Deadly infection preventable, not yet curable

KERALA recently witnessed an alarming outbreak of disease epidemic caused by the Nipah virus, claiming more than 16 deaths in a short span of around 20 days. Nipah virus is a zoonotic pathogen and RNA virus of genus Henipa virus, previously reported to be transmitted to humans through bats and pigs. 

Manifestation

Its symptoms include fever, headache, dizziness and vomiting that develop into severe encephalitis. The incubation period in humans range from four days to two weeks. 

The brain is the most severely affected organ and the virus is commonly identified in lungs and kidneys.   

Patient secretions, especially respiratory secretions like sputum and nose discharges, are considered to be the main driver for patient-to-patient transmission.

Detection

Molecular tests (both qPCR and next-generation sequencing) are the most rapid and accurate tools available to confirm the virus infection. Acute-phase serum, CSF (cerebrospinal fluid), throat swabs, saliva, and urine can be used for these tests. There is also an IgM ELISA test based on the whole viral antigen. Live virus isolation should be conducted in a high-level biocontainment facility (bio-safety level IV).

Treatment

Currently, no targeted treatments that can be effective in curing the infection are available. The management is limited to supportive care. Ribavirin has been shown to be effective against the viruses in lab experiments, but human investigations to date have been inconclusive and the clinical usefulness of Ribavirin remains uncertain. Similarly, monoclonal antibodies have also been developed that have shown beneficial results during animal experiments.

Control

Contact tracing, aggressive monitoring and quarantining of suspect cases are the effective forms of infection control and containment. These have been appropriately implemented by responsible government agencies responding to this outbreak in Kerala. 

Awareness efforts combined with preventive measures appear to be effective. Measures to prevent Nipah viral infections also include keeping fruit bats away from pigs and avoiding drinking unpasteurised fruit juices and washing, peeling and/or cooking all fruits thoroughly before eating is also a must. The use of universal precautions and appropriate gloves and masks or face shield are sufficient to limit the spread of Nipah virus from patients to their caretakers.

Effective healthcare policies, infection control measures and regular surveillance for viral cultures should be instituted by the government to effectively prevent the spread of the infection. There are lessons to be learned from the Malaysian government, which has effectively quarantined and prevented Nipah for 19 years. 

The vaccine

There are several forms of recombinant vaccines that have been proven to be effective in animal models. These include a recombinant G-protein-based vaccine and viral vector-delivered vaccines. The recombinant G-protein vaccine has been licensed for use in horses in Australia.

—  The writer is Senior Medical Administrator at the Amrita Institute of Medical Sciences, Kochi