Encyclopedia of Parasitology

2016 Edition
| Editors: Heinz Mehlhorn

Oesophagostomum Species

Reference work entry
DOI: https://doi.org/10.1007/978-3-662-43978-4_2191

Name

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.

Geographic Distribution/Epidemiology

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 %.

Morphology/Life Cycle

Important Oesophagostomum species are
  1. 1.

    O. dentatum, O. quadrispinulatum in pigs and boars

     
  2. 2.

    O.venulosum, O. radiatum, O. columbianum in ruminants

     
  3. 3.

    O. bifurcatus in monkeys and humans

     
The adult worms appear yellow white and live mainly in the colon but also in the cecum, where they induce name-giving nodule formation (Fig. 1). The males measure 6–17 mm in length, while the females reach up to 24 mm. Their mouth capsules are short and rather broad, being surrounded by one or two rows of fine teeth (Figs. 2 and 3). Males bear a bursa copulatrix at their terminal pole comprising two spicula, the gubernaculum, and several fortifying bursa spines. Females deposit unembryonated thin-shelled eggs which belong to two groups:
Oesophagostomum Species, Fig. 1

Macrophoto of nodules (arrows) due to an infection with Oesophagostomum radiatum

Oesophagostomum Species, Fig. 2

Diagrammatic representation of the anterior ends of Oesophagostomum species. From left: O. radiatum (cattle); O. venulosum (sheep, goats); O. dentatum (pigs). D = intestine; LP = lips; OE = oesophagus; SP = sensory papilla

Oesophagostomum Species, Fig. 3

Scanning electron micrograph of an adult stage of Oesophagostomum. LF = lateral wing

  • 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.

Diagnosis

Microscopic demonstration of eggs by help of concentration methods (e.g.,  flotation; S.A.F.C.). Identification of species is best done if cultured larvae 3 are studied. See Fig. 1 in Infectious larvae of nematodes.

Infection

Oral uptake of infectious larvae 3.

Prophylaxis

Rotation of pasture use.

Incubation Period

Five to seven days.

Prepatent Period

Species specific two to six weeks.

Patency

Two to six months.

Therapy

See Nematocidal drugs, animals.

Further Reading

  1. Joachim A et al (1997) Use of random amplified polymorphic DNA-polymerase chain reaction for the definition of genetic markers for species and strains of porcine Oesophagostomum. Parasitol Res 83:646–654CrossRefPubMedGoogle Scholar
  2. Ondrovicy M et al (2013) Proteomic analysis of Oesophagostomum dentatum during larval transition. PLoS One 8(5):e63955CrossRefGoogle Scholar
  3. Petersen HH et al (2014) Parasite population dynamics in pigs infected with Trichuris suis and Oesophagostomum dentatum. Vet Parasitol 199:73–80CrossRefPubMedGoogle Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 2016

Authors and Affiliations

  1. 1.Institut für Zoomorphologie, Zellbiologie und Parasitologie, Heinrich-Heine-UniversitätDüsseldorfGermany