as having Massive environmental impacts through damage to vegetation while
feeding, and moderate socio-economic impacts (Hagen and Kumschick 2018).
They are listed as invasive species under the Regulations when they occur on
offshore islands.
5.3.11 Rodentia
Globally, invasive rodents threaten agricultural food production and act as reservoirs
for disease (Stenseth et al. 2003). One of the most important impacts of rats in
South African urban areas are those of zoonotic diseases (see van Helden et al. 2020,
Chap. 10), including leptospirosis, plague (caused by the bacillus Yersinia pestis
transmitted from rats via fleas to humans), and toxoplasmosis in humans (Taylor
et al. 2008). They also carry several co-invasive parasites (Julius et al. 2018a, b).
Bartonella and Helicobacter have been found in all three species of Rattus in
South Africa. For example, a survey of rats in formal and informal housing in
Durban found that the rodents carried toxoplasmosis and leptospirosis, but not
plague (Taylor et al. 2008). It has also been suggested that, in South African urban
areas, zoonotic disease prevalence may increase due to the compromised immune
systems of HIV/AIDS patients (van Rensburg et al. 2011).
5.3.11.1 Mus musculus (House mice)
House mice were likely introduced to southern Africa through early shipping. There
are no early records that specifically relate to this species, and its distribution is now
cosmopolitan in South Africa, and sub-saharan Africa (Monadjem et al. 2015). Most
studies on this species relate to South Africa’s sub-Antarctic islands, where impacts
are massive, and these are covered elsewhere (Greve et al. 2020, Chap. 8). On the
mainland, its impact appears to be mostly socio-economic (moderate) (Hagen and
Kumschick 2018), including spoiling of stored foods. Most occurrence records are
associated with building and are apparently scant elsewhere (e.g. Avery 1992). It
should not be forgotten that the introduction of mice and rats has been followed in
many instances by the introduction of cats to control them, and their impacts may
therefore be related. House mice are listed as Category 1b in terms of the Regulations
when they occur on offshore islands.
5.3.11.2 Rattus rattus (House Rats)
House rats were likely introduced to South Africa in pre-historical times
(700–800 AD; Deacon 1986). However, genetic lineages collected in Cape Town
suggest that, unlike animals collected on South Africa’s south coast that are related
5 Terrestrial Vertebrate Invasions in South Africa
127
feeding, and moderate socio-economic impacts (Hagen and Kumschick 2018).
They are listed as invasive species under the Regulations when they occur on
offshore islands.
5.3.11 Rodentia
Globally, invasive rodents threaten agricultural food production and act as reservoirs
for disease (Stenseth et al. 2003). One of the most important impacts of rats in
South African urban areas are those of zoonotic diseases (see van Helden et al. 2020,
Chap. 10), including leptospirosis, plague (caused by the bacillus Yersinia pestis
transmitted from rats via fleas to humans), and toxoplasmosis in humans (Taylor
et al. 2008). They also carry several co-invasive parasites (Julius et al. 2018a, b).
Bartonella and Helicobacter have been found in all three species of Rattus in
South Africa. For example, a survey of rats in formal and informal housing in
Durban found that the rodents carried toxoplasmosis and leptospirosis, but not
plague (Taylor et al. 2008). It has also been suggested that, in South African urban
areas, zoonotic disease prevalence may increase due to the compromised immune
systems of HIV/AIDS patients (van Rensburg et al. 2011).
5.3.11.1 Mus musculus (House mice)
House mice were likely introduced to southern Africa through early shipping. There
are no early records that specifically relate to this species, and its distribution is now
cosmopolitan in South Africa, and sub-saharan Africa (Monadjem et al. 2015). Most
studies on this species relate to South Africa’s sub-Antarctic islands, where impacts
are massive, and these are covered elsewhere (Greve et al. 2020, Chap. 8). On the
mainland, its impact appears to be mostly socio-economic (moderate) (Hagen and
Kumschick 2018), including spoiling of stored foods. Most occurrence records are
associated with building and are apparently scant elsewhere (e.g. Avery 1992). It
should not be forgotten that the introduction of mice and rats has been followed in
many instances by the introduction of cats to control them, and their impacts may
therefore be related. House mice are listed as Category 1b in terms of the Regulations
when they occur on offshore islands.
5.3.11.2 Rattus rattus (House Rats)
House rats were likely introduced to South Africa in pre-historical times
(700–800 AD; Deacon 1986). However, genetic lineages collected in Cape Town
suggest that, unlike animals collected on South Africa’s south coast that are related
5 Terrestrial Vertebrate Invasions in South Africa
127