A new study has found that remote central Australian Aboriginal communities have the highest prevalence of human T-cell leukaemia virus type 1 (HTLV-1) in the world.
This devastating virus can cause severe disease, including aggressive adult T-cell lymphoma (ATL), HTLV-1-associated myelopathy, and uveitis, an inflammation of the eyes that can, if left untreated, lead to vision loss.
The study, published today in the PLOS Neglected Tropical Diseases, studied 720 people in seven remote Central Australian communities from 2014 to 2018. It found an overall rate of infection of 36.8% in adults, with rates of infection climbing with age to 49.3% for over-45s.
“In the first large scale community study of HTLV-1 prevalence in central Australia we found an adult prevalence of 36.8%, the highest reported worldwide,” the authors write in their paper, led by Lloyd Einsiedel from the Baker Heart and Diabetes Institute in Alice Springs, Northern Territory.
“Prevalence increased with age suggesting that sexual contact may be the predominant mode of transmission.”
The little-known HTLV-1 virus is found all over the world, with a high prevalence in Japan, the Caribbean, parts of South America and tropical Africa.
The virus acts by attacking the immune system, infecting T-cells. While plenty of infected people will never experience symptoms, the diseases the virus can cause can be devastating, and they are compounded by a lack of access to high-quality medical care.
One of the diseases is adult T-cell lymphoma. This is a particularly aggressive form of non-Hodgkin lymphoma, a cancer that can cause enlarged lymph nodes, confusion, bone pain and severe constipation. The disease is curable in some cases with treatment.
HTLV-1-associated myelopathy, on the other hand, is a slow, progressive disease of the spinal cord that acts in a similar way to multiple sclerosis (MS), reducing mobility and cognition over time.
Uveitis, another HTLV-1-associated disease, is prevalent in Aboriginal communities. If left untreated, it can cause blindness over a remarkably short period of time – on average around 21 months, according to a study in the British Journal of Ophthalmology. Addressing uveitis is deeply important, because blindness is a huge problem for many Indigenous Australians; it’s estimated that 90% of vision impairment or blindness experienced by Aboriginal and Torres Strait Islander people is preventable.
The HTLV-1 virus can also contribute to myriad other health problems, including a lung disease called bronchiectasis, and conditions that affect the skin and thyroid gland.
But despite appearing among such a high proportion of Aboriginal Australians, the authors of the new study say there is no public health strategy to control the transmission of HTLV-1 in Australia. In fact, their study is the first large-scale analysis of its prevalence among First Nations people, beginning the process of filling a worrisome and inexcusable gap in medical research.
“A better understanding of the patterns of occurrence of HTLV-1 at a community level is critical to guide the development of public health initiatives to reduce transmission,” the team writes.
They add that prevention is critically important because HTLV-1 infection is lifelong and cannot be treated. The results of their study, they conclude, supports the need “for the implementation of a coordinated program to inform Aboriginal Australians of the risks posed by HTLV-1 infection and to reduce the risk of viral transmission in this population”.
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