- Zoonosis is any disease that jumps from animals to humans
- COVID-19, Nipah virus, SARS, MERS are some of the zoonotic diseases
- The outbreak of diseases is linked to environmental destruction: Experts
New Delhi: Around nine years ago, David Quammen, Author, Spillover: Animal Infections & The Next Human Pandemic had predicted a zoonotic in his book. Zoonotic diseases or zoonosis refers to any infection or disease that jumps from a non-human/ animal to humans. In 2019, the world witnessed the outbreak of SARS-CoV-2 that causes COVID-19 disease. However, COVID-19 is not the first zoonotic disease outbreak; from Ebola, Severe acute respiratory syndrome (SARS), Middle East respiratory syndrome (MERS), to HIV, Swine Flu, Lyme disease, Rift Valley fever and others, there have been multiple outbreaks and all are zoonotic diseases. None as big as the COVID-19 pandemic the world is grappling with, but these outbreaks are an ominous sign. According to the United Nations Environment Programme (UNEP), zoonotic diseases are interlinked with ecosystem and in the recent past, human activities have destroyed many ecosystems that have resulted in the outbreak of numerous diseases and pandemics.
Urging the need to protect the ecosystem and in turn ourselves, Chandra Bhushan, CEO, International Forum for Environment, Sustainability and Technology (iFOREST) said,
I am afraid that COVID-19 is not going to be the last pandemic that humanity is going to face. In 20 years of the 21st century, we have already had three pandemics whereas in the 19th century we had just one major pandemic. So, the frequency of pandemics is increasing and it is important that we recognise it and therefore, the decade of ecosystem restoration which is the theme of this year’s environment day is very very important.
Earlier Zoonotic Outbreaks
Severe Acute Respiratory Syndrome (SARS)
Severe Acute Respiratory Syndrome or SARS is a type of coronavirus which is caused by the SARS-CoV virus (now known as Stars-CoV-1, as a predecessor of the current Covid-19 causing SARS-Cov-2).
According to the World Health Organisation (WHO), SARS-CoV, the virus that caused the SARS outbreak in 2003, had its ecological reservoir in bats, jumped from an animal reservoir (civet cats, a farmed wild animal) to humans and then spread between humans. The symptoms of SARS are similar to influenza symptoms and include fever, malaise, myalgia, headache, diarrhoea, and shivering.
As per the Centers for Disease Control and Prevention (CDC), the first case of atypical pneumonia was reported in the Guangdong province of southern China on November 16, 2002. It was first identified at the end of February 2003 and the outbreak lasted approximately six months as the disease spread to more than two dozen countries in North America, South America, Europe, and Asia before it was stopped in July 2003.
WHO declared SARS contained in July 2003, but a small number of SARS cases were reported until May 2004 in Singapore and Taipei. WHO claims that those cases were a result of laboratory accidents or possibly through animal-to-human transmission. There are no vaccines to prevent SARS at the given time while experimental vaccines are under development.
Middle East respiratory syndrome (MERS)
Middle East respiratory syndrome, commonly known as MERS, is a viral respiratory disease caused by coronavirus MERS‐CoV. MERS was first identified in Saudi Arabia in April 2012 and is a zoonotic virus, which means it is transmitted between animals and humans, and it is contractable through direct or indirect contact with infected animals.
The origins of the virus are not fully understood but according to the analysis of different virus genomes it is believed that it may have originated in bats and later transmitted to camels at some point in the distant past. Human-to-human transmission is possible, but only a few such transmissions have been found among family members living in the same household. In health care settings, however, human-to-human transmission appears to be more frequent, says WHO.
A typical symptom of MERS-CoV disease is fever, cough and shortness of breath. Pneumonia is a common finding, but not always present. Gastrointestinal symptoms, including diarrhoea, have also been reported, states WHO. At present there is no vaccine or specific treatment available to treat MERS, but as per WHO, several MERS-CoV specific vaccines and treatments are in development.
By the end of April 2021, a total of 2,574 laboratory-conﬁrmed cases of MERS including 886 associated deaths were reported globally.
H1N1 Virus Or Swine Flu
Swine flu was the first influenza pandemic of the 21st century that occurred in 2009-2010 and was caused by an influenza A(H1N1) virus. It’s called swine flu because in the past, the people who caught it had direct contact with pigs. That changed several years ago, when a new virus emerged that spread among people who hadn’t been near pigs. Symptoms of swine flu include fever, cough, sore throat, chills, weakness and body aches. Children, pregnant women and the elderly are at risk from severe infection. The flu however, reached a post-pandemic phase in 2010, when the WHO announced that the virus will continue as a seasonal influenza virus.
However, India saw a significant swine flu outbreak in 2015, with nearly 30,000 confirmed cases and almost 3,000 deaths by March, 2015, according to the Ministry of Health and Family Welfare data. Though in May, 2015, the government declared that the outbreak was over, India like the rest of the world, witnesses swine flu cases on a seasonal bases, especially in winter.
Nipah virus (NiV) is a zoonotic virus and can also be transmitted through contaminated food or directly between people. NiV was first recognised in 1999 during an outbreak among pig farmers in Malaysia. During the first recognised outbreak in Malaysia, which also affected Singapore, most human infections resulted from direct contact with sick pigs or their contaminated tissues.
Later in 2001, the virus was recognised in Bangladesh and ever since then nearly annual outbreaks have occurred in the country. The disease has also been identified periodically in eastern India. In Bangladesh and India, consumption of fruits or fruit products (such as raw date palm juice) contaminated with urine or saliva from infected fruit bats was the most likely source of infection. It also spread directly from human-to-human through close contact with people’s secretions and excretions.
In infected people, it causes a range of illnesses from asymptomatic (subclinical) infection to acute respiratory illness and fatal encephalitis. Infected people initially develop symptoms including fever, headaches, myalgia (muscle pain), vomiting and sore throat. This can be followed by dizziness, drowsiness, altered consciousness, and neurological signs that indicate acute encephalitis. Some people can also experience atypical pneumonia and severe respiratory problems, including acute respiratory distress. Encephalitis and seizures occur in severe cases, progressing to coma within 24 to 48 hours, says WHO.
There are currently no drugs or vaccines specific for Nipah virus infection.
Ebola Virus Disease
Ebola virus disease (EVD), formerly known as Ebola haemorrhagic fever, is a rare but severe, often fatal illness in humans. The virus is transmitted to people from wild animals (such as fruit bats, porcupines and non-human primates) and spreads in the human population through human-to-human transmission.
EVD first appeared in 1976 in two simultaneous outbreaks, one in what is now Nzara, South Sudan, and the other in Yambuku, Democratic Republic of the Congo. The latter occurred in a village near the Ebola River, from which the disease takes its name, explains WHO.
The symptoms – fever, fatigue, muscle pain, diarrhoea and others – are very much similar to other infectious diseases like Malaria and typhoid fever which makes the distinction difficult.
Within the genus Ebolavirus, six species have been identified and cases of some species are still reported in various countries like this year Guinea and the Democratic Republic of the Congo (DRC) reported cases of Zaire ebolavirus (Ebolavirus) infection. However, vaccines to protect against Ebola have been developed and have been used to help control the spread of Ebola outbreaks in Guinea and in the Democratic Republic of the Congo (DRC).
The Relationship Between Human Health And Environment
David Quammen is not surprised by the way zoonotic has hit human beings. There are untold numbers of viruses living in our rich and diverse ecosystem. Every species of animal has its own viruses, said Mr Quammen while talking to NDTV. Explaining how these viruses leap into a human body, Mr Quammen said,
When we go into that ecosystem to bring out fossil fuels or kill animals or bring wood and for other purposes, we cause disruption, expose ourselves and become vulnerable to the viruses. It is then the viruses spillover. Viruses are more dangerous than any other kind of pathogens in this day and age. Viruses can thrive and grow in cells. Viruses that are dangerous to humans generally come from animals like bats and rodents.
NDTV also spoke with Inger Andersen, UN Under-Secretary-General and Executive Director of the UNEP to understand the link between environmental health and human health. Ms Andersen warned that because of the biodiversity loss that is happening on a large scale, over 60 per cent of non-infectious disease and about 75 per cent of emerging infectious diseases are zoonotic. She said,
Now, we have to understand that to a large extent, human activity is largely to blame. We have intensified agriculture, we have fragmented nature, we have expanded infrastructure, we have extracted resources at the expense of these wild remote bases. Factory farms are linked to 25 per cent of infectious diseases in humans and travel and transport and food supply chains have erased what were borders and distances between some of these diseases and their appearance.
In a nutshell, disruption of biodiversity and exploitation of the ecosystem is exposing us to life-threatening viruses and according to the experts, if we don’t act now, we will face more pandemics in the future. Therefore, this World Environment Day will mark the launch of the ‘UN Decade Of Ecosystem Restoration’, highlighting the need to take steps to restore nature and planet earth.
This decade is designed to connect, empower and build political momentum; generate scientific research and create a groundswell of support for actions on ecosystem restoration. A decade might seem like a long time, but scientists say that the next 10 years would count most in the fight to avert climate change and biodiversity loss, says Ms Andersen.
NDTV – Dettol Banega Swasth India campaign is an extension of the five-year-old Banega Swachh India initiative helmed by Campaign Ambassador Amitabh Bachchan. It aims to spread awareness about critical health issues facing the country. In wake of the current COVID-19 pandemic, the need for WASH (Water, Sanitation and Hygiene) is reaffirmed as handwashing is one of the ways to prevent Coronavirus infection and other diseases. The campaign highlights the importance of nutrition and healthcare for women and children to prevent maternal and child mortality, fight malnutrition, stunting, wasting, anaemia and disease prevention through vaccines. Importance of programmes like Public Distribution System (PDS), Mid-day Meal Scheme, POSHAN Abhiyan and the role of Aganwadis and ASHA workers are also covered. Only a Swachh or clean India where toilets are used and open defecation free (ODF) status achieved as part of the Swachh Bharat Abhiyan launched by Prime Minister Narendra Modi in 2014, can eradicate diseases like diahorrea and become a Swasth or healthy India. The campaign will continue to cover issues like air pollution, waste management, plastic ban, manual scavenging and sanitation workers and menstrual hygiene.