Lassa virus: what’s in a name?

Posted onAuthorIan M Mackay, PhD (EIC)

UPDATED

Just a little post to share some stuff I’ve learned while writing things about stuff.

Lassa virus. It can be written in shorthand as LASV. The virus causes Lassa fever (LF), a viral haemorrhagic fever (VHF).

The name Lassa fever derives from its discovery associated with illnesses in three healthcare workers (two were fatal) from hospitals in the Nigerian town of Lassa (first case) and the city of Jos (remaining cases) in 1969.[3,4] The 2nd and 3rd cases were the result of human-to-human transmissions via contact between infected patient fluids/tissues during care/autopsy.[4]

The 1970 publication described the disease as “It is likely primarily a disease of some nonhuman form of animal life, and its severity suggests that it is not well-adapted to the human host”.[4] We now know LASV travels in its natural host, the Natal multimammate rat (Mastomys natalensis).[5] Other rodent species (Rattus rattus and Mus Musculus) have also tested positive for LASV RNA using RT-PCR methods.[6; Table above] These species were much less often positive, but occurred in far greater numbers than Mastomys natalensis in a study from Edo, Delta and Bayelsa States of Nigeria.[6]

 

Table 2 from Prevalence of Lassa virus among rodents trapped in three South-South States of Nigeria.[6] https://www.ncbi.nlm.nih.gov/pubmed/28748835

But of course there are structures and boxes and lists and conventions around any virus name.

 

For LASV, they are organised into levels which go a little something like what follows, according to the crew at the International Committee on Taxonomy of Viruses (ICTV; they really needed Cisco Ramon to create  them a sexy acronym [1])…..

Strains: call ’em what you like – it’s cowboys, chaos and anarchy at this level.
Species: Lassa mammarenavirus
Genus: Mammarenavirus
Family: Arenaviridae
Just for interest, the “Mamma” bit delineates these mammalian infecting viruses from those assigned to the genus Reptarenavirus, which infect…..reptiles. Except for that 3rd genus, Hartmanivirus.[2] It’s named after the Haartman Institute snake virus, HISV. Now HISssssssV my friends, is a Cisco-worthy acronym. Also a snake host. Whatevs!

References….

  1. Arenaviridae, ICTV
    https://talk.ictvonline.org/ictv-reports/ictv_9th_report/negative-sense-rna-viruses-2011/w/negrna_viruses/203/arenaviridae.
  2. Past, present, and future of arenavirus taxonomy
    https://link.springer.com/article/10.1007/s00705-015-2418-y
  3. Review of Lassa fever, an emerging old world haemorrhagic viral disease in sub-Saharan Africa
    https://www.ajol.info/index.php/ajcem/article/view/140149
  4. Lassa fever, a new virus disease of man from West Africa. I. Clinical description and pathological findings
    http://www.ajtmh.org/content/journals/10.4269/ajtmh.1970.19.670
  5. Movement Patterns of Small Rodents in Lassa Fever-Endemic Villages in Guinea.
    https://www.ncbi.nlm.nih.gov/pubmed/29572697
  6. Prevalence of Lassa virus among rodents trapped in three South-South States of Nigeria
    https://www.ncbi.nlm.nih.gov/pubmed/28748835

Updates…

  • 09APR2018 – added more historic detail, improved title.

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