Parasitic and symbiotic relationships govern vast nutrient and energy flows, yet controversy surr... more Parasitic and symbiotic relationships govern vast nutrient and energy flows, yet controversy surrounds their longevity. Enduring relationships may engender parallel phylogenies among hosts and parasites, but so may ephemeral relationships when parasites colonize related hosts. An understanding of whether symbiont and host populations have grown and contracted in concert would be useful when considering the temporal durability of these relationships. Here, we devised methods to compare demographic histories derived from genomic data. We compared the historical growth of the agent of severe human malaria, <i>Plasmodium falciparum</i>, and its mosquito vector, <i>Anopheles gambiae</i>, to human and primate histories, thereby discerning long-term parallels and anthropogenic population explosions. The growth history of <i>Trichinella spiralis</i>, a zoonotic parasite disseminated by swine, proved regionally specific, paralleling distinctive growth hist...
DNA sequence analysis of a chicken interleukin (IL)-15 cDNA identified a 187 amino acid open read... more DNA sequence analysis of a chicken interleukin (IL)-15 cDNA identified a 187 amino acid open reading frame encoding a protein with a predicted molecular weight of 21,964Da, two potential N-linked glycosylation sites, four highly conserved Cys residues, two out-of-frame AUG initiation codons in the 5′ untranslated region, and an unusually long (66 amino acid) signal peptide such that the expected
The demand for an effective malaria vaccine is high, with millions of people being affected by th... more The demand for an effective malaria vaccine is high, with millions of people being affected by the disease every year. A large variety of potential vaccines are under investigation worldwide, and when tested in clinical trials, researchers need to extract as much data as ...
Infection, genetics and evolution : journal of molecular epidemiology and evolutionary genetics in infectious diseases, Jan 22, 2015
Hybridization between two closely related but distinct genetic lineages may lead to homogenizatio... more Hybridization between two closely related but distinct genetic lineages may lead to homogenization of the two lineages with potentially novel phenotypes, or selective pressure to avoid hybridization if the two lineages are truly distinct. Trichinella nativa and Trichinella T6 are zoonotic nematode parasites which can be distinguished genetically despite occasional hybridization. Here, using an experimental murine model, we attempt to determine whether there are barriers to hybridization when sizeable numbers of each lineage are allowed to coinfect a host. Two mice were independently infected with equal numbers of T. nativa and T6. The offspring of these coinfections were genotyped at two microsatellite loci and one mitochondrial locus capable of distinguishing T. nativa from T6 genotypes. Among larvae in the F1 generation, offspring of every possible mating were encountered. Most larvae (63.6%) derived from T. nativa×T. nativa matings, while 21.1% of offspring were the product of T6...
Eimeria parasites cause enteric disease in livestock and the closely related Cyclospora cayetanen... more Eimeria parasites cause enteric disease in livestock and the closely related Cyclospora cayetanensis causes human disease. Oocysts of these coccidian parasites undergo maturation (sporulation) before becoming infectious. Here, we assessed transcription in maturing oocysts of Eimeria acervulina, a widespread chicken parasite, predicted gene functions, and determined which of these genes also occur in C. cayetanensis. RNA-Sequencing yielded ~2 billion paired-end reads, 92% of which mapped to the E. acervulina genome. The ~6,900 annotated genes underwent temporally-coordinated patterns of gene expression. Fifty-three genes each contributed >1,000 transcripts per million (TPM) throughout the study interval, including cation-transporting ATPases, an oocyst wall protein, a palmitoyltransferase, membrane proteins, and hypothetical proteins. These genes were enriched for 285 gene ontology (GO) terms and 13 genes were ascribed to 17 KEGG pathways, defining housekeeping processes and funct...
Parasitic and symbiotic relationships govern vast nutrient and energy flows, yet controversy surr... more Parasitic and symbiotic relationships govern vast nutrient and energy flows, yet controversy surrounds their longevity. Enduring relationships may engender parallel phylogenies among hosts and parasites, but so may ephemeral relationships when parasites colonize related hosts. An understanding of whether symbiont and host populations have grown and contracted in concert would be useful when considering the temporal durability of these relationships. Here, we devised methods to compare demographic histories derived from genomic data. We compared the historical growth of the agent of severe human malaria, , and its mosquito vector, , to human and primate histories, thereby discerning long-term parallels and anthropogenic population explosions. The growth history of , a zoonotic parasite disseminated by swine, proved regionally specific, paralleling distinctive growth histories for wild boar in Asia and Europe. Parallel histories were inferred for an anemone and its algal symbiont ( an...
Sarcocystis sarcocysts are common in many species of domestic and wild animals. Here, we report s... more Sarcocystis sarcocysts are common in many species of domestic and wild animals. Here, we report sarcocystosis in muscles from 91 free range elk (Cervus elaphus) from Pennsylvania, USA, tested by histopathology, transmission electron microscopy (TEM), and DNA sequencing. Sarcocysts were detected in hematoxylin and eosin (HE)-stained sections from 83 of 91 (91.2%) elk, including 83/91 (91.2%) tongues and 15/17 (88.2%) hearts. With respect to age, sarcocysts were found in 0/5 calves, 8/9 (88.8%) yearlings, and 75/77 (97.4%) adults. Sarcocysts were identified in 62/69 (89.4%) females and 21/22 (91.2%) males. Associated lesions were mild and consisted of inflammatory foci around degenerate sarcocysts. There were two morphologically distinct sarcocysts based on wall thickness, thin (< 0.5 μm) and thick-walled (> 4.0 μm). Thin-walled sarcocysts had a TEM "type 2" and villar protrusions (vps), identical to Sarcocystis wapiti previously described from elk in western USA. This...
Toxoplasma gondii counts among the most consequential food-borne parasites, and although the para... more Toxoplasma gondii counts among the most consequential food-borne parasites, and although the parasite occurs in a wide range of wild and domesticated animals, farms may constitute a specific and important locus of transmission. If so, parasites in animals that inhabit agricultural habitats might be suspected of harbouring genetically distinct parasite types. To better understand habitat effects pertinent to this parasite's transmission, we compiled and analysed existing genotypic data of 623 samples from animals across a proximity gradient from areas of human settlement to the wilderness in North America. To facilitate such analysis, T. gondii isolates were divided into three groups: (i) from farm-bound animals (with the most limited home ranges on farms); (ii) from free-roaming animals (with wider home ranges on or near farms); and (iii) from wildlife. In addition, parasite genotype distribution in different animal species was analysed. We observed no absolute limitation of any...
While Sarcocystis parasites from the muscles of donkey and horse have been characterized as diffe... more While Sarcocystis parasites from the muscles of donkey and horse have been characterized as different species, similarities between the parasites in these host raises questions about this assignment (Levine and Tadros, 1980; Matuschka, 1983; Odening et al., 1995b). To resolve this, we examined the tissue cysts of Sarcocystis collected from donkeys and horses were studied by morphological and molecular methods. Morphological studies performed by light microscopy (LM) revealed that each of two types of cysts were present in samples from each host type. Under LM, villar protrusions (VP) were sometimes observed on the larger (Type I) and smaller (Type II) of these cyst types; when present, these were sometimes short and sometimes long. By electron microscopy (EM), VPs from both horse and donkey cysts were found to share similar structures, appearing to be typical of 'type 11a' VPs found on the Sarcocystis wall of Sarcocystis fayeri as described by Dubey et al., 1977. The VP of c...
Bovine besnoitiosis, caused by Besnoitia besnoiti, is an economically important disease of cattle... more Bovine besnoitiosis, caused by Besnoitia besnoiti, is an economically important disease of cattle in many countries but its transmission remains a mystery. Wild felids are suspected to be its definitive hosts. The domestic cat (Felis catus) is known experimental definitive host for Besnoitia species of rodents. Here, we report for Besnoitia darlingi the first identification of a natural definitive host, the bobcat (Lynx rufus). Oocysts resembling Toxoplasma gondii (unsporulated; 10.9±0.8×12.1±0.2μm; n=5) were detected microscopically in the feces of two of 25 free ranging wild bobcats from Mississippi, USA. After detailed investigation, we identified these oocysts as B. darlingi and not T. gondii. The IFN-γ gene knockout (KO) mice fed oocysts from bobcats died of acute besnoitiosis and tachyzoites were found in their tissues. Oocysts were also mildly pathogenic to outbred Swiss Webster mice (SW) (Mus musculus). The SW mice fed oocysts became ill but generally survived and developed ...
Rodents are intermediate hosts for many species of Sarcocystis. Little is known of Sarcocystis cy... more Rodents are intermediate hosts for many species of Sarcocystis. Little is known of Sarcocystis cymruensis that uses the Brown rat (Rattus norvegicus) as intermediate hosts and the domestic cat (Felis catus) as experimental definitive host. Here, we identified and described Sarcocystis cymruensis in naturally infected R. norvegicus from Grenada, West Indies. Rats (n = 167) were trapped in various locations in two parishes (St. George and St. David). Microscopic, thin (< 1 μm) walled, slender sarcocysts were found in 11 of 156 (7.0%) rats skeletal muscles by squash examination. A laboratory-raised cat fed naturally infected rat tissues excreted sporocysts that were infectious for interferon gamma gene knockout (KO) mice, but not to Swiss Webster outbred albino mice. All inoculated mice remained asymptomatic, and microscopic S. cymruensis-like sarcocysts were found in the muscles of KO mice euthanized on day 70, 116, and 189 post inoculation (p.i.). Sarcocysts from infected KO mice ...
Genome assemblies can form the basis of comparative analyses fostering insight into the evolution... more Genome assemblies can form the basis of comparative analyses fostering insight into the evolutionary genetics of a parasite's pathogenicity, host-pathogen interactions, environmental constraints and invasion biology; however, the length and complexity of many parasite genomes has hampered the development of well-resolved assemblies. In order to improve Trichinella genome assemblies, the genome of the sylvatic encapsulated species Trichinella murrelli was sequenced using third-generation, long-read technology and, using syntenic comparisons, scaffolded to a reference genome assembly of Trichinella spiralis, markedly improving both. A high-quality draft assembly for T. murrelli was achieved that totalled 63·2 Mbp, half of which was condensed into 26 contigs each longer than 571 000 bp. When compared with previous assemblies for parasites in the genus, ours required 10-fold fewer contigs, which were five times longer, on average. Better assembly across repetitive regions also enabl...
The muscles of herbivores commonly harbor sarcocysts of parasites belonging to species in the gen... more The muscles of herbivores commonly harbor sarcocysts of parasites belonging to species in the genus Sarcocystis, but such muscle parasites are rare in carnivores. Here, we report Sarcocystis arctica-like sarcocysts in muscles of Arctic foxes (Vulpes lagopus) from Alaska, USA, for the first time. The tongues of 56 foxes were examined for Sarcocystis infection using several methods. Sarcocystis bradyzoites were detected in pepsin digests of 13 (23.2%), and sarcocysts were found in histological sections stained with hematoxylin and eosin (HE) of 9 (16.0%). By light microscopy, sarcocysts were up to 4 mm long and up to 245 μm wide. In HE-stained sections, the sarcocyst wall appeared smooth and up to 1.5 μm thick without visible protrusions. By transmission electron microscopy, the sarcocyst wall had a wavy parasitophorous vacuolar membrane (pvm) folded as pleomorphic villar protrusions (vp), sometimes with anastomoses of villar tips. The vp and the ground substance (gs) layer were smoot...
Parasitic and symbiotic relationships govern vast nutrient and energy flows, yet controversy surr... more Parasitic and symbiotic relationships govern vast nutrient and energy flows, yet controversy surrounds their longevity. Enduring relationships may engender parallel phylogenies among hosts and parasites, but so may ephemeral relationships when parasites colonize related hosts. An understanding of whether symbiont and host populations have grown and contracted in concert would be useful when considering the temporal durability of these relationships. Here, we devised methods to compare demographic histories derived from genomic data. We compared the historical growth of the agent of severe human malaria, <i>Plasmodium falciparum</i>, and its mosquito vector, <i>Anopheles gambiae</i>, to human and primate histories, thereby discerning long-term parallels and anthropogenic population explosions. The growth history of <i>Trichinella spiralis</i>, a zoonotic parasite disseminated by swine, proved regionally specific, paralleling distinctive growth hist...
DNA sequence analysis of a chicken interleukin (IL)-15 cDNA identified a 187 amino acid open read... more DNA sequence analysis of a chicken interleukin (IL)-15 cDNA identified a 187 amino acid open reading frame encoding a protein with a predicted molecular weight of 21,964Da, two potential N-linked glycosylation sites, four highly conserved Cys residues, two out-of-frame AUG initiation codons in the 5′ untranslated region, and an unusually long (66 amino acid) signal peptide such that the expected
The demand for an effective malaria vaccine is high, with millions of people being affected by th... more The demand for an effective malaria vaccine is high, with millions of people being affected by the disease every year. A large variety of potential vaccines are under investigation worldwide, and when tested in clinical trials, researchers need to extract as much data as ...
Infection, genetics and evolution : journal of molecular epidemiology and evolutionary genetics in infectious diseases, Jan 22, 2015
Hybridization between two closely related but distinct genetic lineages may lead to homogenizatio... more Hybridization between two closely related but distinct genetic lineages may lead to homogenization of the two lineages with potentially novel phenotypes, or selective pressure to avoid hybridization if the two lineages are truly distinct. Trichinella nativa and Trichinella T6 are zoonotic nematode parasites which can be distinguished genetically despite occasional hybridization. Here, using an experimental murine model, we attempt to determine whether there are barriers to hybridization when sizeable numbers of each lineage are allowed to coinfect a host. Two mice were independently infected with equal numbers of T. nativa and T6. The offspring of these coinfections were genotyped at two microsatellite loci and one mitochondrial locus capable of distinguishing T. nativa from T6 genotypes. Among larvae in the F1 generation, offspring of every possible mating were encountered. Most larvae (63.6%) derived from T. nativa×T. nativa matings, while 21.1% of offspring were the product of T6...
Eimeria parasites cause enteric disease in livestock and the closely related Cyclospora cayetanen... more Eimeria parasites cause enteric disease in livestock and the closely related Cyclospora cayetanensis causes human disease. Oocysts of these coccidian parasites undergo maturation (sporulation) before becoming infectious. Here, we assessed transcription in maturing oocysts of Eimeria acervulina, a widespread chicken parasite, predicted gene functions, and determined which of these genes also occur in C. cayetanensis. RNA-Sequencing yielded ~2 billion paired-end reads, 92% of which mapped to the E. acervulina genome. The ~6,900 annotated genes underwent temporally-coordinated patterns of gene expression. Fifty-three genes each contributed >1,000 transcripts per million (TPM) throughout the study interval, including cation-transporting ATPases, an oocyst wall protein, a palmitoyltransferase, membrane proteins, and hypothetical proteins. These genes were enriched for 285 gene ontology (GO) terms and 13 genes were ascribed to 17 KEGG pathways, defining housekeeping processes and funct...
Parasitic and symbiotic relationships govern vast nutrient and energy flows, yet controversy surr... more Parasitic and symbiotic relationships govern vast nutrient and energy flows, yet controversy surrounds their longevity. Enduring relationships may engender parallel phylogenies among hosts and parasites, but so may ephemeral relationships when parasites colonize related hosts. An understanding of whether symbiont and host populations have grown and contracted in concert would be useful when considering the temporal durability of these relationships. Here, we devised methods to compare demographic histories derived from genomic data. We compared the historical growth of the agent of severe human malaria, , and its mosquito vector, , to human and primate histories, thereby discerning long-term parallels and anthropogenic population explosions. The growth history of , a zoonotic parasite disseminated by swine, proved regionally specific, paralleling distinctive growth histories for wild boar in Asia and Europe. Parallel histories were inferred for an anemone and its algal symbiont ( an...
Sarcocystis sarcocysts are common in many species of domestic and wild animals. Here, we report s... more Sarcocystis sarcocysts are common in many species of domestic and wild animals. Here, we report sarcocystosis in muscles from 91 free range elk (Cervus elaphus) from Pennsylvania, USA, tested by histopathology, transmission electron microscopy (TEM), and DNA sequencing. Sarcocysts were detected in hematoxylin and eosin (HE)-stained sections from 83 of 91 (91.2%) elk, including 83/91 (91.2%) tongues and 15/17 (88.2%) hearts. With respect to age, sarcocysts were found in 0/5 calves, 8/9 (88.8%) yearlings, and 75/77 (97.4%) adults. Sarcocysts were identified in 62/69 (89.4%) females and 21/22 (91.2%) males. Associated lesions were mild and consisted of inflammatory foci around degenerate sarcocysts. There were two morphologically distinct sarcocysts based on wall thickness, thin (< 0.5 μm) and thick-walled (> 4.0 μm). Thin-walled sarcocysts had a TEM "type 2" and villar protrusions (vps), identical to Sarcocystis wapiti previously described from elk in western USA. This...
Toxoplasma gondii counts among the most consequential food-borne parasites, and although the para... more Toxoplasma gondii counts among the most consequential food-borne parasites, and although the parasite occurs in a wide range of wild and domesticated animals, farms may constitute a specific and important locus of transmission. If so, parasites in animals that inhabit agricultural habitats might be suspected of harbouring genetically distinct parasite types. To better understand habitat effects pertinent to this parasite's transmission, we compiled and analysed existing genotypic data of 623 samples from animals across a proximity gradient from areas of human settlement to the wilderness in North America. To facilitate such analysis, T. gondii isolates were divided into three groups: (i) from farm-bound animals (with the most limited home ranges on farms); (ii) from free-roaming animals (with wider home ranges on or near farms); and (iii) from wildlife. In addition, parasite genotype distribution in different animal species was analysed. We observed no absolute limitation of any...
While Sarcocystis parasites from the muscles of donkey and horse have been characterized as diffe... more While Sarcocystis parasites from the muscles of donkey and horse have been characterized as different species, similarities between the parasites in these host raises questions about this assignment (Levine and Tadros, 1980; Matuschka, 1983; Odening et al., 1995b). To resolve this, we examined the tissue cysts of Sarcocystis collected from donkeys and horses were studied by morphological and molecular methods. Morphological studies performed by light microscopy (LM) revealed that each of two types of cysts were present in samples from each host type. Under LM, villar protrusions (VP) were sometimes observed on the larger (Type I) and smaller (Type II) of these cyst types; when present, these were sometimes short and sometimes long. By electron microscopy (EM), VPs from both horse and donkey cysts were found to share similar structures, appearing to be typical of 'type 11a' VPs found on the Sarcocystis wall of Sarcocystis fayeri as described by Dubey et al., 1977. The VP of c...
Bovine besnoitiosis, caused by Besnoitia besnoiti, is an economically important disease of cattle... more Bovine besnoitiosis, caused by Besnoitia besnoiti, is an economically important disease of cattle in many countries but its transmission remains a mystery. Wild felids are suspected to be its definitive hosts. The domestic cat (Felis catus) is known experimental definitive host for Besnoitia species of rodents. Here, we report for Besnoitia darlingi the first identification of a natural definitive host, the bobcat (Lynx rufus). Oocysts resembling Toxoplasma gondii (unsporulated; 10.9±0.8×12.1±0.2μm; n=5) were detected microscopically in the feces of two of 25 free ranging wild bobcats from Mississippi, USA. After detailed investigation, we identified these oocysts as B. darlingi and not T. gondii. The IFN-γ gene knockout (KO) mice fed oocysts from bobcats died of acute besnoitiosis and tachyzoites were found in their tissues. Oocysts were also mildly pathogenic to outbred Swiss Webster mice (SW) (Mus musculus). The SW mice fed oocysts became ill but generally survived and developed ...
Rodents are intermediate hosts for many species of Sarcocystis. Little is known of Sarcocystis cy... more Rodents are intermediate hosts for many species of Sarcocystis. Little is known of Sarcocystis cymruensis that uses the Brown rat (Rattus norvegicus) as intermediate hosts and the domestic cat (Felis catus) as experimental definitive host. Here, we identified and described Sarcocystis cymruensis in naturally infected R. norvegicus from Grenada, West Indies. Rats (n = 167) were trapped in various locations in two parishes (St. George and St. David). Microscopic, thin (< 1 μm) walled, slender sarcocysts were found in 11 of 156 (7.0%) rats skeletal muscles by squash examination. A laboratory-raised cat fed naturally infected rat tissues excreted sporocysts that were infectious for interferon gamma gene knockout (KO) mice, but not to Swiss Webster outbred albino mice. All inoculated mice remained asymptomatic, and microscopic S. cymruensis-like sarcocysts were found in the muscles of KO mice euthanized on day 70, 116, and 189 post inoculation (p.i.). Sarcocysts from infected KO mice ...
Genome assemblies can form the basis of comparative analyses fostering insight into the evolution... more Genome assemblies can form the basis of comparative analyses fostering insight into the evolutionary genetics of a parasite's pathogenicity, host-pathogen interactions, environmental constraints and invasion biology; however, the length and complexity of many parasite genomes has hampered the development of well-resolved assemblies. In order to improve Trichinella genome assemblies, the genome of the sylvatic encapsulated species Trichinella murrelli was sequenced using third-generation, long-read technology and, using syntenic comparisons, scaffolded to a reference genome assembly of Trichinella spiralis, markedly improving both. A high-quality draft assembly for T. murrelli was achieved that totalled 63·2 Mbp, half of which was condensed into 26 contigs each longer than 571 000 bp. When compared with previous assemblies for parasites in the genus, ours required 10-fold fewer contigs, which were five times longer, on average. Better assembly across repetitive regions also enabl...
The muscles of herbivores commonly harbor sarcocysts of parasites belonging to species in the gen... more The muscles of herbivores commonly harbor sarcocysts of parasites belonging to species in the genus Sarcocystis, but such muscle parasites are rare in carnivores. Here, we report Sarcocystis arctica-like sarcocysts in muscles of Arctic foxes (Vulpes lagopus) from Alaska, USA, for the first time. The tongues of 56 foxes were examined for Sarcocystis infection using several methods. Sarcocystis bradyzoites were detected in pepsin digests of 13 (23.2%), and sarcocysts were found in histological sections stained with hematoxylin and eosin (HE) of 9 (16.0%). By light microscopy, sarcocysts were up to 4 mm long and up to 245 μm wide. In HE-stained sections, the sarcocyst wall appeared smooth and up to 1.5 μm thick without visible protrusions. By transmission electron microscopy, the sarcocyst wall had a wavy parasitophorous vacuolar membrane (pvm) folded as pleomorphic villar protrusions (vp), sometimes with anastomoses of villar tips. The vp and the ground substance (gs) layer were smoot...
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