Schmallenberg virus infection in South American camelids: Field and experimental investigations

- Virological results of experimentally SBV-infected SAC were similar to ruminants.
- SBV seroprevalence in South American camelids in Germany was similar to ruminants.
- SBV causes subclinical infection in SAC.
- In contrast to ruminants, abortion and congenital malformation are unlikely in SAC.
- Serological and virological methods were validated for SBV-diagnosis in SAC.

During the first epizootic wave of the novel, teratogenic Schmallenberg virus (SBV, Orthobunyavirus) in ruminants in Northern Europe, serological evidence of a previous SBV-infection demonstrated that South American camelids (SAC) are also susceptible to SBV. However, their potential role in SBV spread remains unknown. To investigate the prevalence and course of SBV-infection in SAC, a German field study and an animal trial with three llamas and three alpacas were conducted.From September 2012 to December 2013, 313 of 502 SAC (62.35%) were found SBV seropositive, but negative for SBV-RNA. The estimated between-district (94.23% of 52) and median within-district (71.43%) and herd (73.13%) SBV seroprevalence in German SAC was similar to the seroprevalence reported in cattle herds and sheep flocks at the time. An age of >1 year was found a statistically significant risk factor for SBV-infection, which could be explained by the spatio-temporal spread of SBV in Germany during the study period. No clinical signs or an increase of abortion and congenital malformation associated with SBV-infection in SAC were reported by the study participants.Similar to SBV-infected ruminants, SBV-RNAemia in experimentally SBV-infected SAC was detected for a short time between days 3 and 7 after infection (dpi), and seroconversion occurred between 9 and 21 dpi.Despite the similar virological and serological results, the lack of clinical signs and congenital malformation associated with SBV-infection suggests that SBV causes subclinical infection in SAC. However, their role as reservoirs in the spread of SBV has to be further investigated.