Phytosociological analysis of the mesophilic forest of the San Pedro volcano (Guatemala).

From a standpoint of phytosociological research, little is known about the phytocoenosis found on the volcanoes of Central America. This paper analyses the distribution of the vegetation on the volcano of San Pedro in terms of its species-richness, composition, structure and abundance, and the possible relationships between these components and the changes in elevation and orientation that occur there. We divided the study area into three altitudinal belts between 2,400 and 3,020 m a.s.l. where carried out 36 inventories, each one in an area of 0.1 ha. We then applied multivariate analysis to classify and order the data in the matrix obtained from the frequency of the sampled plants. Our results lead us to propose two mixed cloud-forest associations within the class Alnetea acuminatae. The first, Saurauio oreophilae-Alnetum acuminatae ass. nova, is found on the more humid western side, while the second, Adianto andicolae-Quercetum peduncularis ass. nova, appears in sunnier and less shady sites, mainly on the east face. As part of this latter association, we also identified the new subassociation festucetosum amplissimae subass. nova. These syntaxa are part of the alliance Oreopanacion xalapensis all. nova, which we have created to embrace the mesophytic montane forests dominated by broad-leaved species.

Impacts of land management and climate change in a developing and socioenvironmental challenging transboundary region.

Land-use/cover change is the major cause of terrestrial ecosystem degradation. However, its impacts will be exacerbated due to climate change and population growth, driving agricultural expansion because of higher demand of food and lower agricultural yields in some tropical areas. International strategies aimed to mitigate impacts of climate change and land use-cover change are challenging in developing regions. This study aims to evaluate alternatives to minimize the impacts of these threats under socioeconomic trajectories, in one of the biologically richest regions in Guatemala and Mexico. This study is located at the Usumacinta watershed, a transboundary region that shares a common history, with similar biophysical properties and economic constraints which have led to large land use/cover changes. To understand the impacts on deforestation and carbon emissions of different land-management practices, we developed three scenarios (1): business as usual (BAU), (2) a reducing emissions scenario aimed to reduce deforestation and degradation (REDD+), and (3) zero-deforestation from 2030 onwards based on the international commitments. Our results suggest that by 2050, natural land cover might reduce 22.3 and 12.2% of its extent under the BAU and REDD + scenarios, respectively in comparison with 2012. However, the zero-deforestation scenario shows that by 2050, it would be possible to avoid losing 22.4% of the forested watershed (1.7 million ha) and recover 5.9% (0.4 million hectares) of it. In terms of carbon sequestration, REDD + projects can reduce the carbon losses in natural vegetation, but a zero-deforestation policy can double the carbon sequestration produced by REDD + projects only. This study shows that to reduce the pressures on ecosystems, particularly in regions highly marginalized with significant migration, it is necessary to implement transboundary land-management policies that also integrate poverty alleviation strategies.

50 Aniversario de la Escuela de Biología

Editorial. 50 Aniversario de la Escuela de Biología La historia de la Escuela de Biología de la Universidad de San Carlos de Guatemala inicia con la inspiración de un hombre visionario, quien desde el año 1968, siendo director del departamento de Biología de la Facultad de Ciencias Químicas y Farmacia, elaboró una propuesta para su creación. En su momento, esta no fue aprobada, por razones de presupuesto, administrativas y de otra índole, pero este visionario no dio marcha atrás en su lucha por sentar las bases para una formación sólida en el campo de la Biología, tan necesaria en nuestro país.

Estimation of Blockage Position, Geometry, and Solidity in Molten Salt Pipelines.

In solar thermal plants, the use of molten salt as a heat transfer fluid is an advantageous alternative, although it has some disadvantages such as the formation of salt plugs in the pipes due to possible stratification of the salt or its solidification. The aim of this study was to implement an electromagnetic acoustic transducer (EMAT) not only capable of identifying the position of the plug, but also of determining whether the plug blocks the entire conductive surface or, on the contrary, is partial, allowing the fluid to pass through a smaller section. The proposed transducer is intended to be minimally invasive, allowing it to be used in the same way as a temperature probe. To do so, it creates torsional waves in the pipe, which are then used for a combination of measurements: pulse-echo and attenuation of the acoustic waves. Two materials with different densities (silicone and cement) were used in the tests carried out, which made it possible to check that for a given size of blockage, it is possible to identify the type of material from which it is formed.

Real-time Automatic Calculation of Euro Coins and Banknotes in a Cash Drawer.

A very interesting and useful complement to classical cash-registers is presented in this paper, coming up with a real-time auto-counting solution for the money inside a cash drawer. The system allows knowing not only the total amount of money but also how many coins and banknotes there are of each value. The embedded solution developed has been intended to become a low-cost solution, allowing better control over the money and helping both owners and workers in the establishments. By using this system, new utilities including automatic final balancing, instant error handling when making operations, and the lack of certain types of banknotes or coins inside the drawer or the excess of some in a certain compartment, could be implemented. Coins-counting solution is based on their weight, and small individual scales made by load cells have been integrated in each coin compartment. With respect to the banknotes, an innovative alternative based on the electrical properties of capacitors is presented. Additionally, considering the relevance of interoperability in today's systems, a Bluetooth module has been integrated into the system, allowing for data to be accessed remotely from any smartphone, tablet or computer within the range of the module. In this work, an Android application to both control and interact with the system has also been designed.

Magnetostrictive Sensor for Blockage Detection in Pipes Subjected to High Temperatures.

The use of solar thermal power plants is considered a cost-effective alternative to produce renewable energy. Unlike other energy installations, in this type of plants the transfer and storage of energy has been solved by using molten salts. These salts run between two tanks through the steam generation system that feeds the turbine. Although the use of salts as a heat transfer fluid is considered an adequate solution, they are not without problems. One of them is the formation of blockages in the pipes due to a partial solidification of the salt, which leads to the shutdown of the installation, with the consequent economic losses. Fast location of these blockages in a minimally intrusive way is the objective pursued in this work. The method to achieve this is based on the use of a new magnetostrictive sensor that simplifies previous designs.

Calidad de vida en personas con disartria / Quality of life in people with dysarthria

Introducción: La disartria corresponde a un trastorno adquirido del habla de origen neurológico. Habitualmente, la evaluación se centra en describir los procesos motores del habla afectados, las características perceptuales y determinar el grado de severidad a través de la inteligibilidad del habla. Pocas veces se explora el impacto de este trastorno sobre la calidad de vida de la persona. Método: Se realizó un estudio cuantitativo, no experimental, transversal, descriptivo y correlacional. Se evaluaron 21 personas con disartria (51.04 ± 13.06 años, 13 hombres) con el protocolo de evaluación de habla para pacientes disártricos y el cuestionario autoadministrado de calidad de vida en hablantes disártricos (QOL-Dys). Resultados: Las personas con disartria ven alterada su calidad de vida. Hay una correlación significativa con el grado de severidad de la disartria (r = -.5, p =.02). La inteligibilidad predice de manera significativa el puntaje en el cuestionario de calidad de vida total (R2 =.2, p =.04). El puntaje más bajo se presenta en la percepción de la reacción de los otros (1.66 ± 12.93), y el más alto en enfrentarse a situaciones difíciles (24.38 ± 9.12). Conclusión: La disartria afecta la calidad de vida de las personas. Se recomienda su evaluación para mejorar la intervención en estas personas

Introduction: Dysarthria is an acquired motor speech disorder of neurological origin. Usually assessment focuses on describing the affected motor processes of speech, perceptual characteristics and determining the degree of severity through speech intelligibility, but rarely explores the impact it has on the quality of life of the person. Method: A quantitative, non-experimental, cross-sectional, descriptive and correlational study was performed. Twenty-one patients with dysarthria (51.04 ± 13.06 years, 13 men) were evaluated with the speech assessment protocol for dysarthric patients and the self-administered quality of life questionnaire for dysarthric speakers (QOL-Dys). Results: The quality of life of people with dysarthria is affected (QOL), which correlates significantly with the degree of severity of the dysarthria (r = -.5, p = .02). Intelligibility significantly predicts the score of the total quality of life questionnaire (R2 =.2, p = .04). The lowest score occurred in the perception of the reaction of the others (16.66 ± 12.93), and the highest in dealing with difficult situations (24.38 ± 9.12). Conclusion: Quality of life is affected in people with dysarthria, its assessment is recommended to improve intervention in these people

Genetic characterization of South American infectious bursal disease virus reveals the existence of a distinct worldwide-spread genetic lineage.

Infectious bursal disease virus (IBDV) is one of the most concerning health problems for world poultry production. IBDVs comprise four well-defined evolutionary lineages known as classic (c), classic attenuated (ca), variant (va) and very virulent (vv) strains. Here, we characterized IBDVs from South America by the genetic analysis of both segments of the viral genome. Viruses belonging to c, ca and vv strains were unambiguously classified by the presence of molecular markers and phylogenetic analysis of the hypervariable region of the vp2 gene. Notably, the majority of the characterized viruses (9 out of 15) could not be accurately assigned to any of the previously described strains and were then denoted as distinct (d) IBDVs. These dIBDVs constitute an independent evolutionary lineage that also comprises field IBDVs from America, Europe and Asia. The hypervariable VP2 sequence of dIBDVs has a unique and conserved molecular signature (272T, 289P, 290I and 296F) that is a diagnostic character for classification. A discriminant analysis of principal components (DAPC) also identified the dIBDVs as a cluster of genetically related viruses separated from the typical strains. DAPC and genetic distance estimation indicated that the dIBDVs are one of the most genetically divergent IBDV lineages. The vp1 gene of the dIBDVs has non-vvIBDV markers and unique nucleotide and amino acid features that support their divergence in both genomic segments. The present study suggests that the dIBDVs comprise a neglected, highly divergent lineage that has been circulating in world poultry production since the early time of IBDV emergence.

Phylodynamic analysis of avian infectious bronchitis virus in South America.

Infectious bronchitis virus (IBV) is a coronavirus of chickens that causes great economic losses to the global poultry industry. The present study focuses on South American IBVs and their genetic relationships with global strains. We obtained full-length sequences of the S1 coding region and N gene of IBV field isolates from Uruguay and Argentina, and performed Phylodynamic analysis to characterize the strains and estimate the time of the most recent common ancestor. We identified two major South American genotypes, which were here denoted South America I (SAI) and Asia/South America II (A/SAII). The SAI genotype is an exclusive South American lineage that emerged in the 1960s. The A/SAII genotype may have emerged in Asia in approximately 1995 before being introduced into South America. Both SAI and A/SAII genotype strains clearly differ from the Massachusetts strains that are included in the vaccine formulations being used in most South American countries.

Development of a wireless sensor network for individual monitoring of panels in a photovoltaic plant.

With photovoltaic (PV) systems proliferating in the last few years due to the high prices of fossil fuels and pollution issues, among others, it is extremely important to monitor the efficiency of these plants and optimize the energy production process. This will also result in improvements related to the maintenance and security of the installation. In order to do so, the main parameters in the plant must be continuously monitored so that the appropriate actions can be carried out. This monitoring should not only be carried out at a global level, but also at panel-level, so that a better understanding of what is actually happening in the PV plant can be obtained. This paper presents a system based on a wireless sensor network (WSN) that includes all the components required for such monitoring as well as a power supply obtaining the energy required by the sensors from the photovoltaic panels. The system proposed succeeds in identifying all the nodes in the network and provides real-time monitoring while tracking efficiency, features, failures and weaknesses from a single cell up to the whole infrastructure. Thus, the decision-making process is simplified, which contributes to reducing failures, wastes and, consequently, costs.

Do shade-grown coffee plantations pose a disease risk for wild birds?

Shade-grown coffee plantations are often promoted as a conservation strategy for wild birds. However, these agro-ecosystems are actively managed for food production, which may alter bird behaviors or interactions that could change bird health, compared to natural forest. To examine whether there is a difference between the health parameters of wild birds inhabiting shade-grown coffee plantations and natural forest, we evaluated birds in Costa Rica for (1) their general body condition, (2) antibodies to pathogens, (paramyxovirus and Mycoplasma spp.), and (3) the prevalence and diversity of endo-, ecto-, and hemoparasites. We measured exposure to Mycoplasma spp. and paramyxovirus because these are pathogens that could have been introduced with domestic poultry, one mechanism by which these landscapes could be detrimental to wild birds. We captured 1,561 birds representing 75 species. Although seasonal factors influenced body condition, we did not find bird general body condition to be different. A total of 556 birds of 31 species were tested for antibodies against paramyxovirus-1. Of these, five birds tested positive, four of which were from shade coffee. Out of 461 other tests for pathogens (for antibodies and nucleotide detection), none were positive. Pterolichus obtusus, the feather mite of chickens, was found on 15 birds representing two species and all were from shade-coffee plantations. Larvated eggs of Syngamus trachea, a nematode typically associated with chickens, were found in four birds captured in shade coffee and one captured in forest. For hemoparasites, a total of 1,121 blood smears from 68 bird species were examined, and only one species showed a higher prevalence of infection in shade coffee. Our results indicate that shade-coffee plantations do not pose a significant health risk to forest birds, but at least two groups of pathogens may deserve further attention: Haemoproteus spp. and the diversity and identity of endoparasites.

Development and validation of a TaqMan-MGB real-time RT-PCR assay for simultaneous detection and characterization of infectious bursal disease virus.

Rapid and reliable detection and classification of infectious bursal disease viruses (IBDVs) is of crucial importance for disease surveillance and control. This study presents the development and validation of a real-time RT-PCR assay to detect and discriminate very virulent (vv) from non-vv (classic and variant) IBDV strains. The assay uses two fluorogenic, minor groove-binding (MGB) TaqMan probes targeted to a single nucleotide polymorphism (SNP) embedded in a highly conserved genomic region. The analytical sensitivity of the assay was determined using serial dilutions of in vitro-transcribed RNA. The assay demonstrated a wide dynamic range between 10(2) and 10(8) standard RNA copies per reaction. Good reproducibility was also detected, with intra- and inter-assay coefficients of variation ranging from 0.13% to 2.23% and 0.26% to 1.92%, respectively. The assay detected successfully all the assessed vv, classical, and variant field and vaccine strains and correctly discriminated all vvIBDV strains from non-vvIBDV strains. Other common avian RNA viruses tested negative, indicating high specificity of the assay. The high sensitivity, rapidity, reproducibility, and specificity of the real-time RT-PCR assay make this method suitable for general and genotype-specific detection and quantitation.

Novel multiplex RT-PCR/RFLP diagnostic test to differentiate low- from high-pathogenic strains and to detect reassortant infectious bursal disease virus.

Three types of infectious bursal disease virus (IBDV) strains are currently circulating worldwide: the low-pathogenic classic and variant strains and the high-pathogenic very virulent strains. There are also natural reassortant viruses that combine genomic segments A and B from different strains and exhibit particular pathogenic characteristics. Detection and characterization of the different IBDVs is extremely critical for improving disease control and performing epidemiologic studies. Here, we present a novel detection and genotyping method based on the simultaneous characterization of both IBDV genomic segments followed by a simple restriction fragment length polymorphism (RFLP) assay. This single restriction enzyme, multiplex reverse transcriptase-PCR/RFLP diagnostic test not only distinguished typical high-pathogenic from low-pathogenic strains but also detected natural reassortant IBDV. The test was based on the detection of single nucleotide polymorphisms (SNP), in both segments, which were strongly linked to the pathogenic phenotype. These SNPs are embedded in highly conserved genomic regions and can be identified with TfiI endonuclease. The application of this methodology in field samples confirmed that the assay is fast, specific, and may be easily adopted by any molecular diagnostic laboratory as an economical and routine method.

Sequence variability and evolution of the terminal overlapping VP5 gene of the infectious bursal disease virus.

The infectious bursal disease virus (IBDV; Birnaviridae family) constitutes one of the main threats to the poultry industry worldwide. Most of the progress in the molecular epidemiology of this virus has been achieved through the study of the coding region of the capsid protein VP2. Little research has been done regarding the molecular evolution and the epidemiological implications of genetic variability of other IBDV genome regions. In this article, the gene that codes the non-structural protein VP5 was analyzed. Although this protein is not essential for the virus replication, recent evidence indicates that it could be related to the virulent phenotype and the adaptive capacity of the virus. The VP5 gene is also of evolutionary interest because it has an open reading frame that terminally overlaps with the pVP2-VP4-VP3 polyprotein coding region. In the first part of this study, the full VP5 gene of a South American strain was characterized. The results revealed that the VP5 gene of Uruguayan hypervirulent IBDV strains (vvIBDV) lacks the alternative AUG start codon characteristic of the vvIBDV strains that have been described to date. Instead, as occurs in classic and variant strains, this VP5 gene has an AUG start site located four codons downstream and, consequently, it codes for a 145 amino acid long protein rather than the putative 149 amino acid long protein of other vvIBDV. In spite of this, these viruses conserved the VP5 and VP2 amino acid signature of the hypervirulent strains and clustered with reference vvIBDV sequences. This finding may represent evidence that the VP5 gene could be evolving by changing the translation initiation site. In the second part of this study, an evolutionary analysis including the sequences reported in this study together with most of VP5 sequences available in the GenBank, showed the existence of a complex system of selective pressures controlling the evolution of the VP5 gene. Using the dN/dS index, we found a strong purifying selection exerted on the 5' terminal overlapping region of VP2 that would be constraining the evolution of VP5. These results reinforce the hypothesis that the VP5 gene was originated late in the IBDV evolution by a mechanism of genetic overprinting. The results described in this study provided new information about the dynamics of the IBDV genome and revealed some of the mechanisms at play in the evolution of this virus. Since VP5 seems to be related to viral pathogenicity, this evolutionary information might be useful to highlight the impact of the genetic variation of this protein on the epidemiology of IBDV.

Eficacia de un herpesvirus de pavo recombinante expresando la proteína VP2 del virus de la enfermedad de Gumboro ante un desafío experimental / Efficacy of a Recombinant Turkey Herpesvirus Expressing the Viral Protein 2 of the Gumboro Disease Virus Against an Experimental Challenge

La vacunación temprana contra el virus de la enfermedad infecciosa de la bolsa (por sus siglas en inglés IBDV) es una práctica muy común; sin embargo, el uso de vacunas de baja atenuación puede comprometer la integridad de la bolsa de Fabricio en aves jóvenes generando inmunosupresión y el fracaso de los planes de vacunación. Una alternativa es la utilización de vectores virales para la expresión transgénica de proteínas inmunogénicas que pueden proporcionar protección adecuada sin el potencial daño a la bolsa. El objetivo del presente trabajo fue evaluar la protección contra un desafío experimental con cepas clásicas conferida por la vacunación al día de edad con VAXXITEK®, un herpesvirus de pavo (por sus siglas en inglés HVT) expresando la proteína inmunogénica VP2 de una cepa clásica del IBDV. Aves libres de patógenos específicos fueron vacunadas al día de edad por la vía subcutánea y luego desafiadas a los 18 ó 28 días de edad con la cepa STC del virus de la enfermedad de Gumboro. El criterio de protección incluyó signos clínicos, índice peso bolsa/peso corporal y la histopatología de la bolsa. En las aves vacunadas con VAXXITEK®, no se observaron signos clínicos o lesiones asociadas al desafío con la cepa STC, ni en el desafío temprano ni en el tardío. El índice bursal resultó significativamente menor en las aves no vacunadas que fueron desafiadas. Estos resultados indican que una dosis de la vacuna HVT-IBDV recombinante protege a las aves contra un desafío con cepas clásicas.

Early vaccination against infectious bursal disease virus (IBDV) is a common practice; however, the use of live attenuated vaccines may sometimes compromise the bursal integrity in young birds generating immunosupression and failures in vaccination programs. An alternative is the use of viral vectors for transgenic expression of immunogenic proteins that can provide adequate protection without the potential bursal damage. The objective of this work was to assess the protection against a classical strain challenge conferred by day-one vaccination using VAXXITEK®, a recombinant herpesvirus of turkey expressing the immunogenic viral protein 2 from a classical IBDV. Specific pathogen free (SPF) one-day old birds were vaccinated by the subcutaneous route and challenged with the STC IBDV strain at 18 or 28 days of age. The protection criteria included: clinical signs, bursa/bodyweight ratio and bursal histopathology. No clinical signs or STC challenge related bursal lesions were observed in the VAXXITEK® vaccinated birds at both early and late challenge. The bursal index was significantly lower in the unvaccinated challenged birds. These results indicate that single dose recombinant HVT-IBDV vaccination protects chickens against a classical strain challenge.

Protection conferred by coarse spray vaccination against challenge with infectious bursal disease virus in commercial broilers.

The efficacy of coarse spray vaccination against pathogenic infectious bursal disease virus (IBDV) in commercial broilers was evaluated. Different coarse spray vaccination schedules using a commercial 2512 strain vaccine were compared with single or double drinking water application at 1 and/or 10 days of age. At 29 days of age, the chickens were challenged with the virulent Edgar strain of IBDV. Seven days postchallenge, severe gross bursal atrophy was observed in the unvaccinated-challenged birds. After challenge and regardless of the method of vaccination used, moderate-to-severe lymphoid depletion was observed, indicating challenge virus replication, later confirmed by reverse transcriptase-polymerase chain reaction and restriction fragment length polymorphism analysis. Coarse spray and drinking water vaccination induced protection against body weight loss. Significant differences (P < 0.05) were observed between the unvaccinated-challenged group (1483 g) and the birds vaccinated at 10 days of age by coarse spray (1812 g). The coarse spray vaccination also induced protection against challenge-induced gross bursal atrophy, as determined by bursal index values. After challenge, significant bursal atrophy was observed in the birds orally vaccinated at 1 day (0.61), 10 days (0.66), and 1 and 10 days (0.63) as well as the unvaccinated-challenged birds (0.62), but not in the coarse-spray-vaccinated groups that exhibited bursal indexes above 0.70 and did not differ from the unvaccinated-unchallenged control group. These results suggest that coarse spray vaccination can be considered as another tool to control IBDV in the field.

The VG/GA strain of Newcastle disease virus: mucosal immunity, protection against lethal challenge and molecular analysis.

The Villegas-Glisson/University of Georgia (VG/GA) strain of Newcastle disease virus (NDV) isolated from the intestine of healthy turkeys has been proposed to replicate in the respiratory and intestinal tract of chickens. In the present study, the virus distribution, the mucosal and systemic immune response, the efficacy against lethal challenge and the full genome sequence of the VG/GA strain were compared with the La Sota strain of NDV. The VG/GA strain was detected at different time points in the respiratory and intestinal tract of chickens with a preferential tropism for the latter. Both the VG/GA and La Sota strains induced NDV-specific immunoglobulin A (IgA) at the upper respiratory tract. IgA levels were higher in the trachea for the La Sota strain, while they were higher in the bile and intestine for the VG/GA strain. Positive correlation between virus distribution of the viruses and IgA production was observed. Despite the presence of the maternal antibodies in broilers, early vaccination with the VG/GA strain afforded 95% to 100% protection against lethal challenge, equivalent to the protection conferred by the La Sota strain. Full genome sequence analysis classified the VG/GA strain within class II, genotype II viruses, which also include most of the respirotropic vaccine strains. Differences with the La Sota strain at the nucleotide and amino acid levels that may explain the differential phenotype of the VG/GA were observed; however, verification of the significance of those changes is required. Taken together, these results validate field observations on the efficacy of VG/GA vaccination and demonstrated the unique characteristics of the strain.

Genomic comparison of the complete coding and intergenic regions of the VG/GA Newcastle disease virus and its respirotropic clone 5.

The complete genome of the Villegas-Glisson/University of Georgia (VG/GA) strain of Newcastle disease virus (NDV) and that of a plaque purified clone (clone 5) exhibiting a respiratory phenotype were sequenced and analyzed. The VG/GA strain, isolated from the intestine of healthy turkeys, replicates in the respiratory and intestinal tract of chickens. It is used worldwide as a vaccine strain and its tissue tropism is extremely important for protection against velogenic viscerotropic NDV which targets both intestinal and respiratory epithelia, inducing severe gross and microscopic damage. The clone 5, a plaque purified clone from the VG/GA strain, cannot be recovered from the intestine of infected birds, suggesting a respirotropic nature. A modified primer sequence-independent amplification method was used to sequence the complete coding regions of both viruses and to assess phylogenetic relationships and genomic basis for phenotype differences. The phylogenetic analysis grouped the VG/GA strain and the clone 5 within class II, genotype II viruses and showed that they are greater than 99.9% identical with only 5 nucleotides differences. Both are closely related to classic vaccine strains, such as LaSota and B1. Only 3 amino acid differences at the fusion protein differentiated the VG/GA strain from the clone 5. These differences may explain the differential phenotype observed in the VG/GA strain and are discussed.

Backyard chicken flocks pose a disease risk for neotropic birds in Costa Rica.

Pathogens of free-ranging chickens create a risk of disease for wild birds, some of which migrate to the United States, as well as potential economic losses for resource-poor farmers. Free-roaming backyard chickens are commonly kept in shade-grown coffee plantations, habitats that attract large numbers of wild birds. The husbandry and pathogen prevalence of backyard chicken flocks in San Luis, Costa Rica, were investigated. Based on serologic evidence, Newcastle disease virus, infectious laryngotracheitis virus, infectious bronchitis virus, chicken anemia virus, and infectious bursal disease virus, as well as both Mycoplasma gallisepticum and Mycoplasma synoviae, appear to be significant diseases of this population, and thus, we consider these backyard chickens potential reservoirs for these diseases. There was no evidence of avian influenza. Interviews, clinical examinations, and microscopic examination of tissues led us to believe that poxvirus is also a significant cause of morbidity and mortality in these chickens. We found that Escherichia coli isolates were resistant against tilmicosin, tetracycline, ampicillin, amoxicillin with clavulanic acid, ticarcillin, and cephalothin, and contained genes considered responsible for conferring tetracycline resistance. Additionally, although production was not measured, we suspect that husbandry and lack of preventative medicine are directly related to the diseases reported, all of which negatively affect production.

Infectious bursal disease subunit vaccination.

Infectious bursal disease virus (IBDV) is the causative agent of infectious bursal disease, a nosologic entity with global economic importance in poultry. The viral protein 2 (VP2) is recognized as the virus' major antigenic protein. The goal of this study was to generate yeast (Pichia pastoris)-based protein expression from the VP2 gene of the Edgar strain of IBDV and from the hypervariable region of the VP2 gene (hvVP2) to test the protection afforded against virulent IBDV challenge when inoculated in chickens. The genetic material used for protein expression was obtained from paraffin-embedded tissue. Specific-pathogen-free chickens were vaccinated with the expressed products and challenged with the homologous strain (Edgar). After challenge, no morbidity or mortality was observed in the birds vaccinated with the whole VP2, compared with 30% morbidity and mortality in the hvVP2-vaccinated birds and with 90% morbidity and 60% mortality in the unvaccinated, challenged controls. Immunohistochemistry detection of the challenge virus and some extent of bursal damage were observed in all challenged birds, indicating active replication of the challenge virus despite vaccination. As determined by bursal index values, the protection against postchallenge bursal atrophy was significantly higher (P < 0.05) in the VP2 group than in the unvaccinated and hvVP2-vaccinated birds. Overall, the results indicated that paraffin-embedded tissue can be used as a source of genomic material for transgenic protein expression, that Pichia pastoris-expressed VP2 retains its immunogenicity, and that VP2 subunit vaccination conferred partial protection to challenge; it protected against clinical signs and death but not against IBDV infection.