Artemia is Capable of Spreading Oocysts of Cryptosporidium and the Cysts of Giardia

Comparison of Chemical and Biological Methods of Filtering Cryptosporidia from Water

Despite the fact that Cryptosporidium spp. is a parasite which commonly causes diarrhea, it still receives little attention. In our experiment, we focused on comparing the biological (N. davidi shrimp) and physical (zeolite with different thicknesses) possibility of filtering cryptosporidia from a small volume of water, which could contribute to increasing the catchability of this parasite. We monitored the ability to capture oocysts of the parasite Cryptosporidium parvum, genotype IIaA11G2R1, found in water samples. We infected drinking water with feces with a known number of cryptosporidial oocysts. One gram of sample contained ±28 oocysts. We filtered eight water samples with different concentrations of oocysts (0.1-2 g of infected stool per 15 L of water) using zeolite with a particle thickness of 0.2-0.6 mm and 0-0.3 mm. This was followed by purification, centrifugation and isolation utilizing the isolation kit AmpliSens^® DNA-sorb-B, which is intended for stool. In total, 120 shrimp were divided into four aquariums (A, B, C, n = 30) including the control (K), while drinking water with the same parameters was infected with different concentrations of oocysts (A: 2.5 g, B: 2 g, C: 1 g of infected stool per 15 L of water). We took 10 individual shrimp and processed them in three time intervals (6 h, 12 h and 24 h). We processed them whole, and we isolated the DNA utilizing the isolation kit AmpliSens^® DNA-sorb-AM, which is intended for tissues. Detection was carried out by molecular methods, namely the Nested PCR targeting of the region of the GP60 gene (60 kD glycoprotein). Gel electrophoresis showed the presence of C. parvum in seven zeolite-filtered water samples, and the parasite was not found in the water sample with the lowest number of oocysts filtered through the smaller-particle zeolite. There were 67 C. parvum-positive shrimp. Whereas the most positive shrimp were identified at 12 h of sampling, the least were identified at the 24 h mark. No shrimp positive for C. parvum was found in the control group. By sequencing, we confirmed the presence of C. parvum, genotype IIaA11G2R1, in all positive samples. We thus proved that the filtration capabilities of zeolite and N. davidi can be used for the rapid diagnosis of the presence of protozoa in a small amount of studied water.

The global social-economic dimension of biological invasions by plankton: Grossly underestimated costs but a rising concern for water quality benefits?

Planktonic invasive species cause adverse effects on aquatic biodiversity and ecosystem services. However, these impacts are often underestimated because of unresolved taxonomic issues and limited biogeographic knowledge. Thus, it is pivotal to start a rigorous quantification of impacts undertaken by planktonic invasive species on global economies. We used the InvaCost database, the most up-to-date database of economic cost estimates of biological invasions worldwide, to produce the first critical assessment of the economic dimension of biological invasions caused by planktonic taxa. We found that in period spanning from 1960 to 2021, the cumulative global cost of plankton invasions was US$ 5.8 billion for permanent plankton (holoplankton) of which viruses encompassed nearly 93%. Apart from viruses, we found more costs related to zooplankton (US$ 297 million) than to the other groups summed, including myco- (US$ 73 million), phyto- (43 million), and bacterioplankton (US$ 0.7 million). Strikingly, harmful and potentially toxic cyanobacteria and dinoflagellates are completely absent from the database. Furthermore, the data base showed a decrease in costs over time, which is probably an artifact as a sharp rise of novel planktonic alien species has gained international attention. Also, assessments of the costs of larval meroplanktonic stages of littoral and benthic invasive invertebrates are lacking whereas cumulative global cost of their adults stages is high up to US$ 98 billion billion and increasing. Considering the challenges and perspectives of increasing but unnoticed or neglected impacts by plankton invasions, the assessment of their ecological and economic impacts should be of high priority.

A review of the current status of Cryptosporidium in fish

Species of the genus Cryptosporidium (phylum Apicomplexa) infect the epithelium of the gastrointestinal tract of several vertebrate hosts, including humans and domestic and wild animals. In the past 20 years, several studies have focused on Cryptosporidium in fish. To date, a total of four piscine-host-specific species (Cryptosporidium molnari, Cryptosporidium huwi, Cryptosporidium bollandi and Cryptosporidium abrahamseni), nine piscine genotypes and more than 29 unnamed genotypes have been described in fish hosts. In addition, Cryptosporidium species and genotypes typical of other groups of vertebrates have also been identified. This review summarizes the history, biology, pathology and clinical manifestations, as well as the transmission, prevalence and molecular epidemiology of Cryptosporidium in wild, cultured and ornamental fish from both marine and freshwater environments. Finally, the potential role of piscine hosts as a reservoir of zoonotic Cryptosporidium species is also discussed.

Artemia spp., a Susceptible Host and Vector for Lymphocystis Disease Virus

Different developmental stages of Artemia spp. (metanauplii, juveniles and adults) were bath-challenged with two isolates of the Lymphocystis disease virus (LCDV), namely, LCDV SA25 (belonging to the species Lymphocystis disease virus 3) and ATCC VR-342 (an unclassified member of the genus Lymphocystivirus). Viral quantification and gene expression were analyzed by qPCR at different times post-inoculation (pi). In addition, infectious titres were determined at 8 dpi by integrated cell culture (ICC)-RT-PCR, an assay that detects viral mRNA in inoculated cell cultures. In LCDV-challenged Artemia, the viral load increased by 2–3 orders of magnitude (depending on developmental stage and viral isolate) during the first 8–12 dpi, with viral titres up to 2.3 × 10² Most Probable Number of Infectious Units (MPNIU)/mg. Viral transcripts were detected in the infected Artemia, relative expression values showed a similar temporal evolution in the different experimental groups. Moreover, gilthead seabream (Sparus aurata) fingerlings were challenged by feeding on LCDV-infected metanauplii. Although no Lymphocystis symptoms were observed in the fish, the number of viral DNA copies was significantly higher at the end of the experimental trial and major capsid protein (mcp) gene expression was consistently detected. The results obtained support that LCDV infects Artemia spp., establishing an asymptomatic productive infection at least under the experimental conditions tested, and that the infected metanauplii are a vector for LCDV transmission to gilthead seabream.

Giardia and Cryptosporidium in cetaceans on the European Atlantic coast

The occurrence of Giardia and Cryptosporidium was investigated in cetacean specimens stranded on the northwestern coast of Spain (European Atlantic coast) by analysis of 65 samples of large intestine from eight species. The parasites were identified by direct immunofluorescence antibody test (IFAT) and by PCR amplification of the β-giardin gene, the ITS1-5.8S-ITS2 region and the SSU-rDNA gene of Giardia and the SSU-rDNA gene of Cryptosporidium. Giardia and Cryptosporidium were detected in 7 (10.8 %) and 9 samples (13.8 %), respectively. In two samples, co-infection with both parasites was observed. Giardia duodenalis assemblages A, C, D and F, and Cryptosporidium parvum were identified. This is the first report of G. duodenalis in Balaenoptera acutorostrata, Kogia breviceps and Stenella coeruleoalba and also the first report of Cryptosporidium sp. in B. acutorostrata and of C. parvum in S. coeruleoalba and Tursiops truncatus. These results extend the known host range of these waterborne enteroparasites.

Detection and molecular characterization of Giardia and Cryptosporidium in common dolphins (Delphinus delphis) stranded along the Galician coast (Northwest Spain)

The ubiquitous protozoan parasites Giardia and Cryptosporidium have been detected from many species of captive and free-living wildlife, representing most mammalian orders. Twenty species of marine mammals have been reported to inhabit Galician waters and the region has one of the highest rates of stranding in Europe. Evidence from stranding, reported by-catches and sightings, suggests that the common dolphin (Delphinus delphis) is the most abundant cetacean on the Galician coast (Northwest Spain). The objective of this study was to detect and molecularly characterize isolates of Giardia and Cryptosporidium obtained from common dolphins stranded in this area. Between 2005 and 2012, sections of large intestine from 133 common dolphins stranded along the Galician coast were collected by the personnel of the Galician Stranding Network (Coordinadora para o Estudo dos Mamíferos Mariños, CEMMA). Using direct immunofluorescence antibody test (IFAT) and PCR amplification and sequencing of the SSU-rDNA, β-giardin genes and the ITS1-5.8S-ITS2 region, Giardia and Cryptosporidium were detected in 8 (6.0%) and 12 samples (9.0%), respectively. In two samples, co-infection by both parasites was observed. The molecular characterization revealed the presence of Giardia duodenalis assemblages A (genotypes A1 and A2) and B and Cryptosporidium parvum in these samples. This constitutes the first study in which the presence of Giardia and Cryptosporidium has been investigated in common dolphins on the European Atlantic coast, and it is also the first report of C. parvum in this host. Our findings indicate that these animals could act as reservoir of these waterborne parasites or could be victims of the contamination originated by anthropogenic activities.

Zoonotic potential of Giardia

Giardia duodenalis (syn. Giardia lamblia and Giardia intestinalis) is a common intestinal parasite of humans and mammals worldwide. Assessing the zoonotic transmission of the infection requires molecular characterization as there is considerable genetic variation within G. duodenalis. To date eight major genetic groups (assemblages) have been identified, two of which (A and B) are found in both humans and animals, whereas the remaining six (C to H) are host-specific and do not infect humans. Sequence-based surveys of single loci have identified a number of genetic variants (genotypes) within assemblages A and B in animal species, some of which may have zoonotic potential. Multi-locus typing data, however, has shown that in most cases, animals do not share identical multi-locus types with humans. Furthermore, interpretation of genotyping data is complicated by the presence of multiple alleles that generate "double peaks" in sequencing files from PCR products, and by the potential exchange of genetic material among isolates, which may account for the non-concordance in the assignment of isolates to specific assemblages. Therefore, a better understanding of the genetics of this parasite is required to allow the design of more sensitive and variable subtyping tools, that in turn may help unravel the complex epidemiology of this infection.

Comparative studies on sorting cells from Artemia sinica at different developmental stages for in vitro cell culture

Cell growth in primary cell culture of the brine shrimp (Artemia sinica) embryo at 12 and 20 h after rehydration at 25°C was examined comparatively in modified Leibovitz-15 medium. The cells from A. sinica embryo at 12 h after rehydration were dispersed, and the cells disseminated but did not attach to the surface of wells and multiply at 2 d of culture, and 12 d later, the cells were degenerated and dead. The best growth of the brine shrimp cells was obtained from the prenauplii of A. sinica at 20 h after dormant embryo rehydration. The fibroblast-like cells attached to the well surface and multiplied at 15 d after the primary culture was set up. Confluent monolayer was formed at 50 d. The prenauplii cells have been subcultured up to passage 3 and maintained for approximately 200 d. The reasons for cell growth potential at the different developmental stages of Artemia embryo were discussed.

Host and environmental risk factors associated with Cryptosporidium scophthalmi (Apicomplexa) infection in cultured turbot, Psetta maxima (L.) (Pisces, Teleostei)

An epidemiological cohort study of Cryptosporidium scophthalmi in cultured turbot Psetta maxima L. of Northwestern Spain was conducted along a four-year period. Four different ongrowing cohorts were monitored monthly from introduction into the ongrowing tanks (10-50 g) until reaching market size (400-1400 g). The association of host and environmental factors with five categories of parasite abundance was assessed using a multivariable regression framework. Epidemiological factors assessed here were water temperature, weight, length, month of collection, season, age, origin, condition factor, water filtration, and status to the myxozoan Enteromyxum scophthalmi infection. E. scophthalmi was included into the analysis because it targets the same organ than C. scophthalmi and it was prevalent in the studied population. The multivariable analysis demonstrated the statistically significant association between several factors and parasite abundance. C. scophthalmi abundance was associated (P<0.05) with age, condition factor, season, and status to E. scophthalmi infection. Young animals, with poor condition factor, during spring or summer, and not infected with the myxozoan were most likely to be highly infected by C. scophthalmi. Inclusion of these four variables significantly (P<0.05) improved the model, compared to the model that did not include any of these epidemiological factors. Increasing levels of C. scophthalmi abundance were associated (P<0.01) with higher severity of C. scophthalmi-compatible lesions. The frequency of distribution of C. scophthalmi abundance was clearly right-skewed and fitted a negative binomial distribution, whereas the intensity of infection fitted a Poisson distribution. The quantification of the variance-to-mean ratio stratified by age demonstrated overdispersion for 8-16 months old fish, although this bivariate association is likely affected by several other factors, as suggested by the results of the multivariable analysis. The negative relation between C. scophthalmi abundance and status to E. scophthalmi infection suggests differences in the transmission, onset, and course of both infections. The coarse filtration used in some cohorts did not significantly affect the levels of infection. C. scophthalmi was probably introduced into the ongrowing tanks mainly with carrier fish, though the involvement of infective oocysts from the water supply cannot be disregarded. Infection prevalence and mean intensity decreased with fish age and a seasonal distribution was found. Results presented here will help to understand the epidemiology of C. scophthalmi in turbot, to estimate the expected levels of infection associated with presence or absence of epidemiological factors, and to quantify the impact that the disease may have on susceptible turbot populations. The multivariable model used here is more powerful than the visual inspection of graphics for exploring associations in cooperative processes and can be easily extended to the assessment of epidemiological associations in other population and parasitic diseases.

Possible involvement of Artemia as live diet in the transmission of cryptosporidiosis in cultured fish

The viability of Cryptosporidium parvum oocysts ingested by Artemia franciscana metanauplii was evaluated using two fluorogenic vital dyes. There was no significant difference (p = 0.09) between the viability of oocysts maintained in saline (control) and those recovered from the digestive tract of the microcrustacean 24 h after ingestion (95 vs 90% viable oocysts). The results suggest that Artemia, used as a life food in fish larviculture, may act as a vehicle for transmission of piscine cryptosporidiosis caused by Cryptosporidium molnari and Cryptosporidium scophthalmi.

Acanthamoeba as a temporal vehicle of Cryptosporidium

The capacity of Acanthamoeba to predate Cryptosporidium oocysts was demonstrated. A maximum of six oocysts per Acanthamoeba trophozoite were detected, and a slow elimination of the internalized oocysts to the surrounding culture medium was observed. Free-living amoebae may act as carriers of Cryptosporidium oocysts and, thus, may play an important role in the transmission of cryptosporidiosis.