279
domestic swine as illustrated by an infected herd of white-lipped peccaries (Tayassu
pecari, Suinae) kept in pasture in Brazil (de Almeida et al. 2006). Last but not least,
archiacanthocephalans also occur in farm animals other than mammals. For example, chicken (Gallus gallus domesticus) can be parasitized by Mediorhynchus gallinorum, as has been observed in Indonesia (Amin et al. 2013). Accordingly, eggs of
Archiacanthocephala might also be contained in old manure of human farm animals, although the preservation of pig and chicken manure might be a rarity per se.
Infections of farm animals and humans probably take place again and again
somewhere in the world. However, it is also clear that the ongoing industrialization
of animal production, in particular the separation of livestock from intermediate
hosts, impairs the establishment of acanthocephalan life cycles with humans
as hosts (compare Dunagan and Miller 1980). On the other hand, acanthocephalans
do not depend on farm animals for getting into the vicinity of people since other
mammals with a more or less close connection to humans can also be infected. In
Tunisia, for instance, the occurence of M. hirudinaceus was shown for stray dogs
(Canis familiaris, Carnivora) (Lahmar et al. 2017). This illustrates that the human
companion can act as a reservoir for infections of people. But also mice and rats
(Mus or Rattus, both Rodentia), raccoons (Procyon lotor, Carnivora), wild boar etc.
can carry acanthocephalans, and due to their occurrence in or near settlements can
be a reservoir for infections of humans and farm animals (Grassi and Calandruccio
1888; Dingley and Beaver 1985; Gassó et al. 2016; Kogi et al. 2016).
Raw animal food, including insects, should have contributed more to human
nutrition in prehistoric times than today (Reinhard 1990; Gonçalves et al. 2003
Reinhard 2017). The mandibulates might have been collected in the surrounding
landscape but also in human accomodations such as caves. In fact, the chance of
ingesting an acanthella or cystacanth is not to be underestimated when eating a protein source like an insect in a raw or insufficiently cooked state. For example, the
archiacanthocephalan Moniliformis dubius was found in up to 35% of the cockroaches (Periplaneta americana, Blattodea) collected from the lecture halls of a
Nigerian university (Kogi et al. 2016). Thereby, the intensity of infection can reach
considerable levels of more than 100 juvenile stages per individual intermediate
host, as reported for M. moniliformis in beetles of the species Blaps mucronata
(Coleoptera, Tenebrionidae) (Grassi and Calandruccio 1888). Accordingly, the
uptake of a single intermediate host can be sufficient to enable acanthocephalan
reproduction. In fact, Grassi and Calandruccio (1888) demonstrated that acanthocephalan eggs are contained in human stool upon infection with several cystacanths.
Not least, eggs in human coprolites demonstrate that our species can serve as definitive host for archiacanthocephalans (see Table 8.1).
The anatomically modern Homo sapiens is not the only species within hominoids (Primates, Hominoidea) that can be parasitized by acanthocephalans.
Also small apes (Hylobatidae), orangutans (Pongo), gorillas (Gorilla) and chimpanzees (Pan) sporadically take in insects, which can carry developmental stages of
archiacanthocephalans (e.g., Van Thiel and Bruss 1945; Myers and Kuntz 1972).
This phenomenon is actually not restricted to hominoids and rather affects other
primates as well (Richart and Benirschke 1963; Solórzano-García and Pérez-Ponce
8 Thorny-Headed Worms (Acanthocephala): Jaw-Less Members of Jaw-Bearing…
domestic swine as illustrated by an infected herd of white-lipped peccaries (Tayassu
pecari, Suinae) kept in pasture in Brazil (de Almeida et al. 2006). Last but not least,
archiacanthocephalans also occur in farm animals other than mammals. For example, chicken (Gallus gallus domesticus) can be parasitized by Mediorhynchus gallinorum, as has been observed in Indonesia (Amin et al. 2013). Accordingly, eggs of
Archiacanthocephala might also be contained in old manure of human farm animals, although the preservation of pig and chicken manure might be a rarity per se.
Infections of farm animals and humans probably take place again and again
somewhere in the world. However, it is also clear that the ongoing industrialization
of animal production, in particular the separation of livestock from intermediate
hosts, impairs the establishment of acanthocephalan life cycles with humans
as hosts (compare Dunagan and Miller 1980). On the other hand, acanthocephalans
do not depend on farm animals for getting into the vicinity of people since other
mammals with a more or less close connection to humans can also be infected. In
Tunisia, for instance, the occurence of M. hirudinaceus was shown for stray dogs
(Canis familiaris, Carnivora) (Lahmar et al. 2017). This illustrates that the human
companion can act as a reservoir for infections of people. But also mice and rats
(Mus or Rattus, both Rodentia), raccoons (Procyon lotor, Carnivora), wild boar etc.
can carry acanthocephalans, and due to their occurrence in or near settlements can
be a reservoir for infections of humans and farm animals (Grassi and Calandruccio
1888; Dingley and Beaver 1985; Gassó et al. 2016; Kogi et al. 2016).
Raw animal food, including insects, should have contributed more to human
nutrition in prehistoric times than today (Reinhard 1990; Gonçalves et al. 2003
Reinhard 2017). The mandibulates might have been collected in the surrounding
landscape but also in human accomodations such as caves. In fact, the chance of
ingesting an acanthella or cystacanth is not to be underestimated when eating a protein source like an insect in a raw or insufficiently cooked state. For example, the
archiacanthocephalan Moniliformis dubius was found in up to 35% of the cockroaches (Periplaneta americana, Blattodea) collected from the lecture halls of a
Nigerian university (Kogi et al. 2016). Thereby, the intensity of infection can reach
considerable levels of more than 100 juvenile stages per individual intermediate
host, as reported for M. moniliformis in beetles of the species Blaps mucronata
(Coleoptera, Tenebrionidae) (Grassi and Calandruccio 1888). Accordingly, the
uptake of a single intermediate host can be sufficient to enable acanthocephalan
reproduction. In fact, Grassi and Calandruccio (1888) demonstrated that acanthocephalan eggs are contained in human stool upon infection with several cystacanths.
Not least, eggs in human coprolites demonstrate that our species can serve as definitive host for archiacanthocephalans (see Table 8.1).
The anatomically modern Homo sapiens is not the only species within hominoids (Primates, Hominoidea) that can be parasitized by acanthocephalans.
Also small apes (Hylobatidae), orangutans (Pongo), gorillas (Gorilla) and chimpanzees (Pan) sporadically take in insects, which can carry developmental stages of
archiacanthocephalans (e.g., Van Thiel and Bruss 1945; Myers and Kuntz 1972).
This phenomenon is actually not restricted to hominoids and rather affects other
primates as well (Richart and Benirschke 1963; Solórzano-García and Pérez-Ponce
8 Thorny-Headed Worms (Acanthocephala): Jaw-Less Members of Jaw-Bearing…