Trials are described in which the reactions of nine sheep infested with O. columbianum
and three uninfested controls were studied in detail.
The main pathological findings were:-
(i) anorexia, loss in body weight, diarrhoea and increased rectal temperature
followed by subsequent reduced weight gain;
(ii) a decrease in plasma albumin and albumin/globulin ratio and an increase
in plasma gamma globulin particularly after reinfestation;
(iii) eosinophilia commencing three to four weeks after infestation and
(iv) a decrease in packed cell volume, haemoglobin and total plasma protein
concentration, plasma volume, absolute volume of circulating erythrocytes
and total circulating plasma proteins appeared to be dietetic in
Marked macroscopic parasitic lesions with secondary bacterial complications
were observed in all the sheep.
Infestations with comparatively few larvae led to severe disease and even death.