Longitudinal social contact data analysis: insights from 2 years of data collection in Belgium during the COVID-19 pandemic

BACKGROUND

During the COVID-19 pandemic, the CoMix study, a longitudinal behavioral survey, was designed to monitor social contacts and public awareness in multiple countries, including Belgium. As a longitudinal survey, it is vulnerable to participants' "survey fatigue", which may impact inferences.

METHODS

A negative binomial generalized additive model for location, scale, and shape (NBI GAMLSS) was adopted to estimate the number of contacts reported between age groups and to deal with under-reporting due to fatigue within the study. The dropout process was analyzed with first-order auto-regressive logistic regression to identify factors that influence dropout. Using the so-called next generation principle, we calculated the effect of under-reporting due to fatigue on estimating the reproduction number.

RESULTS

Fewer contacts were reported as people participated longer in the survey, which suggests under-reporting due to survey fatigue. Participant dropout is significantly affected by household size and age categories, but not significantly affected by the number of contacts reported in any of the two latest waves. This indicates covariate-dependent missing completely at random (MCAR) in the dropout pattern, when missing at random (MAR) is the alternative. However, we cannot rule out more complex mechanisms such as missing not at random (MNAR). Moreover, under-reporting due to fatigue is found to be consistent over time and implies a 15-30% reduction in both the number of contacts and the reproduction number ([Formula: see text]) ratio between correcting and not correcting for under-reporting. Lastly, we found that correcting for fatigue did not change the pattern of relative incidence between age groups also when considering age-specific heterogeneity in susceptibility and infectivity.

CONCLUSIONS

CoMix data highlights the variability of contact patterns across age groups and time, revealing the mechanisms governing the spread/transmission of COVID-19/airborne diseases in the population. Although such longitudinal contact surveys are prone to the under-reporting due to participant fatigue and drop-out, we showed that these factors can be identified and corrected using NBI GAMLSS. This information can be used to improve the design of similar, future surveys.

Attitudes towards booster, testing and isolation, and their impact on COVID-19 response in winter 2022/2023 in France, Belgium, and Italy: a cross-sectional survey and modelling study

Background

European countries are focusing on testing, isolation, and boosting strategies to counter the 2022/2023 winter surge due to SARS-CoV-2 Omicron subvariants. However, widespread pandemic fatigue and limited compliance potentially undermine mitigation efforts.

Methods

To establish a baseline for interventions, we ran a multicountry survey to assess respondents’ willingness to receive booster vaccination and comply with testing and isolation mandates. Integrating survey and estimated immunity data in a branching process epidemic spreading model, we evaluated the effectiveness and costs of current protocols in France, Belgium, and Italy to manage the winter wave.

Findings

The vast majority of survey participants (N = 4594) was willing to adhere to testing (>91%) and rapid isolation (>88%) across the three countries. Pronounced differences emerged in the declared senior adherence to booster vaccination (73% in France, 94% in Belgium, 86% in Italy). Epidemic model results estimate that testing and isolation protocols would confer significant benefit in reducing transmission (17–24% reduction, from R = 1.6 to R = 1.3 in France and Belgium, to R = 1.2 in Italy) with declared adherence. Achieving a mitigating level similar to the French protocol, the Belgian protocol would require 35% fewer tests (from 1 test to 0.65 test per infected person) and avoid the long isolation periods of the Italian protocol (average of 6 days vs. 11). A cost barrier to test would significantly decrease adherence in France and Belgium, undermining protocols’ effectiveness.

Interpretation

Simpler mandates for isolation may increase awareness and actual compliance, reducing testing costs, without compromising mitigation. High booster vaccination uptake remains key for the control of the winter wave.

Funding

The 10.13039/501100000780European Commission, ANRS–Maladies Infectieuses Émergentes, the Agence Nationale de la Recherche, the Chaires Blaise Pascal Program of the Île-de-France region.

Utility of a machine-guided tool for assessing risk behaviour associated with contracting HIV in three sites in South Africa

Introduction

Digital data collection and the associated mobile health technologies have allowed for the recent exploration of artificial intelligence as a tool for combatting the HIV epidemic. Machine learning has been found to be useful both in HIV risk prediction and as a decision support tool for guiding pre-exposure prophylaxis (PrEP) treatment. This paper reports data from two sequential studies evaluating the viability of using machine learning to predict the susceptibility of adults to HIV infection using responses from a digital survey deployed in a high burden, low-resource setting.

Methods

1036 and 593 participants were recruited across two trials. The first trial was a cross-sectional study in one location and the second trial was a cohort study across three trial sites. The data from the studies were merged, partitioned using standard techniques, and then used to train and evaluate multiple different machine learning models and select and evaluate a final model. Variable importance estimates were calculated using the PIMP and SHAP methodologies.

Results

Characteristics associated with HIV were consistent across both studies. Overall, HIV positive patients had a higher median age (34 [IQR: 29-39] vs 26 [IQR 22-33], p < 0.001), and were more likely to be female (155/703 [22%] vs 107/927 [12%], p < 0.001). HIV positive participants also had more commonly gone a year or more since their last HIV test (183/262 [70%] vs 540/1368 [39%], p < 0.001) and were less likely to report consistent condom usage (113/262 [43%] vs 758/1368 [55%], p < 0.001). Patients who reported TB symptoms were more likely to be HIV positive. The trained models had accuracy values (AUROCs) ranging from 78.5% to 82.8%. A boosted tree model performed best with a sensitivity of 84% (95% CI 72-92), specificity of 71% (95% CI 67-76), and a negative predictive value of 95% (95% CI 93-96) in a hold-out dataset. Age, duration since last HIV test, and number of male sexual partners were consistently three of the four most important variables across both variable importance estimates.

Conclusions

This study has highlighted the synergies present between mobile health and machine learning in HIV. It has been demonstrated that a viable ML model can be built using digital survey data from an low-middle income setting with potential utility in directing health resources.

Epitweetr: Early warning of public health threats using Twitter data

BackgroundThe European Centre for Disease Prevention and Control (ECDC) systematically collates information from sources to rapidly detect early public health threats. The lack of a freely available, customisable and automated early warning tool using data from Twitter prompted the ECDC to develop epitweetr, which collects, geolocates and aggregates tweets generating signals and email alerts.AimThis study aims to compare the performance of epitweetr to manually monitoring tweets for the purpose of early detecting public health threats.MethodsWe calculated the general and specific positive predictive value (PPV) of signals generated by epitweetr between 19 October and 30 November 2020. Sensitivity, specificity, timeliness and accuracy and performance of tweet geolocation and signal detection algorithms obtained from epitweetr and the manual monitoring of 1,200 tweets were compared.ResultsThe epitweetr geolocation algorithm had an accuracy of 30.1% at national, and 25.9% at subnational levels. The signal detection algorithm had 3.0% general PPV and 74.6% specific PPV. Compared to manual monitoring, epitweetr had greater sensitivity (47.9% and 78.6%, respectively), and reduced PPV (97.9% and 74.6%, respectively). Median validation time difference between 16 common events detected by epitweetr and manual monitoring was -48.6 hours (IQR: -102.8 to -23.7).ConclusionEpitweetr has shown sufficient performance as an early warning tool for public health threats using Twitter data. Since epitweetr is a free, open-source tool with configurable settings and a strong automated component, it is expected to increase in usability and usefulness to public health experts.

SOCRATES-CoMix: a platform for timely and open-source contact mixing data during and in between COVID-19 surges and interventions in over 20 European countries

BACKGROUND

SARS-CoV-2 dynamics are driven by human behaviour. Social contact data are of utmost importance in the context of transmission models of close-contact infections.

METHODS

Using online representative panels of adults reporting on their own behaviour as well as parents reporting on the behaviour of one of their children, we collect contact mixing (CoMix) behaviour in various phases of the COVID-19 pandemic in over 20 European countries. We provide these timely, repeated observations using an online platform: SOCRATES-CoMix. In addition to providing cleaned datasets to researchers, the platform allows users to extract contact matrices that can be stratified by age, type of day, intensity of the contact and gender. These observations provide insights on the relative impact of recommended or imposed social distance measures on contacts and can inform mathematical models on epidemic spread.

CONCLUSION

These data provide essential information for policymakers to balance non-pharmaceutical interventions, economic activity, mental health and wellbeing, during vaccine rollout.

Task-related measures of short-interval intracortical inhibition and GABA levels in healthy young and older adults: A multimodal TMS-MRS study

Establishing the associations between magnetic resonance spectroscopy (MRS)-assessed gamma-aminobutyric acid (GABA) levels and transcranial magnetic stimulation (TMS)-derived ‘task-related’ modulations in GABA_A receptor-mediated inhibition and how these associations change with advancing age is a topic of interest in the field of human neuroscience. In this study, we identified the relationship between GABA levels and task-related modulations in GABA_A receptor-mediated inhibition in the dominant (left) and non-dominant (right) sensorimotor (SM) cortices. GABA levels were measured using edited MRS and task-related GABA_A receptor-mediated inhibition was measured using a short-interval intracortical inhibition (SICI) TMS protocol during the preparation and premotor period of a choice reaction time (CRT) task in 25 young (aged 18–33 years) and 25 older (aged 60–74 years) adults. Our results demonstrated that GABA levels in both SM voxels were lower in older adults as compared to younger adults; and higher SM GABA levels in the dominant as compared to the non-dominant SM voxel pointed to a lateralization effect, irrespective of age group. Furthermore, older adults showed decreased GABA_A receptor-mediated inhibition in the preparation phase of the CRT task within the dominant primary motor cortex (M1), as compared to young adults. Finally, results from an exploratory correlation analysis pointed towards positive relationships between MRS-assessed GABA levels and TMS-derived task-related SICI measures. However, after correction for multiple comparisons none of the correlations remained significant.

Age-Related Declines in Motor Performance are Associated With Decreased Segregation of Large-Scale Resting State Brain Networks

Aging is typically associated with substantial declines in motor functioning as well as robust changes in the functional organization of brain networks. Previous research has investigated the link between these 2 age-varying factors but examinations were predominantly limited to the functional organization within motor-related brain networks. Little is known about the relationship between age-related behavioral impairments and changes in functional organization at the whole brain (i.e., multiple network) level. This knowledge gap is surprising given that the decreased segregation of brain networks (i.e., increased internetwork connectivity) can be considered a hallmark of the aging process. Accordingly, we investigated the association between declines in motor performance across the adult lifespan (20-75 years) and age-related modulations of functional connectivity within and between resting state networks. Results indicated that stronger internetwork resting state connectivity observed as a function of age was significantly related to worse motor performance. Moreover, performance had a significantly stronger association with the strength of internetwork as compared with intranetwork connectivity, including connectivity within motor networks. These findings suggest that age-related declines in motor performance may be attributed to a breakdown in the functional organization of large-scale brain networks rather than simply age-related connectivity changes within motor-related networks.

How to reliably diagnose arterial hypertension: lessons from 24 h blood pressure monitoring

BACKGROUND

Hypertension is a common condition in modern society. As blood pressure fluctuates with time, a single blood pressure measurement is useless to diagnose hypertension. Nevertheless, no well-defined number of measurements is often used for this purpose. Diagnosis and therapeutic control of hypertension are therefore suboptimal.

OBJECTIVE

To determine the number and timing of measurements needed to give a trustworthy approximation of an individual's average blood pressure.

METHODS

In this observational study 306 clinically indicated 24h ABPM datasets were analysed. Hypertension was defined as a daytime blood pressure mean exceeding 135/85 mm Hg. Kappa coefficients determined the best time of day for measuring blood pressure. The optimal number of measurements was estimated using canonical correlation.

RESULTS

162 (53%) patients were diagnosed with hypertension. Kappa statistics indicated that measuring during the afternoon gave the best agreement with the 24h blood pressure mean (κ = 0.78). According to canonical correlation, about 8-10 blood pressure readings give enough information for hypertension diagnosis.

CONCLUSIONS

Eight to ten blood pressure measurements between 01:00 and 05:00 p.m. are sufficient to give a clinically useful approximation of the daytime mean blood pressure and therefore for diagnosing hypertension accurately. Future research should determine the ideal dispersion of measurements and include patient characteristics which could influence the required number and timing of measurements. These results may increase the future importance of telemonitoring in diagnosing hypertension.

Doubly robust pseudo-likelihood for incomplete hierarchical binary data

Missing data is almost inevitable in correlated-data studies. For non-Gaussian outcomes with moderate to large sequences, direct-likelihood methods can involve complex, hard-to-manipulate likelihoods. Popular alternative approaches, like generalized estimating equations, that are frequently used to circumvent the computational complexity of full likelihood, are less suitable when scientific interest, at least in part, is placed on the association structure; pseudo-likelihood (PL) methods are then a viable alternative. When the missing data are missing at random, Molenberghs et al. (2011, Statistica Sinica, 21,187–206) proposed a suite of corrections to the standard form of PL, taking the form of singly and doubly robust estimators. They provided the basis and exemplified it in insightful yet primarily illustrative examples. We here consider the important case of marginal models for hierarchical binary data, provide an effective implementation and illustrate it using data from an analgesic trial. Our doubly robust estimator is more convenient than the classical doubly robust estimators. The ideas are illustrated using a marginal model for a binary response, more specifically a Bahadur model.

Delayed HIV testing in internal medicine clinics - a missed opportunity

As HIV infection may be non-symptomatic for many years, many HIV-infected individuals are not aware of their infection. At a certain point in time non-specific symptoms may occur for which patients are likely be referred to internal medicine outpatient clinics. In the absence of systematic screening for HIV and in particular in patients who do not have classical risk factors for HIV, the diagnosis of HIV infection may easily be overlooked. In this manuscript it is illustrated that this diagnostic and therapeutic delay can lead to increased morbidity and mortality. Moreover, undiagnosed individuals are on average more likely to transmit HIV than diagnosed individuals. It is important for public health to identify people harbouring HIV infection, as this is expected to reduce the number of new infections. HIV infection should be considered a possible cause of unexplained symptoms in an early stage of the diagnostic process, in particular in patients with symptoms such as unexplained fever, lymphadenopathy or weight loss or in the presence of conditions suggestive of possible immune deficiency, regardless of the absence of risk factors.

Thrombotic thrombocytopenic purpura: a rare but potential life-threatening complication following ticlopidine administration

Thrombotic thrombocytopenic purpura (TTP) is a known, although rare, complication of ticlopidine treatment. It typically appears within the first days or weeks after initiation of therapy. We describe a case of TTP in a 75-year-old patient, due to ticlopidine, occurring three weeks after coronary stent implantation. The patient responded favourably to fresh frozen plasma exchanges. We are reporting this case to emphasize that prognosis depends on prompt diagnosis and early treatment, implying careful biochemical monitoring.

Randomized coronary patency trial of double-bolus recombinant staphylokinase versus front-loaded alteplase in acute myocardial infarction

One hundred two patients with evolving myocardial infarction of 6 hours' duration were given aspirin and intravenous heparin and randomly allocated to intravenous front-loaded, weight-adjusted rTPA administration over a 90-minute period (52 patients) or to two 15 mg doses of recombinant staphylokinase, 30 minutes apart (50 patients). Thrombolysis in Myocardial infarction (TIMI) perfusion grade 3 at 90 minutes was achieved in 68% (95% confidence interval, 55% to 81%) of patients treated with staphylokinase versus 57% (95% confidence interval, 43% to 72%) of patients treated with rTPA (p = not significant). Double-bolus staphylokinase was significantly more fibrin-specific than accelerated rTPA with residual fibrinogen at 90 minutes of 105% +/- 4.1% and 68% +/- 7.5%, respectively (p < 0.0001). Thirteen patients in each study group underwent angioplasty of the culprit coronary artery within the first 24 hours because of suboptimal recanalization (TIMI < 3). In the patients without prior coronary intervention, TIMI 3 at 24 hours was 100% after staphylokinase administration (n = 35) versus 79% after rTPA (n = 34) (p = 0.005). The distribution of inhospital events did not significantly differ between both groups. One patient receiving rTPA died in the hospital from ischemic stroke. Staphylokinase administration did not induce allergic reactions, but significant staphylokinase-neutralizing activity (> 5 micrograms/ml) and specific anti-staphylokinase IgG developed in 73% of patients after 2 weeks. Thus two 15 mg doses of staphylokinase induce early, complete, and sustained coronary artery patency at least as frequently as accelerated rTPA without associated fibrinogen degradation but with subsequent induction of circulating neutralizing antibodies.

Classification of normal and abnormal electrogastrograms using multilayer feedforward neural networks

A neural network approach is proposed for the automated classification of the normal and abnormal EGG. Two learning algorithms, the quasi-Newton and the scaled conjugate gradient method for the multilayer feedforward neural networks (MFNN), are introduced and compared with the error backpropagation algorithm. The configurations of the MFNN are determined by experiment. The raw EGG data, its power spectral data, and its autoregressive moving average (ARMA) modelling parameters are used as the input to the MFNN and compared with each other. Three indexes (the percent correct, sum-squared error and complexity per iteration) are used to evaluate the performance of each learning algorithm. The results show that the scaled conjugate gradient algorithm performs best, in that it is robust and provides a super-linear convergence rate. The power spectral representation and the ARMA modelling parameters of the EGG are found to be better types of the input to the network for this specific application, both yielding a percent correctness of 95% on the test set. Although the results are focused on the classification of the EGG, this paper should provide useful information for the classification of other biomedical signals.

Renal responses to exercise in heart and kidney transplant patients

There is a lack of information about renal responses in heart and kidney transplant patients after intense physical exercise. Eleven heart and ten kidney transplant recipients, as well as two control groups of healthy subjects, were given a maximum exercise test on a bicycle ergometer. One control group was also given a moderate load corresponding to the peak load of the kidney transplant group. Blood and urine samples were collected before and after exercise and assayed for lactate, creatinine, total protein, and albumin. The glomerular filtration rate remained stable at the end of exercise in the transplant patients, while there was a slight (17%) decrease in the control group. Albumin excretion rates after maximum exercise attained a mean of 237 micrograms.min-1 in the control group and a mean of 45 and 16 micrograms.min-1, respectively, in the heart and kidney groups. Postexercise proteinuria seemed to be related to the absolute intensity of the event, but kidney transplant patients showed a reduced effect as compared to heart transplant patients. We conclude that short-term, maximum exercise in heart and kidney transplant recipients is not detrimental to kidney function.

A randomized trial of recombinant staphylokinase versus alteplase for coronary artery patency in acute myocardial infarction. The STAR Trial Group

BACKGROUND

Recombinant staphylokinase (STAR) was shown recently to offer promise for coronary arterial thrombolysis in patients with evolving myocardial infarction. The present multicenter randomized open trial was designed to assess the thrombolytic efficacy, safety, and fibrin specificity of STAR relative to accelerated alteplase (recombinant tissue-type plasminogen activator [RTPA]).

METHODS AND RESULTS

One hundred patients with evolving myocardial infarction of < 6 hours' duration and with ST-segment elevation were allocated to accelerated and weight-adjusted RTPA over 90 minutes (52 patients) or to STAR (the first 25 patients to 10 mg and the next 23 patients to 20 mg given intravenously over 30 minutes). All patients received aspirin and intravenous heparin. The main end points were coronary artery patency and plasma fibrinogen levels at 90 minutes. Thrombolysis in Myocardial Infarction (TIMI) perfusion grade 3 at 90 minutes was achieved in 62% of STAR patients versus 58% of RTPA patients (risk ratio, 1.1; 95% CI, 0.76 to 1.5). With 10 mg STAR, TIMI grade 3 patency was 50% (risk ratio, 0.86; 95% CI, 0.54 to 1.4 versus RTPA); with 20 mg STAR, it was 74% (risk ratio, 1.3; 95% CI, 0.90 to 1.8 versus RTPA). Residual fibrinogen levels at 90 minutes were 118 +/- 47% (mean +/- SD) of baseline with STAR and 68 +/- 42% with RTPA (P < .0005). STAR therapy was not associated with an excess mortality or electric, hemorrhagic, mechanical, or allergic complications. However, patients developed antibody-mediated STAR-neutralizing activity from the second week after STAR treatment. As an addendum to the randomized study, 5 patients were given 40 mg STAR over 30 minutes, resulting in TIMI perfusion grade 3 at 90 minutes in 4 patients without fibrinogen breakdown (residual levels at 90 minutes of 105 +/- 8% of baseline).

CONCLUSIONS

STAR appears to be at least as effective for early coronary recanalization as and significantly more fibrin-specific than accelerated RTPA in patients with evolving myocardial infarction.

At equipotent doses, isradipine is better tolerated than amlodipine in patients with mild-to-moderate hypertension: a double-blind, randomized, parallel-group study

1. The objective of this double-blind parallel-group study was to compare the tolerability of isradipine and amlodipine, specifically, the side-effects known to be related to the use of dihydropyridine calcium antagonists. 2. A total of 205 patients with mild-to-moderate essential hypertension were randomized to receive either the sustained-release (SRO) formulation of isradipine (n = 103) or amlodipine (n = 102), both at dosages of 5 mg once daily. Blood pressure measurements were taken at the end of the dosing interval to assess the antihypertensive efficacy of the two drugs. 3. Adverse reactions were assessed in two ways: a) spontaneously reported adverse events were recorded and investigated in depth for severity, duration, relation to the study drug, and outcome; b) a questionnaire was used to elicit specific adverse reactions known to be related to the use of dihydropyridine calcium antagonists which were evaluated for severity, duration, relation to the study drug, and outcome. 4. After 6 weeks of active treatment, both isradipine and amlodipine reduced mean sitting systolic/diastolic blood pressure: from 165.1/100.1 to 145.2/89.7 mm Hg with isradipine; and from 164.1/100.6 to 145.7/90.5 mm Hg with amlodipine. There was no difference in antihypertensive effect between isradipine and amlodipine (95% CI: -3.73 to 4.73 and -1.89 to 3.49 for differences in systolic and diastolic blood pressure, respectively). 5. The number of patients spontaneously reporting adverse events was significantly higher (P = 0.02; 95% CI: 3.1 to 26.7%) with amlodipine (33.3%) than with isradipine (18.4%).(ABSTRACT TRUNCATED AT 250 WORDS)

Exercise and heart transplantation. A review

Results of heart transplantation as therapy for end-stage cardiac diseases are encouraging not only because of actuarial survival curves but also because of the recovered quality of life for the heart transplant recipient. Although heart transplantation drastically improves the physical capacity of the patients, heart recipients still have a reduced maximal aerobic capacity compared to healthy people. Altered resting and exercise haemodynamics, due to cardiac denervation, are a common finding after orthotopic heart transplantation: increases in heart rate and stroke volume at exercise are first linked with the augmented venous return and later with the increased plasmatic nor-adrenaline level. Maximal heart rate and stroke volume are both reduced when compared to innervated heart. Reduced cardiac output response to exercise therefore results in early anaerobic metabolism, acidosis, hyperventilation and diminished physical capacity. In spite of an altered ventilatory adaptation to exercise, characterised by hyperpnoea in most transplant patients, ventilation is not the limiting factor for exercise in heart recipients without associated obstructive pulmonary disease. Endurance training restores lean tissue, decreases submaximal minute ventilation, increases peak work output, maximal ventilation and peak heart rate. Guidelines for prescribing exercise are not yet standardised due to the limited number of studies on a sufficient cohort of heart recipients. Nevertheless, recommendations similar to those used for persons with coronary heart disease, with modifications due to the denervated heart, seem to be used. The cardiocirculatory and pulmonary capacity of heart transplant recipients allow them to undertake endurance sports activities such as walking, jogging, cycling and swimming, and these should be encouraged.

Efficacy of diclazuril against Eimeria dispersa in turkeys

Diclazuril, a new anticoccidial drug, was tested for its efficacy against Eimeria dispersa in turkeys. A dose-titration study indicated that diclazuril at dosages of 0.5, 1, and 2 ppm in the feed was highly effective in terms of weight gain and suppression of lesions, abnormal droppings, and oocyst shedding.

Effects of isradipine on peripheral hemodynamic reflex responses in mild-to-moderate essential hypertension

In a randomized double-blind, placebo-controlled, crossover study of isradipine (5 mg twice daily), effects on peripheral hemodynamic reflex responses were studied in nine patients (mean age 48 years) at baseline and after six weeks of active treatment. Assessments included vital signs, resting blood flow in the calf and finger (using an electrocardiograph-triggered venous occlusion plethysmograph), reflex responses during isometric exercise and cold pressor resistance, and venous capacitance in the forearm and calf. Isradipine lowered systolic and diastolic blood pressure as well as mean arterial pressure in patients with mild-to-moderate essential hypertension without reflex tachycardia or venoconstriction. All of the reflex responses studied were attenuated. It is concluded that vasodilatation of the peripheral circulation induced by isradipine contributes partially to the blood pressure-lowering effect.

Helminth and protozoan parasites in dogs and cats in Belgium

This study investigates the level of helminthic and protozoal infestation over the last 10 years in strays, well-cared-for dogs and cats. Determination of the prevalence of infections was based either on faecal examination or on worm counts at necropsy. Of 2324 faecal flotations (NaCl sp.gr. 1.20) of stray dogs, 34.2% had eggs or proglottids of one or more worm species consisting of Toxocara canis (17.4%), Toxascaris leonina (10.1%), Uncinaria stenocephala (11.4%), Trichuris vulpis (7.0%) and cestodes (2.1%). Isospora oocysts were observed in 5.2% of the dogs. The data on the distribution of the various worm species in the positive dogs indicate that T. canis eggs were by far the most common (50.9%). Necropsy data from 212 infected dogs indicate that 38.9% were infected with T. canis and 33.7% with T. leonina. The overall prevalence of worm infestation of 246 well-cared-for kennel dogs, based on worm egg counts by the McMaster technique, was 36.1%. Of 30 feline faecal samples examined by flotation, 83.3% were positive for parasites, including Toxocara cati (60%), Ancylostoma tubaeformae (36.6%), Taenia (Hydatigera) taeniaeformis (20%) and coccidia (30%). Toxocara cati was the most frequently found worm species at the necropsy of 25 cats (52%). Toxoplasma was not observed.

Anticoccidial efficacy of diclazuril in pheasants

Diclazuril, a new anticoccidial drug, was tested in young pheasants artificially infected with the three most common pathogenic species of Eimeria, E colchici, E duodenalis and E phasiani. In two replicate experiments each with 40 birds the mortalities in the infected controls were 50 and 25 per cent. Diclazuril was administered in the feed at dose levels of 1, 2 and 4 ppm from the day before the inoculation of coccidia until the end of the test on day 6 after infection. The 1 ppm dose failed to inhibit the development of the parasite completely, as was shown by a reduction of the weight gain of the birds and the output of a small number of oocysts. Diclazuril at 2 or 4 ppm adequately controlled the infection, with weight gains similar to those of the uninfected controls. At all dose levels, mortality, intestinal lesions and diarrhoea were prevented.

Diclazuril, a new broad-spectrum anticoccidial for chickens. 3. Floor-pen trials

Diclazuril is a benzeneacetonitrile showing great promise as a broad-spectrum anticoccidial agent for chickens, turkeys, and rabbits. The high anticoccidial activity of diclazuril in chickens, as first reported in dose-titration studies and battery trials, was confirmed in three floor-pen trials. The efficacy was demonstrated against six major pathogenic species of Eimeria after artificial infection with one or more species. The experimental data indicated that diclazuril, at dose levels of .5, .75, 1, and 2 ppm, had a high anticoccidial activity in terms of preventing mortality, suppressing or reducing lesion scores, and allowing for normal weight gains as well as productivity. The performances obtained with diclazuril was generally comparable with that of salinomycin at 60 ppm and that of lasalocid at 90 ppm.

Efficacy of diclazuril in the prevention and cure of intestinal and hepatic coccidiosis in rabbits

The efficacy of diclazuril against intestinal and hepatic coccidiosis was studied in artificially infected rabbits. Prophylaxis against intestinal coccidiosis was evaluated using a mixed infection of Eimeria intestinalis, Eimeria magna and Eimeria perforans. Continuous medication in the feed at 1 p.p.m. was 100% effective in reducing oocyst output and faecal scores, and weight gain and feed efficiency were normal. Hepatic coccidiosis induced by Eimeria stiedai was prevented at 0.5 and 1 p.p.m. as shown by negative oocyst counts, normal liver weight, absence of liver lesions, and normal body-weight gain and feed efficiency. Medication at 1 p.p.m. for 7 consecutive days during the prepatent phase of hepatic coccidiosis resulted in large reductions in oocyst counts and lesion scores with a normal liver weight and growth performance. Diclazuril at 1 p.p.m. in the feed prevented both intestinal and hepatic coccidiosis in rabbits and can be advocated for safe mass medication.

Efficacy of diclazuril against turkey coccidiosis in dose-titration studies

Diclazuril, a new anticoccidial drug, was tested for its efficacy in turkeys against single Eimeria infections. Dose-titration studies indicated that diclazuril at dosages of 0.1, 0.5, 1, and 2 ppm was highly effective against the major pathogenic species-E. adenoeides, E. gallopavonis, and E. meleagrimitis-in terms of weight gain and suppression of lesions, abnormal droppings, and oocyst shedding.

Efficacy of diclazuril against turkey coccidiosis in a floor-pen experiment

Diclazuril, a new anticoccidial drug, was tested for its efficacy in turkeys against mixed Eimeria infections. A floor-pen trial indicated that diclazuril at dosages of 0.5 ppm and 1 ppm in the feed was highly effective against the major pathogenic species E. adenoeides, E. gallopavonis, and E. meleagrimitis in suppressing intestinal and cecal lesions and oocyst shedding. Weight gain and feed conversion improved, particularly at 1 ppm.

Diclazuril, a new broad spectrum anticoccidial drug in chickens. 2. Battery trials

Battery trials have confirmed the broad spectrum anticoccidial activity of diclazuril as previously reported in dose titration studies. The advocated dose level of 1 ppm in the diet demonstrated excellent activity against the economically most important Eimeria species. At this dose level, body weight gains were comparable to those of uninfected, unmedicated controls and the oocyst production was negative in most species. Lesion scores and dropping scores were nil or highly reduced. An E. maxima-147 strain, less sensitive to ionophores, also responded well to diclazuril. It was concluded that diclazuril is a promising anticoccidial for the control of all species of coccidia that cause losses to the poultry industry.

Efficacy of flubendazole against gastrointestinal and lung nematodes in pigs

Three trials were carried out on landrace pigs of various ages to assess the anthelmintic efficacy of flubendazole. The pigs were either artificially infected with Metastrongylus apri or naturally or artificially infected with the gastrointestinal nematodes Ascaris suum, Oesophagostomum dentatum or Hyostrongylus rubidus. For mass medication of young pigs and fatteners a dose regimen of 30 ppm flubendazole in the feed for 10 consecutive days was 100 per cent effective against the four nematode species. For individual medication a single dose of 5 mg/kg bodyweight administered in a small amount of feed was also 100 per cent effective. No side effects were observed.

[Clazuril: a new anticoccidial agent for pigeons]

The effectiveness of clazuril (Appertex), a new anticoccidial agent for the treatment of pigeons is described in the present study. Clazuril, a benzene-acetonitrile derivative, is administered in a single dose. In laboratory studies, 121 carrier pigeons infected with E. labbeana and E. columbarum were treated once with clazuril in gelatin capsules at dose levels of 10 mg, 5 mg, 2.5 mg, 1.25 mg, 0.63 mg or with a placebo. When a single dose of 2.5 mg and higher was administered, all faecal samples became negative for oocysts within seven days after treatment. In the field studies, 1531 young and full-grown carrier pigeons, from 116 infected dove-cotes, were treated with 1 tablet of 2.5 mg clazuril. Seven days after treatment, the faecal samples of 105 dove-cotes were negative for oocysts of E. Labbeana and E. columbarum; in six dove-cotes, infection was also virtually reduced to zero. Performance in racing was not affected by treatment and side-effects were not observed.

Anthelmintic efficacy of flubendazole paste against nematodes and cestodes in dogs and cats

Small dogs and cats, naturally infected with nematodes and cestodes, were used in a critical test under laboratory conditions to determine the palatability and efficacy of flubendazole as a past formulation. Subsequently, a control test in dogs was conducted under field conditions. A 4.4% past formulation was given at a dosage of 22 mg/kg of body weight once a day for 2 or 3 consecutive days. In a critical test in dogs, the efficacy against Toxocara canis was 97.4% after a 2-day administration and 100% after 3 days. Toxascaris leonina seemed to be the most susceptible worm species, since either 2 or 3 treatments were 100% active. The efficacy against Uncinaria stenocephala was 97.5% after 2 treatments; the same dose level for 3 days improved the efficacy to 100%. The efficacy was 100% for the removal of Trichuris vulpis after a daily dosage for 2 days and 96.7% after 3 days. One of 2 dogs infected with Taenia pisiformis was cleared of the infection after a 2-day treatment, and 3 of 4 dogs were cleared after a 3-day regimen. All cats were cleared of Toxocara cati after 2 or 3 days of treatment. One of 2 cats infected with Hydatigera taeniaeformis was cleared of the infection after a 2-day treatment; a 3-day treatment in 7 cats was 100% effective. The results in the laboratory test in dogs were confirmed under field conditions by a control test, based on the reduction of eggs per gram of feces count after treatment. The paste formulation was well accepted by all dogs and cats without any side effects.

Bradycardia, ventricular pauses, syncope, and sports

16 athletic patients were examined because of syncope, Stokes-Adams attacks, or both. The life-threatening condition required pacemaker implantation in 7 patients. 8 of the 9 other subjects became symptom-free after stopping heavy physical training. 37 top-ranking athletes underwent 24 h Holter monitoring. Pauses longer than 2 s occurred in 19% and resulted from sinus arrest. The longest pause lasted 2.5 s. Second-degree atrioventricular block was noted in 13%.

Inhibitory effects of pirenzepine on muscarinic stimulation of rat pancreas

The binding properties and pharmacological effects of pirenzepine were compared to those of atropine in isolated pancreatic acini and pancreatic membranes of rats. In the first preparation, pirenzepine and atropine blocked [N-methyl-3H]scopolamine ([3H]NMS) binding, pirenzepine being 110 times less potent than atropine (KD for pirenzepine 0.38 microM and for atropine 3.5 microM). A similar difference in potency was observed with respect to carbamylcholine stimulation of amylase secretion (IC50 for pirenzepine 4.5 microM and for atropine 30 nM) and calcium efflux (IC50 for pirenzepine 2.8 microM and for atropine 4 nM). Correspondingly, in rat pancreatic membranes, the KD values for pirenzepine and atropine were 250 and 1.5 nM, respectively. These data are compatible with the hypothesis that the in vitro antimuscarinic effect of pirenzepine on the rat pancreas is linked to the occupancy of a single homogeneous class of receptors with a low affinity for the antagonist.

Treatment of Trichuris suis infections in pigs with flubendazole

A severe outbreak of Trichuris suis infection in piglets is described. Fifteen per cent of the animals died and the morbidity, characterised by weight loss and diarrhoea, was over 50 per cent. The severity of symptoms observed in naturally infected pigs was related to the number of whipworms. A chemotherapeutic trial was worked out with flubendazole mixed in food for naturally infected and artificially infected piglets. Flubendazole at 30 ppm for five consecutive days controlled the infection in the pigs. Immature T suis in artificially infected pigs were also controlled at the same dose administered for 10 consecutive days.