Factors affecting the transmission of Weil's disease in the mammalian host, with especial reference to epithelial penetration

Abstract

The genus Leptospira is described in terms of taxonomy, morphology and epidemiology. The dose dependent effects of serotype icterohaemorrhagiae on the hamster are described, but are found too variable for use in estimating numbers of organisms invading the animal during subsequent experiments. Two techniques were used to demonstrate hyaluronidase production. No such activity was found. The permeability of various body surfaces to penetration was examined in vivo by infection. Many epithelia allowed the organism to pass, but it is suggested that microlesions may be important. Further experiments attempting to demonstrate penetration microscopically in vitro and in vivo using silver stain were not successful. The use of immunohistology demonstrated penetrating leptospires. Invasion was only seen in relation to existing lesions, reinforcing the earlier findings. Protective properties of various membranes are discussed in relation to the invasive properties of the leptospire. The effect of fluids from the mammalian body on the viability of leptospires is examined in relation to pH, osmotic pressure and other factors. pH removed from neutrality is demonstrated to be harmful, the effect is reinforced in the presence of high osmotic pressure. It is shown that other damage producing factors are present and these are discussed. The motility of leptospires is described for free fluid, semi-solids and in relation to surfaces. These findings are discussed in relation to the transmission of leptospires under natural conditions. The need for caution when applying experimental findings to natural conditions is stated and explained.