Optimal risk-based allocation of disease surveillance effort for clustered disease outbreaks

Designing a disease surveillance program to detect a disease is challenging when animals are organized into herds, in part because disease cases are likely to be clustered. Clustered diseases are often surveilled using two-stage sampling, which allocates tests both among herds and within herds. Finding the optimal allocation of tests is computationally difficult, so some surveillance programs simply seek an approximate solution. We developed a search algorithm to find the optimal allocation of tests by iteratively searching for adjustments to the test allocation that yielded marginal improvements in system sensitivity. We digitally generated 21 herds of various sizes, evenly divided among three regions that differed in relative risk. We then analyzed 29 scenarios that differed in disease and testing characteristics. We also analyzed a Chronic Wasting Disease (CWD) surveillance effort for 23 elk game management units of various sizes that were spread across three regions in Arizona, USA. We compared our marginal sensitivity approach to two other strategies for approximating the optimal distribution of tests: allocating the same number of tests to all herds selected for testing, and allocating tests so that all herds selected for testing achieve the same sensitivity. Across analysis scenarios, we found that low prevalence, high relative risk, a small budget, or high overhead costs were best addressed by concentrating tests in large, high-risk herds. When we expect multiple herds to be infected, the optimal allocation of tests depended on how we expected the cases to be distributed. Across the analyzed scenarios, our marginal sensitivity approach was most efficient, with alternative strategies requiring 0-228 % more tests to achieve the same sensitivity. For CWD in Arizona, we found the potential to double system sensitivity, given a population design prevalence of 0.16 %, from 35.8 % to 70.5 %, although social and budgetary considerations would likely constrain changes to the current allocation of tests. The marginal sensitivity approach we developed has the potential to improve disease surveillance, especially when a population includes a limited number of herds that differ in size. An important limitation of our approach is that computer runtimes could become unacceptably long for a population with many herds.

Effect of Canine Parvovirus and Canine Distemper Virus on the Mexican Wolf (Canis lupus baileyi) Population in the USA

Mexican wolves (Canis lupus baileyi), classified as probably extinct in the wild in Mexico and endangered in the US, were reintroduced into Arizona in 1998. We combined annual serologic testing results from samples collected between 2003 and 2016 from 108 wolves and known survival data from 118 wolves born in the recovery area from 2003 to 2014 to evaluate whether exposure to canine distemper virus (CDV) or canine parvovirus (CPV) was associated with a greater risk of mortality before 2 yr of age. We used mixed-effects logistic regression to estimate the effect of CDV and CPV on the probability of mortality. Annual seroprevalence rates for CDV and CPV ranged from 0% to 62% and from 33% to 100%, respectively (median, 14.2% and 90.3%, respectively). The covariate, age at testing, had a negative effect on mortality, indicating that younger animals had lower survival, whereas sex had little effect on mortality. The best-supported model excluded any effect of CPV or CDV on death before 2 yr old at both the pack and individual level. Although our analysis did not detect an effect of these viruses on mortality before 2 yr old, CDV was later identified as the cause of mortality in two individuals in 2017. Additional information is needed to assess the impact of these diseases on Mexican wolves.

Partitioning global change: Assessing the relative importance of changes in climate and land cover for changes in avian distribution

Understanding the relative impact of climate change and land cover change on changes in avian distribution has implications for the future course of avian distributions and appropriate management strategies. Due to the dynamic nature of climate change, our goal was to investigate the processes that shape species distributions, rather than the current distributional patterns. To this end, we analyzed changes in the distribution of Eastern Wood Pewees (Contopus virens) and Red-eyed Vireos (Vireo olivaceus) from 1997 to 2012 using Breeding Bird Survey data and dynamic correlated-detection occupancy models. We estimated the local colonization and extinction rates of these species in relation to changes in climate (hours of extreme temperature) and changes in land cover (amount of nesting habitat). We fit six nested models to partition the deviance explained by spatial and temporal components of land cover and climate. We isolated the temporal components of environmental variables because this is the essence of global change. For both species, model fit was significantly improved when we modeled vital rates as a function of spatial variation in climate and land cover. Model fit improved only marginally when we added temporal variation in climate and land cover to the model. Temporal variation in climate explained more deviance than temporal variation in land cover, although both combined only explained 20% (Eastern Wood Pewee) and 6% (Red-eyed Vireo) of temporal variation in vital rates. Our results showing a significant correlation between initial occupancy and environmental covariates are consistent with biological expectation and previous studies. The weak correlation between vital rates and temporal changes in covariates indicated that we have yet to identify the most relevant components of global change influencing the distributions of these species and, more importantly, that spatially significant covariates are not necessarily driving temporal shifts in avian distributions.

Accounting for imperfect detection of groups and individuals when estimating abundance

If animals are independently detected during surveys, many methods exist for estimating animal abundance despite detection probabilities <1. Common estimators include double‐observer models, distance sampling models and combined double‐observer and distance sampling models (known as mark‐recapture‐distance‐sampling models; MRDS). When animals reside in groups, however, the assumption of independent detection is violated. In this case, the standard approach is to account for imperfect detection of groups, while assuming that individuals within groups are detected perfectly. However, this assumption is often unsupported. We introduce an abundance estimator for grouped animals when detection of groups is imperfect and group size may be under‐counted, but not over‐counted. The estimator combines an MRDS model with an N‐mixture model to account for imperfect detection of individuals. The new MRDS‐Nmix model requires the same data as an MRDS model (independent detection histories, an estimate of distance to transect, and an estimate of group size), plus a second estimate of group size provided by the second observer. We extend the model to situations in which detection of individuals within groups declines with distance. We simulated 12 data sets and used Bayesian methods to compare the performance of the new MRDS‐Nmix model to an MRDS model. Abundance estimates generated by the MRDS‐Nmix model exhibited minimal bias and nominal coverage levels. In contrast, MRDS abundance estimates were biased low and exhibited poor coverage. Many species of conservation interest reside in groups and could benefit from an estimator that better accounts for imperfect detection. Furthermore, the ability to relax the assumption of perfect detection of individuals within detected groups may allow surveyors to re‐allocate resources toward detection of new groups instead of extensive surveys of known groups. We believe the proposed estimator is feasible because the only additional field data required are a second estimate of group size.

Estimating indices of range shifts in birds using dynamic models when detection is imperfect

There is intense interest in basic and applied ecology about the effect of global change on current and future species distributions. Projections based on widely used static modeling methods implicitly assume that species are in equilibrium with the environment and that detection during surveys is perfect. We used multiseason correlated detection occupancy models, which avoid these assumptions, to relate climate data to distributional shifts of Louisiana Waterthrush in the North American Breeding Bird Survey (BBS) data. We summarized these shifts with indices of range size and position and compared them to the same indices obtained using more basic modeling approaches. Detection rates during point counts in BBS surveys were low, and models that ignored imperfect detection severely underestimated the proportion of area occupied and slightly overestimated mean latitude. Static models indicated Louisiana Waterthrush distribution was most closely associated with moderate temperatures, while dynamic occupancy models indicated that initial occupancy was associated with diurnal temperature ranges and colonization of sites was associated with moderate precipitation. Overall, the proportion of area occupied and mean latitude changed little during the 1997-2013 study period. Near-term forecasts of species distribution generated by dynamic models were more similar to subsequently observed distributions than forecasts from static models. Occupancy models incorporating a finite mixture model on detection - a new extension to correlated detection occupancy models - were better supported and may reduce bias associated with detection heterogeneity. We argue that replacing phenomenological static models with more mechanistic dynamic models can improve projections of future species distributions. In turn, better projections can improve biodiversity forecasts, management decisions, and understanding of global change biology.

The effect of call libraries and acoustic filters on the identification of bat echolocation

Quantitative methods for species identification are commonly used in acoustic surveys for animals. While various identification models have been studied extensively, there has been little study of methods for selecting calls prior to modeling or methods for validating results after modeling. We obtained two call libraries with a combined 1556 pulse sequences from 11 North American bat species. We used four acoustic filters to automatically select and quantify bat calls from the combined library. For each filter, we trained a species identification model (a quadratic discriminant function analysis) and compared the classification ability of the models. In a separate analysis, we trained a classification model using just one call library. We then compared a conventional model assessment that used the training library against an alternative approach that used the second library. We found that filters differed in the share of known pulse sequences that were selected (68 to 96%), the share of non-bat noises that were excluded (37 to 100%), their measurement of various pulse parameters, and their overall correct classification rate (41% to 85%). Although the top two filters did not differ significantly in overall correct classification rate (85% and 83%), rates differed significantly for some bat species. In our assessment of call libraries, overall correct classification rates were significantly lower (15% to 23% lower) when tested on the second call library instead of the training library. Well-designed filters obviated the need for subjective and time-consuming manual selection of pulses. Accordingly, researchers should carefully design and test filters and include adequate descriptions in publications. Our results also indicate that it may not be possible to extend inferences about model accuracy beyond the training library. If so, the accuracy of acoustic-only surveys may be lower than commonly reported, which could affect ecological understanding or management decisions based on acoustic surveys.

Tree structure and cavity microclimate: implications for bats and birds

It is widely assumed that tree cavity structure and microclimate affect cavity selection and use in cavity-dwelling bats and birds. Despite the interest in tree structure and microclimate, the relationship between the two has rarely been quantified. Currently available data often comes from artificial structures that may not accurately represent conditions in natural cavities. We collected data on tree cavity structure and microclimate from 45 trees in five cypress-gum swamps in the Coastal Plain of Georgia in the United States in 2008. We used hierarchical linear models to predict cavity microclimate from tree structure and ambient temperature and humidity, and used Aikaike's information criterion to select the most parsimonious models. We found large differences in microclimate among trees, but tree structure variables explained <28% of the variation, while ambient conditions explained >80% of variation common to all trees. We argue that the determinants of microclimate are complex and multidimensional, and therefore cavity microclimate cannot be deduced easily from simple tree structures. Furthermore, we found that daily fluctuations in ambient conditions strongly affect microclimate, indicating that greater weather fluctuations will cause greater differences among tree cavities.

Simple syllabic calls accompany discrete behavior patterns in captive Pteronotus parnellii: an illustration of the motivation-structure hypothesis

Mustached bats, Pteronotus parnellii, are highly social and vocal. Individuals of this species roost in tight clusters, and emit an acoustically rich repertoire of calls whose behavioral significance is largely unknown. We recorded their social and vocal behaviors within a colony housed under semi-natural conditions. We also quantified the spatial spread of each bat's roosting location and discovered that this was relatively fixed and roughly confined to an individual's body width. The spatial precision in roosting was accompanied by an equally remarkable match between specific vocalizations and well-timed, discrete, identifiable postures/behaviors, as revealed by logistic regression analysis. The bodily behaviors included crouching, marking, yawning, nipping, flicking, fighting, kissing, inspecting, and fly-bys. Two echolocation-like calls were used to maintain spacing in the colony, two noisy broadband calls were emitted during fights, two tonal calls conveyed fear, and another tonal call signaled appeasement. Overall, the results establish that mustached bats exhibit complex social interactions common to other social mammals. The correspondence of relatively low frequency and noisy, broadband calls with aggression, and of tonal, high frequency calls with fear supports Morton's Motivation-Structure hypothesis, and establishes a link between motivation and the acoustic structure of social calls emitted by mustached bats.

Molecular evidence of field cancerization in a patient with 7 tumors of the aerodigestive tract

Exposure of the mucosa of the upper aerodigestive tract to carcinogens can induce genetic changes resulting in various independent clones of neoplastic growth, a concept defined as "field cancerization." The risk of developing multiple tumors in this compartment of the body is well established. We studied 6 distinct tumors of the upper aerodigestive tract of a single patient for loss of heterozygosity (LOH), microsatellite instability (MSI), p53 mutations, and K-ras codon 12 point mutations. We detected a unique pattern of LOH and p53 mutations in all 6 tumors. No tumor showed a K-ras mutation or MSI. The results support the mechanism of "field cancerization" and illustrate the potential power of molecular techniques to elucidate pathogenesis.

Alterations of the p53 tumor-suppressor gene and K-ras oncogene in perihilar cholangiocarcinomas from a high-incidence area

We observed a clustering of cholangiocarcinoma in a part of West Virginia. We analyzed the frequency and type of alterations in the p53 tumor-suppressor gene and the K-ras oncogene to determine whether cholangiocarcinomas from this high-incidence area differ from other cholangiocarcinomas at the molecular level. We studied 12 carcinomas of patients from the high-incidence area (West Virginia group), and 15 carcinomas of patients from nearby states (non-West Virginia group). Over-expression of the p53 gene product, accompanying most mutations in the p53 gene, was determined by immunohistochemistry. p53 sequence analysis of exons 5, 6, 7, and 8 of the p53-immunohistochemical-positive carcinomas was also performed. K-ras codon 12 mutations were detected by the polymerase chain reaction and allele-specific oligonucleotide hybridization. Significantly more cholangiocarcinomas from the West Virginia group were p53-immunohistochemical-positive than from the non-West Virginia group (67% vs. 20%; p < 0.05). p53 mutations did not differ in the 2 groups in respect to site or specific type. No differences were found between the 2 groups regarding K-ras mutations (17% vs. 27%). Although the higher frequency of p53-immunohistochemical positivity in the West Virginia group may reflect a different etiology of these cholangiocarcinomas, explaining the high incidence in this area, results of p53 sequence analysis were not different in the West Virginia group. The high incidence may be explained by difference in carcinogenic dose or a different etiology not reflected in p53 or K-ras alterations.

Alterations of the p53 tumor-suppressor gene and K-ras oncogene in perihilar cholangiocarcinomas from a high-incidence area

We observed a clustering of cholangiocarcinoma in a part of West Virginia. We analyzed the frequency and type of alterations in the p53 tumor-suppressor gene and the K-ras oncogene to determine whether cholangiocarcinomas from this high-incidence area differ from other cholangiocarcinomas at the molecular level. We studied 12 carcinomas of patients from the high-incidence area (West Virginia group), and 15 carcinomas of patients from nearby states (non-West Virginia group). Over-expression of the p53 gene product, accompanying most mutations in the p53 gene, was determined by immunohistochemistry. p53 sequence analysis of exons 5, 6, 7, and 8 of the p53-immunohistochemical-positive carcinomas was also performed. K-ras codon 12 mutations were detected by the polymerase chain reaction and allele-specific oligonucleotide hybridization. Significantly more cholangiocarcinomas from the West Virginia group were p53-immunohistochemical-positive than from the non-West Virginia group (67% vs. 20%; p < 0.05). p53 mutations did not differ in the 2 groups in respect to site or specific type. No differences were found between the 2 groups regarding K-ras mutations (17% vs. 27%). Although the higher frequency of p53-immunohistochemical positivity in the West Virginia group may reflect a different etiology of these cholangiocarcinomas, explaining the high incidence in this area, results of p53 sequence analysis were not different in the West Virginia group. The high incidence may be explained by difference in carcinogenic dose or a different etiology not reflected in p53 or K-ras alterations.

p53 alterations in atypical alveolar hyperplasia of the human lung

Atypical alveolar hyperplasia (AAH) is a potential precursor lesion from which lung adenocarcinomas arise and may be a good target for studying the early events of lung tumorigenesis. We have previously shown that AAHs are neoplastic epithelial proliferations that often harbor activating mutations of the K-ras oncogene. In the current study, we examined a spectrum of AAHs to determine the frequency and timing of p53 alterations in lung tumorigenesis. We analyzed 37 AAHs and their paired overt lung neoplasms for p53 protein accumulation using the monoclonal antibody DO7. DNA sequence analysis of the p53 gene was performed on those cases demonstrating p53 protein accumulation. AAHs were classified as low-grade, high-grade, or AAH-like carcinoma based on cytoarchitectural features. Accumulation of the p53 protein was found in none (0%) of 20 low-grade AAHs, in 1 (9%) of 11 high-grade AAHs, and in three (50%) of six AAH-like carcinomas. There was a statistically significant trend toward p53 accumulation with increasing grade of the AAHs. A missense mutation in exon 7 of the p53 gene was found in 1 AAH-like carcinoma, whereas mutations in exons 5 through 8 could not be detected in the other three AAHs with p53 protein accumulation. Three of the paired overt carcinomas harbored p53 mutations that were not present in the AAHs. Alterations of p53 do not appear to be common events in AAHs, especially when these lesions exhibit low-grade cytoarchitectural features. Alterations of p53, however, are more frequent at the level of AAH-like carcinoma and may be associated with the transition from a benign to a malignant proliferation of pneumocytes.

Mutational analysis of the P16-binding domain of cyclin-dependent kinase 4 in tumors in the head region of the pancreas

Alterations in genes involved in cell cycle regulation are common in many tumor types. In pancreatic adenocarcinomas, inactivating mutations in the CDKN2 gene, encoding the cyclin-dependent kinase inhibitor p16, are frequently observed. CDKN2 mutations have also been identified in the germline of 50% of patients with hereditary melanoma. Interestingly, such patients also have an increased risk for pancreatic cancers. In melanoma-prone kindreds with CDKN2 wild-type status, a mutation in one of the targets of p16, cyclin-dependent kinase 4 (CDK4) was reported, which abolishes p16 inhibition. To test the possible involvement of CDK4 mutations in pancreatic carcinoma, we analyzed sequence alterations in the p16-binding domain of CDK4 in DNA isolated from 32 tumors in the head region of the pancreas. Alterations in the CDK4 region between codon 1 and codon 56 were not observed in any of the tumors. Our results do not support disruption of the p16 pathway through CDK4 mutation as an oncogenic mechanism in pancreatic head tumorigenesis.

Multiple hyperplastic polyps in the stomach: evidence for clonality and neoplastic potential

The origin and neoplastic potential of gastric epithelial polyps remains an area of great interest, and treatment choices are a topic of controversy. This report describes a patient diagnosed with three concurrent hyperplastic gastric polyps that were studied for genetic alterations. The polyps were investigated for alterations in the K-ras oncogene and the p53 tumor suppressor gene and for p21WAF1/Cip1 and MDM2 protein overexpression. In addition, loss of heterozygosity at several loci that are frequently involved in human cancer was analyzed, microsatellite instability, a hallmark of the "mutator" phenotype, was determined, and Epstein-Barr virus infection was investigated. All separate areas from the three independent polyps harbored the same activating point mutation in codon 12 of the K-ras oncogene, indicating a clonal origin. DNA sequence alterations in p53 were not found, although high p53 protein levels could be shown by immunohistochemistry in areas of carcinoma within the largest polyp. No alterations in any of the other molecular markers were observed. The results strongly favor a clonal origin of the three independent gastric polyps and support the notion that these hyperplastic polyps may carry a risk for malignancy.

Potential false-positive results with antigen enhancement for immunohistochemistry of the p53 gene product in colorectal neoplasms

Immunohistochemistry (IHC) for intranuclear p53 gene product is a simple, routine alternative to molecular genetic analysis of the p53 gene. Several methods for antigen enhancement are currently in use for IHC. This study evaluates the effect of extreme antigen enhancement for p53, using a monoclonal antibody (DO7) and a polyclonal antibody (CM1). The cases studied were five colorectal carcinomas, two specimens of normal colorectal mucosa, and four colorectal carcinomas with genetic alterations which are expected to preclude p53 gene product expression, namely mutation to a STOP codon in the p53 gene detected by denaturing gradient gel electrophoresis with subsequent sequencing and allelic loss of 17p in the region where p53 is located, detected by restriction fragment length polymorphism analysis. The findings suggest that extreme antigen enhancement may cause false-positive results with a distinct nuclear staining pattern when MAb DO7 is used as a primary antibody. It is concluded that all antigen enhancement methods should be thoroughly tested to evaluate their validity and that there may be a limit to the extent to which antigen enhancement can be applied in IHC for p53 protein.

Detection of K-ras mutations in mucinous pancreatic duct hyperplasia from a patient with a family history of pancreatic carcinoma

Mutations in the K-ras oncogene and in the p53 tumor suppressor gene are commonly identified in sporadic cases of pancreatic adenocarcinoma. Although these genes might serve as useful markers for early diagnosis of pancreatic carcinoma in patients at risk for the development of this disease, familial pancreatic carcinomas have not been studied for these mutations. We recently had the opportunity to examine a pancreas prophylactically removed from a patient with a strong family history of pancreatic carcinoma. This gave us the unique opportunity to study the early events in the development of familial adenocarcinoma of the pancreas. Histopathological examination of the pancreas revealed multifocal papillary and nonpapillary mucinous duct hyperplasia. Seven of these foci were microdissected and analyzed for K-ras and p53 mutations. The K-ras mutations were detected by combined mutant-enriched polymerase chain reaction-restriction fragment length polymorphism analysis and characterized further by allele-specific oligonucleotide hybridization. Five of the seven duct lesions harbored activating point mutations in codon 12 of K-ras; a G to A transition was found in four and a G to C transversion in one. In contrast, these lesions did not harbor detectable p53 mutations as determined by denaturing gradient gel electrophoresis of exons 5 to 8, nor was there overexpression of the p53 protein as determined by immunohistochemistry. These findings suggest that mutations in K-ras represent an early event in the pathogenesis of pancreatic carcinoma. In addition, monitoring of patients with a strong family history of pancreatic carcinoma for K-ras mutations may identify patients at risk for the development of invasive carcinoma.

Extrapulmonary pneumocystosis: clinical features in human immunodeficiency virus infection

Pneumocystis carinii infection is reported with increasing frequency as a cause of disease outside of the respiratory tract in patients with human immunodeficiency virus (HIV) infection. Extrapulmonary pneumocystosis is not limited to patients in any discrete risk group for HIV infection. Patients with HIV infection who develop extrapulmonary pneumocystosis frequently do not have concurrent P. carinii pneumonia. Signs and symptoms of extrapulmonary pneumocystosis are nonspecific but when present are frequently referable to the tissues or organs involved. Extrapulmonary pneumocystosis can be diagnosed by examination of tissue biopsies from affected sites using standard histologic techniques. Therapy with antimicrobial agents used to treat P. carinii pneumonia has been effective in some patients. An association between use of aerosolized pentamidine for prevention of P. carinii pneumonia and development of extrapulmonary pneumocystosis has been suggested but remains unconfirmed. Other factors such as the use of zidovudine and duration of immunodeficiency may also be important to the pathogenesis of extrapulmonary pneumocystosis. Further studies are needed to better identify risk factors that may predispose patients to the development of extrapulmonary pneumocystosis.

A survey of adolescents with epilepsy

Thirty-four adolescents with epilepsy, controls matched for age and sex (A) and controls matched for age, sex and general ability (B), were studied. The adolescents with epilepsy were more likely to arrive at school by car or taxi and to have more difficult behaviour in class. Competitive sports were less popular with them and significantly fewer anticipated ever driving a car. Illness and parental marital problems were not a feature of their families. Their comprehension of reading material was significantly poorer than that of control group A. Within the group, the lowest over-all reading scores were found in children with myoclonic seizures, partial seizures with secondary generalisation, or generalised tonic-clonic seizures; and in those whose EEG findings included two-per-second spike and wave, photosensitivity, generalised slow waves, or generalised spike and wave of non-specific frequency. Right focal slow waves, sharp waves and spikes on EEG were associated with problems of comprehension, even when the over-all reading score was acceptable.

Sensitivity of treponemal tests for detecting prior treated syphilis during human immunodeficiency virus infection

To evaluate the sensitivity of treponemal tests as a marker of prior syphilis in individuals with human immunodeficiency virus (HIV) infection, the syphilis serology of 109 homosexual men with a documented history of treated syphilis was compared with records of prior results and confirmed on stored serum samples. None of the HIV-seronegative individuals lost reactivity to a treponemal test, whereas 7% of the seropositive asymptomatic individuals and 38% of those with symptomatic HIV infection had loss of reactivity. Symptomatic HIV infection was associated with loss of reactivity, as a T4 lymphocyte count less than 200 X 10(6)/1, a T4-to-T8 ratio less than 0.6, a single prior episode of syphilis, and a low VDRL titer at the time of the last documented episode of syphilis. Although no conclusions can be drawn about the sensitivity of treponemal tests in patients with active syphilis and HIV infection, these data suggest that treponemal tests may not identify those previously infected with Treponema pallidum.

Sequential serological responses to Aspergillus fumigatus in patients with cystic fibrosis. Use of antigen 'stretching' to delineate IgG and IgE activity

Immunogens from Aspergillus fumigatus were fractionated on the basis of molecular weight. Nine fractions ranging from 900 to 10 kDa were used in ELISA and in a radioallergosorbent test (RAST) with sera from cases of allergic bronchopulmonary aspergillosis (ABPA) and from cystic fibrosis (CF) patients with ABPA or other Aspergillus involvement and compared with control subjects. The profile of IgG reactivity to the nine fractions did not vary substantially for all Aspergillus-involved groups producing peaks at greater than 900 kD and 170 kD whereas the profile for control subjects had a peak at greater than 900 kD only. The IgE profile for CF patients with ABPA did not differ from the profile of the RAST-positive CF patients without ABPA and provided only one peak of activity at 24 kD. Recovery from an episode of ABPA in CF patients was accompanied by a fall in both IgG and IgE antibody levels to all nine fractions, whereas increases in IgG and IgE to all fractions were seen during an episode of ABPA. Although there was an exaggerated IgG increase to antigens in the 43-170 kD range during ABPA, a meaningful increase was also observed to unfractionated A. fumigatus antigen preparations. With IgE in one detailed study the 24-kD fraction provided a better indication of Aspergillus involvement than the unfractionated A. fumigatus antigens. Sequential studies of IgG and IgE levels were not able to predict an episode of ABPA but were useful in conjunction with clinical assessment in following the course of the illness.

Pulmonary diagnostic evaluation in patients suspected of having an HIV-related disease

The wide range of pulmonary infections associated with human immunodeficiency virus (HIV)-seropositivity, coupled with the possible presence of HIV-related neoplasms and non-HIV-related pulmonary processes, requires that most patients who are known to be or suspected of being HIV-seropositive should undergo a thorough diagnostic evaluation. This usually should include a screening evaluation that includes history, physical examination, screening laboratory tests, chest radiography, and arterial blood gas measurements. Pulmonary function testing and lung scanning also may be sensitive in screening, although these and the other procedures are nonspecific. Specific infectious organisms, particularly Pneumocystis carinii, may be identified through examination of induced sputum and by bronchoscopic procedures, including bronchoalveolar lavage and transbronchial biopsy. Open lung biopsy is not a routine part of the diagnostic evaluation. Although detection of recurrent episodes of pneumonia due to P carinii is difficult, empiric diagnosis and treatment of this disorder should be employed primarily when specific diagnostic techniques are unavailable or are refused.

Diagnosis of pulmonary diseases

A broad spectrum of lung disease occurs in association with HIV infection. Included are both infectious and neoplastic processes and idiopathic disorders. To insure prompt, accurate, and efficient diagnosis, a logical, staged sequence of tests should be applied. Chest films and, in some instances, pulmonary function tests and gallium-67 citrate lung scans serve to provide objective indications of lung disease. Each of these tests is sensitive but nonspecific. Specific infecting organisms, particularly P. carinii, can be identified by examining sputum induced by inhalation of 3 per cent saline. Bronchoscopic procedures, including BAL and TBB, are highly sensitive and should be performed in patients having nondiagnostic sputum examinations. Tests involving antigen and antibody detection are of little use in the evaluation of individual patients. Detection of recurrent episodes of PCP is difficult because abnormalities in the usual screening tests may be residual from previous episodes. Finding P. carinii in sputum or bronchoscopic specimens soon (within 2 to 3 months) after a confirmed episode of PCP likely represents residual organisms rather than recrudescence of the infection. Empiric diagnosis of P. carinii should be employed only in limited circumstances when specific diagnostic studies are not available, are contraindicated, or are refused.

Juvenile myoclonic epilepsy

The clinical and electroencephalographic features of 10 adolescents with juvenile myoclonic epilepsy are presented. The mean age on onset was 12.3 years. Myoclonic jerks, predominantly on awakening, occurred in all 10 and were associated with infrequent generalised tonic-clonic seizures in nine. Five had first degree relatives with seizures. The neurodevelopmental status was normal in eight and social integration good in seven. Waking interictal electroencephalograms showed normal background activity in nine, polyspike and wave in six, and single spike and wave in eight. Four were photosensitive. Failure to respond to other antiepileptic drugs was usual, but valproate monotherapy resulted in good or complete seizure control. Juvenile myoclonic epilepsy is a well defined clinical entity that responds well to valproate and is usually associated with a good outlook.