Farm Ireland

Tuesday 21 November 2017

Significant risk of spread of animal diseases due to climate change

Ciaran Moran

Ciaran Moran

The introduction, establishment and spread of vector-borne animal diseases represent a significant risk to Ireland; especially as such a high proportion of output is devoted to animal products.

The warning is contained in the Department of Agricultures draft Climate Change Adaptation Plan for the Agriculture and Forest Sector

It says vector-borne diseases rely upon organisms such as mosquitoes, midges, ticks or sandflies that have an active role in the transmission of a pathogen from one host to the other.

Vectors can be introduced to new geographic areas for example by travel of humans and international trade, animal movement, migratory birds, changing agricultural practices, or by the wind.

The climate can play an important role in the lifecycle of diseases and pests that affect livestock, e.g. liverfluke or the introduction of new ‘exotic’ disease not currently found in Ireland.

Susceptibility to disease may increase with the alteration of environmental stresses associated with changing climate patterns.

Each year, the Department advises farmers in relation to the predicted risk of disease caused by liver fluke infection in livestock based on advice received from the Liver Fluke Advisory Group.

DAFM also prepares an annual feed inspection and sampling plan which is heavily influenced by the assessment of risk factors that may impact on animal feed safety.

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It is possible that as temperatures and rainfall increases, the level of mycotoxins occurring in cereal grains could rise. This would impact on cereals both home-grown and imported from Europe.

Key Disease threats

The Bluetongue Virus (BTV)

BTV is an infectious, non-contagious, arthropod borne disease affecting ruminants which is transmitted amongst vertebrate hosts by certain species of Culicoides midges (Mellor et al, 2000).

BTV occurs widely throughout the warmer regions of the world (OIE, 2016). Weather patterns can be critical at several points in the lifecycle of midges and infected midges can be transported by prevailing winds when certain climatic and vector factors are conducive.

DAFM commissioned a three-year vector monitoring programme to determine seasonal vector activity. This was carried out in conjunction with National University Ireland, Galway from 2007 to 2010.

DAFM regularly updates its contingency arrangements and plans to deal with a potential outbreak and continues to monitor developments.

DAFM also carried out a risk assessment on the introduction and spread of BTV in Ireland.

The Schmallenberg Virus (SBV)

SBV affects ruminant animals and was first detected in Ireland in October 2012. It is primarily spread by biting insects, such as the Culicoides midge.

It was expected that once the virus was detected here, it would spread rapidly. The warm and mostly dry conditions of summer 2013 were conducive to the spread of SBV. However, SBV did not spread, possibly due to the low temperatures of winter 2012 which may have reduced the number of midges.

DAFM regional veterinary laboratories, in conjunction with Sheep Ireland, district veterinary offices and a number of private veterinary practitioners, targeted sheep flocks which were blood sampled and tested for the presence of antibodies at six weekly intervals over the summer of 2013. Regular advice and technical updates were provided by DAFM.

Lumpy Skin Disease (LSD)

Lumpy skin disease (LSD) is a viral disease of cattle caused by a pox virus. It causes fever, nodules on the skin and may result in severe losses. LSD does not affect humans.

It is believed to be primarily transmitted by biting and blood feeding insects as well as other arthropods.

From 1929 when the disease was first recorded, until 1989, LSD was confined to Sub-Saharan Africa. In subsequent years, multiple countries in the Middle-East have reported LSD. Turkey has been reporting LSD outbreaks since 2013, and the disease spread from here to Azerbaijan (2014) and Greece (2015). Since then LSD has spread steadily through several Balkan countries during 2016.

DAFM is monitoring developments and updating contingency arrangements accordingly.

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