Rhododendrons carpet Darjeeling and Sikkim Himalayas (GS Paper 3, Environment)
Why in news?
- The Darjeeling and Sikkim Himalayas are home to more than one-third of all types of rhododendrons found in India, reveals the latest publication of the Botanical Survey of India (BSI).
- The publication, titled, ‘Rhododendrons of Sikkim and Darjeeling Himalaya — An Illustrated Account’, lists 45 taxa of rhododendrons (36 species, one subspecies, two variety and seven natural hybrids).
Key Findings:
- There are 132 taxa (80 species, 25 subspecies and 27 varieties) of rhododendrons found in India.
- Of the 45 taxa recorded in the publication, 24 are found in the Darjeeling Himalayas and 44 in the Sikkim Himalayas.
- Darjeeling and Sikkim Himalayas comprise only 0.3% of India’s geographical area but the region is home to one-third (34%) of all rhododendron types. This highlights the ecological significance of the region as far as an indicator species like rhododendron is concernednd.
Under threat:
- Of the 45 taxa documented by the BSI, five are facing a high threat due to anthropological pressures and climate change, according to scientists.
- Rhododendron edgeworthii, with white campanulate flowers, recorded a huge habitat decline in both Darjeeling and Sikkim.
- Rhododendron niveum, with big purple flowers, found in the Lachung area of north Sikkim is facing threats from rampant construction.
- Rhododendron baileyi, Rhododendron lindleyi and Rhododendron maddenii are also under threat.
Climate Change:
- Rhododendron, meaning rose tree in Greek, is considered an indicator species for climate change.
- The flowering season for rhododendrons starts in March and continues till May. However, recently, flowering was found to begin as early as in January for some species.
Background:
- Rhododendrons have a prominent place in the country’s botanical history. They were first recorded by Captain Hardwick in Jammu and Kashmir in 1776 where he spotted Rhododendron arboreum.
- However, it was a visit by the British botanist Joseph D. Hooker to Sikkim between 1848 and 1850 that revealed the rhododendron wealth of the Sikkim and Darjeeling Himalayas.
- The first species Rhododendron from northeast India, Rhododendron dalhousiae was reported from Sikkim by Hooker in 1848 in his book The Rhododendrons of Sikkim Himalaya.
Is there a need for an extra dose of polio?
(GS Paper 2, Health)
Why in news?
- Recently, the West Bengal government announced that it was introducing an additional dose of injectable polio vaccine as part of the Universal Immunisation Programme (UIP) for children.
- The State, considered among high risk areas for polio, announced that this dose will be given at nine months, in addition to the existing doses in the current UIP.
Details:
- Additionally, two Polio Immunisation days are observed in the country each year and in some States, there are sub-national immunisation days, involving children under five years of age.
- An additional dose of inactivated poliovirus (IPV) at nine months will protect against any polio thereafter Vaccine Associated Paralytic Polio or Vaccine Derived Polioviruse.
What is polio?
- Poliovirus can invade the central nervous system and as it multiplies, destroy the nerve cells that activate muscles, causing irreversible paralysis in hours.
- There are three types of polio virus serotypes: types 1, 2 and 3. According to the India Polio Learning Exchange (along with UNICEF), of those paralysed, 5-10% die when their breathing muscles become immobilised.
- There is no cure for polio, but there are safe, effective vaccines which, given multiple times, protect a child for life. Polio held the world in a bind of fear until Jonas Salk developed the first polio vaccine.
- Later, Albert Sabin made a ‘live’ polio vaccine that could be administered orally which became the tool of the trade, especially for nations carrying out mass immunisation campaigns, including India.
How did India achieve its polio-free status?
- In 2012, the WHO removed India from the list of endemic countries.
- Seen as a massive achievement in public health, the campaign had begun years ago. While Rotary International launched its polio eradication campaign, Polio Plus, in 1985, it was in 1986 that it provided a $2.6 million grant to Tamil Nadu for a pilot polio vaccination campaign.
- In 1995, the Union government announced the first National Polio Immunisation Day.
- As per the India Polio Learning Exchange portal, the last case of poliovirus type 2 case was recorded in India in October 1999 at Aligarh, Uttar Pradesh; the last case of poliovirus type 3 case was on October 22, 2010, at Pakur, Jharkhand; and the last case of poliovirus type 1 case was recorded on January 13, 2011, at Howrah, West Bengal.
- As of October 2022, the WHO said only two countries worldwide remain with indigenous transmission of wild poliovirus type 1 (WPV1) — Afghanistan and Pakistan.
- It also recorded that so far, 33 countries have outbreaks of variant polioviruses, such as in the U.K., the U.S., Israel and Malawi.
What was the recent global polio crisis?
- Genetic variants of vaccine poliovirus type 2, imported from an unknown source, were detected in waste waters in Jerusalem, London and New York in early 2022.
- The wild poliovirus type 2 was globally eradicated in 1999, but vaccine virus type 2 continued for 16 more years; routine use of the vaccine was discontinued in 2016 and reintroduced occasionally on purpose.
- As an unintended consequence, type 2 vaccine virus variants (circulating vaccine-derived polioviruses) that mimic wild viruses’ contagiousness and neurovirulence, have been emerging and spreading.
Way Forward:
- The recent events have shown how dramatically and rapidly global progress can unwind if the pressure is not maintained to vaccinate children.
- In November, at the meeting of the India Expert Advisory Group for polio eradication, participants discussed how India continues to maintain high population immunity, risk mitigation from polio viruses including containment and transitioning of polio networks.
- Their suggestions will guide revised policy changes to ensure that India remains polio free.
Why environmental surveillance for avian influenza is vital
(GS Paper 2, Health)
Why in news?
- The world’s largest northern gannet (a bird) colony at the Bass Rock, an island off the coast of North Berwick, Scotland has been recently decimated by avian influenza (H5N1) or bird flu.
- H5N1 has caused unprecedented loss of tens of thousands of birds in the U.K.
Other instances:
- The impact of this disease is very serious for bird conservationists. Recently, intra-mammal transmission of H5N1 in captivity in mink farms was recorded, posing a bigger concern in relation to zoonotic potential.
- In India, the latest major avian flu outbreak in2020-2021 swept through many States causing mass mortality of wild birds which brought the concerns on the lack of active surveillance to the forefront, and how wetland and waterfowl habitats at the interface of poultry need to be monitored.
Risk in India:
- While the avian flu outbreaks coincide with the peak migratory season leading to post-outbreak surveillance and culling, there are also reports of outbreaks in the off-season suggesting endemic transmission within the poultry sector.
- India is the fastest growing egg producer in the world, but unlike in Europe, poultry birds here are not vaccinated against flu.
- Furthermore, the farms with a diversity of animals or in the vicinity of nearby wetlands increases the potential for the viruses to undergo reassortment that can potentially generate more virulent strains H5N1 or H7N9 which could then infect humans.
- Despite this potential, there is no active surveillance in the poultry sector. There may be no efficient human-to-human transmission mechanism yet, however, the risk cannot be ruled out as the virus continues to evolve.
Environmental surveillance:
- Wastewater-based epidemiology or pathogen surveillance has become an integral component of environmental surveillance providing near real-time information on health and community exposure to pathogens. While environmental surveillance is not a new concept and has been used widely for monitoring several pathogens, it offers an excellent tool.
- Birds infected with avian influenza virus shed large quantities of virus in their faeces, saliva and nasal secretions for about a week.
- Wild aquatic birds in the Orders Anseriformes and Charadriiformesare the primordial reservoir for the virus. The transmission of the virus within these wild bird populations is dependent on faecal/oral transmission via contaminated water.
Surveillance network:
- Avian influenza viruses have been isolated from unconcentrated water in lakes in the U.S., Canada and China. Recurrent infections of animal hosts with the virus have posed a persistent threat.
- Having a large-scale influenza A virus surveillance network in place across multiple sites is crucial for improving our understanding on the diversity, seasonal and geographical distributions of the virus in environments associated with poultry and wild birds.
- Avian influenza viruses can remain viable for extended periods of time in surface water and carcasses, suggesting that lakes and wetlands can act as environmental reservoirs at variable temperatures for several months.
- In a study in Hong Kong, an H3N2 virus was isolated from faeces and pond water every month during a one-year period, and the maintenance of this virus was proposed to be dependent on environmental persistence and the continued introduction of susceptible ducklings.
- Domestic ducks are recognised as an important reservoir for H5N1.
Way Forward:
- Currently, virus surveillance is reactive and relies on sampling dead birds. Environmental surveillance would be a great non-invasive tool that can be done without disturbing the birds and can be used to obtain both host and viral genetic material.
- Most importantly, environmental surveillance should be complemented with effective carcass collection and testing, and better biosecurity on poultry farms to improve preparedness and response in the future.
