Evaluation of the Relationship Between the Breeders Age, Breed and the Incubator Types on Quality and Animal Welfare in the Hatchery

About 33.3% of chicken life is conditioned by the result of embryonic development. Therefore, understanding and improving the early phase of the broilers life is critical to guarantee their well-being. Thus, the objective of this research was to evaluate the relationship between the breeders age, breed and the incubator types on quality and animal welfare in the hatchery. The experimental design was completely randomized in a 2 x 2 x 3 factorial arrangement (incubator, breed and age), with 12 treatments and 6 replicates each. The eggs derived of Cobb 500 and Rosss breeders at the beginning of the laying period, middle age and at the end of the laying period. It is concluded that the size of the eggs is related to the breeders age and breed, which influences directly the number of bled eggs. In addition, well-being in the hatchery can be affected by decreased hatching and contamination that is higher in older breeders. Cobb eggs also need more attention because they are larger, therefore, they have a higher risk of breakage and they are more sensitive to the low concentration of CO2 at the hatcher.

Evaluation of the Relationship Between the Breeders Age, Breed and the Incubator Types on Quality and Animal Welfare in the Hatchery

About 33.3% of chicken life is conditioned by the result of embryonic development. Therefore, understanding and improving the early phase of the broilers life is critical to guarantee their well-being. Thus, the objective of this research was to evaluate the relationship between the breeders age, breed and the incubator types on quality and animal welfare in the hatchery. The experimental design was completely randomized in a 2 x 2 x 3 factorial arrangement (incubator, breed and age), with 12 treatments and 6 replicates each. The eggs derived of Cobb 500 and Rosss breeders at the beginning of the laying period, middle age and at the end of the laying period. It is concluded that the size of the eggs is related to the breeders age and breed, which influences directly the number of bled eggs. In addition, well-being in the hatchery can be affected by decreased hatching and contamination that is higher in older breeders. Cobb eggs also need more attention because they are larger, therefore, they have a higher risk of breakage and they are more sensitive to the low concentration of CO2 at the hatcher.(AU)

Role of co-solute in biomolecular stability: glucose, urea and the water structure.

We have studied the action of urea and glucose on the stability of DNAand micelles. We measured the melting temperature of aqueous solutionsof DNA with urea or glucose as a co-solute; we have also measured thechanges in the critical micelle concentrations (cmc) of Sodium DodecylSulfate and Triton X-100 by addition of urea and glucose. Ourexperimental results show that glucose increases the melting temperature ofDNA and decreases the cmc, while urea acts in the contrary direction. The effects of urea and glucose on the stability of DNA and micelles canbe explained by the weakening and enhancement of hydrophobicinteractions, respectively. These effects on hydrophobic interactions arediscussed in this paper.

Clinical case definitions for Argentine hemorrhagic fever.

Argentine hemorrhagic fever (AHF) is a potentially lethal infection in Argentina. The case-fatality ratio is >15%, but treatment reduces the mortality rate to <1%. Diagnosis is based on clinical and laboratory criteria, but no case definition has been validated. A chart review was conducted for patients hospitalized with suspected AHF. Individuals with a fourfold rise in antibody titer were classified as cases. The combination of a platelet count of <100,000/mm3 and a white blood cell (WBC) count of <2,500/mm3 had a sensitivity and specificity of 87% and 88%, respectively, thus suggesting that the use of these criteria in a case definition would be helpful for epidemiological studies of AHF. The combination of a platelet count of <100,000/mm3 and a WBC count of <4,000/mm3 had a sensitivity of 100% and a specificity of 71%; the use of these criteria in a case definition should be helpful for screening patients for therapy with immune plasma in the region where AHF is endemic.

Protective efficacy of a live attenuated vaccine against Argentine hemorrhagic fever. AHF Study Group.

Argentine hemorrhagic fever (AHF), caused by the arenavirus Junin, is a major public health problem among agricultural workers in Argentina. A prospective, randomized, double-blind, placebo-controlled, efficacy trial of Candid 1, a live attenuated Junin virus vaccine, was conducted over two consecutive epidemic seasons among 6500 male agricultural workers in the AHF-endemic region. Twenty-three men developed laboratory-confirmed AHF during the study; 22 received placebo and 1 received vaccine (vaccine efficacy 95%; 95% confidence interval [CI], 82%-99%). Three additional subjects in each group developed laboratory-confirmed Junin virus infection associated with mild illnesses that did not fulfill the clinical case definition for AHF, yielding a protective efficacy for prevention of any illness associated with Junin virus infection of 84% (95% CI, 60%-94%). No serious adverse events were attributed to vaccination. Candid 1, the first vaccine for the prevention of illness caused by an arenavirus, is safe and highly efficacious.

Characterization of Oliveros virus, a new member of the Tacaribe complex (Arenaviridae: Arenavirus).

Oliveros virus is an agent isolated in cell culture from Bolomys obscurus (Rodentia, Muridae, Sigmodontinae) captured on the central Argentine pampa. Oliveros virus was shown to be related to members of the Tacaribe complex of the family Arenaviridae by immunofluorescent antibody (IFA) tests, electrophoretic pattern of viral proteins, and morphology as observed by electron microscopy. It was distinct from 12 other arenaviruses by a combination of plaque-reduction neutralization tests, comparison of endpoint titers among cross-IFA tests, and comparison of viral RNA sequence data. This agent is the third new arenavirus from South America described within the last three years.

On the levels of enzymatic substrate specificity: implications for the early evolution of metabolic pathways.

The most frequently invoked explanation for the origin of metabolic pathways is the retrograde evolution hypothesis. In contrast, according to the so-called "patchwork" theory, metabolism evolved by the recruitment of relatively inefficient small enzymes of broad specificity that could react with a wide range of chemically related substrates. In this paper it is argued that both sequence comparisons and experimental results on enzyme substrate specificity support the patchwork assembly theory. The available evidence supports previous suggestions that gene duplication events followed by a gradual neoDarwinian accumulation of mutations and other minute genetic changes lead to the narrowing and modification of enzyme function in at least some primordial metabolic pathways.

Safety and immunogenicity of a live-attenuated Junin (Argentine hemorrhagic fever) vaccine in rhesus macaques.

The safety and immunogenicity of Candid #1, a live-attenuated Junin virus vaccine, were evaluated in rhesus macaques. Candid #1 was inoculated subcutaneously in graded doses ranging from 16 to 127,200 plaque-forming units (PFU) into four groups of five animals each; four controls received saline. There was no significant effect of the immunization on any physical, hematologic, or biochemical parameter measured. Junin virus was recovered by cocultivation from peripheral blood mononuclear cells (PBMC) of 14 (70%) of 20 animals from 1 to 21 days after immunization; 27 (12%) of 223 PBMC samples that represented animals in all four dose groups were positive. In contrast, virus was recovered from the plasma of only two of 20 macaques (two of 225 samples [0.9%]), and only once (by amplification) from throat swabs. No evidence of reversion was detected in any blood isolate. All animals developed a detectable neutralizing antibody response following vaccination. These results indicate that Candid #1 is safe and immunogenic in nonhuman primates.

Candid No. 1 Argentine hemorrhagic fever vaccine protects against lethal Junin virus challenge in rhesus macaques.

The protective efficacy of Candid No. 1, a live-attenuated vaccine against Argentine hemorrhagic fever (AHF), was evaluated in non-human primates. Twenty rhesus macaques immunized 3 months previously with graded doses of Candid No. 1 (16-127, 000 PFU), as well as 4 placebo-inoculated controls, were challenged with 4.41 log10 PFU of virulent P3790 strain Junin virus. All controls developed severe clinical disease; 3 of 4 died. In contrast, all vaccinated animals were fully protected; none developed any signs of AHF during a 105-day follow-up period. Viremia and virus shedding were readily detected in all placebo-vaccinated controls, while virus could be recovered only once (by amplification) from throat swabs of 2 Candid No. 1 vaccinees on day 21. Vigorous secondary-type neutralizing and immunofluorescent antibody responses were seen in most vaccinees that had received 3 log10 PFU Candid No. 1 or fewer; all others, including those receiving 127,200 PFU, maintained relatively stable titers during follow-up. Candid No. 1 was highly immunogenic and fully protective against lethal Junin virus challenge in rhesus macaques, even at extremely low (16 PFU) vaccine doses.

Junin virus activity in rodents from endemic and nonendemic loci in central Argentina.

Small mammals were trapped during a 21-month period at 27 farm sites in 15 localities within and beyond the known endemic area for Argentine hemorrhagic fever (AHF). Prevalence of Junin virus (JV) was assessed by antigen-capture enzyme immunoassay (ELISA) on samples of body fluids and/or organs from 3, 282 captured rodents. Infection in rodent populations was variable (0-3.7%) among localities but, in all cases, was lower than previously reported rates. Overall prevalence was 1.4% in the AHF epidemic area, 0.6% in the historic (currently low incidence of AHF) area, and 0.4% in two localities beyond the previously defined endemic area. These low values underestimate the actual prevalence of JV, as ELISA validation by virus isolation indicated a sensitivity of 30% and a specificity of 99%. Of 37 positive rodents, 28 (76%) were of two species: Calomys musculinus (23 animals) and C. laucha (5 animals). Antigen also was found in three Akodon azarae, four Bolomys obscurus, one Mus musculus, and one Oxymycterus rufus, and JV was isolated from two Oligoryzomys flavescens. Three of these rodent species (B. obscurus, O. flavescens, and O. rufus) have heretofore not been implicated in JV maintenance in the field. Evidence suggests that the AHF endemic area may continue to expand northward.

[New findings on Junin virus infection in rodents inside and outside the endemic area of hemorrhagic fever in Argentina]. / Nuevas observaciones de la infección de roedores por el virus Junin dentro y fuera de la zona endemica de la Fiebre Hemorragica Argentina.

In conjunction with field trials for a vaccine against Argentine Hemorrhagic Fever (AHF), small mammals were trapped during a 28-month period (1 November 1987 to 13 March 1990) in 3 epidemiologically defined areas of the central Argentine pampas: northern and central Buenos Aires provinces were included in the AHF "historic" area, where the disease was common 15-20 years ago, but case rates are currently low; southern Santa Fe province is the current high-incidence area for AHF; the nonendemic area was represented by two localities 60-90 km beyond the northernmost extension of human disease. Animals were live-trapped for 3 days per month in permanent "mark-recapture" grids in each of the 3 areas. Samples of blood, sera, and oral swabs were taken from these animals before they were marked and released at the site of capture. In addition, "removal" traplines provided animals from 16 localities in these 3 areas which were sacrificed to obtain samples of organs in addition to the aforementioned samples. Samples were tested for the presence of Junin virus (JV) antigen by enzyme immunoassay (ELISA). In this assay, a pool of 13 mouse anti-JV glycoprotein and nucleocapsid monoclonal antibodies adsorbed to the surface of microtiter plates was used to capture JV antigen in sample suspensions. A polyclonal rabbit anti-JV antiserum was added as a detector antibody, and an anti-rabbit antibody conjugated to horseradish peroxidase applied with substrate to complete the sandwich.(ABSTRACT TRUNCATED AT 250 WORDS)

Toward a vaccine against Argentine hemorrhagic fever.

A vaccine against Argentine hemorrhagic fever, the "mal de los rastrojos" of the pampas, has been a dream of physicians and scientists involved with the disease since its recognition in the 1950s. Several killed and live immunogens have been produced and tested in pursuit of this goal, none of which has proved suitable for widespread human use. Recently, a new live-attenuated Junin virus vaccine, Candid #1, was developed through a cooperative international effort. Testing conducted to date indicates that this vaccine holds considerable promise.

Nuevas observaciones de la infección de roedores por el virus Junin dentro y fuera de la zona endemica de la Fiebre Hemorragica Argentina. / [New findings on Junin virus infection in rodents inside and outside the endemic area of hemorrhagic fever in Argentina]

In conjunction with field trials for a vaccine against Argentine Hemorrhagic Fever (AHF), small mammals were trapped during a 28-month period (1 November 1987 to 13 March 1990) in 3 epidemiologically defined areas of the central Argentine pampas: northern and central Buenos Aires provinces were included in the AHF [quot ]historic[quot ] area, where the disease was common 15-20 years ago, but case rates are currently low; southern Santa Fe province is the current high-incidence area for AHF; the nonendemic area was represented by two localities 60-90 km beyond the northernmost extension of human disease. Animals were live-trapped for 3 days per month in permanent [quot ]mark-recapture[quot ] grids in each of the 3 areas. Samples of blood, sera, and oral swabs were taken from these animals before they were marked and released at the site of capture. In addition, [quot ]removal[quot ] traplines provided animals from 16 localities in these 3 areas which were sacrificed to obtain samples of organs in addition to the aforementioned samples. Samples were tested for the presence of Junin virus (JV) antigen by enzyme immunoassay (ELISA). In this assay, a pool of 13 mouse anti-JV glycoprotein and nucleocapsid monoclonal antibodies adsorbed to the surface of microtiter plates was used to capture JV antigen in sample suspensions. A polyclonal rabbit anti-JV antiserum was added as a detector antibody, and an anti-rabbit antibody conjugated to horseradish peroxidase applied with substrate to complete the sandwich.(ABSTRACT TRUNCATED AT 250 WORDS)

Nuevas observaciones de la infección de roedores por el virus Junin dentro y fuera de la zona endemica de la Fiebre Hemorragica Argentina. / [New findings on Junin virus infection in rodents inside and outside the endemic area of hemorrhagic fever in Argentina]

In conjunction with field trials for a vaccine against Argentine Hemorrhagic Fever (AHF), small mammals were trapped during a 28-month period (1 November 1987 to 13 March 1990) in 3 epidemiologically defined areas of the central Argentine pampas: northern and central Buenos Aires provinces were included in the AHF [quot ]historic[quot ] area, where the disease was common 15-20 years ago, but case rates are currently low; southern Santa Fe province is the current high-incidence area for AHF; the nonendemic area was represented by two localities 60-90 km beyond the northernmost extension of human disease. Animals were live-trapped for 3 days per month in permanent [quot ]mark-recapture[quot ] grids in each of the 3 areas. Samples of blood, sera, and oral swabs were taken from these animals before they were marked and released at the site of capture. In addition, [quot ]removal[quot ] traplines provided animals from 16 localities in these 3 areas which were sacrificed to obtain samples of organs in addition to the aforementioned samples. Samples were tested for the presence of Junin virus (JV) antigen by enzyme immunoassay (ELISA). In this assay, a pool of 13 mouse anti-JV glycoprotein and nucleocapsid monoclonal antibodies adsorbed to the surface of microtiter plates was used to capture JV antigen in sample suspensions. A polyclonal rabbit anti-JV antiserum was added as a detector antibody, and an anti-rabbit antibody conjugated to horseradish peroxidase applied with substrate to complete the sandwich.(ABSTRACT TRUNCATED AT 250 WORDS)

Nuevas observaciones de la infección de roedores por el virus Junin dentro y fuera de la zona endemica de la Fiebre Hemorragica Argentina / [New findings on Junin virus infection in rodents inside and outside the endemic area of hemorrhagic fever in Argentina]

In conjunction with field trials for a vaccine against Argentine Hemorrhagic Fever (AHF), small mammals were trapped during a 28-month period (1 November 1987 to 13 March 1990) in 3 epidemiologically defined areas of the central Argentine pampas: northern and central Buenos Aires provinces were included in the AHF [quot ]historic[quot ] area, where the disease was common 15-20 years ago, but case rates are currently low; southern Santa Fe province is the current high-incidence area for AHF; the nonendemic area was represented by two localities 60-90 km beyond the northernmost extension of human disease. Animals were live-trapped for 3 days per month in permanent [quot ]mark-recapture[quot ] grids in each of the 3 areas. Samples of blood, sera, and oral swabs were taken from these animals before they were marked and released at the site of capture. In addition, [quot ]removal[quot ] traplines provided animals from 16 localities in these 3 areas which were sacrificed to obtain samples of organs in addition to the aforementioned samples. Samples were tested for the presence of Junin virus (JV) antigen by enzyme immunoassay (ELISA). In this assay, a pool of 13 mouse anti-JV glycoprotein and nucleocapsid monoclonal antibodies adsorbed to the surface of microtiter plates was used to capture JV antigen in sample suspensions. A polyclonal rabbit anti-JV antiserum was added as a detector antibody, and an anti-rabbit antibody conjugated to horseradish peroxidase applied with substrate to complete the sandwich.(ABSTRACT TRUNCATED AT 250 WORDS)

Kairi virus identified from a febrile horse in Argentina.

A virus isolated from the blood of a febrile horse in Argentina was identified as a strain of Kairi virus. This is the fifth Bunyamwera serogroup virus isolated from livestock and wild animals in the Americas. Bunyamwera serogroup viruses have been isolated from febrile humans in the Americas and Africa.

Psittacosis in humans in Argentina (1977-1981)

Ha sido estudiada en Argentina la incidencia de Chlamydia psittaci durante el período 1977-1981 empleando la técnica de fijación de complemento en 949 muestras de sueros obtenidas de pacientes con datos epidemiológicos y/o clínicos compatibles con ornitosis. Del total, 387 (41%) presentaron anticuerpos contra antígeno de Chlamydia psittaci. La incidencia fue mayor en adultos que en niños y en hombres que en mujeres. Hubo mayor incidencia en primavera que en las restantes estaciones. En el 25% de los casos positivos no se pudo establecer el antecedentes de contacto con aves. Hubo 2 casos de contagio inter-humano. Con posterioridad al brote epidémico de 1977 se observa entre 1978 y 1981 un incremento anual del número de casos diagnosticados. Resta dilucidar si esto es debido a un aumento real de la enfermedad o a un mejor conocimiento de la misma (AU)