278
organization is widely conserved in three of the up to four acanthocephalan taxa
with the traditional rank of a class, i.e. Palaeacanthocephala, Eoacanthocephala, and
Polyacanthocephala. The same is true for Gigantorhynchida, Moniliformida, and
Oligacanthorhynchida, which are ranked as orders within the fourth acanthocephalan class, Archiacanthocephala. In contrast, archiacanthocephalans belonging to the
order Apororhynchida have an inflated proboscis and a comparably small metasoma
(e.g., Petrochenko 1956, 1958; Herlyn 2017).
8.2 Acanthocephalans in Hominoids and Potential
Reservoirs for Human Infections
The probably first case report of an infection of a human with an acanthocephalan
was reported from Bohemia in the middle of the nineteenth century (Lambl 1859).
The single female of Macracanthorhynchus hirudinaceus was excised from the
intestine of a 9-year-old boy who had died of leukemia. How exactly the boy
acquired the worm has to remain unanswered but one possible route of infection
would be the intake of an infected grub of a scarabeid beetle (Coleoptera,
Scarabeidae) (Pavlović et al. 2010). Indeed, people can generally acquire infections
with acanthocephalans when they eat raw or insufficiently cooked intermediate
hosts (e.g., Grassi and Calandruccio 1888; Zhong et al. 1983; Sahar et al. 2006;
Mehlhorn 2016). Obviously, this happens quite regularly as demonstrated by
Mathison et al. (2016). The study lists cases of infections with M. hirudinaceus and
Macracanthorhynchus ingens from 11 countries in Asia, Australia, Europe, North
America, and South America, and infections with Moniliformis moniliformis from
16 countries in the same continents plus Africa. In addition, humans may get
infected when eating raw crayfish and fish, as discussed for acanthocephalans of the
genera Bolbosoma and Corynosoma (e.g., Kaito et al. 2019; Sasaki et al. 2019).
The risk of human infections should be higher when mandibulates such as scarabeid grubs are infected at increased rate, and this should also be more likely to be
the case when reservoir hosts live in vicinity of people. These can be omnivorous
farm animals kept in the open. Outdoor management is still common in many parts
of the world, and previously has been widespread in countries where it is now the
exception. Thus, in the nineteenth century a veterinarian reported high morbidity in
a herd of grazing piglets (Sus scrofa domestica, Suinae) in Hungary as a result of
infection with M. hirudinaceus (Kocourek 1877). According to a note by the editorial office scarabeid beetles of the genus Melolontha represented the probable source
of infection (see also Pavlović et al. 2010). Another report from the second half of
the nineteenth century states that 40% of the swine slaughtered in Catania (Italy)
were infected with M. hirudinaceus (Grassi and Calandruccio 1888). However,
archiacanthocephalans have also found ways to exploit farm animals until more
recently. Thus, M. hirudinaceus specimens could be collected for a study published
in 2000 in the abattoir of La Paz (Bolivia), from butchered swine that were kept
under outdoor management before. Yet macracanthorhynchiasis is not restricted to
H. Herlyn
organization is widely conserved in three of the up to four acanthocephalan taxa
with the traditional rank of a class, i.e. Palaeacanthocephala, Eoacanthocephala, and
Polyacanthocephala. The same is true for Gigantorhynchida, Moniliformida, and
Oligacanthorhynchida, which are ranked as orders within the fourth acanthocephalan class, Archiacanthocephala. In contrast, archiacanthocephalans belonging to the
order Apororhynchida have an inflated proboscis and a comparably small metasoma
(e.g., Petrochenko 1956, 1958; Herlyn 2017).
8.2 Acanthocephalans in Hominoids and Potential
Reservoirs for Human Infections
The probably first case report of an infection of a human with an acanthocephalan
was reported from Bohemia in the middle of the nineteenth century (Lambl 1859).
The single female of Macracanthorhynchus hirudinaceus was excised from the
intestine of a 9-year-old boy who had died of leukemia. How exactly the boy
acquired the worm has to remain unanswered but one possible route of infection
would be the intake of an infected grub of a scarabeid beetle (Coleoptera,
Scarabeidae) (Pavlović et al. 2010). Indeed, people can generally acquire infections
with acanthocephalans when they eat raw or insufficiently cooked intermediate
hosts (e.g., Grassi and Calandruccio 1888; Zhong et al. 1983; Sahar et al. 2006;
Mehlhorn 2016). Obviously, this happens quite regularly as demonstrated by
Mathison et al. (2016). The study lists cases of infections with M. hirudinaceus and
Macracanthorhynchus ingens from 11 countries in Asia, Australia, Europe, North
America, and South America, and infections with Moniliformis moniliformis from
16 countries in the same continents plus Africa. In addition, humans may get
infected when eating raw crayfish and fish, as discussed for acanthocephalans of the
genera Bolbosoma and Corynosoma (e.g., Kaito et al. 2019; Sasaki et al. 2019).
The risk of human infections should be higher when mandibulates such as scarabeid grubs are infected at increased rate, and this should also be more likely to be
the case when reservoir hosts live in vicinity of people. These can be omnivorous
farm animals kept in the open. Outdoor management is still common in many parts
of the world, and previously has been widespread in countries where it is now the
exception. Thus, in the nineteenth century a veterinarian reported high morbidity in
a herd of grazing piglets (Sus scrofa domestica, Suinae) in Hungary as a result of
infection with M. hirudinaceus (Kocourek 1877). According to a note by the editorial office scarabeid beetles of the genus Melolontha represented the probable source
of infection (see also Pavlović et al. 2010). Another report from the second half of
the nineteenth century states that 40% of the swine slaughtered in Catania (Italy)
were infected with M. hirudinaceus (Grassi and Calandruccio 1888). However,
archiacanthocephalans have also found ways to exploit farm animals until more
recently. Thus, M. hirudinaceus specimens could be collected for a study published
in 2000 in the abattoir of La Paz (Bolivia), from butchered swine that were kept
under outdoor management before. Yet macracanthorhynchiasis is not restricted to
H. Herlyn