causing high mortalities as far as the Transkei and Transgariep. Land was vacated,
allowing settlers to occupy more of the country, while political and social structures
disintegrated in the face of deaths of community leaders, large proportions of the
population and almost entire generations of children. The scattered survivors were
recruited as farm labourers. The use of smallpox vaccine at the beginning of the
nineteenth century put a stop to outbreaks of the disease in South Africa, but it was
too late for the indigenous way of life of the Khoekhoe, whose society had collapsed
and many had now transitioned into being permanent farm labourers (Phillips 2012).
10.3.2 Measles
The measles and rinderpest viruses share a common ancestor, but whereas rinderpest
evolved to specialise in ruminants, measles evolved to specialise in humans. Thus
we consider that measles most likely evolved where humans and cattle were in close
contact, and the first good records of measles outbreaks date from the eleventh or
twelfth centuries. It is likely that at this time, the virus could switch hosts (Furuse
et al. 2010). During the Middle Ages, measles became established as an endemic
disease throughout the Middle East, North Africa and the Old World.
Spanish explorers took measles and smallpox to the New World, where they
caused devastating epidemics in the early sixteenth century. Smallpox was evident in
Mexico in 1515 and among the Incas by 1524. Measles probably appeared later, in
1529 (Retief and Cilliers 2010). Indigenous people in South Africa were similarly
dramatically affected by measles. It is not possible to estimate what proportion of the
population died from measles as opposed to other causes, but whole clans would
disappear. The concentration camps established during the South African War
(1898–1902), where large numbers of people were clustered together under poor
living conditions, also gave impetus to measles-driven mortality and spread, particularly since most individuals were malnourished and stressed and exposed to many
bacterial pathogens which may have rendered them hyper-susceptible (Shanks et al.
2014). Similar to rinderpest, the measles virus has spread globally and is tractable
to vaccination. Unlike rinderpest, it is not yet eradicated, and the World Health
Organization estimates that currently 400 children die per day from measles, and
rather unexpectedly there is currently a growing epidemic, even in Europe (World
Health Organization 2016). The development and worldwide deployment of an
effective vaccine quickly led to a decline in measles cases (Greenwood 2014).
Despite encouragement and provision of free wide-scale vaccination of newborns
using a highly effective Measles, Mumps, and Rubella vaccine, not every
South African infant, like those in many countries, is vaccinated (Ntshoe et al.
2013). There are various reasons for this, including poor access to health care for
some individuals, and refusal to vaccinate in the case of others (Kagoné et al. 2017).
This means that South Africa, like many other countries, has a population of
susceptible individuals to continue hosting the disease, so we have a small number
of active cases every year, with occasional outbreaks. Under these conditions, local
and global eradication will be impossible. Essentially, the key difference between
10 Pathogens of Vertebrate Animals as Invasive Species: Insights from South Africa
263
allowing settlers to occupy more of the country, while political and social structures
disintegrated in the face of deaths of community leaders, large proportions of the
population and almost entire generations of children. The scattered survivors were
recruited as farm labourers. The use of smallpox vaccine at the beginning of the
nineteenth century put a stop to outbreaks of the disease in South Africa, but it was
too late for the indigenous way of life of the Khoekhoe, whose society had collapsed
and many had now transitioned into being permanent farm labourers (Phillips 2012).
10.3.2 Measles
The measles and rinderpest viruses share a common ancestor, but whereas rinderpest
evolved to specialise in ruminants, measles evolved to specialise in humans. Thus
we consider that measles most likely evolved where humans and cattle were in close
contact, and the first good records of measles outbreaks date from the eleventh or
twelfth centuries. It is likely that at this time, the virus could switch hosts (Furuse
et al. 2010). During the Middle Ages, measles became established as an endemic
disease throughout the Middle East, North Africa and the Old World.
Spanish explorers took measles and smallpox to the New World, where they
caused devastating epidemics in the early sixteenth century. Smallpox was evident in
Mexico in 1515 and among the Incas by 1524. Measles probably appeared later, in
1529 (Retief and Cilliers 2010). Indigenous people in South Africa were similarly
dramatically affected by measles. It is not possible to estimate what proportion of the
population died from measles as opposed to other causes, but whole clans would
disappear. The concentration camps established during the South African War
(1898–1902), where large numbers of people were clustered together under poor
living conditions, also gave impetus to measles-driven mortality and spread, particularly since most individuals were malnourished and stressed and exposed to many
bacterial pathogens which may have rendered them hyper-susceptible (Shanks et al.
2014). Similar to rinderpest, the measles virus has spread globally and is tractable
to vaccination. Unlike rinderpest, it is not yet eradicated, and the World Health
Organization estimates that currently 400 children die per day from measles, and
rather unexpectedly there is currently a growing epidemic, even in Europe (World
Health Organization 2016). The development and worldwide deployment of an
effective vaccine quickly led to a decline in measles cases (Greenwood 2014).
Despite encouragement and provision of free wide-scale vaccination of newborns
using a highly effective Measles, Mumps, and Rubella vaccine, not every
South African infant, like those in many countries, is vaccinated (Ntshoe et al.
2013). There are various reasons for this, including poor access to health care for
some individuals, and refusal to vaccinate in the case of others (Kagoné et al. 2017).
This means that South Africa, like many other countries, has a population of
susceptible individuals to continue hosting the disease, so we have a small number
of active cases every year, with occasional outbreaks. Under these conditions, local
and global eradication will be impossible. Essentially, the key difference between
10 Pathogens of Vertebrate Animals as Invasive Species: Insights from South Africa
263