Peptides, devices, and methods for the detection of

1. A population of synthetic isolated peptides comprising three or more different peptides, wherein each peptide in the population comprises the sequence of:

S-X 2 -K-E-X 5 -K-Q-X 8 -T-X 10 -X 11 -X 12 -X 13 -G-L-K-Q-X 18 -W-X 20 -G-X 22 -X 23 -X 24 -X 25 -X 26 -G-G-G-G-G-N-F-S-A-K-E-E-X 39 -A-E-T-R-X 44 -T-F-G-L-X 49 -K-Q-Y-D-G-A-X 56 -I-X 58 -E-N-Q-V-Q-N-K-F-T-I-S-N-C (SEQ ID NO: 72) or fragment thereof,

wherein X 2 is an amino acid selected from the group consisting of A and V, X 5 is an amino acid selected from the group consisting of E and D, X 8 is an amino acid selected from the group consisting of T and P, X 10 is an amino acid selected from the group consisting of T and V, X 11 is an amino acid selected from the group consisting of G and A, X 12 is an amino acid selected from the group consisting of L and V, X 13 is an amino acid selected from the group consisting of Y and F, X 18 is an amino acid selected from the group consisting of D and N, X 20 is an amino acid selected from the group consisting of D and N, X 22 is an amino acid selected from the group consisting of S and V, X 23 is an amino acid selected from the group consisting of A, S, and T, X 24 is an amino acid selected from the group consisting of A and I, X 25 is an amino acid selected from the group consisting of T and P, X 26 is an amino acid selected from the group consisting of S, N, and K, X 39 is any amino acid, X 44 is any amino acid, X 49 is any amino acid, X 56 is any amino acid, and X 58 is any amino acid, and

wherein said fragment comprises at least 35 contiguous amino acids from SEQ ID NO: 72.

2. The population of synthetic isolated peptides of claim 1 , wherein at least one of the three different peptides comprises the sequence selected from the group consisting of:

(a) SEQ ID NO: 72, wherein X 2 is A, X 5 is E, X 8 is T, X 10 is T, X 11 is G, X 12 is L, X 13 is Y, X 18 is D, X 20 is D, X 22 is S, X 23 is A, X 24 is A, X 25 is T, X 26 is 5, X 39 is K, X 44 is X 49 is E, X 56 is K, and X 58 is E;

(b) SEQ ID NO: 72, wherein X 2 is V, X 5 is D, X 8 is P, X 10 is V, X 11 is A, X 12 is V, X 13 is F, X 18 is N, X 20 is N, X 22 is V, X 23 is S, X 24 is I, X 25 is P, X 26 is N, X 39 is R, X 44 is R, X 49 is D, X 56 is Q, and X 58 is T;

(c) SEQ ID NO: 72, wherein X 2 is V, X 5 is D, X 8 is P, X 10 is V, X 11 is A, X 12 is V, X 13 is F, X 18 is N, X 20 is N, X 22 is V, X 23 is T, X 24 is I, X 25 is P, X 26 is K, X 39 is A, X 44 is Q, X 49 is Q, X 56 is R, and X 58 is D;

(d) SEQ ID NO: 72, wherein X 2 is A, X 5 is E, X 8 is T, X 10 is T, X 11 is A, X 12 is V, X 13 is F, X 18 is N, X 20 is N, X 22 is V, X 23 is T, X 24 is I, X 25 is P, X 26 is K, X 39 is H, X 44 is H, X 49 is N, X 56 is E, and X 58 is S;

(e) SEQ ID NO: 72, wherein X 2 is V, X 5 is D, X 8 is P, X 10 is V, X 11 is A, X 12 is V, X 13 is F, X 18 is N, X 20 is N, X 22 is S, X 23 is A, X 24 is A, X 25 is T, X 26 is S, X 39 is R, X 44 is R, X 49 is D, X 56 is Q, and X 58 is T;

(f) SEQ ID NO: 72, wherein X 2 is A, X 5 is E, X 8 is T, X 10 is V, X 11 is A, X 12 is V, X 13 is Y, X 18 is D, X 20 is D, X 22 is V, X 23 is S, X 24 is I, X 25 is T, X 26 is S, X 39 is K, X 44 is R, X 49 is D, X 56 is R, and X 58 is D;

(g) SEQ ID NO: 72, wherein X 2 is V, X 5 is D, X 8 is P, X 10 is V, X 11 is A, X 12 is V, X 13 is F, X 18 is N, X 20 is N, X 22 is S, X 23 is A, X 24 is A, X 25 is P, X 26 is N, X 39 is R, X 44 is K, X 49 is E, X 56 is K, and X 58 is E;

(h) SEQ ID NO: 72, wherein X 2 is A, X 5 is E, X 8 is T, X 10 is V, X 11 is A, X 12 is V, X 13 is Y, X 18 is D, X 20 is D, X 22 is V, X 23 is 5, X 24 is I, X 25 is T, X 26 is S, X 39 is A, X 44 is Q, X 49 is Q, X 56 is R, and X 58 is D;

(i) SEQ ID NO: 72, wherein X 2 is V, X 5 is D, X 8 is P, X 10 is V, X 11 is A, X 12 is V, X 13 is F, X 18 is N, X 20 is N, X 22 is S, X 23 is A, X 24 is A, X 25 is P, X 26 is N, X 39 is H, X 44 is H, X 49 is N, X 56 is E, and X 58 is S; and

(j) SEQ ID NO: 72, wherein X 2 is A, X 5 is E, X 8 is T, X 10 is T, X 11 is A, X 12 is V, X 13 is F, X 18 is N, X 20 is N, X 22 is V, X 23 is T, X 24 is I, X 25 is P, X 26 is K, X 39 is E, X 44 is D, X 49 is A, X 56 is W, and X 58 is S.

3. The population of synthetic isolated peptides of claim 1 , wherein said fragment comprises at least 40 contiguous amino acids from SEQ ID NO: 72.

4. The population of synthetic isolated peptides of claim 1 , wherein said fragment comprises amino acids 33 to 71 of SEQ ID NO: 72.

5. The population of synthetic isolated peptides of claim 1 , wherein each isolated peptide comprises an additional N-terminal peptide sequence that is a native OMP-1 sequence or non-OMP-1 Ehrlichia antigen.

6. The population of synthetic isolated peptides of claim 1 , wherein each isolated peptide comprises an additional C-terminal peptide sequence that is a native OMP-1 sequence or non-OMP-1 Ehrlichia antigen.

7. The population of synthetic isolated peptides of claim 1 , wherein each isolated peptide comprises at least 70, 75, 80, or 85 amino acids.

8. The population of synthetic isolated peptides of claim 1 , wherein one or more of the isolated peptides is conjugated to a ligand or is biotinylated.

9. The population of synthetic isolated peptides of claim 1 , wherein one or more of the isolated peptides is conjugated to avidin, streptavidin, neutravidin, serum albumin, keyhole limpet hemocyanin (KLH), an enzyme, or a metallic nanoparticle or nanoshell.

10. The population of synthetic isolated peptides of claim 1 , wherein the population of peptides is immobilized to a solid support optionally through a metallic nanolayer.

11. The population of synthetic isolated peptides of claim 10 , wherein the solid support is a plurality of beads, a flow path in a lateral flow immunoassay device, a well in a microtiter plate, or a flow path in a rotor.

12. The population of synthetic isolated peptides of claim 1 , wherein the population further comprises one or more antigenic peptides from an Ehrlichia species.

13. The population of synthetic isolated peptides of claim 12 , wherein said one or more antigenic peptides has a sequence of F-S-A-K-E-E-X 7 -A-E-T-R-X 12 -T-F-G-L-X 17 -K-Q-Y-D-G-A-X 24 -I-X 26 -E-N-Q-V-Q-N-K-F-T-I-S-N-C(SEQ ID NO: 71) or a fragment thereof, wherein X 7 is any amino acid, X 12 is any amino acid, X 17 is any amino acid, X 24 is any amino acid, and X 26 is any amino acid.

14. The population of synthetic isolated peptides of claim 13 , wherein:

X 7 in SEQ ID NO: 71 is K;

X 12 in SEQ ID NO: 71 is K or R;

X 17 in SEQ ID NO: 71 is E or D;

X 24 in SEQ ID NO: 71 is K or Q; and/or

X 26 in SEQ ID NO: 71 is E or T.

15. A method for detecting in a sample an antibody to an epitope of an Ehrlichia antigen, the method comprising:

contacting a sample with the population of synthetic isolated peptides of claim 1 ; and

detecting formation of an antibody-peptide complex comprising said one or more peptides in the population,

wherein formation of said complex is indicative of an antibody to an epitope of an Ehrlichia antigen being present in said sample.

16. The method of claim 15 , wherein said Ehrlichia antigen is from an Ehrlichia chaffeensis, Ehrlichia ewingii, Ehrlichia canis , or Ehrlichia muris species.

17. The method of claim 15 , wherein the population of synthetic isolated peptides is immobilized to a solid support optionally through a metallic nanolayer.

18. The method of claim 17 , wherein said solid support is a plurality of beads, a flow path in a lateral flow assay device, a well in a microtiter plate, or a flow path in a rotor.

19. The method of claim 15 , wherein said detecting step comprises (i) performing an ELISA assay, (ii) running a lateral flow assay, (iii) performing an agglutination assay, (iv) performing a Western blot, a slot blot, or dot blot, (v) performing a wavelength shift assay, or (vi) running the sample through an analytical or centrifugal rotor.

20. The method of claim 15 , wherein said sample is from a human, canine, or feline subject.

21. The method of claim 15 , wherein said sample is a blood, serum, plasma, cerebral spinal fluid, tissue extract, urine, or saliva sample.

22. The method of claim 15 , wherein the formation of a plurality of antibody-peptide complexes are detected, and wherein formation of said complexes is indicative of antibodies to epitopes of Ehrlichia antigens from multiple Ehrlichia species being present in said sample.

23. A method for diagnosing monocytic and/or granulocytic ehrlichiosis in a subject, the method comprising:

contacting a sample from the subject with the population of synthetic isolated peptides of claim 1 ; and

detecting formation of an antibody-peptide complex comprising said one or more peptides in the population,

wherein formation of the complex is indicative the subject having monocytic and/or granulocytic ehrlichiosis.

24. A kit comprising the population of synthetic isolated peptides of claim 1 and a labeling reagent capable of binding to an antibody that recognizes an epitope of said one or more peptides in the population.

25. The kit of claim 24 , wherein the population of synthetic isolated peptides is attached to or immobilized on a solid support optionally through a metallic nanolayer.

26. The kit of claim 24 , wherein the solid support is a plurality of beads, a tube or a well, a lateral flow assay device, or an analytical or centrifugal rotor.

27. The kit of claim 24 , wherein the labeling reagent is an anti-human, anti-canine, or anti-feline IgG or IgM antibody conjugated to a detectable label.

28. The kit of claim 27 , wherein the detectable label is an enzyme, a metallic nanoparticle, metallic nanoshell, metallic nanolayer, fluorophore, or colored latex particle.

29. The kit of claim 24 , wherein the labeling reagent is protein A, protein G, and/or a protein A/G fusion protein conjugated to a detectable label.

30. The kit of claim 29 , wherein the detectable label is an enzyme, a metallic nanoparticle, metallic nanoshell, metallic nanolayer, fluorophore, or colored latex particle.