DISCUSSION
This study reports the first field treatment trial using Tri-Solfen® as
a therapy for the clinical management of FMD in Africa, comparing the
clinical efficacy of this novel therapy with the commonly used
parenteral antibiotic treatment Moore-Oxy® and animals remaining
untreated. Despite necessary limitations due to resources availability
on numbers of farmers and cattle recruited for the trial, the results
and all participants, considered it was very successful, with high
levels of appreciation by participants for their involvement and the
clear results obtained.
Lesion healing scores across the three groups revealed superior results
for the TS-treated cohort and although the MO-treated cohort also
achieved a reasonable score, the untreated control animals had lesions
persisting for in excess of 2 weeks. Although a subjective measurement,
these scores provide a useful indication of the healing rate of FMD
lesions in field conditions in Cameroon.
Similarly, appetite scores were highest in the TS-treated cohort,
indicating that the treatment supported the rapid return of appetite,
even after 3 days. Superior appetite scores in this group were recorded
at each data collection between day 3 and day 15, with the cohort
receiving treatment with MO also having reasonable appetite scores
between days 3 and 15. The control cohort cattle had poor appetite
scores throughout, indicating appetite remains poor for in excess of 2
weeks when FMD remains untreated.
Lesion size was measured (in cm) at six data collection intervals, with
the FMD infected cattle lesion size decreasing rapidly in the TS-treated
cohort. By day 6 this cohort was performing well with average lesion
size at 0.33 cm, despite commencing in the trial with higher average
lesion size. By day 9, the lesions in the TS-treated cohort had almost
entirely disappeared, remaining at 0 cm through day 12 and 15.
Interestingly, the control group average lesion size increased as the
trial progressed. In the MO-treated cohort, the average lesion size
decreased until day 12, where it was recorded to increase from 0.17 cm
to 0.75 cm at day 15. Stage of infection may have affected the study
here, particularly as the lesion size in the control cohort was 0 cm at
trial on day 0.
The farmer observations of clinical impacts also provided interesting
results which could be used as animal welfare indicators as well as
indicators of clinical response to the treatments. The mobility of all
12 cattle in the TS-treated cohort returned immediately, suggesting this
is a very useful therapy to enable cattle to walk and gain access to
water and feed. In the MO-treated cohort, 10 of the animals also
immediately returned to walking. However, of the control group, only
five had immediate mobility and four animals did not return to walking
even by day 15. There was one animal in the MO-treated cohort that did
not return to mobility until day 12. In total, 7/36 (19.4%) cattle had
not returned to mobility by day 9, indicating that FMD is a severe
disease as it renders animals immobile and that although FMD is
considered a low mortality disease, the animal welfare impacts are
considerable.
As oral vesicular lesions can have significant impacts on animal
behaviours, recording the number of days the animals were anorexic was
considered important. In total, 11/12 cattle in the TS-treated cohort
were reported to be eating the same day as treatment (day 0). This
compared to 9/12 cattle in the MO-treated cohort, with only 2/12 in the
control cohort, with 9/12 of these untreated cattle remaining anorexic
until day 15. Further, salivation is a common clinical sign with cattle
with vesicular disease, considered an overt indicator of oral lesions
and presumably oral pain. In all three cohorts the majority of cattle
had ceased salivating at day 0, with the TS-treated cohort achieving
11/12, MO-treated cohort 10/12 and the controls 8/12.
Farmer reports of visible lameness of trial cattle indicated that 9/12
cattle in the TS-treated cohort ceased any lameness at day 0, compared
to 5/12 in the MO-treated cohort and 3/12 in the controls. By day 6, no
further cattle in the TS-treated cohort showed any lameness compared to
5/12 cattle in the MO-treated cohort still showing lameness by days 12
and 15, with lameness only ceasing by day 15 in 9/12 control cattle. For
the question of how many days prior to cattle returning to grazing,
mixed results were recorded. In the control cohort, 9/12 were reported
grazing by day 0, with 8/12 in the TS-treated cohort returned to grazing
by day 3 and all 12/12 in the MO-treated cohort returning to grazing by
day 6.
When asked for a broad overview of treatments applied to FMD, six
options were provided, including antibiotic formulations, traditional
drugs, insecticides and petrol. Without speculating on the therapeutic
potential of each treatment, it does indicate that farmers and
paraveterinarians are inclined to treat affected animals withsomething . The data on costs of treatment suggest there are only
minimal differences between treatments and that cost should not be an
impediment to changing of treatment choice.
Field studies involving animal treatments with assessments of clinical
impacts are challenging and subject to potential bias, reflected in the
limited published literature on FMD therapy. However, the results
obtained in this study demonstrate the superior clinical efficacy of a
single application to FMD lesions of the TS topical anaesthetic wound
formulation. The participating farmers reported a 100% appreciation for
the product in the treatment of FMD and expressed they were happy to
have this product available for use in the region. These findings were
consistent with those from a recently reported clinical investigation of
TS therapy for FMD in Laos (Windsor et al, 2020) and reports of the use
of this product for FMD in other countries in Africa, including Niger,
Nigeria, and Kenya. This study in Cameroon provides the quantitative
assessment that confirm that TS is efficacious in hastening clinical
recoveries, immediately addressing pain and invoking more rapid healing
of FMD lesions, as observed qualitatively in Laos (Windsor et al, 2020).
As this innovation provides superior animal welfare outcomes for animals
suffering from FMD, without the risks of AMR that arise from the more
typical therapies in use for FMD globally, efforts to promote this new
therapeutic approach should be supported.