Fluke outbreaks in waterfowl – backyard poultry

By Doug Oettinger.

There are many parasites that can infect waterfowl. Among these is the flukes, a type of parasitic flatworm that belongs to the scientific class Trematodes. Most people are at least remotely aware of or have heard of liver flukes in sheep, cattle, and even humans. With around 24,000 species of flukes worldwide, there are fluke species that have the potential to invade almost any animal species imaginable, including mammals,
Fish, amphibians, reptiles and birds.

flukes types

There are many types of snakes that can affect waterfowl, but we’ll look at just three in this article. the first two types, Cyathocotyle bushiensis And Spheridiotrema ball, is the most common. This species invades the lower intestine, caecum, liver, bile ducts, and gallbladder of birds. It sticks to the walls of the small intestine after you eat it. Eventually, some travel through the bile ducts to the liver, where they cause inflammation and blockage of the ducts. And they are known too
to invade gallbladder. In the intestine, it sucks blood, impairs normal nutrient absorption, and impairs the host. Most cases lead to death.

Snails are infected by swimming, which matures in the snails. Waterfowl eat snails and swallow flukes. Snakes lay eggs in the guts of waterfowl, then release them into the water, starting the cycle again. Illustration by Carla Tilghman.

third type, Grali’s philophthalmos, commonly known as the bird’s-eye fold, invades and attaches to the eyelid membranes and conjunctival sacs of many bird species, including domestic and terrestrial waterfowl. They are found in both North and South America.

Forms and habits

Most flukes have a flattened body, a leaf-shaped head, and a sucking mouth with a ring of hooks surrounding it. They use these hooks to attach to the digestive tract, as well as the tissues and organs of their hosts.

The likelihood of a flock of ducks or geese becoming infected with these parasites is still fairly low in North America. The highest concentrations of this parasitic infection appear to be in Southeast Asia (including Myanmar, Bangladesh and Vietnam) and tropical areas with waterways
Wetlands are ideal breeding and nursery areas for these
parasites. However, burrowing species of waterfowl are also found in the northern United States, Canada, northern Europe, and other non-tropical regions of the world. Pierceminosis isn’t something you probably need to worry about a lot, but it’s something to be aware of.

For an animal that’s fairly simple in design, flukes have it
Quite a complex life cycle. Flukes requires an intermediary host
larval stages. In most cases, these intermediate hosts are water snails and slugs that live in waterways and wet and marshy grassland areas. In the tropics, dispersal and parasitic infestations occur throughout the year, while in areas with colder winters, reproduction often occurs in late summer after water warming. Waterfowl become infected after eating snails, which are parasitized by the developing larvae
flukes. As few as 100 flukes can be fatal to waterfowl. It is common for a single snail to contain more than 100 of these developing foraminifera. Death of a severely infected bird can occur within 3 to 8 days after infection with the parasites.

Signs and symptoms of a parasitic infestation can include weight loss, lethargy, loss of appetite, reduced and halted egg production, increased soft-shelled eggs, blood-stained holes, and of course the appearance of worms or flukes.

“Intermediate hosts” are species that host an immature form of the parasite. It catches European tap snails and piercing snails in fresh water and then drops more mature luck back into the water.

Host broker

In most cases, aquatic snails become an intermediate host, in which the larval stages of flukes grow and develop. one kind of snail, Bithynia
or European tap snail, is probably the most common
intermediate host and vector. Native to Europe, this gastropod has become invasive in many other regions of the world. However, it is not the only snail
able to become infected with the parasite and spread it. Field research conducted in the upper Mississippi River several years ago revealed that four separate species of snails were infected with both C. bushiness And S. globulus. In 1962, in southwestern Siberia, Russia, seven species of snails were infected with these worms.

Geographical distribution of birds of prey

Scientific studies and data on this topic have been inconsistent and irregular over the years. Research in Bangladesh in 2003 and 2004, during
300 domestic ducks were examined, and 69% were found to have flukes in their livers and gallbladders. Studies from Korea, Vietnam, and other duck-farming regions of Asia have also shown abnormally high concentrations of these parasites.

The warm tropical waterways and marshes in many of these areas provide optimal conditions for the snakes and their intermediate hosts.
Raising highly concentrated ducks in these areas, where the ducks feed on aquatic snails, creates the perfect recipe for catastrophic levels of infestation.

These parasites are by no means limited to Southeast Asia. Fatal and recurrent
Outbreaks of migratory waterfowl were recorded in southern Quebec between 1968 and 1988. Occasional findings have also been found on all major flight paths in North America. The potential risk of bird carcass decline in native North American waterfowl is greater in areas where domestic birds and wild birds may share a common pasture or pond.

accidents P.Gralli, the most common bird’s-eye coop, is also on the rise. There have been increased field results in the North Pacific flight path
America and its increasing incidence in South America. This may be a parasite
They are spread via common bird migration routes.

Flukes life cycles

New infestations of intestinal liverworms often begin when an infected waterfowl releases fluvial eggs into water or swamps via fecal secretions. Fluke eggs hatch immediately once in the water, thus entering the first larval stage. Known as miracidia, these free-swimming creatures are known to invade a water snail or slug, taking several months to develop and reproduce asexually many times into a second larval stage known as cercariae. These organisms eventually leave their host and invade another water snail or other water slug, adapting there in a form known as metacercariae. When waterfowl eat snails infested with these metacercariae, the parasites attach themselves to the intestinal tract, where they mature and begin laying eggs. The newly infected birds then excrete the eggs into the water with their feces, and the cycle begins again.

In the case of a pierced eye in sex philophthalmus, the life cycle is similar, but only one stage of the intermediate host is involved. The larvae of the cercariae attach themselves to aquatic plants, where they form a protective shell around themselves. When the bird ingests aquatic plants, the cercariae break free from their protective envelope and attach themselves to the mucous membranes and conjunctival sacs surrounding the bird’s eyes. There, the cercariae suck blood, multiply, and cause severe irritation to their host. Free swimming
The cercariae may also attach directly to the conjunctiva when the birds put their heads under water.

While avoiding parasites and diseases may not always be possible, regularly check your birds for any signs of infection or injury and, if possible, keep wild waterfowl away from common areas. This can help avoid sporadic diseases and parasitic infestations.

Doug Oettinger He lives, works, and writes from his small hobby farm
Northwest Minnesota. Doug’s educational background is in agriculture
With an emphasis in poultry and bird science.

Originally published in the June/July 2023 issue of Backyard poultry Journal and is regularly checked for accuracy.

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