3.4.4 Association of abundance of flea species with other factors
We found that abundance of flea species was statistically significant associated with type of habitat (χ2 (9) = 41.701,p< .001), season (χ2 (3) = 17.839,p< .001), rodent species (χ2 (15) = 134.35,p< .001) and rodent sex (χ2 (3) = 10.543,p= .014), but was not statistically significant associated with plague locations (plague and non-plague foci) (χ2 (3) = 2.4006,p= 0.49). Balloon chart was plotted to describe this relationship by using Pearson residuals (standardized residuals) of all level of each factor. The high value of Pearson residual was described with the big and bright red balloon in a gradient of size and color from dark to pale red suggesting particular level of factor had strong association with abundance of particular flea specie and a gradient of small balloons of white to bright blue suggesting weak or insignificant association of abundance of particular flea specie (fig 3) .
Fig3 . Balloon chart showing association of abundance of fleas species with other factors; the abbreviations Cteno=Ctenophthalmus spp , Dino= Dinopsyllus lypusus . X.br=Xenopsylla brasiliensis and X.cheo= Xenopsylla cheopis .