EPIDEMIOLOGICAL INVESTIGATION OF TETANUS: A MATCHED CASE CONTROL STUDY AND EVALUATION OF TREATMENT OPTIONS IN EQUINES IN CENTRAL OROMIA, ETHIOPIA
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Date
2017-06
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Abstract
Although tetanus is considered as an important disease of equines in Ethiopia, little is
known about its epidemiology, treatment options and impact on the livelihoods. This
epidemiological study was carried out with the main objectives of identification of risk
factors, evaluation of efficacy of different treatment options and description of
spatiotemporal occurrence and clinical characteristics of the disease. A matched case
control study was conducted to identify putative risk factors from cases admitted to the
Donkey Sanctuary clinics in Bishoftu and Merkato, at the College of Veterinary
Medicine and Agriculture of Addis Ababa University. The clinical case records of
equines diagnosed with tetanus were retrieved between January 2008 and May 2017. For
each case two controls were drawn from the same villages that cases were originated
from. Matching was done for age and sex. Randomized control trial was used to evaluate
the efficacy of procaine penicillin G, metronidazole and combination of both drugs on the
survival and improvement in clinical signs. Isolation of Cl. tetani was done from soil
samples collected from the animals’ environment. Analysis of medical records of equines
diagnosed with tetanus showed that the disease was spatially aggregated in Gerbicha
28.14 % (n=65) and Gicho Gerbabo 16.02 % (n=37) peasant associations of the Ada’a
district. Temporally, the cases of tetanus were found to occur during the summer seasons.
There was statistically significant association (p<0.05) observed between the presence of
wound and survival of equines affected with tetanus. The grade of tetanus at the time of
presentation to clinics was also significantly associated with survival. Certain clinical
signs (prognostic signs) were significantly associated with survival of equines diagnosed
with tetanus. Besides, duration of illness before hospitalization and duration of
hospitalization had significant effect (p<0.001) on the survival. The results of matched
case control study revealed that the presence of visible wound increases the risk of
acquiring tetanus 10.35 times as compared to those animals which didn’t (p < 0.001).
Equines with good and moderate body conditions had respectively, 22.27 and 3.51 times
higher risk of acquiring tetanus than equines with poor body conditions. The results of
experimental study indicated that metronidazole injection caused highest survival (80 %)
followed by combination of metronidazole and procaine penicillin G (66.67%) whereas penicillin G alone showed lowest survival (33.33%). Better improvement of clinical signs
of tetanus was also observed in donkeys treated with metronidazole than the other
treatment groups. The present study showed that tetanus remains an important disease
with higher case fatality and highlights a considerable welfare and economic significance
in equines. Probable recommendations to limit the risk factors including management,
prevention of wound and education of owners are suggested. Furthermore,
epidemiological studies with the elucidation of the use of metronidazole are warranted.
Description
MSC Thesis
Keywords
Matched Case Control, Equine, Risk factors, Tetanus