Mecistocirrus spp

From Cow
Mecistocirrus spp adult, posterior end

Mecistocirrus spp are a common large haematophagous parasitic nematode of cattle worldwide.

Mecistocirrus spp are a major cause of economic losses in the livestock industry because they impair weight gain and increases mortality in cattle, especially in temperate areas[1].

Species recognized as pathogenic in cattle include:

  • Mecistocirrus digitatus

The life cycle of Mecistocirrus spp is relatively short with a prepatent period of 4 - 6 weeks. Eggs develop slowly and the infective larvae are reached within the egg in 2 – 4 wk and may remain within the egg for several months. After ingestion, adults mature within a month. Infections with M. digitatus significantly affects a subsequent challenge infection. Stimulation of the immune system by exposure to infective larvae extends the pre-patent period, and suppression by later stages leads to higher worm burdens[2].

Clinical signs associated with this parasite are characterized by diarrhea. Anemia is sometimes observed concurrently.

Diagnosis is based on presenting clinical signs and confirmation of eggs in fecal samples[3]. PCR assays are also available commercially to assist diagnosis[4].

A differential diagnosis would include Ostertagia spp, Oesophagostomum spp, Nematodirus spp and Cooperia spp.

Treatment is effective with most oral and topical anthelmintics. Resistance to benzimidazoles and avermectins are commonly reported[5].

References

  1. Stancampiano L et al (2007) Parasites of the digestive tract in beef cattle imported from France to Italy. Parassitologia 49(1-2):101-106
  2. Van Aken D et al (1998) Development of immunity to Mecistocirrus digitatus (Nematoda: Trichostrongylidae) in calves. Parasitology 117(1):83-87
  3. Keyyu JD et al (2005) Epidemiology of gastrointestinal nematodes in cattle on traditional, small-scale dairy and large-scale dairy farms in Iringa district, Tanzania. Vet Parasitol 127(3-4):285-294
  4. Mochizuki R et al (2006) PCR-based species-specific amplification of ITS of Mecistocirrus digitatus and its application in identification of GI nematode eggs in bovine faeces. J Vet Med Sci 68(4):345-351
  5. Canul-Ku HL et al (2012) Prevalence of cattle herds with ivermectin resistant nematodes in the hot sub-humid tropics of Mexico. Vet Parasitol 183(3-4):292-298