Journal of Aquatic Animal Health

Herbal supplements are suitable for improving fish health and combating diseases in fish culture. However, the mechanism of action of many herbal mixtures remains unclear. This study was conducted to evaluate the effects of traditional Chinese medicine (TCM; a mix of Astragalus membranaceus, Angelica sinensis, and Crataegus hupehensis at a ratio of 1:1:1 on a weight basis) on growth, immune response, and disease resistance in Nile tilapia Oreochromis niloticus. Experimental fish (mean ± SE weight = 57 ± 1 g) were divided into two groups: a control group and a TCM (10 g/kg) group...

Fish kill investigations are critical to understanding threats to aquatic ecosystems and can serve as a measure of environmental disruption as well as an early indicator of emerging disease. The goal of this study was to analyze historical data related to such events among wild fish populations in Minnesota in order to assess the quality and completeness of the data and potential trends in fish kills. After excluding events with incomplete data (e.g., in which the location was not reported), we analyzed 225 unique fish kills from 2003 to 2013 that were recorded in two Minnesota Department of Natural Resources databases...

The rat lungworm parasite, Angiostrongylus cantonensis, is a nematode parasite that can cause potentially fatal eosinophilic meningitis in humans. The life cycle of A. cantonensis involves multiple hosts, with the most common terminal hosts being rodents and intermediate hosts comprising gastropods. One such gastropod is the invasive island apple snail, Pomacea maculata, that is native to South America but is currently established in several states in the USA, including South Carolina. It has been identified as an intermediate host for A...

Glycogen is a primary metabolic reserve in bivalves and can be suitable for the evaluation of bivalve condition and health status, but the use of glycogen as a diagnostic tool in aquaculture and biomonitoring is still relatively rare. A tissue biopsy combined with a simplified phenol-sulfuric acid method was used in this study to evaluate the inter- and intraindividual variation in the glycogen concentrations among several tissues (foot, mantle, gills, adductor muscle) of the unionid bivalve, the duck mussel Anodonta anatina...

Over the past century, populations of Lake Trout Salvelinus namaycush have declined throughout the Great Lakes basin due to overfishing, habitat destruction, introduction of invasive species, and associated recruitment issues from high thiaminase, as well as emerging infectious diseases. To combat these declines, state and federal fishery management agencies undertook substantial stock enhancement efforts, including more stringent regulation of sport and commercial catch limits and increasing hatchery propagation of Lake Trout stocked into Great Lakes basin waterways...

This study investigates the environmental factors associated with the presence of Vibrionaceae in economically important cage-cultured tropical marine fish; the Asian Seabass, Red Snapper and Hybrid Grouper. Fish samplings were conducted at monthly intervals between December 2016 and August 2017. The body weight and length of individual fish were measured, while the skin, eye, liver and kidney were sampled for bacterial isolation and identification. Water physico-chemical parameters during the sampling activities were determined, and the enumeration of total Vibrionaceae count was also conducted from water and sediment samples...

Juvenile sablefish, Anoplopoma fimbria, of length 15.3±1.6 cm and weight 68.4±4.6 g were used to assess the effects of water temperature (8, 10, 12, 14, 16, 18, and 20 °C) on hematological parameters and heat shock proteins (70 and 90) for 4 months. The hematological parameters such as red blood cell count, hematocrit, and hemoglobin were significantly decreased at 18 °C. The inorganic plasma components such as calcium and magnesium were not altered by water temperature. The organic plasma components glucose and cholesterol were notably elevated at 18 °C, whereas total protein was reduced...

The Comal River, a spring-fed system in central Texas, USA, was invaded in the 1960s by two Asian aquatic snails (Thiaridae: Melanoides tuberculata and Tarebia granifera) and, subsequently, three of their trematode parasites (Centrocestus formosanus 1990s, Haplorchis pumilio 2000s, and Philophthalmus gralli 1960s). Previous snail collections (2001-2002) established that habitat conditions significantly affect the distribution of both snail species. However, the effect of snail size (known to influence infection prevalence), and habitat conditions (known to influence snail size), on trematode infection patterns in this system was not evaluated...

The salmon louse Lepeophtheirus salmonis, a type of sea lice (family Caligidae), is enzootic in marine waters of British Columbia and poses a health risk to both farmed Atlantic Salmon Salmo salar and wild Pacific salmon Oncorhynchus spp. At the adult stage, sea lice infections can often result in severe cutaneous lesions in their salmonid hosts. To evaluate and compare the physiological consequences of adult L. salmonis infections, smolts of Atlantic Salmon and Sockeye Salmon O. nerka were exposed to 2 (low), 6 (medium), or 10 (high) adult female lice/fish...

The present study supports the usefulness of ancillary techniques such as immunohistochemistry as a valid diagnostic tool in the field of fish oncology. The immunohistochemical patterns observed in four neoplasms, in four individual teleosts belonging to different species are here described. Cytokeratin, vimentin, actin, S-100, calretinin, and melan A antibodies were used. Diagnoses of papilloma in Abramis brama, fibroma in Lythognatus mormyrus, schwannoma in Carassius carassius and melanoma in a spontaneously inbred Xyphophorus hybrid were made...

The genus Aeromonas comprises more than 60 recognized species that include many important fish pathogens such as the causative agents of furunculosis, and motile Aeromonas septicemia (MAS). Although MAS is typically considered a secondary infection, a new virulent A. hydrophila (vAh) strain has been causing devastating losses to the catfish industry in Alabama since 2009. The objective of this study was to characterize the spatiotemporal distribution of Aeromonas sp. and, specifically, vAh in a commercial catfish farm in West Alabama...

During a routine health inspection of apparently healthy wild-caught common mudpuppies Necturus maculosus, the bacteria Yersinia ruckeri was isolated and the identity confirmed using biochemical and molecular methods. This represents the first isolation of Y. ruckeri from an amphibian. This finding increases the known host range capable of harboring this important fish pathogen and could have serious management implications for aquaculture. Furthermore, addressing wild amphibians in fish hatchery biosecurity plans is discussed...

In September 2016, a marine fish farm operator in Selangor, Malaysia reported a disease outbreak affecting juvenile Hybrid Groupers (Camouflage Grouper Epinephelus polyphekadion x Tiger Grouper E. fuscoguttatus). The average daily mortality was 120 fish, resulting in a cumulative mortality rate of 29% within 10 days. The affected Hybrid Groupers displayed lethargy, excessive mucus production, rotten fins, congestion of livers and kidneys, and enlargement of spleens. Microscopically, there were generalize congestion of the brains and internal organs...

The ability of formalin, PEROX-AID® (hydrogen peroxide), and seawater to kill waterborne Nanophyetus salmincola cercariae was evaluated in vitro. Newly emerged cercariae survived for extended periods in freshwater, with 53-73% survival occurring in negative control groups after 24 hr. Exposure to dilutions of formalin reduced this survival time, with 0% of cercariae surviving after 30 min. in 450 μL / L, 40 min. in 225 μL / L, and 300 min. in 113 μL / L. Exposure to PEROX-AID® (hydrogen peroxide) for one hour resulted in reduced cercarial survival (16...

Matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) is a rapid, cost-effective method for identification of a broad range of bacterial taxa, but its accuracy for Vibrio spp. from samples of aquatic animal origin is unknown. We used DNA sequence analysis targeting two conserved genes, rpoB and rpoD, as the identification standard for 5 reference strains and 35 Vibrio spp. field isolates obtained from diagnostic aquaculture samples. Overall, MALDI-TOF MS correctly identified 100% of the five reference strains to the genus level and 80% (4 of 5) to the species level...

Coelomic fluid aspiration has been utilized in echinoderms in research and clinical settings. Detailed procedural descriptions for coelomic fluid sampling in sea urchins (class Echinoidea) are lacking, and samples are prone to contamination. The objectives of this study were to (1) standardize a technique for coelomic fluid collection in long-spined sea urchin Diadema antillarum that optimizes the diagnostic quality of the sample utilizing diagnostic imaging, (2) identify coelomic fluid bacterial isolates (using Biolog GEN III MicroLog and 16s rDNA sequencing), and (3) compare positive cultures to animal weight, holding time prior to sampling, water temperature, and gross fluid appearance...

Indigenous small cyprinid fish species play an important role in Great Lakes ecosystems and also comprise the backbone of a multimillion-dollar baitfish industry. Due to their widespread use in sport fisheries of the Laurentian Great Lakes, there are increasing concerns that baitfish may introduce or disseminate fish pathogens. In this study, we evaluated whether baitfish purchased from 78 randomly selected retail bait dealers in Michigan harbored fish viruses. Between September 2015 and June 2016, 5,400 baitfish divided into 90 lots of 60 fish were purchased...

The present study was conducted to explore the occurrence of Flavobacteriaceae in wild (n = 108) and farmed (n = 187) Nile Tilapia (Oreochromis niloticus) collected from Lake Victoria and twelve ponds in the Morogoro region, respectively. The size of the ponds surveyed ranged from 130 - 150 m2 . Ponds parameters and fish morphometric data were recorded during sampling. A total of 67 (farmed n = 44 and wild = 23) Flavobacterium-like isolates were identified on the basis of colony morphology and biochemical tests...

Global amphibian decline continues to be a great concern despite our increased understanding of the causes behind the observed patterns of the decline, such as habitat modification and infectious diseases. Although there is a large body of literature on the topic of amphibian infectious diseases, pathogen prevalence and distribution among entire communities of species in many regions remain poorly understood. In addition to these geographic gaps in our understanding, past work has focused largely on individual pathogens, either Batrachochytrium dendrobatidis (Bd) or ranavirus (RV), rather than dual infection rates among host species...

The newly-emerging tissue microbiota hypothesis suggests that bacteria found in blood and tissues play a role in host health, as these bacterial communities have been associated with various non-communicable diseases such as obesity, liver disease, and cardiovascular disease. Numerous reports identify bacteria in the blood of healthy finfish, indicating bacteremia may not always indicate disease. Current research priorities in aquaculture include the development of technologies and practices that will allow effective reduction in antibiotic use for prevention and treatment of disease...