AVANCES EN EL ESTUDIO DE LA PATOGÉNESIS Y PREVENCIÓN DE LA ENTEROTOXEMIA DE LAS ALPACAS.

The results of our recent research work on enterotoxemia in Peruvian alpacas are presented. Microbiological and molecular analyses found that the majority of the isolates corresponded to Clostridium perfringens and contained the cpa coding gene for α toxin (A genotype) while 0.4% contained both the cpa and cpb genes of the α and β toxins (C genotype). A parallel study revealed that 8.5% of the genotype A isolates also had cpb2, but the cpe (enterotoxin) gene was absent in all cases. These results highly suggest that the exotoxins secreted by C. perfringens are the virulent factors in enterotoxemia, rather than the endogenous enterotoxin. Additionally, an histopathological study of intestinal samples from fatal cases showed that 30.6% had abundant immature structures of Eimeria macusaniensis affecting deep mucosa and cryptic gland epithelia, primarily in the jejune and ileum, suggesting that eimeriosis is likely a triggering or predisposing factor for the development of enterotoxemia. The microbiological studies allowed the design and progressive improvement of an inactivated enterotoxemia vaccine containing primarily the bacterial component plus exotoxins of types A, Aβ2 and C isolated from natural fatal cases of the disease. During six years of field tests in southern Peru, the vaccine has steadily reduced specific neonatal mortality rates due to enterotoxemia from 19.5% (2000, without vaccine) to less than 5% in 2006.Se revisan las investigaciones recientes realizadas por nuestro grupo de investigadores sobre enterotoxemia de las alpacas en el Perú. Estudios microbiológicos y moleculares demostraron que la mayoría de las cepas aisladas fueron de Clostridium perfringens y estas contienen únicamente el gen cpa de la toxina α (C. perfringens genotipo A) y solamente el 0.4% tienen genes cpa y cpb de las toxinas α y β (genotipo C). En análisis paralelo, se encontró que el 8.5% de los genotipos A contenían, adicionalmente, el gen cpb2, pero ninguna cepa tenía el gen cpe de la enterotoxina. Estos resultados evidencian que las exotoxinas secretadas, y no las endotoxinas (cpe), serían los probables factores de virulencia clostridiales en la enterotoxemia de la alpaca. Adicionalmente, en el análisis histopatológico de intestinos infectados, el 30.6% de las muestras presentó abundantes estructuras parasitarias inmaduras correspondientes a Eimeria macusaniensis, afectando la mucosa y epitelio de las glándulas crípticas intestinales, sugiriendo a las infecciones coccidiales como uno de los posibles factores desencadenantes o predisponentes de la enterotoxemia. Estos resultados microbiológicos permitieron diseñar, preparar y mejorar una vacuna convencional inactivada que contiene, mayoritariamente, componentes bacterianos y exotoxinas A, Aβ2 y C aislados de casos fatales de la enfermedad. Desde su introducción en una empresa alpaquera del sur peruano en 2001, la vacuna ha logrado reducir progresivamente los índices de mortalidad por enterotoxemia de 19.5% (2000, sin vacuna) hasta alcanzar tasas menores al 5% en 2006

Phase I clinical trial in healthy adults of a nasal vaccine candidate containing recombinant hepatitis B surface and core antigens

SummaryBackgroundThe nasal vaccine candidate (NASVAC), comprising hepatitis B virus (HBV) surface (HBsAg) and core antigens (HBcAg), has been shown to be highly immunogenic in animal models.MethodsA phase I double-blinded, placebo-controlled randomized clinical trial was carried out in 19 healthy male adults with no serologic markers of immunity/infection to HBV. This study was aimed at exploring the safety and immunogenic profile of nasal co-administration of both HBV recombinant antigens. The trial was performed according to Good Clinical Practice guidelines. Participants ranged in age from 18 to 45 years and were randomly allocated to receive a mixture of 50μg HBsAg and 50μg HBcAg or 0.9% physiologic saline solution, as a placebo, via nasal spray in a five-dose schedule at 0, 7, 15, 30, and 60 days. A total volume of 0.5ml was administered in two dosages of 125μl per nostril. Adverse events were actively recorded 1h, 6h, 12h, 24h, 48h, 72h, 7 days and 30 days after each dose. Anti-HBs and anti-HBc titers were evaluated using corresponding ELISA kits at days 30 and 90.ResultsThe vaccine candidate was safe and well tolerated. Adverse reactions included sneezing (34.1%), rhinorrhea (12.2%), nasal stuffiness (9.8%), palate itching (9.8%), headache (9.8%), and general malaise (7.3%). These reactions were all self-limiting and mild in intensity. No severe or unexpected events were recorded during the trial. The vaccine elicited anti-HBc seroconversion in 100% of subjects as early as day 30 of the immunization schedule, while a seroprotective anti-HBs titer (≥10IU/l) was at a maximum at day 90 (75%). All subjects in the placebo group remained seronegative during the trial.ConclusionThe HBsAg–HBcAg vaccine candidate was safe, well tolerated and immunogenic in this phase I study in healthy adults. To our knowledge, this is the first demonstration of safety and immunogenicity for a nasal vaccine candidate comprising HBV antigens

Genetic Structure Among 50 Species of the Northeastern Pacific Rocky Intertidal Community

Comparing many species' population genetic patterns across the same seascape can identify species with different levels of structure, and suggest hypotheses about the processes that cause such variation for species in the same ecosystem. This comparative approach helps focus on geographic barriers and selective or demographic processes that define genetic connectivity on an ecosystem scale, the understanding of which is particularly important for large-scale management efforts. Moreover, a multispecies dataset has great statistical advantages over single-species studies, lending explanatory power in an effort to uncover the mechanisms driving population structure. Here, we analyze a 50-species dataset of Pacific nearshore invertebrates with the aim of discovering the most influential structuring factors along the Pacific coast of North America. We collected cytochrome c oxidase I (COI) mtDNA data from populations of 34 species of marine invertebrates sampled coarsely at four coastal locations in California, Oregon, and Alaska, and added published data from 16 additional species. All nine species with non-pelagic development have strong genetic structure. For the 41 species with pelagic development, 13 show significant genetic differentiation, nine of which show striking FST levels of 0.1–0.6. Finer scale geographic investigations show unexpected regional patterns of genetic change near Cape Mendocino in northern California for five of the six species tested. The region between Oregon and Alaska is a second focus of intraspecific genetic change, showing differentiation in half the species tested. Across regions, strong genetic subdivision occurs more often than expected in mid-to-high intertidal species, a result that may reflect reduced gene flow due to natural selection along coastal environmental gradients. Finally, the results highlight the importance of making primary research accessible to policymakers, as unexpected barriers to marine dispersal break the coast into separate demographic zones that may require their own management plans

Multi-ancestry genome-wide association meta-analysis of Parkinson?s disease

Although over 90 independent risk variants have been identified for Parkinson’s disease using genome-wide association studies, most studies have been performed in just one population at a time. Here we performed a large-scale multi-ancestry meta-analysis of Parkinson’s disease with 49,049 cases, 18,785 proxy cases and 2,458,063 controls including individuals of European, East Asian, Latin American and African ancestry. In a meta-analysis, we identified 78 independent genome-wide significant loci, including 12 potentially novel loci (MTF2, PIK3CA, ADD1, SYBU, IRS2, USP8, PIGL, FASN, MYLK2, USP25, EP300 and PPP6R2) and fine-mapped 6 putative causal variants at 6 known PD loci. By combining our results with publicly available eQTL data, we identified 25 putative risk genes in these novel loci whose expression is associated with PD risk. This work lays the groundwork for future efforts aimed at identifying PD loci in non-European populations