Financial analysis of brucellosis control for small-scale goat farming in the Bajío region, Mexico.

Brucellosis is an endemic disease in small-scale goat husbandry systems in Mexico. It is a zoonosis and the economic consequences can be large, although estimates are not available for the Mexican goat sector. Our objective was to conduct a financial analysis of brucellosis control in a prominent dairy goat production area of the Bajío region, Mexico. We used three models: (1) a brucellosis transmission model at village flock level (n=1000 head), (2) a flock growth model at smallholder flock level (n=23 head) using output of model 1 and (3) cost-benefit analysis of several brucellosis control scenarios based on output of model 2. Scenarios consisted of test-and-slaughter or vaccination or a combination of both compared to the base situation (no control). The average net present values (NPV) of using vaccination over a 5-year period was 3.8 US$ (90% CI: 1.3-6.6) and 20 US$ (90% CI: 11.3-28.6) over a 10-year period per goat. The average benefit-cost ratios over a 5-year period and 10-year period were 4.3 US$ (90% CI: 2.2-6.9) and 12.3 US$ (90% CI: 7.5-17.3) per goat, respectively. For the total dairy goat population (38,462 head) of the study area (the Bajío of Jalisco and Michoacán) the NPV's over a 5-year and 10-year period were 0.15 million US$ and 0.8 million US$. However, brucellosis prevalence was predicted to remain relatively high at about 12%. Control scenarios with test-and-slaughter predicted to reduce brucellosis prevalence to less than 3%, but this produced a negative NPV over a 5-year period ranging from -31.6 to -11.1 US$ and from -31.1 to 7.5 US$ over a 10-year period. A brucellosis control campaign based on vaccination with full coverage is economically profitable for the goat dairy sector of the region although smallholders would need financial support in case test-and-slaughter is applied to reduce the prevalence more quickly.

Economic analysis of vaccination to control bovine brucellosis in the States of Sao Paulo and Mato Grosso, Brazil.

Brucellosis is a zoonotic disease that causes important economic losses in Brazil, and the country has therefore established a national program for its control and eradication. Using data generated in the last national brucellosis survey, we conducted an economic analysis in two Brazilian States with different brucellosis status, Mato Grosso (with high prevalence) and Sao Paulo (with low prevalence). The economic analysis was based on the calculation of the additional benefits and costs of controlling bovine brucellosis through the vaccination of heifers aged between 3 and 8 months with S19 vaccine, considering maximal and minimal impacts of the disease. The analysis showed that vaccinating 90% of the replacement heifers aged 3-8 months of age offers the best economic performance in a vaccination program against bovine brucellosis if compared to vaccination rates of 70% and 80%. Moreover, regions with higher prevalences of bovine brucellosis would experience significant economic advantages when implementing a vaccination strategy to control the disease. This economic analysis will allow decision makers to plan more economically effective vaccination programs.

[Leptospirosis outbreak in calves from Corrientes Province, Argentina]. / Brote de leptospirosis en terneros en recría en la provincia de Corrientes, Argentina.

Leptospirosis is an infectious disease resulting in significant economic losses in livestock production. This disease causes abortion, embryo death, death of calves within the first few days of life and mastitis. We report a leptospirosis outbreak in calf growing and fattening. Histopathological and hemoparasite studies, immunofluorescence, and bacterial cultures were performed. A strain of Leptospira interrogans serovar Pomona was isolated from samples collected from dead calves.

Vaccines based on the cell surface carbohydrates of pathogenic bacteria

Vacinas glicoconjugadas, cujo carboidrato da superfície de um microrganismo está covalentemente ligado a uma proteína carreadora, vêm sendo consideradas como efetivas para gerar respostas imunes que previnem um grande número de doenças. A tecnologia é genérica e aplicável a vários patógenos, se os anticorpos contra os carboidratos de superfície forem capazes de proteger contra a infecção. Três vacinas contra Haemophilus influenzae tipo b, Neissseria meningitidis Grupo C e sete sorotipos de Streptococcus pneumoniae já foram licenciadas e muitas outras estão em desenvolvimento. Este artigo discute o racional para o desenvolvimento e uso de vacinas glicoconjugadas; os mecanismos pelos quais elas induzem respostas imune dependentes de célula T e suas implicações para o seu desenvolvimento; o papel dos métodos físico-químicos na caracterização e no controle de qualidade dessas vacinas; e os produtos novos que estão em desenvolvimento.

Vaccines based on the cell surface carbohydrates of pathogenic bacteria.

Glycoconjugate vaccines, in which a cell surface carbohydrate from a micro-organism is covalently attached to an appropriate carrier protein are proving to be the most effective means to generate protective immune responses to prevent a wide range of diseases. The technology appears to be generic and applicable to a wide range of pathogens, as long as antibodies against surface carbohydrates help protect against infection. Three such vaccines, against Haemophilus influenzae type b, Neisseria meningitidis Group C and seven serotypes of Streptococcus pneumoniae, have already been licensed and many others are in development. This article discusses the rationale for the development and use of glycoconjugate vaccines, the mechanisms by which they elicit T cell-dependent immune responses and the implications of this for vaccine development, the role of physicochemical methods in the characterisation and quality control of these vaccines, and the novel products which are under development.

[Use of diafiltration in the lavage of cultures of Leptospira interrogans canicola canicola for the production of vaccine vax-SPIRAL]. / Empleo de la diafiltración en el lavado de cultivos de Leptospira interrogans canicola canicola para la producción de la vacuna vax-SPIRAL.

It was proposed to substitute the present technology of the lavage operation for a tangential microfiltration system at the lavage stages of the culture of Leptospira interrogans canicola canicola. It was proved that this system may be applied, since no cellular affectation was observed and high pollutant elimination levels were obtained.

[Scale-up of the fermentation of Leptospira interrogans canicola canicola for the production of vax-SPIRAL vaccine]. / Escalado de la fermentación de Leptospira interrogans canicola canicola para la producción de la vacuna vax-SPIRAL.

The operational conditions for the production of vaccine vax-SPIRAL were established at the scale of 100 L. It was concluded that it should be carried out with an air flow of 10 L/min (0.1 vvm) and without mechanical agitation.

Prophylaxis against respiratory syncytial virus (RSV), varicella, and pneumococcal infections: Economic-based decision-making.

OBJECTIVE: To compare costs and health benefits of three prophylactic interventions recommended by the American Academy of Pediatrics (AAP) and to help quantify the impact of illness and enhance the physicians' ability to make informed decisions. STUDY DESIGN: Medline search was conducted of English-language cost-effectiveness studies of varicella and pneumococcal conjugate vaccination recommended for all healthy infants and of respiratory syncytial virus (RSV) prophylaxis with palivizumab (Synagis) for infants at high risk for severe RSV infection. Data were collected on cost-effectiveness, burden of illness, and efficacy and analyzed from the societal and payer perspective. Results were discounted by 5% and costs inflated to year 2002 dollars. RESULTS: From the societal perspective, estimates of cost per life-years saved were money savings for varicella, 175,300 US dollars for pneumococcal conjugate vaccination, and 66,200 US dollars for palivizumab prophylaxis; from the payer perspective, estimates were 28,100, 338,400, and 66,400 US dollars, respectively. CONCLUSIONS: Cost-effectiveness estimates for varicella and pneumococcal conjugate vaccination demonstrate that evaluating economic benefits from the societal rather than the payer perspective makes universal prophylaxis very financially attractive. By comparison, this same differential does not exist for the cost-effectiveness estimates of palivizumab from the societal and payer perspectives because its use is in a well-defined high-risk target population. From a societal perspective, prophylaxis is a rational public policy decision, although in target populations, incidence of serious illness and the primary cost components driving the cost offsets vary across prophylactic measures studied.

Cost-benefit analysis for the use of Haemophilus influenzae type b conjugate vaccine in Santiago, Chile.

Cost-benefit analyses can be integral to the evaluation of interventions in developing countries. The authors compare the potential benefits to the Chilean Ministry of Health, in terms of treatment costs averted, by prevention of Haemophilus influenzae type b (HIB) invasive disease, with the costs of adding HIB conjugate vaccine to the diphtheria-tetanus-pertussis (DTP) immunization routinely administered to infants. In their basecase model, over a 10-year period (1991-2000), vaccination against HIB will prevent 1,229 cases of HIB invasive disease, including 713 cases of meningitis, 107 of whom would suffer severe, long-term sequelae, and between 29 and 116 deaths. Assuming a cost of US$1 for a full three-dose regimen of vaccine, the benefit/cost ratio of 1.66, with a net discounted savings of over $403,225, illustrates that HIB vaccine can be cost-beneficial. Sensitivity analyses which alter each of the variables in the analysis indicate that if the true incidence of HIB disease is twice the published rate, then three doses of vaccine remains cost-beneficial at US#3.

PIP: Health practitioners reviewed the clinical records of all 6-60 month old children who were treated for meningitis caused by Haemophilus influenzae type b (HIB) in 1989-1990 at Roberto del Rio Children's Hospital in Santiago, Chile, to estimate costs for all phases of meningitis treatment (ambulatory visits, hospitalization, and follow-up). They also estimated annual HIB incidence. They determined the cost of adding HIB conjugate vaccine to the DTP vaccine. They assumed a cost of US$1 for a full 3-dose regimen of vaccine. They then conducted a cost benefit analysis of the use of HIB conjugate vaccine to prevent invasive HIB disease in Santiago. The National Health Service had to pay an average of US$1301/case of HIB meningitis and US$887/case of HIB invasive disease other than meningitis, including pre- and post-hospitalization costs and adjustment for frequency of sequelae. Several factors indicated that the estimates were actually underestimates. For example, the researchers did not take into account herd immunity and the fact that sequelae often do not appear until the children are older. The addition of the HIB conjugate vaccine to the immunization program would prevent at least 1229-3111 cases of HIB invasive disease, disabling sequelae, and deaths during a 10-year period. Further, it would save the National Health Service more than US$403,225. The benefit/cost ratio was 1.66. The researchers changed each of the variables in the cost benefit analysis. These sensitivity analyses revealed that if the true incidence of HIB disease were 2 times greater than the based on reported data, the 3 doses of HIB conjugate vaccine would still have a cost benefit of US$3. These results indicated that adding HIB conjugate vaccine would exert a considerable public health and cost benefit. Cost benefit analyses of vaccines would also prove useful to decision-makers in other developing countries.