Uncinaria stenocephala

Lifecycle

The host ingests an infective third-stage larva. The larva matures to the adult in the small intestine. Eggs are laid in the small intestine and pass out with the feces. The prepatent period is about 15 to 17 days. The eggs hatch in the soil and the larvae molt twice to reach the infective third stage. Infections worsen and amplify when dogs that are regularly kept outside are not routinely dewormed.

Adult worms may live for 4 to 24 months in the small intestine. Dog and cat hookworms range in size from 10 to 20 mm by 0.4 to 0.5 mm and the eggs are 71 to 93 μm by 35 to 58 μm.

Adult parasites are most often found in their hosts' small intestine. A second type of infection occurs with transdermal larval infection into the dog's skin, usually made possible by warm weather and humidity, which allows the larvae to grow in the environment. These transdermal infections are not very significant in U. stenocephala because about 2.3 ± 1.3% of infective larvae actually reach the small intestine to finish its lifecycle.

Diagnosis

Diagnostic stage:

• Eggs are found in fecal flotation (diagnostic).
• Eggs measure 75 um long by 45 um wide.

Clinical signs:

• U. stenocephala ingests plasma protein rather than whole blood, so the loss of nutrients is evident.
• All hookworms suck blood; they are capable of removing 0.1 ml of blood per worm, per 24-hour period.
• Light infections are asymptomatic.
• Infected pups may present with pale mucous membranes and anemia, ill thrift, failure to gain weight, poor hair coat, dehydration, and dark, tarry diarrhea (melena). Puppies harboring many worms develop an acute normocytic, normochromic anemia followed by hypochromic, microcytic anemia due to iron deficiency. Without immediate intervention, these animals may die of the infection. Those that survive may continue as "poor doers" with chronic anemia.

U. stenocephala is considered a zoonotic hookworm and can cause a few different diseases in humans, including cutaneous larva migrans. Humans become infected when the larvae penetrate unprotected skin due to contaminated animal feces in the environment.

Treatment and prevention

Effective treatment of U. stenocephala includes proper medical treatment and the proper choice of anthelmintic (febantel, febantel/pyrantel embonate, fenbendazole, ivermectin, mebendazole, pyrantel pamoate). Infected animals are recommended to have their feces examined three weeks after treatment is complete. Heartworm prevention products that include ivermectin/pyrantal/praziquantel or Moxidectin are good at controlling U. stenocephala in dogs.

References

References

1. "Hookworms in Small Animals - Digestive System".
2. "Canine hookworm dermatitis (uncinariasis)".
3. (2019-04-25). "CDC - Zoonotic Hookworm".
4. "Intestinal Parasites - Hookworms". Companion Animal Parasite Council.
5. (August 2013). "Hookworm dermatitis due to ''Uncinaria stenocephala'' in a dog from Saskatchewan". The Canadian Veterinary Journal.
6. (1979-10-01). "Enige epidemiologische aspecten van Uncinaria stenocephala infectie in Nederland". Tijdschrift voor Diergeneeskunde.
7. (2006). "''Uncinaria stenocephala'': Assessment of antigens for the immunodiagnosis of canine uncinariosis". Experimental Parasitology.