Hantavirus Diseases

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Hantavirus Diseases 

Nature of the disease
Hantavirus (HTV) Infections are zoonoses due to the transmission, by rodents, of a virus of the Bunyaviridae family. There are many different strains of viruses causing two different syndromes, Hantavirus Pulmonary Syndrome (HPS) and Hemorrhagic Fever with Renal Syndrome (HFRS). These diseases can lead to high fatality rate and there have been an increasing number of outbreaks in the last few years.
Classification
OIE-unclassified, SPC list D disease, high level of biosecurity
Susceptible species
HTV are primarily considered to be transmitted by rodents of the Muridae family (from which deer mice, white-footed mice, harvest mice, rats are common involved) but it has been isolated from other mammals such as bats and cats and even birds without establishing their epidemiological role.

Humans seem to be the only specie to develop the disease.

Distribution
Humans cases of HPS occur in Northern and Southern America and in Western and Eastern Europe.

Humans cases of HFRS occur in Asia.

Clinical signs 
So far, no clinical signs of the disease have been described in animals.

In humans clinical signs of the disease include depending on the syndrome: abdominal pain, fever, flu-like syndrome, hemorrhages, headache, kidney failure, pulmonary oedema, shock.

Post-mortem findings 
No lesions in animals
Differential diagnosis 
No clinical signs in animals
Specimens required for diagnosis 
Identification of the virus is made by ELSIA (enzyme-linked immunoassay), IHC (immuno-histochemistry) and PCR. However contamination risks by the virus make the specimen collection very hazardous and should be only carried out by skilled technicians.
Transmission   
Infected material from rodents are: blood, saliva, urine, faeces. The most common way of transmission is by aerosol from contaminated urine. Other means include bites (rare),

Oral contact or consumption of contaminated material (food, hands...) have been suspected but not confirmed. 

The role of cat ownership has been stressed as a risk factor in Korea, probably du to their habit of bringing rodents (prey) near households. 

Risk of introduction   
According to the modality of transmission, risk of introduction are confined to introduction of infected rodents from America or Asia.
Control / vaccines  
There is no vaccine for Hantaviruses infections nor any specific treatments.

Control is based on rodent extermination, particularly when the El-Nino climatic phenomena occurs as it produces favourable conditions for rodent breeding.  

References
  • Promed
  • Center for Disease Control and Prevention (CDC)
  • Hantavirus website
  • CLEMENT J, Mc KENNA P, Van der GROEN G, VAHERI, and PETERS CJ (1998), Hantaviruses In Zoonoses, ed by SR PALMER, Lord SOULSEY and D.I.H. SIMPSON, Oxford University Press, Bath Press, Avon, 1998, p.331-351