Pediatric Leprosy Profile in the Postelimination Era: A Study from Surabaya, Indonesia

Children who live in leprosy-endemic areas are susceptible to infection due to early and frequent exposure to Mycobacterium leprae. Indonesia is on the verge of eliminating this disease (prevalence rate < 1/10,000 population), but pediatric leprosy continues to occur in low-endemic areas. This study aimed to evaluate pediatric leprosy over a decade in a tertiary hospital in Surabaya, Indonesia. A retrospective study of leprosy in children under 15 years old between 2010 and 2019 was conducted in the Morbus Hansen Division, Outpatient Clinic at Dr. Soetomo Hospital in Surabaya, Indonesia. Seventy pediatric leprosy cases were identified between 2010 and 2019, consisting of 58 multibacillary (MB)-type cases and 12 paucibacillary (PB)-type cases. Slit skin smear (SSS) was positive in 26 cases. There were two cases of grade-2 disability and 15 cases of leprosy reaction (erythema nodosum leprosum) in children at the time of diagnosis. There was an insignificant decline in the number of pediatric leprosy cases in the last 10 years. Cases and disabilities in children were found in some leprosy pocket areas even though the national elimination rate has been achieved. MB infections, disability, and treatment defaults were common problems in pediatric leprosy.

Trade-Offs Between Hepatic Host Defense and Metabolic Programs Underlie Sex-Biased Diseases

Current concepts in evolutionary medicine propose that trade-offs and mismatches with a shifting environment increase disease risk. While biological sex also impacts disease prevalence, contributions of environmental pressures to sex-biased diseases remain unexplored. Here, we show that sex-dependent hepatic programs confer a robust (~300%) survival advantage for male mice during lethal bacterial infection. The transcription factor BCL6, which masculinizes hepatic gene expression at puberty, is essential for this advantage. However, protection by BCL6 comes at a cost following dietary excess, resulting in overt fatty liver and glucose intolerance in males. Deleting hepatic BCL6 reverses these phenotypes but markedly lowers male fitness during infection, thus establishing a sex-dependent tradeoff between host defense and metabolic systems. We suggest that these tradeoffs, coupled with current environmental pressures, drive metabolic disease in males.

Bayesian updating and sequential testing: overcoming inferential limitations of screening tests

Background Bayes’ theorem confers inherent limitations on the accuracy of screening tests as a function of disease prevalence. Herein, we establish a mathematical model to determine whether sequential testing with a single test overcomes the aforementioned Bayesian limitations and thus improves the reliability of screening tests. Methods We use Bayes’ theorem to derive the positive predictive value equation, and apply the Bayesian updating method to obtain the equation for the positive predictive value (PPV) following repeated testing. We likewise derive the equation which determines the number of iterations of a positive test needed to obtain a desired positive predictive value, represented graphically by the tablecloth function. Results For a given PPV ($$\rho$$ ρ ) approaching k, the number of positive test iterations needed given a prevalence of disease ($$\phi$$ ϕ ) is: $$n_i =\lim _{\rho \rightarrow k}\left\lceil \frac{ln\left[ \frac{\rho (\phi -1)}{\phi (\rho -1)}\right] }{ln\left[ \frac{a}{1-b}\right] }\right\rceil \qquad \qquad (1)$$ n i = lim ρ → k l n ρ ( ϕ - 1 ) ϕ ( ρ - 1 ) l n a 1 - b ( 1 ) where $$n_i$$ n i = number of testing iterations necessary to achieve $$\rho$$ ρ , the desired positive predictive value, ln = the natural logarithm, a = sensitivity, b = specificity, $$\phi$$ ϕ = disease prevalence/pre-test probability and k = constant. Conclusions Based on the aforementioned derivation, we provide reference tables for the number of test iterations needed to obtain a $$\rho (\phi )$$ ρ ( ϕ ) of 50, 75, 95 and 99% as a function of various levels of sensitivity, specificity and disease prevalence/pre-test probability. Clinical validation of these concepts needs to be obtained prior to its widespread application.

Transient prophylaxis and multiple epidemic waves

<abstract><p>Public opinion and opinion dynamics can have a strong effect on the transmission rate of an infectious disease for which there is no vaccine. The coupling of disease and opinion dynamics however, creates a dynamical system that is complex and poorly understood. We present a simple model in which susceptible groups adopt or give up prophylactic behaviour in accordance with the influence related to pro- and con-prophylactic communication. This influence varies with disease prevalence. We observe how the speed of the opinion dynamics affects the total size and peak size of the epidemic. We find that more reactive populations will experience a lower peak epidemic size, but possibly a larger final size and more epidemic waves, and that an increase in polarization results in a larger epidemic.</p></abstract>

Variation in the Accuracy of Endpoint Selection in Clinical Studies for Rare Diseases in Respect of Increasing Knowledge on Disease-Severity Measurement

Background: Previous research assessed the accuracy of disease-severity measurement in clinical studies as a mathematical relationship between the set of endpoints selected and the disease-severity scale (DSS), a surrogate for the theoretical Neutral list of indicators representing the disease phenotype. New DSSs are continually developed, so clinical studies’ operationalisation of the Neutral list and resulting relative neutrality may vary over time. We assessed variation in the neutrality of clinical studies over time and the probability of false positive and false negative classifications at different disease prevalence rates.Methods: We used search strings extracted from the Orphanet Register of Rare Diseases using a proprietary algorithm to conduct a systematic review of studies published until January 2021 per Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines. Overall, 483 studies and 12 rare diseases met inclusion criteria. We extracted all indicators from clinical studies and calculated neutrality and its components, sensitivity and specificity, as well as the probability of misclassifications at 20%, 50% and 80% disease prevalence rates at two time points, the times of publication of the first and last DSS. Surrogate Neutral lists were the first DSS and a composite of all later DSSs.Results: Over time, the neutrality of clinical studies increased for six diseases and decreased for five diseases, driven by sensitivity for all but Friedreich ataxia. The neutrality of clinical studies in encephalitis decreased, but sensitivity remained constant at zero. At both timepoints, the likely false negative rate increased and the likely false positive rate decreased with increasing disease prevalence. The probability that the least neutral clinical study for most diseases would yield a false positive result was equal to one at all disease prevalence rates. Conclusions: The potential for accurate clinical trial disease-severity measurement increases over time. Neutral theory showed that endpoint selection and DSSs may need improvement in Charcot Marie Tooth disease, Gaucher disease Type I, Huntington’s disease, Sjogren’s syndrome and Tourette syndrome. Using Neutral theory to benchmark disease-severity measurement in rare disease clinical trials may reduce the risk of misclassification, ensuring that recruitment and treatment effect assessment optimise medicine adoption and benefit patients.

Prevalence and spatial distribution characteristics of human echinococcosis in China

Background Echinococcosis is a zoonotic parasitic disease caused by larval stages of cestodes belonging to the genus Echinococcus. The infection affects people’s health and safety as well as agropastoral sector. In China, human echinococcosis is a major public health burden, especially in western China. Echinococcosis affects people health as well as agricultural and pastoral economy. Therefore, it is important to understand the prevalence status and spatial distribution of human echinococcosis in order to advance our knowledge of basic information for prevention and control measures reinforcement. Methods Report data on echinococcosis were collected in 370 counties in China in 2018 and were used to assess prevalence and spatial distribution. SPSS 21.0 was used to obtain the prevalence rate for CE and AE. For statistical analyses and mapping, all data were processed using SPSS 21.0 and ArcGIS 10.4, respectively. Chi-square test and Exact probability method were used to assess spatial autocorrelation and spatial clustering. Results A total of 47,278 cases of echinococcosis were recorded in 2018 in 370 endemic counties in China. The prevalence rate of human echinococcosis was 10.57 per 10,000. Analysis of the disease prevalence showed obvious spatial positive autocorrelation in globle spatial autocorrelation with two aggregation modes in local spatial autocorrelation, namely high-high and low-high aggregation areas. The high-high gathering areas were mainly concentrated in northern Tibet, western Qinghai, and Ganzi in the Tibetan Autonomous Region and in Sichuan. The low-high clusters were concentrated in Gamba, Kangma and Yadong counties of Tibet. In addition, spatial scanning analysis revealed two spatial clusters. One type of spatial clusters included 71 counties in Tibet Autonomous Region, 22 counties in Qinghai, 11 counties in Sichuan, three counties in Xinjiang Uygur Autonomous Region, two counties in Yunnan, and one county in Gansu. In the second category, six types of spatial clusters were observed in the counties of Xinjiang Uygur Autonomous Region, and the Qinghai, Gansu, and Sichuan Provinces. Conclusion This study showed a serious prevalence of human echinococcosis with obvious spatial aggregation of the disease prevalence in China. The Qinghai-Tibet Plateau is the "hot spot" area of human echinococcosis in China. Findings from this study indicate that there is an urgent need of joint strategies to strengthen efforts for the prevention and control of echinococcosis in China, especially in the Qinghai-Tibet Plateau.