A New Pathogenic Virus in the Caribbean Spiny Lobster Panulirus argus from the Florida Keys

A pathogenic virus was diagnosed from juvenile Caribbean spiny lobsters Panulirus argus from the Florida Keys. Moribund lobsters had characteristically milky hemolymph that did not clot. Altered hyalinocytes and semigranulocytes, but not granulocytes, were observed with light microscopy. Infected hemocytes had emarginated, condensed chromatin, hypertrophied nuclei and faint eosinophilic Cowdry-type-A inclusions. In some cases, infected cells were observed in soft connective tissues. With electron microscopy, unenveloped, nonoccluded, icosahedral virions (182 +/- 9 nm SD) were diffusely spread around the inner periphery of the nuclear envelope. Virions also occurred in loose aggregates in the cytoplasm or were free in the hemolymph. Assembly of the nucleocapsid occurred entirely within the nucleus of the infected cells. Within the virogenic stroma, blunt rod-like structures or whorls of electron-dense granular material were apparently associated with viral assembly. The prevalence of overt infections, defined as lethargic animals with milky hemolymph, ranged from 6 to 8 % with certain foci reaching prevalences of 37 %. The disease was transmissible to uninfected lobsters using inoculations of raw hemolymph from infected animals. Inoculated animals became moribund 5 to 7 d before dying and they began dying after 30 to 80 d post-exposure. The new virus is apparently widespread, infectious, and lethal to the Caribbean spiny lobster. Given the pathogenic nature of the virus, further characterization of the disease agent is warranted

A Review of the Lethal Spiny Lobster Virus PaV1 - Ten Years After Its Discovery

In 1999, we discovered that juvenile Caribbean spiny lobsters (Panulirus argus) in the Florida Keys were infected with PaV1 (Panulirus argus virus 1), the first naturally occurring pathogenic virus reported from lobsters. The virus profoundly affects their biology and ecology. PaV1 is probably wide-spread in the Caribbean with confirmed infections from the United States (Florida), St Croix, Mexico, and Belize; and anecdotal reports from the Bahamas and Cuba. Mean prevalence in the Florida Keys has been stable since 1999 (5 - 8%), but has risen from 2.7% to 10.9% in Mexico (Puerto Morelos), the only other country where it has been studied extensively. The disease is most prevalent (\u3e 15%) in the smallest juveniles lobsters (\u3c 20 mm carapace length) and declines in prevalence among larger juveniles and adults. Although adults do not present the characteristic signs of this disease, they can harbor the virus with PCR-confirmed infections of adult, fishery-caught lobsters of 11 and 50% in Florida and Belize, respectively. The virus is lethal; infected lobsters die over one to several months with more rapid mortality for small juveniles. Infected lobsters become increasingly sedentary and cease feeding, often dying of metabolic exhaustion. Routes of viral transmission include ingestion, contact, and for early benthic juveniles, transmission through seawater over a few meters. Recent studies show that PaV1 is not viable in seawater for more than a few days, but larvae and postlarvae can be carriers over potentially long distances. Lobster ecology is dramatically altered during the course of infection. Prior to infectiousness, healthy lobsters avoid diseased lobsters, presumably reducing their risk of infection and resulting in infected juvenile lobsters dwelling alone rather than in groups. Avoidance results in increased shelter competition between healthy and diseased lobsters, with greater predation on the increasingly lethargic and solitary infected lobsters. Little is known about the prevalence or impact of PaV1 outside of Mexico and the United States, but the disease threatens fisheries throughout the pan-Caribbean range of P. argus. Marine diseases are emerging at an accelerated rate and the tools and knowledge that we develop through the study of diseases such as PaV1 will be invaluable in addressing future epizootics

Reward and reinforcement activity in the nucleus accumbens during learning

The nucleus accumbens core (NAcc) has been implicated in learning associations between sensory cues and profitable motor responses. However, the precise mechanisms that underlie these functions remain unclear. We recorded single-neuron activity from the NAcc of primates trained to perform a visual-motor associative learning task. During learning, we found two distinct classes of NAcc neurons. The first class demonstrated progressive increases in firing rates at the go-cue, feedback/tone and reward epochs of the task, as novel associations were learned. This suggests that these neurons may play a role in the exploitation of rewarding behaviors. In contrast, the second class exhibited attenuated firing rates, but only at the reward epoch of the task. These findings suggest that some NAcc neurons play a role in reward-based reinforcement during learning

Behavioral Immunity Suppresses an Epizootic in Caribbean Spiny Lobsters

Sociality has evolved in a wide range of animal taxa but infectious diseases spread rapidly in populations of aggregated individuals, potentially negating the advantages of their social interactions. To disengage from the coevolutionary struggle with pathogens, some hosts have evolved various forms of behavioral immunity ; yet, the effectiveness of such behaviors in controlling epizootics in the wild is untested. Here we show how one form of behavioral immunity (i.e., the aversion of diseased conspecifics) practiced by Caribbean spiny lobsters (Panulirus argus) when subject to the socially transmitted PaV1 virus, appears to have prevented an epizootic over a large seascape. We capitalized on a natural experiment in which a die-off of sponges in the Florida Keys (USA) resulted in a loss of shelters for juvenile lobsters over a similar to 2500km(2) region. Lobsters were thus concentrated in the few remaining shelters, presumably increasing their exposure to the contagious virus. Despite this spatial reorganization of the population, viral prevalence in lobsters remained unchanged after the sponge die-off and for years thereafter. A field experiment in which we introduced either a healthy or PaV1-infected lobster into lobster aggregations in natural dens confirmed that spiny lobsters practice behavioral immunity. Healthy lobsters vacated dens occupied by PaV1-infected lobsters despite the scarcity of alternative shelters and the higher risk of predation they faced when searching for a new den. Simulations from a spatially-explicit, individual-based model confirmed our empirical results, demonstrating the efficacy of behavioral immunity in preventing epizootics in this system

Behavioral Immunity Suppresses an Epizootic in Caribbean Spiny Lobsters

Sociality has evolved in a wide range of animal taxa but infectious diseases spread rapidly in populations of aggregated individuals, potentially negating the advantages of their social interactions. To disengage from the coevolutionary struggle with pathogens, some hosts have evolved various forms of behavioral immunity ; yet, the effectiveness of such behaviors in controlling epizootics in the wild is untested. Here we show how one form of behavioral immunity (i.e., the aversion of diseased conspecifics) practiced by Caribbean spiny lobsters (Panulirus argus) when subject to the socially transmitted PaV1 virus, appears to have prevented an epizootic over a large seascape. We capitalized on a natural experiment in which a die-off of sponges in the Florida Keys (USA) resulted in a loss of shelters for juvenile lobsters over a ~2500km2 region. Lobsters were thus concentrated in the few remaining shelters, presumably increasing their exposure to the contagious virus. Despite this spatial reorganization of the population, viral prevalence in lobsters remained unchanged after the sponge die-off and for years thereafter. A field experiment in which we introduced either a healthy or PaV1-infected lobster into lobster aggregations in natural dens confirmed that spiny lobsters practice behavioral immunity. Healthy lobsters vacated dens occupied by PaV1-infected lobsters despite the scarcity of alternative shelters and the higher risk of predation they faced when searching for a new den. Simulations from a spatially-explicit, individual-based model confirmed our empirical results, demonstrating the efficacy of behavioral immunity in preventing epizootics in this system

Lateralization of mesial temporal lobe epilepsy with chronic ambulatory electrocorticography

Objective Patients with suspected mesial temporal lobe (MTL) epilepsy typically undergo inpatient video–electroencephalography (EEG) monitoring with scalp and/or intracranial electrodes for 1 to 2 weeks to localize and lateralize the seizure focus or foci. Chronic ambulatory electrocorticography (ECoG) in patients with MTL epilepsy may provide additional information about seizure lateralization. This analysis describes data obtained from chronic ambulatory ECoG in patients with suspected bilateral MTL epilepsy in order to assess the time required to determine the seizure lateralization and whether this information could influence treatment decisions. Methods Ambulatory ECoG was reviewed in patients with suspected bilateral MTL epilepsy who were among a larger cohort with intractable epilepsy participating in a randomized controlled trial of responsive neurostimulation. Subjects were implanted with bilateral MTL leads and a cranially implanted neurostimulator programmed to detect abnormal interictal and ictal ECoG activity. ECoG data stored by the neurostimulator were reviewed to determine the lateralization of electrographic seizures and the interval of time until independent bilateral MTL electrographic seizures were recorded. Results Eighty-two subjects were implanted with bilateral MTL leads and followed for 4.7 years on average (median 4.9 years). Independent bilateral MTL electrographic seizures were recorded in 84%. The average time to record bilateral electrographic seizures in the ambulatory setting was 41.6 days (median 13 days, range 0–376 days). Sixteen percent had only unilateral electrographic seizures after an average of 4.6 years of recording. Significance About one third of the subjects implanted with bilateral MTL electrodes required \u3e1 month of chronic ambulatory ECoG before the first contralateral MTL electrographic seizure was recorded. Some patients with suspected bilateral MTL seizures had only unilateral electrographic seizures. Chronic ambulatory ECoG in patients with suspected bilateral MTL seizures provides data in a naturalistic setting, may complement data from inpatient video-EEG monitoring, and can contribute to treatment decisions. Key Points Ambulatory electrocorticograms were obtained in patients implanted with a responsive neurostimulator and bilateral mesial temporal intracranial electrodes. In patients with bilateral seizures, the average time to record bilateral electrographic seizures in the ambulatory setting was 41.6 days (median 13, range 0–376). Some patients suspected to have bilateral MTL seizures after standard diagnostic localization evaluations had only unilateral electrographic seizures. Chronic ambulatory ECoG samples provide naturalistic data that complement inpatient monitoring, and may contribute information that affects treatment decisions

Long-term treatment with responsive brain stimulation in adults with refractory partial seizures.

OBJECTIVE: The long-term efficacy and safety of responsive direct neurostimulation was assessed in adults with medically refractory partial onset seizures. METHODS: All participants were treated with a cranially implanted responsive neurostimulator that delivers stimulation to 1 or 2 seizure foci via chronically implanted electrodes when specific electrocorticographic patterns are detected (RNS System). Participants had completed a 2-year primarily open-label safety study (n = 65) or a 2-year randomized blinded controlled safety and efficacy study (n = 191); 230 participants transitioned into an ongoing 7-year study to assess safety and efficacy. RESULTS: The average participant was 34 (±11.4) years old with epilepsy for 19.6 (±11.4) years. The median preimplant frequency of disabling partial or generalized tonic-clonic seizures was 10.2 seizures a month. The median percent seizure reduction in the randomized blinded controlled trial was 44% at 1 year and 53% at 2 years (p \u3c 0.0001, generalized estimating equation) and ranged from 48% to 66% over postimplant years 3 through 6 in the long-term study. Improvements in quality of life were maintained (p \u3c 0.05). The most common serious device-related adverse events over the mean 5.4 years of follow-up were implant site infection (9.0%) involving soft tissue and neurostimulator explantation (4.7%). CONCLUSIONS: The RNS System is the first direct brain responsive neurostimulator. Acute and sustained efficacy and safety were demonstrated in adults with medically refractory partial onset seizures arising from 1 or 2 foci over a mean follow-up of 5.4 years. This experience supports the RNS System as a treatment option for refractory partial seizures. CLASSIFICATION OF EVIDENCE: This study provides Class IV evidence that for adults with medically refractory partial onset seizures, responsive direct cortical stimulation reduces seizures and improves quality of life over a mean follow-up of 5.4 years

Alternative pre-analytic sample handling techniques for glucose measurement in the absence of fluoride tubes in low resource settings.

INTRODUCTION: Sodium fluoride (NaF) tubes are the recommended tubes for glucose measurements, but these are expensive, have limited number of uses, and are not always available in low resource settings. Alternative sample handling techniques are thus needed. We compared glucose stability in samples collected in various tubes exposed to different pre-analytical conditions in Uganda. METHODS: Random (non-fasted) blood samples were drawn from nine healthy participants into NaF, Ethylenediaminetetraacetic acid (EDTA), and plain serum tubes. The samples were kept un-centrifuged or centrifuged with plasma or serum pipetted into aliquots, placed in cool box with ice or at room temperature and were stored in a permanent freezer after 0, 2, 6, 12 and 24 hours post blood draw before glucose analysis. RESULTS: Rapid decline in glucose concentrations was observed when compared to baseline in serum (declined to 64%) and EDTA-plasma (declined to 77%) after 6 hours when samples were un-centrifuged at room temperature whilst NaF-plasma was stable after 24 hours in the same condition. Un-centrifuged EDTA-plasma kept on ice was stable for up to 6 hours but serum was not stable (degraded to 92%) in the same conditions. Early centrifugation prevented glucose decline even at room temperature regardless of the primary tube used with serum, EDTA-plasma and NaF-plasma after 24 hours. CONCLUSION: In low resource settings we recommend use of EDTA tubes placed in cool box with ice and analysed within 6 hours as an alternative to NaF tubes. Alternatively, immediate separation of blood with manual hand centrifuges will allow any tube to be used even in remote settings with no electricity

Lateralization of mesial temporal lobe epilepsy with chronic ambulatory electrocorticography

OBJECTIVE: Patients with suspected mesial temporal lobe (MTL) epilepsy typically undergo inpatient video-electroencephalography (EEG) monitoring with scalp and/or intracranial electrodes for 1 to 2 weeks to localize and lateralize the seizure focus or foci. Chronic ambulatory electrocorticography (ECoG) in patients with MTL epilepsy may provide additional information about seizure lateralization. This analysis describes data obtained from chronic ambulatory ECoG in patients with suspected bilateral MTL epilepsy in order to assess the time required to determine the seizure lateralization and whether this information could influence treatment decisions. METHODS: Ambulatory ECoG was reviewed in patients with suspected bilateral MTL epilepsy who were among a larger cohort with intractable epilepsy participating in a randomized controlled trial of responsive neurostimulation. Subjects were implanted with bilateral MTL leads and a cranially implanted neurostimulator programmed to detect abnormal interictal and ictal ECoG activity. ECoG data stored by the neurostimulator were reviewed to determine the lateralization of electrographic seizures and the interval of time until independent bilateral MTL electrographic seizures were recorded. RESULTS: Eighty-two subjects were implanted with bilateral MTL leads and followed for 4.7 years on average (median 4.9 years). Independent bilateral MTL electrographic seizures were recorded in 84%. The average time to record bilateral electrographic seizures in the ambulatory setting was 41.6 days (median 13 days, range 0-376 days). Sixteen percent had only unilateral electrographic seizures after an average of 4.6 years of recording. SIGNIFICANCE: About one third of the subjects implanted with bilateral MTL electrodes required >1 month of chronic ambulatory ECoG before the first contralateral MTL electrographic seizure was recorded. Some patients with suspected bilateral MTL seizures had only unilateral electrographic seizures. Chronic ambulatory ECoG in patients with suspected bilateral MTL seizures provides data in a naturalistic setting, may complement data from inpatient video-EEG monitoring, and can contribute to treatment decisions