Investigations into the Nature, Causation, and Prevention of Texas or Southern Cattle Fever Page: 105
301 p. : ill. (some col.) ; 24 cm.View a full description of this book.
Extracted Text
The following text was automatically extracted from the image on this page using optical character recognition software:
TRANSMISSION OF TEXAS FEVER.
with this fact fairly well determined the true explanation that the
young ticks were directly responsible for the disease seemed too far-
fetched to deserve attention until it was demonstrated in the following
manner. A yearling heifer (No. 138) had been placed in a box stall
and a number of young ticks, hatched artificially in glass dishes, had
been placed on this animal at intervals, beginning August 14, in order
to determine whether ticks in the capacity of blood-sucking parasites
made any impression on the number of blood corpuscles. It was found
by a periodical estimation of the number of red corpuscles that after a
certain time this number fell so quickly and so markedly as to be
wholly incommensurate with the small amount of blood abstracted by
the ticks. At the same time other symptoms of Texas fever appeared
and the parasite was detected in the blood.
The experiment was repeated on several other animals as soon as
young ticks could be obtained.
No. 140 (heifer, 2 years old) kept in a box stall on a neighboring farm. The
young ticks 3 to 4 days old were placed on it September 9. It was found dead Octo-
ber 2. Both blood examination during life and the autopsy demonstrated Texas fever.
No. 137 (heifer, 1 year old) was placed in field X, a wooded lot to which no in-
fected cattle had been admitted, and on September 9 young ticks were placed on it.
It passed through a severe attack of Texas fever and was killed in a dying condi-
tion November 6.
No. 144 (cow, 8 years old) was also kept in field X. The young ticks were placed
on it September 17 and it was found dead October 3. In this case also the nature of
the disease was beyond question.*
Experiment 13 (production of Texas fever in the winter season by
placing young ticks on cattle kept in an artificially-heated stable).-The
result of experiment 12 was so important that it was deemed best to
repeat it in an artificially-heated stable, as the season was too far
advanced for ticks to thrive in the open air. The stable was warmed
by means of a coal stove. The temperature fluctuated between 650 and
800 F. A complete history of all the cases experimented on in this
way is given in the appendix.
The following animals were exposed and infected with young ticks:
No. Age, etc. Placed in Infection with Number of infections. Result.
No. ge, etc. stable, ticks.
143 Heifer, 1 years... Oct. 27, 1890 Oct. 28-Nov. 8 2 (200-300 each time). Slight, if any effect.
145 ....do .......... .. ..do . ..... Nov. 21-Dec. 3 7 (200-300 each time). Prolonged case of Texas
fever. Recovered
Mar. 18, 1891.
149 ....do ................do ....... Oct. 28-Nov. 21 6 (15 each time) .... Slight, if any effect.
117' Southern heifer, 2 Nov. 19, 1890 Nov. 21- Dec. 3 7 (200-300 each time) . Do.
years.
130 Cow, 2 years ...... Dec. 12, 1890 Dec. 13-Dec. 29 9 (200-300 each time). Marked case of Texas
fever. Recovered
Feb. 18, 1891.
152 Cow, 4j years...- .o ..............do ........... 9 (200-300 each time). Mild case of Texas
fe ve r. Recovered
Jan. 20, 1891.
SIn stall with No. 145.
The young ticks placed on Nos. 117, 143, 145, and 149 were descended from adults picked from dis-
eased natives (Nos. 137, 138, and 140). Those placed on Nos. 130 and 152 were descended from adults
received directly from North Carolina.
* For fulldetails concerning the ticks and the course of the disease in these cases
see appendix.105
Upcoming Pages
Here’s what’s next.
Search Inside
This book can be searched. Note: Results may vary based on the legibility of text within the document.
Tools / Downloads
Get a copy of this page or view the extracted text.
Citing and Sharing
Basic information for referencing this web page. We also provide extended guidance on usage rights, references, copying or embedding.
Reference the current page of this Book.
Smith, Theobold & Kilborne, Fred Lucius. Investigations into the Nature, Causation, and Prevention of Texas or Southern Cattle Fever, book, 1893; Washington D.C.. (https://texashistory.unt.edu/ark:/67531/metapth143538/m1/105/: accessed July 16, 2024), University of North Texas Libraries, The Portal to Texas History, https://texashistory.unt.edu; crediting University of Texas Health Science Center Libraries.