2i 



Report of the Dept. of Agriculture, Nairobi, Britiali E. Africa, 

 1911-12. 



Tsetse-Flies. — Mr. C. A. IS'eave, the Chief Stock Inspector, 

 reports that Glossina longipennis was the only species found iu 

 the country south of Marsabit. Though very troublesome, this 

 ily does little damage to horses, mules, cattle, sheep or dogs, but 

 trypanosomiasis iu camels is frequent. The fly is prevalent, 

 especially during* the rains, around Marsabit, outside the forest 

 and along the whole road to Uaso Nj'iro. 



Ticks. — Ainblyomvia variegatum and .4. hehraeum are the 

 most common species about Marsabit. They cause serious 

 abscesses and those produced by the latter species are so large, 

 hard and fibrous peripherally that they have to be dissected out. 

 The lesions caused b}^ the ticks afford entrance to the infection of 

 epizootic and ulcerative lymphangitis. Haemaphysalis leaclii 

 is common on all dogs ; Rhipicepliahis evertsi about the anus of 

 horses and cattle; R. simus, R. decoloratus and R. appendi- 

 culatus on horses and cattle. The acting chief veterinary 

 officer at Nairobi reports that an appendiculatiis which 

 feeds as a larva on a sick animal is known to be 

 capable of transmitting East Coast fever as a nymph ; whether 

 it can do so as an adult is uncertain and experiments have not 

 been made, but there is no reason for supposing that it will behave 

 differently from the same species in S. Africa. Experiments with 

 R. evertsi, ''the red-legged tick," have failed, and even in 

 S. Africa, though often attempted, positive transmission is seldom 

 effected. Attempts to get R. pulchellus , the common " yellow- 

 backed tick," to feed upon cattle or other large animals, in the 

 larval state, have failed, and though it will probably prove to be a 

 carrier of East Coast fever, great difficulty has been experienced 

 in obtaining natural cases of the disease in an infected area near 

 the Athi River, where this tick abounds. Adult cattle in the most 

 densely stocked districts in E. Africa, viz. Kavirondo, Ivisii, 

 Nandi, parts of Lumbwa and Sotik, and Mesu and Nyeri Kikuyu, 

 as well as portions of Nairobi Kikuyu and Machakos appear to 

 be immune or practically immune from East Coast fever. It has 

 been shown that this is due to the recovery of the young animals 

 and that those which reach maturity without contracting the 

 disease succumb almost as readily as do grade stock. It would 

 thus appear that either the young cattle possess a resistance to the 

 disease which is lost later in life, or that the type prevailing in the 

 districts referred to is milder than elsewhere. The resistance of 

 newly born calves to local strains of the disease was tested and the 

 mortality was high. Similar experiments with material of S. 

 African origin resulted in the recovery of 6 out of 15, three of 

 them half-breds ; among those that died two were pure bred. 



Identity of East Coast Fever in East and South Africa. — Three 

 animals known to have suffered from East Coast fever and 

 released as immune and two others believed to be susceptible were 

 exposed to the attack of infected ticks received from Pretoria, 

 equal numbers being placed on each of the five animals. The two 

 beasts regarded as susceptible died; the other three did not show 



(28536—2.) Wt. P 2601. 2000. 2/13. D & S. 



