RESUMO
The indigenous North American mammalian schistosome Heterobilharzia americana has recently attracted attention for causing outbreaks in dogs in states outside of its southeastern U.S. distribution. Although H. americana has yet to be reported in New Mexico, we examined 2 New Mexico isolates of Galba snails to determine their susceptibility to experimental infection with an isolate of H. americana from Utah. One of the Galba isolates from the Rio Grande bosque in the Albuquerque suburb of Corrales was identified as Galba humilis, and like specimens of the same taxon from Utah, proved susceptible to H. americana (27.6% of exposed surviving snails positive). The second Galba isolate sourced from the northern mountains of New Mexico, which surprisingly was revealed to be Galba schirazensis based on cytochrome c oxidase 1, 16S rRNA, and the internal transcribed spacer 2 markers, was also susceptible to H. americana (56.3% of exposed surviving field-derived snails and 46.4% first generation [F1] snails positive). This is the first report of the latter snail being a compatible snail host for H. americana. As G. schirazensis has a wide, albeit spotty, distribution and is considered an invasive species, it provides yet another opportunity for H. americana to expand its known range, potentially including the state of New Mexico as well.
Assuntos
Schistosomatidae , Caramujos , Cães , Animais , New Mexico/epidemiologia , RNA Ribossômico 16S/genética , Caramujos/genética , Schistosomatidae/genética , Schistosoma , Mamíferos/genéticaRESUMO
To provide information to guide considerations of declaring interruption of transmission of human schistosomiasis due to Schistosoma mansoni on St. Lucia, we undertook an island-wide survey in June-July 2022 to determine the presence of Biomphalaria snails, the intermediate hosts of S. mansoni, and their infection status. Snail surveys were carried out at 58 habitats to determine presence of Biomphalaria snails followed by examination of the collected snails for evidence of infection with S. mansoni. Furthermore, water samples were collected at the snail habitats and screened for presence of S. mansoni DNA using an eDNA approach. We found B. glabrata present in one habitat (Cul de Sac) where it was abundant. Specimens provisionally identified as Biomphalaria kuhniana were recovered from 10 habitats. None of the Biomphalaria specimens recovered were positive for S. mansoni. None of the eDNA water samples screened were positive for S. mansoni. Experimental exposures of both field-derived and laboratory-reared St. Lucian B. glabrata and B. kuhniana to Puerto Rican and Kenyan-derived S. mansoni strains revealed B. glabrata to be susceptible to both and B. kuhniana proved refractory from histological and snail shedding results. We conclude, given the current rarity of B. glabrata on the island and lack of evidence for the presence of S. mansoni, that transmission is unlikely to be ongoing. Coupled with negative results from recent human serological surveys, and implementation of improved sanitation and provision of safe water supplies, St. Lucia should be considered a candidate for declaration of interruption of human schistosomiasis transmission.
Assuntos
Biomphalaria , Esquistossomose mansoni , Esquistossomose , Animais , Humanos , Schistosoma mansoni , Quênia , Santa Lúcia , Caramujos , Esquistossomose mansoni/epidemiologiaRESUMO
Investigations leading to a WHO-validated declaration of elimination of schistosomiasis transmission are contemplated for several countries, including Caribbean island nations. With assistance from the Pan American Health Organization, we undertook freshwater snail surveys in two such nations, Antigua and Barbuda, and Montserrat in September and October 2017. Historically, the transmission of Schistosoma mansoni supported by the Neotropical vector snail Biomphalaria glabrata occurred in both countries. Transmission on the islands is thought to have been interrupted by the treatment of infected people, improved sanitation, introduction of competitor snails, and on Montserrat with the eruption of the Soufrière volcano which decimated known B. glabrata habitats. Guided by the available literature and local expertise, we found Biomphalaria snails in seven of 15 and one of 14 localities on Antigua and Montserrat, respectively, most of which were identified anatomically and molecularly as Biomphalaria kuhniana. Two localities on Antigua harbored B. glabrata, but no schistosome infections in snails were found. For snail-related aspects of validation of elimination, there are needs to undertake basic local training in medical malacology, be guided by historical literature and recent human schistosomiasis surveys, improve and validate sampling protocols for aquatic habitats, enlist local expertise to efficiently find potential transmission sites, use both anatomical and molecular identifications of schistosomes or putative vector snail species found, if possible determine the susceptibility of recovered Biomphalaria spp. to S. mansoni, publish survey results, and provide museum vouchers of collected snails and parasites as part of the historical record.
Assuntos
Biomphalaria/parasitologia , Reservatórios de Doenças/parasitologia , Schistosoma mansoni/fisiologia , Esquistossomose mansoni/prevenção & controle , Animais , Antígua e Barbuda/epidemiologia , Biomphalaria/classificação , Biomphalaria/genética , Erradicação de Doenças , Geografia , Humanos , Filogenia , Esquistossomose mansoni/parasitologia , Esquistossomose mansoni/transmissão , Índias Ocidentais/epidemiologiaRESUMO
In the blood fluke family Schistosomatidae, marine snails are well known as intermediate hosts. Eight families of marine snails have thus far been reported to host schistosomes across the world, most of which have been implicated in human cercarial dermatitis (HCD) outbreaks. As part of our larger effort to define the species diversity and biology of schistosomes in Argentina, in particular their role in causing HCD, we searched in the marine pulmonate snail (Siphonaria lessoni) for a schistosome species described previously from S. lessoni from southern Argentina. Additionally, gulls (Larus dominicanus) collected from a different project locality (inland) were examined, because they are known to spend time in the intertidal regions. Schistosome sporocysts were found in S. lessoni, and a small worm fragment was retrieved from a gull. Molecular phylogenies for 28S, ITS1-5.8S-ITS2, and cox1 genes revealed that the specimens from the gull and S. lessoni grouped closely together, suggesting they are conspecifics. Also, ITS1-5.8S-ITS2 sequences suggested one of the schistosomes from S. lessoni and a schistosome from a South African penguin were also conspecifics. Further study is needed to verify if these specimens comprise a distinct marine clade within the larger avian schistosome clade that is comprised mostly of species using freshwater snail hosts. Thus far, it appears this group of marine schistosomes may be more likely found in the southern hemisphere. It is unclear if the observed distribution pattern of schistosomes in Siphonaria is a result of sampling bias and/or indicative of a specific bird-snail-schistosome association. It is clear they are sharply differentiated from the basal marine clade of avian schistosomes that includes Austrobilharzia.
Assuntos
Doenças das Aves/parasitologia , Charadriiformes/parasitologia , Filogenia , Schistosomatidae/classificação , Caramujos/parasitologia , Infecções por Trematódeos/veterinária , Animais , Argentina , Teorema de Bayes , Biodiversidade , DNA de Helmintos/química , DNA de Helmintos/isolamento & purificação , DNA Mitocondrial/genética , DNA Ribossômico/química , DNA Espaçador Ribossômico/química , Complexo IV da Cadeia de Transporte de Elétrons/genética , Lagos , Fígado/parasitologia , Veia Porta/parasitologia , RNA Ribossômico 28S/genética , RNA Ribossômico 5,8S/genética , Schistosomatidae/genética , Schistosomatidae/isolamento & purificação , Infecções por Trematódeos/parasitologiaRESUMO
Our current knowledge of avian schistosomes from South America is scarce in all respects, including species and generic diversity, their life cycles, patterns of host use, potential to cause dermatitis outbreaks, and evolutionary affinities. As a step towards addressing this shortcoming, the goal of this study was to provide discrete reference points relating to snail hosts, locality records, morphological attributes, sequence for nuclear 28S and ITS, and partial mitochondrial cox1 genes, and phylogenetic relationships for schistosome cercariae recovered from different species of Chilina, which are gastropods endemic to South America. In total, 1,308 snails belonging to 6 species of Chilina were collected from 12 localities across Argentina. Thirty-eight snails (2.9%) had schistosome infections. Our data indicate the presence of 3 lineages of Chilina-transmitted schistosomes, all of which group within the major avian schistosome clade. However, none of the lineages grouped within or as sister to other known avian schistosome genera in the tree, indicating they probably represent undescribed genera. The relationships of these schistosomes from Chilina spp. are discussed in relation to their position in the global schistosome phylogenetic tree.
Assuntos
Schistosoma/classificação , Schistosoma/fisiologia , Caramujos/parasitologia , Animais , Argentina , Doenças das Aves/parasitologia , Doenças das Aves/transmissão , Aves , Cercárias/classificação , Cercárias/genética , Cercárias/fisiologia , DNA de Helmintos/química , DNA de Helmintos/isolamento & purificação , Água Doce , Filogenia , Schistosoma/genética , Esquistossomose/parasitologia , Esquistossomose/transmissão , Esquistossomose/veterináriaRESUMO
To provide a novel resource for analysis of the genome of Biomphalaria glabrata, members of the international Biomphalaria glabrata Genome Initiative (biology.unm.edu/biomphalaria-genome.html), working with the Arizona Genomics Institute (AGI) and supported by the National Human Genome Research Institute (NHGRI), produced a high quality bacterial artificial chromosome (BAC) library. The BB02 strain B. glabrata, a field isolate (Belo Horizonte, Minas Gerais, Brasil) that is susceptible to several strains of Schistosoma mansoni, was selfed for two generations to reduce haplotype diversity in the offspring. High molecular weight DNA was isolated from ovotestes of 40 snails, partially digested with HindIII, and ligated into pAGIBAC1 vector. The resulting B. glabrata BAC library (BG_BBa) consists of 61824 clones (136.3 kb average insert size) and provides 9.05 × coverage of the 931 Mb genome. Probing with single/low copy number genes from B. glabrata and fingerprinting of selected BAC clones indicated that the BAC library sufficiently represents the gene complement. BAC end sequence data (514 reads, 299860 nt) indicated that the genome of B. glabrata contains ~ 63 percent AT, and disclosed several novel genes, transposable elements, and groups of high frequency sequence elements. This BG_BBa BAC library, available from AGI at cost to the research community, gains in relevance because BB02 strain B. glabrata is targeted whole genome sequencing by NHGRI.
Assuntos
Animais , Biomphalaria/genética , Cromossomos Artificiais Bacterianos , Biblioteca Gênica , Schistosoma mansoni/fisiologia , Biomphalaria/classificação , Biomphalaria/parasitologia , Impressões Digitais de DNA , Interações Hospedeiro-Parasita/genéticaRESUMO
To provide a novel resource for analysis of the genome of Biomphalaria glabrata, members of the international Biomphalaria glabrata Genome Initiative (http://biology.unm.edu/biomphalaria-genome.html), working with the Arizona Genomics Institute (AGI) and supported by the National Human Genome Research Institute (NHGRI), produced a high quality bacterial artificial chromosome (BAC) library. The BB02 strain B. glabrata, a field isolate (Belo Horizonte, Minas Gerais, Brasil) that is susceptible to several strains of Schistosoma mansoni, was selfed for two generations to reduce haplotype diversity in the offspring. High molecular weight DNA was isolated from ovotestes of 40 snails, partially digested with HindIII, and ligated into pAGIBAC1 vector. The resulting B. glabrata BAC library (BG_BBa) consists of 61824 clones (136.3 kb average insert size) and provides 9.05 x coverage of the 931 Mb genome. Probing with single/low copy number genes from B. glabrata and fingerprinting of selected BAC clones indicated that the BAC library sufficiently represents the gene complement. BAC end sequence data (514 reads, 299860 nt) indicated that the genome of B. glabrata contains ~ 63% AT, and disclosed several novel genes, transposable elements, and groups of high frequency sequence elements. This BG_BBa BAC library, available from AGI at cost to the research community, gains in relevance because BB02 strain B. glabrata is targeted whole genome sequencing by NHGRI.
Assuntos
Biomphalaria/genética , Cromossomos Artificiais Bacterianos , Biblioteca Gênica , Schistosoma mansoni/fisiologia , Animais , Biomphalaria/classificação , Biomphalaria/parasitologia , Impressões Digitais de DNA , Interações Hospedeiro-Parasita/genéticaRESUMO
Schistosoma mansoni is the most widespread of the human-infecting schistosomes, present in 54 countries, predominantly in Africa, but also in Madagascar, the Arabian Peninsula, and the Neotropics. Adult-stage parasites that infect humans are also occasionally recovered from baboons, rodents, and other mammals. Larval stages of the parasite are dependent upon certain species of freshwater snails in the genus Biomphalaria, which largely determine the parasite's geographical range. How S. mansoni genetic diversity is distributed geographically and among isolates using different hosts has never been examined with DNA sequence data. Here we describe the global phylogeography of S. mansoni using more than 2500 bp of mitochondrial DNA (mtDNA) from 143 parasites collected in 53 geographically widespread localities. Considerable within-species mtDNA diversity was found, with 85 unique haplotypes grouping into five distinct lineages. Geographical separation, and not host use, appears to be the most important factor in the diversification of the parasite. East African specimens showed a remarkable amount of variation, comprising three clades and basal members of a fourth, strongly suggesting an East African origin for the parasite 0.30-0.43 million years ago, a time frame that follows the arrival of its snail host. Less but still substantial variation was found in the rest of Africa. A recent colonization of the New World is supported by finding only seven closely related New World haplotypes which have West African affinities. All Brazilian isolates have nearly identical mtDNA haplotypes, suggesting a founder effect from the establishment and spread of the parasite in this large country.
Assuntos
Variação Genética , Filogenia , Schistosoma mansoni/genética , África , Animais , Arábia , Região do Caribe , DNA de Helmintos/genética , DNA Mitocondrial/genética , Feminino , Geografia , Haplótipos , Humanos , Madagáscar , Masculino , Análise de Sequência de DNA , América do SulRESUMO
Species of Ribeiroia (Trematoda: Psilostomidae) are known to cause severe limb malformations and elevated mortality in amphibians. However, little is known regarding the number of species in this genus or its relation to other taxa. Species of Ribeiroia have historically been differentiated by slight differences among their larval stages. To better understand the systematics and biogeography of this genus and their potential relevance to the distribution of malformed amphibians, specimens identified as Ribeiroia were collected across much of the known range, including samples from 5 states in the United States (8 sites) and 2 islands in the Caribbean (Puerto Rico and Guadeloupe). A cercaria from East Africa identified as Cercaria lileta (Fain, 1953), with attributes suggestive of Ribeiroia (possibly R. congolensis), was also examined. The intertranscribed spacer region 2 (ITS-2) of the ribosomal gene complex was sequenced and found to consist of 429 nucleotides (nt) for R. ondatrae (United States) and 427 nt for R. marini (Caribbean), with only 6 base differences noted between the 2 species. The ITS-2 region of C. lileta (429 nt) aligned closely with those of the 2 other Ribeiroia species in a phylogenetic analysis that included related trematode genera. This evidence suggests that a third Ribeiroia species exists in tropical Africa. Variation in ITS-2 within R. ondatrae was nonexistent among the 8 populations from North America. Our study further suggests that Ribeiroia spp. originally parasitized Biomphalaria sp., and that a host switch to a closely related snail, Helisoma sp., may have occurred in the lineage represented by R. ondatrae. However, relationships within the Echinostomatidae are not understood well enough to make any robust conclusions at this time.
Assuntos
Anfíbios , Deformidades Congênitas dos Membros/veterinária , Filogenia , Trematódeos/classificação , Infecções por Trematódeos/veterinária , Anfíbios/anormalidades , Anfíbios/parasitologia , Animais , DNA de Helmintos/química , DNA Espaçador Ribossômico/química , Quênia , Funções Verossimilhança , Deformidades Congênitas dos Membros/epidemiologia , Deformidades Congênitas dos Membros/parasitologia , Reação em Cadeia da Polimerase/veterinária , Alinhamento de Sequência/veterinária , Caramujos/parasitologia , Trematódeos/genética , Infecções por Trematódeos/complicações , Infecções por Trematódeos/epidemiologia , Infecções por Trematódeos/parasitologia , Estados Unidos/epidemiologia , Índias OcidentaisRESUMO
The icthyosporean, Capsaspora owczarzaki, a known predator of Schistosoma mansoni sporocysts in vitro, is more prevalent in laboratory-reared strains of the intermediate snail host, Biomphalaria glabrata resistant to S. mansoni, than from the susceptible M line strain. We examined whether B. glabrata resistant to the NIH-PR-1 strain of S. mansoni from 2 regions in Brazil were also host to C. owczarzaki. Symbiont presence was examined using hemolymph culturing and nested polymerase chain reaction of snail genomic DNA with primers designed to specifically amplify sequences from relatives of the Icthyosporea. All B. glabrata of the resistant Salvador strain from the laboratory of Dr. Lobato Paraense in Rio de Janeiro, Brazil (n = 46) tested negative for symbionts. Three of 18 semiresistant 10-R2 B. glabrata from the laboratory of Dr. Barbosa in Recife, Brazil tested positive for C. owczarzaki. Another icthyosporean, Anurofeca sp., was identified from 1, 10-R2 snail and from 2 of 12 field-collected B. glabrata from Praia do Forte Orange, Ilha de Itamaracá. Snails from 2 other sites, Hotel Colibri, Pontezinha and Praia do Sossego, Ilha de Itamaracá, were negative for Anurofeca. Two genera of ciliates were also identified. Paruroleptus sp. was found in 4, 10-R2 snails and Trichodina sp. was identified in 2 field-collected snails from Praia do Forte Orange and Praia do Sossego.