Published in IJCP June 2019
From the Desk of Group Editor in Chief
Nipah Emerges Again in Kerala: Nipah Virus Update
July 08, 2019 | Dr KK Aggarwal

On June 4, the Kerala Health Minister confirmed that a 23-year-old college student admitted to a hospital in Kochi had been infected with the Nipah virus. The results of blood samples of the student, which were tested at the National Institute of Virology (NIV) in Pune confirmed Nipah. Earlier, blood samples examined at two virology institutes - Manipal Institute of Virology and Kerala Institute of Virology and Infectious Diseases - had indicated Nipah.

It was around the same time last year, when the Nipah outbreak was reported from two districts of Kerala - Kozhikode and Malappuram. The Indian Council of Medical Research (ICMR) had then confirmed that fruit bats were the primary source of the virus that killed 17 persons in the two districts. In 2015 and again last year, the World Health Organization (WHO) had cautioned about Nipah as one among eight emerging pathogens likely to cause severe outbreaks in the near future, and for which few or no medical countermeasures exist.

All about Nipah virus infection

  • The Nipah virus infection is a newly emerging zoonotic disease that takes its name from Sungai Nipah, the Malaysian village where it was first identified in 1998.
  • Nipah virus infection is a notifiable disease.
  • There is no National Program for Surveillance of Nipah virus. It is a part of Integrated Disease Surveillance Program (IDSP).
  • Nipah outbreaks have been also reported in India: Siliguri outbreak in 2001: 45 deaths, Nadia-West Bengal outbreak in 2007: 5 deaths, Kerala outbreak in 2018: 17 deaths and Kerala 4th June 2019: 1 case.
  • Agent: Nipah virus is a highly pathogenic paramyxovirus.
  • Natural reservoir: Large fruit bats of Pteropus genus are the natural reservoirs of Nipah virus. Presumably, pigs may become infected after consumption of partially bat eaten fruits that are dropped in pigsties.
  • Seasonality: All of the Nipah virus outbreaks have occurred during the months of winter to spring (December-May).
  • Incubation period: 6-21 days.
  • Mode of transmission: Direct contact with infected bats, infected pigs or from other Nipah virus infected people, especially by contact with body fluids; in hospital setting if appropriate personal protective equipments or standard infection control measures are not used; drinking of raw date palm sap or toddy contaminated with Nipah virus or through infected bat secretions during fruit tree climbing, eating/handling contaminated fallen fruits.
  • Nipah is not an airborne infection; the virus can persist on surfaces. Infection can spread through droplets and objects contaminated by secretions (urine, saliva, etc.) of infected animals or humans (fomite-borne Nipah virus transmission).
  • Clinical features: Initial symptoms include fever, vomiting and severe headaches; some patients may have acute respiratory syndrome. Disorientation, drowsiness and mental confusion appear later on. Coma and death may occur within a day or two.
  • Case-fatality rate: 40-75%; however, this rate can vary by outbreak and can be up to 100%.
  • Diagnosis: Identification of Nipah virus RNA by polymerase chain reaction (PCR) from respiratory secretions, urine or cerebrospinal fluid and/or isolation of Nipah virus from respiratory secretions, urine or cerebrospinal fluid. In India, testing facility is available at NIV, Pune and NIV Alleppey.
  • Treatment: Currently there is no known treatment or vaccine available for either people or animals. Intensive supportive care (bed rest, fluids) with symptomatic treatment is the main approach to managing the infection in people. Early treatment with ribavirin, an antiviral, may have a role in reducing mortality among patients with encephalitis caused by Nipah virus disease.
  • Isolation: The infected persons are kept in isolation in a room in the house or in isolation wards in designated hospital/s to prevent spread of the virus. Standard infection control protocol must be strictly adhered to. After the suspected case is transferred to the hospital, the room must be disinfected in accordance with prescribed SOPs by Lysol/5% sodium hypochlorite or any other disinfectant.
  • Prevention: Avoid exposure and contact with infected persons and animals, practice hand hygiene and use appropriate personal protective equipment, avoid consuming half eaten fruits lying on the ground, avoid abandoned caves and wells, avoid consuming raw date palm sap or toddy, follow government advisory when handling dead bodies of the infected persons.

Contact tracing

A contact is any person who has a history of contact with a case (person who is laboratory confirmed). Contact tracing must be done up to 21 days from the last case in the area within 5 km radius from the periphery of the affected area.

  • Each worker or person responsible for contact tracing should:
  • Enlist all the contacts for tracing.
  • Distribute triple layer surgical masks to each household and keep sufficient stock (but avoid misuse/unnecessary use, as as it may create fear/panic).
  • IEC on Nipah virus infection, symptoms and importance of contact tracing and home quarantine/isolation.
  • Give his telephone number and number of control room/nearest health facility.
  • Have location and details of dedicated ambulance and availability of disinfectant.
  • The case can transmit the disease from the development of first symptoms (which may be cough and/or fever with headache) till 21 days have passed from the last contact.
  • During contact tracing, the person should be visited daily and/or enquired about telephonically about any fever, cough, headache (and/or other symptoms like altered sensorium, shortness of breath, etc.), or keeping a self-watch on developments of symptoms. If a contact develops symptoms, then he/she becomes a suspect case and should:
  • Immediately wear a triple layer mask and put him under self-isolation (means should not go near/maintain a distance of around 3 m to any other person).
  • Inform concerned health worker (and or nearby doctor) and not to move by himself (unless there is delay and symptoms are getting worse).
  • Dedicated ambulance (with driver and accompanying health staff having full protective gears) to be used for transporting all such suspects.
  • Enlist all possible contacts since the time he/she has developed symptoms and inform health worker.
  • Health worker has to put all such persons in contact list for further doing contact tracing for 21 days, since the time of last contact with a person having symptoms or till the time, the person's test for Nipah virus comes negative.
  • All households and close contacts of a suspect case should be under home quarantine till the time test results of symptomatic comes negative. If test result comes positive then all such persons become contacts and have to be put under contact tracing for next 21 days.
  • The area/district/state can be declared free after 42 days from the date of last positive case reported from the district/state.

Time for action and not reaction

  • Public health problems such as Nipah require a multilateral effort. So, any action taken involves education along with participation of all stakeholders, including the general public.
  • A district, state, national and international plan of action should be in place.
  • The public health information should include standard relevant messages for everyone and innovations in research. This information should include all Dos and Don’ts.
  • There should be a uniform protocol for all systems of medicine.
  • Doctors from all systems of medicine should refrain from any claims of cure. If they possess any such cure, it should be first submitted to the government for review.
  • The primary source should be traced - pig, bat or human.
  • There should be guidelines and effective system for contact tracing and their management.
  • There should be a standard protocol for case handlers and probable case spreaders.
  • National surveillance in all cases of encephalitis for the cause, Nipah or any other.
  • There should be a protocol for spread of encephalitis to contacts.
  • A government advisory should be issued for handling of dead bodies of people who die due to the infection.
  • The role of police, military and media should be well-defined.

Source: National Center for Disease Control, Recommended Community level Public Health Measures for Nipah virus infection; Nipah FAQs.