Hantavirus

Hantaviruses

There are over 20 different sero /genotypes of Hantaviruses.

Rodents are the natural hosts. Each hantavirus is carried by a specific rodent species.

Hantaviruses cause two distinctly known problems. The hantavirus from America (the new world) is associated with a Hantavirus Pulmonary Syndrome, and from Asia and Europe (the old world) is associated with a Hemorrhagic fever with Renal Failure.

Person to person transmission is not common however epidemiological studies in Southern America revealed that person to person transmission can occur with Andes virus (ANDV).

Pathology

Increase in capillary permeability leading to hypotension.

The mechanism for thrombocytopenia is not known.

Pathogenic Hantaviruses and their geographical distributions

Puumala (PUU) - Northern and Central Europe

Dobrava (DOB) - Eastern and Central Europe

Sin Nombre virus (SN) – North America

Andes virus (AND) - South Americas

Seoul virus (SEO) – South East Asia and world wide

Haantana virus (HTN) - Asia

Clinical Presentations

The incubation period is 2 to 4 weeks.

The clinical presentations range between asymptomatic infection to severe illness or even death.

People who have exposure to urine, saliva and faeces of infected rodents are at risk of infection

Immunity is life long for specific hantavirus however it is not known whether infection with one hantavirus type will protect from another type of hantavirus.

I. Hantavirus Pulmonary Syndrome

It is caused by the hantavirus from the New world (North and South America).

Renal involvement is not marked.

No hemorrhagic manifestation.

1. Sin Nombre

Mortality is high (40-50%.)

Cardiopulmonary problems- respiratory insufficiency.

2. Andes virus

In some endemic areas the seroprevalence rate could be as high as 12 %.

Mortality rate is above 40 %.

Person to person transmission has been documented.

II. Hemorrhagic Fever with Renal Syndrome (HFRS)

This is caused by hantaviruses from Old world (Europe and Asia).

Fever, headache, nausea, vomiting and abdominal pain are common manifestations.

Hypotension-

Bleeding- petechial rash, haematuria, haematemesis

Blurred vision (due to lens thickening)

Acute renal failure- oligouria

Complications

Glomerulonepheritis

Panhypopituitarism

1. Puumala (nephropathia epidermica)

It is associated with mild illness.

Shock not common

Case fatality rate is less than 0.2 %.

2. Dobrava

Case fatality rate is around 10 %.

Haemorrhagic complication is common.

3. Hantana

Causes the sever form of HFRS

Conjunctival injection is common

4. Seoul

Moderate form of HFRS