Enteric Viral Infections among Domesticated South American Camelids: First Detection of Mammalian Orthoreovirus in Camelids

Abstract

Enteric infections are a major cause of neonatal death in South American camelids (SACs). The aim of this study was to determine the prevalence of enteric viral pathogens among alpacas and llamas in Canchis, Cuzco, located in the southern Peruvian highland. Fecal samples were obtained from 80 neonatal alpacas and llamas and tested for coronavirus (CoV), mammalian orthoreovirus (MRV), and rotavirus A (RVA) by RT-PCR. Of the 80 fecal samples analyzed, 76 (95%) were positive for at least one of the viruses tested. Overall, the frequencies of positive samples were 94.1% and 100% among alpacas and llamas, respectively. Of the positive samples, 33 (43.4%) were monoinfected, while 43 (56.6%) had coinfections with two (83.7%) or three (16.3%) viruses. CoV was the most commonly detected virus (87.5%) followed by MRV (50%). RVA was detected only in coinfections. To our knowledge, this is the first description of MRV circulation in SACs or camelids anywhere. These data show that multiple viruses circulate widely among young alpaca and llama crias within the studied areas. These infections can potentially reduce livestock productivity, which translates into serious economic losses for rural communities, directly impacting their livelihoods.

Keywords: Peru; alpacas; coronavirus; llamas; mammalian orthoreovirus; rotavirus.

Figure 1

Polyacrylamide gel electrophoresis (PAGE) analysis of MRV dsRNA. PAGE of three strains isolated from intestinal contents of two alpacas (SA44 and H8) and one llama (SL7) in MA-104 cell line showing the 10 characteristic genomic segments of MRV: (A) SA-11 RVA strain exhibiting the typical 4–2–3–2 pattern (11 segments of dsRNA); (B) SA44 strain isolated showing a coinfection of RVA (11 genomic segments) and MRV (10 genomic segments); (C and D) strains H8 and SL7 exhibiting MRV monoinfection, showing the 10 dsRNA segments characteristic of MRV. Each segment of dsRNA is classified by size: genes L1–L3 (large segments), M1–M3 (medium segments) and S1–S4 (short segments) encode the proteins λ3–λ1, μ2-μNS, and σ1–σ3, respectively.

Figure 2

Phylogenetic trees constructed from partial nucleotide sequences (1069 bp) of the sigma 1 gene from MRV strains. Distances were corrected with the GTR-G model. Phylogenetic trees were constructed using the maximum likelihood method. Statistical support was provided by bootstrapping 1000 pseudoreplicates. Bootstrap values > 75% are given at branch nodes. The distance scale reflects substitutions/site. Reference samples are identified by GenBank accession numbers. In black, reference strains for each serotype.