الفهرس 
LituratureOnly 14 pages are availabe for public view
 |  | from | 116 |  |  |
| | | from | 116 | | |
Abstract
In between spring 2008 to spring 2009, 800 sheep of different ages,
sex and breeds had been investigated clinically and laboratory for
dedection of enterotoxaemia cases. Seventy fecal samples and 130
samples of intestinal content had been collected from clinically diseased
and dead sheep. Fifty fecal samples and fifty intestinal content of
clinically healthy sheep and 100 soil samples had been collected. All
these samples were examined bacteriologically for isolation of
clostridium perferingens. The isolates had been typed using multiplex
PCR. All isolates had been examined for the presence of newly
discovered Cpb2 gene which responsible for β2 toxin production.
Histopathological study had been done. Finally comparative study on the
immune response for 3 commercial polyvalent clostridial vaccines had
been done using ELISA technique to know the most efficient one of
them.
The clinical findings associated clostridium enterotoxaemia were
sudden death of few cases without previous illness followed by increase
in number of deaths through the next week. In lambs there were sever
diarrhea streaked with blood, stopping of suckling, depression and death.
In older lambs and adult the clinical findings were progressive weakness,
depression for two days proceeding death. Other cases showing nervous
signs such as incoordination and convulsive movement of head and neck.
The postmortem findings were bloody fluid in body cavities, rumen
overloaded with ingesta, the small intestine was severly congested filled
with gases, and the brain with its meninges were congested. In some
cases congestion of kidneys and liver was observed.
The characteristic histopathological changes found in brain and
kidneys. Congestion, prevascular oedema, prevascular haemorrhages with
malacia in the former while in kidneys there were red blood cells
Summary and conclusions
infiltration in Bowman’s space, medullary haemorrhages and necrosis in
proximal and distal convoluted tubules.
The epidemilogical findings of clostridial enterotoxaemia revealed
that the mordidity, mortality and the case fatility rates were 25%, 16.25%
and 65%, respectively. The incidence of disease in the male and female
sheep was 28.12% and 22.91%, respectively. The incidence of bacterial
isolation in male and female sheep were 62.22% and 56.36%
respectively. The incidence of type A infection in lamb under 3 months
of age, lamb from 3 to 12months and in sheep over one year were 2.54%,
10.2% and 2.88%, respectively; The incidence of type B infection were
10.17%, 8.47% and 0%, respectively; The incidence of type D infection
were 0%, 2.54% and 43.22%, respectivel.The incidence of disease and
bacterial isolation in Braky and Baladi sheep was 26.66% &22.85% and
58.33% & 60%, respectively.
The incidence of disease bacterial isolation and during spring,
winter, autumn and summer was 49%, 26.63%, 15.55% & 8% and
65.30%, 68.96%, 35.71% & 25%, respectively.
The incidence of isolation of clostridium perfringens from diseased
and dead sheep, apparently healthy sheep and soil was 59% and 12% and
41% (13% from village soil and 28% from newly reclaimed soil),
respectively.
Typing of clostridium perfringens isolates from soil, apparently
healthy sheep and clinically diseased sheep by multiplex PCR revealed
that the percentage of type A was 45.03%, 3.5% and 24.56%,
respectively. The percentage of type B was 14.61%, 0% and 12.86%,
respectively. The percentage of type D was 40.35%, 3.5% and 31.57%,
respectively. Molecular screening of isolated strains revealed the absence
of Cpb2 gene.
Type A and B commercial polyvalent clostridial vaccines produced
high level of antibody titers in vaccinated sheep compared by type C.
Summary and conclusions
from the previous results we conconcluded that:
1- The most characteristics clinical finding of clostridial
enterotoxaemia in sheep was sudden death of few cases without
proceding signs followed by increasing of mortalities through the
following days.
2- The post mortem findings that suggestive for clostridial
enterotoxaemia were severly congested small intestine with bloody
content, bloody fluid in body cavities and brain odema and congestion.
3- The histopathological picture of noninflammatory changes in
brain and kidneys were suggestive for clostridial enterotoxaemia.
4- Infection by clostridium perfringens type A age reported in all age
groups. Infection by clostridium perfringens type B reported only in
sheep under ione year of age . Infection by clostridium perfringens type D
mainly reported in sheep over 12 month of age. Most cases occurred
during spring and winter seasons. Sex and breed of sheep did not
significantly affecting the incidence of disease.
5- Soil consider the main source of infection for sheep. The
incidence of isolation of clostridium perfringens from Newly reclaimed
soil was higher than that from village soil.
6- Multiplex PCR considered as easy, rapid and accurate technique
for typing of clostridium perfringens isolates.
7- Clostridium perfringens types A and D were the more frequently
isolated strains from all types of samples than type B clostridium
perfringens.
8- Cpb2 gene which responsible for β2 toxin production could not be
detected from any isolates.
Summary and conclusions
We recommended the following:
1- The changes in the course of clostridial enterotoxaemia in sheep
should be considered during field diagnosis.
2- Sheep breeders should elevate the control measures especially in
newly reclaimed area and during winter and spring.
3- Vaccination should be repeated every 4 months in endemic areaes.
4- Application of biosecurity in sheep farms with regular vaccination
programme.
5- Molecular typing of clostridium perfringens isolates using
multiplex PCR have several advantages as rapid, accurate and
allowed subtyping of isolates by detection of new genes.
6- Type A clostridium perfringens should be included within the
local and imported polyvalent clostridial vaccines to ensure
complete protection of the sheep.
7- Regular and periodic evaluation of the commercial vaccines in
different laboratories with informing the producers about the best
one to use.
8- Further studies should be applied on the Cpb2 gene in clostridium
perfringens isolates isolated from sheep and other animal species to
understand its role and importance in diseaes production and its
prevalence among animal species.
9- Further studies should be done to evaluate the immune response
against each components of different polyvalent clostridial
vaccines.