Hyostrongylus rubidus: Red stomach worm

General Description: The slender adult worms, 0.5 to 1cm. Long, are bright red when fresh because of their blood-sucking feeding habits. Typical "strongyle-type" eggs are laid.

Life Cycle: Stomach worm eggs are passed in the faeces. :Larvae hatch and develop to the infective, ensheathed third stage in a week. These larvae are not very resistant to cold or drying. After being eaten by a pig, the larvae enter the pits of gastric glands, where they may remain in the histotropic larval phase for 13-14 days. Some larvae will emerge into the lumen of the stomach. Some larvae can remain in the inhibited state in the gastric glands for several months, dilating the glands and forming nodules. Egg laying begins 3 weeks after infection.

Location: Stomach.

Geographical Distribution: Worldwide.

Significance: Moderate, primarily by contributing to mixed worm infections, resulting in decreased feed efficiency.

Effect on Host: The adult stomach worms burrow into the gastric mucosa to suck blood, resulting in haemorrhagic gastritis and anaemia. Young adult worms in gastric glands cause the formation of nodules which further interfere with gastric function, resulting in diarrhoea and dehydration. Low worm burdens frequently occur without signs. Heavy infections cause anaemia, weakness and rapid loss of condition. Extreme thirst and failure to gain weight are results of the diarrhoea.

Diagnostic Information: Eggs of the stomach worm resemble those of Oesophagostomum and Trichostrongylus axei. If necessary, positive identification can be made by culturing eggs in faeces until larvae can be collected, or by postmortem examination of stomach mucosa.

Control: As the larvae are susceptible to drying, frequent removal of faeces and provision of dry quarters are effective control practices. Histotropic stages occur in hyostrongylosis making eradication difficult. Fourth-stage larvae may become embedded in the gastric mucosa. The tissue reacts by surrounding the larvae which results in the formation of nodules. Larvae in the stomach walls of sows are not affected by older drugs. Both IVOMEC® Injection for Pigs and IVOMEC Premix control the adults and the fourth stage larvae of Red stomach worm - Hyostrongylus rubidus. Feeder pigs should be checked and treated appropriately for worms to ensure maximal feed efficiency.

Hyostrongylus adults on wall of stomach		Hyostrongylus adult magnified
(Nodules in stomach wall containing young adult worms) haemorrhagic gastritis		Haemorrhagic gastritis