CANINE DISTEMPER

Manawatu Standard, Volume LVI, Issue 200, 14 July 1936, Page 2

CANINE DISTEMPER

IMMUNISING DOGS. EXPERIMENT AT MASSEY COLLEGE. Recently a distemper immunisation experiment was carried out by the Massey Agricultural College, and a. report of the matter has been released lor publication by the North Island Dug trial Association. Tho report states: “For some years past a method of actively immunising dogs against canine distemper has been extensively employed, with a. very high percentage of success, ill Great Britain, Europe and the United States. The method was evolved by Messrs Diinkin and Laidlaw under the auspices of the Field Distemper bund. “The method of immunisation _mvolves establishing a temporary immunity by means of a dead vaccine and then superimposing an active ami lasting immunity by means' of the inoculation of living virus'. Ibis system has not hitherto been available in Australia and New Zealand, owing to the fact that the virus is not particularly stable, at atmospheric temperature, and tho manufacturers to whpm commercial preparation of the mate - al was entrusted were not prepared to place it upon the market until tne> could guarantee its potency. Improvements in their manufacturing technique have now produced a product which remains potent lor a period o three months in cokl storage and 1 J expressed their willingness to snpp y material for ail experimental trial. “The North Island Dog Trial Association found the necessary nnauc and at the end of November last a douhlo fenced compound lo feet by 40 feet was erected to accommodate experimental dogs. As the expert--mental design required all the dogs to run treelv togetner live largo open communal kennels were provided. A small feed House completed the layout. At the beginning of December a number of bitches and tin weaned liters were obtained and placed in tlio compound. After the pups were weaned the bitches were disposed of and tbe pups have been reared ever since witiiin the compound under lock and Kej , 20 pups in all were obtained lor tne experiment. Ten were to be immunised with vaccine-virus, while the it maining 10 were to serve as controls. When immunisation was completed natural cases of distemper were, to be introduced into the compound and suits observed. One small pup died from pneumonia early in J During tho great gale two furtlie pups were killed as a result o Heavy hardwood grating lulling upon them. Otherwise the pups were an perfectly healthy and throve well. INOCULATION PROCESS.

“The supplies of vaccine arrived m mid-J unuu, y and on tne 20tli ot tha,. mouth Id pop® received their lust immunising übso, the remaining seven remaining as controls.. As tar as possible equal numbers ot pups from eacii litter were placed in each group, though there was naturally a preponderance of vaccinated annuals. Un February 18, the inoculated group received their second dose ol vaccine and one week later, on February 4b, this group received tlieir dose oi virus wutcli had been specially shipped in cold storage. 'temperatures luueu alter vaccine and vnus inoculations did not show any reactions. “immunity should have been fully established within ten days of receiving the final dose of'virus, but difficulty was experienced in.obtaining any natural cases ot distemper, and it was not until March 31 that a good case was obtained from Dannevuive. f u.s do 0 was taken into the cum pound and ea<m pup was individually, introduced to urn sick animal and permittee to sniff and lick it. Horn upril r onwards da... temperatures were taken and clinical notes made ol the appearance and symptoms of each dog tinni the expenmeni terminated on May 20. 1“ e incubation period extended some thiee weeks before any. very pronounced symptoms of . ihe disease appealed. iAs weather up to April ‘4O was tine |and%nild, and was men succeeded by a spell ot wet, cold, rough weather. On April 24 all the seven control dogs j were obviously ill with distemper and the first of the group died. rhe vaccinated group ot 10 dogs at tins date were all showing some slight conjunctivitis (inflammation) ol tlie lining I membrane of the eyelids, but were I otherwise perfectly normal save -No. 4, I which showed a slight rise in temperature and some diseliarge irom tile eye. On the 26th the position was generally i unchanged; three of the control group were obviously very ill and another had developed tbe nervous twitcliins iiip~ toms of chorea in the head muscles. The vaccinated group remained normal except tor the. slight conjunctivitis, except No. 4 which had a slightly elevated temperature and other evidence ot ‘slight distemper. , ' On April 30 the second control dog died. On May 4.a third passed away, and oil the oth' of that month the fourth control dog died. By this time the remaining three controls were begrinning to rocover> and at the teimiration of the experiment one had completely recovered, a second was convalescent, whilst the third (with chorea) had recovered except for a slight chorea which it will probably never lose. The vaccinated group which had never been affected save for the slight conjunctivitis, remained fit and increased in weight and tveic in fat condition at the termination of the experiment, save Nos. 4 and 22. No. 4 continued to show evidence of distemper and died ou May 21. For a week previously tho dog had been persistently vomiting after each feed. Post-mortem examination revealed extensive ulceration of the bowel and 429 hook worms were counted. Dog 22 was tliin at the commencement of the experiment ill April. It was repeatedly noticed to have acquired the liabit ot devouring the excrement of its mates, ft never showed any clinical signs of distemper, but became progressively more emaciated and developed a most acute anaemia—-eventually dying on May 17. Autopsy revealed tlie presence of no less than 2780 hook worms in the bowel. . The presence ot worms in this particular dog was obvious for a long time prior to death, but. no attempt was made to treat him lor them as tlie experimental trial was designed to simulate, as tar as possible’, the most unfavourable conditions under which dogs would be kept on any run or station, namely, in cold, , exposed kennels, on foul ground, otl I which they were fed. Such uniavour--1 able conditions arc conducive to dis- , temper in its acutest form, so were deliberately fostered in order to make tho test as exacting as possible.

RESULTS SUMMARISED. “The results may be summarised as follow: — “Ten immunised dogs.—Nine showed no evidence of distemper while one had a mild attack, and eventually succumbed, hut possibly parasitic worms were in part responsible for the unfavourable termination. Quo died from worm infestation. “Seven control dogs.—All contracted .distemper, four died, three recovered—two completely, hut one permanently

affected with slight eho-en, though otherwise apparently normal. “It. must be borne ill mind in appraising the results that no system of biological immunisation has ever yet proved 100 per cent, efficacious, ‘in their final report to the Field Distemper Research Council Dunkin and Laidlaw reported 08,4 per cent, success on 370 dogs. These dogs were foxhounds kept in sanitary and hygienic surroundings. The fact that in'* tlio present trial dogs were deliberately kept throughout under conditions of an extremely insanitary nature and fully exposed to the elements with a minimum of shelter provided a much more exacting test of the efficacy of the methods since all circumstances tended towards lowering their natural resistance to infection. Tn view of’ the results obtained tinder such /exacting conditions 1 am of the considered opinion that the experiment has been a success and that under normally favourable circumstances the doublet vac-cine-virus treatment will afford a verv high degree indeed of immunity against canine distemper in New Zealand ” The report is signed by yj,. j Webster, the veterinarian fl t Massey College. J