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PARASITOS Y ENFERMEDADES PARASITARIAS
DE LOS ANIMALES DOMESTICOS


Dictyocaulus in horses,donkeys and sheep

Dictyocaulus arnfieldi

This nematode is seen in the trachea and bronchi of horses and donkeys. It appears to be is a relatively benign infection in donkeys since it is rarely associated with clinically obvious disease. In horses,  because the worm  rarely reaches maturity, infections are usually not patent.

Life cycle - the life cycle is similar to D. viviparus except for the following:

  • The stage passed in feces  is an egg containing an L1 which hatches soon after leaving the host.

  • The prepatent period ranges from 2 to 4 months.Patent infections may be seen in donkeys of all ages but in horses are usually only seen in foals and yearlings.

Pathogenesis - The lung lesions seen in both horses and donkeys consists of raised areas in the caudal lobes each of which contain lungworms inside a small bronchus and a mucopurulent exudate. The bronchial epithelium is usually hyperplastic, has an increased number of mucus cells and is infiltrated with lymphocytes.

Clinical signs - Infections in donkeys may produce mild clinical signs of harsh lung sounds on auscultation and a slight increase in respiratory rate. In horses clinical signs are uncommon in foals and yearlings and in adult horses may be present as a persistent cough and increased respiratory rate.

Epidemiology - It is believed that horses acquire their infections from pastures contaminated by  donkeys with patent infections. Donkeys are usually infected first as foals and through re-exposure remain infected throughout their lives.

Diagnosis - First stage larvae are easily recovered from feces of infected donkeys. These larvae are similar to the L1s of D. viviparus but are slightly larger and have a sharply pointed tail.


    

 

Parásitos y enfermedades parasitarias de los animales domésticos
Dr. Colin Johnstone (autor principal)
Derechos de copia © Universidad de Pennsylvania