Validation of the ultrasonographic assessment of the femoral trochlea epiphyseal cartilage in foals at osteochondrosis predilected sites with magnetic resonance imaging and histology.

BACKGROUND: Noninvasive imaging tools are needed to screen foal femoropatellar joints to detect subclinical osteochondrosis lesions due to focal failure of endochondral ossification to enhance early management to optimise intrinsic healing events. Recently investigations employing 3T susceptibility-weighted magnetic resonance imaging (3T SWI MRI) and CT have demonstrated their capacity for early osteochondrosis diagnosis, but these technologies are not practical for field screening. We postulate that ultrasonography is a valuable field tool for the detection of subclinical osteochondrosis lesions. OBJECTIVES: The goals were to 1) describe the ultrasonographic features of the femoral trochlea of healthy and osteochondrosis-predisposed neonatal foals, 2) validate the capacity of ultrasound to assess cartilage canal vascular archictecture and the ossification front and 3) evaluate field feasibility in a pilot study. STUDY DESIGN: Experimental study. METHODS: Ultrasonographic evaluation of osteochondrosis predisposed (n = 10) and control (n = 6) femoral trochleas was performed ex vivo and compared with site-matched histological sections and 3T SWI MRI. The articular and epiphyseal cartilage thickness, ossification front indentation and cartilage canal vascular archictecture were assessed at each ROI. Femoral trochleae of foals (n = 3) aged ≈ 1, 3 and 6 months were also evaluated with ultrasonography in field. RESULTS: Ultrasonographic measurements strongly correlated with the histological measurements. There was no difference in the cartilage thickness or ossification front indentation between control and osteochondrosis-predisposed specimens. The cartilage canal vascular archictecture on ultrasonograms corresponded with the vessel pattern observed on site matched histology and 3T SWI MRI. MAIN LIMITATIONS: The number of specimens for study was limited and no early osteochondrosis lesions were present within the predilected group, but a field study is now underway. CONCLUSION: Ultrasonographic examination of the femoral trochlea permitted accurate evaluation of cartilage thickness, cartilage canal vascular archictecture and ossification front indentation in young foals and is a promising, practical tool for screening subclinical osteochondrosis and monitoring and managing lesions at important clinical sites.

An inventory of nursing education research.

PURPOSE: To describe nursing education research literature in terms of quality, content areas under investigation, geographic location of the research, research designs utilized, sample sizes, instruments used to collect data, and funding sources. DESIGN AND METHODS: Quantitative and qualitative research literature published between January 1991 and December 2000 were identified and classified using an author-generated Relevance Tool. FINDINGS: 1286 articles were accepted and entered into the inventory, and an additional 22 were retained as references as they were either literature reviews or meta-analyses. Not surprisingly, 90% of nursing education research was generated in North America and Europe, the industrialised parts of the world. Of the total number of articles accepted into the inventory, 61% were quantitative research based. The bulk of the research was conducted within the confines of a course or within a program, with more than half based in educational settings. Sample sizes of the research conducted were diverse, with a bare majority using a sample between 50 and 99 participants. More than half of the studies used questionnaires to obtain data. Surprising, 80% of the research represented in these articles was not funded. The number of publications of nursing education research generated yearly stabilised at approximately 120 per year. CONCLUSION: Research programs on teaching and learning environments and practice in nursing education need to be developed. Lobbying is needed to increase funding for this type of research at national and international levels.

Measles vaccination in Africa: by how much could routine coverage be improved?

Assuming that the level of Bacille Calmette Guerin (BCG) coverage gives a measure of access to immunisation services, it is possible to derive what fraction of infants are not immunised against measles due to under-utilisation of existing services (rather than unavailability of services). According to the most recent official statistics, the overall coverage for measles vaccine is 53% in Africa (10% lower than for BCG). This difference amounts to 3 million African children who will not be vaccinated against measles this year even though they probably have access to immunisation services.

When is a disease eradicable? 100 years of lessons learned.

Since the 1915 launch of the first international eradication initiative targeting a human pathogen, much has been learned about the determinants of eradicability of an organism. The authors outline the first 4 eradication efforts, summarizing the lessons learned in terms of the 3 types of criteria for disease eradication programs: (1) biological and technical feasibility, (2) costs and benefits, and (3) societal and political considerations.

Disease eradication as a public health strategy: a case study of poliomyelitis eradication.

Disease eradication as a public health strategy was discussed at international meetings in 1997 and 1998. In this article, the ongoing poliomyelitis eradication initiative is examined using the criteria for evaluating candidate diseases for eradication proposed at these meetings, which covered costs and benefits, biological determinants of eradicability (technical feasibility) and societal and political considerations (operational feasibility). The benefits of poliomyelitis eradication are shown to include a substantial investment in health services delivery, the elimination of a major cause of disability, and far-reaching intangible effects, such as establishment of a "culture of prevention". The costs are found to be financial and finite, despite some disturbances to the delivery of other health services. The "technical" feasibility of poliomyelitis eradication is seen in the absence of a non-human reservoir and the presence of both an effective intervention and delivery strategy (oral poliovirus vaccine and national immunization days) and a sensitive and specific diagnostic tool (viral culture of specimens from acute flaccid paralysis cases). The certification of poliomyelitis eradication in the Americas in 1994 and interruption of endemic transmission in the Western Pacific since March 1997 confirm the operational feasibility of this goal. When the humanitarian, economic and consequent benefits of this initiative are measured against the costs, a strong argument is made for eradication as a valuable disease control strategy.

Disease eradication and health systems development.

This article provides a framework for the design of future eradication programmes so that the greatest benefit accrues to health systems development from the implementation of such programmes. The framework focuses on weak and fragile health systems and assumes that eradication leads to the cessation of the intervention required to eradicate the disease. Five major components of health systems are identified and key elements which are of particular relevance to eradication initiatives are defined. The dearth of documentation which can provide "lessons learned" in this area is illustrated with a brief review of the literature. Opportunities and threats, which can be addressed during the design of eradication programmes, are described and a number of recommendations are outlined. It is emphasized that this framework pertains to eradication programmes but may be useful in attempts to coordinate vertical and horizontal disease control activities for maximum mutual benefits.

The impact of immunization control activities on measles outbreaks in middle and low income countries.

BACKGROUND: The World Health Organization recommended strategy for responding to measles outbreaks in developing countries does not promote the use of immunization campaigns due to their high cost, disruptive nature and limited impact. Given the substantial morbidity and mortality associated with such outbreaks, a literature review was conducted as a basis for re-evaluating this policy. METHODS: Reports of supplementary immunization activities that were performed to control measles outbreaks in middle or low income countries were identified. The impact of the immunization activities on the course of each outbreak was evaluated by examining the data provided. RESULTS: Of 66 reports detailing a measles outbreak in a middle or low income country, 17 described supplementary immunization activities which included seven 'non-selective' immunization campaigns, three 'selective' campaigns and one use of an early 2-dose schedule. Eight of the reports commented on the impact of the response, five of which reported a reduction in outbreak morbidity. Only one of the reports, from an isolated island outbreak, provided sufficient data to support a possible reduction in outbreak-associated morbidity. CONCLUSIONS: There are limited data on the impact of measles outbreak immunization activities from developing countries. The available data do not support a change in the WHO recommended strategy for conducting a limited, if any, immunization response to such outbreaks. Immunization strategies which aim to prevent outbreaks may be more effective than campaigns to interrupt transmission of an outbreak which has already begun.

PIP: Because of their high cost, disruptive nature, and limited impact, immunization campaigns are not recommended by the World Health Organization (WHO) in response to measles outbreaks in developing countries. The authors reviewed the available literature to assess whether that WHO policy should stand or be changed. 66 reports were identified detailing a measles outbreak in middle- or low-income countries. 17 of those reports described supplementary immunization activities to control measles outbreaks which included seven nonselective immunization campaigns, three selective campaigns, and one use of an early two-dose schedule. Eight reports commented upon the impact of the intervention, five of which reported a reduction in outbreak morbidity. Only one report, from an isolated island outbreak, provided sufficient data to support a possible reduction in outbreak-associated morbidity. The available data therefore do not support a change in the WHO-recommended strategy. Immunization strategies to prevent outbreaks may be more effective than campaigns to interrupt transmission of an outbreak which has already begun.

The desired field-performance characteristics of new improved vaccines for the developing world.

Although the vaccination initiatives undertaken during the past decade are the cornerstones for protecting the world's children and helping to ensure their survival and development, the vaccines currently being employed may become obstacles for further disease reduction or eradication. Their characteristics complicate or increase the burden on health care infrastructures to maintain or expand vaccine delivery systems. This paper examines an experience with the vaccine technologies that currently are being used by immunization programs in developing countries, illustrating the field problems and obstacles associated with their use. It discusses the advantages and benefits that would accrue if new or improved, heat-stable, multi-antigen vaccines that require only one or two, preferably oral, doses were to become available.

PIP: Smallpox was eradicated in 1977 with immunity conferred by a simple, heat-stable vaccine administered in single doses. Most currently available vaccines used against vaccine-preventable diseases, however, require refrigeration and administration in multiple doses. The recurrent costs of managing and administering such vaccines are high. A new set of vaccines is therefore called for. Ideal vaccines will be administered in one or two doses, be taken earlier in life, have no side effects, be heat-stable and not require refrigeration in the field. The availability of such vaccines would ensure the control and/or eradication of diseases, reduce costs on health systems and parents, and encourage parents to vaccinate their children. This paper reviews vaccine technologies currently used in immunization programs in developing countries discusses associated field problems and obstacles. Advantages and benefits of new or improved multi-antigen vaccines are considered.