Sero-Epidemiology and Spatial Distribution of Peste Des Petits Ruminants Virus Antibodies in Some Selected Pastoral Areas of Somali Regional State, Ethiopia
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Date
2016-06
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Addis Ababauniversity
Abstract
A cross sectional study design with a 2 stage cluster sampling was conducted in some selected pastoral areas of Somali regional state from November to May 2015/16. The study was aimed at determining the serological status of PPR disease in sheep and goats and identifying animal and flock level risk factors in the selected Afder, and Liben zones of Somali regional state. And finally, the national status of PPR from disease outbreak reports was assessed from retrospective data. A total of 798 serum (582 goats and 216 sheep) from 19 Kebeles (peasant associations) across 8 Districts were investigated. PA level prevalence was variable (12%-64%) and the difference was significant (X2 =53.3 P= 0.000). At District level, the prevalence of the disease was recorded in descending order as Dolo Bay 52% ( CI95% = 41-63), Dolo Ado 42% (CI95%= 36-48), Hudet 40% (CI95%=30-52), Chereti 40% (CI95%= 26-57), Gorobeqeqsa 40% (CI95%= 31-50), Guradhemole 38% (CI95%= 28-49), Filtu 36% (CI95%= 22-52) and Moyale 30% (CI95%= 20-41). There was no significance difference in the proportion of sero-positives between Districts (X2= 7.46 p= 0.382). The overall true prevalence was 43%. Furthermore, the prevalence in sheep 39% (CI95%= 32-46) was found insignificant (X2=0.49 P= 0.483) when compared with goats 42% (CI95%= 38-46). The true prevalence of PPR in Sheep and goats was 41% and 44%, respectively. In addition, small ruminants aged between 36-48 months had recorded the highest prevalence 58% (CI95%= 49-66) out of all age groups. There was quite significant difference in sero-positivity among the age groups sampled (X2= 42.55 p= 0.000). Female small ruminants had a statistically greater sero-prevalence rate 44% when compared with males 26% (X2= 16.4 P= 0.000). Likewise, the likelihood of occurrence of PPR in female sheep and goats were 2.5 times more than its occurrence in males (OR= 2.5). The overall true flock prevalence was found to be 104% considering at least one positive in a flock. In the multivariable logistic model for both sheep and goats age group, origin and altitude were found the risk factors. However, more disease predictors were identified after adjusting the cluster effect of PAs and herds using multilevel mixed-effect logistic regression models. Therefore, in the multilevel mixed-effect logistic regression age group, origin, altitude, production system and water source were the most likely disease predictors of PPR disease in small ruminants and the variables were fit in the model using likelihood-ratio test (P= 0.000). Retrospectively, a
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total of 1282 outbreaks were reported nationally across all regions in the 10 year period. The detection of PPR virus antibodies in all PAs and Districts suggest that the wide circulation of the virus in the study area. Hence, to curb the wide spread of the disease, strategic vaccination scheme should be followed along with training to field veterinarians and community animal health workers (CAHWS). Besides, it is recommended to conduct further studies on the characteristic of the virus circulating in the study areas plus to investigate the role of camels, cattle and wild ruminants in the epidemiology of PPR which could be a milestone in the eradication of the disease.
Key words: Cluster, Epidemiology, Flock, Goat, PPR, Prevalence, Risk Factors, Sheep, Somali region
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Keywords
Cluster, Epidemiology, Flock, Goat, PPR, Goat PPR Prevalence, Risk Factors Sheep, Risk Factors Sheep