Report on protective inoculation against tick fever : an account of an experimental inquiry into its effect on cattle, and on meat and milk, together with some notes on protective measures other than inoculation / by FrankTidswell.

Tidswell, Frank, 1867-1941.

Date:: 1899

Credit: Report on protective inoculation against tick fever : an account of an experimental inquiry into its effect on cattle, and on meat and milk, together with some notes on protective measures other than inoculation / by FrankTidswell. Source: Wellcome Collection.

Provider: This material has been provided by Royal College of Physicians, London. The original may be consulted at Royal College of Physicians, London.

13/20 (page 9)

$Taking the first decided drop in the number as a guide, the decrease commenced between 7 and 14- days after inoculation, as a rule on tbe 10th or 11th daj^ Its full extent was reached between 12 and 23 days, usually by the 17th day. Prom this onward, recovery ensued, and the numbers became normal again at various times between the 23rd and 90th days. In the majority (10 of the 12 animals), the numbers were practically normal in a month after inoculation, but in the other two the time taken was 10 and 13 weeks respectively. These results are in accord with the statements of Smith and Kilbourne, who found that in Texas Fever the senemia did not last longer than 3 or 4 months, and was usually recovered from in a much shorter time. (1, p. 42.) The loss amounted to between | and ^ the normal number of corpuscles, and was therefore milder than in natural tick fevep, in which it amounted to between ^ and f of the normal. (1, p. 39.) Other effects in tlie blood, such as changes of the form of the red corpuscles and leucocytes, and the presence of the micro-organisms, were observed by us; but as their description would unduly burden this report without serving any useful purpose, their consideration is held over for future separate communication. 3. Changes in the urine, especially “redwater” luemoglobinuria, form the third important feature of Tick Fever. Eedwatcr is not of constant occurrence in natural Tick Fever. It has been observed after inoculation, but was not found in any of our animals, although the urine was subjected to spectroscopic scrutiny in order to detect the faintest indications of it. Chemical analyses of the urine showed the presence of an abnormal constituent (albumin) in 7 of the 11 cases in which it was examined. It was not great in amount, and soon disappeared as a rule, although in one case it persisted for 52 days. Its appearance indicates interference with the function of the kidneys, but this did not seem to amount to actual disease, since the variations in quantity, specific gravity, urea, &c., were not not greater than in healthy animals. Neither jaundice, nor any other symptom indicative of liver disturbance, was observed by us. («) The inoculation illness does not last longer than a month or six iceeks as a. rule. The duration of the inoculation illness is shown by the statements in the following table as made up of the three periods of incubation, reaction, and convalescence. Table V.—Showing duration of inoculation illness. Cow. Blood. Incubation. Reaction. Conialesccnce. Total duration of illness. (lays. daj's. days. days. I ft 6 10 14 30 II A 10 4 so 100 Ill A 0 4 47 OO IV 15 7 7 SO 50 V B s <) :ii .50 VI B 11 (i 15 32 VII C 10 10 12 32 VIII K I 10 1!) 33 IX D <) 7 killed. X E t 7 18 32 XI E“ 7 8 12 27 XII F s (5 9 23 XIII Et 7 0 11 23 * Injected in cli\ ided doses (10) of 1 cc. each. j- Injected intravenously. The periods of incubation, during which the animal is becoming sick, and reaction, during which it is more or less acutely sick, have already been siifEciently commented upon. The two together extend up to the time of subsidence of the fever. But recovery did not immediately follow on this stage. Certain disease ]irocesses still went on, and were revealed by the conditions observed in the blood and urine. Nevertheless the general tendency was towards recovery, and this after-period Avas one of convalescence, ending with a return to the normal. It will be seen that the period of convalescence varied from 9 to 86 days, but it was completed in the. majority of the animals (8 of the 12*) in less than 3 weeks. The total duration of the illness, as reckoned from the time of inoculation to the end of convales- cence, varied from 23 to 100 days, but was usually not longer than about a month (33 days or less in 8 of the 12). We did not observe relapses, debility, nor any of the other scquehc mentioned by Smith and Kilbourne as following on natural Tick Fever (1 p. 22). Convalescence was not more interrupted tban in other diseases, and the normal when reached appeared to be well maintained. It is obvious, however, that remote effects, if there be any such, have not yet had time to appear. In view of the well-knoivn healthy appearance of the southern animals in America, and the statements of authors tliat recovery from Tick Fever is usually complete, it is not expected that any further conse(|ueiices of inoculation will be observed in the animals kept under observation. (c) The Effect of Inoculation on Meat and 3Iilk. (1.) Dleat.—No direct experiments were performed to ascertain the effect of inoculation on meat. The satisfactory determination of the nutritive value of a food-stuff necessitates prolonged and intricate physiological observations. No results important enough to justify the time and labour involved could have been obtained in the period covered by the experiments. Consequently, reliance was placed on the indirect method of determining the effect on the meat by inference from the effect on the general health and condition of the animal. This method is the one usually adopted in such cases, and is sufficiently accurate for practical purposes. It should be mentioned that we had an opportunity of examining the meat of the animal slaughtered during the period of reaction. AVe ;!75it4—15 * Uno animal, No. IX, wa*^ slamrlitcrcil duriiif;’ the period ol reaction.$