Very high prevalence of infection with the human T cell leukaemia virus type 1c in remote Australian Aboriginal communities: Results of a large cross-sectional community survey

Infection with the human T cell leukaemia virus type 1 (HTLV-1) subtype C is endemic among Aboriginal people in central Australia. To provide insights into the risk factors for transmission, we conducted the first large-scale, community-based prevalence study in seven remote Aboriginal communities. Residents >2 years old were invited to participate in the study between August 2014 and June 2018. HTLV-1 infection was defined as a positive western blot (WB) test or a positive HTLV-1 PCR. 720 community residents participated in the study (children <15 years, 142; adults, 578). Prevalences for children and adults were 3.5% (5/142) and 36.8% (213/578), respectively, reaching 49.3% (106/215) for those older than 45 years. A wide range of proviral loads were measured for both asymptomatic and symptomatic participants with no difference within groups according to age or gender; however, median PVL was 1.34 log10 higher for symptomatic participants. The adult prevalence of HTLV-1 infection in central Australia is the highest reported worldwide. Sexual contact is likely to be the predominant mode of transmission.

HTLV-I and Strongyloides in Australia: The worm lurking beneath

Strongyloidiasis and HTLV-I (human T-lymphotropic virus-1) are important infections that are endemic in many countries around the world with an estimated 370 million infected with Strongyloides stercoralis alone, and 5-10 million with HTVL-I. Co-infections with these pathogens are associated with significant morbidity and can be fatal. HTLV-I infects T-cells thus causing dysregulation of the immune system which has been linked to dissemination and hyperinfection of S. stercoralis leading to bacterial sepsis which can result in death. Both of these pathogens are endemic in Australia primarily in remote communities in Queensland, the Northern Territory, and Western Australia. Other cases in Australia have occurred in immigrants and refugees, returned travellers, and Australian Defence Force personnel. HTLV-I infection is lifelong with no known cure. Strongyloidiasis is a long-term chronic disease that can remain latent for decades, as shown by infections diagnosed in prisoners of war from World War II and the Vietnam War testing positive decades after they returned from these conflicts. This review aims to shed light on concomitant infections of HTLV-I with S. stercoralis primarily in Australia but in the global context as well.

Infective dermatitis: A purely cutaneous manifestation of HTLV-1 infection

Infectious dermatitis is a cutaneous manifestation of HTLV-1 infection. Although initially described in children in Jamaica, it is well documented that the disease can also present in adults. The clinical picture is of an oozing dermatitis affecting the scalp, face, retroauricular areas, the neck, and intertrigious areas, such as the axilla and groin. Histologically it has two patterns: a superficial perivascular dermatitis or a lichenoid dermatitis. The epidermal hyperplasia may mimic psoriasis. An important differential diagnosis is with mycosis fungoides, with epidermotropism, alignment of lymphocytes along the epidermal junction, lymphocytes in halo and wiry bundles of collagen in the papillary dermis. An important difference is the lack of marked lymphocytic atypia. The infiltrate is composed of a predominance of CD8-positive lymphocytes, analogous to what is seen in tropical spastic paraparesis. Infectious dermatitis patients may be confused with many common dermatological conditions, such a atopic dermatitis and contact dermatitis. Its diagnosis represent a challenge both to clinicians and dermatopathologists working in endemic areas.