title: Quantitative evaluation of a handheld light microscope for field diagnosis of soil-transmitted helminth infection.
abstract: We evaluated the Newton Nm1, a commercially available handheld light microscope and compared it with conventional light microscopy for the diagnosis of soil-transmitted helminth infections. A total of 91 Kato-Katz thick smears were examined by experienced microscopists and helminth eggs were counted and expressed as eggs per gram of stool (EPG). Mean egg counts were significantly higher with the conventional light microscope (5,190 EPG versus 2,386 EPG for Ascaris lumbricoides; 826 versus 456 for Trichuris trichiura; both P < 0.05). Using regression coefficients and accounting for intensity of infection, we found that the agreement between the two devices was excellent for both species (κ = 0.90, 95% confidence interval = 0.82-0.99 for A. lumbricoides and κ = 0.96, 95% CI = 0.91-1.00 for T. trichiura). The Newton Nm1 microscope may be a useful tool for the detection and quantification of soil-transmitted helminth infection in clinical, epidemiologic, and public health settings.
authors.affiliation: Divisions of Internal Medicine and Infectious Diseases, Toronto General Hospital, Toronto, Ontario, Canada; University of Toronto, Toronto, Ontario, Canada; Division of Infectious Diseases and Geographic Medicine, Stanford University School of Medicine, Stanford, California; Department of Medical Parasitology and Infection Biology, and Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland; University of Basel, Basel, Switzerland; Public Health Laboratory Ivo de Carneri, Chake, Chake, Pemba Island, Tanzania; Department of Parasitology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom isaac.bogoch@uhn.ca.
authors.forename: Isaac I
authors.initials: II
authors.lastname: Bogoch
authors.affiliation: Divisions of Internal Medicine and Infectious Diseases, Toronto General Hospital, Toronto, Ontario, Canada; University of Toronto, Toronto, Ontario, Canada; Division of Infectious Diseases and Geographic Medicine, Stanford University School of Medicine, Stanford, California; Department of Medical Parasitology and Infection Biology, and Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland; University of Basel, Basel, Switzerland; Public Health Laboratory Ivo de Carneri, Chake, Chake, Pemba Island, Tanzania; Department of Parasitology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom.
authors.forename: Jason R
authors.initials: JR
authors.lastname: Andrews
authors.affiliation: Divisions of Internal Medicine and Infectious Diseases, Toronto General Hospital, Toronto, Ontario, Canada; University of Toronto, Toronto, Ontario, Canada; Division of Infectious Diseases and Geographic Medicine, Stanford University School of Medicine, Stanford, California; Department of Medical Parasitology and Infection Biology, and Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland; University of Basel, Basel, Switzerland; Public Health Laboratory Ivo de Carneri, Chake, Chake, Pemba Island, Tanzania; Department of Parasitology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom.
authors.forename: Benjamin
authors.initials: B
authors.lastname: Speich
authors.affiliation: Divisions of Internal Medicine and Infectious Diseases, Toronto General Hospital, Toronto, Ontario, Canada; University of Toronto, Toronto, Ontario, Canada; Division of Infectious Diseases and Geographic Medicine, Stanford University School of Medicine, Stanford, California; Department of Medical Parasitology and Infection Biology, and Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland; University of Basel, Basel, Switzerland; Public Health Laboratory Ivo de Carneri, Chake, Chake, Pemba Island, Tanzania; Department of Parasitology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom.
authors.forename: Shaali M
authors.initials: SM
authors.lastname: Ame
authors.affiliation: Divisions of Internal Medicine and Infectious Diseases, Toronto General Hospital, Toronto, Ontario, Canada; University of Toronto, Toronto, Ontario, Canada; Division of Infectious Diseases and Geographic Medicine, Stanford University School of Medicine, Stanford, California; Department of Medical Parasitology and Infection Biology, and Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland; University of Basel, Basel, Switzerland; Public Health Laboratory Ivo de Carneri, Chake, Chake, Pemba Island, Tanzania; Department of Parasitology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom.
authors.forename: Said M
authors.initials: SM
authors.lastname: Ali
authors.affiliation: Divisions of Internal Medicine and Infectious Diseases, Toronto General Hospital, Toronto, Ontario, Canada; University of Toronto, Toronto, Ontario, Canada; Division of Infectious Diseases and Geographic Medicine, Stanford University School of Medicine, Stanford, California; Department of Medical Parasitology and Infection Biology, and Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland; University of Basel, Basel, Switzerland; Public Health Laboratory Ivo de Carneri, Chake, Chake, Pemba Island, Tanzania; Department of Parasitology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom.
authors.forename: J Russell
authors.initials: JR
authors.lastname: Stothard
authors.affiliation: Divisions of Internal Medicine and Infectious Diseases, Toronto General Hospital, Toronto, Ontario, Canada; University of Toronto, Toronto, Ontario, Canada; Division of Infectious Diseases and Geographic Medicine, Stanford University School of Medicine, Stanford, California; Department of Medical Parasitology and Infection Biology, and Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland; University of Basel, Basel, Switzerland; Public Health Laboratory Ivo de Carneri, Chake, Chake, Pemba Island, Tanzania; Department of Parasitology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom.
authors.forename: Jürg
authors.initials: J
authors.lastname: Utzinger
authors.affiliation: Divisions of Internal Medicine and Infectious Diseases, Toronto General Hospital, Toronto, Ontario, Canada; University of Toronto, Toronto, Ontario, Canada; Division of Infectious Diseases and Geographic Medicine, Stanford University School of Medicine, Stanford, California; Department of Medical Parasitology and Infection Biology, and Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland; University of Basel, Basel, Switzerland; Public Health Laboratory Ivo de Carneri, Chake, Chake, Pemba Island, Tanzania; Department of Parasitology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom.
authors.forename: Jennifer
authors.initials: J
authors.lastname: Keiser
mesh_terms: D000818:Animals; D006373:Helminthiasis / Q000175:diagnosis* / Q000635:transmission; D006801:Humans; D008853:Microscopy / Q000295:instrumentation*; D010270:Parasite Egg Count; D012987:Soil / Q000469:parasitology*
chemical_list: D012987:Soil