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S.I. Jarvi

Publications and source records attributed to S.I. Jarvi.

10 recordsLinked to original sources
USGS2013

Next-generation sequencing reveals cryptic mtDNA diversity of Plasmodium relictum in the Hawaiian Islands

Next-generation 454 sequencing techniques were used to re-examine diversity of mitochondrial cytochrome b lineages of avian malaria (Plasmodium relictum) in Hawaii. We document a minimum of 23 variant lineages of the parasite based on single nucleotide transitional changes, in addition to the previously reported single lineage (GRW4). A new, publicly available portal (Integroomer) was developed for initial parsing of 454 datasets. Mean variant prevalence and frequency was higher in low elevation Hawaii Amakihi (Hemignathus virens) with Avipoxvirus-like lesions (P = 0·001), suggesting that the variants may be biologically distinct. By contrast, variant prevalence and frequency did not differ significantly among mid-elevation Apapane (Himatione sanguinea) with or without lesions (P = 0·691). The low frequency and the lack of detection of variants independent of GRW4 suggest that multiple independent introductions of P. relictum to Hawaii are unlikely. Multiple variants may have been introduced in heteroplasmy with GRW4 or exist within the tandem repeat structure of the mitochondrial genome. The discovery of multiple mitochondrial lineages of P. relictum in Hawaii provides a measure of genetic diversity within a geographically isolated population of this parasite and suggests the origins and evolution of parasite diversity may be more complicated than previously recognized.

Hawai'i↗
USGS2008

Protective efficacy of a recombinant subunit West Nile virus vaccine in domestic geese (Anser anser)

Introduction of the West Nile virus (WNV) to Hawai'i will undoubtedly devastate many populations of critically endangered avian species indigenous to Hawai'i. The protective efficacy of a protein-based WNV subunit vaccine formulated with adjuvant was evaluated in domestic geese as a surrogate species for the endangered Ne??ne??, the state bird of Hawai'i. Prevention of viremia following viral infection of vaccinated birds was used as the clinical endpoint of protection. ELISA and plaque reduction neutralization tests demonstrate that significant levels of vaccine antigen-specific antibody were produced in groups of birds vaccinated with 5 or 10 ??g of the WN-80E antigen formulated with ISA720 adjuvant. Moreover, after challenge with WNV, no viremia was detected in vaccinated birds, whereas viremia was detected up to 4 days after and virus was detected by oral swab for 6 days after infection among control groups. Safe and effective vaccination of managed or captive endangered bird populations will protect species with critically low numbers that could not survive the added mortality of introduced disease. ?? 2008 Elsevier Ltd.

Hawai'i↗
USGS2008

Genetic characterization of Hawaiian isolates of Plasmodium relictum reveals mixed-genotype infections

Background: The relatively recent introduction of a highly efficient mosquito vector and an avian pathogen (Plasmodium relictum) to an isolated island ecosystem with nai??ve, highly susceptible avian hosts provides a unique opportunity to investigate evolution of virulence in a natural system. Mixed infections can significantly contribute to the uncertainty in host-pathogen dynamics with direct impacts on virulence. Toward further understanding of how host-parasite and parasite-parasite relationships may impact virulence, this study characterizes within-host diversity of malaria parasite populations based on genetic analysis of the trap (thrombospondin-related anonymous protein) gene in isolates originating from Hawaii, Maui and Kauai Islands. Methods: A total of 397 clones were produced by nested PCR amplification and cloning of a 1664 bp fragment of the trap gene from two malarial isolates, K1 (Kauai) and KV115 (Hawaii) that have been used for experimental studies, and from additional isolates from wild birds on Kauai, Maui and Hawaii Islands. Diversity of clones was evaluated initially by RFLP-based screening, followed by complete sequencing of 33 selected clones. Results: RFLP analysis of trap revealed a minimum of 28 distinct RFLP haplotypes among the 397 clones from 18 birds. Multiple trap haplotypes were detected in every bird evaluated, with an average of 5.9 haplotypes per bird. Overall diversity did not differ between the experimental isolates, however, a greater number of unique haplotypes were detected in K1 than in KV115. We detected high levels of clonal diversity with clear delineation between isolates K1 and KV115 in a haplotype network. The patterns of within-host haplotype clustering are consistent with the possibility of a clonal genetic structure and rapid within-host mutation after infection. Conclusion: Avian malaria (P. relictum) and Avipoxvirus are the significant infectious diseases currently affecting the native Hawaiian avifauna. This study shows that clonal diversity of Hawaiian isolates of P. relictum is much higher than previously recognized. Mixed infections can significantly contribute to the uncertainty in host-pathogen dynamics with direct implications for host demographics, disease management strategies, and evolution of virulence. The results of this study indicate a widespread presence of multiple-genotype malaria infections with high clonal diversity in native birds of Hawaii, which when coupled with concurrent infection with Avipoxvirus, may significantly influence evolution of virulence. ?? 2008 Jarvi et al; licensee BioMed Central Ltd.

Biology Direct↗
USGS2007

Diversity, origins and virulence of Avipoxviruses in Hawaiian Forest Birds

We cultured avian pox (Avipoxvirus spp.) from lesions collected on Hawai'i, Maui, Moloka'i, and 'Oahu in the Hawaiian Islands from 15 native or non-native birds representing three avian orders. Phylogenetic analysis of a 538 bp fragment of the gene encoding the virus 4b core polypeptide revealed two distinct variant clusters, with sequences from chickens (fowlpox) forming a third distinct basal cluster. Pox isolates from one of these two clusters appear closely related to canarypox and other passerine pox viruses, while the second appears more specific to Hawai'i. There was no evidence that birds were infected simultaneously with multiple pox virus variants based on evaluation of multiples clones from four individuals. No obvious temporal or geographic associations were observed and strict host specificity was not apparent among the 4b-defined field isolates. We amplified a 116 bp 4b core protein gene fragment from an 'Elepaio (Chasiempis sandwichensis) collected in 1900 on Hawai'i Island that clustered closely with the second of the two variants, suggesting that this variant has been in Hawai'i for at least 100 years. The high variation detected between the three 4b clusters provides evidence for multiple, likely independent introductions, and does not support the hypothesis of infection of native species through introduction of infected fowl. Preliminary experimental infections in native Hawai'i 'Amakihi (Hemignathus virens) suggest that the 4b-defined variants may be biologically distinct, with one variant appearing more virulent. These pox viruses may interact with avian malaria (Plasmodium relictum), another introduced pathogen in Hawaiian forest bird populations, through modulation of host immune responses. ?? 2007 Springer Science+Business Media B.V.

Conservation Genetics↗
USGS2004

Natural selection of the major histocompatibility complex (Mhc) in Hawaiian honeycreepers (Drepanidinae)

The native Hawaiian honeycreepers represent a classic example of adaptive radiation and speciation, but currently face one the highest extinction rates in the world. Although multiple factors have likely influenced the fate of Hawaiian birds, the relatively recent introduction of avian malaria is thought to be a major factor limiting honeycreeper distribution and abundance. We have initiated genetic analyses of class II ?? chain Mhc genes in four species of honeycreepers using methods that eliminate the possibility of sequencing mosaic variants formed by cloning heteroduplexed polymerase chain reaction products. Phylogenetic analyses group the honeycreeper Mhc sequences into two distinct clusters. Variation within one cluster is high, with dN > d S and levels of diversity similar to other studies of Mhc (B system) genes in birds. The second cluster is nearly invariant and includes sequences from honeycreepers (Fringillidae), a sparrow (Emberizidae) and a blackbird (Emberizidae). This highly conserved cluster appears reminiscent of the independently segregating Rfp-Y system of genes defined in chickens. The notion that balancing selection operates at the Mhc in the honeycreepers is supported by transpecies polymorphism and strikingly high dN/dS ratios at codons putatively involved in peptide interaction. Mitochondrial DNA control region sequences were invariant in the i'iwi, but were highly variable in the 'amakihi. By contrast, levels of variability of class II ?? chain Mhc sequence codons that are hypothesized to be directly involved in peptide interactions appear comparable between i'iwi and 'amakihi. In the i'iwi, natural selection may have maintained variation within the Mhc, even in the face of what appears to a genetic bottleneck.

Molecular Ecology↗
USGS2001

Evaluation of the major histocompatibility complex (Mhc) in cranes: applications to conservation efforts

Although there have been heated discussions concerning the relative importance of using Mhc diversity as a basis for selecting breeders in conservation projects, most parties agree that the genetic variability residual in an endangered species should be maintained through genetic management, if at all possible. Substantial evidence exists (particularly in birds) documenting the influences of specific Mhc haplotypes on disease outcome and also that those individuals which are heterozygous for Mhc alleles appear to have an advantage for survival over those that are homozygous. Thus, conservation of genetic variability of the Mhc is likely important for the preservation of fitness, especially in small breeding populations. More than half of the world's crane species are listed as endangered. Members of all 15 known species are represented among breeding animals for captive propagation at the International Crane Foundation (Wisconsin) and the USGS Patuxent Wildlife Research Center (Maryland). Collaborative multi-organization efforts and the availability of extensive pedigree records have allowed the study of Mhc variability in several species of cranes. We have found, for example, that Mhc diversity in the captive Florida sandhill crane (Grus canadensis pratensis) population appears high, whereas in the captive whooping crane (Grus americana), which has undergone a severe 'genetic bottleneck,? both the number of alleles and the levels of heterozygosity appear to be substantially reduced.

Book chapter↗
USGS2000

Application of a PCR-based approach to identify sex in Hawaiian honeycreepers (Drepanidinae)

The application of molecular techniques to conservation genetics issues can provide important guidance criteria for management of endangered species. The results from this study establish that PCR-based approaches for sex determination developed in other bird species (Griffiths and Tiwari 1995; Griffiths et al. 1996, 1998; Ellegren 1996) can be applied with a high degree of confidence to at least four species of Hawaiian honeycreepers. This provides a rapid, reliable method with which population managers can optimize sex ratios within populations of endangered species that are subject to artificial manipulation through captive breeding programmes or geographic translocation.

Hawai'i↗
USGS1999

Identification, inheritance, and linkage of B-G-like and MHC class I genes in cranes

We identified B-G -like genes in the whooping and Florida sandhill cranes and linked them to the major histocompatibility complex (MHC). We evaluated the inheritance of B-G -like genes in families of whooping and Florida sandhill cranes using restriction fragment patterns (RFPs). Two B-G -like genes, designated wcbg1 and wcbg2 , were located within 8 kb of one another. The fully sequenced wcbg2 gene encodes a B-G -IgV-like domain, an additional Ig-like domain, a transmembrane domain, and a single heptad domain typical of α-helical coiled coils. Patterns of restriction fragments in DNA from the whooping crane and from a number of other species indicate that the B-G -like gene families of cranes are large with diverse sequences. Segregation of RFPs in families of Florida sandhill cranes provide evidence for genetic polymorphism in the B-G -like genes. The restriction fragments generally segregated in concert with MHC haplotypes assigned by serological typing and by single stranded conformational polymorphism (SSCP) assays based in the second exon of the crane MHC class I genes. This study supports the concept of a long-term association of polymorphic B-G -like genes with MHC. It also establishes SSCP as a means for evaluating MHC genetic variability in cranes.

Journal of Heredity↗
USGS1995

A complex alloantigen system in Florida sandhill cranes, Grus canadensis pratensis: Evidence for the major histocompatibility (B) system

The B blood group system constitutes the major histocompatibility complex ( Mhc ) in birds. The Mhc is a cluster of genes largely devoted to the processing and presentation of antigen. The Mhc is highly polymorphic in many species and, thus, useful in the evaluation of genetic diversity for fitness traits within populations of a variety of animals. Correlations found between particular Mhc haplotypes and resistance to certain diseases emphasize the importance of understanding the functional significance of diversity of the Mhc , particularly in species threatened with extinction. As part of studies focused on genetic diversity in wild birds, serological techniques were used to define a highly polymorphic alloantigen system in seven families of Florida sandhill cranes ( Grus canadensis pratensis ). The results of analyses with antisera produced within the crane families and with chicken Mhc antigen-specific reagents revealed a single major alloantigen system that is likely the Mhc of the Florida sandhill crane. Preliminary experiments indicate that these crane alloantisera will provide a means of defining the Mhc in other species of cranes.

Journal of Heredity↗