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Studies in the Epizootiology of Avian Tuberculosis
36
THE VETERINARY J OURNAL
STUDIES IN THE EPIZOOTIOLOGY OF AVIAN TUBERCULOSIS. By D . C . MATHhSON, F .R.C.V.S., D.V.S . M(V ict. ). From the Department of P athology , Bacteriology and Meat Inspection, The Royal (Dick) Veterinary College, Edinburgh. DURING the past six years the writer has had under observation for a period of twelve months each, six high-grade flocks consisting of from four hundred t o six hundred pullets, drawn from various parts of Great Britain ; housed under first class conditions; scientifically fed; and controlled by skilled management. The birds came under observation in October of one year and remained under observation till September of the following year. Each bird was carefully examined (Matheson, 1) before being allowed to enter the flock; any bird not in apparently good health was rejected. The comparatively small number in the first flock was due t o the rigorous eliminating examination, which , h owever, was justified subsequently by the improved type of bird that was presented for acceptance. The birds were arranged in groups of six, each group ha ving a separate pen and a separate grass run, providing ample accommodation . The breeds represented included: White Leghorn, White Wyandotte, Rhode Island R ed, Ancona, Black Leghorn, Light Sussex, Buff Rock, Barnevelder, Black Minorca, Exchequer Leghorn, Barred Rock, Cuckoo Leghorn.
N~
/926 / 9 27 1928
/9 2 4
/ 9 25
1925
1926 / 9 27 / 9 2 8
/929
1929
/930
7
/
6
5 4
_
r-..
/:/r'
3
2
./n -
r-.. _
'-'~
K'.x:(
/'
r-..
/ .I V V-- ./
/r'
/
-
~
/
/
-
-
..r{/
......,
......,
0 Dc.M
FiG N'? / 0- - - ~
=
otlt6reoks
•
•
=
cases
STUDIES IN EPIZOOTIOLOGY
37
Every bird dying during the period of observation was submitted to post-mortem examination in the writer 's laboratory. Tuberculosis was one of the first disease to make its appearance. Fig. No. 1 shows the number of outbreaks and the number of cases which occurred in each of the years under observation . It will be noticed tha t it was not until the last two years that more than one case occ urred in one pen. The sharp rise in the number of cases in the period 1929-1930 was due to the fact that in one pen several birds were affec ted. The actual number of outbreaks was, however, larger by one than in p revious years. The following table gives the monthly incidence of cases of the disease for each of the years under observation :T ABL E No . 1.
I 1925
1924
1925 1926
...
-
1
00 .
-
[
J anuary 00. February 00 . March 00. April 00 . 00 . May June 00' 00. July August 00. September October ... November . .. December 00'
00 .
.. . ... ... ... ... .. . ... 00.
...
00' .00 1
1 1
-
... "'1 -
...
.. . -
.. . .. .
... / ...
"'1 1
1927 1928
-
-
--
1
-
-
-
-
1
-
-
-
-
1
-
1 2 -
2 1
-
-
-
2
-
-
-
-
1929 1930
-
2
I
-
-
1
1928 1929
- -- - - - - - - - -1 1
-
-
-
...
1926 1927
--
-
-
-
-
-
-
--
-
-
-
-
!
1
Month ly incidence of cases for each year.
Wo Jon 3 2 I
0
Feb. Mar Aprtl Mo.!! June Ju(t; Au? Sept Oct Nov Oec.
--- --"\ V'- .. ~- V\1\.1 ~ IV •
~
--
e---e = coses
--
. Fig. N? 2.
--.....
f'-,./
- --
v
~
O. C.M
Monthly incidence of cases over six-year period. D
THE VETERINARY JOURNAL
38
Fig. o. 2 shows the monthly inc"idence of cases of the disease over the six-year period. Tuberculosis is not a seasonal disease : the finer months of the year show a notable proportion of cases, even June is not exempt ; the present writer has shown that June may a lso be an anxious month for the chicken raiser (Matheson, 2 and 3) TABLE No.2. I Percentage of total Percentage Flock o. ofl deaths contributed per P er No. Fowls· 1 by tuberculosis. population. thousand.
Year. 1924-1925 1925-1926 1926- 1927 1927-1928 1928-1929 1929- 1930 1924-1930
1 2 3 4 5 6
I
All
I
I
402 516 588 600 600 600
1 3 ,306 1
6.6 10. 81 9.75 5. 12 9.09 14.0
0.49 0.73 0.68 0.3 0.5 1.16
4.9 7 .3 6.8 3.0 5.0 11. 6
9.56
0.66
6.6
In considering the figures in table No.2, it must be remembered that we are dealing with high-grade flocks; grouping these together as in the bottom row, we find that out of 3,306 pullets coming under observation during a · period of six years, tuberculosis contributed 9.56% to the total number of deaths, and it is interesting t o compare this figure with that for a number of fowls of all grades exam ined during a period of thirteen years: Tuberculosis accounted for 11.08% of total deaths (Matheson, 4) The birds which ultimately perished of tuberculosis in the present investigation came from fourteen districts; from the same district and same place, twice; from the same district but not the same place, twice; otherwise the districts were distinct and widely separated in England and Scotland. The disease is widespread, but Great Britain is not alone in this respect; the disease is serious in America (Mohler, 5), and on the Continent of Eurofe (Beller, 6). With regard t o the occurrence of the disease in the pens, it is important to notice that so far the disease has never recurred in the same pen in any of the following years, and we have already p~inted out that one case only generally appears in one pen, that is, estimating the number of cases by the number of deaths ; the one bird may infect its pen-mates, but death from tuberculosis does not usually come t o them during th e year
AVIAN DIPHTHERITIC E TERITIS
39
of observation. The exceptions have been noticed above. Circumstances did not permit of the use of th e tuberculin test. Even when the disease has appeared in subsequent years in adjacent pens, or pens in prox imity, an average interval of more than two years separates the cases. The pens are disinfect ed, and th e soil covered with a dressing of lime after every case. At the present rate of progress the time will co me when every pen wi ll have had its case of tuberculosis, but that will be because the birds have brought the disease to the observation ground, not because they have contracted the disease from th e pen or ground. (r) (2)
(3) (4) (5 ) (fi)
REFERENCES . Matheson , D. C.: "The Methodical Exa min a ti on of th e Fow!. " I ndian V et. J our. Vol. 6. NO. 4. Matheson, D. C. (193 0 ) : ': Avian Coccidiosis. " Proceed ings Fourth World's Poultry Congress, London. Matheson, D. C. (r930) : "A Contribution to th e Epizootiology of Avian Coccidiosis." Indian V et. J our . Vo!. 7. NO . 2. Matheson , D. C. (1927): .. Preventable Losses from P oultry Dise'lses." Proceedings Third World's Poultry Congress, Otta wa , Canada. Mohler, J. R . (1930): .. R esearch Work of the Burea u of Anima l Industry on Poultry Diseases." Proceed ings Fourth World 's Poultry Congress, London. Bell er, K . (1930): .. Pou ltry Tuberculosis." Proceedings Fourth \ Vorld's Poultry Congress, London.
AVIAN DIPHTHERITIC ENTERITIS AND. SWINE FEVER. By JOHN P. RICE, B.Sc., M.R.C.V.S. Animal Diseases Division, Ministry of Agriculture, Strandtown, Belfast. WHILE diphtheritic enteritis in poultry is sometimes caused by the virus of fowl pox, an independent sporadic type of unknown
THE VETERINARY J OURNAL
STUDIES IN THE EPIZOOTIOLOGY OF AVIAN TUBERCULOSIS. By D . C . MATHhSON, F .R.C.V.S., D.V.S . M(V ict. ). From the Department of P athology , Bacteriology and Meat Inspection, The Royal (Dick) Veterinary College, Edinburgh. DURING the past six years the writer has had under observation for a period of twelve months each, six high-grade flocks consisting of from four hundred t o six hundred pullets, drawn from various parts of Great Britain ; housed under first class conditions; scientifically fed; and controlled by skilled management. The birds came under observation in October of one year and remained under observation till September of the following year. Each bird was carefully examined (Matheson, 1) before being allowed to enter the flock; any bird not in apparently good health was rejected. The comparatively small number in the first flock was due t o the rigorous eliminating examination, which , h owever, was justified subsequently by the improved type of bird that was presented for acceptance. The birds were arranged in groups of six, each group ha ving a separate pen and a separate grass run, providing ample accommodation . The breeds represented included: White Leghorn, White Wyandotte, Rhode Island R ed, Ancona, Black Leghorn, Light Sussex, Buff Rock, Barnevelder, Black Minorca, Exchequer Leghorn, Barred Rock, Cuckoo Leghorn.
N~
/926 / 9 27 1928
/9 2 4
/ 9 25
1925
1926 / 9 27 / 9 2 8
/929
1929
/930
7
/
6
5 4
_
r-..
/:/r'
3
2
./n -
r-.. _
'-'~
K'.x:(
/'
r-..
/ .I V V-- ./
/r'
/
-
~
/
/
-
-
..r{/
......,
......,
0 Dc.M
FiG N'? / 0- - - ~
=
otlt6reoks
•
•
=
cases
STUDIES IN EPIZOOTIOLOGY
37
Every bird dying during the period of observation was submitted to post-mortem examination in the writer 's laboratory. Tuberculosis was one of the first disease to make its appearance. Fig. No. 1 shows the number of outbreaks and the number of cases which occurred in each of the years under observation . It will be noticed tha t it was not until the last two years that more than one case occ urred in one pen. The sharp rise in the number of cases in the period 1929-1930 was due to the fact that in one pen several birds were affec ted. The actual number of outbreaks was, however, larger by one than in p revious years. The following table gives the monthly incidence of cases of the disease for each of the years under observation :T ABL E No . 1.
I 1925
1924
1925 1926
...
-
1
00 .
-
[
J anuary 00. February 00 . March 00. April 00 . 00 . May June 00' 00. July August 00. September October ... November . .. December 00'
00 .
.. . ... ... ... ... .. . ... 00.
...
00' .00 1
1 1
-
... "'1 -
...
.. . -
.. . .. .
... / ...
"'1 1
1927 1928
-
-
--
1
-
-
-
-
1
-
-
-
-
1
-
1 2 -
2 1
-
-
-
2
-
-
-
-
1929 1930
-
2
I
-
-
1
1928 1929
- -- - - - - - - - -1 1
-
-
-
...
1926 1927
--
-
-
-
-
-
-
--
-
-
-
-
!
1
Month ly incidence of cases for each year.
Wo Jon 3 2 I
0
Feb. Mar Aprtl Mo.!! June Ju(t; Au? Sept Oct Nov Oec.
--- --"\ V'- .. ~- V\1\.1 ~ IV •
~
--
e---e = coses
--
. Fig. N? 2.
--.....
f'-,./
- --
v
~
O. C.M
Monthly incidence of cases over six-year period. D
THE VETERINARY JOURNAL
38
Fig. o. 2 shows the monthly inc"idence of cases of the disease over the six-year period. Tuberculosis is not a seasonal disease : the finer months of the year show a notable proportion of cases, even June is not exempt ; the present writer has shown that June may a lso be an anxious month for the chicken raiser (Matheson, 2 and 3) TABLE No.2. I Percentage of total Percentage Flock o. ofl deaths contributed per P er No. Fowls· 1 by tuberculosis. population. thousand.
Year. 1924-1925 1925-1926 1926- 1927 1927-1928 1928-1929 1929- 1930 1924-1930
1 2 3 4 5 6
I
All
I
I
402 516 588 600 600 600
1 3 ,306 1
6.6 10. 81 9.75 5. 12 9.09 14.0
0.49 0.73 0.68 0.3 0.5 1.16
4.9 7 .3 6.8 3.0 5.0 11. 6
9.56
0.66
6.6
In considering the figures in table No.2, it must be remembered that we are dealing with high-grade flocks; grouping these together as in the bottom row, we find that out of 3,306 pullets coming under observation during a · period of six years, tuberculosis contributed 9.56% to the total number of deaths, and it is interesting t o compare this figure with that for a number of fowls of all grades exam ined during a period of thirteen years: Tuberculosis accounted for 11.08% of total deaths (Matheson, 4) The birds which ultimately perished of tuberculosis in the present investigation came from fourteen districts; from the same district and same place, twice; from the same district but not the same place, twice; otherwise the districts were distinct and widely separated in England and Scotland. The disease is widespread, but Great Britain is not alone in this respect; the disease is serious in America (Mohler, 5), and on the Continent of Eurofe (Beller, 6). With regard t o the occurrence of the disease in the pens, it is important to notice that so far the disease has never recurred in the same pen in any of the following years, and we have already p~inted out that one case only generally appears in one pen, that is, estimating the number of cases by the number of deaths ; the one bird may infect its pen-mates, but death from tuberculosis does not usually come t o them during th e year
AVIAN DIPHTHERITIC E TERITIS
39
of observation. The exceptions have been noticed above. Circumstances did not permit of the use of th e tuberculin test. Even when the disease has appeared in subsequent years in adjacent pens, or pens in prox imity, an average interval of more than two years separates the cases. The pens are disinfect ed, and th e soil covered with a dressing of lime after every case. At the present rate of progress the time will co me when every pen wi ll have had its case of tuberculosis, but that will be because the birds have brought the disease to the observation ground, not because they have contracted the disease from th e pen or ground. (r) (2)
(3) (4) (5 ) (fi)
REFERENCES . Matheson , D. C.: "The Methodical Exa min a ti on of th e Fow!. " I ndian V et. J our. Vol. 6. NO. 4. Matheson, D. C. (193 0 ) : ': Avian Coccidiosis. " Proceed ings Fourth World's Poultry Congress, London. Matheson, D. C. (r930) : "A Contribution to th e Epizootiology of Avian Coccidiosis." Indian V et. J our . Vo!. 7. NO . 2. Matheson , D. C. (1927): .. Preventable Losses from P oultry Dise'lses." Proceedings Third World's Poultry Congress, Otta wa , Canada. Mohler, J. R . (1930): .. R esearch Work of the Burea u of Anima l Industry on Poultry Diseases." Proceed ings Fourth World 's Poultry Congress, London. Bell er, K . (1930): .. Pou ltry Tuberculosis." Proceedings Fourth \ Vorld's Poultry Congress, London.
AVIAN DIPHTHERITIC ENTERITIS AND. SWINE FEVER. By JOHN P. RICE, B.Sc., M.R.C.V.S. Animal Diseases Division, Ministry of Agriculture, Strandtown, Belfast. WHILE diphtheritic enteritis in poultry is sometimes caused by the virus of fowl pox, an independent sporadic type of unknown