Originally shared by Deeksha Tare
Picture below: The flat-faced fruit bat Artibeus planirostris.
Bats to blame
Bats, already known culprits for viruses like Nipah, Hendra, and other coronaviruses, filoviruses, and lyssaviruses, have now been found to harbor Influenza viruses of a novel subtype. Scientists have found these Influenza viruses in Peruvian flat-faced fruit bats (Artibeus planirostris) and yellow-shouldered bats from Guatemala. Thus, there are yet another Mammalian hosts for this respiratory virus.
The two subtypes
The Influenza virus isolated from the Guatemala bats was classified in the subtype H17N10. Whereas the Peruvian viruses, being somewhat related, but vastly diverse from H17N10, have been classified as belonging to the H18N11 subtype. Its HA and NA genes being more genetically different (nucleotide sequence identity of 48.7–62.3%).
The surface proteins
♦ HA- The Hemagglutinin protein of the Peru virus bears only 49.1% similarity to the existing HA proteins of other subtypes. That is why it warrants a separate subtype of its own- H18.
The bat H18 HA does not recognize sialic acid receptors (which is the receptor in case of all Influenza viruses), and its receptor remains to be defined.
♦NA- The Neuraminidase protein too, bears only 29.6% identity with all the other NA subtypes. And hence it has been designated as N11. It is so different from the other NAs that the authors refer to it as the NA-like (NAL) protein.
In spite of the vast difference in sequence, structurally, the N11 is quite similar to common NAs.
♦ A high frequency of antibodies is consistent with widespread circulation of these viruses in bat populations from the Americas.
♦ Bat influenza HA and/or NAL mediate host cell entry and release via different receptors compared to other influenza viruses..
♦ Attempts to propagate this virus in mammalian and avian cell cultures have been unsuccessful.
♦ These influenza viruses have evolved in bats for an extended period of time.
The present study is another reminder of the widely transient nature of Influenza viruses. Their discovery in different hosts and their constantly mutating nature may be indicative of the possibility of a species jump.
Whatever the scenario may be, this unpredictable virus is sure going to keep scientists on their toes!
Yet another post for ScienceSunday . Tagging Rajini Rao Chad Haney Buddhini Samarasinghe Allison Sekuler and Robby Bowles .
(Via Kirk Douglas on #linkedin )