Health services use by children identified as heterozygous hemoglobinopathy mutation carriers via newborn screening

Background

Newborn screening (NBS) for sickle cell disease incidentally identifies heterozygous carriers of hemoglobinopathy mutations. In Ontario, Canada, these carrier results are not routinely disclosed, presenting an opportunity to investigate the potential health implications of carrier status. We aimed to compare rates of health services use among children identified as carriers of hemoglobinopathy mutations and those who received negative NBS results.

Methods

Eligible children underwent NBS in Ontario from October 2006 to March 2010 and were identified as carriers or as screen-negative controls, matched to carriers 5:1 based on neighbourhood and timing of birth. We used health care administrative data to determine frequencies of inpatient hospitalizations, emergency department (ED) visits, and physician encounters through March 2012, using multivariable negative binomial regression to compare rates of service use in the two cohorts. We analyzed data from 4987 carriers and 24,935 controls.

Results

Adjusted incidence rate ratios (95% CI) for service use in carriers versus controls among children < 1 year of age were: 1.11 (1.06–1.17) for ED visits; 0.97 (0.89–1.06) for inpatient hospitalization; and 1.02 (1.00–1.04) for physician encounters. Among children ≥1 year of age, adjusted rate ratios were: 1.03 (0.98–1.07) for ED visits; 1.14 (1.03–1.25) for inpatient hospitalization and 0.92 (0.90–0.94) for physician encounters.

Conclusions

While we identified statistically significant differences in health services use among carriers of hemoglobinopathy mutations relative to controls, effect sizes were small and directions of association inconsistent across age groups and health service types. Our findings are consistent with the assumption that carrier status is likely benign in early childhood.

The Israeli national policy for discontinuation of isolation of carbapenem-resistant Enterobacterales carriers by carbapenemase type: a retrospective cohort study

OBJECTIVES

The Israeli national policy for containing carbapenemase-producing Enterobacterales (CPE) includes a protocol allowing for discontinuation of carrier status following spontaneous decolonization. We examined the strategy's effectiveness based on carbapenemase type.

METHODS

We performed a retrospective cohort study comparing individuals colonized with KPC- or NDM-producing Enterobacterales who underwent the process of isolation discontinuation. The primary outcome was reversion of carrier status, i.e. re-identification of the same CPE species following isolation discontinuation. We used survival analysis to estimate overall hazard ratio and performed competing-risks analysis using a Fine-Gray subdistribution hazard model and cause-specific hazard ratios.

RESULTS

Between 1 January 2006 and 1 January 2019 we identified 1694 individuals who met inclusion criteria, including 1337 (78.9%) carriers of KPC-producing Enterobacterales, 305 (18.0%) carriers of NDM-producing Enterobacterales and 52 (3.1%) carriers of dual KPC-/NDM-producing Enterobacterales. A total of 134 individuals (7.9%) had reversion of carrier status: 9.1% (121/1337) and 4.3% (13/305) of individuals with KPC- and NDM-producing Enterobacterales, respectively. The subdistribution hazard ratio of status reversion was not increased among carriers of NDM producers compared with KPC producers (0.567, 95% CI 0.320-1.000], p 0.052). Cause-specific hazard ratios yielded similar results (0.522, 95% CI 0.291-0.937, p 0.029.

CONCLUSIONS

Carriage of NDM-producing Enterobacterales was not associated with higher rates of reversion to carrier status following spontaneous decolonization than was carriage of KPC-producing Enterobacterales.

The Carrier Status of Streptococcus pneumoniae in a Multi-National Medical Student Population

BACKGROUND

Nasopharyngeal carriage of Streptococcus pneumoniae (S. pneumoniae) is a well-established risk factor for invasive disease. An unnecessarily high incidence of morbidity attributed to S. pneumoniae is vaccine-preventable. The objectives of this study were to determine the prevalence of S. pneumoniae carriage and to analyze the different vaccination schemes in a multinational population of final-year medical students.

STUDY DESIGN

An observational cross-sectional study including final-year medical students attending their Infectious Diseases rotation.

METHODS

One nasal and pharyngeal swab were collected from each participant who underwent a minimum eight-hour period of fasting and without rinsing or brushing teeth. Written informed consent was obtained from all participants. A univariate statistical analysis was carried out with statistical significance set at p <0.05.

RESULTS

Fifty students agreed to participate in this study (age range: 23-35, average: 24.86 ± 2.12 years). Six (12%) students had the pneumococcal vaccine: four (16%) from the foreign group and two (8%) from the Romanian group (OR: 2.19, 95% CI: 0.36-13.21, p=0.39). The carrier status for S. pneumoniae was 0%. A total of 12 (24%) specimens yielded microbial presence: S. aureus (n=8), S. pyogenes (n=1), Group C Streptococcus (n=1), Group G Streptococcus (n=1) and K. pneumoniae (n=1). All 13 (26%) specimens of alpha-hemolysis were identified from foreign students (OR: 55.08, 95% CI: 3.02-1003.75, p=0.0068), but had no clinical relevance, S. pneumoniae being ruled out.

CONCLUSIONS

The carrier status among vaccinated participants was 0%. The rate of microorganism isolation was twice that in Romanian students compared to foreign students.

Salmonellosis in Hedgehogs

African pygmy hedgehogs are popular pets worldwide. The knowledge and understanding of pet hedgehog common veterinary conditions are increasing as new information and research are published; however, there is still much to learn about this fascinating animal. Salmonella is one of the most common zoonoses worldwide and is naturally isolated from the intestinal tract of many animal species, including hedgehogs. This article discusses the cause, clinical signs, diagnosis, treatment, and prevention of salmonella infection in hedgehogs, primarily focusing on African pygmy hedgehogs, with some reference to European hedgehogs.

Generalized glycogenosis in Brahman-derived breeds: diagnosis and prevalence in Argentina

Generalized glycogenosis is a lethal autosomal recessive disease caused by a deficient activity of the acidic 1,4-α-glucosidase enzyme and characterized by an accumulation of glycogen within lysosomes. Three mutations in the GAA gene causing bovine generalized glycogenosis have been identified in two cattle breeds, Brahman and Shorthorn. The objective of this study was to evaluate the prevalence of carriers of the E7 mutation in the GAA gene in Argentinean Brahman-derived herds. A total of 930 Braford, 94 Brangus, and 8 Brahman samples were analyzed. The genotyping was done by polymerase chain reaction and restriction fragment length polymorphism (PCR/RFLP). We found that 12.02% (95% CI 12.00-12.04) of the total number of samples received were heterozygous (i.e., carriers) for the E7 mutation, while 12.58% (95% CI 12.56-12.60) of the Braford, 6.38% (95% CI 6.26-6.51) of the Brangus, and 12.50% (95% CI 9.82-15.18) of the Brahman samples were carriers of this loss-of-function allele. Neither breed nor sex were significantly associated to the presence of the mutation. The prevalence informed in this study is similar to the average prevalence reported for Australian Brahmans. The finding of heterozygous animals suggests that breeders and insemination centers should continue screening their herds to minimize the dissemination of this deleterious allele.

Rare cause of Hemophagocytic Lymphohistiocytosis due to mutation in PRF1 and SH2D1A genes in two children - a case report with a review

Background

Hemophagocytic Lymphohistiocytosis (HLH) is a rare, complex, life-threatening hyper-inflammatory condition due to over activation of lymphocytes mediated secretory cytokines in the body. It occurs as a primary HLH due to genetic defect that mostly occurs in the childhood and associated with early neonatal death. Secondary HLH is triggered by secondary to infection and can occur at any age.

Case presentation

The current report presents two cases of HLH. Case 1, three-months-old boy born to second degree consanguineous parents was clinically suspected with HLH. A pathogenic variant in exon 2 of PRF1 gene [c.386G > C (p.Trp129Ser); FLH-type2] was detected. The parents and the fetus under investigation were shown to be heterozygous carriers, while Case-1 was homozygous for the said variant. Case 2, a one and half-year old male child referred for work-up was born to non-consanguineous young parents. His HLH suspicion was in accordance with HLH-2004 Revised diagnostic guidelines (fulfilling 5/8 criteria). Molecular study revealed hemizygous likely pathogenic variant c.138-3C > G in intron 1 of SH2D1A gene. Both the mother and younger sister were confirmed to be the carrier of the same variant.

Conclusion

This study has represented two rare cases of HLH carrying missense variant in PRF1 and splice site variant in SH2D1A gene. Detailed molecular analysis has helped the families with precise genetic counselling and prenatal diagnosis during subsequent pregnancy. It is advocated that male patients presenting with EBV-associated HLH may be screened for XLP that may lead to early diagnosis and therapeutic implication if any.

Electronic supplementary material

The online version of this article (10.1186/s12887-019-1444-4) contains supplementary material, which is available to authorized users.

Genetic Counselors' Experience with and Opinions on the Management of Newborn Screening Incidental Carrier Findings

Newborn screening (NBS) is a public health program whose aim is to identify infants who will be clinically affected with a serious metabolic, genetic, or endocrine disorder; however, the technology utilized by many NBS programs also detects infants who are heterozygous carriers for autosomal recessive conditions. Discussion surrounding disclosure of these incidental carrier findings remains controversial. The purpose of this study was to assess genetic counselors’ attitudes about disclosure of carrier status results generated by NBS and to gather data on their experiences with incidental carrier findings. An electronic survey was distributed to genetic counselors of all specialties via the NSGC listserv, and a total of 235 survey responses were analyzed. Quantitative data were analyzed using IBM SPSS v24, and qualitative data were manually analyzed for thematic analysis. Results show that the counselor participants were overall in favor of routine disclosure. Those with experience in NBS were much more likely to strongly agree with one or more reasons for disclosure (p < 0.001), whereas those with five or fewer years of experience were more likely to strongly agree with one or more reasons for non-disclosure (p = 0.031). Qualitative analysis identified key motivating factors for disclosure, including helping parents to understand a positive screen, parents may otherwise be unaware of reproductive risk and they may not otherwise have access to this information, and, while genetic testing is inherently a complex and ambiguous process, this does not justify non-disclosure. The main motivating factor for non-disclosure was the need for better counseling and informed consent. The data suggest that implementation of an “opt-in/out” policy for parents to decide whether or not to receive incidental findings would be beneficial. The results of this study support the continued disclosure of incidental carrier findings; however, additional research is necessary to further determine and implement the most effective disclosure practices.

Evidence of subclinical foot-and-mouth disease virus infection in young calves born from clinically recovered cow under natural condition

Foot-and-mouth disease (FMD) is a highly contagious and economically important, transboundary viral disease of cloven-hoofed animals. It is known that an asymptomatic, persistent FMD virus (FMDV) infection may occur subsequent to acute or subclinical FMDV infection in adult ruminants. However, virus persistence in young calves has not been studied. In the current investigation, FMDV infection parameters were examined for calves born to FMD-clinically recovered cows (CRC), asymptomatic cows from infected herds (ASC) and cows from with no history of FMD (NHF). The study was conducted in natural condition after FMD outbreaks in two dairy herds in India. No calves described herein had any clinical signs of FMD. Six out of 12 calves born to CRC had detectable FMDV RNA in oesophageal-pharyngeal fluid consistent with asymptomatic FMDV infection. Three of the 12 calves of CRC group had seroreactivity against FMDV non-structural proteins. One calf had detectable FMDV RNA at two consecutive samplings at 2 months apart. However, infectious FMDV was not isolated from any calf in the study. None of the calves in the ASC or NHF groups had any evidence of FMDV infection. Overall, these data are consistent with earlier report on calves having been infected in utero. Further investigation of FMDV persistence in calves under controlled conditions may lead to greater understanding of the viral pathogenesis.

Immune Response in Goats to Different Payloads of FMDV Monovalent Vaccine: Protection Against Virulent Challenge and Development of Carrier Status

The relationship of Foot-and-Mouth Disease virus antigen payload and number of dose of vaccine conferring protection against virus challenge in goats was studied. Goats vaccinated with oil adjuvant Foot-and-Mouth Disease vaccines containing different antigen payloads with or without booster resisted virulent challenge at 21 days post-vaccination or 7 days after booster respectively. However, localized sub-clinical infection was observed in two vaccinated goats on 35 days post-challenge. RNA could be detected from 31.8% of vaccinated goats (10(2.69)-10(4.99) viral RNA copies per cotton swab of nasal secretions) on day 35 post-challenge. Since no live virus could be isolated after 5 days post-challenge, the risk of these animals transmitting the disease was probably very low. The finding showed that oil adjuvant Foot-and-Mouth Disease vaccines containing antigen payload of 1.88 μg may prevent or reduce the local virus replication at the oropharynx and shedding of virus from nasal secretions and thereby reduce the amount of virus released into the environment subsequent to exposure to live virus. This study also showed that goats with poor sero conversion to vaccination can be infected without overt clinical signs and became carriers like sheep.