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Some people asked me this Q recently. My answer is an emphatic  'NO'!

According to some, as  Indians are exposed to more dirt and germs, they become more immune to diseases! 

Are Indians getting the highest exposure to dirt than people from any other country? Where is the evidence? No, this is not a correct assumption!

Well as a person of science if I say something I should also provide evidence. So, here it is:

But first let me make this clear:  Communicable diseases are infectious diseases. An infectious disease is contagious when it spreads through direct, bodily contact with an infected person, their discharges, or an object or surface they’ve contaminated.

Communicable diseases are infectious diseases. An infectious disease is contagious when it spreads through direct, bodily contact with an infected person, their discharges, or an object or surface they've contaminated(3).

There is no evidence to suggest that “Indians in general" have a stronger immune system to fight either Covid-19 or  other diseases. The human immune system is very complex, and interacts differently with a range of variables based on the environment and various other factors, including smoking, use of immunosuppressant drugs, sleep, stress, the food we eat, and exercise. Therefore, suggesting that Indians have “stronger immune systems" is a highly generic and misleading statement. How do we then explain that we have the largest share of the global burden (27%) of tuberculosis-poor T Cell function (1)?  
The three main killers of Tuberculosis, HIV and Malaria have plagued India, Africa and several countries in the Southern hemisphere much more than the European and North American nations. Indians 're more vulnerable to these diseases. This is a fact.
And, on the other side we also have the second highest prevalence of asthma (overactive immune system) in the world, and the highest number of asthma deaths (Global Burden of Disease data) in the world.  

Then ...


CLAIM: ‘More immunity in Indian genes’ – The title of Nature Asia magazine article.“Our bodies have one of the toughest immune systems in the world. We have grown up surrounded by so much filth and pollution that our natural resilience is much stronger than people in the developed world.” – Sandipan Deb in Livemint.
VERDICT: False.FACT-CHECK

1. The Livemint article is based on a superficial understanding of the title of the Nature Asia, not its text.The Nature Asia article is titled ‘More immunity genes in Indians’. However, the article itself does not make any such claims that, on the basis of the research study quoted, that Indians will be protected from the coronavirus pandemic or other infections due to their biologically inherited ‘resilience’. It simply states that Indians may have more genes linked with immunity as per the data. Also, one of the authors of the article and the research study Rajalingam Raja wrote, “Whether having more activating KIR genes is an advantage or disadvantage for Indians remains to be elucidated.” This means that the genes tested through this study are not a piece of conclusive evidence that the contested tougher immunity will be an advantage for Indians in any way.

2. The Nature Asia article is based on a research study based on a single gene polymorphism in various ethnicities. The Nature Asia article is based on a research study which relies upon a single gene KIR2DL5 polymorphism in many ethnicities including Indian, East Asian, white (Caucasian) and black (African Americans), suggesting that the gene is not unique to Indians only. Also, no evidence suggests that the presence of gene translates to gene expression or phenotypic change (e.g. higher immunity) in this case.Nature Asia article based its claim on a gene polymorphism study by Du and colleagues (7). Genetic polymorphism is the occurrence of multiple forms of a single gene which is expressed in the same population as a trait or a phenotype (6). It is similar, but not the same, as varying levels of pigmentation in eyes, hair or skin colour. The study quoted showed the nature of polymorphism of one gene KIR2DL5 in four ethnic groups: Caucasians (European race, mostly white), Asian-Indians (South Asians), African-Americans and Asians (East Asians, i.e. Korean, Vietnamese, Japanese and Filipino).KIR2DL5 (or CD158f) is the last identified KIR gene (the inhibitory receptor expressed on the surface of immune cells), with KIR2DL4, it makes up a structurally divergent lineage conserved in different primate species such as humans. The percentage frequency of this KIR2DL5 gene in Indians is used as an indicator of higher immunity.The graph from the research study illustrates that the percentage frequency of KIR2DL5 (A and B, polymorphic forms of KIR2DL5 gene) is higher in Asian Indians than the other ethnic populations studied. However, another graph from the same study suggests that the Individuals carrying the KIR2DL5 gene vary substantially among populations ranging in frequency from 35-85%. Thus, as per the author’s conclusions, higher immunity can be found in every ethnicity ranging from 35-85% population, not just in Indians (2).

And my article on this topic: Countering the misinformation on immune development says with evidence  playing in nature (good exposure to microbes), not dirt (bad exposure to disease causing microbes) is the key point one should understand .

https://kkartlab.in/group/some-science/forum/topics/countering-the-...

(Please click on the above link and read the article before proceeding further)


Some mis information is going on on the net and in the media about Indians' immunity to diseases. We know this.   But let us check the facts.

India’s top infectious disease killed over 4,40,000 people in 2018 (4)

To put the figures of coronavirus in perspective, tuberculosis alone kills an average of 4 lakh Indians annually, and the daily average of over 1,200 is way beyond the COVID-19 fatalities in the country.

The country’s tally of officially confirmed cases to 71,75,880 till 13th Oct, 2020. The death toll is 1,09,856. According to the health ministry, 8,38,729 cases are still active, while 62,27,295 people have been cured or discharged or have migrated. 

But the  media says ( and the research work done by CCMB confirms this ) the figures will be much, much higher than these official figures.

Similarly, the far more common and recurrent H1N1 seasonal flu kills more than a thousand people on average in the country. 
 According to the WHO, there have been three to five million cases of severe illness due to influenza, and about 290,000 to 650,000 respiratory deaths. Already 1,469 people in India have been affected by the communicable respiratory disease caused by a sub-type of influenza A virus, called H1N1, and 28 people have died, according to the National Centre for Disease Control data ( released this year in March) .
Since the 2009 H1N1 pandemic, India has seen a steady number of H1N1 cases — in 2015, 42,592 cases and 2,991 deaths were reported; in 2017, 38,811 cases and 2,270 deaths were recorded. 
 Vector-borne diseases like malaria, dengue, acute encephalitis syndrome (AES) and Japanese encephalitis also continue to pose a challenge to the health system. While India continues to report lakhs of malaria and dengue cases each year, they have resulted in 1,055 and 1,094 deaths respectively over five years to 2019.

According to World Health Organization (WHO), there were an estimated 219 million malaria cases and 4,35,000 related deaths in 2017. India accounts for 4 per cent of the global malaria burden even as the government has set a target to eradicate the disease by 2030.

AES and Japanese encephalitis too have a high mortality rate of 9.07 per cent, triple of the coronavirus rate, if cases are considered from 2015 to 2019. In 2019, 16,758 cases were reported, including 963 deaths. 

Despite being one of the world’s largest economies, India has some serious issues with poverty and some of the most severe issues with infectious diseases on the planet.

The World Health Organization (WHO) also says soil-transmitted helminth (STH) infections are among the most common infections worldwide and affect the poorest and most deprived communities. They are transmitted by eggs present in human feces which in turn contaminate soil in areas where sanitation is poor.

In India, the number of cases of the top three STH, Ascaris lumbricoides, Trichuris trichiura and the hookworms totals more than 280 million cases.

Morbidity is related to the number of worms harbored. People with light infections usually have no symptoms. Heavier infections can cause a range of symptoms including intestinal manifestations (diarrhea and abdominal pain), general malaise and weakness, and impaired cognitive and physical development. Hookworms cause chronic intestinal blood loss that can result in anemia.

Visceral leishmaniasis

Visceral leishmaniasis, also known as kala-azar, is caused by the vector borne parasite, Leishmania donovani and can cause very serious systemic disease. Doctors without Borders (MSF) says Kala-azar is the second largest parasitic killer in the world, only behind malaria.

It is estimated that of the between 200,000 and 400,000 new cases a year, India accounts for approximately 60 percent of cases, with a bulk of the cases in the East India state of Bihar.

Dengue fever

Dengue fever is an infectious disease carried by mosquitoes and caused by any of four related dengue viruses. This disease used to be called “break-bone fever” because it sometimes causes severe joint and muscle pain that feels like bones are breaking.

There are three types of dengue fever in order of less severe to most: the typical uncomplicated dengue fever, dengue hemorrhagic fever (DHS) and dengue shock syndrome (DSS).

A study in the American Journal of Tropical Medicine and Hygiene by Brandeis University researchers suggests India sees some 6 million dengue fever cases annually while other estimates dwarf that number at more than 30 million per year. Either way, it’s much higher than what the Ministry of Health reports each year.

Malaria

Some estimates say India accounts for 35 percent of the world’s malaria burden. Another paper estimates the malaria burden in India at India at 180 million, with as many as 90 million cases of P. falciparum malaria per year.

A study conducted by teams from the office of the Registrar General of India, Centre for Global Health Research at St Michael’s Hospital and University of Toronto, Canada, published in The Lancet on 20 November 2010 has reported that malaria causes 205,000 malaria deaths per year in India before age 70 years

No matter what numbers you use, malaria is a huge burden in India.

Elephantiasis of leg due to filariasis/CDC
Elephantiasis of leg due to filariasis/CDC

Lymphatic Filariasis

The Global Network for Neglected Tropical Diseases says lymphatic filariasis (LF), also known as elephantiasis, infects an estimated 67 million people in 80 countries worldwide, and is an extremely painful, debilitating and disfiguring disease. Found mainly in tropical and sub-tropical climates, the disease is caused by the thread-like parasitic filarial worms Wuchereria bancrofti and Brugia malayi, which live in the lymphatic system and can cause extreme swelling of the extremities and genitals. More than 40 million sufferers of elephantiasis are seriously incapacitated and disfigured from the disease.

India reports about 6 million LF cases and the South Asia region 60 million.

Trachoma

India reports about one million cases of the blinding bacterial infection, trachoma. Trachoma is an infectious disease of the eye caused by the bacterium Chlamydia trachomatis, and is the world’s leading cause of preventable blindness. Approximately 41 million people in 57 countries worldwide have active trachoma, and an estimated eight million have lost their sight due to complications from the disease.

Leprosy

According to official reports received from 103 countries and territories, the global registered prevalence of leprosy at the end of the first quarter of 2014 stood at 180,464 cases. India has more than 87,000 registered cases, or more than four out of 10 cases globally.

WHO says leprosy is caused by a slow-growing bacillus, Mycobacterium leprae. It is transmitted via droplets from the nose and mouth of untreated patients with severe disease, but is not highly infectious. If left untreated, the disease can cause nerve damage, leading to muscle weakness and atrophy, and permanent disabilities.

Leprosy can be easily treated with a 6–12-month course of multidrug therapy. The treatment is highly effective, and has few side-effects and low relapse rates; there is no known drug resistance.

Rabies

According to the Global Alliance for Rabies Control, rabies is currently responsible for an estimated 59,000 human deaths a year, almost all transmitted via dog bites. Up to 60% of all rabies deaths are children under the age of 15.

Of the global total of human rabies deaths, India accounts for one-third, or 20,000 deaths.

Clearly, this list is not all-inclusive of the infectious disease issues in India, but you get the picture, there are many infectious disease problems in the world’s second most populous country (5).

Numbers don't lie!

SO?! Do you still think Indians are immune to the diseases?

NO! And that is a big NO. We still have to go a long way to achieve this dream.

 
Footnotes:

1: https://www.livemint.com/opinion/online-views/no-there-is-no-eviden...

2. https://www.altnews.in/indians-do-not-have-genetic-protection-again...

3. https://www.dictionary.com/e/contagious-vs-infectious-the-differenc...'ve%20contaminated.

4. https://indianexpress.com/article/india/coronavirus-india-top-infec...

5.  http://outbreaknewstoday.com/india-top-infectious-disease-concerns-...

6. https://www.ncbi.nlm.nih.gov/books/NBK6475/

7. https://www.nature.com/articles/gene200839#author-information

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