The Key to Fighting Deadly Human Diseases? Animals.

The Key to Fighting Deadly Human Diseases? Animals.
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Researchers just uncovered new evidence that a parasite that infects more than 2 billion people worldwide can make some brain diseases and cancers even deadlier.

The culprit? An infection called Toxoplasma gondii. The parasite affects about one-third of the global population -- and often produces severe muscle pain, fevers and headaches in those suffering from it.  If a pregnant or soon-to-be-pregnant woman gets infected, her baby could experience developmental delays, hearing loss or seizures.

Humans can contract this disease from animals -- usually by eating undercooked meat from infected animals or accidentally ingesting waste from household cats.  The parasite can remain dormant but infective in soil and water for up to a year.

Too often, we pay attention to animal-borne diseases like Toxoplasma gondii only after they've taken hold in humans. Instead, public health officials must adopt a more holistic "One Health" approach to public health -- one that recognizes the interconnection among human, animal and environmental health.

Animals share approximately six out of every 10 infectious diseases that afflict humans, according to the Centers for Disease Control and Prevention. 

These diseases are wreaking havoc worldwide. Brazil just experienced its biggest outbreak of yellow fever in decades. The disease, which is caused by a viral infection in monkeys and spreads to humans via mosquitos, claimed over 250 lives since December.

This year in Sri Lanka, more than 100,000 people have contracted dengue fever -- a mosquito-borne disease that causes severe fever, intense joint and muscle pain and nausea. So far, 300 people have died.

In the United States, cases of West Nile Virus, which spreads to humans through mosquitos, are spiking in California. In Los Angeles County alone, 100 people were infected this year. The vast majority have experienced severe neurological problems and required a trip to the hospital.  Several have died.

Such infections are costly. The avian flu has already cost over $20 billion worldwide. A global bird flu pandemic could cause $2 trillion in economic damage. In the United States alone, treatment of rabies can reach over $500 million each year.

The One Health approach offers authorities a strategy for combatting diseases like these. By taking animal and environmental factors into account, health care professionals can better treat and prevent global pandemics. Hundreds of prominent doctors, veterinarians and researchers have endorsed One Health.

The strategy has proven remarkably effective. Take the case of rabies, which causes over 55,000 deaths in Asia and Africa annually. In Bangladesh, the World Health Organization employed a One Health approach that vaccinated both dogs and humans and employed prevention training programs. That cut rabies deaths in half within three years. 

Meanwhile, in Ghana, researchers conducted an extensive study of bats, which transmit viruses, to evaluate whether or not people in the surrounding communities were at risk of catching a disease.

My university, St. George's in Grenada, has integrated the One Health approach by giving the future doctors, veterinarians and public health professionals we educate across three schools the opportunity to take courses that emphasize the connections between human and veterinary medicine, public health and the environment.

Many animal-borne diseases are yet to be discovered. And those that are already apparent will continue to change in the coming years. Indeed, three-quarters of emerging or re-emerging infectious diseases in humans are shared by animals. 

Controlling these diseases will require a One Health approach. It's time for all health officials to embrace this strategy.

Calum Macpherson is Dean of the School of Graduate Studies at St. George's University. He is also founding director and vice-president of the Windward Islands Research and Education Foundation (WINDREF).

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