| dc.description.abstract | A comprehensive epidemiological study of the Kenya East Coast Fever
(ECF) control program was carried out. A descriptive account of the
situation which led to its initiation in 1904 and introductions of
various control tactics and their modifications over time was given.
Epidemiological analyses of the program were carried out using data
collected from each of the 40 districts of Kenya for the 1976 to 1986
period. These analyses were applied to the data from each of the two
groups of tick control districts, i.e., 20 Project and 20 Non-project
Districts. Statistical techniques used in these analyses were repeatedmeasures
of analysis of variance and covariance, multiple linear
regression, ,all-possible regressions and stepwise discriminant analysis.
Temporal trends in the incidence rate of ECF infection in cattle
populations of the Project Districts overall showed a decline between
1976 and 1979 remaining fairly stable at the 1979 level. But, graphical
exploration of each district's annual ECF incidence rates showed that
these Project Districts were comprised of 11 districts with fairly
regular declines in incidence (designated Progress Districts) and 9
districts with irregular incidence patterns. Cattle density and
rainfall were the variables which differentiated between Progress and
Nonprogress Districts. It was suggested that these two variables should
be considered in future control plans. In Non-project Districts the ECF
mean incidence rates increased significantly over time. Generally, the
expected progress toward the goal of the control program, eventual
eradication of ECF in Kenya, was not apparent in this study.
The variables influencing year to year variations in incidence of
ECF infection in cattle were analyzed. The number of dip tanks and the
proportions of grade cattle were related positively to the ECF incidence
rate and were the "best" predictor variables of the disease in Project
Districts. In the Non-project Districts the "best" predictor variables
were the size of the cattle population (negatively related to the ECF
incidence rate) and the human population density (positively related to
the ECF incidence rate). These results were discussed particularly in
reference to future changes in the control program.
The management of dip tank-bath acaricide concentrations was below
the expected level. The majority of samples submitted for testing
contained incorrect acaricide strengths (i.e., under- or over-strength).
In addition, the rate of sample submission for acaricide testing also
was below expectation. Future improvement of the management of dip tankbaths
was discussed.
Comparison between incidence rates of ECF and anaplasmosis showed
that the incidence of anaplasmosis was higher than that of ECF in the
Project Districts. The apparent lack of impact of cattle dipping on
anaplasmosis relative to ECF was used to formulate the hypothesis that
mechanical transmission (by e.g., hematophagous insects) influenced
the observed results. Further research to disprove or prove the
hypothesis was recommended. In the Non-project Districts incidence rates
of anaplasmosis and ECF were fairly similar. Mass control of tick-borne
diseases by cattle dipping was discussed in view of the possibility of
there being an ECF vaccine in the future.
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