Changes

The eggs are small and oval with a thin shell, they will often hatch in the large intestine so L1 larvae are expelled in the hosts faeces.

The eggs are small and oval with a thin shell, they will often hatch in the large intestine so L1 larvae are expelled in the hosts faeces.

==== Life-Cycle ====

==== Life-Cycle ====

''S. westeri'' has a typical [[:Category:Rhabditoidea|strongyloides]] life cycle, with both a free living and parasitic cycle. The free living cycle involves male and female worms reproducing sexually on the ground, this can occur for several generation with no parasitism taking place. The parasitic phase involves only female worms and occurs from ingesion of L£ larvae or their penetration through the hosts skin. Infection my also be transmissed vertically from the dam to the foal by larval migration to the mammary tissue and ingestion by the foal with the dams milk. Once in the host the larvae migrate to the small intestine where they tunnel into the epithelium at the base of the villi and moult to L4 and then adult females. Females produce eggs without sexual interaction that can develop to become both male and female larvae. The pre patent period is between 1 and 2 weeks dependant on the level of infection.

''S. westeri'' has a typical [[:Category:Rhabditoidea|strongyloides]] life cycle, with both a free living and parasitic cycle. The free living cycle involves male and female worms reproducing sexually on the ground, this can occur for several generation with no parasitism taking place. The parasitic phase involves only female worms and occurs from ingesion of L3 larvae or their penetration through the hosts skin. Infection my also be transmissed vertically from the dam to the foal by larval migration to the mammary tissue and ingestion by the foal with the dams milk. Once in the host the larvae migrate to the small intestine where they tunnel into the epithelium at the base of the villi and moult to L4 and then adult females. Females produce eggs without sexual interaction that can develop to become both male and female larvae. The pre patent period is between 1 and 2 weeks dependant on the level of infection.

 

==== Pathogenicity ====

==== Pathogenicity ====

Pathology is rarely seen in adult horses due to the development of immunity, though penetration of the skin by larvae may still cause irritation anddermatitis. Adults with larvae in beneath the skin and in the abdomen can act as carriers. In foals heavy infections can cause severe enteritis and diarrhoea. It should be noted that apparently healthy animals can still have high faecal egg counts.

Pathology is rarely seen in adult horses due to the development of immunity, though penetration of the skin by larvae may still cause irritation anddermatitis. Adults with larvae in beneath the skin and in the abdomen can act as carriers. In foals heavy infections can cause severe enteritis and diarrhoea. It should be noted that apparently healthy animals can still have high faecal egg counts.