Prevalence and spatial distribution of bovine brucellosis in San Luis and La Pampa, Argentina.

BACKGROUND: Bovine brucellosis (BB) is a zoonotic disease caused by Brucella abortus. BB is endemic in Argentina, where vaccination with Brucella abortus strain 19 is compulsory for 3-to-8 month-old heifers. The objectives of this study were to quantify the prevalence of BB and to identify factors associated with its occurrence, along with the spatial distribution of the disease, in the provinces of La Pampa and San Luis. A two-stage random sampling design was used to sample 8,965 cows (3,513 in La Pampa and 5,452 in San Luis) from 451 farms (187 in La Pampa and 264 in San Luis). RESULTS: Cow and herd prevalence were 1.8 % (95 % CI: 1.3-2.2; n = 157) and 19.7 % (95 % CI: 17.0-22.4; n = 89), respectively. Both cow-level and herd-level prevalence in La Pampa (2.4 and 26.0 %, respectively) were significantly higher than in San Luis (1.4 and 15.5 %, respectively). There were not differences between the proportions of reactive cattle compared to that obtained in a survey conducted in 2005. However, herd prevalence in La Pampa was significantly (P < 0.05) higher compared to that study. Disease was found to be spatially clustered in west La Pampa. The lower the bovine density and the calf/cow ratio, the higher odds of belonging to the cluster. CONCLUSIONS: The increase of farm prevalence in the last five years suggests that the disease is spreading and that control measures should be applied in the region. The cluster of infected farms was located in the west region of La Pampa. There, farms have lower animal densities and smaller cow/calf indices compared to the rest of the province. Although western La Pampa has more infected herds, within-farm prevalence was not higher, which suggests that the control program has been relatively successful in controlling the disease at the farm level, and/or that low animal density inherently results in low disease prevalence. Our results provide baseline information on the epidemiology of BB and its potential pattern of transmission in Argentina, which will ultimately help to improve BB control programs in the country.

Effectiveness of systematic foot and mouth disease mass vaccination campaigns in Argentina.

The objective of this paper is to evaluate the effectiveness of systematic mass vaccination campaigns against foot and mouth disease in Argentina. The analysis was based on an estimation of the proportion of protected animals and protected farms in vaccinated populations, as reflected by levels of antibodies measured in liquid-phase enzyme-linked immunosorbent assay. The analysis was carried out in 49 animal health districts in Buenos Aires province, using data collected from four cross-sectional studies, in 2004, 2007, 2008 and 2011. Cattle were assigned to one of two categories on the basis of correlation between serological titres and expected percentage protection: non-adequately protected (expected protection < 75%) and adequately protected (expected protection ≥ 75%). The proportions of adequately protected cattle and significantly non-adequately protected farms were estimated and compared among sampled locations. Protection was variable among the districts; cattle aged one to two years showed higher levels of protection than cattle six to 12 months old, and the proportion of protected cattle was higher in the more recent studies. The results of the analysis will allow the national animal health service to investigate in depth those districts where protection was lower than the regional background protection. The authors propose that this methodology could be used to evaluate the effectiveness of vaccination campaigns in other countries or zones where systematic foot and mouth disease mass vaccination campaigns are undertaken.

A description of cattle movements in two departments of Buenos Aires province, Argentina.

We present a descriptive analysis of cattle movement information retrieved from the Argentinean animal movement database for two departments in the province of Buenos Aires during 2004. For each quarter of the year (January to March, April to June, July to September, and October to December) we report the number of on- and off-farm movement events for the purpose of finishing. Our analyses show that the distribution of the number of finishing-related movement events per farm was skewed, with the majority of farms reporting at least 1 and less than 5% of farms of reporting greater than 15 finishing related movement events throughout the year. The frequency of finishing-related movement events varied over time, with a 1.2-1.8-fold increase in reported movement events from April to September, compared with the rest of the year. These analyses indicate that cattle movement patterns in these departments are dependent on the relative mix of constituent cattle enterprise types. Departments with a mixture of breeding and finishing enterprises behave as potential recipients and distributors of infectious disease, whereas departments comprised of primarily finishing enterprises are predominantly recipients of infectious disease, rather than distributors. Data integrity audits of the Argentinean animal movement database, on a regular or intermittent basis, should allow the presence of bias in these data to be quantified in greater detail.

The oral contraceptive pill effectively permits cycle batching for an intermittent in vitro fertilization programme in Trinidad and Tobago.

Assisted reproductive technology (ART) in small island states like Trinidad and Tobago is usually provided in batches so as to minimize the cost of providing the service. As a result, patients 'cycles have to be synchronized in order to coincide with the arrival of a visiting embryologist. This is a retrospective study which evaluates the experience of pre-treatment with an oral contraceptive pill (OCP) as a means of batching cycles for an intermittent ART programme. Seventy-four in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI) cycles in which OCP usage was employed (Group A), were compared with 121 cycles which did not require pharmaceutical manipulation (Group B). In both groups more than 50% of women were older than 36-years. Two cycles were cancelled in Group A and seven in Group B, because of poor ovarian response. Although the pregnancy rate per treatment cycle was higher in Group A than in Group B (26.3% vs 17.3%), this difference was not significant. More spontaneous miscarriages occurred in the non-OCP women and ovarian cyst formation was more common in these women. The authors experience indicates that the OCP is a simple, cheap and efficient means of batching patients for an intermittent ART programme and can be utilized in other small ART centres.

The oral contraceptive pill effectively permits cycle batching for an intermittent in vitro fertilization programme in Trinidad and Tobago / Las Píldoras Anticonceptivas Orales Permiten la Agrupación Eficaz de los Ciclos para un Programa Intermitente de FIV en Trinidad y Tobago

Assisted reproductive technology (ART) in small island states like Trinidad and Tobago is usually provided in batches so as to minimize the cost of providing the service. As a result, patients 'cycles have to be synchronized in order to coincide with the arrival of a visiting embryologist. This is a retrospective study which evaluates the experience of pre-treatment with an oral contraceptive pill (OCP) as a means of batching cycles for an intermittent ART programme. Seventy-four in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI) cycles in which OCP usage was employed (Group A), were compared with 121 cycles which did not require pharmaceutical manipulation (Group B). In both groups more than 50 of women were older than 36-years. Two cycles were cancelled in Group A and seven in Group B, because of poor ovarian response. Although the pregnancy rate per treatment cycle was higher in Group A than in Group B (26.3 vs 17.3), this difference was not significant. More spontaneous miscarriages occurred in the non-OCP women and ovarian cyst formation was more common in these women. The authors experience indicates that the OCP is a simple, cheap and efficient means of batching patients for an intermittent ART programme and can be utilized in other small ART centres

La tecnología de reproducción asistida (TRA) en los pequeños estados insulares como Trinidad y Tobago, usualmente se ofrece por tandas a fin de minimizar los costos del servicio brindado. En consecuencia, los ciclos de las pacientes tienen que ser sincronizados de modo que coincidan con la visita del embriólogo. Éste es un estudio retrospectivo que evalúa la experiencia del pretratamiento con píldoras anticonceptivas orales (PAO) como medio de agrupar los ciclos con el propósito de organizar un programa intermitente de TRA. Setenta y cuatro ciclos de fertilización in vitro (FIV) e inyección intracitoplasmática de esperma (ICSI) en los que se recurrió al uso de PAO (Grupo A), fueron comparados con 121 ciclos que no requirieron manipulación farmacéutica (Grupo B). En ambos grupos, > 50% de las mujeres tenían más de 36 años de edad. Dos ciclos fueron cancelados en el grupo A y siete en el grupo B, debido a una respuesta ovárica pobre. Aunque la tasa de embarazo por ciclo de tratamiento fue más alta en el grupo A que en el grupo B (26.3% vs. 17.3%), esta diferencia no fue significativa. El número de abortos espontáneos fue mayor y la formación de quistes ováricos más común, en las mujeres que tomaron PAO. La experiencia de los autores indica que la PAO es un medio simple, económico y eficaz de agrupar a los pacientes en un programa intermitente de TRA, y puede utilizarse en otros centros pequeños de TRA.

Incidence and isolation of bluetongue virus infection in cattle of the Santo Tomé Department, Corrientes Province, Argentina.

Sentinel herds were monitored for the detection of bluetongue (BT)-specific antibodies and virus over two periods, namely: June 1999 to August 2000 and September 2000 to April 2001. Herds were located in Santo Tomé (Herds 1 and 2) where BTV activity was known to occur. From June 1999 to August 2000, the cumulative incidence (CI) of bluetongue virus (BTV) infection was 0% and 35% in Herds 1 and 2, respectively. In the second period, the CI of BTV infection was 10% and 97% in Herds 1 and 2, respectively. The virus was isolated from red blood cells of animals that seroconverted and was identified as serotype 4. Averages of the monthly maximal temperatures were always above 19 degrees C. However, averages of the monthly median temperatures were below 19 degrees C and averages of the monthly minimal temperatures were below 15 degrees C from May 2000 to August 2000. There was no viral activity detected at that time. Culicoides insignis was identified as the predominant potential vector species (99%) trapped near sentinel herds. Although clinical disease has never been reported in Argentina, viral activity was detected and the virus has been isolated in sentinel herds.

[Bluetongue: isolation and characterization of the virus and identification of vectors in northeastern Argentina]. / Lengua Azul: Aislamiento y caracterización del virus e identificación de vectores en el noreste argentino.

To establish if BTV was circulating in Argentina, 94 bovines from the Santo Tomé and Ituzaingó Departments of Corrientes Province were sampled every 30-60 days during 14 months. Red blood cells from those animals that showed seroconvertion with a c-ELISA were processed for virus isolation by inoculation in embryonated chicken eggs and cell cultures. Cells with CPE were positive by direct and indirect immunofluorescence with BTV specific reagents. These samples examined by electron microscopy showed virus particles with BTV morphological characteristics. Blood samples and tissue culture supernantants were positive by RT-PCR technique with primers corresponding to the segment 3 of the BTV genome. Haematophagous insects were captured in one farm using light traps and Culicoides insignis Lutz was the predominant species detected. This is the first isolation of BTV in Argentina from northeastern bovines without any disease symptom.

Lengua Azul: Aislamiento y caracterización del virus e identificación de vectores en el noreste argentino / Bluetongue: isolation and characterization of the virus and identification of vectors in northeastern Argentina

To establish if BTV was circulating in Argentina, 94 bovines from the Santo TomU and Ituzaingó Departments of Corrientes Province were sampled every 30-60 days during 14 months. Red blood cells from those animals that showed seroconvertion with a c-ELISA were processed for virus isolation by inoculation in embryonated chicken eggs and cell cultures. Cells with CPE were positive by direct and indirect immunofluorescence with BTV specific reagents. These samples examined by electron microscopy showed virus particles with BTV morphological characteristics. Blood samples and tissue culture supernantants were positive by RT-PCR technique with primers corresponding to the segment 3 of the BTV genome. Haematophagous insects were captured in one farm using light traps and Culicoides insignis Lutz was the predominant species detected. This is the first isolation of BTV in Argentina from northeastern bovines without any disease symptom.(AU)

Lengua Azul: Aislamiento y caracterización del virus e identificación de vectores en el noreste argentino / Bluetongue: isolation and characterization of the virus and identification of vectors in northeastern Argentina

To establish if BTV was circulating in Argentina, 94 bovines from the Santo TomÚ and Ituzaingó Departments of Corrientes Province were sampled every 30-60 days during 14 months. Red blood cells from those animals that showed seroconvertion with a c-ELISA were processed for virus isolation by inoculation in embryonated chicken eggs and cell cultures. Cells with CPE were positive by direct and indirect immunofluorescence with BTV specific reagents. These samples examined by electron microscopy showed virus particles with BTV morphological characteristics. Blood samples and tissue culture supernantants were positive by RT-PCR technique with primers corresponding to the segment 3 of the BTV genome. Haematophagous insects were captured in one farm using light traps and Culicoides insignis Lutz was the predominant species detected. This is the first isolation of BTV in Argentina from northeastern bovines without any disease symptom.

Lengua Azul: Aislamiento y caracterización del virus e identificación de vectores en el noreste argentino. / [Bluetongue: isolation and characterization of the virus and identification of vectors in northeastern Argentina]

To establish if BTV was circulating in Argentina, 94 bovines from the Santo Tomé and Ituzaingó Departments of Corrientes Province were sampled every 30-60 days during 14 months. Red blood cells from those animals that showed seroconvertion with a c-ELISA were processed for virus isolation by inoculation in embryonated chicken eggs and cell cultures. Cells with CPE were positive by direct and indirect immunofluorescence with BTV specific reagents. These samples examined by electron microscopy showed virus particles with BTV morphological characteristics. Blood samples and tissue culture supernantants were positive by RT-PCR technique with primers corresponding to the segment 3 of the BTV genome. Haematophagous insects were captured in one farm using light traps and Culicoides insignis Lutz was the predominant species detected. This is the first isolation of BTV in Argentina from northeastern bovines without any disease symptom.

Initial experience with in-vitro fertilization technology in the English-speaking Caribbean

This audit documents the first experience with in-vitro Fertilization technology in the English-speaking Caribbean. From 1996 to 2000, 121 cycles have been performed in 99 couples utilizing these techniques. After ovarian stimulation, 1,103 oocytes were retrieved (average 9.1) and of these, 65 fertilized normally, with embryo transfer possible in 111 cycles. Twenty-one pregnancies were recorded (21.2 per patient and 18.9 per embryo transfer) and the live birth rate per patient was 12.1. The trend was for the success rate to be better in patients under age 36 years.

Seroprevalence of bovine leukemia virus in dairy cattle in Argentina: comparison of sensitivity and specificity of different detection methods.

Bovine leukemia virus (BLV) is a retrovirus that induces a chronic infection in cattle, which develop in three possible pathological forms: asymptomatic course, persistent lymphocytosis (PL) and lymphosarcoma. Once infected, cattle remain virus carriers for life and start to show a serological reaction within a few weeks after infection. Eradication and control of the disease is based on early diagnostic and segregation of the carriers. The agar gel immunodiffusion (AGID) test has been the serological test of choice for routine diagnosis of serum samples. Nevertheless, in more recent years, the enzyme-linked immunosorbent assay (ELISA) has replaced the AGID for large scale testing. Although Argentina has over 60 million cattle population, no nationwide studies have been conducted yet to determine the prevalence of the infection. To estimate the rate of BLV infection in dairy cattle in Argentina, a survey for specific antibodies in >10,000 serum samples from animals over 18 months old, belonging to 363 different herds from the largest dairy production areas of the country, was carried out in our laboratory, along 1999. For this purpose, we developed an ELISA to detect serum antibodies against the BLV virus. The cut-off of the ELISA was established over 339 serum samples, using polymerase chain reaction and southern blot (PCR-SB) as confirmatory test. The sensitivity and specificity of the ELISA was of 97.2 and 97.5%, respectively, while the local official AGID test showed a sensitivity of 79.7% and specificity of 99.0%. To know the seroprevalence of BLV on dairy herds, and also the incidence of the infection within the herd, the serological survey was based on individual serum samples. The results show that the prevalence of infected individuals is of 32.85%, while the percentage of infected herds, harboring one or more infected animals, is of 84%. These results indicate a medium level of seropositive animals when taken individually, but a high prevalence of infected farms, which has been notoriously increased in the last 15 years as shown when compared with previous data from particular geographic areas, indicating that BLV constitutes a serious sanitary problem for dairy producers in Argentina. They also indicate the poor sensitivity of the official AGID test used in the country.

Initial experience with in-vitro fertilization technology in the English-speaking Caribbean.

This audit documents the first experience with in-vitro Fertilization technology in the English-speaking Caribbean. From 1996 to 2000, 121 cycles have been performed in 99 couples utilizing these techniques. After ovarian stimulation, 1,103 oocytes were retrieved (average 9.1) and of these, 65% fertilized normally, with embryo transfer possible in 111 cycles. Twenty-one pregnancies were recorded (21.2% per patient and 18.9% per embryo transfer) and the live birth rate per patient was 12.1%. The trend was for the success rate to be better in patients under age 36 years.

Successful pregnancy by intracytoplasmic sperm injection after radiotherapy induced azoospermia

A 27 year old male, who underwent excision and radiotherapy for a pineal gland germinoma four years previously, subsequently developed panhypopituitarism and, thus, complete azoospermia. Gonadotrophin replacement therapy resulted in the production of a small number of motile spermatozoa which were used for Intracytoplasmic Sperm Injection (ICSI) into oocytes obtained from his wife. After successful fertilization and embryo transfer, a singleton intrauterine pregnancy was achieved which resulted in the normal delivery of a morphologically normal male live infant at term.(AU)

Successful pregnancy by intracytoplasmic sperm injection after radiotherapy-induced azoospermia.

A 27-year-old male, who underwent excision and radiotherapy for a pineal gland germinoma four years previously, subsequently developed panhypopituitarism and, thus, complete azoospermia. Gonadotrophin replacement therapy resulted in the production of a small number of motile spermatozoa which were used for Intracytoplasmic Sperm Injection (ICSI) into oocytes obtained from his wife. After successful fertilization and embryo transfer, a singleton intrauterine pregnancy was achieved which resulted in the normal delivery of a morphologically normal male live infant at term.

Foot-and-mouth disease virus-infected but not vaccinated cattle develop antibodies against recombinant 3AB1 nonstructural protein.

Foot-and-mouth disease (FMD) vaccines induce antibodies against structural and some nonstructural proteins present in vaccine preparations. To differentiate between FMDV-infected and vaccinated animals, we developed immunochemical assays capable of detecting antibodies against a FMDV nonstructural protein. Recombinant nonstructural 3AB1 protein was expressed in E.coli and in insect cells and used to detect anti-3AB1 antibodies. ELISA and Western blot analysis showed that sera from cattle infected with FMDV reacted with recombinant 3AB1 protein whereas sera from cattle which had been vaccinated against FMDV, mock-infected, or infected with different bovine viruses did not recognize the 3AB1 protein. In contrast, anti-virus infection associated antigen (VIAA) antibodies were present in both FMDV-infected and vaccinated animals. Detection of anti-3AB1 antibodies in sera of experimentally infected cattle obtained between 7 and 560 days postinfection indicated that immunological tests based on the detection of recombinant 3AB1 protein could be used for the diagnosis of FMDV infection.

[Seroepidemiologic indicators for the evaluation of campaigns for the control of foot-and-mouth disease]. / Indicadores seroepidemiológicos para la evaluación de las campañas de control de fiebre aftosa.

A sero-epidemiological survey was conducted in two districts in Argentina between 1993 and 1995, to provide additional information on the epidemiology of foot and mouth disease (FMD) in Argentina and to assess the level of immunity in cattle populations, and the circulation of FMD virus. As part of the final stage of this survey, a comparison was made of the results obtained by the enzyme-linked immunosorbent assay (ELISA) and agar gel immunodiffusion techniques. Levels of population immunity against the four types of virus included in the vaccine increased progressively during the period of the survey until, in 1995, at the end of the vaccination period, the percentage of animals possessing adequate levels of protection was approximately 77% in yearlings, and more than 94% in cattle over one year old. During the three-year study, there was a clear tendency for viral activity to diminish, until in 1995 when between 3% and 0.6% were positive to the agar gel immunodiffusion test for the antigen associated with viral infection. By contrast, the ELISA detected antibody in about five times as many animals. The authors show how the increase in the level of population immunity was accompanied by a fall in viral activity.

Detection of virus infection-associated antigen and 3D antibodies in cattle vaccinated against foot and mouth disease.

The analysis of sera obtained from animals vaccinated or revaccinated with inactivated vaccines against foot and mouth disease (FMD) virus showed that these vaccines induced antibodies against the virus infection-associated (VIA) antigen, detectable by agar gel immunodiffusion (AGID). The present study evaluates the antibody response to protein 3D and the VIA antigen (VIAA) of FMD virus induced by different vaccines in a group of 51 calves. This response was detected using AGID and a liquid-phase blocking sandwich enzyme-linked immunosorbent assay (ELISA) for anti-3D antibodies (ELISA-3D). No anti-VIAA or anti-3D antibodies were detected after the initial vaccination. Following revaccination, animals giving positive results were detected by both methods. This immune response disappeared 60-120 days post-revaccination (dprv) according to the AGID method, and 90-180 dprv when ELISA-3D was used. Samples of oesophageal-pharyngeal fluid obtained from animals that remained positive for anti-VIAA antibodies at 90-120 dprv gave negative results for viral isolation, indicating that the transitional antibody response induced by the vaccine was due to the presence of non-structural antigens in the vaccine and not to viral infection. These results indicate that the ELISA-3D method could be used as a complementary method for sero-epidemiological studies as an indirect indicator of viral activity, as long as the age and vaccination status of the animals being sampled are taken into consideration.

Initial experience with in-vitro fertilization technology in the English-speaking Caribbean

This audit documents the first experience with in-vitro fertilization techonlogy in the English-speaking Caribbean. From 1996 to 2000, 121 cycles have been performed in 99 couples utilizing these techniques. After ovarian stimulation, 1103 oocytes were retrieved (average 9.1) and of these, 65 percent fertilized normally, with embryo transfer possible in 111 cycles. Twenty-one pregnancies were recorded (21.2 percent per patient and 18.9 percent per embryo transfer) and the live birth rate per patient was 12.1 percent. The trend was for the success rate to be better in patients under age 36 years. (AU)