Authors

H Sjöberg¹; A E Marriott¹; A Steven¹; D Cook¹; M J Taylor¹; J D Turner¹;  ¹ Liverpool School of Tropical Medicine

Discussion

Ultrasonography (USG) has been successfully used in placebo-controlled clinical trials to evaluate macrofilaricidal drug efficacy in filarial infection. Here we describe the use of a portable USG machine (SonoSite MTurbo) to detect ‘filarial dance sign’ (FDS) in preclinical Brugia malayi rodent drug screening models. Defined numbers of B. malayi adults were lanted into the peritoneum or, alternatively, B. malayi adult burdens were established from a unit intraperitoneal inoculum of infectious stage larvae within inbred Severe-Combined ImmunoDeficient mice or outbred Meriones unguiculatus (Mongolian) gerbils. USG successfully detected FDS of mixed sex or single sex adult worm burdens to a sensitivity degree of 1 female/2 male worms. USG could also be applied to semi-quantify worm loads based on strength and multiplicity of FDS signal in different peritoneal anatomical  locations. In both non-blinded and blinded preclinical drug studies, USG detection of FDS has been used to accurately predict macrofilaricidal outcome. This technique could be highly beneficial in refining and reducing the number of animals used in drug screens, accelerating preclinical macrofilaricidal drugs by rapidly detecting efficacy in longitudinal exam of the same study group without invasive surrogate filarial viability sampling.