Human T-cell lymphotropic virus type I infection and disease in the Pacific basin.

Human T-cell lymphotropic virus type I (HTLV-I), the cause of adult T-cell leukemia/lymphoma (ATLL) and HTLV-I-associated myelopathy/tropical spastic paraparesis (HAM/TSP), is widespread in the Pacific basin. Modes of virus transmission include blood transfusion (and intravenous drug use), breast milk, and sexual intercourse. High prevalences of HTLV-I infection and disease occur among the inhabitants of southwestern Japan and among first- and second-generation (issei and nisei) Japanese-Americans in the Hawaiian Islands. Other Pacific populations with high prevalences of HTLV-I infection include several remote groups in West New Guinea, Papua New Guinea, the Solomon Islands, and Vanuatu, which have had no contact with Japanese or Africans. By contrast, Micronesian and Polynesian populations, even those with prolonged contact with Japanese, exhibit low prevalences or no evidence of HTLV-I infection. Low prevalences of infection are also found in Australia, except among some aboriginal populations. Changing patterns of HTLV-I infection and disease are no better exemplified than in Japan, where striking reductions in transfusion-acquired infection and subsequent development of HAM/TSP have followed the institution of nationwide screening of blood donors for HTLV-I infection. Furthermore, virus transmission from mother to infant by means of infected breast milk has been markedly curtailed in HTLV-I-hyperendemic regions in Japan by interrupting the practice of breast feeding by HTLV-I-infected mothers. The next frontier of HTLV-I research is in Melanesia, where highly divergent sequence variants of HTLV-I have been discovered.     

Complete nucleotide sequence of a highly divergent human T-cell leukemia (lymphotropic) virus type I (HTLV-I) variant from melanesia: genetic and phylogenetic relationship to HTLV-I strains from other geographical regions.

The high prevalences of antibodies against human T-cell leukemia (lymphotropic) virus type I (HTLV-I) reported for remote populations in Papua New Guinea and the Solomon Islands and for some aboriginal populations in Australia have been verified by virus isolation. Limited genetic analysis of the transmembrane portion (gp21) of the envelope gene of these viruses indicates the existence of highly divergent HTLV-I strains in Melanesia. Here, we report the complete nucleotide sequence of an HTLV-I isolate (designated HTLV-IMEL5) from the Solomon Islands. The overall nucleotide divergence of HTLV-IMEL5 from the prototype HTLV-IATK was approximately 8.5%. The degree of variability in the amino acid sequences of structural genes ranged between 3 and 11% and was higher (8.5 to 25%) for the regulatory (tax and rex) genes and the other genes encoded by the pX region. Since HTLV-IMEL5 was as distantly related to HTLV-II as to the other known HTLV-I strains, it could not have arisen from a reocmbinational event involving HTLV-II but rather might be an example of independent viral evolution in this remote population. These data provide important insights and raise new questions about the origin and global dissemination of HTLV-I.     

How to make fire: Resonant rupture within Melanesian charismatic revivalism

Recent theoretical developments within the anthropology of Christianity have shifted away from conceptualising the uptake of Pentecostal‐charismatic Christianity in polarised terms of rupture versus continuity towards more inclusive, dynamic interpretations that appreciate both underlying cultural synergies alongside deeply felt projects of personal and collective moral and spiritual transformation. Drawing upon Marshall's concept of ‘resonant rupture’, I explore how a series of interconnected revivals that occurred in many places throughout Solomon Islands and Papua New Guinea resonated with pre‐existing elements of indigenous religion and cosmology. At the same time, however, I show that, although a broad conjuncture between tradition and Pentecostal‐charismatic Christianity existed, the events that constituted these movements were understood by revival participants as unequivocally Christian, innovative and radically new, thus revealing the simultaneous processes of resonance and rupture at work. In support of my argument I focus upon reports of religious intensification during this formative period from three different ethnographic settings, namely, Malaita, Solomon Islands, Enga Province, Papua New Guinea and the Min culture area, Papua New Guinea, respectively. All of the examples vividly exemplify Melanesian Christians absorbing existing religiosity into their new worship while at the same time imposing a radical change on the level of asserted meaning.     

Multilocus population genetic analysis of the Southwest Pacific malaria vector Anopheles punctulatus

The population structure and history of the cryptic malaria vector species, Anopheles punctulatus (Doenitz), was investigated throughout Papua New Guinea and the Solomon Islands with the aim of detailing genetic subdivisions and the potential for movement through this biogeographically complex region. We obtained larval collections from over 80 sites and utilised a diverse array of molecular markers that evolve through different processes. Individuals were initially identified to species and genotyped using the ribosomal DNA second internal transcribed spacer. DNA sequencing of a single copy nuclear ribosomal protein S9 and the mitochondrial cytochrome oxidase I loci were then investigated and 12 nuclear microsatellite markers were developed and analysed. Our data revealed three genetically distinct populations – one in Papua New Guinea, the second on Buka Island (Bougainville Province, Papua New Guinea), and the third on Guadalcanal Island (Solomon Islands). Genetic differentiation within Papua New Guinea was much lower than that found in studies of other closely related species in the region. The data does suggest that A. punctulatus has undergone a population bottleneck followed by a recent population and range expansion in Papua New Guinea. Humans and regional economic growth may be facilitating this population expansion, as A. punctulatus is able to rapidly occupy human modified landscapes and traverse unsealed roads. We therefore anticipate extensive movement of this species through New Guinea – particularly into the highlands, with a potential increase in malaria frequency in a warming climate – as well as relatively unrestricted gene flow of advantageous alleles that may confound vector control efforts.     

Independent histories of human Y chromosomes from Melanesia and Australia

To investigate the origins and relationships of Australian and Melanesian populations, 611 males from 18 populations from Australia, Melanesia, and eastern/southeastern Asia were typed for eight single-nucleotide polymorphism (SNP) loci and seven short tandem-repeat loci on the Y chromosome. A unique haplotype, DYS390.1del/RPS4Y711T, was found at a frequency of 53%-69% in Australian populations, whereas the major haplotypes found in Melanesian populations (M4G/M5T/M9G and DYS390.3del/RPS4Y711T) are absent from the Australian populations. The Y-chromosome data thus indicate independent histories for Australians and Melanesians, a finding that is in agreement with evidence from mtDNA but that contradicts some analyses of autosomal loci, which show a close relationship between Australian and Melanesian (specifically, highland Papua New Guinean) populations. Since the Australian and New Guinean landmasses were connected when first colonized by humans > or =50,000 years ago but separated some 8,000 years ago, a possible way to reconcile all the genetic data is to infer that the Y-chromosome and mtDNA results reflect the past 8,000 years of independent history for Australia and New Guinea, whereas the autosomal loci reflect the long preceding period of common origin and shared history. Two Y-chromosome haplotypes (M119C/M9G and M122C/M9G) that originated in eastern/southeastern Asia are present in coastal and island Melanesia but are rare or absent in both Australia and highland Papua New Guinea. This distribution, along with demographic analyses indicating that population expansions for both haplotypes began approximately 4,000-6,000 years ago, suggests that these haplotypes were brought to Melanesia by the Austronesian expansion. Most of the populations in this study were previously typed for mtDNA SNPs; population differentiation is greater for the Y chromosome than for mtDNA and is significantly correlated with geographic distance, a finding in agreement with results of similar analyses of European populations.     

Detection of HTLV-I in peripheral blood lymphocytes from patients with chronic HTLV-I-associated myelopathy/tropical spastic paraparesis and asymptomatic carriers by PCR-in situ hybridization

Less than 5% of people infected with human T-lymphotropic virus type I (HTLV-I) develop HTLV-I-associated myelopathy/tropical spastic paraparesis (HAM/TSP), a chronic progressive neurologic disease. A number of factors have been implicated in the development of HAM/TSP including heterogeneity of viral sequences, host-genetic background, viral-specific cellular immune responses and viral load. This study examined the presence of HTLV-Itax DNA in peripheral blood lymphocytes (PBL) from 2 chronic HAM/TSP patients and 2 asymptomatic HTLV-I carriers by using PCR-in situ hybridization (PCR-ISH) for the in situ presence of proviral HTLV-Itax DNA. By this technique, rare PBL from these HTLV-I-infected individuals contained HTLV-I DNA. PCR-ISH did not detect any difference in the number of infected cells between HAM/TSP patients and asymptomatic carriers.     

Blood group, red cell enzyme and serum protein types in the Buka Islanders, Papua New Guinea

Genetic marker studies on a sample of 80 speakers of the Petats and Tinputs families of languages, all pupils at a single high school, indicate a homogeneity among them which can be extrapolated to their areas of origin. Buka and its offshore islands and the northern part of Bougainville Island in the North Solomons Province of Papua New Guinea. Several markers systems, most notably first-locus phosphoglucomutase and liver acetyltransferase, reinforce the morphological evidence that these peoples are quite distinct from most other Papua New Guinea populations, with whom, however, there has been some gene exchange, probably through East New Britain. Their principal affinities are with the peoples of the Solomon Islands to the south.     

Multistability in a Model for CTL Response to HTLV-I Infection and Its Implications to HAM/TSP Development and Prevention

Human T-cell leukaemia/lymphoma virus type I (HTLV-I) is a retrovirus that has been identified as the causative agent of HTLV-I-associated myelopathy/tropical spastic paraparesis (HAM/TSP) and other illnesses. HTLV-I infects primarily CD4⁺ T cells and the transmission occurs through direct cell-to-cell contact. HAM/TSP patients harbor higher proviral loads in peripheral blood lymphocytes than asymptomatic carriers. Also, HAM/TSP patients exhibit a remarkably high number of circulating HTLV-I-specific CD8⁺ cytotoxic T lymphocytes (CTLs) in the peripheral blood. While CTLs have a protective role by killing the infected cells and lowering the proviral load, a high level of CTLs and their cytotoxicity are believed to be a main cause of the development of HAM/TSP. A mathematical model for HTLV-I infection of CD4⁺ T cells that incorporates the CD8⁺ cytotoxic T-cell (CTL) response is investigated. Our mathematical analysis reveals that the system can stabilize at a carrier steady-state with persistent viral infection but no CTL response, or at a HAM/TSP steady-state at which both the viral infection and CTL response are persistent. We also establish two threshold parameters R ₀ and R ₁, the basic reproduction numbers for viral persistence and for CTL response, respectively. We show that the parameter R ₁ can be used to distinguish asymptomatic carriers from HAM/TSP patients, and as an important control parameter for preventing the development of HAM/TSP.     

Knowing and the truth: Three histories of Daugo Island,Papua New Guinea

Courts of law in Melanesian countries, particularly in the aftermath of the colonial period, have attempted to accommodate ‘custom’. In Papua New Guinea they commonly hear land claims under terms of reference that acknowledge the wide variety of customs among the many ethno‐linguistic groups comprising the nation. A corollary of this liberalism is that, in theory, they admit ‘traditional evidence’ including legends and myths. Yet as courts of law they are required to apply some criteria of proof and to search for the ‘truth’ by examining the ‘facts’. A long‐running land case from Papua New Guinea and its aftermath raises interesting questions about what happens when oral history encounters these legal imperatives, and may help us appreciate why Melanesians often do not regard a court's decision as final.     

An extended survey of the genetic polymorphism at the human coagulation factor XIII: a subunit structural locus

The distribution of the three previously reported alleles, with normal products at the factor XIII A subunit structural locus, FXIIIA*1, FXIIIA*2 and FXIIIA*4 has been studied in populations from the region extending from the Indonesian archipelago through Papua New Guinea, Australia and New Zealand to the Pacific Islands of Micronesia, Melanesia and Polynesia. In addition a population from the Caspian Littoral of Iran and a population of South American Indians were studied. The FXIIIA*1 and FXIIIA*2 alleles were polymorphic in all populations studied. The distribution of the FXIIIA*4 allele suggests that it may be a Melanesian marker.     

Molecular phylogeography of the fruit bat genus Melonycteris in northern Melanesia

Aim To investigate patterns of genetic divergence between populations of the fruit bat genus Melonycteris Dobson 1877 in relation to the possible effects on dispersal of the geological history of water barriers within and between northern Melanesian archipelagos. Location The genus is found only in the Bismarck Archipelago and Solomon Islands of northern Melanesia. Methods Up to 935 aligned bases of cytochrome b and cytochrome c oxidase subunit I DNA sequences were determined for specimens of most species and subspecies of Melonycteris. Measures of genetic distance, analysis of molecular variation and phylogenetic investigations (using maximum parsimony, maximum likelihood and Bayesian approaches) were conducted to assess the evolutionary relationships amongst populations. Results The deepest divergences within Melonycteris separate the genus into two reciprocally monophyletic clades from first, the Bismarck Archipelago, and secondly, the Solomon Islands. Within the Solomon Islands, five major clades received strong support. Listed in a generally north‐western to south‐eastern direction these were: (1) specimens from Choiseul and Santa Isabel; (2) specimens from New Georgia and Kolombangara; (3) specimens from Malaita; (4) specimens from Guadalcanal; and (5) specimens from Makira. Outgroup rooting suggested that the clade from Makira was the most basal within the Solomon Islands, being shown as the sister group to all other Melonycteris from this archipelago. Main conclusions Patterns of genetic variation within Melonycteris were generally consistent, given current knowledge of northern Melanesian geological history, with the hypothesis that the dispersal of these fruit bats is strongly inhibited by water barriers. Within the Solomon Islands the main genetic clades were each restricted to a single island or to a group of islands that are thought to have belonged to larger landmasses (Greater Gatumbangara and Greater Bukida) formed by land bridges during the Pleistocene. The high genetic distance between specimens from the Bismarck Archipelago and from the Solomon Islands reflects the persistently large geographic distance between these archipelagos. The unexpected phylogenetic position of the Makira specimens suggests either that this island was the first colonized by Melonycteris in the Solomon Islands or that this population is the relict of a clade that was previously more widely distributed.     

Prevalence of antibodies interactive with HTLV-I antigens in selected Solomon Islands populations

Serum samples obtained in 1986 from healthy individuals in three distinct Solomon Islands populations were screened for antibodies to human lymphotropic virus type I (HTLV-I). One of the populations tested lives on the remote Polynesian outlier atoll, Ontong Java. The other two groups, the Baegu and the Lau, are Melanesians living on Malaita, the most populous of the larger Solomon Islands. Eighty-eight of a total of 601 (14.6%) sera tested were repeatably reactive in an enzyme-linked immunosorbent assay (ELISA) that uses as antigen a lysate of HTLV-I viral particles. The prevalence of antibodies interactive with HTLV-I viral particles. The prevalence of antibodies interactive with HTLV-I antigens varied among the three groups, ranging from 8.5% (16/188) in the Baegu, through 13% (7/54) in the Lau, to 18.1% (65/359) among the Ontong Java population. The specificity of the screening ELISA was confirmed by protein immunoblot. No serum samples were obtained from children under 9 years of age. Although 121 of the 601 sera came from children between the ages of 9 and 19, none of these were reactive in the HTLV-I ELISA. Starting in the third decade, the prevalence of HTLV-I seropositivity increased with age, from 8.8% (10/113) between the ages of 20 and 29 to a peak of 25.9% (15/58) and 25% (15/60) in the sixth and seventh decade, respectively. This age-specific prevalence pattern is strikingly similar to that which is seen in populations where HTLV-I infection is endemic.     

Genetic control and dynamics of the cellular immune response to the human T-cell leukaemia virus, HTLV-I.

About 1% of people infected with the human T-cell leukaemia virus, type 1 (HTLV-I) develop a disabling chronic inflammatory disease of the central nervous system known as HTLV-I-associated myelopathy/tropical spastic paraparesis (HAM/TSP). Patients with HAM/TSP have a vigorous immune response to HTLV-I, and it has been widely suggested that this immune response, particularly the HTLV-I-specific cytotoxic T-lymphocyte (CTL) response, causes the tissue damage that is seen in HAM/TSP. In this paper we summarize recent evidence that a strong CTL response to HTLV-I does in fact protect against HAM/TSP by reducing the proviral load of HTLV-I. We conclude that HTLV-I is persistently replicating at a high level, despite the relative constancy of its genome sequence. These results imply that antiretroviral drugs could reduce the risk of HAM/TSP by reducing the viral load, and that an effective anti-HTLV-I vaccine should elicit a strong CTL response to the virus. The dynamic nature of the infection also has implications for the epidemiology and the evolution of HTLV-I.     

Tax mutation associated with tropical spastic paraparesis/human T-cell leukemia virus type I-associated myelopathy.

Tumaco, Colombia, is an area with elevated rates of tropical spastic paraparesis/human T-cell leukemia virus type I (HTLV-I)-associated myelopathy (TSP/HAM). We have identified a mutation in nucleotide 7959 of the tax gene of 14 Tumaco HTLV-I isolates (14 positive of 14 tested) that was present in 5 of 14 (35%) TSP/HAM patients from Japan and in 8 of 11 (72%) TSP/HAM patients from other geographic locations. In contrast, this mutation was found in only 2 of 21 (9.5%) HTLV-I-infected subjects outside of Tumaco who did not have TSP/HAM. tax clones with nucleotide mutations including one at nucleotide 7959 showed a greater ability to transactivate the HTLV-I U3 promoter. However, this effect was not observed when two clones that differed only in nucleotide 7959 were compared. These results suggest that HTLV-I-infected individuals carrying isolates with this tax mutation are at higher risk for developing TSP/HAM.     

Lack of tax diversity for tropical spastic paraparesis/human T-cell lymphotropic virus type 1 (HTLV-I) associated myelopathy development in HTLV-I-infected subjects in São Paulo, Brazil

The product of human T-cell lymphotropic virus type 1 (HTLV-1) tax gene has a transactivating effect of the viral and cellular gene expression. Genetic variations in this gene have been correlated with differences in clinical outcomes. Based upon its diversity, two closely related substrains, namely tax A and tax B, have been described. The tax A substrain has been found at a higher frequency among human T-cell leukemia virus type 1 (TSP/HAM) patients than among healthy HTLV-I-infected asymptomatic subjects in Japan. In this study, we determined the distribution of tax substrains in HTLV-I-infected subjects in the city of S?o Paulo, Brazil. Using the ACCII restriction enzyme site, we detected only tax A substrain from 48 TSP/HAM patients and 28 healthy HTLV-I carriers. The sequenced tax genes from nine TSP/HAM patients and five asymptomatic HTLV-I carriers showed a similar pattern of mutation, which characterizes tax A. Our results indicate that HTLV-I tax subtypes have no significant influences on TSP/HAM disease progression. Furthermore, monophyletic introduction of HTLV-I to Brazil probably occurred during the African slave trade many years ago.     

Evolutionary insights on the origin of human T-cell lymphoma/leukemia virus type I (HTLV-I) derived from sequence analysis of a new HTLV-I variant from Papua New Guinea.

Recent studies have established the presence of human T-cell lymphoma/leukemia virus type I (HTLV-I) in Melanesia. An HTLV-I strain, PNG-1, has now been isolated from a healthy member of the Hagahai, a remote, recently contacted group in Papua New Guinea. To further characterize PNG-1, we employed polymerase chain reaction amplification with subsequent cloning and sequencing of amplified products. Sequence analyses of amplified regions of pol, env, and pX genes of this variant indicate marked heterogeneity (approximately 7%) from prototype HTLV-I. Based on available sequence data, PNG-1 is distinct from all other known HTLV-I strains and diverges from the common ancestor of HTLV-I prior to prototype isolates. The data also suggest, therefore, that HTLV-I originated in the Indo-Malay region rather than Africa.     

Intersterility between populations of <Emphasis Type="Italic">Lentinula edodes</Emphasis> from Papua New Guinea

Mating tests among strains of Lentinula edodes distributed in Asia-Australasia were conducted. As a result, 26 strains were classified into three groups: 2 strains from Mt. Wilhelm in Papua New Guinea (PN1 group) showed intersterility with 7 strains from Mt. Albert Edward and Mt. Kaisenik in Papua New Guinea (PN2 group) and semicompatibility (clamp formation restricted to contact zone between paired monokaryons) with 17 strains from Asia-Australasia (AA group), whereas the strains of the PN2 group showed compatibility with the AA group. These results suggest that the shiitake populations distributed in Asia-Australasia including Papua New Guinea are in the process of speciation. Contribution no. 391 from the Tottori Mycological Institute