MOBILE PHONE VIDEO MICROSCOPE AUTOMATES DETECTION OF PARASITES IN BLOOD
A research team led by
engineers at the University of California, Berkeley, has developed a new mobile
phone microscope that uses video to automatically detect and quantify infection
by parasitic worms in a drop of blood. This next generation of UC Berkeley's
CellScope technology could help revive efforts to eradicate debilitating
diseases in Africa by providing critical information for health providers in
the field.
"We previously
showed that mobile phones can be used for microscopy, but this is the first
device that combines the imaging technology with hardware and software
automation to create a complete diagnostic solution," said Daniel
Fletcher, associate chair and professor of bioengineering, whose UC Berkeley
lab pioneered the CellScope. "The video CellScope provides accurate, fast
results that enable health workers to make potentially life-saving treatment
decisions in the field."
The UC Berkeley
engineers teamed up with Dr. Thomas Nutman from the National Institute of
Allergy and Infectious Diseases, and collaborators from Cameroon and France to
develop the device. They conducted a pilot study in Cameroon, where health
officials have been battling the filarial, or parasitic worm, diseases
onchocerciasis (river blindness) and lymphatic filariasis.
The video CellScope,
which uses motion instead of molecular markers or fluorescent stains to detect
the movement of worms, was as accurate as conventional screening methods, the
researchers found. The results of the pilot study, performed in Cameroon, are
reported in a paper to be published Wednesday, May 6, in the journal Science
Translational Medicine.
"This research is
addressing neglected tropical diseases," said Fletcher. "It
demonstrates what technology can do to help fill a void for populations that
are suffering from terrible, but treatable diseases."
Battling parasitic
worms
River blindness is
transmitted through the bite of blackflies and is the second leading cause of
infectious blindness worldwide. Lymphatic filariasis, spread by mosquitoes,
leads to elephantiasis, a condition marked by painful, disfiguring swelling in
parts of the body. It is the second leading cause of disability worldwide and,
like river blindness, is highly endemic in certain regions in Africa.
The antiparasitic drug
ivermectin, or IVM, can be used to treat these diseases, but mass public health
campaigns to administer the medication have been stalled because of potentially
fatal side effects for patients co-infected with Loa loa, which
causes loiasis, or African eye worm. When there are high circulating levels of
microscopic Loa loa worms in a patient, treatment with IVM can
lead to brain or other neurologic damage that can be severe or fatal.
The standard method of
screening for levels of Loa loa involves trained technicians
manually counting the worms in a blood smear using conventional laboratory
microscopes, making the process impractical for use in field settings and in
mass campaigns to administer IVM.
The serious side
effects of Loa loa and the difficulty of rapidly quantifying Loa levels
in patients before treatment make it too risky to broadly administer IVM,
representing a major setback in the efforts to eradicate river blindness and
elephantiasis.
Next generation
CellScope uses video, automation
For this latest
generation of the mobile phone microscope, named CellScope Loa, the researchers
paired a smartphone with a 3D-printed plastic base where the sample of blood is
positioned. The base includes LED lights, microcontrollers, gears, circuitry
and a USB port.
Control of the device
is automated through an app the researchers developed for this purpose. With a
single touch of the screen by the healthcare worker, the phone communicates
wirelessly via Bluetooth to controllers in the base to process and analyze the
sample of blood. Gears move the sample in front of the camera, and an algorithm
automatically analyzes the telltale "wriggling" motion of the worms
in video captured by the phone. The worm count is then displayed on the screen.
Fletcher said previous
field tests revealed that automation helped reduce the rate of human error. The
procedure takes about two minutes or less, starting from the time the sample is
inserted to the display of the results. Pricking a finger and loading the blood
onto the capillary adds an additional minute to the time.
The short processing
time allows health workers to quickly determine on site whether it is safe to
administer IVM.
"The availability
of a point-of-care test prior to drug treatment is a major advance in the
control of these debilitating diseases," said aquatic ecologist Vincent
Resh, a professor at UC Berkeley's Department of Environmental Science, Policy
and Management. "The research offering a phone based app is ingenious,
practical and highly needed."
Resh, who is not
involved in the CellScope project, has worked in West Africa for 15 years on
the control of onchocerciasis.
The researchers are
now expanding the study of CellScope Loa to about 40,000 people in Cameroon.
Comments
Post a Comment