70 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 1 



Professor Lounsbury commenced the study of ticks in 1898. He 

 first determined that heartwater,*^ a disease in that country of sheep, 

 goats and cattle, which often proves fatal, is transmitted by the Bont 

 Tick, Amhlyomma hehraeum. The stimulus from this discovery has 

 resulted in the determination that several diseases of animals in South 

 Africa, besides red water or Texas fever, are thus transmitted, includ- 

 ing malignant jaundice of dogs, African coast fever of cattle, and 

 biliary fever of horses, mules and donkeys. Not only has it been 

 demonstrated that these diseases are transmitted by ticks, but the 

 species and the stages of each that are carriers of the pathogenic 

 organisms have been determined. 



The cattle tick of this country, Margaropus {=Boophiliis) annulatus, 

 now known as the North American Fever Tick, and its varieties found 

 in other countries, all transmit Piroplasma higeminum. In Europe, 

 however, the European Castor Bean Tick, Ixodes ricinus, a species also 

 found in this country, has been found to transmit the disease, imbibing 

 the infection as an adult and transmitting it in the larval and nymphal 

 stages following. As is generally known, the larva of the North 

 American Fever Tick transmits the disease to susceptible animals when 

 the previous generation has imbibed the infection, thus passing through 

 the egg. 



Lounsbury has found that in heartwater but one species, Amhly- 

 omma hehraeum, the Bont Tick, is concerned; as a larva it feeds on 

 an infested animal, transmitting the disease in both nymphal and 

 adult stages to a susceptible animal. The infection does not pass 

 through the egg as with splenetic fever. 



Malignant jaundice was found by Lounsbury to be transmitted 

 from one dog to another by the Dog Tick, Haemaphysalis leachi. 

 The infection is not transmitted by the larva or nymph, but by the 

 adult alone and only when the adult of the preceding generation 

 imbibed infectious blood. Ten was the smallest number of ticks that 

 produced the disease in Lounsbury 's experiments, although he con- 

 cludes that a single pathogenic tick is probably ample to communicate 

 infection that may lead to death. Christophers has found this dis- 

 ease in Madras, India, to be transmitted by Rhipicephalus sanguineus, 

 and has followed the life cycle of the parasite, Piroplasma canis. 

 Daniels and Stanton state that Dermacentor reticulatu^ transmits 

 the disease in Europe, but I have not seen such record. 



African coast fever, an extremely fatal disease of cattle in South 



cin Cape Colony whole strips of country have become almost useless for 

 sheep and goat breeding, as have certain districts in the Transvaal, due to 

 heartwater. 



