Diagnostic performance of PCR and ELISA on blood and milk samples and serological survey for small ruminant lentiviruses in central Spain

Abstract

The diagnostic performance of an ELISA for the detection of antibodies to the small ruminant lentiviruses (SRLVs) maedi-visna virus and caprine arthritis-encephalitis virus in milk and corresponding blood samples was evaluated in 50 sheep. The agreement between ELISA results in blood and milk was 90 per cent, and the κ value was 0.79. In addition, a serological survey in the central zone of Spain was performed using milk samples from 413 animals (250 sheep and 163 goats) from 12 flocks/herds. All flocks/herds had some animals that were positive for SRLV. Among the animals, 60.0 per cent of the sheep and 8.0 per cent of the goats tested were seropositive. Each sample was also tested using a PCR technique, which increased the percentage of positive animals detected. Using a combination of ELISA and PCR gave a total of 72.2 per cent of sheep and 28.8 per cent of goats positive for SRLV.

Maedi in slaughtered sheep: A pathology and polymerase chain reaction study in southwestern Iran

“…Their results indicated that the LTR determined the extended cell tropism of the MVV. Therefore, in live animals, virus isolation can be conducted on peripheral blood, milk and inhalation of infected alveolar macrophages (Christodoulopoulos 2006;Gil et al 2006;McNeilly et al 2008;Barquero et al 2011). At necropsy, MVV can be isolated from the lungs, mediastinal lymph nodes, spleen, third eyelids and kidneys of affected animals (Capucchio et al 2003;Angelopoulou et al 2006;Benavides et al 2006;Laamanen et al 2007).…”

Transmissibilidade de Lentivírus de Pequenos Ruminantes para cabritos e cabras adultas por meio de sêmen infectado experimentalmente

“…Gregory et al (2011), utilizando as técnicas de PCR e Nested-PCR para detecção do cDNA em amostras de leite, observaram 19,4% (14/72) amostras positivas na primeira reação e 22,2% (16/72) na segunda. A técnica para nested--PCR possui outras desvantagens relatadas, como baixa porcentagem de positivos (Gonzales et al 2013), baixa sensibilidade (Andrés et al 2005) e falsos positivos , Brinkhof et al 2010, Barquero et al 2011. Os resultados negativos para o nested-PCR não devem ser interpretados como falsos negativos, pois é observada intermitência da presença do DNA pró-viral em sêmen e sangue (Andrioli et al 2006, Minardi 2009).…”

“…No entanto, estes animais não devem ser considerados falsos positivos, pois é relatada a eventual soroconversão tardia (Barquero et al 2011). Outra hipótese está relacionada à possível falha do kit comercial em detectar anticorpos relativos ao maior número de epítopos de superfície de Lentivírus e, por este motivo, resultar em muitos falsos negativos.…”

Investigation of risk factors associated with infections caused by small ruminant lentiviruses

“…Milk samples were used for the diagnosis of SRLV. A procedure, which is supported by the results of different studies, was applied (2,5,16). The commercial ELISA (Elitest Hyphen-Biomed, France) was used for the diagnosis (23).…”

“…The OIE recommended the use of either agar gel immunodiffussion (AGID) or enzyme-linked immunosorbent assay (ELISA). Milk as substrate for the ELISA has been demonstrated as an alternative to blood in several studies (2,5,16), and its use simplifies the collection of samples.…”