Tuesday, December 11, 2018
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In Focus

Posted at: Jun 4, 2018, 12:45 AM; last updated: Jun 4, 2018, 12:45 AM (IST)HEALTH: THE KILLER NIPAH

Don’t go viral

National commitment at the highest level of the government and comprehensive efforts in partnership with stakeholders, including experts in animal health, are key to tackle emerging viral infections, says Dr Jai Prakash Narain

HUNDRED years ago, 1918 to be precise, the influenza pandemic killed at least 50 million worldwide. This was among the worst disasters in human history.  Even today, influenza is a huge challenge, as are some other viruses. 

Certainly, there have been significant medical achievements in containing viral outbreaks. The past four decades witnessed monumental success in eradicating smallpox and polio. But the threat posed by various viral diseases remains a major concern.  Out of the 18 new viruses, including Nipah, 12 have originated from the animal world. 

The spurt

In fact, the first pandemic of the 21st century was caused by a new Corona virus, which led to SARS (severe acute respiratory syndrome) in 2003. The pandemic HINI influenza virus emerged in humans in April 2009 in Mexico, which was initially associated with pigs, hence called swine flu. It thereafter quickly spread worldwide through human-to-human transmission, including India. 

In addition, 2014 Ebola epidemic in western Africa continued the global attention on viral diseases. This was followed by Zika virus in Brazil causing microcephaly or small head in new borns, and Middle East Respiratory Syndrome, or MERS, caused by Corona virus caused considerable concern and anxiety. 

In May 2018, an outbreak of Nipah was reported in Kozhikode and Malappuram districts of Kerala. Fourteen deaths have so far been reported, including healthcare worker, a 31year-old nurse who was caring for a patient of Nipah.

Similar outbreaks had been reported before from Siliguri (2001) and Nadia districts (2007) in West Bengal. Evidence of human-to-human transmission and a high death rate are some of the alarming developments seen in Nipah outbreaks. There is no vaccine or specific treatment available. Therefore, prevention remains the most critical aspect.

As a preventive measure, those living in affected areas - Kozhikode and Malappuram - or others visiting the area of activity must take precautions and avoid contact with bats and fruits or anything that may have been contaminated with fruit bat urine or saliva. Those caring for patients with suspected or confirmed Nipah infection, including healthcare workers and family members, must follow universal or standard precautions and avoid contact with body fluids of the sick or deceased, including laboratory specimens.

The risk

The major drivers associated with the emergence of new viruses include human encroachment into animal habitat and interface with wildlife. Other factors include urbanisation, deforestation, changes in land use or agricultural practices, or occupational exposure. The disease spread, within the country or beyond, is facilitated by rapid means of travel and wildlife trafficking, a consequence of globalisation. 

The mutation of a virus strain from animals such chicken in H5N1 influenza, making it infectious to humans, is a common cause of new illnesses in humans. 

The caution

The question arises whether we can stop the next outbreak of a viral disease before it happens or reduce its impact? 

Yes, this is possible by strengthening health systems in three ways. First, by establishing a robust surveillance system to keep a close watch on health events, monitor trends and using data so obtained for public health action is needed across various levels of health services. The National Centre for Disease Control (NCDC) in Delhi has the mandate to conduct surveillance through its integrated disease surveillance programme (IDSP) to look for early warning systems and assist states in outbreak investigations.

Second, having an efficient and high quality of national laboratory systems, including networking to facilitate detection through rapid and reliable diagnostics and identifying an etiological agent. 

Third, responding rapidly and effectively to an outbreak and ensuring information flow throughout the health system as well as to the community concerned. Rapid response teams are available at district, state and national levels, to be deployed for outbreak management within 24-48 hours. Emergency operation rooms can be activated for information flow. Health system can ensure access to vaccines and life-saving medications as appropriate. The states need to train and deploy an effective public health workforce, including at least one trained field epidemiologist in each district.

Cross-cutting research to develop new surveillance tools, diagnostic tests, vaccines and therapeutics through basic, translational and applied research must be accelerated. The Indian Council of Medical Research (ICMR) is best placed to assist through its network of institutes such as the National Institute of Virology at Pune and a chain of regional centres. 

Finally, national commitment at the highest level of the government and comprehensive efforts in partnership with various stakeholders, including those in animal health, are key to meet the threat of emerging viral infections now and into the future.

Myth

There is no risk associated with fresh fruits coming from South, including Kerala. While all kind of information is being circulated in social media, no such advisory has been issued by the government.

From Kampung to Kerala

Trail 

  • 1998-Malaysia: The virus was first traced in Kampung Sungai Nipah
  • 2001-Bangladesh: First traced in Meherpur, then occurred annually
  • 2001-India: Two outbreaks in Siliguri, West Bengal
  • 2007-India: Second outbreak in the Nadia district, West Bengal
  • 2018-India: The third outbreak in Kerala on May 19
Virus

  • NiV is a highly pathogenic paramyxovirus
  • Zoonotic, normally occurs in animals, can infect humans 
  • Fruit bats of Pteropus genus are stated to be the natural host 
  • Incubation period varies from 6-21 days
Causes

  • Presumably, pigs get infected after consuming fruits partially eaten by bats 
  • In Bangladesh and India, the outbreaks occurred between December-May
  • Transmission occurs after direct contact with infected bats, pigs or people
  • Transmission due to drinking of raw date palm sap infected with the NiV
  • Close physical contact with infected patients, especially through body fluids
Symptoms

  • Fever, altered mental status, severe weakness and headache
  • Respiratory distress, cough, vomiting, muscle pain, convulsions/diarrhea
  • Severe inflammation of the brain (encephalitis) or respiratory diseases
Diagnosis

  • Enzyme-linked immunosorbent assay (ELISA)
  • Polymerase chain reaction (PCR) assay
  • Virus isolation by cell culture 
Casualties

  • Fatality rate is estimated at 40-75 per cent may go up to 100 per cent 
  • Killed 15 persons in Kerala between May 19 and 31 this year
Prevention

  • Wash hands properly after coming in contact with infected persons/animals
  • Avoid consuming raw date palm sap or toddy
  • Consume only washed fruits 
  • Avoid consuming half-eaten fruits from the ground
  • Avoid entering into abandoned wells 
Treatment 

  • No known treatment or vaccine is available for either people or animals
  • Ribavirin may reducing mortality among patients with encephalitis by NiV
  • Intensive care with treatment of symptoms to manage infected people  (Sources: WHO & National Centre for Disease Control)
SOME VIRAL OUTBREAKS IN INDIA

Zika: On May 15, 2017, the Ministry of Health and Family Welfare reported three cases of Zika virus disease in Bapunagar in Ahmedabad

Chikungunya: February-October 2006, 151 districts in 8 states affected by chikungunya fever. Affected states included Andhra Pradesh, Tamil Nadu, Karnataka, Maharashtra, Gujarat, MP, Kerala and Delhi

Avian influenza: February 2006, agricultural authorities confirmed the country’s first outbreak of highly pathogenic H5N1 avian influenza in poultry. But the Ministry of Health informed WHO that no human cases of H5N1 infection have been detected (Source: WHO)

— The writer is a Senior Visiting Fellow at the University of New South Wales, Sydney

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