Greek: stoma = mouth. Latin: oesophagus = oesophagus; dentatus = with teeth; radiates = radiating; venulosus = in veins; bifurcatus = with two terminal spikes; quadrispinulatus = with four spines. English: nodular worms.
Worldwide. Human cases due to O. bifurcatus in West Africa (Togo, Ghana), which normally occurs in monkeys, have a considerable local medical importance. In European pig farms, Oesophagostomum worms reach prevalence rates of up to 80 %.
O. dentatum, O. quadrispinulatum in pigs and boars
O.venulosum, O. radiatum, O. columbianum in ruminants
O. bifurcatus in monkeys and humans
50–80 μm × 25–45 μm (O. dentatum, O. quadrispinulatum)
60–100 μm × 40–60 μm (O. radiatum, O. venulosum).
All Oesophagostomum species do not suck blood. The eggs produce on the meadow the larva 1, which hatches from the egg and develops within 6–8 days into the infectious larva 3. If these larvae 3 are ingested, most of them reach maturity without any waiting stage within 6 weeks. Some of the larvae, however, are enclosed in nodules (3–10 mm in diameter, Fig. 1). These hypobiotic larvae start their development into maturity only when the first adults have been discharged from the intestine (due to self-healing or due to chemotherapy). They thus act like a “reserve pool.”
Symptoms of Disease
Depending on the amount of worms, the animals show retarded growth, loss of weight, and bad reproduction besides slimy diarrheas. In the case of infections of monkeys and humans, severe inflammations of the colon may occur. Some cases ended fatal. Repeated infections of animals, however, lead to protection from severe symptoms.
Oral uptake of infectious larvae 3.
Rotation of pasture use.
Five to seven days.
Species specific two to six weeks.
Two to six months.
See Nematocidal drugs, animals.