Prosthogonimus macrorchis

Geographic Range

Prosthogonimus macrorchis is an avian parasite found in regions of the United States and Canada near the Great Lakes. Prosthogonimus macrorchis is known for causing a reduction or termination in egg production in domestic fowl. (Brooks, et al., 1993; Huffman, 2009; Olsen, 1967)


Prosthogonimus macrorchis inhabits areas surrounding the Great Lakes, mainly aquatic environments. Eggs are expelled from the ultimate avian host through the anus and into freshwater at the surface of the water column. The first intermediate host, typically a snail, consumes eggs that sink to the bottom of the water column. Adults live in the oviducts of avian species such as ducks, chickens, sparrows, and crows that become infected by consuming infected insects. The oviduct environment is most suitable during reproduction. (Burt, 1970; Huffman, 2009; Olsen, 1967)

  • Aquatic Biomes
  • lakes and ponds

Physical Description

The adult body of Prosthogonimus macrorchis is flat and transparent with spines on the cuticle, a body plan typical of trematodes. An adult is about 8 mm long and 5 mm wide, and the posterior end appears broader than the anterior end. The ventral sucker is about 2 mm away from the anterior end of the body, and another smaller sucker is at the anterior end. The pharynx lies beneath the anterior sucker, and is connected to the esophagus, which leads into the intestine. The intestine consists of two lobes that are positioned laterally on each side of the body. The uterus occupies about half of the body at the posterior end. Two large testes lie about halfway between the ventral sucker and the posterior end of the body. The ovary contains multiple lobes and is between the ventral sucker and the testes. A genital pore is adjacent to the anterior sucker. Vitelline ducts appear on the left and right sides of the body, connected to the ovary by the vitelline gland. (Huffman, 2009; Olsen, 1967; Permin and Hansen, 1998)

  • Range length
    7 to 9 mm
    0.28 to 0.35 in


Prosthogonimus macrorchis embryos, known as miracidia larvae, are released into the water column by the definitive host. Hatching occurs in the first intermediate host, snails. Miracidia larvae travel through the digestive tract of the first intermediate host and burrow through the intestinal wall. Larvae then transform into sporocysts, at which time they lose cilia. Daughter sporocysts have been found in snail digestive glands, but mother sporocysts, which use asexual reproduction to produce more daughter sporocysts, have not been found. Cercariae are released from the daughter sporocyst. The snail intermediate host will release tailed cercariae into the water through the feces. Currents made by respiration of a dragon fly naiad cause cercariae to enter its rectal chamber, and it becomes the second intermediate host. The cercariae then become encysted metacercariae. Transmission to the ultimate host occurs when fowl consume infected dragonflies. Metacercariae are released into the digestive tract as the infected insects are digested. Conditions in the digestive tract of the ultimate host allow for the metacercariae to become excysted. As metacercariae mature into the adult phase, they migrate to the oviduct of the ultimate host, where reproduction occurs. (Huffman, 2009; Olsen, 1967)


Individuals of Prosthogonimus macrorchis are monoecious and can self fertilize. (Huffman, 2009; Olsen, 1967)

Prosthogonimus macrorchis tends to reproduce more in the spring and summer. Reproduction is not common in the winter, as few fowl species are available, and reproduction is not possible without the ultimate host. Also, if bodies of water are frozen, snails that inhabit benthic regions cannot obtain eggs. Oviducts of the ultimate hosts provide a suitable environment for adult P. macrorchis during the hosts’ breeding season, and facilitate P. macrorchis reproduction. Eggs are typically laid in the spring, and transfer to dragonfly naiads typically occurs during the summer. Asexual reproduction also occurs during the sporocyst stage of development.

Key reproductive features monoecious, digenetic Age at sexual or reproductive maturity 80 to 90 days (Crompton and Joyner, 1980; Olsen, 1967)

  • Breeding season
    This species mainly reproduces in the spring.
  • Range age at sexual or reproductive maturity (female or asexual)
    80 to 90 days
  • Range age at sexual or reproductive maturity (male)
    80 to 90 days

Beyond the limited provisioning of eggs, there is no parental investment.

  • Parental Investment
  • no parental involvement
  • pre-hatching/birth
    • provisioning
      • female


The total lifespan of Prosthogonimus macrorchis is about 80 to 115 days in chickens and about 125 days in ducks. The metacercariae stage is reached after the first 70 days of this period. Metacercariae become adults after about one week in the ultimate host in chickens and three weeks in ducks. (Olsen, 1967)

  • Average lifespan
    Status: wild
    115 days


Prosthogonimus macrorchis, like other trematode parasites, has multiple hosts. A snail in the genus Amnicola is the first intermediate host, and it becomes infected by eating feces from a bird that contains P. macrorchis eggs. Inside the snail, daughter sporocysts produce a large number of cercariae that are released into the water to search for their next intermediate host, a dragonfly naiad. They enter a dragonfly through the posterior end of the naiad and are sucked into the dragonfly through the anus. Within the dragonfly, the parasites break through a thin cuticle layer with their stylet. In the muscles of the naiad the parasites encyst as a metacercariae, which are not free moving. When birds consume the dragonfly containing P. macrorchis, they too, become infected. The parasite excysts in the infected bird’s small intestine and then travels through the bird until it is excreted, restarting the process. (Macy, 1934; Sullivan, 2007)

Communication and Perception

Prosthogonimus macrorchis adults perceive tactile stimuli using tangoreceptors. Chemoreceptors and light receptors are needed less in the adult stage than in the larval stages, because the larval stages need them to locate their hosts. Chematotactic cues, used used in the larval stage, are sensed by their chemoreceptors to find their snail host. There are no studies on other communication of P. macrorchis. (Smyth and Halton, 1983)

Food Habits

Both the intermediate and definitive hosts of Prosthogonimus macrorchis give the parasite its ability to live, because it feeds off of its hosts’ body fluids. (Macy, 1934)

  • Animal Foods
  • body fluids


There are no known direct predators of Prosthogonimus macrorchis, although it is indirectly consumed by host organisms. (Macy, 1934; Sullivan, 2007)

Ecosystem Roles

Prosthogonimus macrorchis is an endoparasite, found intercellularly within an organism. It can be found in the Great Lakes area, inside Amnicola snails and dragonflies, its two intermediate hosts. The definitive hosts of P. macrorchis are chickens (Galliformes), ducks (Anseriformes), and wild birds (Passeriformes). (Macy, 1934)

Species Used as Host

Economic Importance for Humans: Positive

There are no known positive effects of Prosthogonimus macrorchis on humans.

Economic Importance for Humans: Negative

When the intermediate hosts come in contact with Prosthogonimus macrorchis, they become infected, but it is the definitive host that shows signs of real damage. The parasite can be found within the bird’s bursa of Fabricius, the oviduct, or the hindgut. There, Prosthogonimus macrorchis causes damage to the bird’s organs or even rupture the oviduct. This results in chickens laying eggs without a shell, or even the prevention of their eggs being laid. (Macy, 1934)

Conservation Status

This species does not have any conservation status.


Hanna Berman (author), The College of New Jersey, Alanna Spellman (author), The College of New Jersey, Keith Pecor (editor), The College of New Jersey, Renee Mulcrone (editor), Special Projects.



living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.

World Map


reproduction that is not sexual; that is, reproduction that does not include recombining the genotypes of two parents

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.


an animal that mainly eats meat

causes or carries domestic animal disease

either directly causes, or indirectly transmits, a disease to a domestic animal


uses smells or other chemicals to communicate


animals which must use heat acquired from the environment and behavioral adaptations to regulate body temperature


mainly lives in water that is not salty.


having a body temperature that fluctuates with that of the immediate environment; having no mechanism or a poorly developed mechanism for regulating internal body temperature.


A large change in the shape or structure of an animal that happens as the animal grows. In insects, "incomplete metamorphosis" is when young animals are similar to adults and change gradually into the adult form, and "complete metamorphosis" is when there is a profound change between larval and adult forms. Butterflies have complete metamorphosis, grasshoppers have incomplete metamorphosis.


having the capacity to move from one place to another.


specialized for swimming


an organism that obtains nutrients from other organisms in a harmful way that doesn't cause immediate death

seasonal breeding

breeding is confined to a particular season


non-motile; permanently attached at the base.

Attached to substratum and moving little or not at all. Synapomorphy of the Anthozoa


reproduction that includes combining the genetic contribution of two individuals, a male and a female


uses touch to communicate


that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).


Brooks, D., E. Hoberg, A. Houtman. 1993. Some platyhelminths inhabiting white-throated sparrows, Zonotrichia albicollis (Aves: Emberizidae: Emberizinae), from Algonquin Park, Ontario, Canada. Journal of Parasitology, 79: 610-612.

Burt, D. 1970. Platyhelminthes and parasitism. London: English Universities Press.

Crompton, D., S. Joyner. 1980. Parasitic worms. New York: Wykeham Publications.

Huffman, J. 2009. Trematodes. Pp. 225-245 in C Atkinson, N Thomas, B Hunter, eds. Parasitic diseases of wild birds. Iowa: Wiley-Blackwell.

John T., S. 2007. A color atlas of parasitology. San Francisco, CA: University of San Francisco.

Macy, R. 1934. Studies on the taxonomy, morphology, and biology of Prosthogonimus macrochis Macy, a common oviduct fluke of domestic fowls in North America. Minnesota: University Farm.

Olsen, O. 1967. Animal parasites: Their biology and life cycles. Colorado: Burgess Publishing.

Permin, A., J. Hansen. 1998. The epidemiology, diagnosis, and control of poultry parasites. Rome: Food and Agriculture Organization of the United Nations.

Smyth, J., D. Halton. 1983. The physiology of trematodes, 2nd edition. Cambridge: Cambridge University Press.

Sullivan, J. 2007. A color atlas of parasitology. San Francisco, California: Parasitology.