PREVALENCE, IMMUNOPROPHYLAXIS AND MECHANISM OF IMMUNITY TO Sarcoptes scabiei INFESTATION IN PIGS.
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Date
2008
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Birsa Agricultural University, Kanke, Ranchi, Jharkhand
Abstract
The thesis incorporates the results of investigation
on the prevalence of Sarcoptes scabiei in and around Ranchi,
immunization with whole mite extract antigen and induction of
immune response in pigs as a result of immunization.
Prevalence of S. scabiei in and around Ranchi was
studied in accordance with age, breed, season and
managemental condition like organized and unorganized pig
farming. The overall seroprevalence of mites affecting pigs was
estimated 56.81 percent in T& D and 70 percent in Desi. The
age-wise prevalence indicated that pigs above 100 days of age
were having the highest 42.85 percent in T & D and 84.37
percent in Desi and the animals up to 56 days age had the lowest
13.63 percent in T & D and 27.50 percent in Desi infestation.
The desi pigs were found more susceptible to mite
infestation as compared to T & D.
Mite infestation was more common in winter ( 46.66 %
T & D, 79.54 % Desi and 45.16% Landrace) and rainy season
(40.90% T & D, 76.19 % Desi and 43.75%Landrace) as compared
to summer season (21.73% T&D , 42.22 % Desi and 23.33%
Landrace ).
Hotel /Kitchen waste fed pigs were found more
susceptible (47.82 %) as compared to grazing pigs ( 39.02% )
while mite infestation was more common in organized farm ( 60%
) as compared to unorganized farm ( 35.71% ) .
Management wise mite prevalence study indicated that
pigs maintained on kachcha floor were having the highest
(82.93% ) and the pigs maintained on pacca floor were having
lowest ( 64.44% ) infestation while in poor disease managemental
condition pigs were found more susceptible ( 70% ) as compared
to good managemental condition (22.85%).
The result of the haematological studies showed
that no significant change in haemoglobin and packed cell
volume was found just after immunization . However, significant
reduction in value was found on 90th and 150th day in group II
and on 150th day in group I . In addition, the number of
circulating lymphocytes, eosinophils and basophills significantly
increased but neutrophil count decreased and these change was
more marked on 30th and 60th day of observation.
The results of the biochemical studies revealed that
immunization resulted in significant decrease in albumin value.
Reduction in the value was more marked on 30th and 60th day of
observation. There was significant increase in serum globulin
which is suggestive of an immunological response in the host to
immunization.
Intradermal injections of whole mite extract antigens
resulted in the development of antigen –specific delayed
hypersensitivity skin reaction in pigs immunized with WMEAg.
Delayed type of hypersensitivity reaction was more pronounced
at 48 hours, characterised by swelling and infiltration of large
number of lymphocytes and macrophage .
Serum precipitating antibodies to antigens of whole
mite extract were detected by double immuno diffusion test .
WME-Ag reacted with their homologous antisera but not with
heterologous antisera indicating the presence of stage –specific
antigens in whole mite extract . The presence of antibodies at the
time when resistance was exhibited might indicate protective
nature of antibodies . It appears, immunization with antigens
comprising whole mite extract could afford better protection.
Humoral antibody response of pigs to WMEAg when
assessed by sandwich ELISA on day 0, 21, 60 , 90 and 150
showed significant difference in antibody level as compared to
controls . However, significant antibody level could only be
detected on 21st day post immunization which continued till day
150 with a peak on 21st , 60th and 90th day in group I and 21st
day in group II . These results indicated significantly higher
antibody level in immunized pigs and WMEAg is immunogenic
From the results of the present investigation it is
presumed that acquired resistance to S.scabiei in pigs has an
immunological basis and the immune effector mechanism
associated are hypersensitivity reactions mediated by anti –mite
antibodies and cell mediated immunity.
Description
PREVALENCE, IMMUNOPROPHYLAXIS AND MECHANISM OF IMMUNITY TO Sarcoptes scabiei INFESTATION IN PIGS.
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