Paramphistomum cervi

Geographic Range

The livestock rumen fluke, Paramphistomum cervi, is found in mostly tropical and subtropical regions, including Australia, Asia, Africa, Eastern Europe, and Russia. More specifically, specimens have been reported in Europe from Bulgaria, Italy, France, and Poland and also in Asia from Thailand, India, and China. (Boray, 1959)


Adult Paramphistomum cervi live in the rumens of ruminants (goats, sheep, cattle, and buffaloes) until the adults lay eggs which are passed through the animals in their feces. The optimal water temperature for egg development is 27 degrees C. Miracidia live in the water where the eggs they hatched from were deposited, and the sporocysts, rediae, and cercariae all live inside the intermediate snail host. The cercariae eventually emerge from the snail to encyst on aquatic herbage in order to be ingested by definite ruminant hosts. (Olsen, 1986; Rangel-Ruiz, et al., 2003)

  • Aquatic Biomes
  • lakes and ponds
  • temporary pools

Physical Description

Paramphistomum cervi are conical and pink with the ventral side being more concave than the convex dorsal side. An anterior oral sucker and posterior larger ventral sucker are present, as is common for many trematodes. The anterior end is tapered in comparison to the wider posterior end. Testes are slightly lobed and are located anterior to the ovary. Both ovary and testes are in the posterior half of the fluke. (Olsen, 1986)

  • Range length
    5 to 12 mm
    0.20 to 0.47 in


Eggs are released in water and hatch after developing into a miracidia. The non-feeding miracidia often swim through water searching for a suitable snail host, either until they reach the host or die. When sensing the soft outer layer of a snail, they attach and burrow into the tissue. The miracidia transform to mature sporocysts in about 11 days, and release rediae. Rediae mature with in 10 days with 15-30 cercariae. For mature cercariae to emerge from their intermediate hosts at an optimal time (during the day), they have two eyespots capable of sensing light. After emergence, they encyst on plants to reach their next host, a ruminant. Excystment of metacercariae occurs when they sense the changed physicochemical conditions (such as temperature, substance concentration, and pH) inside the ruminant host, and adult flukes utilize topological features in the intestines of ruminants in order to guide their migration. The time from infection to egg release after the adult's mature is about 60 to 120 days. (Olsen, 1986; Sukhdeo and Sukhdeo, 2004)


The mating systems are not complex, as adult Paramphistomum cervi are monoecious (having both male and female organs), and self-fertilize. (Olsen, 1986)

Adult rumen flukes are monoecious, fertilizing their own eggs and keeping them inside the uterus. Egg release is synchronized with the emergence from hibernation of their intermediate snail hosts. The flukes reach sexual maturity in the rumens of ruminants and release eggs in the intestine and which are expelled along with feces. The time from egg hatching to a mature adult releasing eggs is about 95 days. (Olsen, 1986)

  • Range age at sexual or reproductive maturity (female or asexual)
    95 (low) days
  • Range age at sexual or reproductive maturity (male)
    95 (low) days

This species has no parental investment.

  • Parental Investment
  • no parental involvement


A complete cycle of this species from egg to release of the next generation of eggs lasts from 106 to 172 days, provided at each stage the parasite is able to find its next host. However, the lifespan of an adult is unknown. (Olsen, 1986)


Flukes release their eggs and time their maturation to coincide with the availability of their intermediate snail hosts. Timing also coincides with the favorable environmental factors such as temperature and precipitation. However, it is unknown how environmental factors specifically induce or delay egg-laying and fluke maturation and how this mechanism is accomplished. Mature cercariae sense light with their two eyespots and emerge from their intermediate snail hosts during the daytime. Metacercariae excystment occurs when a change in physicochemical conditions is sensed, which allows them to excyst at the correct time inside the ruminant host. Adult flukes use topological features to guide their migration inside the rumen of the definite host. (Gupta, et al., 1984; Sukhdeo and Sukhdeo, 2004)

Communication and Perception

Mature cercariae have two eyespots capable of sensing light, as they need to emerge in the day to find a snail host. Excystment of metacercariae occurs when they sense the changed physicochemical conditions (such as temperature, substance concentration, and pH) inside the ruminant host, and adult flukes utilize topological features in the intestines of ruminants in order to guide their migration. The specific mechanisms of these behaviors are currently not well understood. Members of the species do not communicate amongst each other. (Sukhdeo and Sukhdeo, 2004)

Food Habits

Adults attach to the villi in the rumens of definitive ruminant hosts and sap nutrients from the intestine, although they can wander into the bile and pancreatic ducts, as do other trematodes. Sporocysts, rediae, and cercariae feed on the tissues and bodily fluids of the intermediate snail host. (Olsen, 1986)

  • Animal Foods
  • blood
  • body fluids


No specific predators are known for Paramphistomum cervi.

Ecosystem Roles

Adult livestock rumen flukes are the main parasites that occur in the rumen of cattle, sheep, goats, and buffaloes. However, mild infection is not seriously damaging to hosts. Large numbers of young flukes migrating throughout the intestine can cause acute parasitic gastroenteritis, likely leading to high morbidity and mortality. When paramphistomosis is diagnosed early in an animal, treatment can prevent the animal from suffering permanent damage to its rumen and bile ducts. Younger animals are more likely to succumb to paramphitomosis. (Boray, 1959)

Species Used as Host

Economic Importance for Humans: Positive

There are no known positive effects of Paramphistomum cervi on humans.

Economic Importance for Humans: Negative

Paramphistomum cervi causes severe economic losses to milk production since the flukes sap nutrients from their hosts, causing weight loss and a decrease in milk production. The parasite has become so prevalent that cattle mortality due to paramphistomosis has reached 80 to 90 percent in India, the Republic of South Africa, and Australia. The fluke also negatively impacts production in the wool and meat industries. (Castro-Trejo, et al., 1990; Rangel-Ruiz, et al., 2003)

Conservation Status

Paramphistomum cervi is currently not endangered. Efforts are underway to control the spread of the parasite among domesticated ruminants.


Yuching Lin (author), University of Michigan-Ann Arbor, Heidi Liere (editor), University of Michigan-Ann Arbor, John Marino (editor), University of Michigan-Ann Arbor, Barry OConnor (editor), University of Michigan-Ann Arbor, Renee Mulcrone (editor), Special Projects.



Living in Australia, New Zealand, Tasmania, New Guinea and associated islands.

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living in sub-Saharan Africa (south of 30 degrees north) and Madagascar.

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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.

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living in the northern part of the Old World. In otherwords, Europe and Asia and northern Africa.

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living in landscapes dominated by human agriculture.

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.

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


a period of time when growth or development is suspended in insects and other invertebrates, it can usually only be ended the appropriate environmental stimulus.


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


union of egg and spermatozoan


forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.


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.


(as keyword in perception channel section) This animal has a special ability to detect heat from other organisms in its environment.

internal fertilization

fertilization takes place within the female's body


marshes are wetland areas often dominated by grasses and reeds.


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.


found in the oriental region of the world. In other words, India and southeast Asia.

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reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.


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

scrub forest

scrub forests develop in areas that experience dry seasons.


remains in the same area


offspring are all produced in a single group (litter, clutch, etc.), after which the parent usually dies. Semelparous organisms often only live through a single season/year (or other periodic change in conditions) but may live for many seasons. In both cases reproduction occurs as a single investment of energy in offspring, with no future chance for investment in reproduction.


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


a wetland area that may be permanently or intermittently covered in water, often dominated by woody vegetation.


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).


Living on the ground.


the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.

tropical savanna and grassland

A terrestrial biome. Savannas are grasslands with scattered individual trees that do not form a closed canopy. Extensive savannas are found in parts of subtropical and tropical Africa and South America, and in Australia.


A grassland with scattered trees or scattered clumps of trees, a type of community intermediate between grassland and forest. See also Tropical savanna and grassland biome.

temperate grassland

A terrestrial biome found in temperate latitudes (>23.5° N or S latitude). Vegetation is made up mostly of grasses, the height and species diversity of which depend largely on the amount of moisture available. Fire and grazing are important in the long-term maintenance of grasslands.


uses sight to communicate


Boray, J. 1959. Studies on intestinal amphitomosis in cattle. Australian Veterinary Journal, 35: 282-287.

Castro-Trejo, L., Z. Garcia-Vasquez, J. Casildo-Nieto. 1990. The susceptibility of lymnaeid snails to Paramphistomum cervi infections in Mexico. Veterinary Parasitology, 35 (1-2): 157-161.

Gupta, B., V. Parshad, S. Guraya. 1984. Maturation of Paramphistomum cervi in sheep in India. Veterinary Parasitology, Volume 15: 239-245.

Kennedy, M., M. Lankester, J. Snider. 1985. Paramphistomum cervi and Paramphistomum liorchis (Digenea, Paramphistomatidae) in moose, Alces alces, from Ontario, Canada. Canadian Journal of Zoology, 63 (5): 1207-1210.

Olsen, O. 1986. Animal Parasites: Their Life Cycles and Ecology. New York: Dover Publications, Inc..

Rangel-Ruiz, L., S. Albores-Brahms, J. Gamboa-Aguilar. 2003. Animal Parasites: Their Life Cycles and Ecology. Seasonal trends of Paramphistomum cervi in Tabasco, Mexico, 116 (3): 217-222.

Sukhdeo, M., S. Sukhdeo. 2004. Trematode behaviours and the perceptual worlds of parasites. Canadian Journal of Zoology, 82: 292-315.