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In Kazakhstan, plague outbreaks occur when its main host, the great gerbil, exceeds an abundance threshold. These live in family groups in burrows, which can be mapped using remote sensing. Occupancy (percentage of burrows occupied) is a good proxy for abundance and hence the possibility of an outbreak. Here we use time series of satellite images to estimate occupancy remotely. In April and September 2013, 872 burrows were identified in the field as either occupied or empty. For satellite images acquired between April and August, ‘burrow objects’ were identified and matched to the field burrows. The burrow objects were represented by 25 different polygon types, then classified (using a majority vote from 10 Random Forests) as occupied or empty, using Normalized Difference Vegetation Indices (NDVI) calculated for all images. Throughout the season NDVI values were higher for empty than for occupied burrows. Occupancy status of individual burrows that were continuously occupied or empty, was classified with producer’s and user’s accuracy values of 63 and 64% for the optimum polygon. Occupancy level was predicted very well and differed 2% from the observed occupancy. This establishes firmly the principle that occupancy can be estimated using satellite images with the potential to predict plague outbreaks over extensive areas with much greater ease and accuracy than previously. [ABSTRACT FROM AUTHOR]

Abstract: Objective: To assess the presence and identity of Bartonella species in a pool of human blood samples from DRC Congo. Methods: Blood (±120μL) was collected anonymously from Congolese patients and placed on calibrated filter papers. Bartonella serology determination was performed using an indirect immunofluorescence assay (IFA) against six specific Bartonella antigens and Coxiella burnetii (C. burnetii) antigen. The end cut-off value for Bartonella sp. was a titre greater than 1:200. Results: None of the patients was positive for Bartonella elizabethae, Bartonella vinsonii subsp. vinsonii or Bartonella vinsonii subsp. arupensis nor for C. burnetti, but 4.5% of the 155 samples were positive for either Bartonella henselae, Bartonella quintana, or Bartonella clarridgeiae. Conclusions: This preliminary study presents the first report of Bartonella species in the DR Congo and the first report of antibodies to Bartonella clarridgeiae in an African human population. Although few experimental trials have established the link between fleas and Bartonella transmission, the repeated detection of similar Bartonella species in fleas and humans in several countries suggests that Bartonellosis could be another flea-borne disease which specific reservoirs are still unknown. [Copyright &y& Elsevier]