Seroprevalence and risk factors for infection with Bartonella bacilliformis in Loja province, Ecuador

Abstract

The seroprevalence and epidemiology of Bartonella bacilliformis infection in the Andean highlands of Ecuador is largely unknown. We conducted a sero-epidemiologic survey of 319 healthy children aged 1-15 years living in six rural, mountain communities in Loja Province, Ecuador. Blood was collected by finger stick onto filter paper and dried, and the eluted sera analyzed for antibodies to B. bacilliformis by rPap31 ELISA. Demographic, entomologic, and household variables were assessed to investigate associated risk factors for antibody seropositivity to B. bacilliformis. Seroprevalence of 28% was found among children in the study communities. Increased risk of seropositivity was associated with the presence of lumber piles near houses. Decreased risk of seropositivity was observed with the presence of animal waste and incremental 100 meter increases in elevation. Although investigation of clinical cases of Carrion's disease was not within the scope of this study, our serology data suggest that infection of children with B. bacilliformis is prevalent in this region of Ecuador and is largely unrecognized and undiagnosed. This study highlights the need to further investigate the prevalence, pathogenesis, epidemiology, and disease impact of this pathogen in Ecuador.

Fig. 1

Age curve of seropositivity showing the percentage of children at each age from total children in all six study communities in Loja Province compared to the percentage of seropositive children at each age. The left axis corresponds to the line graph denoting the percentage of children at each age. The right axis corresponds to the bar graph denoting the percentage of children at each age that are seropositive

Fig. 2. Map of Ecuador (inset) with Loja province shaded.

The six study communities are identified in the large map of Loja province. Also shown is the provincial capital city of Loja and major communities of Catacocha (Paltas County) and Cariamanga (Calvas County). WGS84 coordinates for each community are as follows: Chirimoyos (04.12972°S, 79.5456°W), Vega del Carmen (04.10610°S, 79.59012°W), Jacapo (04.36621°S, 79.4162°W), Usaime (04.46035°S, 79.54414°W), Santa Rosa (04.3960°S, 79.41861°W, and Galapagos (04.35233°S, 79.4344°W)