Diagnosis. The diagnosis may easily be made by a microscopic examination of the urine to determine the presence of the egg.
Prognosis, etc. The severity of the disease varies directly with the number of parasites (and hence the number of eggs) in the body. Fortunately, in the majority of cases, the number of parasites is small, though it may increase from repeated infections to 500 or more. In cases of comparatively light infection the disease is reduced to a slight chronic cystitis, with now and then exacerbations, in course of which a slight amount of blood and pus is passed in the urine. The disease may last for years without apparent increase. In the most severe cases death may occur from various causes, rupture of the bladder, ascending pyelo-nephritis, uræmia, albuminuria; the patient may die in marasmus, being exhausted by the dysentery or the anæmia.
Bilharziosis is accordingly not such a fatal disease as has sometimes been supposed.
HEAT STROKE—OVER-EXERTION.
In oxen and sheep heat stroke is rare as a primary accident, but it is frequently produced by over-exertion resulting from the combined action of the sun’s rays, heat, and fatigue due to work or travelling.
It is commonest during the hottest months of the year in oxen doing hard work or in flocks which have been travelled considerable distances. It may also be seen during cooler seasons as the result of exceptional fatigue.
The disease results from a general intoxication which reacts most markedly on the cerebro-spinal centres. It is in fact a complex intoxication resulting from failure of the natural excretory organs to perform their function completely, and from excessive central heat acting on the nervous centres.
Fat animals out of condition are more readily attacked than working animals or sheep reared in the open air.
The symptoms are very characteristic. Oxen when attacked first of all show extremely rapid respiration and dyspnœa, announcing progressive asphyxia. They move with the nostrils dilated, the eyes prominent and injected, the mouth open and the tongue lolling out. Then all of a sudden they come to a stop beside a wall, or, if at liberty, in a ditch, and refuse to move. They may die rapidly with symptoms of asphyxia if they are forced to move until completely exhausted. In others, after a rest of several hours, the breathing becomes slower, the anxiety less and normal conditions return.
In sheep the same general signs may be seen: panting respiration, cyanosed mucous membranes and extreme anxiety, while death follows rapidly in the same way, with symptoms of asphyxia.