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Scott (J, W.). Swamp Fever in Wyoming. Economic Importance, 

 General Cliaracteristics and Control. — Wyoming Agric.Expt. Sta., 

 Laramie, Bull. no. 121, June 1919, 51 pp., 14 plates, 7 figs. 



The history, seasonal occurrence and distribution, as well as- symp- 

 toms, methods of diagnosis and types of this disease of horses are fully 

 discussed. 



Great difference of opinion exists with regard to the mode of trans- 

 mission, but experiments prove that bitmg flies, of which Stomoxys 

 calcitrans and Tahanus are specially mentioned, are responsible for 

 the majority of infections, although they may not be the sole trans- 

 mitting agents. The disease is most prevalent in August and Septem- 

 ber, a season when these flies are most abundant in Wyoming. No 

 exact figures of the losses incurred are available, but the author 

 believes that not less than 2,000 horses have died of this disease in 

 Wyoming in the last 25 years. 



Since the virus of swamp fever has not been discovered and its 

 natural habitat is unknown, no measures of control can be aimed 

 directly at the parasite producing the disease. It has also been found 

 impossible to produce immunity, and, while the symptoms may in 

 some cases be alleviated by the use of certain drugs, no treatment 

 has given more than temporary benefit. Some of the more notable 

 suggestions made by different authors for the control of swamp fever 

 are reviewed. These show a rather close agreement on recommenda- 

 tions of a general nature, differences being due to local conditions or 

 individual opinions regarding the transmission of the disease. From 

 personal observations in Wyoming and in view of suggestions pre- 

 viously made, the author has reached the following conclusions with 

 regard to remedial measures. The diagnosis of suspected cases should 

 at once be entrusted to the State Veterinarian, and all horses suffering 

 from the disease should be immediately killed or isolated. Owing to 

 the fact that the virus can withstand heat, drought, cold and putre- 

 faction, the carcases of all horses that are killed or die of the disease 

 should be burned or buried deeply. If affected horses are not imme- 

 diately killed they should be segregated, all healthy ones being removed 

 to a new, dry pasture at sufl&cient distance to prevent the passage of 

 biting flies. The continued isolation of chronic cases is essential. 

 The incubation period being two to four weeks or longer, a careful 

 watch must be kept over all horses that have been exposed to infection ; 

 their temperatures should be taken once a day and if any symptoms 

 of the disease appear they should be isolated for further observation. 



The most difficult problem m the control of swamp fever is the 

 detection of the chronic and apparently healthy carrier. Japanese 

 authorities recommend that recovered cases that can pass the exercise 

 test wdthout showing any symptom of the disease should be set free. 

 But if the blood is still virulent this plan is not safe ; it has been proved 

 that a severe case may arise from a very mild one. Wet, badly 

 drained or swampy pastures should be avoided. A pure water supply 

 should be obtained either from springs or from open running streams. 

 It is advisable to suspend all movements of horses from a swamp 

 fever area during, and somewhat beyond the infective season, from July 

 to December, and quarantine regulations should be enforced to this 

 effect. Disinfection of stables and of the excreta has been strongly 



(C610) VVt.1921/144. 1,500. 11.19. B.&F.Ltd. Gp.11/3. A 



