India is no stranger to infectious diseases. Conditions such as malaria, HIV, and tuberculosis (TB) have long plagued the country. However, there are a myriad of conditions which have either not yet hit the Indian shores or are otherwise geographically isolated. Any number of these conditions could reach epidemic proportions if left to spread unchecked.
India has shown recently aptitude in the containment of infectious disease outbreaks. With the recent announcement from Kerala that an outbreak of Nipah virus has been successfully contained, this marks the second time in two years that India has rapidly contained an outbreak within a month of its onset. Nonetheless, it is important that India is vigilant against emerging infectious conditions in the years ahead.
Scientists from the Indian Council of Medical Research (ICMR) and the National Centre for Disease Control (NCDC) have recently compiled a list of ten diseases with the potential to spark future epidemics in India. The entries on the list are as follows
Ebola is perhaps one of the most prominent concerns of the list. The disease is currently running rampant throughout the civil war-ravaged Democratic Republic of the Congo. Due to conflicts resulting from the war, treatment efforts have been impeded and the disease is beginning to breach the borders into neighbouring nations such as Uganda.
Dr Balram Bhargava, director general of the ICMR, said “nearly 30,000 Indians live in Uganda, where Ebola has been reported. Some of our troops are also present in the Democratic Republic of Congo, where the viral infection has led to an outbreak situation at present.”
Ebola is highly contagious, with a mortality rate of around seventy percent, making it a concerning prospect, particularly in densely populated urban areas. The disease is spread through bodily fluids. Much like India’s struggle with cholera, open defecation in rural areas could exacerbate the spread of the condition should it reach India.
Middle East respiratory syndrome (MERS) is a viral respiratory disease caused by a novel coronavirus (Middle East respiratory syndrome coronavirus, or MERS-CoV). The disease was only recently identified in 2012 in Saudi Arabia.
The family of viruses are also responsible for the common cold. Worth noting, however, is that around 35 percent of the patients identified as being infected with MERS-CoV have died.
The disease is not easily transmittable, with most cases reported as being passed in a hospital setting due to close confines of patients to carers and unsanitary practices. While not yet in India, the disease could present issues due to its method of transmission within hospitals, which is a commonly occurring situation currently with TB.
Avian influenza (H7N9)
This strain of the flu was first identified in China in March of 2013. This strain is likely one of the lower risk cases on the list in its current form due to the absence of human to human transmission.
Most known cases have occurred in instances where humans have sustained contact with birds, such as within poultry farms. In India, transmission may occur within workers in this industry, though a lack of sustained human-to-human transmission makes risks low.
However, as with all instances of influenza, the potential for mutation makes the disease a risk. As the symptoms are already severe in cases of this strain, any mutation that allows a greater level of transmission could result in a severe epidemic.
Avian influenza (H9N2)
In much the same way H7N9 presents a threat, H9N2 also presents issues through the potential for mutation. While symptoms for this strain are mild, the disease is already prevalent in areas of India where poultry farming is a major industry.
Studies have acknowledged that while there is a potential for the disease to become an epidemic, it is currently in a state where it poses little threat to humans, though is recognised as an “economically important” illness.
Yellow fever virus
The yellow fever virus (YFV) is a mosquito-borne flavivirus responsible for yellow fever (YF). The disease ranges in severity from influenza-like symptoms to far more severe issues such as liver and renal dysfunction, circulatory shock, and hemorrhage.
The disease is common in areas of tropical South America and Africa. It is currently not in circulation within India. The potential for outbreaks within India result from the fact that it is transmitted via the Aedes species of mosquitoes. This species is common to much of India and is responsible for the spreading of diseases such as malaria.
International travel presents the opportunity for an individual infected with yellow fever to travel to India, get bitten by a mosquito, and allow the virus to begin circulating within native breeding populations of mosquitoes. Should such an eventuality occur, the disease could flourish as other mosquito-borne infections have.
The Usutu virus is another flavivirus belonging to the Japanese encephalitis complex. The disease was first discovered in South Africa in 1959. The disease primarily affects birds, though a small number of human cases have been reported. In some cases these human infections were benign, though some resulted in severe encephalitis.
Currently the disease is known to occur across much of Africa, as well as in bird populations across parts of Europe. It has not yet been reported in India, though due to it being commonplace in many wild bird species could follow migration patterns to eventually spread outside of Africa and Europe.
Tilapia novel orthomyxo-like virus
This entry is a virus affecting the commercially farmed Tilapia fish species. There are no currently reported human cases of the disease, though its prevalence presents concern should the disease mutate to be able to affect humans.
The condition is known to exist across South America, Asia and Africa, with experts suggesting the disease may be far more prevalent than currently reported. As Tilapia is one of the most widely consumed fish the risk is more indirect to human health, with the potential to affect global food security due to mass mortality in the fish species.
Cyclovirus encapsulates a family of viruses most commonly found in dragonflies. These viruses have also been found in a number of commercially farmed animals. As a family of viruses there are sporadic outbreaks in areas across the globe, with examples such as in Chile and Malawi, in which the virus was also found in humans.
Cerebrospinal fluid of humans was tested in areas of these countries in individuals suffering from unexplained paraplegia. While not yet in India, the disease has shown the capacity to infect humans, with severe results such as paralysis. While dragonflies are a lesser epidemic threat as a vector than mosquitoes, the capacity of the disease to infect livestock elevates the risks that humans may become infected.
Banna Reo virus encephalitis
The Banna virus is perhaps one of the more likely diseases to present an epidemic within India in the near future due to both its proximity and method of transmission. Believed to originate within China, the disease has spread across southeast Asia, though is currently not documented within India.
The disease is spread by the Culex genus of mosquito and presents similar fever and encephalitis symptoms as Japanese encephalitis — another mosquito-borne disease within the same geographic region.
Due to the similar symptoms, transmission method and region affected, it is believed that outbreaks previously attributed to Japanese encephalitis may have been caused by the Banna virus. This opens up the possibility that the disease may already be in India, with cases of other similar diseases being misdiagnosed.
Canine parvovirus, as the name suggests, is a viral condition primarily affecting dogs. The disease can also spread to other mammalian species such as wolves, cats, or skunks, and is primarily spread through the bite of infected animals, or through fecal-oral contamination.
The disease has been shown to survive within soil samples for up to a year, meaning a dog may become infected in an area where all known disease cases have subsided. The mortality rate is high and there are no current treatments besides symptom management.
Though the disease is not currently transferable to humans, a mutation could allow this to occur. The spread of the disease would occur in much the same way as rabies, though with the addition of contaminated soil, allowing for far greater prevalence and epidemic potential. Given the sheer number of stray dogs in India, this could be a major issue.
Diversity of diseases: An epidemic nightmare
India is host to a huge range of diseases. Infectious diseases still run rampant amidst a surge in noncommunicable diseases. Neglected tropical diseases and a cumulatively large population suffering from rare diseases have created a situation where it is inevitable that certain diseases will be prioritised over those affecting only a small number.
If more diseases were to reach epidemic state, either through expected spread of the disease or mutation, an already stretched healthcare budget could reach its breaking point.