| dc.description.abstract | Fascioliasis is a global parasitic disease caused by
trematodes of the genus Fasciola. These causative agents belong
to two species of Fasciola, namely Fasciola gigantica and Fasciola
hepatica. In Kenya both species are known to cause the disease.
although Fasciola gigantica is regarded as the most important
species.
The mode of transmission of fascioliasis is well established,
and practical tactics exist on how to arrest the biological cycle
to prevent further transmission. However application of these
tactics either singly or in an integrated form has not been
effective in ridding off the cattle industry of this health problem.
While abattoir data acts as an indicator of the existence of
bovine fascioliasis in the field. it does not probably give an
accurate estimation of prevalence of the condition. In addition.
only a few surveys carried out by the V.I.L.s examined the factors
inffuenctng the -occurrence and distribution of bovine fascioliasis.
These factors have always been studied singly and therefore
their combined influence on the prevalence and distribution of,
the condition has not been determined. In order to improve on
these deficiencies, the present study was initiated with the
following objectives:
a) To update and improve on the approach of estimating
prevalences of bovine fascioliasis in Kenya using abattoir
data.
b) To investigate the factors influencing the distributions of
bovine fascioliasis with particular reference to
environment, animal husbandry systems, disease control
practices and cattle demographics.
Abattoir data on condemnation of bovine livers due to bovine
fascioliasis were compiled for the 1985 to 1990 period from 24
districts covered by the meat inspectorate section of the
Veterinary Department. In addition data based on diagnostic
records of the Veterinary Investigation Laboratories (V.I.Ls) were
also compiled for the same period. These data helped in
estimating trends of bovine fascioliasis as well as assessing the
prevalence estimates of the various geographical regions.
Livestock population figures were obtained from the Kenya
Rangeland Ecological Monitoring Unit and Ministry of Livestock
Development. Climatological data were obtained from Kenya
Meteorological Department.
From the abattoir data for the five year period (1985-1990)
the results indicated that districts could broadly be divided into
high risk districts with prevalence of over 40%, medium
prevalence districts with prevalences of between 10-39% and
low risk districts with prevalences of less than 100/0. The V.I.Ls
data showed variations in prevalences depending on the region
served by a particular laboratory. A major peak of mean monthly
prevalences occurred in March-May with a minor peak
occurring in September-November.
The field survey data was collected from six randomly
selected districts based on the Agricultural Research Foundation
Report of 1986. These were Nakuru, Kericho, Nyandarua
Machakos, Kwale and Kilifi. The farm data were used to better
improve the estimation of prevalences of bovine fascioliasis. A
total of 256 farms were sampled from the six districts surveyed.
A questionnaire covering all aspects of farm management, animal
husbandry practices, disease control practices and cattle
demographics was administered in each of the selected farms.
Faecal and serum samples from a total of 2434 bovines were' .
sampled. The faecal samples were analysed for Fasciola eggs
using the Faecal Sedimentation test, while the serum samples
were analysed using the ELISA test for antibodies against
Fasciola antigens.
From the results of these analyses, ,it was observed that farm
prevalences of bovine fascioliasis varied from district to district
in the following descending order, Kwale 32.6%, Kilifi 28.4%,
Machakos 14.3%, Nyandarua 12.5%, Kericho 3.4% and Nakuru
2.1%.
The results of logistic regression analysis showed that farm
prevalences were significantly influenced by various risk factors, '
for example grazing management, nutrition, availability of
housing, breed type and source of water.
An important objective of this study was to improve
prevalence estimates of bovine fascioliasis using farm data. The
results showed that areas previously reported to have had low
abattoir based prevalences of bovine fascioliasis particularly
Kwale (8.5%) and Kilifi (6.3%) showed relatively high farmbased
prevalences, whereas districts that had earlier been
reported to have high abattoir based prevalences e.g. Nakuru
(22.3%) and Kericho (40.7%) showed relatively low farm based
prevalences (less than 1o%). The results of this study therefore,
contradict those of the Agricultural Research Foundation Report
of 1986. A possible explanation for the changes in prevalences is
probably due to success in control measures directed against the
disease or a decline of the same. The conclusions drawn from
this study are:
a) Prevalence estimates based on abattoir and V.I.Ls data act
only as indicators of the existence of fascioliasis problem
in the country but not the true picture of the problem
within specific districts.
b) Risk factors namely. animal husbandry practices and
meteorologic factors are the most important factors
affecting the prevalence and distribution of bovine
fascioliasis.
c) Design of control measures against bovine fascioliasis
should be based on the combinations of the farm
management factors and animal husbandry practices. | en |
