A mathematical epidemiological model of gram-negativeBartonellabacteria: does differential ectoparasite load fully explain the differences in infection prevalence ofRattus rattusandRattus norvegicus?

Abstract

We postulate that the large difference in infection prevalence, 24% versus 5%, in R. norvegicus and R. rattus, respectively, between these two co-occurring host species may be due to differences in ectoparasite and potential vector infestation rates. A compartmental model, representative of an infectious system containing these two Rattus species and two ectoparasite vectors, was constructed and the coefficients of the forces of infection determined mathematically. The maximum difference obtained by the model in the prevalence of Bartonella in the two Rattus species amounts to 4.6%, compared to the observed mean difference of 19%. Results suggest the observed higher Bartonella infection prevalence in Rattus norvegicus compared to Rattus rattus, cannot be explained solely by higher ectoparasite load. The model also highlights the need for more detailed biological research on Bartonella infections in Rattus and the importance of the flea vector in the spread of this disease.

BartonellaInfection in Rodents and Their Flea Ectoparasites: An Overview

“…For instance, it was noticed that the higher flea abundance on wild rodents from Poland in 2006 correlated with a higher overall Bartonella infection compared to 2004 (Welc-Faleciak et al 2010). On the contrary, differences in infestation rates of R. rattus and R. norvegicus from South Africa did not explain the observed difference in Bartonella infection prevalence (24% versus 5%) between these rat species (Brettschneider et al 2012a). The Bartonella sp.…”

Bartonella Bacteria in Urban Rats: A Movement From the Jungles of Southeast Asia to Metropoles Around the Globe

“…A significant difference of Bartonella prevalence was observed between two rat species (24% in R. norvegicus vs. 5% in R. rattus) in South Africa (Brettschneider et al, 2012). The authors of this study proposed a mathematical model explaining that the difference between these two co-occurring rat species might be due to the observed differences in flea infestation rates between these species.…”

Path analyses of cross-sectional and longitudinal data suggest that variability in natural communities of blood-associated parasites is derived from host characteristics and not interspecific interactions

“…This is because fleas are considered as key players in the Bartonella cycle based on their dominancy in flea microbiomes [ 64 , 65 , 82 ] and conclusive experimental evidence of efficient flea-borne transmission (e.g., [ 83 – 85 ]). In some other observational studies, the correlations between flea abundance and Bartonella occurrence were weak or also absent [ 49 , 66 , 86 ]. The reason that direct positive effects between Bartonella and fleas may be obscured in observational data could be attributed to the overall high prevalence of Bartonella and/or direct interaction of Bartonella with other bacteria that are less dependent on fleas for their transmission ( Mycoplasma in our case).…”