Capillaria spp

From Cow
Capillaria spp egg under light microscopy
Adult Capillaria spp worm

Capillaria spp (syn: Pearsonema spp) are a common haematophagous parasitic nematode of cattle worldwide[1].

Capillaria 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[2].

Species recognized as pathogenic in cattle include:

  • Capillaria bovis[3]

The life cycle of Capillaria spp is relatively complex. Eggs can be ingested from the soil or from carcasses of dead animals. Infective larvae hatch in the cecum, penetrate the mucous membrane and reach the portal system where they lodge in the hepatic parenchyma. These parasites may also be found in the lung and kidney.

After 1 month, they mature to adult. Fertilized eggs are ingested by prey[4].

Clinical signs associated with this parasite are characterized by parasitic hepatitis, nephritis and pneumonitis. Anemia and icterus are sometimes observed concurrently[5], especially in young calves that can die from emaciation.

Bovine parasitic hepatitis is characterized by multiple small yellowish lesions. Histologically, the degenerative lesions show eosinophilic papillary endothelial hyperplasia of the interlobular veins and eosinophilic membranous structures in the eosinophilic granulomatous areas of inflammation. These characteristic findings have been found in 5 - 20% of milk cows in Japan and Australia[6].

Diagnosis is based on presenting clinical signs and confirmation of eggs in fecal samples[7].

A differential diagnosis would include other causes of liver disease such as hepatic lipidosis, and parasites such as Ostertagia spp, Oesophagostomum spp and Cooperia spp[8].

Treatment is effective with most oral and topical anthelmintics. Resistance to benzimidazoles and avermectins are commonly reported[9].

References

  1. Theodoropoulos G et al (2010) Survey of gastrointestinal parasitic infections of beef cattle in regions under Mediterranean weather in Greece. Parasitol Int 59(4):556-559
  2. Stancampiano L et al (2007) Parasites of the digestive tract in beef cattle imported from France to Italy. Parassitologia 49(1-2):101-106
  3. Borgsteede FH et al (2000) Nematode parasites of adult dairy cattle in the Netherlands. Vet Parasitol 89(4):287-296
  4. Collier L et al (1998) Strongyloides and Capillaria. In Toplye's Microbiology and Microbial Infections. Volume V. 9th edition. Edited by Topley, Wilson. New York: Oxford University Press; pp:585-595
  5. Merck Vet Manual
  6. Nakamura N (2005) Parasitic lesions of bovine liver attributed to capillaria species. J Comp Pathol 132(2-3):228-231
  7. 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
  8. Khan MN et al (2010) Gastrointestinal helminthiasis: prevalence and associated determinants in domestic ruminants of district Toba Tek Singh, Punjab, Pakistan. Parasitol Res 107(4):787-794
  9. 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