Tuberculosis (TB) is one of the top three infectious diseases along with HIV/AIDS and malaria. It infects nearly a third of the world’s population and still kills well over two million people a year, with India heading the list. Jawaharlal Nehru’s wife Kamala Nehru died of TB in her early thirties. It is the fastest spreading disease in our country.
Why is tuberculosis not eradicable? In large part, because we continue to drink milk and eat meat. Human tuberculosis is caused by a germ called Mycobacterium tuberculosis. A large percentage of cattle in India are infected with a strain of tuberculosis called Mycobacterium bovis. Are humans capable of getting tuberculosis from cattle infected by Mycobacterium bovis? Absolutely – through milk and beef. One interesting discovery, after unveiling the genomes of both bacterial villains, which share 99.95 per cent identical gene sequences, was that M. bovis came from M. tuberculosis, and not the other way around. Humans infected their cows 10,000–15,000 years ago and are being infected right back by them.
Humans can get TB from milk in various ways: through drinking milk produced in unsanitary conditions; through infected, tubercular workers who get it from lesions in the udders of cows wracked with bovine tuberculosis. A milk bucket is easily contaminated – a tubercular worker coughing into even one bucket could contaminate thousands of gallons when his milk is poured into a larger batch. Milk is a nutrient-rich liquid, so it is easy for microbes to grow in it. Even if there is a ‘modern’ milk processing plant with cows hooked up to machines and milk being transferred for boiling by and to machines, there are still areas where ‘foot traffic’ from employees brings in microbes.
Tuberculosis is passed from cows to humans even in the ultra-modernised dairies of the United States. A 15-month-old child died recently in New York of TB caused by M. bovis infection. A multi-agency investigation identified 35 more cases of M. bovis infection in New York City alone. TheUnited States requires testing of all dairy cows for bovine TB. Any
cow found infected is killed.
But in spite of regularly killing thousands of animals whole herds of 300,000 cows at a time are found infected every year.
In a country like Mexico which has better standards than India in keeping cattle, only 17 per cent of cattle have been found infected with TB.Go and look at the average Indian dairy. It is filthy, unsanitary and overcrowded. It has to be a breeding ground for TB. Neither the owner nor the useless animal husbandry inspector ever checks cows for any disease. One inspection which took place at the sperm-producing centre in Kerala found that all the bulls – whose sperm is injected into cows all over India – had TB. Not one bull was killed. No re-inspection took place, nor were any of the cows that had been injected with the bulls sperm inspected. Do even Amul and Mother Dairy inspect the village cows, from whom they take milk, for M. bovis infections? They don’t. Even if they did, would any villager agree to kill his/her milk producer? No.Most cows and buffaloes in India are kept in filthy dung-filled sheds, standing in their own feces for days. In cattle feces M. bovis will survive 1–8 weeks. Animals are probably more likely to be infected by M. bovis when they are poorly nourished or under stress.
In India, why is tuberculosis not eradicable? In large part, because we continue to drink milk and eat meat. Human tuberculosis is caused by a germ called Mycobacterium tuberculosis. A large percentage of cattle in India are infected with a strain of tuberculosis called Mycobacterium bovis. Are humans capable of getting tuberculosis from cattle infected by Mycobacterium bovis? Absolutely – through milk and beef.
Once the M. tuberculosis is ingested or inhaled, the disease may be ‘silent’ even to an experienced farmer or veterinarian, until the advanced stage. Infected people or animals that appear healthy are capable of transmitting the infection. Tuberculosis lesions can affect any part of the body but generally affect the lungs, lymph nodes and the chest cavity. The normally smooth internal lining of the chest cavity may be marred by lesions. How do you make out a milch animal has TB? A soft, chronic cough occurs once or twice at a time. In more advanced cases, there is a marked increase in the depth and rate of respiration as well as shortness of breath. In advanced stages, animals may show weakness, weight loss and fluctuating fever. The complicated nature of TB transmission, the resistance of the agent to disinfection, and the long period of infection prior to development of signs of disease have made bovine TB impossible to control.
M. bovis is spread in a number of ways by infected animals – through their breath, milk, discharging lesions, saliva, urine or droppings. Once in a herd, infection spreads from cow to cow by inhalation and from cows to calves via milk. People acquire TB by the same means as animals, i.e. by ingestion and inhalation.
Is there any evidence that human TB comes from cow and buffalo meat and milk? The government has made a Roadmap to Combat Zoonosis in India – a mission to combat diseases spread from humans to animals. Tuberculosis is number one on the list – even above rabies. This confirms that the government knows the danger in milk – but will not speak openly for fear of harming the industry.
All the studies done in India show vast numbers of cattle infected with TB. Even worse, the result of the study on ‘Bovine Tuberculosis in India: Potential Basis for Zoonosis’ carried out by All India Institute of Medical Sciences (AIIMS) shows that 15.7 per cent of humans had M. tuberculosis and 26.8 per cent of cattle had M. bovis. However, 8.7 per cent of humans had M. Bovis TB and 35.7 per cent cattle had ‘mixed infections’ as well. The study concluded that ‘the detection of mixed infection with the mycobacterial pathogenic duo in humans and bovines denotes the prospect of potential transmission of these pathogens from humans to cattle (zoonosis) and vice versa (reverse zoonosis). Animals infected with M. tuberculosis potentially constitute a grave public health hazard as virulent bacilli can be transmitted to humans.’
Similar studies have shown the same results. As recently as last year, seeing the increase in TB in Mumbaikars, doctors of the Preventive Social Medicine Department, of Ulhas Patil Medical College, Jalgaon, have asked the civic authorities to look at the cattle sheds as a source of human TB. The Head of the Department, Dr. Ashok Kale, was recently called by the Maharashtra Gazetted Veterinary Association to talk about the threat of zoonotic TB. ‘Animals are a source of TB virus. Milk, their excreta and breath of a TB-affected animal can spread the disease. And most of us are unaware of this,’ he said.
India is the largest consumer of milk in the world. And also is the country with the largest number of tuberculosis patients. Do you want your milk drinking child to be a TB statistic?