This themed issue of Philosophical Transactions B, provides an overview of some of the issues relating to infectious diseases of livestock.

At the beginning of the 21st Century, the world is faced with a changing landscape of infectious diseases that affect man and animals. Most livestock pathogens that emerge and re-emerge are capable of being transmitted to man and an increasing number are distributed by insect vectors. Globalisation defines the world of pathogens and the recent emergence and spread of swine flu provides a topical illustration of the threats presented by zoonotic viruses that can be moved rapidly around the world by the occupants of our ‘global village’. Whilst distribution via air transport represents an extreme, the transmission of pathogens by insect vectors is increasingly linked to the effects climate change and new vector-borne diseases, such as bluetongue, are now occurring for the first time in Northern Europe.

However, old and persistent diseases remain in most parts of the world must be dealt with. Some, such as foot and mouth disease, present significant ongoing restrictions to national and international trade and may have devastating financial impacts when they are introduced in to FMD-free areas.

The future looks to be much, much more of the same. The scientific community will need to be fleet-of-foot to deal with some unexpected disease threats and the world of zoonotic infections will drive the animal and human disease research specialists to work closer together.

A ‘One Medicine’ way of working will be increasingly necessary to optimise control of disease at the livestock-man interface and all major livestock diseases will need to be considered for their potential to interrupt or damage the pipeline of food supplies – especially if effective control is lost.

This special issue includes articles by ILRI scientists Brian Perry and Delia Grace and another by  Solenne Costard et al. They describe the impacts of livestock diseases and their control on growth and development processes that are ‘pro-poor’.

Taking a value-chain approach that includes keepers, users and eaters of livestock, they identify diseases that are road blocks on ‘three livestock pathways out of poverty’. They discuss livestock impacts on poverty reduction and review attempts to prioritize the livestock diseases relevant to the poor. They note that a high impact of a disease does not guarantee high benefits from its control and recommend taking other factors into consideration, including technical feasibility and political desirability.

They conclude their paper by considering how we might better understand and exploit the roles of livestock and improved animal health by posing three speculative questions on the impact of livestock diseases and their control on global poverty:
(1) How can understanding livestock and poverty links help disease control?
(2) If global poverty reduction were the aim of a livestock disease control program, how would that program differ from our current model?
(3) How much of the impact of livestock diseases on poverty is due to disease control policies rather than the diseases themselves?