Phytopathogenic bacteria generally have limited host ranges, often confined to members of a single plant species or genus. This appears to result from negative factors restricting the host range ra.ther than from positive factors which allow the pathogen to infect its hosts. These negative factors are avirulence genes present in the pathogen, which interact with matching resistance genes in the...

Disease can be an important driver of host population dynamics and epizootics can cause severe host population declines. Batrachochytrium dendrobatidis (Bd), the pathogen causing amphibian chytridiomycosis, may occur epizootically or enzootically and can harm amphibian populations in many ways. While effects of Bd epizootics are well documented, the effects of enzootic Bd have rarely been descr...

The objective of this study was to estimate heritabilities for and genetic correlations among different pathogen-specific mastitis traits. The traits were unspecific mastitis, which is all mastitis treatments regardless of the causative pathogen as well as mastitis caused by Streptococcus dysgalactiae, Escherichia coli, coagulase-negative staphylococci (CNS), Staphylococcus aureus and Streptoco...

In a wild plant-pathogen system, host resistance and pathogen virulence varied markedly among local populations. Broadly virulent pathogens occurred more frequently in highly resistant host populations, whereas avirulent pathogens dominated susceptible populations. Experimental inoculations indicated a negative trade-off between spore production and virulence. The nonrandom spatial distribution...

Oral administration of polymyxin to specific-pathogen-free C3H/Law mice which with previously contaminated with gram-negative bacteria resulted in complete suppression of cecal gram-negative bacteria. Suppression of cecal gram-negative bacteria was accompanied by reduction of the cecal endotoxin concentration from 10 to 1 microgram/g of cecal content as measured with a microtechnique for the Li...