Amoebotaenia cuneata (= Amoebotaenia sphenoides) is a parasitic tapeworm that has chicken and other domestic and wild gallinaceous birds (e.g. turkey, pheasants, quails, etc.) as final hosts.
They are found worldwide, with variable incidence, but are less frequent than other parasitic tapeworms of birds (e.g. Davainea proglottina, Raillietina spp). Other species of the genus Amoebotaenia affect mainly wild birds.
Amoebotaenia cuneata does not affect dogs, cats, cattle, sheep, pigs, horses and other domestic mammals.
Are birds infected with Amoebotaenia cuneata contagious for humans?
NO. The reason is that this tapeworm species is not a human parasite.
Final location of Amoebotaenia cuneata
The predilection site of adult Amoebotaenia cuneata is the small intestine
Anatomy of Amoebotaenia cuneata
Adult tapeworms are very small, not longer than 4 cm. The anterior part has a triangular shape. The head (scolex) has suckers and 12 to 14 hooks for attaching to the host's gut wall. Usually it has not more than 25 segments (proglottids), which are wider than long. Each segment has its own reproductive organs of both sexes (i.e. they are hermaphroditic). Each segment has also excretory cells known as flame cells (protonephridia).
The reproductive organs in each segment have a common opening called the genital pore. In young segments all these organs are still rudimentary. They develop progressively, which increases the size of the segment as it is pushed towards the tail.
Otherwise, as other tapeworms, they have neither a digestive tube, nor circulatory respiratory systems. They don't need them because each segment absorbs what it needs directly through its tegument.
The eggs are almost spherical, about 35 micrometers in diameter and contain an embryo (oncosphere).
Life cycle and biology of Amoebotaenia cuneata
Amoebotaenia cuneata has an indirect life cycle with domestic and wild birds as final hosts, and earthworms (e.g of the genus Lumbricus) as intermediate hosts.
The gravid segments of adult tapeworms that contain the eggs are shed with the birds' feces. They are motile and migrate quickly odd the feces into the surrounding vegetation. The earthworms ingest the gravid segments, which release the eggs in their gut after digestion. The eggs then develop to cysticercoids in the body cavity of the earthworms. The birds ingest such contaminated earthworms and after digestion, the cysticercoids release the young tapeworms that attach to the wall of the bird's gut.
The time between infection and shedding of the first eggs (prepatent period) is about 4 weeks. In Europe Amoebotaenia infections are seasonal, mainly between january and may, probably associated with the maximum availability of earthworms for the birds.
Harm caused by Amoebotaenia cuneata, symptoms and diagnosis
Amoebotaenia cuneata infections are usually benign and cause no clinical signs. Massive infections can cause reduced growth in young birds. Infections with more than 200 worms can cause enteritis, occasionally with hemorrhage. Affected birds can become apathetic and isolated.
Diagnosis is done through detection of gravid segments in the feces. Fecal examination must be done on fresh feces, because the gravid segments migrate quickly outside the droppings. Eggs are usually not found in the feces because they remain inside the migrating gravid segments. After necropsy the adult worms can be seen as whitish projection of the intestinal villi.
Prevention and control of Amoebotaenia cuneata
Frequent change of the birds' bedding and keeping it dry can help to avoid infections because it shortens the survival of the eggs and is unattractive for earthworms. Free-ranging birds should be kept off humid environments that are supportive of earthworms.
Flocks at risk can be treated with anthelmintics effective against tapeworms. They contain either broad-spectrum benzimidazoles (e.g. albendazole, febantel, fenbendazole, mebendazole, oxfendazole, etc.) or specific taenicides (e.g., niclosamide, praziquantel, etc.). Most of these active ingredients are available as additives for feed or drinking water, or as tablets for oral delivery.
WARNING: niclosamide is toxic for geese, and the combination of praziquantel with pyrantel tartrate is toxic for chicken!
Other classic livestock anthelmintics such as macrocyclic lactones (e.g. ivermectin, doramectin, moxidectin, etc.), levamisole, tetrahydropyrimidines (e.g. pyrantel, morantel) and piperazine derivatives are not effective at all against Amoebotaenia or whatever tapeworm.
There are so far no vaccines against Amoebotaenia. To learn more about vaccines against parasites of livestock and pets click here.
Biological control of Amoebotaenia tapeworms (i.e. using its natural enemies) is so far not feasible.
You may be interested in an article in this site on medicinal plants against external and internal parasites.
Resistance of Amoebotaenia to anthelmintics
So far there are no reports on resistance of Amoebotaenia tapeworms to anthelmintics.
This means that if an anthelmintic fails to achieve the expected efficacy, chance is very high that either the product was unsuited for the control of Amoebotaenia tapeworms, or it was used incorrectly.
Ask your veterinary doctor! If available, follow more specific national or regional recommendations for Amoebotaenia control.