Potential Intermediate Hosts Research Articles

Molecular identification of potential intermediate hosts of Aulonocephalus pennula from the order Orthoptera.

Aulonocephalus pennula is a heteroxenous nematode that commonly infects a declining game bird, the northern bobwhite quail (Colinus virginianus). There is a lack of information on the life cycle of A. pennula and the potential effects of infection on bobwhites. In order to better understand the life cycle of this parasite, various species from the order Orthoptera were collected from a field site in Mitchell County, Texas. Using polymerase chain reaction (PCR), nine potential intermediate hosts were identified from the 35 orthopteran species collected. Later, ten live specimens were collected to identify larvae within the potential intermediate hosts. Larvae were present in three of these and were sent for sequencing. Similarly, the presence of larvae was confirmed from extra tissues of samples identified as positive with PCR. This was the first study to document potential intermediate hosts, but future studies are needed to confirm that these species are capable of transmitting infection to bobwhite. However, this study demonstrates that PCR has increased sensitivity and may be a valuable tool when determining intermediate hosts.

Insights into the role of turkeys as potential intermediate host for influenza viruses

Avian influenza viruses have become endemic in land-based domestic poultry and have crossed species barriers. Turkeys are an important host in influenza virus ecology because they are susceptible to infection with these viruses and are often involved in inter species transmission. Several previous studies reveal that waterfowl-origin influenza viruses can be more easily transmitted to domestic turkeys than to chickens. Studies indicate turkeys to be better hosts for low pathogenic avian influenza viruses isolated from commercial poultry operations and live bird markets in comparison to chickens. Moreover, turkeys require low, 50% infectious-dose titres from wild bird as well as poultry adapted viruses, suggesting their high susceptibility for infection following a low dose exposure. Additionally, interspecies transmission of swine influenza viruses to turkeys occurs frequently, thus turkeys may be considered as a bridge species between poultry and wildlife. These findings suggest that turkeys can be easily infected with influenza viruses of different origins and highlight the potential role of turkeys in the transmission and maintenance of influenza viruses between premises.

Molecular detection of Oxyspirura larvae in arthropod intermediate hosts

To determine potential intermediate hosts of Oxyspirura petrowi, a common nematode eyeworm of wild gallinaceous birds, various arthropod species including red harvester ants, beetles, wood cockroaches, crickets, grasshoppers, katydids, and desert termites were screened for the presence of O. petrowi using specific polymerase chain reaction (PCR) primers targeting the internal transcribed spacer 2 region (ITS2) of the eyeworm ribosomal deoxyribonucleic acid (rDNA). This is the first study to investigate the intermediate hosts of O. petrowi utilizing molecular techniques. We determined 38% (13/34) of the cockroaches, 27% (3/11) of the crickets, and 23% (68/289) of the grasshoppers which were positive for O. petrowi. Identifying potential intermediate hosts of O. petrowi is essential to better understanding the epizoology of the eyeworm’s transmission mechanics and to controlling infections in wild gallinaceous birds.

Larval development of Aelurostrongylus abstrusus in experimentally infected Rumina decollata snails

Aelurostrongylus abstrusus is a lungworm distributed worldwide that affects wild and domestic cats, causing bronchopneumonia of varying intensity. Snails serve as intermediate hosts. The aim of the present study was to assess the larval development of A. abstrusus in R. decollata snails and to investigate its potential as an intermediate host. For this purpose, first-stage larvae (L1) of A. abstrusus were obtained from the faeces of naturally infected cats. Doses of 500 L1/snail were given to 24 R. decollata snails, placed on the soil of the breeder chamber, and maintained under laboratory conditions. Three snails were killed at 8, 10, 12, 16, 22, 26, 45 and 55 days post-infection (dpi), and the muscular foot and visceral body were separately digested by an artificial digestion technique. The morphometric parameters of different larval stages were recorded. The mean number of larvae reaching the infective stage at the end of the study (L3) was 262 larvae/snail. The greatest development to L3 was recorded from days16 to 55 pi, during which the isolation was maximum. A. Abstrusus L3 were isolated from the viscera, but isolation from the snail foot was significantly higher. Our results showed for the first time the ability of A. Abstrusus larvae to develop in R. decollata, thus serving as a potential intermediate host.

Microtus arvalis and Arvicola scherman: Key Players in the Echinococcus multilocularis Life Cycle.

A broad range of rodent species are described as potential intermediate hosts for Echinococcus multilocularis, a wide-spread zoonotic cestode causing alveolar echinococcosis. However, little is known about the relative contribution of these species for parasite reproduction and the maintenance of its life cycle. In a comparative study in a high endemic region in Zurich, Switzerland, we investigated prevalence rates and fertility of E. multilocularis in the most abundant vole species as well as the predation rate of foxes on these species. To ensure that the fox families had access to different vole species and that these voles were exposed to the same environmental contamination with parasite eggs, we selected eight study plots where at least two rodent species co-occurred. The parasite prevalence in Microtus arvalis [11.0%, confidence intervals (CI) 8.9–13.4] was significantly higher than in Arvicola scherman (5.3%, 3.9–7.1) and Myodes glareolus (3.9%, 2.0–6.7). None of the, only 29 individuals of, Microtus agrestis was infected (0%, 0.0–9.8) and the species was excluded for further analyses. Logistic regression models for the prevalences revealed significant differences between nearby study plots and higher infection rates for females, heavier individuals, and individuals trapped during spring, when the prevalence in M. arvalis peaked up to 65% (CI 50–79) in one plot. Furthermore, we detected significantly higher percentages of fertile infections in M. arvalis and M. glareolus than in A. scherman (OR 11.2 and 6.4, respectively) and a significantly higher protoscolex number in M. glareolus (median 100,000) than in M. arvalis (13,500) and A. scherman (4,290). The most abundant fox prey remains were of the genera Microtus (12.3%, CI 8.4–17.2) and Arvicola (11.5%, 7.7–16.3), whereas Myodes was never recorded as prey (0.0–1.3%). We conclude that M. arvalis and to a lesser extent A. scherman can be regarded as key intermediate hosts in Western and Central European high-endemic regions whereas M. glareolus and M. agrestis play a marginal role. We, therefore, postulate that distribution models of these species could contribute to predict parasite occurrence on a more detailed spatial scale than models of the distribution of foxes which have a very broad and uniform distribution.

Detection and full genome characterization of two beta CoV viruses related to Middle East respiratory syndrome from bats in Italy

BackgroundMiddle East respiratory syndrome coronavirus (MERS-CoV), which belongs to beta group of coronavirus, can infect multiple host species and causes severe diseases in humans. Multiple surveillance and phylogenetic studies suggest a bat origin. In this study, we describe the detection and full genome characterization of two CoVs closely related to MERS-CoV from two Italian bats, Pipistrellus kuhlii and Hypsugo savii.MethodsPool of viscera were tested by a pan-coronavirus RT-PCR. Virus isolation was attempted by inoculation in different cell lines. Full genome sequencing was performed using the Ion Torrent platform and phylogenetic trees were performed using IQtree software. Similarity plots of CoV clade c genomes were generated by using SSE v1.2. The three dimensional macromolecular structure (3DMMS) of the receptor binding domain (RBD) in the S protein was predicted by sequence-homology method using the protein data bank (PDB).ResultsBoth samples resulted positive to the pan-coronavirus RT-PCR (IT-batCoVs) and their genome organization showed identical pattern of MERS CoV. Phylogenetic analysis showed a monophyletic group placed in the Beta2c clade formed by MERS-CoV sequences originating from humans and camels and bat-related sequences from Africa, Italy and China. The comparison of the secondary and 3DMMS of the RBD of IT-batCoVs with MERS, HKU4 and HKU5 bat sequences showed two aa deletions located in a region corresponding to the external subdomain of MERS-RBD in IT-batCoV and HKU5 RBDs.ConclusionsThis study reported two beta CoVs closely related to MERS that were obtained from two bats belonging to two commonly recorded species in Italy (P. kuhlii and H. savii). The analysis of the RBD showed similar structure in IT-batCoVs and HKU5 respect to HKU4 sequences. Since the RBD domain of HKU4 but not HKU5 can bind to the human DPP4 receptor for MERS-CoV, it is possible to suggest also for IT-batCoVs the absence of DPP4-binding potential. More surveillance studies are needed to better investigate the potential intermediate hosts that may play a role in the interspecies transmission of known and currently unknown coronaviruses with particular attention to the S protein and the receptor specificity and binding affinity.

Meerkats (Suricata suricatta), a new definitive host of the canid nematode Angiostrongylus vasorum.

Angiostronglyus vasorum is a cardiopulmonary nematode infecting mainly canids such as dogs (Canis familiaris) and foxes (Vulpes vulpes). Natural infections have also been reported in mustelids and red pandas (Ailurus fulgens fulgens). We report the occurrence of natural A. vasorum infections in a group of captive meerkats (Suricata suricatta), housed at a university facility in Switzerland. A. vasorum first-stage larvae (L1) were initially identified in a pooled faecal sample. Individual samples, investigated with the Baermann-Wetzel technique, revealed that 41% (7/17) of the meerkats were infected, with ranges of 2–125 L1/g faeces. PCR and sequencing of part of the ITS-2 region resulted in 100% identity with A. vasorum. Infected animals did not show clinical signs. One meerkat died two days after diagnosis. Upon necropsy one adult specimen was recovered; histological examination of the lung revealed granulomatous pneumonia caused by A. vasorum larvae and eggs as well as intima and media hyperplasia and isolated arteriosclerosis of larger lung vessels. However, the cause of death was a spleen rupture with associated blood loss. All meerkats were topically treated with 10 mg imidacloprid/2.5 mg moxidectin per animal, after which they became negative in all follow up faecal examinations. Potential intermediate (gastropods) and paratenic hosts (birds) were collected from within or outside the meerkats enclosure. Gastropods were examined by PCR and bird samples by digestion. Four out of 193 (2.1%) gastropod samples were positive for A. vasorum, whereas none of the bird samples were positive. Meerkats, belonging to the Herpestidae, therefore are suitable definitive hosts for A. vasorum, with production and excretion of live L1. Meerkats kept in captivity in areas where A. vasorum is endemic and with potential contact to intermediate hosts are at risk of infection. Regular faecal examinations including Baermann-Wetzel technique should be considered.

Mapping freshwater snails in north-western Angola: distribution, identity and molecular diversity of medically important taxa

BackgroundThis study was designed to determine the distribution and identity of potential intermediate snail hosts of Schistosoma spp. in Bengo, Luanda, Kwanza Norte and Malanje Provinces in north-western Angola. This is an area where infection with Schistosoma haematobium, causing urogenital schistosomiasis, is common but little is yet known about transmission of the disease. Angola has had a varied past with regard to disease control and is revitalising efforts to combat neglected tropical diseases.MethodsSnails were sampled from 60 water-contact points. Specimens of the genera Bulinus, Biomphalaria or Lymnaea were screened for trematode infections by inducing cercarial shedding. Snails were initially identified using shell morphology; subsequently a cytochrome c oxidase subunit 1 (cox1) gene fragment was amplified from a subset of snails from each site, for molecular identification. Cercariae were captured onto FTA cards for molecular analysis. Specimens of Bulinus angolensis collected from the original locality of the type specimen have been characterised and comparisons made with snails collected in 1957 held at the Natural History Museum, London, UK.ResultsIn total snails of nine genera were identified using morphological characteristics: Biomphalaria, Bulinus, Gyraulus, Lanistes, Lentorbis, Lymnaea, Melanoides, Physa and Succinea. Significant for schistosomiasis transmission, was the discovery of Bulinus globosus, B. canescens, B. angolensis, B. crystallinus and Biomphalaria salinarum in their type-localities and elsewhere. Bulinus globosus and B. angolensis occurred in two distinct geographical areas. The cox1 sequence for B. globosus differed markedly from those from specimens of this species collected from other countries. Bulinus angolensis is more closely related to B. globosus than originally documented and should be included in the B. africanus group. Schistosoma haematobium cercariae were recovered from B. globosus from two locations: Cabungo, Bengo (20 snails) and Calandula, Malanje (5 snails). Schistosoma haematobium cercariae were identified as group 1 cox1 corresponding to the type common throughout the African mainland.ConclusionsVarious freshwater bodies in north-western Angola harbour potential intermediate snail hosts for urogenital schistosomiasis, highlighting the need to map the rest of the country to identify areas where transmission can occur and where control efforts should be targeted. The molecular phylogeny generated from the samples confirmed that considerable variation exists in B. globosus, which is the primary snail host for S. haematobium in many regions of Africa.

Occurrence and effect of trematode metacercariae in two endangered killifishes from Greece

We report digeneans (Diplostomidae, Crassiphialinae) in the endangered freshwater fishes Valencia letourneuxi and Valencia robertae, endemics of Western Greece. Digenean metacercariae occurred in two forms in the abdominal cavity, excysted and encysted, the latter attached to the gonads, liver and alimentary tract. Parasites were, using morphological and molecular techniques, identified as two representatives of Crassiphialinae, specifically part of the Posthodiplostomum-Ornithodiplostomum clade. The spatial, seasonal, and age class variation in parasite prevalence was examined. Autumn parasite prevalence varied between the six populations sampled (18.2 to 100%). Seasonal prevalence at the two sites sampled quadannually peaked in autumn and reached its lowest value in spring; prevalence increased with size to 100% in young adult fish. We did not find a correlation between prevalence and host sex. Overall parasites' weight averaged 0.64% of the host's, while parasite weight increased with host weight. A comparison of relative condition and hepatosomatic and gonadosomatic indices of infected and metacercariae-free specimens showed that infection did not have a significant effect on host body condition and reproduction. Regarding the parasite's life cycle, planorbid gastropods are proposed as potential first intermediate hosts in view of the host's diet and occurrence data of molluscs in the ecosystem. This is the first record of a diplostomid digenean in valenciid fishes and of representatives of the Posthodiplostomum-Ornithodiplostomum clade in a native Greek freshwater fish. Our findings are discussed in conjunction to fish conservation interventions, since parasites may contribute to the decline of endangered species.

Occurrence of tongue worm, Linguatula cf. serrata (Pentastomida: Linguatulidae) in wild canids and livestock in south-eastern Australia.

Pentastomids are obligate zoonotic arthropod parasites utilising canids and vulpids as their definitive hosts and several herbivorous species as their intermediate hosts. Reported only 10 times in Australia over the last 150 years as incidental findings, adult Pentastomids referred to as Linguatula serrata have been encountered in nasal cavities of domestic and wild dogs, and foxes. Nymphs have been reported in cattle and rabbits. In the present study, a number of potential definitive hosts, including red foxes (Vulpes vulpes), wild dogs (Canis lupus dingo and C.l. dingo x C. familiaris) and feral cats (Felis catus), and intermediate hosts cattle (Bos taurus), sheep (Ovis aries), feral pigs (Sus scrofa), rabbits (Oryctolagus cuniculus), goats (Capra hircus) and a European hare (Lepus europaeus), from the highlands of south-eastern Australia were examined. Of the animals examined 67.6% of wild dogs (n = 37), 14.5% of red foxes (n = 55) and 4.3% of cattle (n = 164) were found to be infected with Pentastomids, herein identified as Linguatula cf. serrata. The common occurrence of the parasite in wild dogs and less frequently in foxes suggests these wild canids have potential to act as a reservoir for infection of livestock, wildlife, domestic dogs and possibly humans. The unexpected high frequency of the parasite in wild dogs and foxes in south-eastern Australia suggests the parasite is more common than previously realised. Of the potential intermediate hosts in the region, only 4.3% of cattle were found to be infected with pentastomid nymphs which suggest the search for the host(s) acting as the main intermediate host in the region should continue. Future studies should investigate transmission patterns, health impacts on hosts and whether the parasite has zoonotic significance in Australia.

Small sarcocysts can be a feature of experimental infections with Sarcocystis neurona merozoites

Several reports indicate the presence of small tissue cysts associated with Sarcocystis neurona infections. Several failed attempts to develop tissue cysts in potential intermediate host using in vitro derived parasites originally isolated from horses with equine protozoal myeloencephalitis suggest that the experimental methods to achieve bradyzoites with those isolates was not possible. Those prior studies reported the lack of detectable sarcocysts based on histology and in vivo feeding trials. A recent report of successful production and detection of small sarcocysts triggered us to review archived tissues from earlier experimental infection studies. The retrospective review sought to determine if small sized sarcocysts were not detected due to their relatively smaller size and infrequency as compared to larger sized sarcocysts produced with other isolates in these experimental inoculation trials. Tissues from two prior in vivo inoculation studies, involving in vitro-produced parasites inoculated into laboratory-reared cats and raccoons, were re-examined by immunohistochemistry staining to more easily detect the tissue cysts. In the experimental cat study no small tissue cysts were seen, consistent with the original publication results. However, in the experimental raccoon study, one raccoon inoculated with an EPM-derived isolate, SN-UCD1, had small sarcocysts not reported in the original publication. This retrospective study suggests that much closer scrutiny of tissues, including the use of immunohistochemistry on tissue sections is required to detect the smaller S. neurona sarcocysts associated with the experimental inoculations of the isolates originally derived from horses with EPM.

Larval development of Angiostrongylus chabaudi, the causative agent of feline angiostrongylosis, in the snail Cornu aspersum.

Nematodes of the Angiostrongylidae family, such as Angiostrongylus vasorum and Angiostrongylus cantonensis, may cause potentially life-threatening diseases in several mammal species. Alongside these well-known species, Angiostrongylus chabaudi has been recently found affecting the cardiopulmonary system of domestic and wild cats from Italy, Germany, Greece, Romania and Bulgaria. Nonetheless, significant gaps in the understanding of A. chabaudi epidemiology include the lack of information of species acting as intermediate host and of the morphological description of larval stages. Cornu aspersum (n = 30) land snails were infected with 100 first-stage larvae of A. chabaudi collected from a naturally infected wildcat in Romania. Larvae at different developmental stages were found in 29 out of 30 (96·7%) infected snails and a total of 282 (mean 9·8 ± 3·02 larvae per each specimen) were collected from the gastropods. Here we demonstrate that A. chabaudi develops in snails and report C. aspersum as potential intermediate host for this parasitic nematode. Findings of this study are central to understand the ecological features of feline angiostrongylosis and its epidemiology within paratenic and intermediate hosts.

Seasonal variation of gastro-intestinal helminths of three bat species in the dry forest of western Mexico

Studies on helminths of chiropterans are relatively uncommon compared to those of other animals, and seasonal changes in helminth load have been rarely examined. We characterized the gastro-intestinal helminth load of 3 bats species to test for the existence of seasonal changes in response to known seasonal environmental and bat prey fluctuations. We did not find seasonal variation in most of the cases. However, the prevalence of 4 endoparasite species was significantly higher during one of the seasons. The highest richness was registered in Pteronotus parnellii during the wet season. The effective number of species was higher during the dry season in the 3 species of Pteronotus. Diet seems to be an important driver of helminth infracommunity structure, but we found heterogeneous patterns in the relationship between diversity and load of helminths and seasonal patterns of bat's diets and abundance of potential intermediate hosts.

Prevalence and seasonal transmission of Schistosoma haematobium infection among school-aged children in Kaedi town, southern Mauritania

BackgroundMauritania is at the fringe of transmission of human schistosomiasis, which mainly occurs in the southern and southeastern parts of the country. This study aimed to assess the influence of rainfall seasonality on the prevalence of Schistosoma haematobium infection among school-aged children in Kaedi, southern Mauritania.MethodsCross-sectional surveys (i.e. parasitological, malacological and observations on water-related human activities) were carried out in Kaedi between September 2014 and May 2015, during both the wet and dry seasons. A total of 2162 children aged 5–15 years provided a single urine sample that was subjected to S. haematobium diagnosis. Snails were sampled and checked for cercarial shedding. Water contact patterns of the local population were recorded by direct observation.ResultsThe prevalence of S. haematobium was 4.0% (86/2162, 95% confidence interval (CI): 3.2–4.9%) with a geometric mean egg count per 10 ml of urine of 3.7 (95% CI: 2.8–4.3). Being male (adjusted odds ratio (aOR) 1.78, 95% CI: 1.13–2.80), being at primary school (aOR 1.73, 95% CI: 1.04–2.87) and dry season (aOR 0.56, 95% CI: 0.35–0.89) were significantly associated with S. haematobium. Among 284 potential intermediate host snail specimens collected over the rainy and dry seasons, three species were identified: Bulinus senegalensis (n = 13) and B. forskalii (n = 161) in the rainy season, and B. truncatus (n = 157) in the wet season. No snail was shedding cercariae. On average, seven human water contacts were recorded per hour per observer over a 28-day observation period. Twelve types of water contact activities were identified among which, swimming/bathing was predominant (n = 3788, 36.9%), followed by washing clothes (n = 2016, 19.7%) and washing dishes (n = 1322, 12.9%). Females (n = 5270, 51.4%) were slightly more in contact with water than males (n = 4983, 48.6%). The average time spent in the water per person per day was 14.2 min (95% CI: 13.8–14.6 min). The frequency and duration of water contact followed a seasonal pattern.ConclusionOur findings demonstrate a low prevalence and intensity of S. haematobium among school-aged children in Kaedi. Appropriate integrated control measures, including health education among at-risk communities and snail control may help to interrupt transmission of S. haematobium in Kaedi.

If termite Coptotermes acinaciformis is not an intermediate host, could it be a safe food source for humans?

This study explores the possibility of Coptotermes acinaciformis being a commercial product for human consumption. We examined whether C. acinaciformis (Isoptera: Rhinotermitidae) is the intermediate host for the nematodes Abbreviata hastaspicula and Abbreviata antarctica by exposing a total of 13,500 C. acinaciformis to the infected faeces of Varanus gouldii (Squamata: Lacertilia: Varanidae) that contained embryonated eggs of the nematodes A. hastaspicula and A. antarctica. The termites were dissected at 6 intervals (1 day, 2 days, 3 days, 4-23 days, 25-38 days and 48-53 days). Eggs of the nematodes were recovered in the mid-guts of the termites during the first three intervals. There was no evidence that any eggs hatched within the termites. No eggs or larvae were found in the last three intervals. We conclude therefore that C. acinaciformis is not a potential intermediate host for either species of Abbreviata. We recommend C. acinaciformis to be consumed as a food source if C. acinaciformis has no other microorganism that would cause disease to human.

The South-American distribution and southernmost record of Biomphalaria peregrina-a potential intermediate host of schistosomiasis.

Schistosomiasis remains a major parasitic disease, endemic in large parts of South America. Five neotropical species of Biomphalaria have been found to act as intermediate hosts of Schistosoma mansoni in natural populations, while others have been shown to be susceptible in experimental infections, although not found infected in the field. Among these potential intermediate hosts, Biomphalaria peregrina represents the most widespread species in South America, with confirmed occurrence records from Venezuela to northern Patagonia. In this study, we report the southernmost record for the species at the Pinturas River, in southern Patagonia, which finding implies a southward reassessment of the limit for the known species of this genus. The identities of the individuals from this population were confirmed through morphological examination, and by means of two mitochondrial genes, cytochrome oxidase subunit I (COI) and 16S-rRNA. With both markers, phylogenetic analyses were conducted in order to compare the genetic background of individuals from the Pinturas River with previously genetically characterized strains of B. peregrina from various South-American locations. In addition, we produced a potential distribution model of B. peregrina in South America and identified the environmental variables that best predict that distribution. The model was estimated through a maximum entropy algorithm and run with occurrence points obtained from several sources, including the scientific literature and international databases, along with climatic and hydrographic variables. Different phylogenetic analyses with either the COI or 16S-rRNA sequences did not conflict, but rather gave very similar topological organizations. Two major groups were identified, with sequences from the Pinturas River grouping together with haplotypes from subtropical and temperate regions. The model developed had a satisfactory performance for the study area. We observed that the areas with higher habitat suitability were found to be mainly linked to subtropical and temperate regions of South America between 15° and 45° south latitude, with different moderate- and low-suitability areas outside this range. We also identified the coldest temperatures as the main predictors of the potential distribution of this snail. Susceptibility surveys would be required to evaluate if southern populations of B. peregrina still retain their potential as intermediate hosts of S. mansoni.

Geographic distribution of Angiostrongylus cantonensis in wild rats (Rattus rattus) and terrestrial snails in Florida, USA

The parasitic nematode Angiostrongylus cantonensis is a major cause of eosinophilic meningitis in humans, and has been documented in other incidental hosts such as birds, horses, dogs and non-human primates. It is endemic in Hawaii, and there have been sporadic reports in the southern continental United States. This parasite uses rats as definitive hosts and snails as intermediate hosts. In this study, we collected potential definitive and intermediate hosts throughout Florida to ascertain the geographic distribution in the state: Rats, environmental rat fecal samples, and snails were collected from 18 counties throughout the state. Classical diagnostics and morphological identification, along with molecular techniques were used to identify nematode species and confirm the presence of A. cantonensis.Of the 171 Rattus rattus collected, 39 (22.8%) were positive for A. cantonensis, and 6 of the 37 (16.2%) environmental rat fecal samples collected in three of the surveyed counties were also positive for this parasite by real time PCR. We examined 1,437 gastropods, which represented 32 species; 27 (1.9%) were positive for A. cantonensis from multiple sites across Florida. Three non-native gastropod species, Bradybaena similaris, Zachrysia provisoria, and Paropeas achatinaceum, and three native gastropod species, Succinea floridana, Ventridens demissus, and Zonitoides arboreus, which are newly recorded intermediate hosts for the parasite, were positive for A. cantonensis. This study indicates that A. cantonensis is established in Florida through the finding of adult and larval stages in definitive and intermediate hosts, respectively, throughout the state. The ability for this historically subtropical nematode to thrive in a more temperate climate is alarming, however as the climate changes and average temperatures rise, gastropod distributions will probably expand, leading to the spread of this parasite in more temperate areas. Through greater awareness of host species and prevalence of A. cantonensis in the United States, potential accidental infections may be avoided.

Dynamics of freshwater snails and Schistosoma infection prevalence in schoolchildren during the construction and operation of a multipurpose dam in central C\xf4te d\u2019Ivoire

BackgroundThe construction and operation of small multipurpose dams in Africa have a history of altering the transmission of water-based diseases, including schistosomiasis. The current study was designed to investigate the abundance and dynamics of schistosomiasis intermediate host snails and Schistosoma infections in humans during the construction and the first years of operation of a small multipurpose dam in Côte d’Ivoire.MethodsThe study was carried out in Raffierkro and four neighbouring villages in central Côte d’Ivoire between 2007 and 2012. Snails were collected by two experienced investigators using scoops and forceps for 15 min at each site. Snails were identified at genera and, whenever possible, species level, and subjected to testing for cercarial shedding. Schoolchildren aged 6–15 years were examined once every year for Schistosoma haematobium and S. mansoni infection, using urine filtration and duplication Kato-Katz thick smears, respectively. Additionally, 551 adults were examined for Schistosoma infection before (June 2007) and 359 individuals 2 years after dam construction (June 2009).ResultsOverall, 1 700 snails belonging to nine different genera were collected from 19 sampling sites. Bulinus (potential intermediate host snails of S. haematobium) and Pila were the most common genera, whereas Biomphalaria (potential intermediate host snail of S. mansoni), Lymnaea, Physa and Melanoides were found in two villages. During the first-year sampling period, 65 snails were collected, of which 13 (20%) were schistosomiasis intermediate hosts. In subsequent years, out of 1 635 snails collected, 1 079 (66%) were identified as potential intermediate host for schistosomiasis, but none were shedding cercariae. The prevalence of S. mansoni among adults in the study area was low (0.4% in 2007 and 0.3% in 2009), whereas the prevalence of S. haematobium declined from 13.9% to 2.9% in this two-year period.ConclusionsThe low prevalence of schistosomiasis in humans and the absence of infected intermediate host snails during the construction and early phase of operation of a small multipurpose dam suggest that there was no or only very little local transmission. However, the considerable increase in the number of intermediate host snails and their dispersion in irrigation canals call for rigorous surveillance, so that adequate public health measures can be taken in case of early signs of an outbreak.

Gaining insights into the ecological role of the New Zealand sole (Peltorhamphus novaezeelandiae) through parasites.

Despite the fact that tapeworms comprise the bulk of parasite communities of sharks in marine ecosystems, little is known about their life cycles and, more specifically, about the potential intermediate hosts they utilize as transmission routes. In the absence of morphological features required for specific identification of larval tapeworms from potential intermediate hosts, recent molecular advances have contributed to linking larval and adult parasites and, in some instances, uncovering unknown trophic links. Host-parasite checklists are often the first source of information consulted to assess the diversity and host specificity of parasites, and provide insights into parasite identification. However, these host-parasite checklists are only useful if they encompass the full spectrum of associations between hosts and parasites. A checklist of New Zealand fishes and their parasites has been published, but recent parasitological examinations of commercial fish species reveal that the checklist appears to be far from complete. We focused our current study on a comprehensive survey of macroparasites of a commercial species, the New Zealand sole (Peltorhamphus novaezeelandiae) off the coast of Otago, New Zealand. Specifically, we were expecting to recover marine tapeworms using sharks as their definitive hosts that are generally underreported in parasite surveys. The parasites recovered included tapeworms, flukes, round worms and thorny-headed worms. Surprisingly, a large proportion of the non-tapeworm parasites we recovered were not previously reported from this fish species. A discussion on the potential ecological roles played by this fish species in the transmission of parasites is included.

Assessing the prevalence of urogenital schistosomaisis and transmission risk factors amongst school-aged children around Map\xe9 dam ecological suburbs in Malantouen district, Cameroon

BackgroundUrogenital schistosomiasis is a parasitic infection of public health importance that affects over 112 million people worldwide. The study aimed at assessing the urogenital schistosomiasis prevalence and risk factors of transmission around Mape dam suburds in Malantouen district, West, Cameroon.MethodsThe study was conducted using semi-structured pretested questionnaires to collect socio-demographic and ecological data. Urine samples were also collected and used to confirm the prevalence of schistosomiasis in consented school-aged children in four primary schools between March – July 2014. Snails’ samples around the dam surburbs were also collected for taxonomy characterization and species identification. Data were compiled and quality control assessed and analysed using SPSS version 17 and Epiinfo data 3.1. P < 0.05 was considered statistical significance.ResultsQuestionnaires were administered to 229 pupils, with gender ratio of 1.04 (m/f). The prevalence of schistosomiasis haematobium was 16.6%. Mambonko school site, which is the closest to the dam suburbs, registered the greatest prevalence rate of 40%. The age group beween 10–13 years was the most infected (18.3%) and boys were more infested than girls (21.0% vs. 15.5%). Haematuria, urination pain, school absentiesm and poor performance were the major recorded complications in 39.5 and 26.3% males to female respectively. Infection rate gender disparity documented is still poorly understood and Bulinus truncatus collected from Mambonko suburb as potential snail intermediate host requires further studies.ConclusionsAuthors advocated that schools and dam suburds sustained and innovative community-based surveillance and response targeted interventions implementation are needed to inform and support decision-making policy, but also in improving effective contextual behavioural communication changes and MDA improved uptake measures on national schistosomiasis control and elimination in Cameroon.