Arenavirus Report

ARENAVIRUSESGrace G. Doromal MLS III – A

ARENAVIRUS

CLASSIFICATION Family : Arenaviridae Genus: Arenavirus Subgroup: A) LCM-LASV Complex (Old World

Arenaviruses) B) Tacaribe Complex (New World

Arenaviruses)

MORPHOLOGY Pleomorphic, enveloped viruses with large,

club-shaped peplomers, ranging from 50 – 300 nm in diameter

Genome Double-segmented, circular, single- stranded

RNA that is negative sense and ambisense and is 10- 14 kb in total size

Rodent-borne pathogens Important cause of viral hemorrhagic fever Host cell ribosomes present in the viral

particles are responsible for the “sandy” appearance under the electron microscope

ARENAVIRUS

REPLICATION

REPLICATION

Virus attaches to receptor of the membrane of the host cell and is endocytosed into vesicles

Fusion and release of virion contents in the cytoplasm

Viral mRNAs are capped in the cytoplasm Sequential transcription and translation

occurs Replication starts when enough

nucleoprotein is present to encapsidate neo-synthesized genomes

The ribonucleocapsid interacts with the Z-protein

REPLICATION The virus buds from the plasma membrane,

incorporating host lipids into the virus membrane.

Host cells remain intact. Virus is released from host cell by budding through the cell membrane and gain an envelope. Virus is released from host cell without causing death.

PATHOGENESIS Old World Virus

Lassa Fever Virus Lymphocytic Choriomeningitidis Virus

New World Virus South American Hemorrhagic Fevers

Junin Hemorrhagic Fever Virus Machupo Hemorrhagic Fever Virus Guanarito virus Sabia virus

LASSA FEVER Highly virulent with mortality rate of about 15

% for patients hospitalized with Lassa fever Incubation period: 1-3 weeks from time of

exposure House rat ( Mastomys natalensis ) is the

principal rodent reservoir of Lassa virus The virus can be transmitted through direct

contact with the mouse droppings It may also spread through person-to-person

when an individual comes into contact with the virus in the blood, tissue, secretions or excretions of an individual with the Lassa fever

LASSA FEVERSigns and Symptoms

General weakness and malaise, high fever Sore throat, headache, back, chest, side or

abdominal pain, conjunctivitis, nausea and vomiting, diarrhea, cough

Death

LASSA FEVER

LYMPHOCYTIC CHORIOMENINGITIS Its vector is the wild house mouse Mus

musculus LCM is occasionally transmitted to humans

via mouse droppings. It can be transmitted from mother to fetus.

Incubation period is usually1 -2 weeks, and the illness lasts for 1 – 3 weeks

LCM in humans is an acute disease manifested by aseptic meningitis or a mild systemic influenza-like illness.

LYMPHOCYTIC CHORIOMENINGITIS Signs and Symptoms

fever, stiff neck, malaise, anorexia (lack of appetite), muscle aches, headache, nausea, and vomiting. Symptoms occur 1–2 weeks after exposure.

SOUTH AMERICAN HEMORRHAGIC FEVER Junin Hemorrhagic Fever

Argentine Hemorrhagic Fever Reservoir rodent: Calomys musculinus Human exposure to Junin virus is believed to occur

mainly through inhalation of aerosolized body fluids (blood, saliva) or excretions (urine, faeces) of infected rodents, typically during agricultural. Transmission can also occur via contact of skin lesions to infected rodent secretions and/or excretions.

Incubation Period: Usually 6 to 14 days, but in extreme cases it can range from 5 to 21 days

Transmission through human-to-human is rare; however, nosocomial outbreaks can occur via spread from highly viraemic patients

SOUTH AMERICAN HEMORRHAGIC FEVER Machupo Hemorrhagic Fever

Bolivian Hemorrhagic Fever Reservoir rodent: Calomys callosus Infected animals are asymptomatic and shed the

virus in their excreta, thereby infecting humans. The virus is spread to humans through aerosolized excreta of the rodent, it could be food-borne, or direct contact with the virus particles

The infection has slow onset with fever, malaise, headache and muscular pains. Petechiae on the upper body and bleeding from the nose and gums are observed

SOUTH AMERICAN HEMORRHAGIC FEVER Guanarito Virus

Venezuelan Hemorrhagic Fever Reservoir rodent: Zygodontomys brevicauda Mortality rate of about 33% The virus is spread mostly by inhalation of

aerosolized droplets of saliva, respiratory scretions, urine, or blood from infected rodents

It causes fever and malaise followed by hemorrhagic manifestations ( bleeding ) and convulsions

LABORATORY DIAGNOSIS Cell Culture

Vero Cells Immunohistochemistry

Detect viral antigens in tissues Reverse Transcription- Polymerase Chain

Reaction Detect viral sequences

Serologic Test ELISA IFA

Detect IgM and IgG antibodies