Echinococcus spp

From Cow
Echinococcus granulosus adult

Echinococcus spp are a group of parasitic cestodes which causes hydatid cysts in cattle worldwide.

Species recognised in cattle include:

  • Echinococcus granulosus
  • Echinococcus ortleppi[1]
  • Echinococcus pancreaticum[2]

The life cycle involves extra-intestinal migration in the intermediate host and formation of an hydatid cyst. When the cat eats the intermediate host, ingests the hydatid cyst, the protoscolices attach to the small intestinal wall and the worms begin to form proglottids. Gravid proglottids, containing the eggs, detach from the end of the worm and spill their eggs into the lumen of the intestine. The eggs pass out in the feces. The prepatent period is less than 40 days. Zoonotic infections to humans occur commonly[3].

After hatching in the intestine of the cattle, the oncospheres invade the circulatory system and lodge in various organs (the liver and lungs), where they develop into large, thick-walled, unilocular hydatid cysts that bud protoscolices endogenously. Hydatids have been rarely reported in the brain of cattle[4].

Diagnosis is determined by postmortem findings of hydatid cysts, and fecal examinations showing oocysts[5].

Vaccinations of cattle with subunit vaccines afford up to 99% protection against infection[6].

Treatment against individual affected cattle is effective when using praziquantel[7].

References

  1. Balbinotti H et al (2012) Echinococcus ortleppi (G5) and Echinococcus granulosus sensu stricto (G1) loads in cattle from Southern Brazil. Vet Parasitol 188(3-4):255-260
  2. Roy B & Tandon V (1992) Seasonal prevalence of some zoonotic trematode infections in cattle and pigs in the north-east montane zone in India. Vet Parasitol 41(1-2):69-76
  3. Reperant LA et al (2009) Rodents as shared indicators for zoonotic parasites of carnivores in urban environments. Parasitology 136(3):329-337
  4. Merck Vet Manual
  5. Peter MS (2006) Progress in diagnosis, treatment and elimination of echinococcosis and cysticercosis. Parasitol Int 55:7–13
  6. Heath DD et al (2012) Vaccination of bovines against Echinococcus granulosus (cystic echinococcosis). Vaccine 30(20):3076-3081
  7. David H et al (2006) Control of hydatidosis. Parasitol Int 55:247–252