Showing papers in "Journal of Parasitology in 2021"
TL;DR: A large trematode biodiversity survey performed across 3 yr on 6 lakes in Alberta confirmed 3 already-reported snail hosts for 7 North American avian schistosomes; however, the cytochrome c oxidase subunit 1 (COI) nucleotide sequence from 1 cercarial sample (from a single specimen of Planorbella trivolvis) was distinct from all other COI schistsome sequences.
Abstract: Freshwater gastropods of the genera Lymnaea Lamarck, 1799, Physa Draparnaud, 1801, Gyraulus Charpentier, 1837, Radix Montfort, 1810, and Stagnicola Jeffreys, 1830 are considered suitable intermediate hosts for avian schistosomes A large trematode biodiversity survey performed across 3 yr on 6 lakes in Alberta confirmed 3 already-reported snail hosts for 7 North American avian schistosomes; however, the cytochrome c oxidase subunit 1 (COI) nucleotide sequence from 1 cercarial sample (from a single specimen of Planorbella trivolvis) was distinct from all other COI schistosome sequences As part of a simultaneous, comparable study of P trivolvis by us in Michigan, we collected another cercarial type from 6 lakes that was 99% similar (COI) to the aforementioned cercarial type Phylogenetic analyses of the COI and 28S rDNA genes recovered the former cercaria in a clade of avian schistosomes In Michigan, the feces of a Canada goose (Branta canadensis Linnaeus, 1758) had a miracidium with an identical COI nucleotide sequence Preliminary swimmer's itch and cercarial emergence studies were performed to determine if the cercariae could cause swimmer's itch and to study the emergence pattern as compared with species of Trichobilharzia Skrjabin and Zakharow, 1920
12 citations
TL;DR: In this paper, the authors investigated whether the global expansion of P. gralli flukes is associated with the spread of invasive snails M. tuberculata and T. granifera.
Abstract: Philophthalmus is a genus of globally distributed parasitic eye flukes with some members of the genus found in disparate locales. In particular, Philophthalmus gralli, a zoonotic trematode, appears to be a relatively new introduction to the Americas, facilitated by spillover from the invasive snails Melanoides tuberculata (red-rimmed melania) and Tarebia granifera (quilted melania), which were introduced via the aquarium trade, and perhaps furthered by avian dispersal. Given that two known intermediate hosts of Philophthalmus flukes are actively expanding their range as a result of human activities, we hypothesize that this spread is also associated with the spread of Philophthalmus flukes. To address this, we systematically reviewed the literature and examined whether the global expansion of P. gralli flukes is associated with the spread of invasive snails M. tuberculata and T. granifera. Here, we show that (1) specimens of P. gralli are only found in intermediate snail hosts M. tuberculata or T. granifera, suggesting intermediate host specificity for these 2 species, and (2) specimens of P. gralli have rarely been found outside the ranges (native and introduced) of M. tuberculata or T. granifera. Given the importance of distribution information of parasites in the role of identifying parasite invasions, we also review the known distribution of all Philophthalmus species. Considering recent outbreaks in humans and wild and domestic animal species, the continued spread of Philophthalmus presents a potential threat to veterinary and public health and conservation.
10 citations
TL;DR: In this article, the authors reviewed prevalence, persistence of infection, clinical disease, epidemiology, and public health risks of T. gondii infections in deer and other cervids for the past decade.
Abstract: Toxoplasma gondii infections are common in humans and animals worldwide. The ingestion of food or water contaminated with oocysts excreted by infected cats or ingestion of uncooked or undercooked meat containing tissue cysts of T. gondii are the 2 major modes of transmission of T. gondii. Deer are a popular game. Recently, outbreaks of clinical toxoplasmosis were reported in humans in North America linked to ingestion of undercooked venison. Here, we review prevalence, persistence of infection, clinical disease, epidemiology, and public health risks of T. gondii infections in deer and other cervids for the past decade. Estimates of worldwide serological prevalence are summarized individually for each species of deer, elk, moose, and caribou. Genetic diversity of 112 viable isolates of T. gondii from cervids is discussed, including its public health significance. Prevalence of T. gondii in deer is very high. Any part of a deer, including liver, spleen, and muscles, should be cooked thoroughly before human consumption.
9 citations
TL;DR: In this article, the identity of 2 lepocreadiid digenean species belonging in the genus Opechona Looss, 1907 that infect littoral fishes of the northern Gulf of Mexico was investigated.
Abstract: This study investigated the identity of 2 lepocreadiid digenean species belonging in the genus Opechona Looss, 1907 that infect littoral fishes of the northern Gulf of Mexico. Opechona chloroscombri Nahhas and Cable, 1964, a species previously known only from the Caribbean Sea and the Atlantic Ocean off Brazil, is reported herein from the Atlantic bumper, Chloroscombrus chrysurus (L.), in the northern Gulf of Mexico. A second species infects the gulf butterfish, Peprilus burti Fowler, and the American harvestfish, Peprilus paru (L.), and it is described as a new species that occurs in coastal waters of the north-central and northeastern Gulf of Mexico. Metacercariae infecting the mesoglea of pelagic jellyfishes (Bougainvillia carolinensis [McCady], Chrysaora quinquecirrha [Desor], and Stomolophus meleagris Agassiz) and pelagic comb jellies (Mnemiopsis leidyi Agassiz and Beroe ovata Bruguiere) were collected that resemble the new species but require further study to identify. Newly generated sequence fragments (28S rDNA) from both species of Opechona plus 2 other lepocreadiids collected during the study were aligned with publicly available sequences from 18 other lepocreadiids, 6 species of Aephnidiogenidae Yamaguti, 1934, and 2 species of Gorgocephalidae Manter, 1966. The alignment was subjected to Bayesian inference analysis rooted using a gorgocephalid. The resulting tree estimated the positions of both Opechona spp. as being unresolved within a group of taxa that included all available species of Opechona plus available species from the morphologically similar genera Prodistomum Linton, 1910, Preptetos Pritchard, 1960, and Clavogalea Bray, 1985. Although relatively similar in morphology, the 2 studied species of Opechona were surprisingly not closely related. Opechona cablei (Stunkard, 1980) Bray and Gibson, 1990 is herein considered to be a junior synonym of Opechona pyriformis (Linton, 1900) Bray and Gibson, 1990.
8 citations
TL;DR: The Posthovitellinum psiloterminae n. gen., n. sp. as discussed by the authors is the first lissorchiid reported from the Mekong River; only the second from southern Vietnam; and the fourth reported from a cyprinid fish in Vietnam.
Abstract: Herein we describe a new species and propose a new genus, Posthovitellinum psiloterminae n. gen., n. sp. (Lissorchiidae: Asymphylodorinae), based on specimens that infect the intestine of Cyclocheilos enoplos (Bleeker, 1849) (Cypriniformes: Cyprinidae), a migratory riverine carp from the Mekong River (Dong Thap province, Vietnam). The new species is assigned to Lissorchiidae by having a combination of features: spinous tegument, subterminal oral sucker, pre-equatorial ventral sucker, median and pretesticular ovary, submarginal genital pore at level of the ventral sucker, follicular vitellarium distributing in 2 lateral fields, and lacking eyespot pigment in the adult. It cannot be assigned to any existing asymphylodorine genus because it has the combination of a well-developed cirrus-sac, an unarmed ejaculatory duct and metraterm, a follicular vitellarium distributing in 2 lateral fields located between the posterior margin of the ventral sucker and the mid-level of the testis, and a sinistral, submarginal genital pore. The new species has an elongate, claviform cirrus-sac, a single, large, elongate-oval testis at the posterior extremity of the body, operculate eggs, and an I-shaped excretory bladder with secondary branches at the level of the testis and extending anteriad to the level of the pharynx. Bayesian inference analysis of the partial large subunit ribosomal DNA gene (28S rDNA) recovered the new species sister to Asaccotrema vietnamienseSokolov and Gordeev, 2019; these species differed by 118 nucleotides (12%; 983 bp fragment). This is the first lissorchiid reported from the Mekong River; only the second from southern Vietnam; and the fourth reported from a cyprinid fish in Vietnam. The aforementioned phylogenetic analysis included previously unpublished sequences representing lissorchiids infecting the intestine of North American suckers (Cypriniformes: Catostomidae): Lissorchis cf. nelsoni from spotted sucker; Minytrema melanops (Rafinesque, 1820) and Lissorchis cf. gullaris (immature) from smallmouth buffalo, Ictiobus bubalus (Rafinesque, 1818). Asymphylodora atherinopsidisAnnereaux, 1947, herein is treated as a species incertae sedis. The 28S tree topology suggests that Lissorchiinae may comprise more than 1 lineage, but additional species are needed to confidently assert this.
8 citations
TL;DR: In this article, a new Herpetodiplostomus species was described from Geoffroy's side-necked turtle Phrynops geoffroanus from Mato Grosso State, Brazil, based on the distribution of vitellarium, level of development of holdfast papillae, and ratio of prosoma:opisthosoma width.
Abstract: As presently recognized, Herpetodiplostomum is a small genus of proterodiplostomid digeneans parasitic in crocodilians. Most members of Cheloniodiplostomum, a genus of proterodiplostomids that parasitize chelonians, were originally placed within Herpetodiplostomum. The 2 genera were distinguished based on the presence/absence of papillae on the holdfast organ and anterior extent of vitellarium. Our study of Herpetodiplostomum and Cheloniodiplostomum revealed a lack of consistent morphological differences between the genera. Therefore, we consider Cheloniodiplostomum to be a junior synonym of Herpetodiplostomum. Recent molecular phylogenetic studies included a number of proterodiplostomid taxa; however, DNA sequence data are not available for any Herpetodiplostomum or Cheloniodiplostomum species. Herein, we describe a new Herpetodiplostomum species from Geoffroy's side-necked turtle Phrynops geoffroanus from Mato Grosso State, Brazil. The new species can be distinguished from other Herpetodiplostomum species based on the distribution of vitellarium, level of development of holdfast papillae, and ratio of prosoma:opisthosoma width, among other characters. We provide the first molecular phylogeny of the Proterodiplostomidae that includes a Herpetodiplostomum species. The limited geographic distribution of Herpetodiplostomum spp. within the geographic ranges of caimans suggests a secondary host switching event from crocodilians to chelonian definitive hosts in the evolution of Herpetodiplostomum.
8 citations
TL;DR: The role of invertebrates in some acanthocephalan life cycles is unclear because juvenile acanthomorphs are difficult to identify to species using morphology as mentioned in this paper, however, laboratory studies of the life cycle suggest that ostracods and snails are both required hosts.
Abstract: The role of invertebrates in some acanthocephalan life cycles is unclear because juvenile acanthocephalans are difficult to identify to species using morphology. Most reports suggest acanthocephalans from turtle definitive hosts use ostracods as intermediate hosts and snails as paratenic hosts. However, laboratory studies of the life cycle suggest that ostracods and snails are both required hosts in the life cycle. To elucidate the role of ostracods and snails in acanthocephalan life cycles better, we collected 558 freshwater snails of 2 species, including Planorbella cf. Planorbella trivolvis and Physa acuta, from 23 wetlands in Oklahoma, U.S.A., and examined them for acanthocephalan infections. Additionally, we examined 37,208 ostracods of 4 species, Physocypria sp. (morphotype 1), Cypridopsis sp., Stenocypris sp., and Physocypria sp. (morphotype 2) for juvenile acanthocephalans from 2 wetlands in Oklahoma. Juvenile acanthocephalans were morphologically characterized, and the complete internal transcribed spacer (ITS) region of nuclear rDNA was sequenced from acanthocephalans infecting 11 ostracod and 13 snail hosts. We also sampled 10 red-eared slider turtles, Trachemys scripta elegans, and 1 common map turtle, Graptemys geographica, collected from Oklahoma, Arkansas, and Texas and recovered 1,854 adult acanthocephalans of 4 species. The ITS of 17 adult acanthocephalans of 4 species from turtle hosts were sequenced and compared to juvenile acanthocephalan sequences from ostracod and snail hosts from this study and GenBank to determine conspecificity. Of the 23 locations sampled for snails, 7 (30%) were positive for juvenile acanthocephalans in the genus Neoechinorhynchus. The overall prevalence and mean intensity of acanthocephalans in Planorbella cf. P. trivolvis and P. acuta were 20% and 2 (1-6) and 2% and 1 (1), respectively. In contrast, only 1 of 4 species of ostracods, Physocypria sp. (morphotype 1), was infected with larval/juvenile Neoechinorhynchus spp. with an overall prevalence of 0.1% and a mean intensity of 1 (1-2). Although 4 species of acanthocephalans infected turtle definitive hosts, including Neoechinorhynchus chrysemydis, Neoechinorhynchus emydis, Neoechinorhynchus emyditoides, and Neoechinorhynchus pseudemydis, all the ITS sequences from cystacanths infecting snail hosts were conspecific with N. emydis. In contrast, the ITS sequences from larval/juvenile acanthocephalans from ostracods were conspecific with 2 species of acanthocephalans from turtles (N. emydis and N. pseudemydis) and 1 species of acanthocephalan from fish (Neoechinorhynchus cylindratus). These results indicate that N. emydis infects freshwater snails, whereas other species of Neoechinorhynchus appear not to infect snail hosts. We document new ostracod and snail hosts for Neoechinorhynchus species, including the first report of an ostracod host for N. pseudemydis, and we provide novel molecular barcodes that can be used to determine larva, juvenile, and adult conspecificity of Neoechinorhynchus species.
8 citations
TL;DR: Zhang et al. as mentioned in this paper reported the first description of Blastocystis infection in peafowls in China, and two genetically distinct subtypes (STs) were determined: ST9 and ST7.
Abstract: This study is the first description of Blastocystis infection in peafowls in China. In total, 143 fecal specimens collected from a peafowl breeding farm in Henan Province were tested for Blastocystis infection by PCR assay targeting the small subunit ribosomal RNA (SSU rRNA) gene, and a total of 50 specimens (35.0%) were positive. Based on sequences and phylogenetic analysis, 2 genetically distinct subtypes (STs) were determined: ST9 and ST7. ST9 was the predominant subtype, accounting for 82% (41/50). The rare zoonotic subtype ST7 was also identified in peafowls, with the infection rate of 18% (9/50). Altogether, the present study is the first report of the prevalence and molecular characteristics of Blastocystis in peafowls in central China. The presence of zoonotic subtypes in peafowls suggests the potential risk of zoonotic transmission of Blastocystis to workers at peafowl farms.
7 citations
TL;DR: In this paper, a review compiles DNA vaccine efforts against Toxoplasma gondii, segmenting the analysis by parasite antigen, as well as a review of concomitant adjuvant usage.
Abstract: Toxoplasma gondii is an apicomplexan parasite that affects both humans and livestock. Transmitted to humans through ingestion, it is the second-leading cause of foodborne illness-related death. Currently, there exists no approved vaccine for humans or most livestock against the parasite. DNA vaccines, a type of subunit vaccine which uses segments of the pathogen's DNA to generate immunity, have shown varying degrees of experimental efficacy against infection caused by the parasite. This review compiles DNA vaccine efforts against Toxoplasma gondii, segmenting the analysis by parasite antigen, as well as a review of concomitant adjuvant usage. No single antigenic group was consistently more effective within in vivo trials relative to others.
7 citations
TL;DR: In this article, the authors reviewed prevalence, persistence of infection, clinical disease, epidemiology, and genetic diversity of T. gondii infections in wild rodents worldwide, and tabulated by country, by each rodent species alphabetically, and chronologically.
Abstract: Toxoplasma gondii infections are common in humans and animals worldwide. Rodents are one of the most important intermediate hosts for T. gondii because they are preyed on by cats, who in turn excrete the environmentally resistant oocysts in their feces and thus spread the infection. Information on T. gondii infections is spread in numerous reports and is not easily accessible to readers. Here, we review prevalence, persistence of infection, clinical disease, epidemiology, and genetic diversity of T. gondii infections in wild rodents worldwide. Data are tabulated by country, by each rodent species alphabetically, and chronologically. Recent genetic diversity of T. gondii strains in rodents is critically evaluated.
7 citations
TL;DR: In this paper, the authors examined the role of nonimmunological barriers (the exoskeleton and its openings) in avoiding infection by Dauer larvae and L2-L3 larvae, or whether these larval stages evade the host immune system in the same way.
Abstract: The immune response of animals, including insects, is overcome by some parasites. For example, dauer larvae (DL) of the obligate entomopathogenic nematodes (EPNs) Heterorhabditis and Steinernema can invade insects, evade their defenses, and cause death. Although DL were long assumed to be the only infective stage of nematodes, recent reports suggest that L2-L3 larvae of facultative EPNs are also capable of killing insects. There are no studies, to our knowledge, about the role of nonimmunological barriers (the exoskeleton and its openings) in avoiding infection by DL and L2-L3 larvae, or whether these larval stages evade the host immune system in the same way. The objective of this study was to examine these questions by infecting Galleria mellonella with the facultative parasitic nematode Rhabditis regina. DL or L2-L3 larvae were either deposited on or near the moths or injected into their hemocoel. Once nematodes reached the hemocoel, the following host immune response parameters were quantified: prophenoloxidase, phenoloxidase, lytic activity, and the number of granular hemocytes. DL showed a greater ability to penetrate the exoskeleton than L2-L3 larvae. Once inside, however, both went unnoticed by the immune system and killed the insect. A higher number of granular hemocytes was activated by L2-L3 larvae than DL. We show for the first time that L2-L3 larvae can penetrate and evade the insect immune system. Further research is needed to compare facultative and specialized EPNs to determine which is more likely, with both DL and L2-L3 larvae, to evade insect defense barriers and produce death. The results will contribute to understanding the evolution of virulence in entomopathogenic nematodes.
TL;DR: In this article, the efficacy of subcutaneous injection of ivermectin for the treatment of Parascaris spp. infection in foals and to identify the ParASCaris species present in the west and north of Iceland was investigated.
Abstract: Horses in Iceland have been isolated for more than 1,000 yr but still harbor a similar range of gastrointestinal parasites as do horses across the world. The long isolation of the horses and their parasites presumably means that no resistance genes have been introduced into the Parascaris spp. population. It is therefore of particular interest to investigate the efficacy of ivermectin on Parascaris spp. infecting Icelandic foals. Potential treatment failure of ivermectin in Iceland will add substantial new information on how resistance can arise independently. This study aimed to determine the efficacy of subcutaneous injection of ivermectin for the treatment of Parascaris spp. infection in foals and to identify the Parascaris species present in the west and north of Iceland. A fecal egg count reduction (FECR) test (FECRT) was performed on 50 foals from 8 farms, including an untreated control group of 6 foals, from September to November 2019. The foals were between 3 and 5 mo of age at the start of the study and had not previously been treated with anthelmintic drugs. Each foal was treated subcutaneously with off-label use of Ivomec® injection 10 mg/ml or Noromectin® 1% at a dose of 0.2 mg/kg. The FECR for each farm was calculated in 2 ways, by the eggCounts package in R and by the Presidente formula (FECRT). Both calculation methods resulted in efficacy levels between 0% and 80.78%, indicating ivermectin resistance on all farms. We also confirmed, by karyotyping, that the species of equine ascarid present in the west and north of Iceland is Parascaris univalens. This study provides evidence for treatment failure of ivermectin against P. univalens infection in foals. Since Icelandic horses have been isolated on the island for more than 1,000 yr, this implies that resistance alleles have developed independently in the Icelandic Parascaris population. The actual clinical impact of ivermectin resistance is unknown but another drug of choice should be considered to treat Parascaris infection in foals in Iceland.
TL;DR: In this paper, the relative compatibility of B. sudanica and B. choanomphala with S. mansoni miracidia was investigated, and the authors found that B. chakanophala is more compatible with S mansoni than B.sudanica.
Abstract: Schistosoma mansoni, which causes human intestinal schistosomiasis, continues to be a major public health concern in the Lake Victoria basin in western Kenya, with Biomphalaria sudanica (a shoreline inhabiting snail) and Biomphalaria choanomphala (a deep-water snail) playing roles in transmission. A recent study showed that B. sudanica was abundantly present near all study villages on the lakeshore, but B. choanomphala was significantly more abundant near villages known to be persistent transmission hotspots. The present study investigated the relative compatibility of B. sudanica and B. choanomphala with S. mansoni. A reciprocal cross-infection experiment used young adult F1 generation B. sudanica and B. choanomphala that were exposed to either 1, 5, or 10 sympatric or allopatric human-derived S. mansoni miracidia. Three weeks post-exposure (PE) and weekly thereafter, the snails were counted and screened for schistosome cercariae, and at 7 wk PE, total cercariae shed during a 2 hr period by each infected snail was determined. Pre-patent periods for S. mansoni in both B. sudanica and B. choanomphala were similar, and most snails in all exposure combinations started shedding cercariae 5 wk PE. Prevalences were significantly higher in B. choanomphala (12.2-80.9%) than in B. sudanica (5.2-18.6%) at each dose, regardless of whether miracidia were of an allopatric or a sympatric source (P < 0.0001). Overall, the odds of a snail becoming infected with 5 or 10 miracidia were significantly higher than the odds of being infected with 1 miracidium, (P < 0.0001), and fewer cercariae were produced by snails exposed to single as compared to 5 or 10 miracidia. On average, B. choanomphala produced more cercariae ( = 458, SD = 414) than B. sudanica ( = 238, SD = 208) (P < 0.0001). These results suggest that B. choanomphala is more compatible with S. mansoni than B. sudanica. Though B. choanomphala can be found in shallow shoreline waters, it is, for the most part, a deeper-water taxon. Because dredging is a relatively inefficient means of sampling, B. choanomphala is likely underestimated with respect to its population size, the number of S. mansoni-positive snails, and its role in maintaining transmission.
TL;DR: Cardicola Short, 1953 is the most speciose aporocotylid genus (35 species) and includes marine and estuarine species of fish blood flukes that infect higher ray-finned fishes (Euteleostei).
Abstract: Cardicola Short, 1953 is the most speciose aporocotylid genus (35 species) and includes marine and estuarine species of fish blood flukes that infect "higher ray-finned fishes" (Euteleostei) Several clades within Cardicola are recovered in phylogenetic analyses of the large subunit ribosomal DNA (28S), but morphological synapomorphies for those nucleotide-based clades remain elusive The type species, Cardicola cardiocola (Manter, 1947) Short, 1953, has not been recollected in 73 yr and the original description was incomplete; making a genus revision challenging because of the ambiguous systematic position of its type species Herein, we redescribe C cardiocola by using the holotype (USNM 1337732) and new specimens collected from the type host, jolthead porgy, Calamus bajonado (Sparidae), from nearby the type locality It differs from its congeners by the combination of having a body that is 5 times longer than wide, an anterior sucker with concentric rows of spines, 2-6 tegumental body spines per row, an esophageal gland that is 22-43% of the esophageal length, a testis that is 3-5 times longer than wide and that fills the intercecal space, a vitelline duct connecting to the anterior aspect of the ootype, an ascending uterus that lacks any coil, a descending uterus yielding a single coil, an obvious cirrus sac separated by constriction from the seminal vesicle, a tegumental protrusion surrounding the terminal end of cirrus sac, and a male genital pore that is posterior to the remainder of the genitalia We also describe a new congener infecting the heart of yellowedge grouper, Hyporthodus flavolimbatus (Serranidae), from the Gulf of Mexico It differs from its congeners by the combination of having an anterior sucker that does not extend beyond the anterior body margin, 2-5 tegumental body spines per row, posterior ceca that are 9 times length of the anterior ceca and that lack any coil, a testis that is 3 times longer than wide and that does not fill the intercecal space, an ovary that is >60% of the body width, a vitelline duct that connects to the anterior aspect of the ootype, a uterus that is >10% of the body width and that extends posterior to all genitalia, and a rounded posterior body margin It is the first species of Cardicola to be described from a grouper (Serranidae) The 28S and internal transcribed spacer 2 phylogenetic analyses recovered the new species as a distinct lineage within the clade of Cardicola spp
TL;DR: In this paper, the occurrence of C. felis infections in healthy cats was investigated, and piroplasm forms were seen in the erythrocytes of two cats, and C. feline DNA was identified by polymerase chain reaction (PCR) in one of them.
Abstract: Feline cytauxzoonosis is a disease caused by Cytauxzoon felis, a protozoan that infects the red blood cells and macrophages. It is responsible for an acute and often fatal disease in domestic cats. The purpose of this study was to investigate the occurrence of C. felis infections in healthy cats. Piroplasm forms were seen in the erythrocytes of 2 cats, and C. felis DNA was identified by polymerase chain reaction (PCR) in one of them. The results demonstrate that erythrocytic piroplasmids associated with tick-borne parasitic protozoa may be found circulating in the blood of healthy cats in Rio de Janeiro. These can be differentiated from the morphologically similar forms of species such as Babesia by analysis of DNA, thereby demonstrating the potential for further studies of feline populations in Brazil.
TL;DR: Wang et al. as mentioned in this paper used nested-PCR amplification of the partial small-subunit (SSU) rRNA gene to determine the prevalence of Cryptosporidium spp. in pet hamsters.
Abstract: Cryptosporidium spp. have been identified in a wide range of hosts, such as humans and domestic and wild animals, while less information about the prevalence of Cryptosporidium spp. in pet hamsters is documented. A total of 351 dwarf winter white Russian hamsters' fecal specimens were collected from 6 pet markets from the cities of Luzhou and Ziyang in Sichuan province in the southwestern part of China. The prevalence of Cryptosporidium spp. determined with nested-PCR amplification of the partial small-subunit (SSU) rRNA gene was 39.32% (138/351). The highest prevalence of Cryptosporidium spp. was in pet market 5 (79.49%, 62/78), followed by pet market 6 (38.64%, 17/44). The lowest prevalence of Cryptosporidium spp. was observed in pet market 3 (14.89%, 7/47). Statistically significant differences in the prevalence of Cryptosporidium spp. were observed among different pet markets (χ2 = 76.386, df = 5, P < 0.05), and a further post hoc test revealed that only pet market 5 was significantly different from other pet markets. Molecular analysis showed that 4 different Cryptosporidium species or genotypes were identified: Cryptosporidium parvum (n = 127), Cryptosporidium chipmunk genotype III (n = 6), Cryptosporidium andersoni (n = 4), and Cryptosporidium wrairi (n = 1). The identification of Cryptosporidium spp. was further tested with the 60-kDa glycoprotein (GP60) gene, and the positive rate was 29.7% (41/138). This is the first molecular report on Cryptosporidium spp. infection in dwarf winter white Russian hamsters in China. With C. parvum and C. andersoni being identified in both humans and pet hamsters, these findings suggest that pet hamsters may be potential reservoirs of zoonotic Cryptosporidium species and subtypes.
TL;DR: In this paper, a genotyping method was used to identify three distinct genotypes of the Hepatozoon species in ranid frogs from Ontario, Canada, including H catesbianae and H clamatae.
Abstract: Intraerythrocytic gamonts of at least 2 named Hepatozoon species have been reported to infect the erythrocytes of ranid frogs in Ontario, Canada Although gamonts of both species are morphometrically similar, the cytopathological changes that 1 of these species, Hepatozoon clamatae, causes to host erythrocytes, manifested by nuclear fragmentation, was used historically to distinguish this parasite from Hepatozoon catesbianae Molecular characterization of these 2 Hepatozoon species has been equivocal in correlating genotype with gamont morphotype Amplification and sequencing of multiple potential genotyping loci within the nuclear (18S ribosomal deoxyribonucleic acid [rDNA]; internal transcribed spacer 1), apicoplast (23S rDNA), and mitochondrial genomes (complete genomes, cytochrome c oxidase subunits I and III [COI and COIII], and cytochrome b) were conducted on Hepatozoon species that infect ranid frogs in Ontario Sequence data were then used to evaluate the diversity of parasites present in these amphibian hosts and to assign genotypes to gamont morphotypes, if possible Three distinct genotypes were identified at all loci; the data permitted the discovery of a third, formerly unrecognized Hepatozoon species in ranid frogs from Ontario Although all genetic loci demonstrated differences between Hepatozoon species, mitochondrial COIII sequences were most suitable for genotypic differentiation of these parasites of frogs Linking genotypes to gamont morphotypes proved impossible; genotypes identified as H catesbianae and H clamatae were found in infections with or without nuclear fragmentation of their host erythrocytes This suggests that differentiating these species must rely on suitable genotyping methods for identification in the blood of their amphibian intermediate hosts
TL;DR: In this article, the authors assessed the impact of treatment of uncomplicated malaria with Artesunate-Amodiaquine (AS+AQ) on molecular markers of antimalarial resistance.
Abstract: The use of Amodiaquine monotherapy is associated with the selection of molecular markers of Plasmodium falciparum resistance to chloroquine (pfcrt and pfmdr1). The decrease in sensitivity and the emergence of P. falciparum resistant to artemisinin-based combination therapy have been reported. Therefore, it is important to assess the impact of treatment of uncomplicated malaria with Artesunate-Amodiaquine (AS+AQ) on molecular markers of antimalarial resistance. We used standard World Health Organization (WHO) protocols to determine the in vivo efficacy of the combination (AS+AQ). In total, 170 subjects were included in the study. The molecular analysis focused on 168 dried blood spots. The aims were to determine the frequency of pfcrt 76T and pfmdr1 86Y mutations and the rates of reinfection using polymorphism markers msp1, msp2, and microsatellite markers (CA1, Ta87, TA99). Nested-PCR was used, followed in some cases by a restriction digestion. The level of P. falciparum clinical response was 92.9% (156/168) of Adequate Clinical and Parasitological Response (ACPR) before molecular correction and 97.0% (163/168) after molecular correction (P = 0.089). The frequency of mutation point pfcrt 76T was 76.2% (128/168) before treatment and 100% (7/7) after treatment (P = 0.1423). For the pfmdr1 mutation, the frequency was 28% (47/168) before treatment and 60% (6/10) after treatment (P = 0.1124). The rate of pfcrt 76T + pfmdr1 86Y was 22% (37/168) before and 50% (6/12) after treatment (P = 0.1465). Despite the presence of AS in the combination, AS+AQ selects for pfcrt 76T and pfmdr1 86Y mutant P. falciparum in Guinea.
TL;DR: In this paper, the authors compared oocyst counts in fresh feces and litter of broilers kept in floor pens with fresh pine shavings as litter material for 42 days.
Abstract: Counting oocysts in feces or litter is 1 method to monitor infection levels with Eimeria spp. in chickens after experimental infection or in commercial flocks. Counts of oocysts shed in the feces are thought to follow a typical pattern, with clear peaks representing infection cycles while oocyst counts in litter are representative for at least 2 wk before they begin to deteriorate. The objective of the study was to compare oocyst counts in fresh feces and litter of broilers kept in floor pens with fresh pine shavings as litter material for 42 days. The birds were spray-vaccinated against coccidia in the hatchery. Every 2 to 3 days, 7 pens were sampled by collecting fresh feces and litter from at least 3 locations per pen. Oocysts were counted using a McMaster chamber (Vetslides, Park City, Utah). There were significant differences between pens in oocyst counts in feces as well as in litter, and there were no obvious shedding patterns. Overall, the geometric mean of oocyst counts on day 8 and later was 1,300 oocysts per gram (opg) in feces and 2,700 opg in litter. The variability was lower in litter samples, and the number of pens required to find significant differences between groups in a hypothetical experiment was unrealistically high on most days. Investigating individual fecal samples showed large differences within the pens in addition to the differences between the pens.
TL;DR: A helminthological analysis was performed on 91 specimens of the porkfish, Anisotremus virginicus (Linnaeus) (Haemulidae), captured in coral reef habitats of the Parque Nacional Sistema Arrecifal Veracruzano (PNSAV).
Abstract: A helminthological analysis was performed on 91 specimens of the porkfish, Anisotremus virginicus (Linnaeus) (Haemulidae), captured in coral reef habitats of the Parque Nacional Sistema Arrecifal Veracruzano (PNSAV) (Veracruz Reef System National Park), in Veracruz, Mexico. A total of 22 helminth taxa were recorded: 9 digeneans, 6 monogeneans, 1 cestode, 4 nematodes, and 2 acanthocephalans. From the 22 taxa, 11 are new host records and 7 are new geographic records. The highest prevalence was found for Monorchis latus Manter, 1942 (69%), and Mexicana anisotremumCezar, Paschoal and Luque, 2012 (68%), and the highest mean intensity was found for M. anisotremum (19.6), M. latus (18.9), and Dollfusentis chandleri Golvan, 1969 (10.8). Other important values were the component community richness (S = 22), diversity (Shannon index H' = 1.6), and infracommunity level (S = 3.1 ± 1.4; Brillouin index, H = 0.52 ± 0.3), which were similar to those found in other marine fish at the same study site. Our result represents a significant range extension for several helminth taxa. The parasite communities of A. virginicus rank among the richer parasite communities of neotropical marine fishes. In addition, the results reveal the PNSAV is a diverse area for the parasite assemblage of neotropical reef marine fishes, particularly of haemulids but also for other fish families.
TL;DR: In this paper, the enigmatic Cathariotrema selachii (MacCallum, 1916) was redescribed based on the holotype, paratypes, and newly collected specimens infecting the olfactory organ of 5 shark species from the Gulf of Mexico.
Abstract: We herein redescribe the enigmatic Cathariotrema selachii (MacCallum, 1916) Johnston and Tiegs, 1922 based on the holotype, paratypes, and newly collected specimens infecting the olfactory organ of 5 shark species from the Gulf of Mexico (all new host records): scalloped hammerhead shark, Sphyrna lewini (Griffith and Smith, 1834) (Carcharhiniformes: Sphyrnidae); great hammerhead shark, Sphyrna mokarran (Ruppell, 1837); blacktip shark, Carcharhinus limbatus (Muller and Henle, 1839) (Carcharhiniformes: Carcharhinidae); spinner shark, Carcharhinus brevipinna (Muller and Henle, 1839); and Atlantic sharpnose shark, Rhizoprionodon terraenovae (Richardson, 1836) (Carcharhinidae). These specimens were morphologically indistinguishable from each other and from MacCallum's holotype and paratypes. Those sequenced had identical first internal transcribed spacer (ITS1) and large subunit ribosomal DNA (28S) nucleotide sequences. As such, C. selachii infects sharks of 2 orders (Carcharhiniformes, Lamniformes) and 3 families (Carcharhinidae, Sphyrnidae, Lamnidae) in the Northwestern Atlantic Ocean (type locality) and Gulf of Mexico (new records herein). This report is the first of new specimens of C. selachii in the Atlantic Ocean Basin in 95 yr and corrects long-standing error cascades and ambiguities concerning the morphology and systematic placement of C. selachii. Considering morphology and nucleotide-based phylogenetic evidence (28S, Bayesian analysis), we herein emend monotypic CathariotremaJohnston and Tiegs, 1922 and propose Cathariotrematinae Bullard n. subfam. for it and 4 other genera (all formerly assigned to Merizocotylinae Johnston and Tiegs, 1922). These genera comprise species infecting only the nose of sharks (monotypic Cathariotrema, SqualotremaKearn and Green, 1983 and SeptitremaKheddam, Chisholm, and Tazerouti, 2020 plus 3 species of TriloculotremaKearn, 1993) and nose of a chimaera (monotypic HolocephalocotyleDerouiche, Neifar, Gey, Justine, and Tazerouti, 2019). Cathariotrematinae differs from Merizocotylinae by having a 3-part attachment organ and by lacking open loculi that symmetrically encircle a cluster of >2 loculi in the center of the haptor. Monophyletic Cathariotrematinae (with sequences representing species of Cathariotrema, Triloculotrema, and Holocephalocotyle only) was sister to monophyletic Merizocotylinae, which together were sister to monophyletic Calicotylinae Monticelli, 1903. These subfamilies comprise a monophyletic group of monocotylids that have a double vagina and infect extrabranchial, enclosed niches (urogenital system, body cavity, olfactory chamber/nose) on their shark, ray, and chimaera hosts (all other monocotylids have a single vagina and infect the gill or body surfaces of rays only). Monocotylinae Taschenberg, 1879 and Decacotylinae Chisholm, Wheeler, and Beverley-Burton, 1995 were recovered as monophyletic. Heterocotylinae Chisholm, Wheeler, and Beverley-Burton, 1995 remained paraphyletic. We accept ParacalicotyleSzidat, 1970.
TL;DR: The first myxozoan reported from C. elongatus was reported in this paper, where seven adults were collected by hoop nets from the Red River, Little River County, and the Black River, Lawrence County (n = 4), Arkansas, and their gills, gallbladders, fins, integument, other major organs, and musculature were examined for myxozoans.
Abstract: During 9-10 February 2018 and 21-22 February 2020, 7 adult Blue Suckers, Cycleptus elongatus, were collected by hoop nets from the Red River, Little River County (n = 3), and the Black River, Lawrence County (n = 4), Arkansas, and their gills, gallbladders, fins, integument, other major organs, and musculature were examined for myxozoans. All 7 (100%) were infected with an unknown species of gill-infecting Myxobolus sp. Twenty formalin-fixed plasmodia (cysts) of Myxobolus cloutmani n. sp. were elliptoidal, 407 μm long × 270 μm wide. Formalin-fixed myxospores were orbicular to broadly elliptoidal, 8.7 μm long × 7.8 μm wide. Two polar capsules were pyriform and subequal in size, extending over halfway in the myxospore. The larger polar capsule was 5.5 μm long × 3.1 μm wide, while the shorter was 5.1 × 2.9 μm. A coiled polar filament possessed 5 or 6 coils. The myxospore was 3.7 μm thick in sutural view, with a distinct sutural ridge. Qualitative and quantitative morphological data were from formalin-fixed as well as ethanol-preserved spores, while molecular data consisted of a 2,010 base pair sequence of the partial 18S ribosomal RNA gene and a 2,502 base pair sequence of the partial 28S ribosomal RNA gene. Phylogenetic analysis grouped M. cloutmani n. sp. with the other catostomid-infecting myxobolids. This is the first myxozoan reported from C. elongatus.
TL;DR: In this paper, a phylogenetic analysis of the Litomosoides genus is presented, which includes species that as adults occur in the thoracic and abdominal cavity of mammalian hosts and are presumably vectored by mites.
Abstract: The genus Litomosoides Chandler, 1931, includes species that as adults occur in the thoracic and abdominal cavity of mammalian hosts and are presumably vectored by mites. The vertebrate hosts include a variety of Neotropical mammals such as phyllostomid and mormoopid bats; cricetid, sciurid, and hystricognath rodents; and didelphid marsupials. It has been suggested that Litomosoides is not a monophyletic group and that rampant horizontal transfer explains their presence in disparate groups of mammals. Herein we present a phylogenetic reconstruction including mitochondrial genes of 13 vouchered species. This phylogeny is used to reconstruct the evolutionary history of these parasites and the ancestral states of key characters used in species classification, namely, the configuration of the spicules. The historical association of these filarioids with 6 groups of mammals, as well as their ancestral geographic distributions, were reconstructed using Bayesian statistical approaches comparing alternative models of biogeography and evolution and fossil states in selected nodes of the phylogeny. The optimal reconstruction suggests a model of dispersal, extinction, and cladogenesis (DEC) driving the evolution of Litomosoides; the results suggest an origin of Litomosoides in South America and association of ancestors with phyllostomids, and strong evidence of at least 2 host-switching events: 1 of these involving cricetid rodents and the other mormoopid bats. The latter event included a simultaneous geographic expansion of the parasite lineage across South and North America. The host-switching event from phyllostomid bats into cricetid rodents occurred once these rodents diversified across South America; subsequent diversification of the latter clade resulted in 2 branches, each showing expansion of the parasites back into North America. This result suggests that both parasites and cricetid rodents established an association in South America, underwent diversification, and then dispersed into North America. Further, this clade of cricetid-dwelling species includes parasites featuring the "sigmodontis" spicule type. The identification of a single host-switching event involving the disparate lineages of Chiroptera and Rodentia offers a framework to reconstruct the gene evolution and diversification of this lineage after the host-switching event. This will help in predicting the ability of these parasites to infect sympatric mammals.
TL;DR: Overall, T. gondii isolates in bears range from those circulating in a domestic cycle to those mainly associated with wildlife (such as genotypes #4 and #5, together known as haplogroup 12), which suggest relatively high genetic diversity of T. Gondii in bears.
Abstract: Toxoplasma gondii infections are common in humans and animals worldwide. The present review summarizes worldwide information on the prevalence of clinical and subclinical infections, epidemiology, and genetic diversity of T. gondii infections in bears. Seroprevalence estimates of T. gondii in black bears (Ursus americanus) are one of the highest of all animals. In Pennsylvania, seroprevalence is around 80% and has remained stable for the past 4 decades. Approximately 3,500 bears are hunted yearly in Pennsylvania alone. The validity of different serological tests is discussed based on bioassay and serological comparisons. Seroprevalence in grizzly bears (Ursus arctos) is lower than that in black bears. Even polar bears (Ursus maritimus) are infected; infections in these animals are ecologically interesting because of the absence of felids in the Arctic. Clinical toxoplasmosis in bears is rare and not documented in adult animals. The few reports of fatal toxoplasmosis in young bears need confirmation. Viable T. gondii has been isolated from black bears and a grizzly bear. The genetic diversity of isolates based on DNA from viable T. gondii isolates is discussed. Genetic typing of a total of 26 T. gondii samples from bears using 10 PCR-RFLP markers revealed 8 PCR-RFLP ToxoDB genotypes: #1 (clonal type II) in 3 samples, #2 (clonal type III) in 8 samples, #4 (haplogroup 12) in 3 samples, #5 (haplogroup 12) in 3 samples, #74 in 5 samples, #90 in 1 sample, #147 in 1 sample, and #216 in 2 samples. These results suggest relatively high genetic diversity of T. gondii in bears. Overall, T. gondii isolates in bears range from those circulating in a domestic cycle (genotypes #1 and #2) to those mainly associated with wildlife (such as genotypes #4 and #5, together known as haplogroup 12). A patient who acquired clinical Trichinella spiralis infection after eating undercooked bear meat also acquired T. gondii infection. Freezing of infected meat kills T. gondii, including the strains isolated from bears.
TL;DR: In this paper, the authors analyzed the antimalarial effects of marine natural products (kapakahine and kulolide-1) against P. falciparum.
Abstract: Malaria remains one of the most important infectious diseases in the world. In 2017 alone, approximately 219 million people were infected with malaria, and 435,000 people died of this disease. Plasmodium falciparum, which causes falciparum malaria, is becoming resistant to artemisinin (ART) in Southeast Asia; therefore, new antimalarial drugs are urgently needed. Some excellent antimalarial drugs, such as quinine and ART, were originally obtained from plants. Hence, we analyzed the antimalarial effects of marine natural products to find new antimalarial agents. We used a malaria growth inhibition assay to determine the antimalarial ability and half-maximal inhibitory concentration (IC50) values of the marine organism-derived compounds. Three compounds (kapakahine A, kapakahine B, and kulolide-1) showed antimalarial effects, and one (kapakahine F) showed selective antimalarial effects on the Dd2 clone. Although the IC50 values obtained for these compounds were greater than that of ART, their potency against P. falciparum is sufficient to warrant further investigation of these compounds as possible drug leads.
TL;DR: In this article, the authors document antibody responses, tissue cyst burden, and mouse virulence of T. gondii strains isolated from different hosts in China and positively correlate with the T.gondii antibody titer (R2 = 0.3345).
Abstract: Toxoplasma gondii is an obligate intracellular parasite that has a worldwide distribution and can infect almost all warm-blood animals. Serological tests are the main detection methods for T. gondii infection in animals and humans. Little is known of biological behavior, antibody responses, and virulence of T. gondii strains in mice from China. Here we document antibody responses, tissue cyst burden, and mouse virulence of T. gondii strains isolated from different hosts in China. All T. gondii strains formed tissue cysts in the brains of mice and positively correlated with the T. gondii antibody titer (R2 = 0.3345). These results should aid in the diagnosis and characterization of T. gondii isolates.
TL;DR: A new archiacanthocephalan in the family Gigantorhynchidae, Intraproboscis sanghae n. gen., n. sp. is described from females collected from the African black-bellied pangolin Phataginus tetradactyla Linn as mentioned in this paper.
Abstract: A new archiacanthocephalan in the family Gigantorhynchidae, Intraproboscis sanghae n. gen., n. sp. is described from females collected from the African black-bellied pangolin Phataginus tetradactyla Linn. (Manidae) in the Central African Republic. A dichotomous key to the genera of Gigantorhynchidae is provided. The specimens presented are distinct from those of the genus Gigantorhynchus Hamann, 1892 that have only 1 or 2 circles of hooks (crowns) at the apical end of the proboscis and are found in South American mammals, except for Gigantorhynchus pesteri Tadros, 1966 from baboons in Rhodesia (Zimbabwe), Africa (Amin, 2013). They superficially resemble those of the other gigantorhynchid genus Mediorhynchus Van Cleave, 1916, especially in the organization of the truncate-cone proboscis and the position of the receptacle. Species of Mediorhynchus are bird parasites. The new genus, Intraproboscis, now the third genus in Gigantorhynchidae; however, is distinguished from Mediorhynchus by having a simple proboscis receptacle that is completely suspended within the proboscis, the passage of the retractor muscles through the receptacle into the body cavity posteriorly, absence of neck, and presence of a parareceptacle structure (first finding in the Archiacanthocephala) and a uterine vesicle; among other features, including the differential dorsoventral thickness of the body wall. The receptacle in Mediorhynchus is complex, with many accessory muscles and retractor muscles passing into the body cavity dorsally and ventrally. Our specimens reached 180 mm in length and the proboscis had 34-36 rows of 6-7 ventrally lamellated, rooted hooks each anteriorly, and 15-17 spinelike hooks each posteriorly. Micropores extended into the anterior and posterior proboscis and energy dispersive x-ray analysis (EDXA) of anterior hooks showed high levels of calcium and phosphorus but negligible traces of sulfur. Spinelike hooks in the posterior proboscis had lower levels of Ca and P and slightly higher levels of S. Molecular and phylogenetic analyses based on the 18S rDNA gene placed I. sanghae in a clade with the archiacanthocephalans Mediorhynchus, Moniliformis, Macracanthorhynchus, Oncicola, and Oligacanthorhynchus.
TL;DR: The dauer hypothesis as discussed by the authors proposes that free-living nematode lineages evolved into parasites through two intermediate steps, phoresy and necromeny, and that non-parasitic species that approximate those intermediate steps can be used to uncover the timing and original function of parasitic traits.
Abstract: Parasitic lineages have acquired suites of new traits compared to their nearest free-living relatives. When and why did these traits arise? We can envision lineages evolving through multiple stable intermediate steps such as a series of increasingly exploitative species interactions. This view allows us to use non-parasitic species that approximate those intermediate steps to uncover the timing and original function of parasitic traits, knowledge critical to understanding the evolution of parasitism. The dauer hypothesis proposes that free-living nematode lineages evolved into parasites through two intermediate steps, phoresy and necromeny. Here we delve into the proposed steps of the dauer hypothesis by collecting and organizing data from genetic, behavioral, and ecological studies in a range of nematode species. We argue that hypotheses on the evolution of parasites will be strengthened by complementing comparative genomic studies with ecological studies on non-parasites that approximate intermediate steps.
TL;DR: In this paper, infection pressure is suggested to be a strong driver of transmission within ecosystems, and the authors tested if infection pressure drives seroprevalence in intermediate host species for Toxoplasma gondii.
Abstract: Parasite infection pressure is suggested to be a strong driver of transmission within ecosystems. We tested if infection pressure drives seroprevalence in intermediate host species for Toxoplasma gondii. We defined Toxoplasma infection pressure to intermediate host species as the combined influence of cat abundance, environmental conditions, and its prevalence in the cat population. We sampled and tested 2 species of rodent and collated information on Toxoplasma seroprevalence in koalas, wallabies, kangaroos, and sheep. All species were sampled using equivalent methods, within a 2-yr period, and from adjacent regions of low and high Toxoplasma infection pressure. The seroprevalence of Toxoplasma in kangaroos scaled with infection pressure, but we observed no statistical difference in seroprevalence for any other species between these 2 regions. Within the region of low infection pressure, Toxoplasma seroprevalence did not differ between species. However, within the region of high Toxoplasma infection pressure, we observed large variation in seroprevalence between species. Our results demonstrate that infection pressure is not sufficient by itself, but merely necessary, to drive Toxoplasma seroprevalence in intermediate host species. Where Toxoplasma seroprevalence in an intermediate host species is already low, further reducing infection pressure will not necessarily further decrease seroprevalence in those species. This has important ramifications for the mitigation of parasite infections and suggests that reductions in Toxoplasma infection pressure, intended to reduce infections, may be most effective and applicable to species that are known to experience high rates of infection.
TL;DR: In this paper, the authors document novel parasites that inhabited the scaled quail, Callipepla squamata, of the Trans-Pecos ecoregion of Texas.
Abstract: Quail populations in the United States have been declining for several decades, and the role that parasites may be playing in this decline is not well understood. The goal of this study was to document novel parasites that inhabited the scaled quail, Callipepla squamata, of the Trans-Pecos ecoregion of Texas. To do this, quail were collected by hunter-harvest, night-netting, and funnel-trapping and were necropsied in the laboratory to determine the parasites they hosted. After analyzing 386 birds, we identified Dispharynx sp. in one of the samples. This specimen is the first to be officially documented in scaled quail.