762 Piroplasmoses. 



body of the mammals either by tlie larvae nymphs (Texas 

 fever), or by the sexually ripe ticks (piroplasmosis of sheep 

 and dogs). Other piroplasma do not pass through the eggs, 

 but are transmitted only by the nymphs, which have sucked 

 the infected blood as larvae, or by matured ticks, which sucked 

 it as nymphs (tropical piroplasmosis, piroplasmosis of horses). 

 With -a few exceptions, a species of ticks transmits only 

 a certain species of piroplasma, while one certain piroplasma 

 may be transmitted in different localities by different kinds of 

 ticks. 



The ticks are arthropodes, which as Ixodinae and Argasidae form 

 the family of Ixodidae. As transmitters of the piroplasma: the Ixodinae 

 come exclusively into consideration, while ticks of the genus Argas 

 transmit the infection in spirochetoses. 



The Ixodinae are obligatory parasites and exist on blood which 

 they suck from mammals by pricking the skin with the proboscis, more 

 correctly with the hypostome. The females impregnated on the hosts 

 fall to the ground, where they lay eggs on blades of grass. The hatched 

 larvae look for a host in order to suck blood; in some species they 

 then develop on the same animal up to the nymph stage or also to 

 sexual maturity, while in others the larvae as well as the nymphs, or the 

 nymphs alone, leave the host, in order to develop into the next stage. 

 According to the nature of the development the Ixodidae may be 

 combined into the following groups (Meuleman) : 



1. Species which pass through their development on the same host; here 

 belong the species of the Boophilus (Margaropus, Ehipicephalus, blue ticks), namely 

 B. annulatus, B. decoloratus, B. australis and B. argentinus (according to Neumann 

 only varieties of one species); all are transmitters of Texas fever; the B. decolor- 

 atus transmits also tropical piroplasmosis. 



2. Species which leave the host as nymphs; here belong Ehipicephalus 

 evertsi (red tick: transmitter of East African coast fever, and the piroplasmosis 

 of horses), Eh. bursa (transmitter of piroplasmosis of sheep), and Hyalomma 

 aegyptium (transmitter of Texas fever?). 



3. Species which leave host as larvae and as nypmhs; here belong Ixodes 

 ricinus s. reduvius (transmitter of piroplasmosis of cattle in Europe, probably also 

 of piroplasmosis of dogs), Ehipicephalus appendiculatus (brown tick), Eh. nitens, 

 Eh. simus (dotted black tick), and Eh. capensis (transmitter of coast fever). Eh. 

 sanguineus and Haemaphysalis leachi (transmitter of piroplasmosis of dogs). 



Pathogenesis. Some piroplasma, as for instance, the 

 ordinary piroplasma of cattle (Texas fever), of dogs, and of 

 sheep, exert their pathogenic action by penetrating the red 

 blood corpuscles and causing their destruction. According to 

 the intensity of the affection a larger or smaller number of 

 red cells is destroyed, as a result of which a more or less pro- 

 nounced anemia develops, and simultaneously the hemoglobin 

 of the attacked cells is eliminated into the blood plasma. If 

 only a small number of erythrocytes is destroyed, only a hemo- 

 globinemia results, the eliminated hemoglobin is then changed 

 in the liver into bilirubin, and eliminated as such, while in 

 a greater destruction of blood corpuscles a part of the hemo- 

 globin is passed with the urine, and icterus sets in at the same 



