284 VETERINARY HYGIENE 



cases of strangles. Such atypical forms have been known to cause 

 outbreaks of typical strangles among young horses; three such 

 outbreaks have been described by Bigoteau.* 



The period of incubation is about 3 to 8 days. The mortality 

 is not high generally, but the type and virulence of the disease 

 vary considerably. Cases are often more malignant and fatalities 

 higher in young foals. Typical cases generally last 2 to 4 weeks 

 and end in recovery. The streptococcus equi is destroyed by sun- 

 light in 8 hours and by desiccation in about 3 weeks (Nocard and 

 Leclainche), while freezing for 2 days does not destroy it (Todd). 



PREVENTIVE MEASURES. Isolation of infected animals and dis- 

 infection of contact materials are the essential methods by which 

 the spread of strangles is prevented in a stud. Sick horses should 

 be removed entirely from the healthy and housed in boxes or else- 

 where away from the main stable. Separate attendants should be 

 provided and feeding utensils, buckets and other stable gear must 

 not be interchangeable. A thorough cleansing and disinfection of 

 stalls vacated by sick horses and the mangers therein must be 

 carried out before other animals make use of them. The opening 

 of abscesses in the common stable or in the yard is a dangerous 

 practice unless straw or other material is used to catch the discharge, 

 which should then be carefully destroyed. If, as is the case in 

 many stables, there is but one attendant whose duties are to nurse 

 the sick and prepare the food for the healthy and feed them, he 

 must be instructed to attend to the sick animals when his other work 

 is done and on no account to omit to wash his hands and his 

 boots after fomenting an abscess or grooming a sick horse. Over- 

 alls should be provided for use when tending sick horses. The 

 stableman is undoubtedly the chief intermediate carrier of strangles 

 infection. Horses which have recovered from strangles should not 

 be allowed to mix with the other horses in the stable for 3 or 

 4 weeks after they have returned to work. Horses which have so 

 far advanced in convalescence as to be put to light work are not 

 necessarily free from infection. All new purchases, and especially 

 young horses, should be quarantined for at least 15 days before 

 being brought into contact with other animals. Cases of " catarrh " 

 should be isolated until some time after the symptoms have sub- 

 sided. If a common water-trough is made use of it is advisable 

 to close it temporarily. Under no circumstances should strange 

 horses be allowed to drink from a stable yard-trough. 



One attack confers a certain degree of immunity. This, how- 

 ever, is in some cases insufficient to prevent further reappearance 

 * Journ. Comp. Path., 1893, Trans., Vol. VI. 



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