OBJECTIVE To identify rabies virus variants (RVVs) isolated from bats and terrestrial mammals in Nuevo Leon between 2008 and 2015 and Coahuila in 2006. SAMPLE RVVs isolated from 15 bats and terrestrial mammals in Nuevo Leon and from a cow (Bos taurus) in Coahuila, along with 46 reference rabies virus sequences. PROCEDURES Antigenic characterization of the 16 isolates was performed with an indirect fluorescent antibody technique. Genomic sequencing of the nucleoprotein gene in the 16 isolates was performed with a reverse transcription PCR assay. Phylogenetic reconstruction of the 62 sequences was performed by means of Bayesian inference. RESULTS 9 isolates from bats and 1 isolate from a domestic cat that became infected as a result of contact with a Mexican free-tailed bat all clustered in the lineage associated with Lasiurus spp in the Americas or the lineage associated with Tadarida brasiliensis mexicana. An isolate from a domestic dog was identified as a variant associated with the dog-coyote lineage. The RVV isolated from a fox clustered in an Arizona fox lineage. The 3 RVVs from skunks (Mephitis macroura) were placed in a lineage with variants isolated from spotted skunks (Spilogale putorius). The RVV isolated from the cow was clustered in a lineage associated with foxes in Texas and separate from the lineage for the fox from Nuevo Leon. CONCLUSIONS AND CLINICAL RELEVANCE Results reinforced the need for Mexico to implement rabies surveillance and monitoring programs for bats and wild-living terrestrial carnivores.
In 2019, the World Health Organization (WHO) and the Pan-American Health Organization (PAHO) recognized Mexico as a country free of human rabies transmitted by dogs. Nevertheless, the sylvatic cycle remains as a public health concern in the country. Although cougars (Puma concolor) are not reservoirs of any rabies virus variant (RVV), these felines could act as vectors at the top of the food chain, and their relationships with other organisms must be considered important for the regulatory effect on their prey’s populations. In this study, genetic and antigenic characterization was performed on all cougar rabies cases diagnosed at the Rabies Laboratory Network of the Ministry of Health (RLNMH) in Mexico from 2000 to 2021. Samples from other species, a skunk, a horse (Equus caballus) (attacked by a cougar), and a gray fox (Urocyon cineroargenteus), were included as reference. Rabies cases in cougars were restricted to two Northern states of Mexico (Sonora and Chihuahua). Five out of six samples of cougars were RVV7 (Arizona gray fox RVV) and one from Sonora was RVV1. Interestingly, there is no evidence of RVV1 in dogs in the Northern states since the 1990s but skunk species now harbor this RVV1 in this region of the country.
In humans, co‐infection of hepatitis B and C viruses (HBV, HCV) is common and aggravates disease outcome. Infection‐mediated disease aggravation is poorly understood, partly due to lack of suitable animal models. Carnivores are understudied for hepatitis virus homologues. We investigated Mexican carnivores (ringtails, Bassariscus astutus) for HBV and HCV homologues. Three out of eight animals were infected with a divergent HBV termed ringtail HBV (RtHBV) at high viral loads of 5 × 109 –1.4 × 1010 copies/ml serum. Two of the RtHBV‐infected animals were co‐infected with a divergent hepacivirus termed ringtail hepacivirus (RtHV) at 4 × 106–7.5 × 107 copies/ml in strain‐specific qRT‐PCR assays. Immunofluorescence assays relying on HBV core and RtHV NS3/4a proteins indicated that none of the animals had detectable hepadnavirus core‐specific antibodies, whereas one RtHV‐infected animal had concomitant RtHV‐specific antibodies at 1:800 end‐point titre. RtHBV and RtHV complete genomes showed typical HBV and HCV structure and length. All RtHBV genomes were identical, whereas RtHV genomes showed four amino acid substitutions located predominantly in the E1/E2‐encoding genomic regions. Both RtHBV (>28% genomic nucleotide sequence distance) and RtHV (>30% partial NS3/NS5B amino acid sequence distance) formed new species within their virus families. Evolutionary analyses showed that RtHBV grouped with HBV homologues from different laurasiatherian hosts (carnivores, bats, and ungulates), whereas RtHV grouped predominantly with rodent‐borne viruses. Ancestral state reconstructions showed that RtHV, but not RtHBV, likely emerged via a non‐recent host switch involving rodent‐borne hepacivirus ancestors. Conserved hepatitis virus infection patterns in naturally infected ringtails indicate that carnivores may be promising animal models to understand HBV/HCV co‐infection.
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