Impact of Vaccination on the World Epizootic Situation Plague of Small Ruminants

According to OIE and FAO data in 2009-2019, there have been 2,884 outbreaks of plague of small ruminants (PPR) worldwide, mainly in Africa and Asia. Mortality from this pathology reaches 100 %. The economic damage caused by this disease to animal husbandry consists of a mass mortality, a decrease in the productivity of sick animals and the cost of quarantine measures in a disadvantaged area. Cartographic analysis showed that the highest concentration of PPR outbreaks for the indicated period was observed in five main regions. Northwest Africa (includes Morocco, Algeria and Tunisia); The Black Sea coast of Bulgaria; Eastern coast of the Mediterranean Sea (Israel); People’s Republic of Bangladesh; Southern, Southeastern and Eastern parts of the People’s Republic of China. Outbreaks with the largest number of dead animals were concentrated mainly in Bangladesh and China. Outbreaks with the largest number of dead animals were concentrated mainly in Bangladesh and China, where vaccinations have not been carried out in recent years. The study of the correlation between the PPR incidence rate and the number of animals immunized in the most disadvantaged states found only modest reductions in incidence as a result of vaccination campaigns. Pearson’s correlation coefficient was - 0.13 for Algeria, - 0.19 for Bangladesh and - 0.33 for Israel, which appears to be due to the small scale of vaccination campaigns. The obtained results of the epizootic analysis by PPR indicate insufficient coverage of animals susceptible to the pathogen by vaccination and a greater likelihood of new outbreaks of the disease not only in disadvantaged countries, but also the spread of infection in new territories.

Analysis of environmental factors influencing lumpy skin disease outbreak seasonality and assessment of its spread risk in the Saratovskaya oblast of Russia

Background and Aim

Lumpy skin disease (LSD) is a transboundary viral disease of cattle that causes serious economic losses due to a significant decrease in meat and milk productivity. This study analyzed the influence of natural and anthropogenic environmental factors on LSD spread seasonality and assessed the risk of LSD outbreaks in the Saratovskaya oblast of the Russian Federation.

Materials and Methods

Data on LSD outbreaks and environmental factors during different seasons were collected for the period 2011-2020 in the Balkan Peninsula, Middle East, and Russia. Risk assessment was performed using mathematical modeling with generalized linear regression and maximum entropy.

Results

Fourteen statistically significant environmental factors influencing LSD spread were identified. The analysis of MaxEnt models built using the selected factors showed that the presence of the pathogen is mostly exerted by: the density of susceptible cattle (an increased risk is observed at a density above 10 and 20 heads/10 km2 in winter and autumn, with a permanent risk in spring and summer), the density of water bodies (the risk is increased at any density in winter and autumn, in the range of 13-23.5 m2/km2 in spring, in the ranges of 0-8 and over 14.5 m2/km2 in summer), and average monthly precipitation rate (the most risky are 105-185 mm/month in winter, 35 mm in spring, 15-105 mm in summer, and above 50 mm in autumn).

Conclusion

LSD tends to spread during the warm season. Compared with other test zones, the Saratovskaya oblast has a negligible risk of disease spread (in winter), low risk (in spring), or medium risk (in summer and autumn). The annual risk is low to medium.