Saliva as an alternative specimen for detection of Schmallenberg virus-specific antibodies in bovines

Abstract

BackgroundSchmallenberg virus (SBV), discovered in continental Europe in late 2011, causes mild clinical signs in adult ruminants, including diarrhoea and reduced milk yield. However, fetal infection can lead to severe malformation in newborn offspring. Enzyme-linked immunosorbent assays (ELISA) are commercially available for detection of SBV-specific antibodies in bovine sera and milk. Here we describe the development and evaluation of an indirect ELISA based on a yeast derived recombinant SBV nucleocapsid protein (N) for the detection of SBV-specific antibodies in bovine saliva. Development of a non-invasive test to detect antibodies in individual bovine saliva samples could potentially provide a test suitable for calves and adult cattle. The aim of this study was to investigate the agreement between the levels of antibodies (IgG) measured in milk and sera, and the level of antibodies (IgG and IgA) in saliva, in comparison with the antibody levels detected in sera and milk with commercially available test.ResultsSerum, milk and saliva samples from 58 cows were collected from three dairy herds in Lithuania and tested for the presence of SBV-specific antibodies. The presence of IgG antibodies was tested in parallel serum and milk samples, while the presence of IgA and IgG antibodies was tested in saliva samples. The presence of SBV-specific IgG and IgA in saliva was tested using an indirect ELISA based on a yeast-derived recombinant N protein. The presence of SBV-specific IgG in milk and sera was tested in parallel using a commercial recombinant protein based test. The sensitivities of the newly developed tests were as follows: 96 % for the IgG serum assay and 94 % for the IgG milk assay and 85 % and 98 % for IgG and IgA in saliva tests, when compared with data generated by a commercial IgG assay.ConclusionsData from testing the saliva IgG and IgA and also the milk and serum IgG with indirect SBV-specific ELISAs showed close agreement with the commercial serum and milk IgG assay data. The level of IgG in saliva was notably lower in comparison to IgA. The newly developed method exhibits the potential to serve as an easily transferable tool for epidemiological studies.Electronic supplementary materialThe online version of this article (doi:10.1186/s12917-015-0552-0) contains supplementary material, which is available to authorized users.

Evaluation of P22 ELISA for the Detection of Mycobacterium bovis-Specific Antibody in the Oral Fluid of Goats

“…In this context, the IgG concentration in the oral fluid from goats is significantly lower than that in swine ( 35 ), which may explain the differences in the Se previously stated. The IgA-antibody levels in ruminants are, on the contrary, higher than in other species, which could explain the differences observed in the diagnosis when employing IgA or IgG based-ELISAs for other infections such as Schmallenberg disease ( 23 ). Moreover, recent studies support the theory that the detection of IgA in oral fluid samples appears to be more robust and stable over time in pigs ( 20 ).…”

“…Finally, it is necessary to state that, in this study, a goat model was used to evaluate the performance of the P22 ELISA when using oral fluid samples. Previous studies have shown promising results of antibody-based platforms for the diagnosis of other diseases (e.g., FMDV or SVB) when using oral fluid samples in cattle ( 22 , 23 ). The results from the present study suggest a similar or limited performance of the P22 ELISA in oral fluid samples from cattle owing to the high diagnostic pressure as a consequence of the official eradication programmes, since it is difficult to find animals in an advance stage of infection.…”

“…Despite their use in swine populations, few studies have evaluated serological tests by employing oral fluid samples in ruminants in order to detect antibodies against foot and mouth disease virus (FMDV) or Schmallenberg virus (SBV) in bovines ( 22 , 23 ). With regard to TB, no studies using oral fluid samples for the antibody-based diagnosis of TB in domestic ruminants have, to the best of the authors' knowledge, been published previously.…”

Contemporary diagnostic approaches for pseudorabies (Aujeszky's disease) virus based on swine oral fluid specimens

“…Among 3,324,689 HIV tests conducted in the U.S. in 2011, 7% of the conventional laboratory tests (nucleic acid testing and immunoassays) and 23% of rapid antibody tests were performed on oral fluid specimens (APHL, 2013). For veterinary medicine, the detection of pathogen-specific antibodies in oral fluids has been demonstrated for rabies virus in dogs, feline immunodeficiency virus and feline leukemia virus in domestic cats, foot-and-mouth disease virus (FMDV) and Schmallenberg virus in cattle, and African swine fever virus (ASFV), FMDV, classical swine fever virus, influenza A virus (IAV), porcine epidemic diarrhea virus (PEDV), porcine reproductive and respiratory syndrome virus (PRRSV), transmissible gastroenteritis virus (TGEV), porcine respiratory coronavirus (PRCV), Seneca Valley virus A (SVA), and swine vesicular disease virus in swine (Archetti et al, 1995;Lazutka et al, 2015;Prickett and Zimmerman, 2010;Rotolo et al, 2018;Senthilkumaran et al, 2017).…”