Assesment of Methods for the Diagnosis of Malignant Catarrhal Fever (Mcf) and Knowledge, Attitudes and Practices Regarding Mcf at Kapiti Plains Ranch
Abstract
Malignant catarrhal fever (MCF) is a sporadic but severe viral disease that affects cattle and
is transmitted from wildebeest calves following the wildebeest calving period. Up to now, an
effective vaccine or treatment for this disease does not exist hence infected cattle often die
causing huge economic losses to both small scale and large scale cattle farmers. The disease
has also been associated with human wildlife conflicts and environmental degradation.
To date there has been no diagnostics based research nor qualitative assessment of the disease
conducted at the Kapiti Plains Ranch Limited, Kenya. This study was therefore aimed to
assess the methods for diagnosis and knowledge, attitudes and practises (KAP) of MCF on
this ranch.
Archived samples (n=123) of clinically confirmed cases of wildebeest associated malignant
catarrhal fever (WA-MCF) collected from 2014 to 2016 were tested by nested polymerase
chain reaction (PCR) and indirect enzyme linked immunorsorbent assay (ELISA) to evaluate
the performance in confirming the clinical cases in the laboratory. Evaluation of the
performance of the tests was done in three ways. First, the sensitivity (Se) and specificity
(Sp) of indirect ELISA was calculated using nested PCR as a gold standard. Second, the
level of agreement between the two tests was assessed by the Cohen’s kappa statistic. Third,
the Bayesian agreement index (B.A.I) tested the agreement between these tests in the absence
of a gold standard. A KAP study using semi-structured questionnaires (SSQs) with a mix of
closed and open ended questions were issued to 60 staff of the ranch to identify various
perceptions of WA-MCF in terms of recognition, clinical signs, seasonality of the disease and
action taken during the manifestation of the disease. Also, a comparative approach of WAMCF
to Contagious Bovine Pleuropneumonia (CBPP), East Coast Fever (ECF), Foot and
Mouth Disease (FMD) and Lumpy Skin Disease (LSD) using proportional piling was used to
investigate the perception of mortality, annual cases and costs of WA-MCF to these diseases.
In addition the KAP study also sought the ways of controlling WA-MCF from the
respondents at the ranch.
Of the 123 clinical samples, 62.6% (77/123) were positive by indirect ELISA while 94.3%
(116/123) samples were positive by nested PCR. The sensitivity and specificity of the ELISA
using nested PCR as a gold standard were 63.8% (95% C.I. 55 -72%) and 57.1% (95% C.I.
25 -85%) respectively. The kappa statistic revealed a value of 0.05 between these tests while
the B.A.I. agreement for these assays was better in the positive than in the negative direction
with B.A.I. of 76.7% (95% B.C.I. 70-83%) in the positive direction and 15.1% (95% B.C.I.
4-31%) in the negative direction. The KAP study revealed diverse views towards WA-MCF
in terms of recognition, clinical signs, seasonality of the disease and action taken during the
manifestation of the disease. The disease was revealed to be a very important disease with
respect to cattle mortality while being the least important disease with respect to the number
of annual cases as the respondents farms are away from wildebeest grazing areas and also in
terms of management costs as it lacks an effective vaccine and treatment. A range of methods
were suggested for controlling WA-MCF in the case that it could occur in the individual farm
of the respondents with the most common being to chase the wildebeest away.
The results of this study suggest that when laboratory diagnosis of WA-MCF is needed,
nested PCR performs better in confirming the clinical cases of WA-MCF than indirect
ELISA. However the logistics of nested PCR make it an unsuitable tool for diagnosing WAMCF
as it is expensive, needs well trained personnel and specialized equipment. Future
research on WA-MCF should focus on the development of cheap penside techniques for
rapid diagnosis during outbreaks. The KAP study demonstrated that most respondents were
able to recognize WA-MCF, which will assist in the management of the disease as they can
report earlier and take action during outbreaks.
Kapiti Plains Ranch experiences considerable economic losses from WA-MCF, which
requires a long-term solution for the wildebeest and cattle to coexist on this ranch.
Development of a vaccine would be a long term solution as this will reduce cattle deaths and
ensure coexistence between the wildebeests and cattle hence reducing human wildlife
conflicts. Further work should be conducted in high risk areas to get a better insight of
impacts of the disease. This will enable livestock researchers to collaborate with the cattle
owners to give them updated information on new control methods for the disease.
Publisher
University of Nairobi
Rights
Attribution-NonCommercial-NoDerivs 3.0 United StatesUsage Rights
http://creativecommons.org/licenses/by-nc-nd/3.0/us/Collections
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