Methods and devices for real-time diagnostic testing (RDT) for ebola and other infectious diseases
Methods, devices, systems, and kits for use in detecting and measuring infectious diseases are provided. In particular embodiments, methods, devices, systems, and kits for detecting and measuring Ebola virus, including Ebola Zaire strain virus, are provided. Devices and systems may be used within regions suffering from Ebola or other infections, providing local, rapid, and effective diagnosis of infectious diseases such as Ebola, improving treatment and reducing or preventing spread of such infectious diseases.
1. A method for detecting the presence of a virus in a blood sample obtained from a subject, or of detecting prior contact by the subject with said virus, the virus having viral nucleic acid, comprising:
providing a cartridge with reagents for a nucleic acid assay, an assay for detecting antibodies, and at least two electrolyte assays;
inserting said cartridge into a sample processing instrument for:
i) performing said nucleic acid assay for detecting the presence of, or measuring the amount of, the virus in said blood sample obtained from a subject suspected of suffering from the viral disease, the assay comprising contacting a primer complementary to at least a portion of said viral nucleic acid with said sample;
ii) performing said assay for detecting the presence of, or measuring the amount of, antibodies to the virus, in a sample obtained from a subject suspected of suffering from the viral disease, the assay comprising contacting a viral antigen with said sample; and
iii) performing said electrolyte assays for measuring the amount of sodium and for measuring the amount of potassium in the blood sample;
wherein the presence of the virus is detected in the occurrence of detection of viral nucleic acid, or prior contact by the subject with the virus is detected if antibodies to the virus are detected in the sample.
2. The method of claim 1 , wherein said blood sample is a fingerstick blood sample.
3. The method of claim 1 , wherein said nucleic acid assay comprises an isothermal nucleic acid assay.
4. The method of claim 1 , wherein said assay for detecting the presence of, or measuring the amount of, antibodies to the virus, comprises IgM and IgG assays for antibodies to the virus.
5. The method of claim 1 , wherein said nucleic acid assay provides results within a short time of less than about 1 hour and said assay for detecting the presence of, or measuring the amount of, antibodies to the virus provides results within a short time of less than about 1 hour.
6. The method of claim 1 , wherein said blood sample comprises a sample of EDTA-anti-coagulated whole blood.
7. The method of claim 1 , wherein said blood sample comprises a sample of heparin-anti-coagulated plasma.
8. An automatic sample analysis device configured to perform the following method at a point of service location:
using a cartridge with reagents for a nucleic acid assay, an assay for detecting antibodies, and at least two electrolyte assays;
inserting said cartridge into the automatic sample analysis device for:
i) performing a nucleic acid assay for detecting the presence of, or measuring the amount of, the virus in said blood sample obtained from a subject suspected of suffering from the viral disease, the assay comprising contacting a primer complementary to at least a portion of said viral nucleic acid with said sample;
ii) performing an assay for detecting the presence of, or measuring the amount of, antibodies to the virus, in a sample obtained from a subject suspected of suffering from the viral disease, the assay comprising contacting a viral antigen with said sample; and
iii) performing electrolyte assays for measuring the amount of sodium and for measuring the amount of potassium in the blood sample;
wherein the presence of the virus is detected in the occurrence of detection of viral nucleic acid, or prior contact by the subject with the virus is detected if antibodies to the virus are detected in the sample.
9. The automatic sample analysis system of claim 8 , further comprising a cartridge containing reagents for performing the methods of claim 8 .
10. The method of claim 1 , wherein steps i to iii are performed using the sample processing instrument using the cartridge comprising:
a first polynucleotide primer and a second polynucleotide primer, wherein the first primer and the second primer are complementary to a nucleotide sequence from the Ebola virus, or to a complementary sequence thereof;
an anti-human IgM antibody;
an anti-human IgG antibody;
an isolated Ebola polypeptide antigen; and
an isolated DNA polymerase having strand displacement activity.
11. The cartridge of claim 10 , wherein the DNA polymerase is Bstl.
12. The method of claim 10 , wherein at least one of the anti-human IgM antibody of the anti-human IgG antibody is immobilized on a solid surface.
13. The method of claim 10 , wherein the cartridge further comprises reagents for the detection of one or both of sodium or potassium ions.
14. The method of claim 13 , wherein the cartridge comprises β-galactosidase for the detection of sodium ions.
15. The method of claim 13 , wherein the cartridge comprises sodium tetraphenylborate for the detection of potassium ions.
16. The method of claim 13 , wherein the cartridge comprises β-galactosidase and sodium tetraphenylborate.
17. The method of claim 10 , wherein the cartridge further comprises reagents for the detection of one or both of iron or hemoglobin.
18. The method of claim 10 , wherein the cartridge further comprises a reagent to render a virus non-infectious.
19. The method of claim 10 , wherein the cartridge further comprises an anti-Ebola virus antigen antibody.
20. A method for detecting the presence of a virus in a blood sample obtained from a subject, or of detecting prior contact by the subject with said virus, the virus having viral nucleic acid, comprising:
providing a cartridge with reagents for a nucleic acid assay, an assay for detecting antibodies, and at least two electrolyte assays;
inserting said cartridge into a sample processing instrument for:
i) performing said nucleic acid assay for detecting the presence of, or measuring the amount of, the virus in said blood sample obtained from a subject suspected of suffering from the viral disease, the assay comprising contacting a primer complementary to at least a portion of said viral nucleic acid with said sample;
ii) performing said assay for detecting the presence of, or measuring the amount of, antibodies to the virus, in a sample obtained from a subject suspected of suffering from the viral disease, the assay comprising contacting a viral antigen with said sample; and
iii) performing said electrolyte assays for measuring the amount of sodium and for measuring the amount of potassium in the blood sample;
wherein the presence of the virus is detected in the occurrence of detection of viral nucleic acid, or prior contact by the subject with the virus is detected if antibodies to the virus are detected in the sample;
wherein said blood sample is a small volume blood sample having a volume of less than about 250 microliters (μL).