Serological Survey of Bluetongue Virus Serotype-8 Infection in South American Camelids in Switzerland (2007-2008)

Abstract

Background: Outbreak of bluetongue virus serotype-8 (BTV-8) infection in domestic ruminants in Northern Europe. Objective: To investigate the South American camelids' (SAC) susceptibility to BTV-8 infection, their role in the epidemiology of the disease, and the use of currently available serological screening tests in SAC in an endemic region.Animals: Three hundred and fifty-four unvaccinated and 27 vaccinated SAC (170 llamas, 201 alpacas), ranging in age from 1 month to 17 years between June and August 2008. The SAC originated from 44 herds throughout the country, representing 10% of the Swiss SAC population.Methods: Prospective, observational study of a convenience sample of SAC. Serum samples were analyzed with 2 serological screening tests. When results diverged, a 3rd ELISA was carried out for confirmation (ID Screen Bluetongue Competition ELISA kit).Results: All sera from the 354 unvaccinated animals were negative in the endemic region. Reliable seroconversion was observed after administration of 2 doses of vaccine.Conclusions and Clinical Importance: This study suggests a low susceptibility of SAC to BTV-8 despite the presence of the virus in the cattle and small ruminant population, indicating that SAC do not play a major role in the epidemiology of BTV-8. Furthermore, these results indicate that commercially available serological tests for BTV-8 can be used in SAC.

Sentinel surveillance of selected veterinary and public health pathogens in camel population originating from Southern Punjab province, Pakistan

“…Such an evidence argues for host-dependent potential of each of the BTV serotypes simply because, compared to other serotypes such as 4, 6, 8, 11, 14 and 16, a previous study observed an increased incidence of serotype 1 in camels (Drif et al, 2018). Though camels is generally conceived to be a non-susceptible host for BTV in the past, experimental investigations have suggested otherwise, where, particularly for serotype 1 and 8, a low rate of replication or infection along with development of neutralizing antibodies have been evidenced and therefore may serve as potential source of infection for susceptible hosts living in close proximity (Zanolari et al, 2010;Batten et al, 2011;Schulz et al, 2012). Thus, routine BT surveillance in camels should be conducted in disease endemic region/s in order to elucidate disease epidemiology and future interventions for its control.…”

Humoral Response to 2 Inactivated Bluetongue Virus Serotype-8 Vaccines in South American Camelids

“…Antibodies against BTV‐8 were determined with the Bluetongue Virus Antibody Test kit e , 14 . This cELISA was performed according to the manufacturers' recommendations.…”

Variation inBluetongue virusreal-time reverse transcription polymerase chain reaction assay results in blood samples of sheep, cattle, and alpaca

“…8,18 Conflicting findings were reported in Switzerland where a serological survey indicated that exposed animals were serologically negative by competitive enzymelinked immunosorbent assay, suggesting that New World camelids had not played an important role in BTV-8 spread since 2007. 27 There is however little information regarding the impact of different BTV serotypes, as well as different arthropod vectors, on the manifestation and susceptibility of New World camelids to BT exposure and infection.…”