Table 2. Results of serologic testing for arboviruses and Lyme disease for 3 patients with tick-borne encephalitis, Loire and Haute-Loire, Auvergne-Rhône-Alpes Region, France, 2017–2018*.
| Case no., sample |
Days after clinical onset |
TBEV |
|
DENV |
|
CHIKV |
|
ZIKV |
|
WNV |
|
TOSV |
|
Borrelia burgdorferi
|
|||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| IgM |
IgG |
IgM |
IgG |
IgM |
IgG |
IgM |
IgG |
IgM |
IgG |
IgM |
IgG |
IgM |
IgG |
||||||||
| 1 | |||||||||||||||||||||
| CSF | 16 | 4.3 | 3.22 | 1 | 1.12 | <1 | <1 | <1 | 1 | 1 | 1.14 | ND | ND | ||||||||
| Serum | 19 | 6.6 | 2.94 | 1.16 | 1.24 | <1 | 1.1 | ND | ND | <1 | 1.24 | <1 | 1 | Neg | Neg | ||||||
| Serum |
48 |
7.1
|
10.6
|
|
1.11 |
1.10 |
|
1 |
1 |
|
ND |
ND |
|
ND |
ND |
|
ND |
ND |
|
|
|
| 2† | |||||||||||||||||||||
| CSF |
15 |
53.4
|
748.62
|
|
ND |
ND |
|
ND |
ND |
|
ND |
ND |
|
ND |
ND |
|
ND |
ND |
|
Neg |
Neg |
| 3 | |||||||||||||||||||||
| CSF | 2 | 2.84 | 1.74 | 1.09 | <1 | <1 | <1 | <1 | <1 | <1 | 1 | ND | ND | Pos‡ | |||||||
| Serum | ND | ND | ND | ND | ND | ND | ND | ND | ND | ND | ND | ND | ND | Neg | Pos | ||||||
| CSF | 10 | 7.26 | 6.41 | 1.05 | 1.41 | <1 | 1.02 | <1 | <1 | <1 | 1.39 | <1 | <1 | Pos | |||||||
| Serum‡ | 10 | 2.34 | 3.02 | <1 | <1 | <1 | <1 | <1 | <1 | <1 | <1 | <1 | <1 | Neg | Pos | ||||||
| Serum | 61 | 4.02 | 5.19 | 1.02 | 2.10 | 1.02 | <1 | <1 | 1 | 1.06 | 3.70 | ND | ND | ND | ND | ||||||
*For cases 1 and 3, the results of ELISA serologic testing performed at the National Reference Centre for Arboviruses (Marseille, France) are expressed as the ratio between the optical density obtained with each viral antigen and the optical density with the control antigen. A ratio of <2.5 is considered a negative result; a ratio of 2.5–3.0 is considered an undetermined result; a ratio of >3 is considered a positive result. Lyme borreliosis serology was performed with Vidas immunoassays (bioMérieux, https://www.biomerieux.com). Serum specimens reacting for Borrelia burgdorferi IgG were also tested with Western blot; reactivity was observed for all cases with the lipoprotein VIse (a variable surface antigen of B. burgdorferi), and 17-, 39-, and 83-KDa proteins. Serologic testing for case-patient 2 was performed at the Laboratory of Virology at Strasbourg (Strasbourg, France) by using commercial assays (SERION ELISA classic TBE Virus IgG/IgM; https://www.virion-serion.de/en) and were interpreted according to the manufacturer’s instructions; results are expressed as U/mL, and positive cutoff values were 15 U/mL for TBEV IgM and 150 U/mL for TBEV IgG. Lyme borreliosis serology was performed with Enzygnost immunoassays (Siemens, https://www.siemens-healthineers.com). Boldface indicates positive results. CHIKV, chikungunya virus; CSF, cerebrospinal fluid; DENV, dengue virus; ND, not done; TBEV, tick-borne encephalitis virus; TOSV, Toscana virus; WNV, West Nile virus; ZIKV, Zika virus. †Serologic testing could not be performed on serum sample. ‡The Reiber index showed a CSF/serum IgG ratio of 1.03 (i.e., an equivocal result of <2).