Serotyping versus genotyping in infected sheep and goats with small ruminant lentiviruses

Small ruminant lentiviruses (SRLVs) belong to the genusLentivirusin the Retroviridae family. There are five genotypes (A, B, C, D, and E), where genotypes A and B have a global distribution and genotypes C, D, and E are limited to Europe. The presence of SRLV has been confirmed in Mexico, with genotype B detected in the central region of the country. We examined the presence of SRLVs and genotype prevalence in 1014 sheep and 1383 goats from 12 Mexican states. Using a commercial competitive ELISA (cELISA) test, we detected SRLV antibodies in 107 sheep (10.55%) and 466 goats (33.69%). We used an endpoint PCR to amplify the LTR region on seropositive animals. A total of 50 sheep and 75 goats tested positive via PCR. Positive amplicons from 11 sheep and 17 goats from ten Mexican States were cloned and sequenced. With the LTR sequence data obtained in this study, a phylogenetic analysis was performed; we also constructed a phylogenetic tree using the obtained sequences and GenBank’s available sequences. All studied sequences were associated with genotype B, specifically with the FESC-752 isolate previously identified in Mexico. Highly conserved transcription factor binding sites were observed in analyzed alignments, such as AML (vis), AP-4, and TATA box. However, we identified nucleotide differences at site AP-1 that suggest function loss. Our study found that ovine and caprine genotype B SRLVs are widely distributed in Mexico; a highly conserved LTR region among the sequences evaluated in this study was also found.

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Molecular Characterization of Small Ruminant Lentiviruses in Polish Mixed Flocks Supports Evidence of Cross Species Transmission, Dual Infection, a Recombination Event, and Reveals the Existence of New Subtypes within Group A

Viruses ◽

10.3390/v13122529 ◽

2021 ◽

Vol 13 (12) ◽

pp. 2529

Author(s):

Monika Olech ◽

Jacek Kuźmak

Keyword(s):

Small Ruminant ◽

Dual Infection ◽

Surface Glycoprotein ◽

Tata Box ◽

Sheep And Goats ◽

R Region ◽

Complex Picture ◽

Group A ◽

Small Ruminant Lentiviruses

Small ruminant lentiviruses (SRLVs) are a group of highly divergent viruses responsible for global infection in sheep and goats. In a previous study we showed that SRLV strains found in mixed flocks in Poland belonged to subtype A13 and A18, but this study was restricted only to the few flocks from Małopolska region. The present work aimed at extending earlier findings with the analysis of SRLVs in mixed flocks including larger numbers of animals and flocks from different part of Poland. On the basis of gag and env sequences, Polish SRLVs were assigned to the subtypes B2, A5, A12, and A17. Furthermore, the existence of a new subtypes, tentatively designed as A23 and A24, were described for the first time. Subtypes A5 and A17 were only found in goats, subtype A24 has been detected only in sheep while subtypes A12, A23, and B2 have been found in both sheep and goats. Co-infection with strains belonging to different subtypes was evidenced in three sheep and two goats originating from two flocks. Furthermore, three putative recombination events were identified within gag and env SRLVs sequences derived from three sheep. Amino acid (aa) sequences of immunodominant epitopes in CA protein were well conserved while Major Homology Region (MHR) had more alteration showing unique mutations in sequences of subtypes A5 and A17. In contrast, aa sequences of surface glycoprotein exhibited higher variability confirming type-specific variation in the SU5 epitope. The number of potential N-linked glycosylation sites (PNGS) ranged from 3 to 6 in respective sequences and were located in different positions. The analysis of LTR sequences revealed that sequences corresponding to the TATA box, AP-4, AML-vis, and polyadenylation signal (poly A) were quite conserved, while considerable alteration was observed in AP-1 sites. Interestingly, our results revealed that all sequences belonging to subtype A17 had unique substitution T to A in the fifth position of TATA box and did not have a 11 nt deletion in the R region which was noted in other sequences from Poland. These data revealed a complex picture of SRLVs population with ovine and caprine strains belonging to group A and B. We present strong and multiple evidence of dually infected sheep and goats in mixed flocks and present evidence that these viruses can recombine in vivo.

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Retroviral Infections in Sheep and Goats: Small Ruminant Lentiviruses and Host Interaction

Viruses ◽

10.3390/v5082043 ◽

2013 ◽

Vol 5 (8) ◽

pp. 2043-2061 ◽

Cited By ~ 24

Author(s):

Amaia Larruskain ◽

Begoña Jugo

Keyword(s):

Small Ruminant ◽

Sheep And Goats ◽

Host Interaction ◽

Small Ruminant Lentiviruses ◽

Retroviral Infections

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Molecular characterization and phylogenetic analysis of small ruminant lentiviruses isolated from Canadian sheep and goats

Virology Journal ◽

10.1186/1743-422x-8-271 ◽

2011 ◽

Vol 8 (1) ◽

Cited By ~ 18

Author(s):

Yvan L'Homme ◽

Mourad Ouardani ◽

Valérie Lévesque ◽

Giuseppe Bertoni ◽

Carole Simard ◽

...

Keyword(s):

Phylogenetic Analysis ◽

Molecular Characterization ◽

Small Ruminant ◽

Sheep And Goats ◽

Small Ruminant Lentiviruses

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Phylogenetic Analysis of Belgian Small Ruminant Lentiviruses Supports Cross Species Virus Transmission and Identifies New Subtype B5 Strains

Pathogens ◽

10.3390/pathogens9030183 ◽

2020 ◽

Vol 9 (3) ◽

pp. 183 ◽

Cited By ~ 3

Author(s):

Rodolphe Michiels ◽

Nadjah Radia Adjadj ◽

Nick De Regge

Keyword(s):

Small Ruminant ◽

Genetic Characterization ◽

Control Program ◽

Sequence Information ◽

Sheep And Goats ◽

Goat Population ◽

Depth Analysis ◽

Small Ruminant Lentiviruses

Small ruminant lentiviruses (SRLV) are a group of highly divergent viruses responsible for global and fatal infections in sheep and goats. Since the current phylogenetic classification of these viruses was proposed in 2004, it nowadays consists out of 5 genotypes and 28 subtypes. In support of our national SRLV control program, we performed the genetic characterization of SRLV strains circulating in the Belgian sheep and goat population. Fourteen sheep and 9 goat strains were sequenced in the gag-pol and pol regions using the method described by Shah. Most SRLV strains from sheep and goats belonged to prototype A1 and B1 subtypes, respectively. We, however, also found indications for cross-species transmission of SRLV strains between sheep and goats and vice versa, and identified a new subtype designated as B5. An in-depth analysis of the current SRLV phylogeny revealed that many subtypes have been defined over the years based on limited sequence information. To keep phylogeny as a useful tool, we advocate to apply more rigorous sequencing standards to ensure the correct classification of current and new emerging strains. The genetic characterization of Belgian SRLV strains will help in the development of appropriate diagnostic tools to assist the national control program.

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Worldwide Prevalence of Small Ruminant Lentiviruses in Sheep: A Systematic Review and Meta-Analysis

Animals ◽

10.3390/ani11030784 ◽

2021 ◽

Vol 11 (3) ◽

pp. 784

Author(s):

Ricardo de Miguel ◽

Marta Arrieta ◽

Ana Rodríguez-Largo ◽

Irache Echeverría ◽

Raúl Resendiz ◽

...

Keyword(s):

Systematic Review ◽

Small Ruminant ◽

Meta Analysis ◽

Geographical Area ◽

Small Ruminants ◽

Strong Positive Correlation ◽

Scientific Publications ◽

Serological Tests ◽

Gold Standard Method ◽

Small Ruminant Lentiviruses

Small Ruminant Lentiviruses (SRLV) are highly prevalent retroviruses with significant genetic diversity and antigenic heterogeneity that cause a progressive wasting disease of sheep called Maedi-visna. This work provides a systematic review and meta-analysis of the last 40 years (1981–2020) of scientific publications on SRLV individual and flock prevalence. Fifty-eight publications and 314 studies were included. Most articles used a single diagnostic test to estimate prevalence (77.6%), whereas articles using three or more tests were scarce (6.9%). Serological tests are more frequently used than direct methods and ELISA has progressively replaced AGID over the last decades. SRLV infection in sheep is widespread across the world, with Europe showing the highest individual prevalence (40.9%) and being the geographical area in which most studies have been performed. Africa, Asia, and North America show values between 16.7% to 21.8% at the individual level. South and Central America show the lowest individual SRLV prevalence (1.7%). There was a strong positive correlation between individual and flock prevalence (ρ = 0.728; p ≤ 0.001). Despite the global importance of small ruminants, the coverage of knowledge on SRLV prevalence is patchy and inconsistent. There is a lack of a gold standard method and a defined sampling strategy among countries and continents.

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