In Part I we introduced the notion of 'vulnerability' and its relations to a set of processes involving access to resources in the maintenance of livelihoods. In Chapter 4 (in Part II) we began to apply these concepts, and suggested that famine is seldom caused by extreme climatic conditions (such as drought) alone, and that a severe decline in food consumption which might be expected to result from a drought may either not occur at all, or may not be the prime cause of a disastrous famine. What is of prime importance is people's vulnerability, brought about by long-term or sudden disruptions to their access to resources of all kinds, both material and non-material, and people's ability to use them in the successful pursuit of a livelihood. In a similar way, biological hazards may be both a trigger to a disaster and exacerbate its consequences, or follow on from other socio-economic root causes and unsafe conditions, once the disaster process is under way.
The present chapter focuses on hazards that originate in the life processes and conditions of other living things that affect humans and their livelihoods and assets. On the macro-scale, humans and their built environments are often surrounded by vegetation. Forests, for example, can provide protection from high winds and a reserve of survival food as a buffer against famine. However, they can also burn catastrophically. 1 Macrofauna (organisms visible to the naked eye) can be beneficial to humans, but some animals, such as rats, some birds and also insects, can damage crops or stored food. On the microbiological scale, minute organisms can also benefit or harm humans with 'biological disasters' that can affect both people (epidemics) and their animals or crops (epizootics, explosive plant disease and pest infestations).
In Part I of this book we emphasised how the conditions of daily life, to a large extent, account for the vulnerability of individuals, households and social groups. Daily life is, above all, biological, so it is important to recall this theme of the 'everyday' or the 'normal' (Lefebvre 1991; Wisner 1993;