An 87-year-old Iranian man who has been living on the streets and hasn’t taken a bath in almost seven decades recently baffled scientists with his good health.

We first wrote about Amou Haji in 2014, dubbing him ‘the world’s dirtiest man‘. At the time, he was living in a small village in Southern Iran’s Fars province, surviving on roadkill and dirty water, and staying as far from bathwater as possible, thinking it would make him sick. He was 80-years-old at the time and appeared to be in good overall health, despite his questionable hygiene and living conditions. Well, apparently not much has changed since then, as a team of doctors recently conducted a series of tests that showed he was in surprisingly good health.

Photos and articles about Amou Haji have been doing the rounds on social media ever since his story originally went viral, over seven years ago. After all, his way of life is pretty incredible, in a time when many of us probably bathe more than we should. We once wrote about an Indian man who hadn’t bathed in 38 years, but at 67 years without a bath, Haji most likely holds the world record.

If anything, I was a bit surprised that it took a team of scientists so long to track down the octagenarian and run some tests on him to get some insight into the life of a person who shunned bathing so many decades ago, instead living in what can only be described as thoroughly unhygienic conditions. But, better late than never, I guess.

A team of doctors led by associate professor of parasitology, Dr Gholamreza Molavi, from the School of Public Health in Tehran visited Amou Haji in the village of Dejgah and convinced him to let him run some tests. They included tests for various forms of hepatitis and AIDS as well as parasites.

Dr. Molavi and his team were particularly interested in finding and studying the parasites and bacteria that might have developed in his unwashed body, but were surprised to find no disease-causing bacteria or parasites, except for Trichinosis, an infection that, in his case, appeared to be producing no symptoms.

The discovery was particularly shocking considering that the 87-year-old regularly consumes raw roadkill like porcupines and rabbits, drinks untreated water from puddles using unwashed rusty cans, and reportedly smokes dry animal feces if he doesn’t have tobacco for his pipe.

Dr Gholamreza Molavi believes that the only logical explanation for the test results is that Amou Haji has developed an enormously strong immune system over decades of living in extremely harsh conditions.

Despite his good health, 87-year-old Amou Haji routinely has to deal with the meanness of his fellow humans, many of whom taunt him and even physically abuse him, simply because of his lifestyle choices. The local governor recently appealed for people to leave him alone, saying that, despite his appearance, he was a gentle soul that never caused anyone any harm.