Novel Clinical Monitoring Approaches for Reemergence of Diphtheria Myocarditis, Vietnam

Alpha-1 antitrypsin inhibits Clostridium botulinum C2 toxin, Corynebacterium diphtheriae diphtheria toxin and B. anthracis fusion toxin

The bacterium Clostridium botulinum, well-known for producing botulinum neurotoxins, which cause the severe paralytic illness known as botulism, produces C2 toxin, a binary AB-toxin with ADP-ribosyltranferase activity. C2 toxin possesses two separate protein components, an enzymatically active A-component C2I and the binding and translocation B-component C2II. After proteolytic activation of C2II to C2IIa, the heptameric structure binds C2I and is taken up via receptor-mediated endocytosis into the target cells. Due to acidification of endosomes, the C2IIa/C2I complex undergoes conformational changes and consequently C2IIa forms a pore into the endosomal membrane and C2I can translocate into the cytoplasm, where it ADP-ribosylates G-actin, a key component of the cytoskeleton. This modification disrupts the actin cytoskeleton, resulting in the collapse of cytoskeleton and ultimately cell death. Here, we show that the serine-protease inhibitor α1-antitrypsin (α1AT) which we identified previously from a hemofiltrate library screen for PT from Bordetella pertussis is a multitoxin inhibitor. α1AT inhibits intoxication of cells with C2 toxin via inhibition of binding to cells and inhibition of enzyme activity of C2I. Moreover, diphtheria toxin and an anthrax fusion toxin are inhibited by α1AT. Since α1AT is commercially available as a drug for treatment of the α1AT deficiency, it could be repurposed for treatment of toxin-mediated diseases.

Diphtheria's Dual Threat: Amplifying Awareness of Cardiac Complications for Enhanced Intervention

Even though immunization can prevent illness, diphtheria, which is caused by toxic strains of Corynebacterium diphtheriae, remains a serious public health risk. Although the worldwide incidence has declined, it still poses a serious hazard in developing countries, such as Pakistan, where new data suggest an increase in cases. A significant proportion of patients with respiratory diphtheria experience cardiac complications, specifically myocarditis, which carries a high death risk of 50% to 75%. The diphtheria toxin's affinity for cardiac tissues is the cause of these consequences, which include arrhythmias and myocardial dysfunction. Recent studies from Lady Reading Hospital in Peshawar show the seriousness of the situation, with 73 patients presenting with cardiac complications in just one year, resulting in a devastating fatality rate despite early management. This highlights the pressing need for increased awareness and all-encompassing immunization campaigns, particularly for children who have received insufficient vaccinations. Timely vaccination and booster doses are critical for reducing myocarditis-related mortality, mandating prioritizing immunization efforts to defend susceptible populations globally.

Diphtheria-Associated Myocarditis: Clinical Profiles and Mortality Trends in a Tertiary Care Hospital in Pakistan

BACKGROUND

Corynebacterium diphtheriae infection, causing diphtheria, is a public health concern, particularly in developing nations like Pakistan. Despite immunization efforts, recent outbreaks since 2022 have emphasized the continuing threat. This study focuses on describing the clinical characteristics of children with diphtheria-induced myocarditis and exploring the association between early cardiac abnormalities, future fatality rates, and contributing factors.

METHODS

A one-year cross-sectional study was undertaken at Lady Reading Hospital MTI Peshawar, encompassing 73 pediatric patients diagnosed with diphtheria-associated myocarditis. Data, including demographic characteristics, cardiac enzymes, and serial ECG and echocardiography data, were gathered from the health management information system (HMIS). Institutional Ethical Committee approval was obtained, and informed consent was waived due to its retrospective nature.

RESULTS

Gender distribution within the study was balanced, with 35 males (47.9%) and 38 females (52.1%). ECG data revealed various prevalence rates: 27.4% for rhythm abnormalities, 20% for conduction abnormalities, 6.8% for ischemia alterations, and 20.5% for normal findings. Treatment measures included anti-diphtheria serum (ADS) in 87.7% and temporary pacemaker placement (TPM) in 13.7% of patients. Echo findings indicated a variety of cardiac dysfunctions: 53.4% with no dysfunction, 9.6% mild malfunction, 6.8% with moderate dysfunction, and 30.1% with severe dysfunction. The categorization of creatine kinase (CK), lactate dehydrogenase (LDH), and troponin I (Trop I) gave insights into the biochemical aspects.

CONCLUSION

This study gives a full insight into the clinical symptoms of diphtheria-induced myocarditis in children. The findings can help establish a foundation for ongoing study into potential gender-related trends in clinical outcomes, contributing to improved care and preventative methods.

Unmasking diphtheria in Nigeria: A multifaceted approach to tackle outbreaks and improve immunization rates among the Nigerian population-An updated correspondence

Background and aims

The World Health Organization has recently declared the frequent outbreaks of diphtheria in Nigeria as a public health concern. Although vaccination efforts have been successful in Nigeria, unfortunately, the recent 2023 outbreak in Nigeria has been nothing short of distressing. Of course, cases of diphtheria incidence are under-reported in Nigeria. This present article aims to proffer a possible multifaceted approach to tackle outbreaks of diphtheria in Nigeria and improve immunization rates against the disease among the Nigerian population.

Methods

In writing this study, literature search was done about diphtheria in Nigeria using the following keywords: "diphtheria, prevalence, vaccination, efforts, challenges, and Nigeria" on PubMed, Web of Science, Google Scholar, and ResearchGate within 10 years.

Result

This study found that an estimated seven million people remain unvaccinated and are at risk for infection in the country, especially people living in the Northern part of the country. Between the June 30 and August 31, 2023, Nigeria recorded an unusual increase in the number of confirmed cases of diphtheria, where a total of 5898 suspected cases were reported from 59 local government areas in 11 states across Nigeria. The majority (99.4%) of suspected cases of the disease were reported from six states: Kano (1816), Katsina (234), Yobe (158), Bauchi (79), Kaduna (45), and Borno (33).

Conclusion

If Nigeria is to emerge beyond these frequent epidemics of diphtheria, the Nigerian government must work on tackling this issue on multiple fronts simultaneously, that is, at the national and international levels, as we believe that these levels would give a holistic way to unmask diphtheria in Nigeria.

Immunopathogenesis and immunomodulatory therapy for myocarditis

Myocarditis is an inflammatory cardiac disease characterized by the destruction of myocardial cells, infiltration of interstitial inflammatory cells, and fibrosis, and is becoming a major public health concern. The aetiology of myocarditis continues to broaden as new pathogens and drugs emerge. The relationship between immune checkpoint inhibitors, severe acute respiratory syndrome coronavirus 2, vaccines against coronavirus disease-2019, and myocarditis has attracted increased attention. Immunopathological processes play an important role in the different phases of myocarditis, affecting disease occurrence, development, and prognosis. Excessive immune activation can induce severe myocardial injury and lead to fulminant myocarditis, whereas chronic inflammation can lead to cardiac remodelling and inflammatory dilated cardiomyopathy. The use of immunosuppressive treatments, particularly cytotoxic agents, for myocarditis, remains controversial. While reasonable and effective immunomodulatory therapy is the general trend. This review focuses on the current understanding of the aetiology and immunopathogenesis of myocarditis and offers new perspectives on immunomodulatory therapies.