Reported from cattle in India, Sri Lanka, Philippines, Bangladesh, Mexico,
and mainly tropical regions worldwide.
Mecistocirrus digitatus is considered one of the most
prevalent trichostrongylid parasites of cattle; it causes losses in
production worlwide.
Cattle
Intestinal parasites of cattle.
Lif cycle direct as in other trichstrongylids.
The following life history is derived from the intensive studies
conducted during the PhD research of Fernando (1965).
- Eggs cultured in ruminant host (cattle) fecal material
hatch ibetween 24 and 30 hours. First-stage larvae are around 500 mu
long, the mouth has two lips and a delicate, narrow buccal tube and
rhabditiform esophagus.
- Molting to the 2nd stage begins between 60 and 70 hours and to
the third stage at 150 hours. Third stage larvae (550-780 mu long)
are ensheathed in the second stage cuticle.
- Presumably eggs and early larval stages are ingested by grazing
ruminants. The third-stage larva are the first parasitic stage and
enter the mucosa of the abomasum and and migrate into gastric pits
and interglandular tissues of the lamina propria. The 3rd
stage larvae feed, the intestine becomes wider and cells are laden
with bownish globules; the genital primordia begin to enlarge.
- Fourth-stage larvae are evident by 9 days after infection and
sexes can be distinguished on the basis of genital primordia
development. Lengths of the fourth stage larvae are 1.5-1.8 mm
(males) and 2-2.3 mm (females).
- By the 28th day after infection, the majority of larva have
entered the 5th stage, earlier cuticle sheaths have been shed and
the bursa is evident in males. Males at this stage are 7.9 to 9.3 mm
long and females 8.5 to 10.1 mm.
- By 60 days after infection the larvae have all become
adults with males 18-22 mm long and 0.4 mm wide, females 20-24 mm
long and 0.4 mm wide.
- Eggs can be detected in feces of host animals between 54
and 70 days after infection.
Ivermectin treatment of calves is effective
(Mendoza de-Gives, P., Fuentes, R.N. 1987).
Fernando, S.T. 1965.
The Life Cycle of Mecistocirrus digitatus, a Trichostrongylid Parasite of
Ruminants. J. Parasitology 51:156-163.
Mendoza de-Gives, P., Fuentes, R.N. 1987.
Efficacy of ivermectin against the abomasal nematode Mecistocirrus
digitatus in naturally infected zebu calves. American
J. Vet. Research 48:1611-1612.
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