In this review, we propose two hypotheses for the mechanisms by which land use change can lead to viral emergence: firstly, by perturbing disease dynamics in multihost disease systems via impacts on cross-species transmission rates (the 'perturbation' hypothesis); and secondly, by allowing exposure of novel hosts to a rich pool of pathogen diversity (the 'pathogen pool' hypothesis).
In addition, recent studies highlighted their role in the pooling of infectious pathogens and other antigens to the spleen.
Each pathogen environment consists of a pool of n p pathogens, each of them characterized by two parameters.
Although the microbes allowed in SPF facilities are strictly regulated, each mouse house is home to a distinct pool of microorganisms, including a variety of pathogens that come from contaminations or adventitious infections (Jacoby and Lindsey, 1998; Pritchett-Corning et al., 2009; Taylor et al., 2007).
The reemergence of highly pathogenic avian influenza A(H5N1) virus in 2004, the isolation of novel bat-associated reoviruses from humans in Malaysia in 2006, and the discovery of a novel tick-borne bunyavirus associated with fever and thrombocytopenia in rural farmers in China in 2009 attest to the existence of a pool of potential zoonotic pathogens in East and Southeast Asia (Table) (8, 9, 12 ).
Alongside this existing pool of known human pathogens, a large and diverse population of mammalian wildlife species and domestic livestock reside in the region, acting as reservoirs or amplifying species from which new infectious diseases of humans might emerge (3, 4 ).
At large institutions, there is often an enormous pool of microbiological data, yielding more accurate estimations on the prevalence of pathogens, but a manually conducted review is unattainable.
The contribution of CD4+ vs CD8+ effector memory T cells in the migratory and resident pools of lymphocytes specific to a given pathogen has been investigated in skin infection but is unclear in the CNS [ 6].
Military use of pathogens is as old as human conflict.
The results show that the influence of pathogens has been underestimated, with 89.3% of childhood diarrhoea cases caused by pathogens.
