Course:CONS200/2024WT1/Zoonotic disease transfer between wild and domesticated animals in sub-Saharan Africa

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The spread of zoonotic diseases across wild and domesticated animals has plagued communities for hundreds of years, though over the past two decades, there has been a resurgence of epic proportions.[1] Zoonotic diseases are caused by harmful germs such as viruses, bacteria, parasites or fungi and are transmitted between animals and humans or vice versa.[2] These diseases include but are not limited to, Rabies, SARS-CoV-2, Ebola, Dengue, Leptospirosis and Yellow Fever.[3] There are numerous opportunities for transmission between animals and humans directly, through contact with bodily fluids such as urine, blood, or feces, or indirectly through contact with environments and surfaces that are often inhabited by carriers of these diseases.[4] Interactions between humans and domestic or wild animals are plentiful across Sub-Saharan Africa (SSA), as animal husbandry accounts for over 40% of the continent's gross domestic product, and is a major driver of local and regional economies.[5]

A recent study by Ateudjieu et al. found that these diseases have been reported in 26 countries in SSA affecting 28,934 individuals, and causing 1182 deaths between 2020 and 2022.[5] These findings are critical for informing relevant organizations to closely monitor zoonotic diseases and prepare for imminent outbreaks. Numerous factors contribute to the spread of zoonotic diseases such that future projections and estimated repercussions on individuals, communities and nations are widely disputed. Factors contributing to the uprise in zoonotic disease vary, but climate change is exacerbating all possible means of transmission.[1] Global increases in industrialization and urbanization are introducing new complexities as this increases interspecies interactions and thereby transmission opportunities.[6] As climate change progresses, reducing biodiversity across landscapes greatly increases the transmission of both new and established zoonotic pathogens.[7]

Preparedness

The World Health Organization is a specialized agency of the United Nations composed of 194 member states.[8]

Outbreaks of zoonotic diseases produce dire consequences in large areas in little time and have adverse impacts on health, commerce, trade, and livelihood.[9] The overwhelming presence and abundance of these diseases demand preparedness not only throughout SSA but across the globe. At present, numerous countries are becoming well-equipped in the identification of zoonotic diseases, but measures need to be taken to improve not only the response of the region to these outbreaks but also their prevention of them happening in the first place.[9]

Current strategies to mitigate these effects are fragmented and often unattainable due to a lack of policy and resources, especially as solution implementation and the prompt movement of resources are critical.[9] However many countries are improving their preparedness and detection regimes which will benefit outbreak mitigation,[9] but still need adequate governance to prevent the transmission of zoonotic diseases altogether. Moving forward, public health organizations are proposing mitigating wild and domesticated animal interactions, increased monitoring of early effects in humans, and the development of strict policies before and in response to an outbreak.[9] However, as this is a global issue, the implementation of these solutions has proven very challenging.

One Health Initiative

One of the most promising approaches for preparing and preventing zoonotic disease transmission has been put forward by the World Health Organization (2017) called One Health, aiming to approach health safety for humans and animals through interdisciplinary environmental approaches.[10] One Health was designed to create joint responses to health threats from local to global levels by integrating governments, researchers, and communities to produce risk-reducing habits[10]; this approach is critical for areas like SSA with large socioeconomic inequalities that lack sufficient infrastructure for disease management.[11] The African Union has endorsed a One Health approach by raising awareness, gathering data and promoting evidence-based policies to improve human, animal and environmental health, and implementing over ten disease prevention programs.[12]  The Africa Centres for Disease Control and Prevention have begun applying coordinated surveillance systems to respond quickly and effectively to disease outbreaks.[12] Additionally, the Inter-African Bureau for Animal Resouces is striving to meet WHO’s recommendation of maintaining 70% vaccination coverage in dogs to eliminate the transfer of rabies[11] which is almost 100% fatal post-transmission.[13] These interdisciplinary transboundary solutions are critical in mitigating zoonotic diseases in SSA which continue to threaten local, regional and global health, security and economies.[10]

Origins

Agricultural Revolution

Depiction of ancient Egyptian farmers threshing grain with oxen, illustrating early agricultural practices.

Epidemics and pandemics have always been part of human history and development.[14] Some scholars believe that epidemics were rare or not present in traditional hunting and gathers, as there were no significant developments in domestication of wild animals during the period.[15] However, zoonotic epidemics became more likely to happen after the Agricultural Revolution 10,000 years ago.[1] At that period, larger social communities and farming practices expanded the opportunities for humans to be exposed to new pathogens.[1] Factors such as unsanitary conditions, frequent travel between human communities, and trade, further contributed to likelihood of these epidemics taking place.[1]

Modern History

Major epidemics in modern history have been attributed to zoonotic origins. For instance, the 1918 H1N1 Flu Pandemic (also known as Spanish Flu) is believed to have emerged in 1917 when a human acquired components of an avian virus. This specific virus then infected pigs and subsequently humans again, initiating the highly contagious pandemic.[1] From 1918 to 1919, close to a third of the global population was infected by the H1N1 virus and an estimated 50 to 100 million died from the disease in that period.[15]

Impacts

Africa has the fastest-growing and youngest human population of the world.[16] Africa's rapid population growth and urbanization are transforming its landscapes and ecosystems, driving demand for natural resources and food.[16] These changes are increasing interactions between humans, livestock, and wildlife, creating conditions that facilitate the emergence and spread of zoonotic diseases.[16] From rabies to Ebola and Yellow Fever, zoonotic diseases have profound impacts on public health, economies, and societies.[16] Understanding these diseases, their transmission pathways, and their effects is critical for developing prevention and response strategies, and avoiding global pandemics.[16]

Rabies

Electron micrograph imagery of rabies virus particles replicating inside a cell.

Rabies is a zoonotic viral disease that affects the central nervous system of mammals.[17] It usually spreads from animals through bites, scratches, and open mucosa.[17] Once clinically signifcant symptoms appear, rabies is fatal in 100% of cases.[17] Despite being entirely preventable by vaccination, it continues to affect over 150 countries, with the highest burden in Asia and Africa, where it is considered a neglected tropical disease.[17]

Rabies is a devastating zoonotic disease with significant global public health, economic, and social consequences.[17] Globally, rabies causes approximately 59,000 deaths annually, with children under 15 making up 40% of fatalities.[17]

Rabies imposes a global economic burden of approximately $8.6 billion annually, encompassing medical expenses, lost productivity, and the indirect costs of psychological trauma.[17]

Doctors of the World holding centre for Ebola patients in Kuala, Sierra Leone.

Ebola

Ebola is a severe and often fatal zoonotic disease caused by orthoebolaviruses, a group of viruses primarily found in sub-Saharan Africa.[18] The virus is introduced into human populations through contact with infected animals such as bats, chimpanzees, or antelopes and spreads between humans via direct contact with bodily fluids, contaminated objects, or improperly handled bodies during burial practices.[19]

Ebola has a high-mortality rate that can reach 80-90% without treatment.[18] The disease must be detected early in order to provide effective care.[18] Ebola outbreaks have led to devastating consequences in affected communities, including high mortality rates, overwhelming healthcare infrastructure, and economic disruption.[18]

Leptospirosis

Cattle and livestock are the primary vectors of the Leptospira bacterium.

Leptospirosis is a zoonotic disease caused by the Leptospira bacterium, posing significant risks to humans and animals.[20]

Each year, approximately 1 million cases of leptospirosis occur globally, leading to nearly 60,000 deaths.[20] Its impacts are amplified during natural disasters like hurricanes or floods, as contaminated water and soil become widespread, increasing exposure risks.[20]

Livestock, particularly cattle, are significant reservoirs, carrying multiple serovars of Leptospira, which impacts their productivity through decreased milk yield and increased reproductive failures.[21]

Mosquito-Borne Diseases

The African continent carries the largest mosquito-borne disease (MBD) burden in the world.[22] There are at least 151 known mosquito-borne-pathogen species that affect vertebrates.[22] The majority are maintained in wild host reservoirs and can sometimes be transmitted between humans.[22]

Aedes aegypti is the main vector species of Dengue fever.

Dengue

Dengue, often referred to as break-bone fever, is a zoonotic infection transmitted to humans through the bite of infected female mosquitoes, primarily of the Aedes aegypti species.[23] Dengue is endemic in over 100 countries, with an estimated 100-400 million infections annually.[23] While many dengue infections are asymptomatic or result in mild illness, some cases progress to severe dengue, which can cause life-long consequences and even death.[23]

Native to the Atlantic Forest, Golden Lion Tamarins (Leontopithecus rosalia) are often tracked as an early warning system for Yellow Fever outbreaks in South America.[24]

Countries with fragile health system, already impacted by challenges such as the COVID-10 pandemic and humanitarian crises, face significant difficulties in managing dengue outbreaks.[23]

Yellow Fever

Yellow fever is a mosquito-borne virus transmitted by the bites of infected Aedes spp. and Haemagogus spp. mosquitoes.[25] There is no specific anti-viral drug for Yellow Fever, however, a single dose of vaccine is sufficient to achieve life-long protection.[25] There are 34 countries in Africa and 13 countries in Latin America that are endemic to the disease.[25]

The health burden of Yellow Fever in Africa are estimated to cause 84,000 to 170,000 of severe cases and 29,000 to 60,000 deaths in 2013.[25]

Mpox

Mpox, formerly known as Monkeypox, is a zoonotic viral disease caused by the Monkeypox virus, an orthopoxvirus.[26] Mpox is endemic to Central and West Africa, with two distinct clades: the West African clade (Clade II) and the Central Basin clade (Clade I).[27] Clade II has a case fatality rate below 1%, while Clade I can reach up to 11%, particularly in children.[27] The natural reservoir of Mpox is unknown, although small mammals are susceptible to infection.[28]

The cessation of smallpox vaccination after its eradication has allowed Mpox to gain clinical relevance, particularly in endemic regions of sub-Saharan Africa.[29] Since 2022, a global outbreak involving the less fatal variant of Clade II has been reported. [28]

COVID-19

COVID-19 (also known as Coronavirus disease) is a zoonotic infection caused by the virus SARS-CoV-2.[30] The COVID-19 pandemic highlighted both the advancements and limitation of modern medical science. Remarkably, the first SARS-CoV-2 vaccine was developed within a year from the start of the pandemic.[31] The illness was declared a pandemic on March 11, 2020, by the World Health Organization.[32]

Human and Economic Impacts

According to the World Health Organization, 7,072,509 deaths have been confirmed as of November, 2024, with over 700 million infection cases worldwide.[33]

Number of COVID-19 Deaths, Cases, Reported to the WHO (cumulative total)[33]
Country World U.S Brazil India Russia Mexico U.K. Peru Italy Germany France
Deaths 7.1M 1.2M 702K 534K 404K 335K 232K 221K 198K 175K 168K
Cases 777M 103M 37.5M 45M 24.6M 7.6M 25M 4.5M 26.8M 38.4M 39M
Canadian Prime Minister Justin Trudeau receiving his initial dose of the AstraZeneca COVID-19 vaccine on April 23, 2021, at a clinic in Ottawa, Canada.

The COVID-19 pandemic significantly affected mental health and economic systems worldwide. Young adults (ages 18 to 29) experienced heightened levels of anxiety, depression, and distress due to the uncertainty and isolation caused by the pandemic. [34]

Economically, the pandemic disrupted globalization, accelerating a shift towards regional trade and smaller economies.[35] These changes are particularly relevant for the discussion of zoonoses in Africa, where growing urbanization and globalization have increased the chances of human-wildlife interactions, creating conditions for zoonotic spillovers and potentially the next pandemic.[16]


Transmission

Urbanization and Deforestation

Expansion of farmland in the Amazon Rainforest in Brazil.

The transmission of zoonotic diseases is initiated by the contact of non-human animals in contact with humans with the spreading of a variety of pathogens. Although zoonotic diseases have recently become more prevalent, the spread of zoonotic diseases, otherwise known as “zoonotic spillovers,”[5] has not been uncommon in human history and predates our most recent century. There has been exponential growth of frequency in diseases such as Rabies, SARS-CoV-2, Ebola, Dengue, and Yellow Fever[3] due to several ecological, social, and environmental factors in the last two centuries.[1] An example of an ecological factor is the alteration or destruction of habitat due to urbanization and deforestation.[36] Humanity’s shift onto more rural areas as a cause of expansion from urbanization has increased the number of humans in areas that would typically contain animal populations, which has resulted in higher chances of these interactions with animals carrying the disease.[37] Further, this can account for the destruction of habitat, where urbanization and deforestation have left several animal species without where several animal populations and species have been left displaced. According to Fong, this can be seen in how “developmental progress with clearing of forests for new roads, residences, towns, and farmlands impinge on wildlife ecology.”. As a result of these factors, both animals and humans have begun to cross over into each other’s habitats, creating a more frequent spread of pathogens.[36] Though direct human interference enhanced this ecological factor, it can also be accounted for by climate change. The shift in the environment, and subsequently the climate, from human impact has altered the course of different environments from weather, flora, and fauna.[1] As a result, climate change has played a part in the deforestation and destruction of habitat, which directly links to how carrier animals have increased contact with humans.

Trade and Consumption

Slaughter market in Onitsha, Nigeria.

The social impacts from human activities such as cultural and agricultural practices have furthered the spread as well. An example of this is markets selling produce or meats that contain diseases such as salmonella and tuberculosis,[38] which is otherwise known as “wildlife trade and consumption”[37] of zoonotic diseases. As markets selling contaminated produce or animal meat increase, so do the transmissions of diseases from ingesting animals contaminated foods. An example of this can be seen in the spread of salmonella in regions of Kenya, where several outbreaks have been found in pork markets. As a result, this increase of zoonotic diseases has been supported by the direct link between human dietary choices and disease transmission.[37]

Solutions

Volunteer in a clinical trial receiving the Ebola vaccine in Liberia, 2017.

According to the World Health Organization (WHO), “a coordinated response involving multiple sectors is essential to prevent and control zoonotic diseases.”[39] This includes implementing vaccines to livestock and wildlife, as well as communities in areas that are highly affected,[40] which will limit the spread from human interactions with animal populations. Further, organizations have been attempting to increase supervision and monitoring of our interactions with these animals to pinpoint which are carriers and ensure that proper hygienic measures are taken around them.[9] In addition to safe animal interactions, these hygienic practices are also implemented in the handling of foods in markets. This includes strengthening the cleanliness of areas that focus on slaughtering, transporting, and selling meats by providing more sanitization for the workers as well as the areas. Despite these solutions, zoonotic diseases continue to spread and affect communities across the globe.[26] To combat the rising threat of zoonotic diseases, a multi-faceted approach that incorporates both preventative and reactive measures is essential. To see change on a global scale, there will need to be a grander contribution from both governments and communities in the form of policies and laws.

Aggregating Factors: Climate Change

Impacts

Projections show that climate change will impact both the expansion and severity of animal-borne diseases.[41] Any climate-related factors that influence the interactions between the host animal and the infected animal will also affect the spread and effect of zoonotic diseases.[42] The effects of climate change, including patterns such as changing rainfall, increasing temperatures, and longer summer seasons, are expected to increase the susceptibility of livestock to zoonotic diseases spread by wild animal populations through various mechanisms.[42] Increasing temperatures lead to drought and the increase in prevalence and severity of wildfires, which alter the distribution of disease hosts.[42] Global temperature changes are altering habitats worldwide, meaning pathogen-spreading species such as Aedes mosquitos exist in regions where they have not been seen before.[41]

Global Increase in Industrialization and Urbanization

Lekki Conservation Centre (LCC) surrounded by urban sprawl in Lekki, Nigeria.

Industrial expansion for the construction of urban centers, as well as logging for agriculture destroy habitats and act to displace wildlife. This results in animals, including bats, rodents, and primates, moving closer to human habitats.[43] This increases the likelihood of human-wildlife interactions, as well as interactions between wild and domesticated animals. For example, the West African ebola virus outbreak, beginning in 2013, was linked to human encroachment into forests, increasing their exposure to infected fruit bats.[44] Industrial farming has increased the spread of diseases, as animals are forced together into confined spaces, making disease transmission among them much more swift.[43] The proximity of humans working with these animals increases the risk of zoonotic disease transmission from animals to people. Urbanization, a trend which concentrates larger human populations into dense living areas, has allowed for overcrowding and faster human-to-human spread of zoonotic diseases which have spilled over from animal populations. Industrialization and globalization has allowed for the global spread of zoonotic diseases across international borders. Infected animals, contaminated animal products, and people can transport these diseases across borders, introducing them to areas and populations with no resistance.[45]

Biodiversity Loss

Illustration of the Large Sloth Lemur (Palaeopropithecus ingens), listed as extinct by the IUCN in 2021.

Biodiversity loss has been found to have an impact on the spread of zoonotic diseases. The general trend is that the transmission of a pathogen increases as diversity declines.[7] This is seen through the “dilution effect”, in which a diversity of species in a community will dilute the impact that a disease-infected host causes on the community. When biodiversity declines, the impacts of the host species will be much more prevalent throughout the community.[7] The species most impacted by a decline in biodiversity tend to be larger bodied and have slower life histories, while smaller species with fast life histories will generally increase in abundance.[46] Fast lived and smaller species are more likely to be the carriers and spreaders of zoonotic diseases, and therefore biodiversity loss leads to an overall increasing trend in disease prevalence in communities.[7] Reservoir species which tend to carry diseases have also been found to be less abundant in areas with less human disturbance. This trend shows that human impacts and disturbance increase biodiversity loss and the prevalence of zoonotic pathogens.[7]

Animal Resilience

Climate change effects also impact animal’s immune responses to combat zoonotic diseases. Increasing temperatures causes heat stress, which can result in immune responses leading to morbidity and increased chance of death.[42] Heat stress has been shown to reduce both resistance and productivity in a wide range of domestic species.[42]

Examples

Electron micrograph image of a tissue infected by Rift Valley fever.

A significant example of a disease impacted by climatic changes is Rift valley Fever (RVF), a zoonotic disease impacting mainly domesticated sheep and goats in Eastern regions of Africa. Irregular and heavy periods of rainfall in recent decades have caused dormant eggs of infected Aedes carrier mosquitoes to hatch and spread the disease at much higher rates among livestock than during periods of regular climates in the region.[42] The dense vegetation which generates after heavy rainfall provides nesting sites for disease-spreading species, further impacting the spread.[41] Increasing rates of RVF have also been observed in areas of North and West Africa where increased rainfall has not been observed. Increasing drought as a result of climate change has resulted in the need for more irrigation for agriculture, providing new breeding sites for the insects and making these areas more susceptible to the disease.[42]

Another trend which has been observed throughout sub-Saharan Africa is the effect of rising temperatures due to climate change on the prevalence of ticks. High temperatures shorten their life cycles, yet also increase their reproductive rates.[42] While higher mortality rates are limiting tick habitats in some areas, their habitat is also expanding to include regions with little to no threat of tick borne illnesses previously.[42]

Conclusion

The spread of zoonotic diseases has been a persistent challenge throughout human history, yet modern developments such as climate change, urbanization, and biodiversity loss have magnified their frequency and severity.[41] These diseases not only threaten public health but also disrupt economies, trade, and ecosystems on a global scale. While advancements in monitoring, vaccination, and interdisciplinary approaches like the One Health Initiative offer promising pathways for mitigation, regions of sub-Saharan Africa face severe limitations due to resource-scarcity and poverty.[10] The unique challenges that sub-Saharan countries face highlight the need for specifically taiolred solutions that prioritize infrastructure, education, and policy reform. Ultimately, global collaboration and integrating local efforts is crucial to reduce the burden of zoonotic diseases, specially in times where these diseases emerge and spread more quickly around the world.

References

  1. ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 Fong, I. W. (2017). Emerging Zoonoses: A Worldwide Perspective. Toronto: Springer. ISBN 978-3-319-50890-0.
  2. ↑ Centers for Disease Control and Prevention (November 3, 2024). "About Zoonotic Diseases".
  3. ↑ 3.0 3.1 Aliaga-Samanez, Alisa; Romero, David; Murray, Kris; Cobos-Mayo, Marina; Real, Raimundo; Olivero, Jesus (2024). "Climate Change is Aggravating Dengue and Yellow Fever Transmission Risk". Ecography. 10: e06942.
  4. ↑ Centers for Disease Control and Prevention (November 3, 2024). "About Zoonotic Diseases".
  5. ↑ 5.0 5.1 5.2 Ateudjieu, Jerome; Fodjo, Joseph Nelson Siewe; Ambomatei, Calson; Tchio-Nighie, Ketina Hirma; Bissek, Anne-Cecile Young Kanyi (2023). "Zoonotic Diseases in Sub-Saharan Africa: A Systematic Review and Meta-Analysis". Zoonotic Diseases. 3: 251–265.
  6. ↑ Malik, Yashpal S.; Milton, A. Arun Prince; Ghatak, Sandeep; Ghosh, Souvik (2021). Role of Birds in Transmitting Zoonotic Pathogens. Singapore: Springer. ISBN 978-981-16-4553-2.
  7. ↑ 7.0 7.1 7.2 7.3 7.4 Keesing, Felicia (2021). "Impacts of biodiversity and biodiversity loss on zoonotic diseases". Proceedings of the National Academy of Sciences.
  8. ↑ World Health Organization (WHO). "Who we are". Retrieved December 2024. Check date values in: |access-date= (help)
  9. ↑ 9.0 9.1 9.2 9.3 9.4 9.5 World Health Organization (WHO) (2014). "Zoonotic disease: emerging public health threats in the Region". World Health Organization. Retrieved November 2024. Check date values in: |access-date= (help)
  10. ↑ 10.0 10.1 10.2 10.3 "One Health". World Health Organization. 21 September 2017.
  11. ↑ 11.0 11.1 Meseko, Clement (22 June 2022). "How a One Health approach can mitigate the social and economic burdens of zoonoses in Africa". PreventionWeb.
  12. ↑ 12.0 12.1 Alimi, Yewande (2023). "Strengthening coordination and collaboration of one health approach for zoonotic diseases in Africa". One Health Outlook – via PubMed Central.
  13. ↑ "Rabies". World Health Organization. 5 June 2024.
  14. ↑ Vögele, Jörg (2021). "Epidemics and Pandemics – the Historical Perspective. Introduction". Historical Social Research. 33: 7–33 – via JSTOR.
  15. ↑ 15.0 15.1 Mamelund, Svenn-Erik (2008). "Influenza, Historical". International Encyclopedia of Public Health.
  16. ↑ 16.0 16.1 16.2 16.3 16.4 16.5 International Food Policy Research Institute (IFPRI) (April 8, 2020). "Africa's growing risk of diseases that spread from animals to people". International Food Policy Research Institute. Retrieved December 2024. Check date values in: |access-date= (help)
  17. ↑ 17.0 17.1 17.2 17.3 17.4 17.5 17.6 World Health Organization (WHO) (June 5, 2024). "Rabies". Retrieved December 2024. Check date values in: |access-date= (help)
  18. ↑ 18.0 18.1 18.2 18.3 U.S. Centers for Disease Control and Prevention (CDC). "Ebola Disease Basics". CDC. Retrieved December 2024. Check date values in: |access-date= (help)
  19. ↑ World Health Organization (WHO) (April 20, 2023). "Ebola virus disease". Retrieved December 2024. Check date values in: |access-date= (help)
  20. ↑ 20.0 20.1 20.2 U.S. Centers for Disease Control and Prevention (CDC). "About Leptospirosis". CDC. Retrieved December 2024. Check date values in: |access-date= (help)
  21. ↑ Allan, Kathryn J.; Biggs, Holly M.; Halliday, Jo E. B.; Kazwala, Rudovick R.; Maro, Venance P.; Cleaveland, Sarah; Crump, John A. (2015). "Epidemiology of Leptospirosis in Africa: A Systematic Review of a Neglected Zoonosis and a Paradigm for 'One Health' in Africa". PLoS Neglected Tropical Diseases. 10: e0004552.
  22. ↑ 22.0 22.1 22.2 Lehmann, Tovi; Kouam, Cedric; Woo, Joshua; Diallo, Mawlouth; Wilkerson, Richard; Linton, Yvonne-Marie (2023). "The African mosquito-borne diseasosome: geographical patterns, range expansion and future disease emergence". Proceedings of the Royal Society B. 290: 20231581.
  23. ↑ 23.0 23.1 23.2 23.3 World Health Organization (WHO) (April 23, 2024). "Dengue and severe dengue". Retrieved December 2024. Check date values in: |access-date= (help)
  24. ↑ Dietz, James M.; Hankerson, Sarah J.; Alexandre, Brenda Rocha; Henry, Malinda D.; Martins, Andreia; Ferraz, Luis Paulo; Ruiz-Miranda, Carlos (2019). "Yellow fever in Brazil threatens successful recovery of endangered golden lion tamarins". Scientific Reports. 9: 12926.
  25. ↑ 25.0 25.1 25.2 25.3 World Health Organization (WHO) (May 31, 2023). "Yellow Fever". World Health Organization. Retrieved December 2024. Check date values in: |access-date= (help)
  26. ↑ 26.0 26.1 World Health Organization (WHO). "Mpox". World Health Organization. Retrieved December 2024. Check date values in: |access-date= (help)
  27. ↑ 27.0 27.1 U.S. Centers for Disease Control and Prevention (CDC). "About Mpox". Retrieved December 2024. Check date values in: |access-date= (help)
  28. ↑ 28.0 28.1 World Health Organization (WHO) (August 26, 2024). "Mpox". World Health Organization. Retrieved December 2024. Check date values in: |access-date= (help)
  29. ↑ Moore, Marlyn J.; Rathish, Balram; Zahra, Farah (2023). Mpox (Monkeypox). Treasure Island (FL): StatPearls [Internet].
  30. ↑ World Health Organization (WHO). "Coronavirus disease (COVID-19)". Retrieved December 2024. Check date values in: |access-date= (help)
  31. ↑ Chakraborty, Chiranjib; Bhattacharya, Manojit; Dharma, Kuldeep (2023). "SARS-CoV-2 Vaccines, Vaccine Development Technologies, and Significant Efforts in Vaccine Development during the Pandemic: The Lessons Learned Might Help to Fight against the Next Pandemic". Vaccines. 11: 682.
  32. ↑ World Health Organization (WHO). "Coronavirus disease (COVID-19) pandemic". Retrieved December 2024. Check date values in: |access-date= (help)
  33. ↑ 33.0 33.1 World Health Organization (WHO) (December 2024). "WHO COVID-19 dashboard". Retrieved December 2024. Check date values in: |access-date= (help)
  34. ↑ Dhiman, Monita (2024). "Challenges and Opportunities for Youth". In Sobti, R. C.; Sobti, Vipin; Aggarwal, Monika (eds.). The Impact of the COVID-19 Pandemic on People and Their Lives: Socio-Political and Economic Aspects. Routledge. pp. 162–172. ISBN 978-1-003-33336-4. line feed character in |chapter= at position 29 (help)
  35. ↑ Yadav, D. K. (2024). "Impact of the COVID-19 Pandemic on Macroeconomic Indicators: A Comparative Study of Developed and Developing Countries". In Sobti, R. C.; Sobti, Vipin; Aggarwal, Monika (eds.). The Impact of the COVID-19 Pandemic on People and Their Lives: Socio-Political and Economic Aspects. New York, NY: Routledge. pp. 207–229. ISBN 978-1-003-33336-4.
  36. ↑ 36.0 36.1 White, Rebekah J.; Razgour, Orly (2020). "Emerging zoonotic diseases originating in mammals: a systematic review of effects of anthropogenic land-use change". Mammal Review.
  37. ↑ 37.0 37.1 37.2 Smith, Katherine F. (2012). New Directions in Conservation Medicine: Applied Cases of Ecological Health. Oxford University Press. pp. 151–159.
  38. ↑ Westhuizen, Cornelius G. van der; Burt, Felicity J.; Heerden, Nina van; Zyl, Willie van; Anthonissen, Tonia; Musoke, Jolly (2023). "Prevalence and occupational exposure to zoonotic diseases in high-risk populations in the Free State Province, South Africa". Frontiers in Microbiology. 14.
  39. ↑ "Zoonoses". World Health Organization. 29 July 2020.
  40. ↑ "Enhancing preparedness to tackle rising zoonotic diseases in Africa". World Health Organization. 4 April 2023.
  41. ↑ 41.0 41.1 41.2 41.3 Rupasinghe, Ruwini (2021). "Climate change and zoonoses: A review of the current status, knowledge gaps, and future trends". PubMed – via national Library of Medicine.
  42. ↑ 42.0 42.1 42.2 42.3 42.4 42.5 42.6 42.7 42.8 Magiri, Royford (2020). "Impact of Climate Change on Animal Health, Emerging and Re-emerging Diseases in Africa". SpringerNature: 1–18.
  43. ↑ 43.0 43.1 Reyes, Raquel (2012). "Urbanization and Infectious Diseases: General Principles, Historical Perspectives, and Contemporary Challenge". PubMed Central: 123–146.
  44. ↑ Boisen, M.L. (2016). "Epidemiology and Management of the 2013–16 West African Ebola Outbreak". Annual Review of Virology. 3: 147–171.
  45. ↑ Anugwom, Edlyne E. (2023). Integrated Science of Global Epidemics. Springer, Cham. pp. 307–328. ISBN 978-3-031-17778-1.
  46. ↑ Séguin, Annie (2014). "Body size as a predictor of species loss effect on ecosystem functioning". Scientific Reports. 4 – via Nature.


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