Practical and effective diagnosis of animal anthrax in endemic low-resource settings

by Olubunmi R. Aminu, Tiziana Lembo, Ruth N. Zadoks, Roman Biek, Suzanna Lewis, Ireen Kiwelu, Blandina T. Mmbaga, Deogratius Mshanga, Gabriel Shirima, Matt Denwood, Taya L. Forde Anthrax threatens human and animal health, and people’s livelihoods in many rural communities in Africa and Asia. In these areas, anthrax surveillance is challenged by a lack of tools for on-site detection. Furthermore, cultural practices and infrastructure may affect sample availability and qua lity. Practical yet accurate diagnostic solutions are greatly needed to quantify anthrax impacts. We validated microscopic and molecular methods for the detection ofBacillus anthracis in field-collected blood smears and identified alternative samples suitable for anthrax confirmation in the absence of blood smears. We investigated livestock mortalities suspected to be caused by anthrax in northern Tanzania. Field-prepared blood smears (n = 152) were tested by microscopy using four staining techniques as well as polymerase chain reaction (PCR) followed by Bayesian latent class analysis. Median sensitivity (91%, CI95% [84 –96%]) and specificity (99%, CI95% [96 –100%]) of microscopy using azure B were comparable to those of the recommended standard, polychrome methylene blue, PMB (92%, CI95% [84 –97%] and 98%, CI95% [95 –100%], respectively), but azure B is more available and convenient. Other commonly-used stains performed poorly. Blood smears could be obtained for
Source: PLoS Neglected Tropical Diseases - Category: Tropical Medicine Authors: Source Type: research