Gnathostoma spp

From Dog
Eggs of G. nucleatum under light microscopy[1]
Necropsy findings in a dog with G. binucleatum showing gastric nodule, splenomegaly and hepatomegaly[1]

Gnathostoma are an uncommon parasitic nematode of the canine stomach[2].

These parasites are found in North Africa, India, South-East Asia and Australia, and encyst in nodules within the gastric lining, espceially in the greater curvature of the stomach[3]. The prevalence and worm burdens of Gnathostoma exhibit seasonal fluctuation in rural environments[4].

Copepods are the paratenic host[5] and estuarine fish, turtles[6], opossums and raccoons[7] act as intermediate and paratenic hosts.

Larval migration through visceral organs occurs, especially the liver. Ruptured nodules can result in gastric bleeding or peritonitis. Aberrant migrations to peripheral lymph nodes can also occur in dogs[8].

Species which are pathogenic to dogs include:

  • Gnathostoma spinigerum
  • Gnathostoma procyonis
  • Gnathostoma binucleatum[1]

Clinical signs are usually vague, but acute gastritis can occur, with anorexia, fever and weight loss evident.

Diagnosis is usually based on coprological evidence of Gnathostoma eggs[9].

Treatment is usually effective with ivermectin or milbemycin oxime.

References

  1. 1.0 1.1 1.2 Alvarez-Guerrero C et al (2011) Gnathostoma binucleatum: pathological and parasitological aspects in experimentally infected dogs. Exp Parasitol 127(1):84-89
  2. Hinz E (1980) Intestinal helminths in Bangkok stray dogs and their role in public health. Zentralbl Bakteriol Mikrobiol Hyg B 171(1):79-85
  3. Bowman, DD (2009) Georgis' parasitology for veterinarians. 9th edn. Elsevier Saunders, Missouri. pp:319
  4. Maleewong W et al (1992) Seasonal variation in the prevalence and intensity of canine Gnathostoma spinigerum infection in northeastern Thailand. J Helminthol 66(1):72-74
  5. Rojekittikhun W et al (2002) Gnathostoma infection in Nakhon Nayok and Prachin Buri, Central Thailand. Southeast Asian J Trop Med Public Health 33(3):474-484
  6. Guerrero CA & Alba-Hurtado F (2007) Estuarine fish and turtles as intermediate and paratenic hosts of Gnathostoma binucleatum in Nayarit, Mexico. Parasitol Res 102(1):117-122
  7. Diaz Camacho SP et al (2002) Morphology of Gnathostoma spp. isolated from natural hosts in Sinaloa, Mexico. Parasitol Res 88(7):639-645
  8. Bate M et al (1982) Gnathostoma spinigerum in a dog's leg. Aust Vet J 60(9):285-286
  9. Vonghachack Y et al (2010) Sero-epidemiological survey of gnathostomiasis in Lao PDR. Parasitol Int 59(4):599-605