A new bat-borne hantavirus detected in Africa

a recent virus journal study analyzes the Kiwira virus, which belongs to the Hantaviridae family, including its discovery, phylogenetic location, and tissue distribution of viral ribonucleic acid (RNA).

To study: Kiwira virus, a newly discovered hantavirus discovered in free-tailed bats (Molossidae) in eastern and central Africa. Image Credit: Kateryna Kon / Shutterstock.com

What are hantaviruses?

Hantavirus belonging to the Hantaviridae family has trisegmented RNA genomes. The small genomic segment (S) encodes the nucleocapsid protein (N), while the medium segment (M) encodes the envelope glycoproteins, and the large genomic segment (L) encodes RNA-dependent RNA polymerase.

Several small mammals can harbor hantaviruses, most notably rodents, followed by shrews, bats, and moles. Several hantaviruses are capable of infecting humans, all of which have originated in rodents and belong to the orthohantavirus gender. Upon infection in humans, hantaviruses cause fever, followed by renal and respiratory failure, which may ultimately lead to organ failure.

Bat-borne hantaviruses, belonging to the Mobatvirus either loanvirus genders, have been reported in 14 species of bats throughout Asia, Europe and Africa. Nevertheless, these viruses have yet to be isolated and cultured; therefore, its potential to infect humans is not fully understood.

About the study

In the current study, bats were captured in the Democratic Republic of Congo (DRC) and southwestern Tanzania in 2017 and subsequently anesthetized and euthanized. All the intestines, kidneys, lungs, spleen and liver of the bats were collected.

Tissue samples were collected for viral RNA extraction and analysis by reverse transcriptase-polymerase chain reaction (RT-PCR) assay. In addition, phylogenetic analyzes were also performed.

Study findings

PCR analysis revealed the presence of hantavirus sequences in six of 334 bats from Tanzania and one of 49 bats obtained from the Democratic Republic of the Congo.

In particular, virus isolates from bats from Tanzania and the Democratic Republic of the Congo shared 98.6% identity. The highest pairwise identities were observed between Quezon and Robinia viruses of up to 82.9% and 81.4%, respectively.

All of the Hantavirus-positive bats obtained from Tanzania were Angolan free-tailed bats, also known as condylurus mopsthat belong to the Molossidae family. This species was not previously known to harbor hantavirus.

Of the six hantavirus-positive bats from Tanzania, one was female and five were male. The only positive bat from the Democratic Republic of the Congo was male; however, the species of this bat could not be determined.

The hantavirus-negative bats belonged to Molossidae (89), pteropodidae (226), Hipposideridae(1), Rhinolophidae (3), and Vespertilionidae (39) families, while the remaining 18 bat species could not be identified.

All tissues collected from the Tanzanian hantavirus-positive bats tested positive for viral RNA, except for one bat in which the lungs were the only organ positive for this virus. In particular, two bats exhibited the highest viral loads in their spleens.

A new virus sequence was observed in Tanzanian bats and was later named “Kiwira” virus within the Mobatavirus gender. This discovery makes Kiwira virus the fourth bat-borne hantavirus identified in Africa.

The complete nucleocapsid and glycoprotein precursor amino acid sequences of the new Kiwira virus could not be obtained for further analysis. The closest relatives of the Kiwira virus include the Robina and Quezon viruses.

Bats infected with Kiwira virus exhibited systemic infection, including involvement of the kidneys and intestines. Therefore, it is likely that hantavirus can be excreted in both urine and feces.

conclusions

M. condylurus Bats circulate throughout Africa, often found in hollow buildings and trees and in various parts of tropical and savannah regions ranging from western to eastern African countries. In addition to the widespread distribution of these bats across Africa, the proximity of the bats captured in this study to human settlements raises concerns that the Kiwira virus could potentially spread to humans.

Although hantaviruses do not appear to cause disease in humans, their ability to cause febrile illness, a common symptom shared with other infections, may allow their infection to be missed. Therefore, it is essential to improve the development of accurate serological assays that can be used to confirm hantavirus infection.