Table 1.
Testing Methodology
| Pathogen | Laboratory methodology | Criteria for positivity | Refs. |
|---|---|---|---|
| Brucella spp. (Brucella abortus, Brucella melitensis, Brucella suis) | Total antibody titers were detected with a microagglutination test using the B. abortus strain 1119-3 as antigen with minor modifications from the reference method (discontinuation of safranin and use of U-bottom plates). This strain reacts with antibodies to naturally occurring strains of B. abortus, B. melitensis, and B. suis. It can also detect the Brucella marine strains. | A total antibody titer of ≥ 160 is a positive result. | Brown et al. (1981) |
| California serogroup bunyaviruses (JC, SSH) | Antibodies were detected using a plaque reduction neutralization test. Serum samples inhibiting at least 90% of possible plaque formation relative to virus controls were deemed positive for viral antibodies. | A titer of ≥ 1:20 is a positive result. | Beaty et al. (1995); Lowell et al. (2011); Rocheleau et al. (2017) |
| Coxiella burnetii | The commercial IgG ELISA (Virion Serion, Wurzburg, Germany) was used according to the manufacturer’s instructions with the exception that samples were diluted 1:100. Positive and borderline samples were further analyzed for both Phase I and Phase II IgG by IFA. The IFA has a sensitivity of 81% and a specificity of 90%. | A positive or equivocal ELISA and a Phase I and/or Phase II IFA titer ≥ 1:64 is a positive result. | Anderson et al. (2009); Kersh et al. (2013) |
| Cryptosporidium spp. (Cryptosporidium parvum, Cryptosporidium felis, Cryptosporidium hominis) | IgG antibodies were detected with a multiplex bead assay using Cp17 and Cp23 as antigen. The Cp17 assay has a sensitivity of 91% and a specificity of 87% compared with the gold standard western blot. The Cp23 assay is 95% sensitive and 100% specific. | Antibody response to ≥ 2 antigens is a positive result. | Priest et al. (2010) |
| Echinococcus granulosus | IgG antibodies were detected with Luminex bead technology using hydatid cyst fluid. This test has a sensitivity of 82% and a specificity of 99%. | A titer of >373.35 MFI is a positive result. | Zhang et al. (2012) |
| Echinococcus multilocularis | IgG antibodies were detected using an ELISA with Em18 antigen. This test has a sensitivity of 86% and a specificity of 99%. | A titer of >8.5U/μL is a positive result. | Ito et al. (2002) |
| Francisella tularensis (F. tularensis tularensis, F. tularensis holarctica) | Total antibodies were detected using a microagglutination test where the titer is determined by counting the last well of full agglutination. | A titer of ≥ 1:128 is a positive result. | Sato et al. (1990) |
| Giardia intestinalis | IgG antibodies were detected with a multiplex bead assay using VSP3 and VSP5 as antigen. This assay has a sensitivity of 93% for stool positive giardiasis patients.a | Antibody response to ≥ 2 antigens is a positive result. | Priest et al. (2010) |
| Hepatitis E Virus | IgG antibodies were detected using the DS-EIA-ANTI-HEV-G Kit (DSI, Italy). This assay uses the ORF2 region of the HEV genome as antigen. | OD ≥ (negative control +0.2) is a positive result. | Kodani et al. (2017) |
| Toxoplasma gondii | The commercial IgG enzyme immunoassay Platelia Toxo-G (Bio-Rad, Hercules, CA) was used according to the manufacturer’s instructions. This test has a sensitivity of 97% and a specificity of 100%. | A titer of >10 IU is a positive result. | Jones et al. (2007); Villard et al. (2016) |
| Trichinella spp. | IgG antibodies were detected using two ELISA kits, the Trichinella antibody detection test kit (Tn-96; Scimedx Corporation) with a sensitivity of 84% and a sensitivity of 94% and the Trichinella spiralis ELISA IgG Test kit (GSD01-3002; Gold Standard Diagnostics) with a sensitivity of >95% and a specificity of 95%.b | A titer of >43.15 is a positive result for the Scimedx kit. A titer of >11U is a positive result for the Gold Standard Diagnostics Kit. |
Gold Standard Diagnostics (2014); Ivanoska et al. (1989) |
a
n=14 for this comparison.
b
Due to logistical issues, 719 samples were tested using the Scimedx Kit, and 168 samples were tested using the Gold Standard Diagnostics Kit.
ELISA, enzyme-linked immunosorbent assay; IFA, immunofluorescence assay; JC, Jamestown Canyon; MFI, median fluorescence intensity; SSH, snowshoe hare.