Many Die From Snakebites Despite the Availability of Antivenom

By Rob Goodier

November 30, 2020

NEW YORK (Reuters Health) - Snakebites may have claimed nearly 65,000 lives globally last year and are accountable for 3 million years of life lost, placing them at the top of the list of neglected tropical diseases, a new modeling study suggests.

More than 80% of the mortality occurred in India, in spite of the availability of polyvalent antivenom, according to findings presented November 19 at the virtual annual meeting of the American Society of Tropical Medicine and Hygiene.

"We show that antivenom existence alone is not sufficient to prevent death and disability from venomous snakebites. There needs to be investments in the health system and distribution of antivenom to rural and poor areas where venomous snakebites are the biggest problem and victims do not access a hospital or clinic in time to prevent complications," lead author Nicholas Roberts, a medical student at Weill Cornell Medical College in New York City, told Reuters Health by email.

Roberts and his research team extrapolated their findings in part from data in Global Burden of Disease 2019, a report produced by the Seattle- based Institute for Health Metrics and Evaluation where Roberts served as a fellow.

To obtain their estimates, the researchers ran a mortality model using global data, then zeroed in on India, the site of the greatest disease burden. Extracting data from a review of literature on India yielded case fatality rates, clinical manifestations of snakebites, and the distribution of venomous snakes in the country.

The model estimated that 64,847 people died from snakebite in 2019 (95% uncertainty interval, 39,606 to 80,325); 52,345 (95% UI, 30,106 to 65,735) of these deaths occurred in India.

The researchers also found that 3 million disability-adjusted life-years were lost globally from snakebites, a figure that reflects the long-term morbidity, Roberts said.

The researchers also developed a forecast suggesting that the World Health Organization will likely miss its goal to halve the disease burden of snakebites by the year 2030.

"Due to increasing population, there will actually be a greater absolute number of snakebite deaths in 2030 compared to now," Roberts said.

India's snakebite problem stems from its status as home to the "big four" venomous snakes: the spectacled cobra (Naja naja), common krait (Bungarus caeruleus), Russell's viper (Daboia russelii), and the saw-scaled viper (Echis carinatus).

In 2017, the World Health Organization labeled snakebites as a Neglected Tropical Disease, a list of diseases that afflict more than 1 billion people globally, yet are overlooked and underfunded for research.

The modeling effort also spotlighted the absence of data in areas plagued by snakebites, particularly in sub-Saharan Africa, where there was not enough information available to make accurate estimates, Roberts said.

Other experts agree.

"Snakebite being listed as Category A Neglected Tropical Disease by WHO in 2017 was an important first step, but we need more resolution of the problem on local and regional levels to guide control and treatment measures. These modeling data are a step in that direction," said Dr. Daniel Bausch, a professor at the London School of Hygiene and Tropical Medicine, who was not involved in the research.

"As the authors state, a better understanding of the epidemiology can help healthcare providers prepare with antivenom, dialysis machines, and ventilators, etc.," Dr. Bausch told Reuters Health by email.

SOURCE: American Society of Tropical Medicine and Hygiene 2020 annual meeting, November 19, 2020.