and justice are equally distributed by class and gender.
4. ECONOMIC: Generating income and work for the sustenance of populations while respecting the ecosystem.