What is examples of rodents…..
MICE , GUINEA PIG ,RAT
Transmission of rodent born virus
- Rodent-borne viruses are transmitted from rodents to man by contact with infected body fluids or excretions.
- From Rodent to rodent it is transmitted without participation of arthropod vectors.
Major rodent-borne viruses include:
1.Hantaviruses:
They cause mainly two categories of manifestations like –
ā¢ Hemorrhagic fever with renal syndrome ( caused by Hantaan virus, Dobrava virus, Puumala virus and Seoul virus )
ā¢ Hantavirus pulmonary syndrome (caused by another member, Sin Nombre virus.)
2. Arenaviruses:
ā¢ New world viruses: for examples unin, Machupo, Guanarito and Sabia viruses. They cause South American hemorrhagic fever
ā¢ Old world viruses: for examples Lassa ruses and lymphocytic choriomeningitis viruses.
Hantaviruses
Genus Hantavirus belongs to the family Bunyaviride.
They are spherical, enveloped viruses; contain triple segmented,negative-sense ssRNA
Reservoir:
Rodents are the reservoir of infection, but they do not suffer from the disease.
They harbor virus lifelong and transmit to other rodents horizontally .
Transmission
Transmission to humans occurs by inhaling aerosols generated from rodent excreta like urine, feces and saliva.
Clinical Manifestations
Hantaviruses cause two fatal human diseases these are
Hemorrhagic Fever with Renal Syndrome (HFRS}
It is an acute viral infection, characterized by:
- Interstitial nephritis that leads to renal failure in severe forms of the disease
- Hemorrhagic fever and shock–Several hantaviruses can cause this condition.
- Hantaan and Dobrava viruses cause the severe form of HFRS in Asia, particularly in China, Russia, and Korea, and in Europe (Balkans).
- Seoul virus causes a less severe form of HFRS throughout Eurasia.
- Puumala virus causes a mild form of nephritis called nephropathia epidemica, prevalent in Scandinavia.
Hantavirus Pulmonary Syndrome
- Sin Nombre virus is the agent of hantavirus pulmonary syndrome which is prevalent in America.
- It has caused an outbreak of severe respiratory illness which occurred in the United States in 1993
- The deer mouse (Peromyscus maniculatus) is the primary rodent reservoir.
Arenaviruses
Arenaviruses are pleomorphic, 50-300 nm in size, enveloped with large, club-shaped peplomers and contain a segmented ssRNA {two segments).
Reservoir:
Reservoir is rodents and Along with each virus is associated with a single rodent species .
Transmission:
Humans are infected by direct contact or inhalation of aerosols generated from rodent excreta .
Classification:
Based on RNA sequence differences and geographical distribution, arenaviruses are classified into old world and new world viruses .
Old World Viruses
Lassa fever virus
ā¢lassa virus Cause hemorrhagic fever, pneumonia, cardiac and renal damage,and last one Permanent deafness .
ā¢ If lassa virus infection occur in Pregnancy than Both fetal death (90%) and maternal deaths (30%) can occur especially in third trimester.
ā¢ Treatment: Ribavirin is the drug of choice for Lassa fever.
Lymphocytic choriomeningitis virus (LCM)
ā¢ Human infection (rare): LCM virus causes aseptic meningitis or a mild systemic influenza-like illness in humans.
ā¢ In Fetus: Vertical transmission occurs early in pregnancy following which it can cause hydrocephalus, blindness or even fetal death.
New World Viruses
- They cause South American hemorrhagic fever.
- Various examples include such as- Junin virus ,Machupo virus ,Guanarito virus ,Sabia virus ,Whitewater Arroyo viruses