Nodular gill disease (NGD) is an emerging condition associated with amoeba trophozoites in freshwater salmonid farms. However, unambiguous identification of the pathogens still must be achieved. This study aimed to identify the amoeba species involved in periodic NGD outbreaks in two rainbow trout (Oncorhynchus mykiss) farms in Northeastern Italy. During four episodes (February-April 2023), 88 fish were euthanized, and their gills were evaluated by macroscopic, microscopic and histopathological examination. The macroscopic and microscopic severity of the lesions and the degree of amoebae infestation were scored and statistically evaluated. One gill arch from each animal was put on non-nutrient agar (NNA) Petri dishes for amoeba isolation, cultivation and subsequent identification with SSU rDNA sequencing. Histopathology confirmed moderate to severe lesions consistent with NGD and mild to moderate amoeba infestation. The presence of amoebae was significantly correlated with lesion severity. Light microscopy of cultured amoebae strains and SSU rDNA analysis revealed the presence of a previously characterized amoeba Naegleria sp. strain GERK and several new strains: two strains from Hartmannelidae, three vannelid amoebae from the genus Ripella and cercozoan amoeba Rosculus. Despite the uncertainty in NGD etiopathogenesis and amoebae pathogenic role, identifying known and new amoebae leans towards a possible multi-aetiological origin.
- Klíčová slova
- Oncorhynchus mykiss, Italy, SSU rDNA, amphizoic amoeba, nodular gill disease (NGD), rainbow trout,
- MeSH
- amébiáza * veterinární parazitologie MeSH
- Amoeba genetika izolace a purifikace klasifikace MeSH
- Amoebozoa genetika izolace a purifikace klasifikace fyziologie MeSH
- fylogeneze MeSH
- nemoci ryb * parazitologie epidemiologie MeSH
- Oncorhynchus mykiss * parazitologie MeSH
- vodní hospodářství MeSH
- žábry * parazitologie patologie MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- Geografické názvy
- Itálie MeSH
Vector-borne diseases cause over 700,000 deaths annually and represent 17% of all infectious illnesses worldwide. This public health menace highlights the importance of understanding how arthropod vectors, microbes and their mammalian hosts interact. Currently, an emphasis of the scientific enterprise is at the vector-host interface where human pathogens are acquired and transmitted. At this spatial junction, arthropod effector molecules are secreted, enabling microbial pathogenesis and disease. Extracellular vesicles manipulate signaling networks by carrying proteins, lipids, carbohydrates and regulatory nucleic acids. Therefore, they are well positioned to aid in cell-to-cell communication and mediate molecular interactions. This Review briefly discusses exosome and microvesicle biogenesis, their cargo, and the role that nanovesicles play during pathogen spread, host colonization and disease pathogenesis. We then focus on the role of extracellular vesicles in dictating microbial pathogenesis and host immunity during transmission of vector-borne pathogens.
- Klíčová slova
- Arthropod-borne disease, Cell communication, Extracellular vesicle, Immunomodulation, Microbial transmission,
- MeSH
- amébiáza parazitologie přenos MeSH
- členovci - vektory * mikrobiologie parazitologie MeSH
- Culicidae mikrobiologie parazitologie MeSH
- exozómy imunologie mikrobiologie parazitologie MeSH
- extracelulární vezikuly * imunologie mikrobiologie parazitologie MeSH
- filarióza parazitologie přenos MeSH
- Hemiptera mikrobiologie parazitologie MeSH
- imunomodulace MeSH
- infekce přenášené vektorem MeSH
- interakce hostitele a parazita imunologie fyziologie MeSH
- leishmanióza parazitologie přenos MeSH
- lidé MeSH
- malárie parazitologie přenos MeSH
- nemoci přenášené vektory * mikrobiologie parazitologie přenos MeSH
- Psychodidae mikrobiologie parazitologie MeSH
- trypanozomiáza parazitologie přenos MeSH
- virové nemoci mikrobiologie přenos MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- přehledy MeSH
- Research Support, N.I.H., Extramural MeSH
Acanthamoebae success as human pathogens is largely due to the highly resistant cysts which represent a crucial problem in treatment of Acanthamoeba infections. Hence, the study of cyst wall composition and encystment play an important role in finding new therapeutic strategies. For the first time, we detected high activity of cytoskeletal elements - microtubular networks and filamentous actin, in late phases of encystment. Cellulose fibrils - the main components of endocyst were demonstrated in inter-cystic space, and finally in the ectocyst, hereby proving the presence of cellulose in both layers of the cyst wall. We detected clustering of intramembranous particles (IMPs) and their density alterations in cytoplasmic membrane during encystment. We propose a hypothesis that in the phase of endocyst formation, the IMP clusters represent cellulose microfibril terminal complexes involved in cellulose synthesis that after cyst wall completion are reduced. Cyst wall impermeability, due largely to a complex polysaccharide (glycans, mainly cellulose) has been shown to be responsible for Acanthamoeba biocide resistance and cellulose biosynthesis pathway is suggested to be a potential target in treatment of Acanthamoeba infections. Disruption of this pathway would affect the synthesis of cyst wall and reduce considerably the resistance to chemotherapeutic agents.
- MeSH
- Acanthamoeba izolace a purifikace metabolismus ultrastruktura MeSH
- amébiáza parazitologie MeSH
- buněčná membrána metabolismus ultrastruktura MeSH
- buněčná stěna metabolismus ultrastruktura MeSH
- celulosa metabolismus MeSH
- cytoskelet metabolismus ultrastruktura MeSH
- elektronová mikroskopie MeSH
- konfokální mikroskopie MeSH
- lidé MeSH
- mikrotubuly metabolismus ultrastruktura MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- celulosa MeSH
Neoparamoeba perurans is the aetiological agent of amoebic gill disease (AGD) in salmonids, however multiple other amoeba species colonise the gills and their role in AGD is unknown. Taxonomic assessments of these accompanying amoebae on AGD-affected salmon have previously been based on gross morphology alone. The aim of the present study was to document the diversity of amoebae colonising the gills of AGD-affected farmed Atlantic salmon using a combination of morphological and sequence-based taxonomic methods. Amoebae were characterised morphologically via light microscopy and transmission electron microscopy, and by phylogenetic analyses based on the 18S rRNA gene and cytochrome oxidase subunit I (COI) gene. In addition to N. perurans, 11 other amoebozoans were isolated from the gills, and were classified within the genera Neoparamoeba, Paramoeba, Vexillifera, Pseudoparamoeba, Vannella and Nolandella. In some cases, such as Paramoeba eilhardi, this is the first time this species has been isolated from the gills of teleost fish. Furthermore, sequencing of both the 18S rRNA and COI gene revealed significant genetic variation within genera. We highlight that there is a far greater diversity of amoebae colonising AGD-affected gills than previously established.
- Klíčová slova
- AGD, Amoebozoa, Aquaculture, Atlantic salmon, Discosea, Tubulinea,
- MeSH
- amébiáza parazitologie veterinární MeSH
- Amoebozoa klasifikace genetika ultrastruktura MeSH
- biodiverzita * MeSH
- fylogeneze MeSH
- mikroskopie MeSH
- nemoci ryb parazitologie MeSH
- respirační komplex IV genetika MeSH
- RNA ribozomální 18S genetika MeSH
- Salmo salar parazitologie MeSH
- transmisní elektronová mikroskopie MeSH
- žábry parazitologie MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- respirační komplex IV MeSH
- RNA ribozomální 18S MeSH
The case study targeted to determine the aetiology of nodular gill disease (NGD) of farmed rainbow trout. The methods included microscopical examination of gill material in fresh, culturing of isolated organisms, histology, transmission electron microscopy and molecular biology identification. The results revealed an intravital colonization of fish gills by the testate amoeba Rhogostoma minus Belar, 1921. Rhogostoma infection was found in all fish examined microscopically (15/15); in contrast, naked amoebae related to fully developed NGD lesions were found in minority of these fish (5/15). They belonged to four genera, Acanthamoeba, Vermamoeba, Naegleria and Vannella. Results presented in this study contribute to the mosaic of findings that contrary to amoebic gill disease of marine fish turn attention to the possibility of the heterogeneous, multi-amoeba-species and multifactorial aetiology of NGD.
- Klíčová slova
- Rhogostoma minus, naked amoebae, nodular gill disease, testate amoebae,
- MeSH
- amébiáza parazitologie veterinární MeSH
- Cercozoa klasifikace izolace a purifikace fyziologie MeSH
- koinfekce MeSH
- nemoci ryb parazitologie MeSH
- Oncorhynchus mykiss parazitologie MeSH
- žábry parazitologie MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
This comprehensive review is focused on a serious protozoan disease, amebiasis. This disease is caused by the human parasite Entamoeba histolytica (E. histolytica), the second leading cause of mortality due to protozoan disease worldwide (the leading cause is malaria). The incidence of amebiasis in the Czech Republic is very low, but it may be underreported as the disease often escapes diagnosis. Intestinal colonisation by E. histolytica may be asymptomatic. The clinical picture ranges from diarrhea to colitis or fulminant colitis when the parasite progresses to the trophozoite stage. Secondary dissemination in the blood or lymph system may induce systemic signs of the disease. Liver abscess is the most common extraintestinal form of amebiasis. The diagnosis of intestinal amebiasis is based on the clinical picture and parasitological examination of the stool. To diagnose extraintestinal amebiasis, serology tests are used to detect antibodies in the blood. Recently, molecular methods have been increasingly used for the detection of the nucleic acids of the pathogen in biological specimens. The first line therapy for amebiasis are 5-nitroimidazole drugs, currently available in the Czech Republic. However, surgical intervention should also be considered in patients with a severe course of the disease. Included in the review are the case reports of patients with severe concomitant intestinal and extraintestinal amebiasis.
- MeSH
- amébiáza diagnóza farmakoterapie parazitologie MeSH
- amébová dyzenterie MeSH
- antiprotozoální látky terapeutické užití MeSH
- Entamoeba histolytica fyziologie MeSH
- lidé MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- přehledy MeSH
- Geografické názvy
- Česká republika MeSH
- Názvy látek
- antiprotozoální látky MeSH
We studied amoebae associated with nodular gill disease (NGD) outbreaks in rainbow trout Oncorhynchus mykiss (Walbaum) in fish farms in South-Western Germany. Gills of 12 diseased rainbow trout were examined in fresh, by isolation attempts, histologically and using in situ hybridisation (ISH). A total of nine amoeba strains of the genera Acanthamoeba (1), Hartmannella (2), Naegleria (1), Protacanthamoeba (1) and Vannella (4) were isolated and determined using light microscopical, ultrastructural and molecular methods. Specific molecular probes designed from the SSU rDNA sequences of individual amoeba strains were used for non-radioactive ISH in histological sections. Association of Naegleria sp. with NGD and a direct ISH proof of Naegleria trophozoites attached to hyperplastic gill epithelium are novel findings, expanding the number of possible agents of NGD and supporting the hypothesis on multicausal aetiology of this disease.
- MeSH
- amébiáza parazitologie patologie veterinární MeSH
- Amoeba klasifikace ultrastruktura MeSH
- nemoci ryb etiologie parazitologie patologie MeSH
- Oncorhynchus mykiss * MeSH
- žábry parazitologie patologie MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
New strains of non-vannellid flattened amoebae isolated from fish, an invertebrate and the marine environment were studied together with Flabellula citata Schaeffer, 1926 selected by morphology as a reference strain. The study revealed a paucity of features distinguishing individual strains at the generic level, but clearly evidenced mutual phylogenetic relationships within the assemblage of strains as well as their affiliation to the Leptomyxida. In this study, the SSU rDNA dataset of leptomyxids was expanded and a new branching pattern was presented within this lineage of Amoebozoa. Sequences of three newly introduced strains clustered in close relationship with the type strain of F. citata, the type species of the genus. Three strains, including one resembling Flamella sp., were positioned within a sister-group containing Paraflabellula spp. Results of phylogenetic analysis confirmed doubts of previous authors regarding generic assignment of several Rhizanmoeba and Ripidomnyxa strains.
- MeSH
- amébiáza genetika parazitologie veterinární MeSH
- Amoeba klasifikace izolace a purifikace ultrastruktura MeSH
- fylogeneze MeSH
- malé podjednotky ribozomu genetika MeSH
- molekulární sekvence - údaje MeSH
- nemoci ryb genetika parazitologie MeSH
- polymerázová řetězová reakce MeSH
- protozoální DNA klasifikace genetika MeSH
- ribozomální DNA klasifikace genetika MeSH
- ryby genetika parazitologie MeSH
- sekvence nukleotidů MeSH
- sekvenční analýza DNA MeSH
- sekvenční seřazení MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- protozoální DNA MeSH
- ribozomální DNA MeSH
We characterised 9 strains selected from primary isolates referable to Paramoeba/Neoparamoeba spp. Based on ultrastructural study, 5 strains isolated from fish (amoebic gill disease [AGD]-affected Atlantic salmon and dead southern bluefin tuna), 1 strain from netting of a floating sea cage and 3 strains isolated from invertebrates (sea urchins and crab) were assigned to the genus Neoparamoeba Page, 1987. Phylogenetic analyses based on SSU rDNA sequences revealed affiliations of newly introduced and previously analysed Neoparamoeba strains. Three strains from the invertebrates and 2 out of 3 strains from gills of southern bluefin tunas were members of the N. branchiphila clade, while the remaining, fish-isolated strains, as well as the fish cage strain, clustered within the clade of N. pemaquidensis. These findings and previous reports point to the possibility that N. pemaquidensis and N. branchiphila can affect both fish and invertebrates. A new potential fish host, southern bluefin tuna, was included in the list of farmed fish endangered by N. branchiphila. The sequence of P. eilhardi (Culture Collection of Algae and Protozoa [CCAP] strain 1560/2) appeared in all analyses among sequences of strain representatives of Neoparamoeba species, in a position well supported by bootstrap value, Bremer index and Bayesian posterior probability. Our research shows that isolation of additional strains from invertebrates and further analyses of relations between molecular data and morphological characters of the genera Paramoeba and Neoparamoeba are required. This complexity needs to be considered when attempting to define molecular markers for identification of Paramoeba/Neoparamoeba species in tissues of fish and invertebrates.
- MeSH
- amébiáza parazitologie veterinární MeSH
- bezobratlí parazitologie MeSH
- fylogeneze * MeSH
- Lobosea klasifikace genetika patogenita ultrastruktura MeSH
- nemoci ryb parazitologie MeSH
- protozoální DNA chemie MeSH
- ribozomální DNA chemie genetika MeSH
- Salmo salar MeSH
- sekvenční seřazení veterinární MeSH
- trofozoiti ultrastruktura MeSH
- tuňák MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- srovnávací studie MeSH
- Názvy látek
- protozoální DNA MeSH
- ribozomální DNA MeSH
Effort was made to identify Naegleria strains isolated from organs of fish, using phylogenetic analyses of SSU rDNA and ITS sequences. Eighteen fish-isolated strains studied enlarged substantially the so far available set of Naegleria strains characterized by both molecular markers. The phylogenetic analyses of separate and concatenated SSU rDNA and ITS sequences revealed phylogenetic relationships of strains under study; however, they failed to solve classification of fish-isolated strains into species. The sequence similarity of strain-representatives of Naegleria species as well as data obtained on intragenomic variation of ITS sequences discouraged the authors from the definition of new species. The results of the present study provide evidence of a need to re-evaluate the current practice of setting boundaries between species of the genus Naegleria. Sequences obtained in this study have been deposited in GenBank with accession numbers DQ768714-DQ768743.
- MeSH
- amébiáza parazitologie MeSH
- fylogeneze MeSH
- molekulární sekvence - údaje MeSH
- Naegleria klasifikace genetika MeSH
- nemoci ryb parazitologie MeSH
- ryby parazitologie MeSH
- sekvence nukleotidů MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
