Toxocara canis

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Toxocara canis
Adult Toxocara canis
Adult Toxocara canis
Scientific classification
Kingdom: Animalia
Phylum: Nematoda
Class: Secernentea
Order: Ascaridida
Family: Toxocaridae
Genus: Toxocara
Species: T. canis
Binomial name
Toxocara canis
Werner 1782

Toxocara canis (also known as dog roundworm) is worldwide distributed helminth parasite of dogs and other canids. T. canis are gonochorists, adult worms measure from 9 to 18 cm, are yellow-white in color, and occur in the intestine of the definitive host. In adult dogs, the infection is usually asymptomatic. By the contrast, massive invasion of T. canis can be fatal in puppies.[1] [2] As paratenic hosts, a number various vertebrates, including man, and some invertebrates can become infected. Humans are infected, like other paratenic hosts, by ingestion embryonated T. canis eggs.[3] The disease caused by migrating T. canis larvae (toxocariasis) results in two syndroms: visceralis larva migrans and ocularis larva migrans.[4] Owing to transmission of the infection from bitches to puppies, preventive anthelmintic treatment of newborn puppies is strongly recommended. Several anthelmintic drugs are effective against adult worms, for example pyrantel, fenbendazole, selamectine etc.[5]

What is Toxocariasis?[6] Toxocara canis causes the parasitic disease toxocariasis which includes two major forms:

  1. Ocular larva migrans (OLM): Toxocara infections may cause OLM, which is an eye disease that leads to blindness. OLM occurs when a microscopic worm enters the eye and causes inflammation and formation of a scar on the retina. On average, more than 700 people are infected with Toxocara and experience permanent partial loss of vision each year. Treatment of OLM is more difficult and usually consists of measures to prevent progressive damage to the eye.
  2. Visceral larva migrans (VLM): This is a rare heavier form of toxcara infections that can cause VLM. VLM is a disease that causes swelling of the body's organs or central nervous system. Symptoms include fever, coughing, asthma, or pneumonia which is caused by worms moving through the body. VLM is treated with antiparasitic drugs, usually in combination with anti-inflammatory medications.


[edit] Morphology

Adult T. canis have round body with spiky cranial and caudal part, covered by yellow cuticula. Cranial part of the body contains two lateral alae (length 2–2.5 mm, width 0.2 mm). Male worms measure 9–13 × 0.2–0.25 cm and female worms 10–18 × 0.25–0.3 cm. T. canis eggs have oval or spherical shape with granulated surface, thick-walled, and measures from 72 to 85 μm.[1]

[edit] References

  1. ^ a b Svobodová V, Svoboda M (1995). Klinická parazitologie psa a kočky. ČAVLMZ. 
  2. ^ Jurášek V, Dublinský P, et al (1993). Veterinárna parazitológia. Príroda a.s.. ISBN 80-07-00603-6. 
  3. ^ Gillespie SH (1988). "The epidemiology of Toxocara canis". Parasitol Today 4 (6): 180–182. doi:10.1016/0169-4758(88)90156-1. PMID 15463080. 
  4. ^ Despommier D (2003). "Toxocariasis: clinical aspects, epidemiology, medical ecology, and molecular aspects". Clin Microbiol Rev 16 (2): 265–272. doi:10.1128/CMR.16.2.265-272.2003. PMID 12692098. 
  5. ^ The Merck Veterinary Maual

6. CDC webpage. Division of Parasitice Disease. 2007. http://www.cdc.gov/ncidod/dpd/parasites/toxocara/factsht_toxocara.htm

[edit] External links

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