496 



TELOSPORIDIA 



Development in the Tick. — When an adult tick or a nympli bites a dog 



and takes in blood containing the oval parasites already described, these 

 parasites develop in the gut into round or oval bodies, 4 to 5 in diameter, 

 the chromatin remaining undisturbed . 



The cytoplasm now partially divides into a portion with and a portion 

 without chromatin, the latter turning round to form a tail to the former, 

 thus constituting a club-shaped body, which gradually becomes an ookinete. 



In the adult these wander into the ova, while in the nymph they simply pass 

 into the embryonic tissue. 



In either case they become rounded, and form the zygote, which breaks 

 up into sporoblasts, and these, again, into sporozoites, which infect the salivary 

 glands of the nymph and the adult of the second generation. This development 

 explains Loundsbury's experiments. 



Pathogenicity. — The pathological eftects are divided by Nocard and Le- 

 clainche into two types — the acute, always fatal, and the subacute, ending in 

 recovery. 



Acute Form. — In the severe attack the dog quickly becomes ill with high 

 fever (40° C), accompanied with great weakness. After the attack of fever 

 comes a stage of subnormal temperatures. The mucous membrane becomes 

 pallid, bluish, or icteric. Respiration is laboured, and the movements of the 

 animal are shaky. Vomiting is frequent. The spleen is enlarged, the urine 

 albuminous, and in 3-5 per cent, of cases there is haemoglobinuria. The blood 

 is pale and watery, and the serum stained with haemoglobin or bile pigments ; 

 the red corpuscles are reduced (in one dog, according to Wright, from 

 5,800,000 to 1,000,000) and altered, some becoming larger, others smaller, 

 than normal, and often nucleated. The haemoglobin is diminished, the 

 smallest amount observed being 17 per cent. Usually the leucocytes are 

 increased up to even 60,000, but in some cases they are reduced. Poly- 

 morphonuclear and mononuclear leucocytes share the general increase. 

 Phagocytosis is not energetic, being rarely met with. The animal dies in 

 from three to six days. 



Subacute Form. — This is characterized by progressive anaemia and feeble- 

 ness, with sometimes a little haemoglobinuria or a little icterus. Fever may 

 at first be high, but generally falls to normal. The anaemia is very pro- 

 nounced, and is accompanied with paralysis, etc. 



The attack lasts six weeks, and the convalescence takes three months. 



Post-Mortem Appearances. — The mucous membranes are pale, and there is 

 icteric staining of the tissues. Congestion and enlargement of the spleen, 

 more rarely of the liver, oedema of the lungs, congestion of the kidneys, 

 and inflammation of the stomach and intestines may be noted, but some- 

 times no macroscopical lesions are to be seen. 



Histological. — The capillaries of the alveoli are dilated, and their walls 

 show some proliferation of the cells, and there may be leucocytes and red 

 corpuscles in the lumen of the air cell. 



In the heart the capillaries are dilated, and there may be slight haemorrhages. 

 There is no change in the skeletal muscles. The liver has the central vein 

 and the interlobular capillaries much dilated, as are the intralobular vessels. 

 The fibrous tissue is normal, but the Uver cells are distorted, and in many 

 cases destroyed. The spleen contains a large quantity of blood in its pulp. 

 The kidneys only show dilatation of the bloodvessels, especially those of the 

 glomeruli. The suprarenal capsules have all the capillaries (cortex and 

 medulla) dilated, as has the pancreas. In the brain and spinal cord there is 

 only slight dilatation of the capillaries, and slight excess of cerebro-spinal 

 fluid. In the small intestine the vessels of the villi are congested and crowded 

 with infected corpuscles, as are those of the mesentery and omentum. The 

 lymphatic glands are normal, except dilatation of their smaller vessels. The 

 general histological condition is engorgement of the organs by dilatation of the 

 capillaries. 



Treatment. — Quinine, benzoate of soda, calomel, etc., have all been advised. 

 Nuttall and Hadwen have introduced Trypanbleu treatment with success. 



