The study indicates that bats are a reservoir for an unknown arenavirus


In a recent study published in the Journal of the US Centers for Disease Control and Prevention (CDC), Emerging infectious diseasesa team of researchers reported the discovery of arenavirus RNA (RNA) from various bat species that were sampled between 2007 and 2011 from Brazil.

Study: highly diverse arenaviruses in tropical bats, Brazil.  Image credit: Kateryna Kon/Shutterstock
Stady: Arenaviruses are highly diversified in tropical bats, Brazil. Image credit: Kateryna Kon/Shutterstock

background

Of the four genera in the family Arenaviridae, Mammarenavirus It is the only genus that infects mammals. The genus is divided into New World arenaviruses and the worldwide circulating Lassa choriovirus serogroup. Some New World arenaviruses, such as the Junin, Chapare, Guanarito, Machupo, and Sabia viruses, cause hemorrhagic fevers in humans.

While pathogenic arenaviruses are generally transmitted to humans through infected rodents, Tacaribe mammarenavirus, It is found in bats and is not considered contagious to humans, and is known anecdotally to cause flu-like symptoms. Although bats are known to host zoonotic viruses, there is limited epidemiological evidence of association between bats and naked viruses, which mostly consist of a single virus isolated and experimental infection of bats.

However, since Tacaribe virus belongs to the same family as viruses causing hemorrhagic fever that also exhibit immune evasion and cellular swelling, the possibility of severe infection from Tacaribe virus cannot be ruled out.

about studying

In the current study, the researchers collected samples from bats from southeastern Brazil and analyzed spleen, lung, intestine, kidney, and liver tissue from the samples. They collected a total of 1,047 bats from 32 species and analyzed 3,670 tissue samples. To detect arenavirus RNA, they performed reverse transcription polymerase chain reaction (RT-PCR) with modified primers to amplify partial sequences of the New World RNA-dependent RNA polymerase gene.

Furthermore, they used Illumina-based deep sequencing to obtain complete coding sequences of arenaviruses from two collected bat species. Sequences obtained from RT-PCR and complete coding sequences were used for phylogenetic analyzes and to determine homologous sequence distances.

consequences

The results reported arenavirus RNA from 1.62% (17 of 1047) of sampled bats belonging to three species—one Artibeus planirostrisfour Artibius Litoratus and 12 Carolia bracillata. Viruses from Monday Artibius Species identified as Tacaribe mammarenavirusWhile the virus was detected on 12 Carolia bracillata The samples were identified as a new species, which they named by the authors Titivirus Mmarena.

All samples were collected from forest and urban areas within 60 km of each other, indicating the presence of a potential viral reservoir in bats in the area. Similar viral concentrations were found in tissues of the spleen and lungs, indicating the presence of systemic infection. The highest concentration of arenavirus was found in the intestinal tissue sample, indicating enterocolitis virus secretion.

Phylogenetic reconstruction based on partial gene sequencing of RNA-dependent RNA polymerase recovered two New World arenaviruses from Brazil. Arenaviruses from Monday Artibius Species formed a single clade, while sequences from Carolia bracillata Samples formed another clade. The complete coding sequences revealed identical genome organization as other mammarenaviruses and formed a monophyletic group with Tacaribe virus that was well supported.

A maximum-likelihood tree using the complete large fragment genes recovered the complete set containing Tacaribe virus and sequences from Brazil as sister to the Junin and Machupo New World arenaviruses.

However, phylogenetic analysis using whole small segment genes showed a sister relationship between the Ocozocoautla de Espinosa virus and the clade with the Brazilian and Tacaribe virus sequences.

The Ocozocoautla de Espinosa virus is believed to have caused an outbreak of hemorrhagic fever in Mexico. Moreover, analyzes of recombination and sequence distances did not indicate any recombination events.

Taxonomic evaluation of new virus species Carolia bracillata Samples were based on pairwise sequence comparisons with Tacaribe virus which indicated a nucleotide sequence identity of less than 80%, an amino acid identity to a nucleocapsid protein of 88.6% to 90%, and the presence of a distinct host. The species is named after a river located near the sampling site.

conclusions

To summarize, the study examined bat species collected from southwestern Brazil for the presence of arenavirus RNA using sequence amplification methods. The results reported that arenavirus RNA from three bat species constituted 1.62% of the total sample volume.

Phylogenetic analyzes revealed that arenaviruses detected from bat samples are closely related to takarib virus, a New World arenavirus found in bats. One of the discovered arenaviruses is a new species and has been named Titivirus Mmarena.

While New World viruses are generally found in rodents, the results of this study indicate that bats could be reservoirs for arenaviruses and need further exploration.



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