HTLV Type I/II in British Columbia Amerindians: A Seroprevalence Study and Sequence Characterization of an HTLV Type IIa Isolate

Abstract

It has been established that the human T cell lymphotropic viruses type I and II (HTLV-I and HTLV-II) are both present in some indigenous peoples of the Americas. While HTLV-I has been identified in coastal British Columbia Indians (BCIs), HTLV-II has not been previously reported in the BCIs or other Canadian Amerindians. The prevalence of HTLV-I and HTLV-II in these populations has not been extensively studied. In this article, we examine a group of BCIs from Vancouver Island who belong to the Nuu-Chah-Nulth and are known to have an increased incidence of rheumatic disease. In 494 serum samples from this tribe, the levels of prevalence of HTLV-I and HTLV-II were 2.8 and 1.6%, respectively. No association could be made between arthropathy and HTLV-I infection. In addition, we characterized an HTLV-II isolate of a BCI from the coastal mainland of British Columbia and with a history of intravenous drug abuse. This case represents the first molecular characterization of a Canadian Amerindian HTLV-II isolate: a subtype IIa virus with phylogenetic affinity for intravenous drug user isolates and containing an extended form of the Tax protein. These results are consistent either with this strain having been sampled from a polymorphic ancestral pool of HTLV-II that gave rise to the current epidemic spread of this virus by intravenous drug use and sexual transmission, or with its being "back-transmitted" into the BC Amerindian population in association with intravenous drug use.

Epidemiological Aspects and World Distribution of HTLV-1 Infection

“…Nevertheless, the HTLV-1 prevalence observed among 168,668 blood donors in the Toronto region was 0.02 and 2.3% among regional individuals and people of Caribbean origin respectively (Chiavetta et al, 1992). HTLV-1 infection was also described in Amerindians from the coastal regions of British Columbia (Dekaban et al, 1994; Picard et al, 1995; Peters et al, 2000). Furthermore, some associated diseases (ATL and TSP/HAM) were reported in coastal British Colombia Indians (Power et al, 1989; Oger et al, 1993; Dekaban et al, 1994; Gascoyne et al, 1996).…”

The epidemiology of human T‐cell lymphotropic virus types I and II in Canadian blood donors

“…Donors in the UK were most often UK born and of European ethnicity (Davison et al ., ). In Canada HTLV‐II infection has been reported in First Nations (Amerindian) populations in the Vancouver area (Peters et al ., ; Martin et al ., ). In our study, HTLV‐II was concentrated in western Canada, especially the city of Vancouver but the five donors who we were able to interview were all Canadian born and not of First Nations ethnicity.…”

“…HTLV‐II has a broad geographic range of distribution and is most often seen in indigenous peoples of the Americas, intravenous drug users and their sexual partners (Roucoux and Murphy, ). In Canada there have been reports in First Nations (indigenous) communities in the northern territory of Nunavut (HTLV‐I) (Sibbald, ) and in the province of British Columbia (HTLV‐I and ‐II) (Peters et al ., ; Martin et al ., ).…”

Risk acceptance of human T‐lymphotropic virus infection in solid organ transplantation—A survey of Atlantic Canadian ambulatory patients

“…Based on surveys of blood donors, the seroprevalence of HTLV in Canada is low and ranges between 0.007% and 0.012% . However, some data suggest that the prevalence is higher in some indigenous populations within Canada . The virus is most commonly transmitted through sexual intercourse, sharing injection tools, breast feeding, and blood transfusion .…”