detecting the known- latest technologies in pen-side tests › eng › biothreat2015 ›...
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Detecting the known- latest technologies in pen-side tests…a reliable test even when it is raining and dark?
Kath Webster & Andrew Soldan
Constraints- Resource poor?• Not much money
– Low input systems eg sheep in Australia or poultry in Malawi• No/poor facilities
– Heat, light, power, shelter• Little expertise
– Laboratory tech, service engineers, result interpretation skills• Poor supply/communication lines
– Cold chain + storage, no transport, result communication • Inability to take sample
– Blood, faeces, • Very little time
– Other work to do – stopping to run a test does not fit into work flow
Other drivers to move test from the lab
• No existing test• Human safety• Better customer service• Lower overall cost• Need for rapid results• Sample deterioration
Personal case studies
Sheep with mouth lesions during FMD outbreak in UK 2001
• Flock of 30 – not quite pets but close!
• Lesions in mouth of three• Two miles from infected
farm but not contiguous• FMD could not be ruled out• Slaughtered• Compensation ~US$2,000
Dog with starey eyes in Chitipa Northern Malawi
• One person bitten• Whole village concerned• Post exposure treatment second
biggest drug cost to Malawi health system after malaria treatment
• No holding facilities• 8 hrs drive to central lab
Horse with nasal discharge in Devon, UK
• DIY livery yard with ~30 horses
• New horse with runny nose• Differential – Strangles (S
equi equi)• Other owners saying horse
should be moved out of yard• Swab taken, horse isolated
and result in 48hrs
What is an ideal test for such situations
• Cheap- <$1 to $20 for test. No equipment or very cheap equipment - <$500?
• Robust in range of situations, ideally does not need external power source
• Easy to use - 10 min familiarisation with the instructions, result interpretation easy
• Little/no sample prep, droppers not pipettes• Temperature stable in storage• Rapid result - <30 min• Accurate enough to inform a decision
Yes• Rose Bengal Plate test• Latex agglutination tests• Lateral flow devices• SNAP tests• Urine dip sticks• Glucometer
Do such tests exist?
Pregnancy test
• Gold standard for point of care testing• Untrained user• Rapid – 1 to 3 minutes• >99% accurate 2w after conception• Informative• Cheap ~ $4 each
12
Some interesting technologies
• More of what we have already – LFD, SNAP etc• Miniaturised/simplified PCR based• Array based• Isothermal amplification based• Paper based• Biological sensor based• Sequencing
Miniaturised/simplified PCR based
Miniaturised/simplified PCR based
Array based
Isothermal amplification based
Isothermal amplification based
Isothermal amplification based
Paper based
Biological sensor based
Sequencing
Technology is great but ………
• Is it cheap enough? – both instrument and test cost
• Does the operator have the right skills?– To select test– To do test– To take sample– To interpret result
• Is it robust enough?• Is it accurate enough?
Where will the test be done?
• Pen side• In the kitchen/farm office• At a forward operating base in an outbreak• In a laboratory
– Regional lab– Local lab– Central lab
Conclusions
• Confusion between the need for rapid results and the need for on farm testing – technical solutions may be different
• Technology is advancing rapidly• New tests will appear • Molecular – no/little equipment costs• These tests will require little training to use• There will be a move from central labs to local labs –
Abattoir, LDCCs, practice labs, private labs etc• Advantages for the developing worldThe major move is going to be from central lab to local lab – not onto farm