Anthrax spread in Odisha linked to animal carcasses, says probe

Anthrax is an infectious and often fatal disease caused by bacillus anthracis. It occurs naturally in soil and affects domestic and wild animals.

The spread of anthrax cases in Odisha is due to handling of animal carcasses, with no evidence of human-to-human transmission, a central investigation into the recent outbreak that infected 12 persons, killing one of them, has found.

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“The regional director of directorate generate of health services has inquired and sent a report,” a central government official said, requesting anonymity.

Anthrax is an infectious and often fatal disease caused by bacillus anthracis. It occurs naturally in soil and affects domestic and wild animals. It is a zoonotic disease, infecting people if they come in contact with infected animals or contaminated animal products.

“All of those who have been infected, including the one who died, handled the carcasses of (infected) animals as per the investigation report,” the official said, adding that the situation in the eastern state was under control.

Anthrax typically does not spread from animal to animal or person to person. The bacteria produces spores on contact with oxygen. If ingested or inhaled by an animal, or after entering through cuts in the skin, they can germinate and cause the disease. Inhalation anthrax is the most serious form and can kill quickly if not treated immediately. It is considered by experts a potential bioterrorism organism.

In humans, anthrax manifests in three distinct patterns -- cutaneous, gastrointestinal and inhalational, according to the World Organisation for Animal Health. The most common is a skin infection, where people become infected handling animals or animal products that contain spores. The disease can cause severe illness in both humans and animals.

Odisha is a major contributor in the number of anthrax cases, according to studies done in India.

“Anthrax is a major but neglected zoonotic disease of public health concern in India with Odisha contributing a major share to the disease burden. The real burden of anthrax in India is not understood precisely since a significant number of cases go unreported and only a portion of human cases seek medical care,” said researchers in a study published in 2021 entitled ‘One Health approach for elimination of human anthrax in a tribal district of Odisha: Study protocol’.

Over the past 15 years, 14 out of 30 districts in Odisha have experienced outbreaks of human anthrax, with 1,208 cases and 436 deaths, the study found.

“Among those affected districts, Koraput has more than 300 human anthrax cases including 10 deaths over the past six years. Almost all the cases came from a group of indigenous tribes involved in handling and consuming animal carcasses,” the study said.

Anthrax is one of the top 10 diseases reported in India and one of the major causes of deaths in livestock, with a high fatality rate, National Animal Diseases Referral Expert System data show. High density of tribal population of over 22% and extensive forest cover makes Odisha prone to anthrax outbreaks as meat is one of the primary foods of most indigenous tribes.

Without treatment, the disease has high fatality of one in five to one in four, according to Vinod Scaria, scientist at CSIR Institute of Genomics and Integrative Biology.

The Indian Council of Medical Research is working to ensure effective diagnosis and disease management, and has formed detailed guidelines for affected districts. ICMR’s Regional Medical Research Centre in Bhubaneswar has conducted a study in four districts of Odisha -- Koraput, Rayagada, Malkangiri and Sundargarh -- on control strategies.

“People living in tribal areas are largely affected. Therefore, it is crucial to devise and implement control strategies keeping this fact in mind,” a government researcher said, declining to be named.