Table 1. Serum samples screened for California serogroup virus IgM and IgM-positive samples, by patient group and date of collection, Finland, 2001–2013* .
| Patient group and date of sample collection† | Serum samples, no. | IgM-positive samples, no. | IgM prevalence, % |
|---|---|---|---|
| Suspected Puumala virus infection | |||
| 2001 May 25−Sep 4 | 1,294 | 2 | 0.15 |
| 2004 Jun 14–Sep 1 | 958 | 1 | 0.10 |
| 2012 Jun 5–Aug 21 | 498 | 2 | 0.40 |
| 2013 May 16–Sep 26 | 824 | 0 | 0 |
| Total |
3,574 |
5 |
0.14 |
| Neurologic symptoms | |||
| 2003 Jun 2–Sep 29 | 711 | 2 | 0.28 |
| 2004 Jun 10–Sep 17 | 868 | 2 | 0.23 |
| 2005 Jun 23–Oct 1 | 969 | 2 | 0.21 |
| 2007 Jun 20–Aug 30 | 563 | 0 | 0 |
| 2012 Jun 8–Oct 15 | 1,103 | 3 | 0.27 |
| Total |
4,214 |
9 |
0.21 |
| Suspected Inkoo virus infection | |||
| 2004 | 32 | 1 | 3.13 |
| 2005 | 30 | 0 | 0 |
| 2006 | 21 | 0 | 0 |
| 2007 | 31 | 0 | 0 |
| 2008 | 11 | 0 | 0 |
| 2009 | 15 | 0 | 0 |
| 2010 | 16 | 0 | 0 |
| 2011 | 14 | 0 | 0 |
| 2012 | 3 | 0 | 0 |
| Total |
173 |
1 |
0.58 |
| All patient groups |
7,961 |
15 |
0.19 |
| *Samples from patients were initially screened for Puumala virus, for agents causing neurologic infections, or Inkoo virus. Indirect immunofluorescence was used to screen for California serogroup virus IgM. †Sample collection for suspected Inkoo virus infection was for the entire year. | |||