Synonyms

No known synonym

Name of the disease in English

Fascioliasis - fasciolosis

The disease in brief

It is caused by the presence in the bile ducts of Fasciola hepaticaIt is a very common condition in this chronic form, but which manifests itself little clinically. F. hepatica causes chronic cholangitis which intensifies with repeated contact with the parasite each year; they are also the cause of hepatic fibrosis.

Parasitized cattle produce less, lose weight and may have reproductive problems more often. This damage is economically important over time, but it is not very characteristic and the disease often goes unnoticed by the clinician; only pastures in wet areas regularly raise suspicion of the disease.

Cycle: Fasciola adult lays eggs which arrive, via the bile, in the intestine and are evacuated in the dung; from these eggs hatch miracidium, a mobile larva, which will infest a truncated Limnea, a small gastropod of humid places. The miracidium evolve in the limnea into mobile metacercariae which in turn leave the Limnea to become encysted in metacercaria, an infesting form stuck on the grass, swallowed by the ruminants. Metacercariae ingested with the herb pass through the intestinal wall and, via the peritoneal cavity, reach the liver. A humid environment is essential at all stages of the cycle; two periods of infestation are observed: a limited one in spring (except in marsh areas) and a greater one in late summer-autumn.

Clinic & diagnosis

The disease is suspected from the symptoms but also from the circumstances:

-Symptoms: A conjunctival or vaginal mucosa paler than normal, or slightly jaundiced with normal ruin, or edema of the trough or entrance to the chest (bottle sign).

-Risk circumstances: The cattle are on a wet pasture, or are in the stable but stay in a wet zone (marshy meadows; ponds or streams accessible for watering; accessible ditches); wetlands are often visited in late summer after the drought period.

Fascioliasis is often suspected during winter diarrhea but this sign is not at all characteristic and is most often due to other parasites (digestive strongyles) or intestinal infections such as paratuberculosis.

Typical sign of the disease

No description

Pictures

See below

Diagnostic formulas

No description

Differential diagnosis

-N72 copper deficiency

-N71 cobalt deficiency

-Paratuberculosis DG44

-Polyparasitism-strongylosis-large fluke Or paramphistomosis PA10.1

Confirm a suspicion?

Faced with a clinical suspicion (anemia, edema): the coproscopy is reliable because in this case the infestation is always high

Faced with an epidemiological suspicion (grazing in a wet area possibly associated with insufficient performance): collect blood on a dry tube from a batch of suspect cattle and have an Elisa serological test carried out in the laboratory.

Prognosis and treatment

Animals that are in the stage of hepatic fibrosis will not be able to recover normal liver function. Improvement of their condition is possible, but will be conditioned on the absence of new contact with the parasite.

The treatment must be collective and can be done by different means:

Triclabendazole orally is very effective on all stages of the parasite (12 mg / kg bodyweight). Nitroxynil (injectable), clorsulon (oral or injectable) are effective on the adult and immature stages of more than 4 to 6 weeks.

Only oxyclozanide and albendazole can be used in dairy animals (with milk withdrawal time) but they only have an effect on the adult stages.

Prevention

Prevention must be the priority for all herds which aim for good productivity.

It is based on the prohibition of grazing wetlands, wherever possible (agronomic prevention) and the treatment of animals as early as possible after infestation when possible; this therapeutic prevention aimed at limiting losses is easy in lactating breeding but very imperfect in dairy breeding (adulticidal molecules only and waiting time).

References

-Veterinary Medicine-Pocket companion -9th Edition BLOOD DC-page 496