Diagnostic accuracy of commercially available serological tests for the detection of measles and rubella viruses: a systematic review and meta-analysis

Measles and rubella serological diagnoses are done by IgM detection. The World Health Organization Global Measles and Rubella Laboratory Network previously endorsed Siemens Enzygnost enzyme-linked immunosorbant assay kits, which have been discontinued. A recommended replacement has not been determined. We aimed to search for suitable replacements by conducting a systematic review and meta-analysis of IgM detection methods that are currently available for measles and rubella. A systematic literature search was performed in Medline, Embase, Global Health, Cochrane Central, and Scopus on March 22 and on 27 September 2023. Studies reporting measles and/or rubella IgM detection with terms around diagnostic accuracy were included. Risk of bias was assessed using QUADAS tools. Meta-DiSc and R were used for statistical analysis. Clinical samples totalling 5,579 from 28 index tests were included in the measles meta-analysis. Sensitivity and specificity of the individual measles studies ranged from 0.50 to 1.00 and 0.53 to 1.00, respectively. Pooled sensitivity and specificity of all measles IgM detection methods were 0.94 (CI: 0.90-0.97) and 0.94 (CI: 0.91-0.97), respectively. Clinical samples totalling 4,983 from 15 index tests were included in the rubella meta-analysis. Sensitivity and specificity of the individual rubella studies ranged from 0.78 to 1.00 and 0.52 to 1.00, respectively. Pooled sensitivity and specificity of all rubella IgM detection methods were 0.97 (CI: 0.93-0.98) and 0.96 (CI: 0.93-0.98), respectively. Although more studies would be ideal, our results may provide valuable information when selecting IgM detection methods for measles and/or rubella.

Genome sequence of a measles virus strain with a novel loss of stop codon mutation in the phosphoprotein gene

Measles virus genotype B3 coding-complete genome sequence from a 2019 case showed a novel mutation in the phosphoprotein (P) gene that abrogates the established stop codon. A downstream stop codon has been identified, resulting in a putative P that would be 19 amino acids longer than wild type.

Dimeric immunoglobulin A as a novel diagnostic marker of measles infection

IMPORTANCE

The world is facing a measles resurgence, and improved diagnostic tests for measles infection are an urgent World Health Organization research priority. Detection of measles-specific immunoglobulin M (IgM) as a standard diagnostic test has low positive predictive value in elimination settings, and there is a need for new biomarkers of measles infection to enable enhanced surveillance and response to outbreaks. We demonstrate the detection of measles-specific dimeric immunoglobulin A (dIgA) in patients with confirmed measles infections using a new indirect enzyme-linked immunosorbent assay protocol that selects for the dIgA fraction from total IgA in the blood. The magnitude of measles-specific dIgA responses showed a low correlation with IgM responses, and our results highlight the potential of dIgA for further development as an alternative and/or complementary biomarker to IgM for serological diagnosis of measles infection.

Mumps resurgence in a highly vaccinated population: Insights gained from surveillance in Canada, 2002-2020

Although mumps vaccination has been routine in Canada for decades, mumps cases and outbreaks continue to occur periodically. Mumps surveillance, including monitoring of the mumps virus genotype associated with disease activity, is important to document baseline activity and to advance further research into vaccine effectiveness. Here we describe a detailed analysis of mumps cases that have been detected in Canada from 2002 to 2020, with a focus on the mumps molecular epidemiology. In total, 7395 cases of mumps were reported to the surveillance system, with outbreaks occurring in the years 2007, 2010 and 2016 to 2018. Adolescents and young adults aged 15 to 29 years had the highest risk of being a case (rate ratios ranging from 1.50 to 2.29), compared to adults aged 30 to 39. Genotypes of mumps viruses were determined in 3225 specimens. Genotype G was predominantly detected (96% of genotyped specimens) and was first reported in 2005. Other genotypes were more likely to be detected in cases that also reported travel (or were linked to imported cases) than the cases with genotype G detected (p < 0.0001). The genotype G viruses had little sequence diversity in the 316 nucleotide window used for genotyping (the small hydrophobic protein gene) and mainly belonged to a single phylogenetic lineage that included the MuVi/Sheffield.GBR/1.05 reference sequence. The analysis of over ten years of data has demonstrated that mumps genotype G, specifically belonging to a single lineage, the Sheffield lineage, is the endemically circulating virus in Canada. This lineage is seen also in other countries using the genotype A vaccine. Mumps remains endemic despite high MMR vaccination coverage which has been sufficient to eliminate circulation of measles and rubella in Canada, raising the hypothesis of the evolution towards a vaccine escape mumps virus.

Development of a rapid, internally controlled, two target, real-time RT-PCR for detection of rubella virus

Rubella surveillance in elimination setting relies on rapid molecular detection of the virus. In this study a multiplex real-time RT-PCR assay for the detection of rubella virus was validated. The assay includes three independent probes with unique reporter dyes for the simultaneous detection of the rubella viral coding regions for envelope glycoprotein E1 and non-structural p150 protein, and an endogenous control (human RNaseP). Using dilution series of synthetic RNAs, the limits of detection were determined to be at least 50 copies of rubella RNA. The assay is reproducible with low intra-assay and inter-assay coefficients of variation for both the E1 and the p150 targets. After testing 62 confirmed rubella positive and 165 rubella negative archival clinical samples, the sensitivity and specificity of the multiplex assay were 98.4 and 100%, respectively. No cross reactivity was identified with clinical specimens positive for eleven other viruses. This multiplex assay successfully detected nine viral genotypes including the predominant genotypes 1E, 1 G, 1 J, and 2B as well as the 1a vaccine genotype.

Re-verifying the elimination of measles, rubella and congenital rubella syndrome in Canada, 2016-2020

Elimination, in the context of measles, rubella and congenital rubella syndrome (CRS), refers to the absence of endemic measles/rubella virus transmission in a region or other defined geographic area for at least 12 months, in the presence of a high-quality surveillance system that meets targets of key performance indicators. In 1994, Canada and other countries of the World Health Organization (WHO) region of the Americas committed to the objectives of measles elimination by 2000 and rubella and CRS by 2010. Canada met these targets: eliminating measles transmission in 1998; rubella transmission in 2005; and endemically-acquired CRS in 2000. The WHO region of Americas was declared free of endemic rubella/CRS in 2015 and endemic measles in 2016. At the request of the Pan American Health Organization (PAHO), Canada’s elimination status of measles, rubella and CRS was verified in 2012 and again in 2017. Prior to submission to PAHO, the verification reports were reviewed, approved and endorsed by Canada’s National Certification Committee (NCC). The NCC is a group of experts who are not directly involved with the management of vaccine preventable diseases or immunization program implementation at the national level, but who have the expertise to assist in ensuring that Canada is meeting PAHO’S goals of elimination and eradication. Members are responsible for reviewing Canada’s current mechanisms of surveillance and progress towards elimination of targeted vaccine preventable diseases in Canada. Members have expertise in the fields of public health, infectious diseases and/or laboratory sciences.

Development of a rapid, internally controlled, two target, real-time RT-PCR for detection of measles virus

Vaccination has greatly reduced global measles incidence, however measles remains endemic in many regions worldwide. Measles surveillance relies on high performance molecular detection of the virus. We have developed and validated a multiplex rRT-PCR assay for the detection of measles virus. The assay includes three independent probes with unique reporter dyes for the simultaneous detection of the measles hemagglutinin gene, nucleoprotein gene and endogenous RNaseP control. Using dilution series of synthetic RNAs the limits of detection were determined to be approximately 20 copies of measles RNA. The assay is extremely reproducible with very low intra-assay and inter-assay coefficients of varation for both the N and the H targets. After testing 68 confirmed measles positive and 86 measles negative archival clinical samples our data shows the multiplex assay has a sensitivity and specificity of 100 %, and a 100 % concordance with the expected results. No cross reactivity was identified with clinical specimens positive for six other viruses. According to the WHO, currently only the B3, D4, D8, H1 measles genotypes of the 24 recognized genotypes continue to circulate and this new multiplex assay successfully detected all four of those genotypes as well as six other genotypes.

An enrichment method for capturing mumps virus whole genome sequences directly from clinical specimens

Recently there has been a significant increase in the number of mumps outbreaks occurring in highly vaccinated populations. These outbreaks are often due to a mumps genotype G virus, where sequencing of the SH gene does not reveal enough genetic diversity to sufficient to resolve outbreaks. This has elevated the need to be able to sequence complete mumps viruses from clinical samples without laborious methods. Here we describe a probe enrichment method that allows for whole genome sequencing of the mumps virus directly from clinical specimens. Using 136 clinical samples, we show this method allows for a significant increase in the percentage of viral sequencing reads, resulting in the capture of mumps genomes. This method will be an asset in investigating future mumps outbreaks.

Measles surveillance in Canada, 2019

BACKGROUND

The Public Health Agency of Canada (PHAC) has conducted enhanced measles surveillance since 1998, the year endemic measles transmission was eliminated in Canada. The objective of this annual national measles surveillance report is to provide an epidemiologic summary of measles activity reported in Canada for 2019 in order to provide evidence to support the continued verification of Canada's measles elimination status.

METHODS

Measles surveillance data are housed in the Canadian Measles and Rubella Surveillance System (CMRSS) database. Descriptive analyses of demographics and risk factors were performed. Outbreak characteristics were summarized and genotypic analyses conducted. Surveillance, laboratory and vaccine coverage data for 2019 were used to assess Canada's status against the Pan American Health Organization (PAHO) essential criteria for the verification of measles elimination.

RESULTS

In 2019, 113 measles cases were reported in Canada (crude incidence rate of 3.0 cases per 1,000,000 population). Of these cases, 42 (37%) were imported into Canada, and of the imported cases, 12 (29%) resulted in further transmission. Infants younger than one year had the highest age-specific incidence rate at 13.1 cases per 1,000,000 population. Only 29% of cases had one or more documented doses of measles-containing vaccine. One-fifth (19%) of cases were hospitalized; no deaths were reported. Genotype information was available for 100% of outbreaks reported in 2019 and 90% of non-outbreak-related measles cases; of cases with genotype information available, 27% were B3 and 73% were D8.

CONCLUSION

Despite meeting/partially meeting only three out of four of PAHO's essential criteria for measles elimination status, there is no evidence that endemic measles transmission has been reestablished in Canada.

Cost-effectiveness of measles control during elimination in Ontario, Canada, 2015

BackgroundGiven that measles is eliminated in Canada and measles immunisation coverage in Ontario is high, it has been questioned whether Ontario's measles outbreak response is worthwhile.AimOur objective was to determine cost-effectiveness of measles containment protocols in Ontario from the healthcare payer perspective.MethodsWe developed a decision-analysis model comparing Ontario's measles containment strategy (based on actual 2015 outbreak data) with a hypothetical 'modified response'. The modified scenario assumed 10% response costs with reduced case and contact tracing and no outbreak-associated vaccinations; it was based on local and provincial administrative and laboratory data and parameters from peer-reviewed literature. Short- and long-term health outcomes, quality-adjusted life years (QALYs) and costs discounted at 1.5%, were estimated. We conducted one- and two-way sensitivity analyses.ResultsThe 2015 outbreak in Ontario comprised 16 measles cases and an estimated 3,369 contacts. Predictive modelling suggested that the outbreak response prevented 16 outbreak-associated cases at a cost of CAD 1,213,491 (EUR 861,579). The incremental cost-effectiveness ratio was CAD 739,063 (EUR 524,735) per QALY gained for the outbreak response vs modified response. To meet the commonly accepted cost-effectiveness threshold of CAD 50,000 (EUR 35,500) per QALY gained, the outbreak response would have to prevent 94 measles cases. In sensitivity analyses, the findings were robust.ConclusionsOntario's measles outbreak response exceeds generally accepted cost-effectiveness thresholds and may not be the most efficient use of public health resources from a healthcare payer perspective. These findings should be balanced against benefits of increased vaccine coverage and maintaining elimination status.

Measles Lymphadenopathy in a Child With PFAPA Syndrome

Periodic fever, aphthous stomatitis, pharyngitis, and cervical adenitis (PFAPA) syndrome is a common cause of periodic fever in children. The pathogenesis of PFAPA is unknown but likely involves immune system dysregulation and may be initiated by an environmental trigger. Tonsillectomy resolves or improves symptoms in some patients, but the reason for this is unknown; moreover, specific abnormalities in tonsillectomy specimens from PFAPA patients have not been described. Here, we report measles virus in tonsil from a child with PFAPA. Measles-type viral cytopathic effect was discovered on histological examination of tonsillar tissue after therapeutic tonsillectomy for PFAPA. Molecular testing showed the left tonsil was positive for measles RNA by reverse transcription polymerase chain reaction (RT-PCR) while the right tonsil was inconclusive (weakly positive). Real-time RT-PCR specific for measles vaccine strain RNA (genotype A) was weakly reactive in the left tonsil tissue when tested in 3 independent replicates, but this result could not be confirmed with conventional genotyping by sequencing. The relationship and clinical significance between measles virus and PFAPA in this case is unclear but may be related to PFAPA-associated immune dysregulation. Additional investigation of measles virus in PFAPA patients would be helpful in further exploring this potential association.

Measles Outbreak with Unique Virus Genotyping, Ontario, Canada, 2015

The province of Ontario continues to experience measles virus transmissions despite the elimination of measles in Canada. We describe an unusual outbreak of measles in Ontario, Canada, in early 2015 that involved cases with a unique strain of virus and no known association among primary case-patients. A total of 18 cases of measles were reported from 4 public health units during the outbreak period (January 25–March 23, 2015); none of these cases occurred in persons who had recently traveled. Despite enhancements to case-patient interview methods and epidemiologic analyses, a source patient was not identified. However, the molecular epidemiologic analysis, which included extended sequencing, strongly suggested that all cases derived from a single importation of measles virus genotype D4. The use of timely genotype sequencing, rigorous epidemiologic investigation, and a better understanding of the gaps in surveillance are needed to maintain Ontario’s measles elimination status.

Evaluation of 5 Commercially Available Zika Virus Immunoassays

Because of the global spread of Zika virus, accurate and high-throughput diagnostic immunoassays are needed. We compared the sensitivity and specificity of 5 commercially available Zika virus serologic assays to the recommended protocol of Zika virus IgM-capture ELISA and plaque-reduction neutralization tests. Most commercial immunoassays showed low sensitivity, which can be increased.

Comparison of monoplex and duplex RT-PCR assays for the detection of measles virus

Rapid and accurate detection of measles virus is important for case diagnosis and public health management. This study compared the performance of two monoplex RT-PCR reactions targeting the H and N genes to a duplex RT-PCR targeting both genes simultaneously. The duplex simplified processing without compromising assay performance characteristic.

Measles surveillance in Canada: 2015

BACKGROUND

Measles has been eliminated in Canada since 1998. Every year, the Public Health Agency of Canada presents epidemiologic evidence to the Pan American Health Organization (PAHO) to verify that measles elimination continues in Canada.

OBJECTIVE

To describe measles activity in Canada for 2015 as updated evidence for continued measles elimination status.

METHODS

Measles surveillance data were captured by the Canadian Measles and Rubella Surveillance System (CMRSS) and the Measles and Rubella Surveillance (MARS) pilot project and assessed for distribution by demographics and risk factors. Outbreak characteristics were summarized and genotypic and phylogenetic analyses were conducted and described. Surveillance data for 2015 were evaluated against PAHO's essential criteria for measles elimination status.

RESULTS

In 2015, the incidence of measles in Canada was 5.5 cases per 1,000,000 population, with 196 cases across four provinces. The majority of cases (87.2%, n=171) were not immunized and both age-specific incidence rates and case counts were highest among those aged 10 to 14 years (29.5 cases per 1,000,000 population, n=55). This was due in large part to a sizeable outbreak in a non-immunizing religious community. Overall, 10.7% (n=21) of cases were hospitalized. Genotype information was available for 100% of measles events (4/4 outbreaks and 6/6 sporadic cases). Canada met or partially met most of PAHO's criteria for verification of measles elimination.

CONCLUSION

Although importations and areas of low immunization coverage continue to challenge Canada's elimination status, surveillance data for 2015 provides strong evidence that measles elimination has been maintained.

Measles surveillance in Canada: Trends for 2014

BACKGROUND

Measles elimination status was achieved in Canada in 1998. The Public Health Agency of Canada compiles evidence for the Pan American Health Organization to confirm that criteria for the verification of measles elimination continue to be met.

OBJECTIVE

To describe measles activity in Canada for 2014 in order to support Canada's ongoing measles elimination status.

METHODS

Using data captured by the Canadian Measles and Rubella Surveillance System and the Measles and Rubella Surveillance pilot project during 2014, the distribution of measles cases by demographics, immunization status and hospitalization were assessed, outbreak characteristics were summarized and genotypic and phylogenetic analyses were conducted and described.

RESULTS

During 2014, 418 measles cases were reported by five provinces and territories for an overall incidence rate of 11.8 cases per 1,000,000 population. Case counts and incidence rates were highest among those five to 14 years of age and the majority of cases were not immunized. Overall, five percent of cases were hospitalized, most frequently the youngest and oldest age groups. Eighteen outbreaks were reported, the largest of which occurred in a non-immunizing religious community in British Columbia. Genotype information was available for 98% of measles events (18/18 outbreaks and 31/32 sporadic cases). Canada continued to meet or partially meet all four of PAHO's criteria for verification of measles elimination.

CONCLUSION

Despite significant measles activity in 2014, Canada continues to provide strong evidence that measles elimination status is being maintained.

Measles in Canada Between 2002 and 2013

Background.  In 1994, Canada committed to eliminate measles by the year 2000. This report presents the epidemiology of measles in Canada between 2002 and 2013 and its implications in sustaining measles elimination. Methods.  Cases included individuals reported to the Canadian Measles and Rubella Surveillance System with confirmed measles. Results.  In Canada, 1171 cases of measles were reported between 2002 and 2013 (incidence 0.29 cases per 100 000 population). The annual number of cases ranged from 6 to 752. The majority of cases were unvaccinated (63%) or had an unknown vaccination status (19%). The median age of cases was 14.4 years (range, <1 to 63 years) globally and 14 years when excluding the 2011 outbreak in Quebec where 68% of the 678 cases were 10 to 19 years old. With the exclusion of this outbreak, the incidence was highest in infants (1.0 per 100 000), lower but fairly similar between 1 and 19 years of age (0.2 to 0.4 per 100 000), and there was a substantial decline between 20 and 39 years of age (0.1 per 100 000). There was a significant trend towards a greater annual number of importations over the period. Although importations resulted in no transmission sustained for ≥12 months, 5 chains of transmission had >30 cases. The effective reproductive number between 2002 and 2013 was estimated at 0.86 (95% confidence interval, .81-.92). Conclusions.  Canada has maintained elimination between 2002 and 2013, but additional efforts are needed to reduce the proportion of unimmunized individuals and respond to importation events.

Measles molecular epidemiology: What does it tell us and why is it important?

Measles molecular epidemiology was a key component of the verification of elimination of indigenous measles in Canada and is an invaluable tool during public health investigations, both to establish whether connections exist between concurrent measles cases and to indicate possible sources of importations. There are 24 distinct genotypes however the genotype is usually not sufficient to describe the complex molecular epidemiology of measles cases. The exact genetic sequence of the last 450 nucleotides of the nucleoprotein (N) gene (N-450) is used. The measles genome mutates very slowly and so cases within the same chain of transmission usually have identical N-450 sequences. In Canada, the National Microbiology Laboratory (NML) sequences the N-450 and deposits it into the WHO measles sequence database, MeaNS. This database can be used to identify other geographic regions where the measles sequence was detected, supporting or excluding connections. For commonly detected N-450 sequences, MeaNS designates a "sequence variant." Sequence variants are used as the defining characteristic of measles cases with identical sequences and this designation is fundamental to the description of measles molecular epidemiology both locally and globally. As progress is made towards global measles eradication, its genetic diversity decreases and distinct importations of measles from a single reservoir can be difficult to distinguish using current methods. Extending sequencing methods beyond the N-450 is required. While sequencing the entire hemagglutinin (H) gene, which is currently done routinely at the NML, can be helpful, whole genome sequencing will be required for effective molecular surveillance to monitor the sustained elimination of measles in Canada.insert text here.

Measles surveillance in Canada: Trends for 2013

OBJECTIVE

The objective of this report is to describe measles activity in Canada during 2013, in order to support the documentation and maintenance of measles elimination status.

METHODS

A descriptive analysis of measles counts and incidence by age group, immunization history, hospitalization and province/territory, as well as a summary of 2013 outbreaks, was conducted using enhanced measles data captured through the Canadian Measles and Rubella Surveillance System. Genotype information and phylogenetic analysis for 2013 were summarized.

RESULTS

In 2013, 83 confirmed measles cases were reported in seven provinces/territories for an incidence rate of 2.4 per 1,000,000 population. Incidence was highest in the youngest age groups (< 1 year, 1 to 4 years). Burden of disease was highest in the youngest age groups and children 10 to 14 years. Three-quarters of cases had been inadequately immunized, and 10% were hospitalized. There were nine measles outbreaks reported in 2013, one of which consisted of 42 cases in a non-immunizing community in Alberta.

DISCUSSION

2013 saw the fifth highest number of reported measles cases since 1998. While we continue to face challenges related to importation and heterogeneous immunization coverage, in 2013 Canada met or partially met all four criteria outlined by the Pan American Health Organization for measles elimination.

Case of vaccine-associated measles five weeks post-immunisation, British Columbia, Canada, October 2013

We describe a case of vaccine-associated measles in a two-year-old patient from British Columbia, Canada, in October 2013, who received her first dose of measles-containing vaccine 37 days prior to onset of prodromal symptoms. Identification of this delayed vaccine-associated case occurred in the context of an outbreak investigation of a measles cluster.

Detection of measles, mumps, and rubella viruses

Measles, mumps, and rubella are infections caused by RNA viruses of the same name and are vaccine preventable. The vaccines are frequently administered in a trivalent form. Laboratory diagnostic methods can include indirect detection via antibody (IgM and IgG) detection methods and direct detection by viral culture or viral genome detection. There are challenges for the laboratory in areas with low prevalence due to high vaccine uptake. In those areas, routine serological methods such as IgM detection may have a reduced positive predictive value and thus require confirmation by other methods. Direct detection of viral genomic material using reverse transcription polymerase chain reaction (RT-PCR) methodologies can play an important role for laboratory confirmation of acute infections. Furthermore, genotyping of these three viruses provides useful molecular epidemiological data for differentiating vaccine from wild-type strains, linking cases and outbreaks, and tracking geographic spread and elimination. The purpose of this chapter is to provide guidance for the laboratory diagnosis of measles, mumps, and rubella virus infections. Where assays are commercially available or previously published, the appropriate references are provided as well as brief comments on the interpretation of results. Detailed protocols are provided for the molecular assays which have been developed and more commonly applied in recent years.

Complete DNA sequence analyses of the first two varicella-zoster virus glycoprotein E (D150N) mutant viruses found in North America: evolution of genotypes with an accelerated cell spread phenotype

Varicella-zoster virus (VZV) is considered to be one of the most genetically stable of all the herpesviruses. Yet two VZV strains with a D150N missense mutation within the gE glycoprotein were isolated in North America in 1998 and 2002. The mutant strains have an accelerated cell spread phenotype, which distinguishes them from all wild-type and laboratory viruses. Since the VZV genome contains 70 additional open reading frames (ORFs), the possibility existed that the phenotypic change was actually due to an as-yet-undiscovered mutation or deletion elsewhere in the genome. To exclude this hypothesis, the entire genomes of the two mutant viruses were sequenced and found to contain 124,883 (VZV-MSP) and 125,459 (VZV-BC) nucleotides. Coding single-nucleotide polymorphisms (SNPs) were identified in 14 ORFs. One missense mutation was discovered in gH, but none was found in gB, gI, gL, or gK. There were no coding SNPs in the major regulatory protein ORF 62. One polymorphism was discovered which could never have been anticipated based on current knowledge of herpesvirus genomics, namely, the origins of replication differed from those in the prototype strain but not in a manner expected to affect cell spread. When the two complete mutant VZV sequences were surveyed in their entirety, the most reasonable conclusion was that the increased cell spread phenotype was dependent substantially or solely on the single D150N polymorphism in glycoprotein gE. The genomic results also expanded the evolutionary database by identifying which VZV ORFs were more likely to mutate over time.

Reinnervation of denervated iris by transplanted sympathetic ganglia: effect of neuronal age

Neuronal outgrowth in vivo is aggressive postnatally, but is diminished with increasing age. This may be attributable to intrinsic features of the neuron or its interaction with other components of the developing organism. The purpose of this study was to determine if there is an age-dependent reduction in the intrinsic ability of sympathetic neurons to initiate fiber outgrowth. Superior cervical ganglia from donor rats aged 3-4, 11-12, 27-28 and 45-46 days were removed and transplanted to the anterior chamber of the sympathectomized eye of host rats 85-89 days of age. Ganglia with host irides were removed at 3, 6 and 10 days post-transplant and whole mounts were analysed using catecholamine histofluorescence for maximum sympathetic fiber density, length and initial rate of outgrowth. Fluorescent fibers were present in host irides of donors of all ages and at all post-transplant times. However, maximum fiber density was less for the 3-4-day-old donor ganglia (e.g. 43-71% of 11-46-day-old donor ganglia at 600 microns, 10 days post-transplant). Maximum fiber length was also less in the youngest group (e.g. 35-49% of 11-46-day-old donor ganglia, 10 days post-transplant). Further, the initial rate of outgrowth was decreased for the 3-4-day-old donor ganglia (128 +/- 46 microns/day for the 3-4-day-old ganglia vs 253 +/- 48 microns/day for the 11-12-day-old ganglia, 307 +/- 35 microns/day for the 27-28-day-old ganglia and 260 +/- 22 microns/day for the 45-46-day-old ganglia).(ABSTRACT TRUNCATED AT 250 WORDS)

Autonomic and sensory reinnervation of smooth muscle transplanted to the anterior chamber of the eye: effect of target postnatal age

The ability of the nervous system to provide target innervation is greatest in early development, but decreases as a function of age. The objective of the present study was to determine if age-related changes occurring within the target tissue contribute to this decline. Periorbital tarsal smooth muscle from donor rats 6, 14, 30, and 48 days postnatal were transplanted to the anterior chamber of the eye of 84- to 90-day-old host rats. The tissue was removed at 3, 6, or 10 days post-transplant and immunostained for presumptive sympathetic nerves (dopamine beta-hydroxylase-immunoreactive, DBH-ir), sensory (calcitonin gene-related peptide-immunoreactive, CGRP-ir) or parasympathetic (vasoactive intestinal polypeptide-immunoreactive, VIP-ir). DBH-ir sympathetic fibers sprouted into target from donors of all ages. However, the rate of ingrowth was most rapid in tissue from 6-day-old donors. In contrast, CGRP-ir sensory fibers showed no age-related differences, but grew more rapidly than sympathetic fibers. However, the innervation density at 10 days was comparable for both types of nerves. No significant VIP-ir parasympathetic ingrowth could be demonstrated at any age. We conclude that smooth muscle target in developing animals can have selective effects on different populations of ingrowing fibers; the rate of sympathetic ingrowth declines with maturity, whereas ingrowth of sensory fibers is not altered.

Modification of the American Burn Association injury severity grading system

This study evaluated the regional burn health care system of the Commonwealth of Virginia using the criteria for optimal care of the burn patient designated by the American Burn Association. The data base for this evaluation was hospital records of seven hospitals in Virginia. The major shortcoming of the designated criteria was the grading system for the severity of burn injury. Using the criteria designated by the American Burn Association, a large number of minor burn injuries were judged erroneously to be major burn injuries. A modification of the American Burn Association's injury severity grading system is proposed which more precisely identifies the minor burn injury.