WEEK 1: EMERGING VIRAL DISEASES

Question 1

What are EIDS?

Answer 1

EIDs are infectious diseases that have not occurred in humans before, have occurred previously in humans but affected only small populations in isolated areas, or have occurred in the past but were only recently recognized as distinct diseases caused by infectious agents.

Question 2

What are REIDS?

Answer 2

REIDs are infectious diseases that constituted significant health problems in a particular geographic area or globally during a previous time, then declined greatly, but are now again becoming health problems of major importance.

Question 3

Most EIDs and REIDs have a zoonotic origin. Explain what is meant by this.

How are they transmitted?

Answer 3

The disease has emerged from an animal and crossed the species barrier to infect humans [5]. The majority of these zoonoses come from wildlife, while others originate from domesticated animals and intensive animal farming.

They are transmitted from animals to humans through direct contact, droplets, water, food, vectors, or fomites.

Question 4

Not all EIDs and REIDs are zoonoses. Give other types.

Answer 4

Infections due to several multi-drug resistant organisms, such as vancomycin-resistant Staphylococcus aureus and Candida auris, are considered non-zoonotic EIDs that are related to antibiotic overuse and misuse

Question 5

Outline factors precipitate the occurrence and transmission of EIDs and REIDs

Answer 5

• Expanding human population
• Population aging
• Urbanization
• Globalization
• Climate change
• Poverty
• Social inequality
• Conflicts
• Migration
• Wildlife trade and Consumption
• Industrial livestock production
• Irrational antimicrobial use
• Development of resistance in humans and livestock
• Breaches in implementing public health measures, such as sanitation and vaccination programs.

Question 6

Discuss the impact of EIDS & REIDS.

Answer 6

• Global mortality and morbidity:
• Economic burden:
• There is already a huge, unparalleled in human history, loss of economic well-being and social capital, especially among the weaker sections of societies, such as economically and socially deprived citizens.
• Social and geopolitical implications:
• Education, employment, global poverty, public psychology, tourism and the associated industry, global production, logistics, and global trade have all been negatively affected

Question 7

There is significance for a coordinated and sustained global response to address the threats that EIDs and REIDs pose to humans.

The response should be based on a multifaceted approach, under a One Health perspective, which integrates different disciplines and sectors., including:

Answer 7

veterinary medicine, biology, epidemiology, immunology, human medicine, public health, behavioral and communication science, anthropology, sociology, psychology, education, and others.

Question 8

Outline ways of preventing or detecting EIDS and REIDS at an early stage when more rigorous control options are available.

Answer 8

• Focusing on and investing in proactive and preventive strategies and policies, especially in developing countries where resources are limited.
• Strengthening surveillance
• Rapid risk assessment
• Risk communication

Question 9

Outline newer epidemiological surveillance tools which will greatly facilitate a future response to EIDS and REIDS.

Answer 9

• Artificial intelligence
• Wastewater surveillance
• The evolution of rapid multiplex, and easy to use diagnostics.
• Prompt development and evaluation of novel therapeutics with fewer regulatory, legal, and financial hurdles.

Question 10

What was one of the greatest scientific achievements during the current pandemic?

Answer 10

The record-breaking speed in producing safe and effective vaccines against this novel virus, many of which are based on new technology, that have already saved millions of lives across the world.

Question 11

What is the leading source of emerging viral diseases?

Answer 11

*Zoonotic origin
*From drug resistances

Question 12

What is the mechanism by which a new virus become a cause of disease in human?

Answer 12

*Reactivation of latent infections which were dormant in the body.
*New infection from viruses in the environment

Question 13

Name at least 4 factors that promote the emergence of new viral diseases?

Answer 13

*Migration
*Poverty
*Increase in population
*Aging
*War and conflicts
*Social inequity

Question 14

What steps can be taken to limit emergence of new viral disease?

Answer 14

*Focusing on and investing in proactive and preventive strategies and policies, especially in developing countries where resources are limited.
* Strengthening surveillance
* Rapid risk assessment
* Risk communication

Question 15

Are emerging viral diseases predicted to decline in the future?

Answer 15

No, because the risk factors resulting in their spread keep on happening and the population is increasing.

Question 16

What has been the trajectory in the emergence of past new viral diseases?

Answer 16

• Some of these diseases have caused outbreaks or pandemics.
  *Others have remained sporadic or endemic.

Question 17

Once identified, what are the possible ways that an emerging viral disease may end in a population?

Answer 17

*Some are seasonal such as Influenza
*Some are episodic

*The virus becomes less virulent or transmissible over time and causes milder infections or disappears.

*The population develops immunity through natural infection or vaccination and reduces the spread of the virus.

*The public health measures such as social distancing, mask wearing, testing, tracing and isolation effectively contain the virus and prevent outbreaks.

*The virus adapts to a new host species and jumps from humans to animals or vice versa

Question 18

What are some of the significant vectors for emerging viral diseases?

Answer 18

Some of the significant vectors for emerging viral diseases are mosquitoes and ticks.

They can transmit diseases such as malaria, West Nile fever, dengue fever, Chikungunya fever, Zika virus fever, yellow fever, Japanese encephalitis, leishmaniasis, Lyme disease and tick-borne encephalitis.

Question 19

What is unique about mutation rate of RNA viruses?

Answer 19

One unique feature of RNA viruses is that they have high mutation rates compared to DNA viruses. This is because RNA viruses lack a proofreading mechanism during replication and are more prone to errors.

High mutation rates can help RNA viruses adapt to new hosts and environments, but also pose a risk of extinction if the mutations are deleterious.

The high mutation rates of RNA viruses boost their genetic diversity. Mutations can accumulate rapidly in the viral genome, leading to the generation of diverse viral population.

Question 20

What is required to monitor for emerging and re-emerging viral disease?

Answer 20

*Innate immune sensing and viral evasion strategies are important to understand the biology, immunity, and pathogenesis of the viral infections.

*Continuous genomic surveillance and vector control are essential to prevent and treat those emerging infections.

*Global cooperation and coordination are needed to effectively address and contain infectious disease outbreaks to limit global contagion.

Question 21

When did HIV emerge? DNA or RNA?
Source?
Current status?
Expected long term outcome?

Answer 21

1. 1981, It is an RNA virus.
2. HIV came from a type of virus in chimpanzees called the simian immunodeficiency virus (SIV).
3. The HIV infection is still present, the transmission rate has decreased compared to in the past but there are still some countries with high prevalence due to better medical interventions.
4. The virus will always be a part of human life looking at the fact that its spread is mostly facilitated by human behavior which most people are unwilling to change for the better.

Question 22

Ebola
When did it emerge? DNA or RNA?

Source?

Current status?

Expected long term outcome?

Answer 22

The Ebola virus was first identified in 1976 during two simultaneous outbreaks in Nzara, South Sudan, and Yambuku, Democratic Republic of Congo (formerly Zaire).

Source:

The natural reservoir host of Ebola virus is believed to be fruit bats, particularly the various species of the fruit bat family Pteropodidae. Transmission to humans often occurs through contact with the blood, secretions, organs, or other bodily fluids of infected animals, such as bats, monkeys, gorillas, and chimpanzees. Human-to-human transmission can occur through close contact with the blood, secretions, organs, or other bodily fluids of infected individuals.
Current Status:

As of my last knowledge update in September 2021, Ebola outbreaks continued to occur sporadically in regions of Central and West Africa. Various organizations, including the World Health Organization (WHO), were actively involved in efforts to control and contain these outbreaks.

Expected Long-term Outcome:
The long-term outcome for controlling and eradicating Ebola remains challenging due to its presence in animal reservoirs and the potential for new human outbreaks. Efforts to control Ebola typically involve early detection, isolation and treatment of cases, contact tracing, safe burial practices, and public health education. The development and deployment of vaccines, such as the rVSV-ZEBOV-GP vaccine, have shown promise in reducing the impact of Ebola outbreaks. Long-term success in managing Ebola will depend on sustained surveillance, improved healthcare infrastructure, and international cooperation.

Question 23

Coronavirus
When did it emerge? DNA or RNA?

Source?

Current status?

Expected long term outcome?

Answer 23

SARS-CoV-2, which causes COVID-19, emerged in late 2019 in Wuhan, China.
Genetic Material:

Coronaviruses are RNA viruses. They have a single-stranded, positive-sense RNA genome. The genetic material in coronaviruses is RNA, not DNA.
Source:

Coronaviruses have zoonotic origins, meaning they typically originate in animals and can be transmitted to humans. The exact animal source of SARS-CoV-2 is still under investigation, but it is believed to have originated in bats and possibly passed through an intermediate host species before infecting humans.
Current Status:

As of my last knowledge update in September 2021, the COVID-19 pandemic, caused by SARS-CoV-2, was ongoing worldwide. Vaccination campaigns were underway in many countries, and various public health measures were in place to control the spread of the virus. It’s important to note that the situation with COVID-19 continues to evolve, and it’s best to refer to reliable sources such as the World Health Organization (WHO) or the Centers for Disease Control and Prevention (CDC) for the most current information.
Expected Long-term Outcome:

The long-term outcome of the COVID-19 pandemic remains uncertain. However, it’s expected that over time, through vaccination and natural immunity, the impact of the disease will be reduced. The pandemic may transition into an endemic phase, where the virus continues to circulate but at lower and more manageable levels. The development and distribution of effective vaccines are key tools in controlling the spread of the virus in the long term. Public health measures and surveillance will also remain important for managing and responding to outbreaks.

Question 24

Zika virus

Source?

Current status?

Expected long term outcome?

Answer 24

Source:

Zika virus was first identified in Uganda in 1947 in a monkey. The first human case was reported in 1952. Zika is primarily transmitted to humans through the bite of infected Aedes mosquitoes, particularly Aedes aegypti and Aedes albopictus. These mosquitoes are found in various regions around the world.
Current Status:

As of my last knowledge update in September 2021, Zika virus was still a concern in several countries and regions, particularly in tropical and subtropical areas where Aedes mosquitoes are prevalent. Outbreaks and cases of Zika were reported in various parts of the world. However, the level of concern and public health response had varied by region. Due to the potential for birth defects, Zika remained a focus for health authorities and pregnant women. Travel advisories and guidance were issued for individuals traveling to affected areas. The situation with Zika may have evolved since that time, so it is important to consult up-to-date sources, such as the World Health Organization (WHO) or the Centers for Disease Control and Prevention (CDC), for the latest information.
Expected Long-term Outcome:

The long-term outcome of Zika virus is challenging to predict. It is likely to continue circulating in regions where Aedes mosquitoes are present. However, efforts to control Zika include mosquito control measures, public health education, and vaccine development. Over the long term, a vaccine could play a crucial role in reducing the impact of the virus. Preventive measures, such as avoiding mosquito bites, particularly for pregnant women, will continue to be important to reduce the risk of birth defects. Additionally, public health surveillance and monitoring will help track and respond to outbreaks. It’s important to note that the long-term outlook for infectious diseases like Zika can vary by region and is subject to change based on public health interventions and other factors.

Regenerate

Question 25

Influenza
When did it emerge? DNA or RNA?

Source?

Current status?

Expected long term outcome?

Answer 25

Notable pandemics include the 1918 Spanish flu, the 1957 Asian flu, the 1968 Hong Kong flu, and others. Influenza viruses have been circulating and evolving for a long time, leading to various strains.
Genetic Material:

Influenza viruses have a segmented negative-sense RNA genome. They do not have DNA as their genetic material. The RNA segments encode the virus’s proteins.
Source:

Influenza viruses primarily infect birds and, to a lesser extent, pigs. They can jump from animals to humans, leading to human influenza outbreaks. Waterfowl, especially wild ducks, are natural reservoirs for many influenza A viruses.
Current Status:

Influenza is a seasonal respiratory illness, and different strains of the virus continue to circulate in humans and animals. The global status of influenza varies from year to year. Annual vaccination campaigns target the predominant strains of the virus to reduce its impact. Influenza is a significant public health concern, but its status and prevalence fluctuate depending on the specific strains in circulation.
Expected Long-term Outcome:

Influenza is expected to remain a recurring respiratory infection in the long term. Vaccination and antiviral drugs are key tools for controlling and mitigating the impact of seasonal influenza. Researchers continually monitor and adapt the composition of flu vaccines to match the strains expected to circulate in a given flu season. In the long term, research and surveillance efforts will continue to improve our ability to respond to influenza outbreaks and to develop new strategies for prevention and treatment. Public health measures, such as hygiene and social distancing, will also play a role in controlling the spread of the virus. It’s important to note that the specific strains of influenza in circulation and their impact can vary from year to year.

Question 26

Polio
When did it emerge? DNA or RNA?

Source?

Current status?

Expected long term outcome?

Answer 26

Polio has likely been in existence for thousands of years, but the recognition and documentation of the disease date back to ancient civilizations. The modern understanding of polio and its causative agents, the polioviruses, developed in the late 19th and early 20th centuries. Major outbreaks occurred in the 20th century, leading to intensified efforts to develop vaccines. The inactivated polio vaccine (IPV) was introduced in the 1950s, and the oral polio vaccine (OPV) in the 1960s, leading to a significant reduction in cases.
Genetic Material:

Polioviruses are single-stranded RNA viruses. They do not have DNA as their genetic material.
Source:

Polioviruses are transmitted through the fecal-oral route, primarily via contaminated water and food. The virus primarily infects the human gastrointestinal tract and can enter the central nervous system, leading to paralysis.
Current Status:

Great progress has been made in the global eradication of polio. As of my last knowledge update in September 2021, cases of wild poliovirus were at historic lows, and the disease was endemic in only a few countries. This achievement was the result of extensive vaccination campaigns and public health efforts. However, there were still challenges in reaching all children with vaccines, and vaccine-derived poliovirus outbreaks were a concern. The situation with polio may have evolved since then, and it’s important to refer to organizations like the World Health Organization (WHO) for the latest information.
Expected Long-term Outcome:

The long-term goal for polio is its global eradication. Efforts are focused on eliminating all remaining cases of wild poliovirus and stopping the circulation of vaccine-derived polioviruses. Once eradication is achieved, vaccination can be discontinued. However, challenges include vaccine access, vaccine hesitancy, and surveillance to detect and respond to cases. In the long term, polio eradication would be a major public health achievement, similar to the eradication of smallpox. Continual monitoring and vaccination for a period even after eradication will be required to prevent any resurgence of the disease.

Question 27

Monkeypox
When did it emerge? DNA or RNA?

Source?

Current status?

Expected long term outcome?

Answer 27

Emergence:

Monkeypox was first identified in 1970 when outbreaks occurred in remote villages in Central Africa, including the Democratic Republic of Congo (DRC). The disease was named due to its similarity to smallpox and its initial transmission from animals to humans. The emergence of monkeypox was relatively recent in the medical literature.
Genetic Material:

The monkeypox virus has a double-stranded DNA genome. This distinguishes it from some other viruses like Ebola and Zika, which have RNA genomes.
Source:

The natural reservoir hosts of the monkeypox virus are believed to be various types of rodents. Transmission to humans typically occurs through close contact with these animals, their bodily fluids, or through consumption of undercooked meat. Human-to-human transmission is also possible, but it is less efficient than with diseases like smallpox.
Current Status:

Monkeypox is a rare disease, and outbreaks have occurred sporadically in Central and West Africa. The virus is not typically endemic in the United States or many other parts of the world. Cases of monkeypox outside of Africa are infrequent and often associated with travel to or from affected regions. The situation with monkeypox can vary, and local public health agencies and the World Health Organization (WHO) monitor outbreaks.
Expected Long-term Outcome:

The long-term outcome of monkeypox depends on continued surveillance, public health measures, and research. In the long term, efforts will continue to focus on prevention, early detection, and control of outbreaks. There is no specific antiviral treatment for monkeypox, so vaccination and containment measures are crucial. The virus will likely continue to circulate in wildlife populations in endemic regions, and sporadic outbreaks may occur. Public health measures and surveillance are essential for minimizing the impact of the disease in affected regions and for preventing its spread to other parts of the world.