144 Journal of the IDEPARTMENt of Agriculture. 



may no longer he present. The first outbreaks of East Coast fever on 

 a farm are also very frequently mistaken for g-all-sickness. Although 

 gall-sickness resembles in many respects the redwater under discussion, 

 it is a definite disease caused by a micro-organism. In the blood 

 corpuscles of sick animals small chromatic dots are found, ^luated 

 usually on the margin which are interpreted by us to be of parasitic 

 origin and were called Anaplnsnui viai-fjinaJe ; the scientific name for 

 the disease would then be anaphismosis. The maiii dilference 

 between anaplasmosis and redwatei is the absence of red urine in the 

 former, otherwise it resembles it in many details, and the two diseases 

 are frequently maintained by farmers to be siste]- diseases. It has 

 been experimentally transmitted by blue ticks (tho same batch of ticks 

 were capable of tiansmitting both redwater and gall-sickness), but 

 there are otlier ticks also responsible, probably some or all of the genus 

 IJhipicephalus, which includes the brown and red ticks. At least the 

 black-pitted tick lias transmitted the disease in experiments. Wlien 

 the tides are infected, both with redwater and gall-sickness, the 

 organism of redwater appears first, the incubation peiiod being about 

 seventeen to twenty-one days ; gall-sickness, with a long incubative 

 period, from sixty to eigdity days, appears later. Eecovery from gaJl- 

 sickness does not protect against redwater or .ice versa. This fact 

 proves the non-identity of the two diseases. As in the case of red- 

 water in cattle or biliary fever in horses, i lie animal which has 

 recovered from the disease retains the infection in the blood, and such 

 blood wlien injected into susceptible cattle produces the disease. The 

 progeny of ticks which drop off immune cattle also propagate the 

 disease; in this way a farm l)ecomes permanently infected. The 

 young calves, suffering less from the disease than adults, " salt " in 

 iliQ Dreatest number of cases. 



Fevers caushd by Gonderia mutatis (eokmehly Fiioplasina niutans). 



Cattle born on the veld of South Africa sometimes show in their 

 blood a small parasite in the red corpuscles lieionging to the Piro- 

 plasnui gTOup. The scientific name is now Gonderia 7nutans (pre- 

 viously Piyoplasma iinifans). Morphologically it. so mi;ch resembies 

 the East Coast fever parasite that its identification in a blood-smear 

 occasionally causes difhculties. When a susceptible animal becomes 

 freshly infected with this parasite it will show a slight irregular fever 

 of varying duration and aiaaemia may become markedly pronounced, 

 and symptoins of illness with loss of appetite and condition may show 

 themselves during its course. Death is only rarely noted. The 

 disease was experimentally transmitted by means of red and brown 

 ticks. It appeared after a jjrolonged incubation period lasting fiom 

 twenty to fifty days. Similarly to what is known in redwater and 

 gall-sickness, the parasite is present in the blood of a recovered animal, 

 but contrary to the former diseases it can be found microscopically m 

 quite a number of cases long after recovery. This parasite may 

 reappear in considerable numbers when an animal is suffering from 

 an inter-current disease and so mask the original ailment. The 

 disease caused by Gonderia tnutans may conveniently be called the 

 " benign " or " mild form " of gall-sickness. 



Fevers caused by Spirociiaetes (SpiiocJiacta tJicileri). 



Spirochaetes are blood parasites in the shape of small cnrves, 

 looking like a corkscrew, swimming in between the red corpuscles of 



