Chapter 10
Pathogens of Vertebrate Animals
as Invasive Species: Insights from
South Africa
Lesley van Helden , Paul D. van Helden , and Christina Meiring
Abstract The study of disease organisms as invasive alien species has not received
a great deal of attention in the field of invasion science. Introduced pathogens can
have profound effects on living organisms, the ecosystems that they inhabit, and the
economies that the ecosystems support. In this chapter, we use case studies of
introduced diseases of domestic and wild animals (canine rabies, bovine tuberculosis, and rinderpest) and humans (smallpox, measles and human immunodeficiency
virus, HIV) to illustrate the kinds of effects that these pathogens can have. The most
dramatic impact to date was that of rinderpest, which caused the death of millions of
cattle, and practically annihilated certain forms of wildlife from large parts of
southern Africa. This in turn impacted severely on the region’s economy, and
resulted in large-scale changes to the structure and dynamics of ecosystems. Rinderpest has been eradicated globally, but both canine rabies and bovine tuberculosis
remain, and ongoing vigilance and management will be required to contain them. Of
the human diseases, smallpox has also been eradicated globally, but the effect of the
disease, introduced by European colonists, was devastating. In the early 1700s, a
large proportion (up to 90% in some communities) of the indigenous Khoekhoe
people died, destroying their culture and way of life, and leaving the few survivors to
be recruited as farm labourers. HIV, first detected in South Africa in 1982 has also
had substantial impacts and antiretroviral treatment alone currently costs the government ZAR 66.4 billion annually. We also include West Nile Virus and African
Swine Fever as examples of diseases that originated in Africa, and that may yet
become globally destructive. We predict that new diseases will emerge as humans
continue to expand their range into wild areas, and as trade volumes increase.
L. van Helden
Department of Agriculture, Western Cape Veterinary Services, Cape Town, South Africa
P. D. van Helden (*) · C. Meiring
DSI-NRF Centre of Excellence for Biomedical Tuberculosis Research, Faculty of Medicine and
Health Sciences, Stellenbosch University, Stellenbosch, South Africa
South African Medical Research Council Centre for Tuberculosis Research, Faculty of
Medicine and Health Sciences, Stellenbosch University, Stellenbosch, South Africa
e-mail: pvh@sun.ac.za
© The Author(s) 2020
B. W. van Wilgen et al. (eds.), Biological Invasions in South Africa, Invading
Nature - Springer Series in Invasion Ecology 14,
https://doi.org/10.1007/978-3-030-32394-3_10
249
Pathogens of Vertebrate Animals
as Invasive Species: Insights from
South Africa
Lesley van Helden , Paul D. van Helden , and Christina Meiring
Abstract The study of disease organisms as invasive alien species has not received
a great deal of attention in the field of invasion science. Introduced pathogens can
have profound effects on living organisms, the ecosystems that they inhabit, and the
economies that the ecosystems support. In this chapter, we use case studies of
introduced diseases of domestic and wild animals (canine rabies, bovine tuberculosis, and rinderpest) and humans (smallpox, measles and human immunodeficiency
virus, HIV) to illustrate the kinds of effects that these pathogens can have. The most
dramatic impact to date was that of rinderpest, which caused the death of millions of
cattle, and practically annihilated certain forms of wildlife from large parts of
southern Africa. This in turn impacted severely on the region’s economy, and
resulted in large-scale changes to the structure and dynamics of ecosystems. Rinderpest has been eradicated globally, but both canine rabies and bovine tuberculosis
remain, and ongoing vigilance and management will be required to contain them. Of
the human diseases, smallpox has also been eradicated globally, but the effect of the
disease, introduced by European colonists, was devastating. In the early 1700s, a
large proportion (up to 90% in some communities) of the indigenous Khoekhoe
people died, destroying their culture and way of life, and leaving the few survivors to
be recruited as farm labourers. HIV, first detected in South Africa in 1982 has also
had substantial impacts and antiretroviral treatment alone currently costs the government ZAR 66.4 billion annually. We also include West Nile Virus and African
Swine Fever as examples of diseases that originated in Africa, and that may yet
become globally destructive. We predict that new diseases will emerge as humans
continue to expand their range into wild areas, and as trade volumes increase.
L. van Helden
Department of Agriculture, Western Cape Veterinary Services, Cape Town, South Africa
P. D. van Helden (*) · C. Meiring
DSI-NRF Centre of Excellence for Biomedical Tuberculosis Research, Faculty of Medicine and
Health Sciences, Stellenbosch University, Stellenbosch, South Africa
South African Medical Research Council Centre for Tuberculosis Research, Faculty of
Medicine and Health Sciences, Stellenbosch University, Stellenbosch, South Africa
e-mail: pvh@sun.ac.za
© The Author(s) 2020
B. W. van Wilgen et al. (eds.), Biological Invasions in South Africa, Invading
Nature - Springer Series in Invasion Ecology 14,
https://doi.org/10.1007/978-3-030-32394-3_10
249