HAEMATOLOGY OF EXPERIMENTAL CONTAGIOUS CAPRINE PLEUROPNEUMONIA
HAEMATOLOGY OF EXPERIMENTAL CONTAGIOUS CAPRINE PLEUROPNEUMONIA
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Date
1985-08
Authors
ALAFIATAYO, RUTH ABIMBOLA
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Abstract
The haematological picture of contagious
caprine pleuropneumonia (CCPP) induced in Savannah
Brown (SB) goats using the virulent Smith's strain
of Mycoplasma mycoides subsp capri was determined.
In the first animal experiment, 10 adult SB goats
were each inoculated intranasally with a total of
2.6 x 107 organisms contained in 5ml broth culture;
5 goats serving as controls received 5ml sterile
broth intranasally, while another 4 goats were kept
as stand-by to replace any goat that died of CCPP.
The following haematologic parameters were determined
2 weeks and 1 week pre-inoculation, on day of
inoculation (day 0), 3 days, 7 days, 11 days, 2 weeks,
3 weeks, 4 weeks, 6 weeks, 7 weeks, 8 weeks, 9 weeks
10 weeks, 12 weeks, 14 weeks, and 17 weeks postinoculation:
Packed Cell Volume (PCV), Haemoglobin
concentration (Hb), Total Red and White Blood Cell
Counts (RBC and WBC), relative and absolute differential
counts and total protein level. Some goats
survived infection for only 1 week and this first
study was terminated 17 weeks post-inoculation,
providing data on both acute and chronic stages of
CCPP,, In a repeat animal experiment, 6 SB goats
received 1.0 x 101 0 organisms intranasally each,
also in 5ml broth culture, and 4 goats received
5ml sterile broth culture as control. Unfortunatelyall
infected goats died per-acutely or acutely
within 7 days, such that the chronic blood picture
could not be assessed, but these goats provided
blood picture of a typical severe CCPP.
Clinical signs of disease were observed and
post mortem examination was carried out on all
animals that died and on those killed at the
termination of each study. Mycoplasma re-isolation
attempts were made from the trachea and lungs of
each goat, and lung sections were prepared routinely
for histopathologic examinations.
In animal experiment I, all infected goats
showed elevated body temperature, coughing,
inappetance, typical pleuritic sound on auscultation,
and 3 died at 5 and 6 days post-inoculation.
In animal experiment II, all infected goats showed
similar clinical signs that were more marked and
they died within 7 days post-inoculation, some as
early as 48 hours post-inoculation. A mycoplasma
confirmed by the growth-inhibition test as M. mycoides
subsp. capri was isolated, from the trachea and lungs
of all goats that died per-acutely or acutely, and from three goats killed 17 weeks post-inoculation.
No mycoplasma was isolated from any control goat.
Gross lesions observed in goats that died were of
classical CCPP. They included heavy fibrinous
deposits on lung and thoracic cage, pleural adhesions
to pericardium and thorax, severe pericarditis and
hydropericadium (about 30mls) and hydrothorax
(about 200mls), darkened consolidation of all lobes
of the right lung and the ventral side of the left
diaphragmatic lobe, enlargement of the bronchial
and mediastinal lymph nodes. Histologically, there
was cellular infilteration of the alveoli, bronchioles
and bronchi. Cells were mainly neutrophils, but
there were some lymphocytes and plasma cells. A lot
of fibrin strands infilterated the alveoli,
bronchioles and the interlobular septae. There was
vascular congestion, and dilation of the lymphatic
vessels.
The haematologic parameters were subjected to
statistical analysis using the student t-test.
Values of P 0.05 were considered significant. During
the acute stage of infection, the mean values of
total WBC counts, neutrophils and bands were higher
in the infected goats than in control goats (P 0.05).
This indicates a leukocytosis and neutrophilia with a regenerative left shift. During later stages, the
values gradually returned to normal level, i.e.
comparable to values from control goats or preinoculation
data. On the other hand, PCV, Hb, RBC
counts, and also total blood protein values were not
significantly affected during CCPP (P>0.05).
It is concluded that acute CCPP results in
leukocytosis and neutrophilia with a regenerative left
shift, but PCV, Hb, RBC and total protein values
are not significantly affected. Moreover, the
Smith's strain of M. mycoides subsp. capri is
confirmed to be very highly pathogenic to Savannah
Brown goats of Nigeria.
Description
A Thesis submitted to the Postgraduate
School, Ahmadu Bello University, in
partial fulfillment of the requirements
for the degree of Master of Science (M.Sc.)
Department of Pathology & Microbiology,
Faculty of Veterinary Medicine,
Ahmadu Bello University, Zaria.
Keywords
HAEMATOLOGY,, EXPERIMENTAL,, CONTAGIOUS,, CAPRINE,, PLEUROPNEUMONIA,