19 Dec

Nipah Virus and Zoonotic Diseases

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Content

• Introduction
• Why Zoonotic Diseases are fast spreading to humans?

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Nipah Virus

Introduction

• According to WHO Nipah Virus (NiV) infection is a newly emerging zoonosis (a disease that can be transmitted from animals to humans) that can infect both humans and animals.
  •  It is classified as a “highly pathogenic paramyxovirus” and handling it requires the highest grade of facilities called BS-4.
• The natural host of the virus are fruit bats of the Pteropodidae family, Pteropus genus. Humans are generally infected by fruit bat or pigs. Human to human transmission is also known including in the hospital setting.

First identification

• First identified during the outbreak of disease that took place in Kampung Sungai Nipah, Malaysia in 1998. In this case pigs were intermediate hosts. Since, then there have been several outbreaks even without intermediate hosts.
• In India it was first detected in Siliguri in 2001 and Nadia in 2007. This was a spillover of the outbreak in Bangladesh.
• Later in 2018, 19, 21 and again in 2023 it appeared in Kerala.

Why?

• • Kerala has several fruit plantations that host several species of bats.
  • Better health facilities in Kerala may be leading to better detection, surveillance etc., whereas in other states the cases may go undetected.
• Note: In 2018, 21 and 2023, the outbreak occurred in Kozhikode district and in 2019 the outbreak was in Ernakulam district.
• Why only in these districts?
  • Not clear. A 2021 study have found that Nipah virus as found to be in circulation in fruit bats in “many districts” in Kerala.
  • An ongoing national survey in 14 states by NIV Pune found NIPAH virus antibody in 9 states, including Kerala, and the UT of Puducherry.

Symptoms of NiV can be neurological, respiratory and pulmonary. They include:

i. Encephalitis (brain swelling) due to Inflammation of the brain

ii. Confusion, disorientation and even persistent drowsiness

iii. Headache, fever, nausea and dizziness (flu like symptoms)

Fatality: Around 40-70% depending on the local capability for epidemiological surveillance and clinical management.

Prevention (Avoid date palm sap; avoid close contact with NiV Patient; avoid direct contact with
pigs/bats in endemic area)

Treatment / Vaccine

• Intensive Support care (no treatment or vaccine is available)
• According to NCDC (National Centre for Disease Control), Ribavirin, an antiviral, may have a role in reducing mortality among patients with encephalitis caused by NIPAH virus disease.

Why Zoonotic Diseases are fast spreading to humans ?

Introduction

• According to WHO, more than 300 zoonotic diseases have been observed over the past 70 years. It constitute about 60% of all human diseases and 75% of all the Emerging Infectious diseases. The last decade has been worst and have caught the humans unprepared. Some recent examples are that of Ebola, Zika, Nipah, Kyasanur Forest disease, COVID-19 etc.

Why increase in zoonotic diseases?

• Dramatic increase in population and mobility -> Environmental changes , Deforestation etc. -> increase human contact with pathogens.
• Increased demand for animal protein
  • Livestock production is moving closer to towns in the form of poultry farms etc.
• Rise in intense and unsustainable farming
• Increased use and exploitation of wildlife
• Unsustainable utilization of natural resources
• Many Indian villages are located within or around forests
  • Thus, significant number of people interact with forests in their day-to-day lives
• Global Warming
  • Increases the population of insects like ticks that harbour and transfer the virus
• Poor Preparation in terms of infra and human resource
  • Zoonotic diseases become more problematic in countries where health infrastructure is poor (e.g. Ebola in Africa, Zika in South America, Nipah in Asia etc.)
• Lack of awareness especially in rural areas also

Implications

• Health
• Economic losses
  • Death of farm/domesticated animals etc.
  • Negatively hampers tourism of the region.

Way forward: How to deal with increasing infectious zoonotic diseases

• Coping with unprecedented rise in the risk of pandemics and epidemics requires a holistic approach to medicine that treats human health as part of environmental health. We need to be more proactive in restoring wildlife health.
• There is a need of closer monitoring and research into how increasing ecological footprint of humans is affecting health and disease dynamics.
• Operationalising the One Health approach in land-use and sustainable development planning, implementation and monitoring, among other fields.
• Further, there is a need to increase R&D, improve awareness and better health infrastructure facilities to deal with rising cases of zoonotic diseases.
• Incentivize sustainable land management practices and developing alternatives for food security and livelihoods that don’t rely on the destruction of habitats and biodiversity.
• Improving biosecurity and control, identifying key drivers of emerging diseases in animal husbandry and encouraging proven management and zoonotic disease control measures;
• Strengthening capacities among health stakeholders in all countries.

Example Questions
“The diseases currently associated with forests (zoonotic diseases) can, in several ways be seen as a reaction to change in the relationship between humans and forests” Elaborate [10 marks, 150 words