Arenaviruses (Bunyavirales Order)

Question 1

Lassa

Answer 1

Family: Arenaviridae

Segmented (-)ssRNA enveloped virus

Baltimore: V

Reservoir: Mastomys multimammate rodent

Epidemiology: Nigeria, Ghana, Sierra Leone, Liberia, Guinea

Incubation: 7-21 days

80% asymptomatic infections. VHF, encephalitis, SNHL.

Mortality: 1%

Diagnosis: RIPL RT-PCR

Treatment: Ribavirin early in course of illness.

No vaccines

Avoid sex for 3 months - infectious semen & urine

Question 2

Lujo

Answer 2

Family: Arenaviridae

Segmented (-)ss RNA

Baltimore: V

Epidemiology: Zambia - Lusaka

Incubation: 9-13 days

Clinical: VHF + MODS. Very similar to severe Lassa.

Mortality: 80%

Question 3

LCMV

Answer 3

Family: Arenaviridae
Genus: Mammarenavirus

Segmented Enveloped (-)ssRNA

Baltimore: V

Reservoir: Mus domesticus & Mus musculus - mice

Worldwide distribution. Seroprevalence unclear.

Incubation: 6-20 days.

Clinical: 1/3rd asymptomatic. Non specific febrile illness. Severe hepatitis + MODS in immunocompromised.

IUD & severe malformation in pregnancy.

Diagnostics: No serology or PCR in the UK - RT-PCR & EIA in the US.

Treatment: Ribavirin, Favipiravir

Question 4

Arenaviruses list

Answer 4

Old world haemorrhagic:

Lassa
Lujo
LCMV

New world haemorrhagic:
Junin
Guanarito
Chapare
Punta Toro
Sabia
Machupo
Whitewater Arroyo (USA)

Question 5

Ambisense RNA

Answer 5

SEE IMAGE IN ALBUM

Arenaviridae has ambisense minus ssRNA genome. The single strand has both plus and minus polarity at 5’ and 3’ end respectively. The strand carries its RdRp with it.

The RdRp will form the mRNA from the minus polarity which carries codes for proteins to construct the antigenome. The antigenome will then get transcribed to make the mRNA for plus polarity half of the genome and replication continues

So it’s genome to mRNA to proteins to antigenome to mRNA

Question 6

Ambisense RNA

Answer 6

SEE IMAGE IN ALBUM

Arenaviridae has ambisense minus ssRNA genome. The single strand has both plus and minus polarity at 5’ and 3’ end respectively. The strand carries its RdRp with it.

The RdRp will form the mRNA from the minus polarity which carries codes for proteins to construct the antigenome. The antigenome will then get transcribed to make the mRNA for plus polarity half of the genome and replication continues

So it’s genome to mRNA to proteins to antigenome to mRNA