Dog hookworm

Ancylostoma caninum

ORDER

Strongylida

FAMILY

Ancylostomatidae

TAXONOMY

Sclerostoma caninum (Ercolani, 1859), originally Sclerostoma Ca-nis familiaris, Europe.

OTHER COMMON NAMES

English: Creeping eruption (when found in humans).

PHYSICAL CHARACTERISTICS

The most widespread of the hookworm species, they target dogs and other canids. Male adults are 0.43-0.55 in (1.1-1.4 cm) in length, with a copulatory bursa, two large lateral lobes, and two equal filiform spicules; females 0.5-0.8 in (1.3-1.9 cm) in length, with no vulvular flap. Adults have an anterior end that is bent dorsally, a buccal capsule that is deep and supported by thick cuticle, three pairs of teeth (three on each side of the ventral margin) that are located at the anterior stoma, and a strongyliform esophagus. They are often red in color because of the blood in their gut; otherwise, they are gray in color. Their heads "hook" into the small intestines of the host, where they begin to eat away at the tissue and suck blood. Eggs are 0.00209-0.00272 in (53-69 pm) by 0.00142-0.00209 in (36-53 pm), ovoid-shaped, and thin-shelled embryos. The first-stage larvae have a mouth tube, bulbed rhabditiform esophagus, and straight tail. No genital rudiment is visible.

DISTRIBUTION

Found in eastern Asia, Central and South America, and Australia. (Specific distribution map not available.)

HABITAT

Generally live in temperate forests and rainforests, temperate grasslands, tropical deciduous forest, tropical rainforests, and tropical scrub forests. Within the host, they live within the small intestines of dogs and other canids, and can also live in foxes and cats. They can also live under the skin of humans.

BEHAVIOR

Intermediate hosts are generally not present, however, paratenic hosts (hosts that act as transfer hosts where the parasite does not develop) are normally encountered. The first eggs appear 60-75 days after the initial exposure. On reaching the small intestine, they proceed to develop to adult males and females. They suck the blood and tissues; both the plasma and corpuscles undergo at least partial digestion. In some cases, some larvae may go dormant, but can be reactivated later by unknown means.

FEEDING ECOLOGY AND DIET

As parasites, feeds off its hosts. In the free-living larvae stage, they feed on organic matter.

REPRODUCTIVE BIOLOGY

Dioecious; following copulation, females lay eggs in the intestines of the host. Females lay 7,000-30,000 eggs per day. The embryonated eggs are carried out in the host's feces. Eggs develop in the soil/feces under favorable environmental conditions of moisture, oxygen, and temperature. About three weeks later, the juveniles are unsheathed, non-feeding, and infective. When they reach the small intestine of the host, they molt a final time and develop to maturity in about five weeks.

CONSERVATION STATUS Not listed by the IUCN.

SIGNIFICANCE TO HUMANS

In humans, the infection of the species is called "creeping eruption," and causes a severe rash. This species causes disease primarily in puppies; in its severest form, the disease is life threatening to puppies and sometimes to adult dogs. ♦

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