Discussion on a Selection of Key Scientific Articles

 

Analysis of risk factors in the management of foot-and-mouth disease in Turkey

Turkish Journal of Veterinary and Animal Sciences, 40 (1), pp. 1-6, Şentürk, B., Yalçin, C., Akçay, A., 2016.

Key Thoughts: By demonstrating that there is a direct relationship between risk analysis and disease outbreaks, this study shows that a robust risk analysis can be used to target appropriate measures to improve disease control. It helps move from a blanket approach, where the country is treated as a single problem, to one where specific measures can be used appropriately. This will further enable better use of resources. In this particular case, relating to the Samsun Province in Turkey, it is evident that certain districts are at higher risk than others, and that this risk correlates to specific factors such as animal movement, geography, and both human and animal population density.

Article Review:  The objective of this study was to provide a risk analysis of the situation in Turkey, and to learn if disease outbreaks can be predicted according to the risk.

Many studies have looked at the economic costs of FMD. Production losses and vaccination are considered to cost between 6.6 to 21 billion dollars in endemic countries. The costs for disease control can be high, and methods to improve control measures should be investigated. The average annual number of outbreaks in Turkey between 2006 and 2013 was 1046. Despite the introduction of controls, the numbers have continued to increase in recent years. This makes Turkey an appropriate subject for risk evaluation.

The study focused on the Samsun Province, and assessed the following risk factors: input infrastructure (feed mills and dealers), process infrastructure (slaughterhouses, processing plants, cold stores), production infrastructure (species, number of animals), focus products (milk, meat), scale of enterprise, movement, and marketing infrastructure. All animals susceptible to FMD were included. A progressive clustering analysis was then used to evaluate the risks and group the data. Risk variables were grouped as very low, low, moderate, or high, and total risk scores of districts were obtained. When the Spearman correlation coefficient was calculated, there was a strong positive correlation (72%) between the total risk scores and the number of outbreaks in the district.

By identifying high-risk districts, it is then possible to correctly implement higher protection and control measures. Stakeholders throughout the food chain must be involved in the planning and implementation of controls, it is also useful to identify the multiple links in the system.

This analysis demonstrates that FMD management needs to be improved. Further analysis at the district and province levels can assist in the development of new approaches. For instance, the most important single factor with the strongest correlation to outbreaks was the movement of animals into a district. Therefore, precise assessment of movement risks should be a priority. In addition, geographical features, as well as both human and animal population size, lead to clusters of risk.

 

Seroprevalence, distribution and risk factor for peste des petits ruminants (PPR) in Algeria

Veterinary Medicine, 122 (1-2), pp. 205-210, Kardjadj, M., Kouidri, B., Metref, D., Luka, P.D., Ben-Mahdi, M.H., 2015.

Key Thoughts:  From first being identified in the 1940’s, peste des petits ruminants (PPR) has been gradually spreading. In the last decade, the spread has hastened and the threat of new introductions has increased. The disease was first reported in Algeria in 2011, but within a year PPR had reached the centre of the country. This study, conducted in 2014, shows that the overall flock prevalence was 30.45% and there was no significant difference among the regions. This demonstrates the speed at which PPR can spread throughout a country and suggests that early warning systems paired with good control measures are necessary. For countries in Southern Europe and Central Asia, this study provides useful information to help develop improved strategies against PPR.

Article Review:  PPR is a highly contagious, notifiable disease of sheep and goats that has spread across Africa, the Middle East and Asia. The morbidity and mortality rate can be particularly high, up to 90%, depending on a number of factors. It has a particular impact on poor communities, and its eradication has been associated with both food security and poverty alleviation.

In 2011, PPR was demonstrated to be circulating in refugee camps in the southwest of Algeria. Within a year, there was an outbreak of PPR in central Algeria. Molecular typing indicated that this was a lineage IV virus similar to strains in Morocco and Tunisia. In response to this spread a nationwide study was conducted to establish the distribution and risk in the country.

For the study the 48 districts in Algeria were grouped into 5 regions: north-central, north-western, north-eastern, Steppe, and Sahara. The regions were delineated to include a roughly equal number of districts (7-12), but this did not equate to equal distribution of small ruminants. Of the 31 million small ruminants in Algeria, over 50% of them were in the Steppe region.

In total, 150 flocks were sampled, with the number of flocks sampled from a region proportional to the percentage of small ruminants in that region. Flocks and individual animals were tested and randomly allocated. 3336 sheep and 1216 goats were sampled in total. One seropositive animal was considered enough to score the flock as positive for disease. Selected flocks were included in a questionnaire to include individual animal and flock management information.

Consistent with other countries where PPR has been identified, the study showed that the disease was highly prevalent in the small ruminant flocks, with a seroprevalence of 30.45%. This suggests the highly contagious nature of the disease, with the spread driven by free trade and movement from the original index case in the southern borders.

The within-flock prevalence was around 29%, with 75% of the flocks having prevalence equal to, or greater than, 20%. Again, this high prevalence within a flock reinforces the high contagious nature of PPR. The within-flock seroprevalence was significantly higher in mixed flocks than in sheep-only flocks, although the seroprevalance between sheep and goats was similar in the positive-mixed flocks.

The difference in seroprevalance among the regions was not found to be significantly different, although the north-western region, which bordered two endemic countries, was higher than the other regions.

A number of risk factors were considered. Significant risk factors included being in mixed flocks and contact with other flocks. While seropositivity was higher in transhumant flocks when compared to sedentary flocks, this was not significantly different.

 

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