Recognition of Dominance in the Big-Clawed Snapping Shrimp (Alpheus heterochaelis Say 1818) Part II: Analysis of Signal Modality

Alpheus heterochaelis is able to recognise the dominance status of an opponent (see Part I of this series). A former loser does not fight against a former winner but rather escapes immediately after a contact. However, if a former loser meets an inexperienced opponent, the loser fights against it. Here we investigated the signal used for dominance recognition. Two groups of snapping shrimp that had lost a fight on Day 1, intact animals, and shrimp with cut lateral antennular filaments (i.e. without chemosensory aesthetascs), fought against the same winner on Day 2. Intact losers showed escape behaviour, while losers without aesthetascs showed almost the same aggressive behaviour as on Day 1. The main signal in dominance recognition is therefore a chemical one, possibly the urine or a substance carried by it. The main receptor organs for this signal are the lateral filaments of the antennules carrying the aesthetascs.     

Snapping behaviour in intraspecific agonistic encounters in the snapping shrimp (Alpheus heterochaelis)

During intraspecific agonistic encounters in snapping shrimp (Alpheus heterochaelis) the behaviour of the snapper, emitting a fast water jet by very rapid closure of the large modified snapper claw, and the receiver was analysed by single frame video analysis before, during, and after the snap. During snapping the opponents usually face each other. Snapping is most frequently preceded by touch of frontal appendages. The snapping animal keeps its snapper claw slightly across the midline, shielding frontal body parts, and its tailfan bent downwards. The mean claw cocking duration (generating muscle tension) before snapping amounts to about 500 ms. In 58% of the snaps, the snapper claw pointed at the opponent, its claws, densely covered with sensory hairs, representing the main target of the water jet. The mean distance for these directed snaps was 0.9 cm, while undirected snaps were emitted from larger distances of on average 3.4 cm. The snapper usually withdraws immediately after snapping, the receiver approaches. Initial snaps are often answered by return snaps and both are emitted from smaller distances and hit more often than subsequent snaps.     

Flow visualisation and high speed video analysis of water jets in the snapping shrimp (Alpheus heterochaelis)

Snapping shrimp (Alpheus heterochaelis) produce a fast, well-focused water jet by rapid closure of their specialised snapper claw. As shown previously, water jets may injure the opponent in interspecific encounters (e.g. with small crabs) although no damage was observed in intraspecific encounters. For conspecific receivers the jet represents a potential hydrodynamic signal and can be analysed with the help of mechanosensory hairs. To gain more insight in the biophysical characteristics of the water jet we visualised and analysed jets of tethered snapping shrimp using standard and high speed video recordings. Water jet width increases with increasing distance from the snapper claw tip, and both width and distance increase with increasing snapper claw size. Water jet distances do not increase with increasing claw cocking duration (building up muscle tension) but medium cocking durations of about 550 ms result in longest distances. Mean water jet velocity is 6.5 m s⁻¹ shortly after claw closure but rapidly decreases subsequently. At the mean distance between snapping conspecifics (9 mm) water jet velocities produced by snapping shrimp with larger snapper claws are significantly higher than those of animals with smaller claws. Interestingly, males with equal snapper claw size as females produce significantly faster water jets. Accepted: 31 March 1999     

The modality of the dominance signal in snapping shrimp (Alpheus heterochaelis) and the corresponding setal types on the antennules

Previous behavioural experiments showed that snapping shrimp lacking lateral antennular filaments, i.e. without chemosensory aesthetascs, lose the ability to distinguish between conspecifics that are inexperienced in fighting and former winners. A chemosensory dominance signal was assumed to be present, although other receptors unique to the lateral filaments may have been responsible for the behavioural changes. In the present study, the antennules of snapping shrimp were examined for differences between the lateral and medial antennule filaments to identify the modality of the dominance signal. We found six different types of setae and two types of pores. A new probably bimodal setal type is described, the broad long simple seta. Only the chemosensory aesthetascs and their associated hydrosensory companion setae are unique to the lateral filament. Thus we conclude that the dominance signal is chemical, because a hydrodynamic signal would be also received by the simple setae distributed on both filaments.     

The modality of the dominance signal in snapping shrimp (Alpheus heterochaelis) and the corresponding setal types on the antennules

Previous behavioural experiments showed that snapping shrimp lacking lateral antennular filaments, i.e. without chemosensory aesthetascs, lose the ability to distinguish between conspecifics that are inexperienced in fighting and former winners. A chemosensory dominance signal was assumed to be present, although other receptors unique to the lateral filaments may have been responsible for the behavioural changes. In the present study, the antennules of snapping shrimp were examined for differences between the lateral and medial antennule filaments to identify the modality of the dominance signal. We found six different types of setae and two types of pores. A new probably bimodal setal type is described, the broad long simple seta. Only the chemosensory aesthetascs and their associated hydrosensory companion setae are unique to the lateral filament. Thus we conclude that the dominance signal is chemical, because a hydrodynamic signal would be also received by the simple setae distributed on both filaments.     

Agonistic Behaviour and Development of Territoriality During Ontogeny of the Sea Anemone Dwelling Crab Allopetrolisthes Spinifrons (H. Milne Edwards, 1837) (Decapoda: Anomura: Porcellanidae)

Allopetrolisthes spinifrons is an ectosymbiotic crab of the sea anemone Phymactis clematis . As a consequence of low host abundance, these represent a scarce and limited resource for the crab. Additionally, the relatively small size of the sea anemone host suggests that few symbiotic crabs can cohabit on one host individual, forcing crabs to adopt a territorial behaviour. In order to examine the potential presence and ontogenetic development of territoriality, the agonistic behaviour between crabs of various ontogenetic stages (adults, juveniles, and recruits) was studied in the laboratory. Laboratory experiments demonstrated that adult or juvenile crabs aggressively defended their sea anemone hosts against adult or juvenile intruders, respectively, but both adult and juvenile crabs tolerated recruits. Adult crabs behaved indifferently towards juvenile crabs, sometimes tolerating them, sometimes expelling them. Recruits never showed agonistic behaviour among themselves. The agonistic interactions observed in the laboratory and the uniform population distribution pattern on sea anemones recently described for A . spinifrons indicate that this species exhibits territorial behaviour, which develops during ontogeny. Territoriality in this species and other symbiotic decapods may function as a density-dependent mechanism of population regulation, being mediated by the availability of hosts. Resource monopolisation behaviours may be common among other symbiotic and free-living marine invertebrates inhabiting discrete habitats that represent a limiting resource.     

Agonistic Behaviour and Development of Territoriality During Ontogeny of the Sea Anemone Dwelling Crab Allopetrolisthes Spinifrons (H. Milne Edwards, 1837) (Decapoda: Anomura: Porcellanidae)

Allopetrolisthes spinifrons is an ectosymbiotic crab of the sea anemone Phymactis clematis. As a consequence of low host abundance, these represent a scarce and limited resource for the crab. Additionally, the relatively small size of the sea anemone host suggests that few symbiotic crabs can cohabit on one host individual, forcing crabs to adopt a territorial behaviour. In order to examine the potential presence and ontogenetic development of territoriality, the agonistic behaviour between crabs of various ontogenetic stages (adults, juveniles, and recruits) was studied in the laboratory. Laboratory experiments demonstrated that adult or juvenile crabs aggressively defended their sea anemone hosts against adult or juvenile intruders, respectively, but both adult and juvenile crabs tolerated recruits. Adult crabs behaved indifferently towards juvenile crabs, sometimes tolerating them, sometimes expelling them. Recruits never showed agonistic behaviour among themselves. The agonistic interactions observed in the laboratory and the uniform population distribution pattern on sea anemones recently described for A. spinifrons indicate that this species exhibits territorial behaviour, which develops during ontogeny. Territoriality in this species and other symbiotic decapods may function as a density-dependent mechanism of population regulation, being mediated by the availability of hosts. Resource monopolisation behaviours may be common among other symbiotic and free-living marine invertebrates inhabiting discrete habitats that represent a limiting resource.     

Characterization of the bacterial microbiota of Biomphalaria glabrata (Say, 1818) (Mollusca: Gastropoda) from Brazil

Roughly 200 000 000 people in 74 countries infected with schistosomes all share the fact that they came in contact freshwater harbouring infected snails. The aim of the study is to characterize the microbiota of wild and laboratory‐reared snails of Biomphalaria glabrata from Pernambuco, Brazil. The microbiota of these molluscs was identified biochemically by the VITEK 2 automated microbiological system. Antimicrobial susceptibility testing was carried out by the disc diffusion method with ß‐lactam antibiotics, aminoglycosides, quinolones, folate pathway inhibitors, fenicols and tetracyclines. The results showed that all bacteria identified were gram‐negative, including 11 bacterial genera: Aeromonas, Citrobacter, Enterobacter, Cupriavidus, Rhizobium, Stenotrophomonas, Pseudomonas, Klebsiella, Acinetobacter, Vibrio and Sphingomonas. Regarding the antimicrobial susceptibility, all the isolates exhibited resistance to amoxicillin and sensitivity to meropenem (beta‐lactam antimicrobials). The microbiota of the wild snails consisted predominantly of Enterobacter cloacae, while the laboratory‐reared snails predominantly showed Citrobacter freundii and Aeromonas sobria.

Significance and Impact of the Study

Biomphalaria glabrata is a Brazilian freshwater Planorbidae of great medical relevance as an intermediate host of Schistosoma mansoni. About a month after being infected by one or more miracidia larvae of a compatible schistosome, B. glabrata sheds thousands of cercariae into the water where they seek human skin and, if successful, penetrate to establish infection, eventually taking up residence and maturing in blood vessels of the small intestine. Results obtained from this study aim at targeting novel biological control strategies for schistosomiasis such as paratransgenesis. This is the first study on the microbiota of B. glabrata from Brazil.     

The effects of food and density of the movement ofArion ater andAriolimax columbianus (Pulmonata: Stylommatophora) between habitats

Experiments were conducted to determine if slug density, or food quantity and quality could cause dispersal by slugs. Arion ater dispersed quickly from overcrowded areas, where high mortality was incurred by this species. Poor food conditions, caused more dispersal than good food conditions, but food had no effect on the mortality of A. ater. Neither food nor density factors had significant effects on the dispersal of Ariolimax columbianus. However, more A. columbianus died in the high- than low-density treatments. A. columbianus mortality was unaffected by the food factor. Dispersing Arion were heavier than non-dispersers, but there was no difference between the weights of dispersing and non-dispersing Ariolimax. There were significant seasonal changes in the dispersal rate, mortality and weight of dispersing Arion, whereas only the mortality of Ariolimax changed significantly during the experiments. Since Arion ater did not markedly reduce its activity during unsuitable weather it was able to leave areas of poor food and high slug density fairly rapidly. Ariolimax columbianus' large size allowed it to remain inactive during unfavourable weather and permitted this species to be relatively unresponsive to the experimental treatments.     

Establishment of the comet assay in the freshwater snail Biomphalaria glabrata (Say, 1818)

The single cell gel eletrophoresis or the comet assay was established in the freshwater snail Biomphalaria glabrata. For detecting DNA damage in circulating hemocytes, adult snails were irradiated with single doses of 2.5, 5, 10 and 20 Gy of ⁶⁰Co gamma radiation. Genotoxic effect of ionizing radiation was detected at all doses as a dose-related increase in DNA migration. Comet assay in B. glabrata demonstrated to be a simple, fast and reliable tool in the evaluation of genotoxic effects of environmental mutagens.     

Molecular Mechanism of GTPase Activation at the Signal Recognition Particle (SRP) RNA Distal End

The signal recognition particle (SRP) RNA is a universally conserved and essential component of the SRP that mediates the co-translational targeting of proteins to the correct cellular membrane. During the targeting reaction, two functional ends in the SRP RNA mediate distinct functions. Whereas the RNA tetraloop facilitates initial assembly of two GTPases between the SRP and SRP receptor, this GTPase complex subsequently relocalizes ∼100 Å to the 5′,3′-distal end of the RNA, a conformation crucial for GTPase activation and cargo handover. Here we combined biochemical, single molecule, and NMR studies to investigate the molecular mechanism of this large scale conformational change. We show that two independent sites contribute to the interaction of the GTPase complex with the SRP RNA distal end. Loop E plays a crucial role in the precise positioning of the GTPase complex on these two sites by inducing a defined bend in the RNA helix and thus generating a preorganized recognition surface. GTPase docking can be uncoupled from its subsequent activation, which is mediated by conserved bases in the next internal loop. These results, combined with recent structural work, elucidate how the SRP RNA induces GTPase relocalization and activation at the end of the protein targeting reaction.     

Nickel-quinolones interaction. Part 2 - Interaction of nickel(II) with the antibacterial drug oxolinic acid

The mononuclear nickel(II) complexes with the first-generation quinolone antibacterial agent oxolinic acid in the presence or absence of nitrogen-donor heterocyclic ligands (2,2′-bipyridine, 1,10-phenanthroline or pyridine) have been synthesized and characterized. The experimental data suggest that oxolinic acid acts as deprotonated bidentate ligand coordinated to Ni(II) ion through the ketone and carboxylato oxygens. The crystal structure of (2,2′-bipyridine)bis(oxolinato) nickel(II), 2 has been determined by X-ray crystallography. The cyclic voltammograms of the complexes recorded in dmso solution and in 1/2 dmso/buffer (containing 150 mM NaCl and 15 mM trisodium citrate at pH 7.0) solution have shown that in the presence of calf-thymus DNA (CT DNA) they can bind to CT DNA by the intercalative binding mode. UV study of the interaction of the complexes with CT DNA has shown that the complexes bind to CT DNA and bis(aqua)bis(oxolinato) nickel(II) exhibits the highest binding constant to CT DNA. Competitive study with ethidium bromide (EB) has shown that the complexes can displace the DNA-bound EB indicating that they bind to DNA in strong competition with EB. The complexes exhibit good binding propensity to human or bovine serum albumin protein having relatively high binding constant values.     

Nickel-quinolones interaction. Part 1 - Nickel(II) complexes with the antibacterial drug sparfloxacin: Structure and biological properties

The mononuclear nickel(II) complexes with the third-generation quinolone antibacterial agent sparfloxacin in the absence or presence of nitrogen donor heterocyclic ligands (1,10-phenanthroline or 2,2′-bipyridine) have been synthesized and characterized. The experimental data suggest that sparfloxacin acts as deprotonated bidentate ligand coordinated to Ni(II) ion through the ketone and carboxylato oxygens. The crystal structure of (1,10-phenanthroline)bis(sparfloxacinato) nickel(II), 2 has been determined by X-ray crystallography. The cyclic voltammograms of the complexes recorded in dmso solution and in 1/2 dmso/buffer (containing 150 mM NaCl and 15 mM trisodium citrate at pH 7.0) solution have shown that in the presence of CT DNA they can bind to CT DNA by the intercalative binding mode. UV study of the interaction of the complexes with calf-thymus DNA (CT DNA) has shown that the complexes can bind to CT DNA and 2 exhibits the highest binding constant to CT DNA. Competitive study with ethidium bromide (EB) has shown that the complexes can displace the DNA-bound EB indicating that they bind to DNA in strong competition with EB for the intercalative binding site. The antimicrobial activity of the complexes has been tested on three different microorganisms and has revealed that the inhibition provided by the complexes is slightly decreased in comparison to free sparfloxacin. The complexes exhibit good binding propensity to human and bovine serum albumin proteins having relatively high binding constant values.     

Nickel-quinolones interaction: Part 3 — Nickel(II) complexes of the antibacterial drug flumequine

Nickel(II) complexes with the first-generation quinolone antibacterial agent flumequine in the presence or absence of nitrogen donor heterocyclic ligands (4-benzylpyridine, pyridine, 2,2′-bipyridine or 1,10-phenanthroline) have been structurally characterized by physicochemical and spectroscopic techniques. The experimental data suggest that flumequine acts as deprotonated bidentate ligand coordinated to Ni(II) through the carboxylato and ketone oxygen atoms. The crystal structures of bis(4-benzylpyridine)bis(flumequinato)nickel(II) 2, (2,2′-bipyridine)bis(flumequinato)nickel(II) 4 and (1,10-phenanthroline)bis(flumequinato)nickel(II) 5 have been determined by X-ray crystallography and are the first crystal structures of flumequinato complexes reported. UV study of the interaction of the complexes with calf-thymus DNA (CT DNA) has shown that the complexes bind to CT DNA and bis(aqua)bis(flumequinato)nickel(II) exhibits the highest binding constant to CT DNA. Competitive study with ethidium bromide (EB) has shown that the complexes can displace the DNA-bound EB indicating that they bind to DNA in strong competition with EB. The cyclic voltammograms of the complexes recorded in DMSO solution and in 1/2 DMSO/buffer (containing 150 mM NaCl and 15 mM trisodium citrate at pH 7.0) solution have shown that in the presence of CT DNA they bind to CT DNA by the intercalative binding mode. The complexes exhibit good binding propensity to human or bovine serum albumin protein having relatively high binding constant values.     

Influence of Echinostoma paraensei (Lie and Basch, 1967) infection on the calcium content in Biomphalaria glabrata (Say, 1818)

The calcium content in the hemolymph and shell of Biomphalaria glabrata (Say, 1818) was determined after exposure to different parasite burdens (5 and 50 miracidia) of Echinostoma paraensei (Lie and Basch, 1967). The snails were dissected 1, 2, 3, and 4 weeks after infection to collect the hemolymph and shell. An increase in calcemia was observed in snails infected with both miracidial doses. A significant decrease in the calcium ions in the shell was observed, coinciding with the calcemia peak in the hemolymph. This indicates greater mobilization of calcium between the shell and hemolymph to regulate the calcium content in the body when the snail is exposed to stress conditions, as has also been observed in some other infected snail species. The results obtained indicate that in this model, the calcium metabolism depends on the miracidial dose used.     

Within-shelter behaviour of the spotted spiny lobster, Panulirus guttatus (latreille), in simulated communal dens: an exploratory study

Panulirus guttatus is a sedentary spiny lobster that dwells in the coral reef habitat. We conducted an exploratory study to describe the within-shelter behaviour of groups of 4-6 individuals of P. guttatus in simulated communal dens deployed in tanks. Lobsters displayed a diel within-shelter activity rhythm, with a peak shortly before dawn due to an increase in agonistic interactions among sheltered individuals. In a single-chamber cave, aggressions resulted in the constant rearrangement of individuals in the den, related to their preference to cling to the walls. In a triple-chamber cave, the largest male often defended one chamber, but the remaining individuals tended to aggregate in one of the other two chambers during the day. These trends suggest that P. guttatus is a gregarious lobster, but that this gregariousness is influenced by the amount of available shelters and by temporary, size-related social hierarchies. This hypothesis should be tested with fully replicated experiments to help understand the patterns of shelter utilization of P. guttatus in the coral reef habitat.     

Comprehensive Compositional Analysis of Plant Cell Walls (Lignocellulosic biomass) Part II: Carbohydrates

The need for renewable, carbon neutral, and sustainable raw materials for industry and society has become one of the most pressing issues for the 21st century. This has rekindled interest in the use of plant products as industrial raw materials for the production of liquid fuels for transportation² and other products such as biocomposite materials⁶. Plant biomass remains one of the greatest untapped reserves on the planet⁴. It is mostly comprised of cell walls that are composed of energy rich polymers including cellulose, various hemicelluloses, and the polyphenol lignin⁵ and thus sometimes termed lignocellulosics. However, plant cell walls have evolved to be recalcitrant to degradation as walls contribute extensively to the strength and structural integrity of the entire plant. Despite its necessary rigidity, the cell wall is a highly dynamic entity that is metabolically active and plays crucial roles in numerous cell activities such as plant growth and differentiation⁵. Due to the various functions of walls, there is an immense structural diversity within the walls of different plant species and cell types within a single plant⁴. Hence, depending of what crop species, crop variety, or plant tissue is used for a biorefinery, the processing steps for depolymerisation by chemical/enzymatic processes and subsequent fermentation of the various sugars to liquid biofuels need to be adjusted and optimized. This fact underpins the need for a thorough characterization of plant biomass feedstocks. Here we describe a comprehensive analytical methodology that enables the determination of the composition of lignocellulosics and is amenable to a medium to high-throughput analysis (Figure 1). The method starts of with preparing destarched cell wall material. The resulting lignocellulosics are then split up to determine its monosaccharide composition of the hemicelluloses and other matrix polysaccharides1, and its content of crystalline cellulose⁷. The protocol for analyzing the lignin components in lignocellulosic biomass is discussed in Part I³.     

Physiological changes in Biomphalaria glabrata Say, 1818 (Pulmonata: Planorbidae) caused by sub-lethal concentrations of the latex of Euphorbia splendens var. hislopii N.E.B (Euphorbiaceae)

Molluscides have been used as one of the strategies to control schistosomiasis. Many plant extracts with molluscidal effects have been tested, but the action of the latex of Euphorbia splendens var. hislopii is considered the most promising because it meets the recommendations of the World Health Organization (WHO). The objective of this study was to determine the lethal dose and identify the effects of the different doses of latex of E. splendens var. hislopii on the physiology of Biomphalaria glabrata submitted to treatment for 24 h. The concentrations of glucose, uric acid and total proteins in the hemolymph and of glycogen in the digestive gland and cephalopodal mass were determined. The LD50 value was 1 mg/l. The highest escape index was found to be at a concentration of 0.6 mg/l. The results showed that the latex of E. splendens var. hislopii caused a sharp reduction in the reserves of glycogen in the digestive gland and elevation of the protein content in the hemolymph of B. glabrata.     

Selenium homeostasis in human brain cells: Effects of copper (II) and Se species

BackgroundBoth essential trace elements selenium (Se) and copper (Cu) play an important role in maintaining brain function. Homeostasis of Cu, which is tightly regulated under physiological conditions, seems to be disturbed in Alzheimer´s (AD) and Parkinson´s disease (PD) patients. Excess Cu promotes the formation of oxidative stress, which is thought to be a major cause for development and progression of neurological diseases (NDs). Most selenoproteins exhibit antioxidative properties and may counteract oxidative stress. However, expression of selenoproteins is altered under conditions of Se deficiency. Serum Se levels are decreased in AD and PD patients suggesting Se as an important factor in the development and progression of NDs. The aim of this study was to elucidate the interactions between Cu and Se in human brain cells particularly with respect to Se homeostasis.MethodsFirstly, modulation of Se status by selenite or SeMet were assessed in human astrocytes and human differentiated neurons. Therefore, cellular total Se content, intra- and extracellular selenoprotein P (SELENOP) content, and glutathione peroxidase (GPX) activity were quantified. Secondly, to investigate the impact of Cu on these markers, cells were exposed to copper(II)sulphate (CuSO₄) for 48 h. In addition, putative protective effects of Se on Cu-induced toxicity, as measured by cell viability, DNA damage, and neurodegeneration were investigated.ResultsModulation of cellular Se status was strongly dependent on Se species. In detail, SeMet increased total cellular Se and SELENOP content, whereas selenite led to increased GPX activity and SELENOP excretion. Cu treatment resulted in 133-fold higher cellular Cu concentration with a concomitant decrease in Se content. Additionally, SELENOP excretion was suppressed in both cell lines, while GPX activity was diminished only in astrocytes. These effects of Cu could be partially prevented by the addition of Se depending on the cell line and Se species used. While Cu-induced oxidative DNA damage could not be prevented by addition of Se regardless of chemical species, SeMet protected against neurite network degeneration triggered by Cu.ConclusionCu appears to negatively affect Se status in astrocytes and neurons. Especially with regard to an altered homeostasis of those trace elements during aging, this interaction is of high physiological relevance. Increasing Cu concentrations associated with decreased selenoprotein expression or functionality might be a promoting factor for the development of NDs.     

Virus diseases of farmed shrimp in the Western Hemisphere (the Americas): a review

Penaeid shrimp aquaculture is an important industry in the Americas, and the industry is based almost entirely on the culture of the Pacific White Shrimp, Litopenaeus vannamei. Western Hemisphere shrimp farmers in 14 countries in 2004 produced more than 200,000 metric tons of shrimp, generated more than $2 billion in revenue, and employed more than 500,000 people. Disease has had a major impact on shrimp aquaculture in the Americas since it became a significant commercial entity in the 1970s. Diseases due to viruses, rickettsial-like bacteria, true bacteria, protozoa, and fungi have emerged as major diseases of farmed shrimp in the region. Many of the bacterial, fungal and protozoan caused diseases are managed using improved culture practices, routine sanitation, and the use of chemotherapeutics. However, the virus diseases have been far more problematic to manage and they have been responsible for the most costly epizootics. Examples include the Taura syndrome pandemic that began in 1991-1992 when the disease emerged in Ecuador, and the subsequent White Spot Disease pandemic that followed its introduction to Central America from Asia in 1999. Because of their socioeconomic significance to shrimp farming, seven of the nine crustacean diseases listed by the World Animal Organization (OIE) are virus diseases of shrimp. Of the seven virus diseases of penaeid shrimp, five are native to the Americas or have become enzootic following their introduction. The shrimp virus diseases in the Americas are increasingly being managed by exclusion using a combination of biosecurity and the practice of culturing domesticated specific pathogen-free (SPF) stocks or specific pathogen-resistant (SPR) stocks. Despite the significant challenges posed by disease, the shrimp farming industry of the Americas has responded to the challenges posed by disease and it has developed methods to manage its diseases and mature into a sustainable industry.