Factors Associated with the Outcome of 2023 Diphtheria Outbreak in Jigawa State, Nigeria: A Retrospective Review of the Surveillance Data.

OBJECTIVE: The objective of this study was to identify the factors associated with the outcome of the 2023 diphtheria outbreak in Jigawa State, Nigeria. METHODS: A descriptive cross-sectional study was conducted amongst all line-listed diphtheria cases reported from Jigawa State, Nigeria, using the 2023 Integrated Disease and Surveillance Response line list of cases that met the World Health Organization case definition of diphtheria. A total of 245 line-listed cases from January 2023 to December 2023 met the criteria for inclusion in the study. Data were analysed using IBM SPSS version 22.0 with a P value set at ≤5%. Binary logistic regression was used to identify the independent predictors of the outcome of the 2023 outbreak. RESULTS: The maximum age of the line-listed cases was 39 years, and the minimum was 1 year with a median of 8 (interquartile range = 5-8) years. More than two-thirds (68.2%) of the cases were ≥5 years of age. More than one-third of the cases (39.6%) were from the northeast senatorial zone of the state. Out of the total 245 cases, 14 died of the disease representing a case fatality rate of 6%, and an attack rate of 3.4 per 100,000 populations. The majority of the cases (95.5%) had fever, cough (81.2%), pharyngitis (86.9%), tonsillitis (96.7%) and laryngitis (82.0%). More diphtheria-related mortalities were recorded amongst cases <5 years of age (7.7%), female cases (5.9%), rural residence (7.7%) and cases from the northeast senatorial zone (8.2%) of the state. Significantly higher mortalities (8.8%, P = 0.003) were recorded amongst cases with nasopharyngitis. The odds of diphtheria-related mortality were higher amongst cases who presented clinically with nasopharyngitis and were 4 times more likely to die (adjusted odds ratio = 3.9; 95% confidence interval = 1.1-14.3) compared with those with no nasopharyngitis. CONCLUSIONS: Significantly higher mortalities were recorded amongst diphtheria cases whose samples were not taken, and those with nasopharyngitis. These findings underscored the importance of improved immunisation uptake, early and prompt case detection, investigation and proper management.

The Burden and Risk Factors Associated with Infectious Diseases among Refugees in a Camp for Migrants in Porto Alegre: A Cross-Sectional Survey.

Refugees usually face a disproportionate burden of infectious diseases. Recently, Brazil has experienced an influx of refugees which demands the need for scaling up public health efforts to address the challenges. The research sought to study the burden and risk factors associated with infectious diseases among refugees received in the city of Porto Alegre. This was a cross-sectional study of 261 newly arrived refugees. The study sample was predominantly composed of Venezuelans (50.6%) and Haitians (44%), male (146: 56.7%), single (30.7%), with an average age of 33.38 (± 7.30) years. The average schooling was 10.42 (± 2.09) years. Diseases with the highest prevalence were influenza, whooping cough, diphtheria, and tuberculosis. There was significant association between the country of origin and presence of symptoms for infectious and contagious diseases, which warrants targeted interventions for reducing the incidence of these diseases among refugees in Brazil.

Seroprevalence of anti-diphtheria toxoid antibody and implications for vaccination policy in Vietnam's South-central coast: a cross-sectional study.

BACKGROUND: Diphtheria is a re-emerging infectious disease and public health concern worldwide and in Vietnam with increasing cases in recent years. This study aimed to assess the anti-diphtheria toxoid antibodies status in Khanh Hoa Province and identify factors contributing to the vaccination policy in the south-central coast of Vietnam. METHODS: This was a cross-sectional study to evaluate the seroprevalence of anti-diphtheria toxoid antibodies among 1,195 participants, aged 5 - 40 years in Khanh Hoa Province, Vietnam. Immunoglobulin G antibody levels against diphtheria were detected using a commercial anti-diphtheria toxoid enzyme-linked immunosorbent assay (SERION ELISA classic Diphtheria Immunoglobulin G) and were categorized following the World Health Organization guidelines. RESULTS: The mean anti-diphtheria toxoid antibody levels were 0.07 IU/ml (95% Confidence Interval: 0.07-0.08). Anti-diphtheria toxoid antibody levels were found to be associated with age and history of diphtheria vaccination. The 5-15 years age group had the highest levels (0.09 IU/ml), while the older age group had the lowest antibody level (p < 0.001). Individuals who received three doses (adjusted Odds ratio: 2.34, 95%CI: 1.35 - 4.07) or 4+ doses (adjusted Odds ratio: 2.45, 95%CI: 1.29 - 4.64) had a higher antibody level compared to those who received only one dose regardless of age. CONCLUSION: It is crucial to promote routine vaccination coverage to over 95% for children under one year of age with three primary doses of the diphtheria-containing vaccine, including additional doses at 18 months and 7 years of age. Booster doses should be promoted and administered to adolescents and adults every 10 years.

Respiratory diphtheria in the time of Omicron.

Abstract: Diphtheria is a potentially fatal bacterial infection caused by toxin-producing strains of corynebacteria, most often Corynebacterium diphtheriae and less commonly Corynebacterium ulcerans. Incidence of the disease has fallen significantly since the introduction of vaccination programs; it is now rare in countries with high vaccination coverage such as Australia. This article presents the most recent respiratory cases of diphtheria in two children in New South Wales-the first locally acquired childhood cases in Australia in 30 years-and discusses potential contributing factors. These encompass the lack of clinical awareness and the delays in laboratory diagnosis in regional laboratories. The cases also highlight the problem of vaccine hesitancy and the role that primary carers play in addressing these anxieties. While clinical management of the cases progressed well, factors in the public health responses were complicated by access to appropriate care and by delays in antibiotic sensitivity profiles. The public health response to these cases raises important considerations for clinicians and public health practitioners, including preparedness for rare and re-emerging diseases, the need for culturally safe environments and the importance of addressing vaccine hesitancy. Preparedness requires consideration of the capacity of regional health systems with fewer resources and of how public health departments can support response to multiple crises. Preparedness also relies on access to necessary diagnostic laboratory resources, on up-to-date guidelines, and on maintaining awareness among clinicians for these rare infections.

Retrospective Study of Infections with Corynebacterium diphtheriae Species Complex, French Guiana, 2016-2021.

Human infections with Corynebacterium diphtheriae species complex (CdSC) bacteria were rare in French Guiana until 2016, when the number of cases diagnosed increased. We conducted an epidemiologic, multicenter, retrospective study of all human CdSC infections diagnosed in French Guiana during January 1, 2016-December 31, 2021. A total of 64 infectious episodes were observed in 60 patients; 61 infections were caused by C. diphtheriae and 3 by C. ulcerans. Estimated incidence increased from 0.7 cases/100,000 population in 2016 to 7.7 cases/100,000 population in 2021. The mean patient age was 30.4 (+23.7) years, and male-to-female ratio was 1.7:1 (38/22). Of the 61 C. diphtheriae isolates, 5 tested positive for the diphtheria toxin gene, and all results were negative by Elek test; 95% (61/64) of cases were cutaneous, including the C. ulcerans cases. The increase in reported human infections underscores the need to raise awareness among frontline healthcare practitioners to improve prevention.

Diphtheria in a Swiss Asylum Seeker Reception Centre: Outbreak Investigation and Evaluation of Testing and Vaccination Strategies.

Objectives: To describe a suspected diphtheria outbreak in a Swiss asylum seeker reception centre, and to analyse its management response regarding testing and vaccination. Methods: We retrospectively analysed clinical, microbiology, and case management data of all asylum seekers tested for C. diphtheriae between 28th August and 31st December 2022 while residing at the centre. Results are reported descriptively. Results: Among 265 individuals tested, ten cases of cutaneous diphtheria, one simultaneous respiratory and cutaneous case, and nine respiratory carriers were identified. Mass throat screening, targeted throat testing and targeted wound testing yielded 4.8%, 4.3%, and 17.4% positive results, respectively. No respiratory carrier was identified among cutaneous cases undergoing a throat swab, and no symptomatic case was identified among individuals with unspecific throat symptoms. Rates of vaccination implementation of newly arriving asylum seekers before and after the outbreak were low (17.5% and 15.5%, respectively), as were rates of targeted vaccination among cases and close contacts. Conclusion: We provide evidence for transmission both prior to arrival and within the setting, suboptimal practices and timeliness of testing, and implementation gaps in vaccination.

Cluster of Nontoxigenic Corynebacterium diphtheriae Infective Endocarditis and Rising Background C. diphtheriae Cases-Seattle, Washington, 2020-2023.

BACKGROUND: Nontoxigenic Corynebacterium diphtheriae, often associated with wounds, can rarely cause infective endocarditis (IE). Five patients with C. diphtheriae IE were identified within 12 months at a Seattle-based hospital system. We reviewed prior C. diphtheriae-positive cultures to determine if detections had increased over time and evaluated epidemiologic trends. METHODS: We conducted a formal electronic health record search to identify all patients aged ≥18 years with C. diphtheriae detected in a clinical specimen (ie, wound, blood, sputum) between 1 September 2020 and 1 April 2023. We collected patient demographics, housing status, comorbidities, substance-use history, and level of medical care required at detection. We extracted laboratory data on susceptibilities of C. diphtheriae isolates and on other pathogens detected at the time of C. diphtheriae identification. RESULTS: Between 1 September 2020 and 1 April 2023, 44 patients (median age, 44 years) had a C. diphtheriae-positive clinical culture, with most detections occurring after March 2022. Patients were predominantly male (75%), White (66%), unstably housed (77%), and had a lifetime history of injecting drugs (75%). Most C. diphtheriae-positive cultures were polymicrobial, including wound cultures from 36 (82%) patients and blood cultures from 6 (14%) patients, not mutually exclusive. Thirty-four patients (77%), including all 5 patients with C. diphtheriae IE, required hospital admission for C. diphtheriae or a related condition. Of the 5 patients with IE, 3 died of IE and 1 from COVID-19. CONCLUSIONS: Findings suggest a high-morbidity outbreak disproportionately affecting patients who use substances and are unstably housed.

Pastern dermatitis outbreak associated with toxigenic and non-toxigenic Corynebacterium diphtheriae and non-toxigenic Corynebacterium ulcerans at a horse stable in Finland, 2021.

AIMS: Corynebacterium diphtheriae and Corynebacterium ulcerans, when producing toxin, are the cause of diphtheria, a potentially life-threatening illness in humans. Horses (Equus ferus caballus) are known to be susceptible to infection that may manifest clinically on rare occasions. In late 2021 and early 2022, specimens from five horses suffering from pastern dermatitis were cultured at the Laboratory of Clinical Microbiology at the Faculty of Veterinary Medicine, University of Helsinki, Finland. C. diphtheriae and/or C. ulcerans were recovered from all of these. This study aimed to (1) analyse the bacterial isolates and (2) describe the outbreak and identify possible sources of the infection and infection routes in the stable. METHODS AND RESULTS: Susceptibility testing, PCR for the tox gene, and Elek test for toxin production in PCR-positive isolates were performed. Whole genome sequencing was also conducted to achieve high-resolution strain typing. An epidemiological survey was done by means of a semi-structured interview of horses' caretaker, and contact tracing was done among people at the stable. Two tox gene-positive, toxin-producing C. diphtheriae belonged to sequence type (ST) 822. Other C. diphtheriae (n = 2, ST828) and C. ulcerans (n = 2, ST325 and ST838) isolates did not carry the tox gene. The epidemiological investigation explored numerous possible routes of transmission, but the definite source of infection was not identified. All established human contacts tested negative for diphtheriae. All horses recovered after antimicrobial treatment. CONCLUSIONS: Our study shows that C. diphtheriae and C. ulcerans may readily spread among horses at the same stable and complicate pastern dermatitis infections. These potentially zoonotic bacteria can cause outbreaks even in a country with a very low prevalence. Caretakers should be encouraged to wear gloves and practice good hand hygiene when treating infected skin lesions in horses.

Outbreak of Corynebacterium diphtheriae among asylum seekers in Belgium in 2022: operational challenges and lessons learnt.

Since 2022, European countries have been facing an outbreak of mainly cutaneous diphtheria caused by toxigenic Corynebacterium diphtheriae among asylum seekers. In Belgium, between 1 March and 31 December 2022, 25 cases of toxigenic C. diphtheriae infection were confirmed among asylum seekers, mostly among young males from Afghanistan. Multi-locus sequence typing showed that most isolates belonged to sequence types 574 or 377, similar to the majority of cases in other European countries. The investigation and management of the outbreak, with many asylum seekers without shelter, required adjustments to case finding, contact tracing and treatment procedures. A test-and-treat centre was organised by non-governmental organisations, the duration of the antimicrobial treatment was shortened to increase compliance, and isolation and contact tracing of cases was not possible. A vaccination centre was opened, and mobile vaccination campaigns were organised to vaccinate a maximum of asylum seekers. No more cases were detected between end December 2022 and May 2023. Unfortunately, though, three cases of respiratory diphtheria, including one death, were reported at the end of June 2023. To prevent future outbreaks, specific attention and sufficient resources should be allocated to this vulnerable population, in Belgium and at international level.

Multidrug-resistant Corynebacterium diphtheriae in people with travel history from West Africa to France, March to September 2023.

We describe 10 unlinked cases of Corynebacterium diphtheriae infection (nine cutaneous, one respiratory) in France in 2023 in persons travelling from Guinea, Mali, Senegal, Niger or Nigeria and Central African Republic. Four isolates were toxigenic. Seven genomically unrelated isolates were multidrug-resistant, including a toxigenic respiratory isolate with high-level resistance to macrolides and beta-lactams. The high rates of resistance, including against first-line agents, call for further microbiological investigations to guide clinical management and public health response in ongoing West African outbreaks.

Recurrent diphtheria outbreaks in Nigeria: A review of the underlying factors and remedies.

INTRODUCTION: The introduction of the diphtheria-tetanus-pertussis (DTP) vaccine into childhood immunization programs resulted in its widespread elimination in high-income countries. However, Nigeria is currently experiencing an outbreak. The primary cause of diphtheria outbreaks and its high mortality rates in Nigeria was waning herd immunity due to low DTP coverage and a lack of diphtheria antitoxin (DAT), respectively. However, the underlying causes of Nigeria's low DTP coverage and DAT supply remain unknown. METHOD: Relevant studies and reports included in our review were obtained by a search through Google Scholar, PubMed, and organization websites using the terms "Diphtheria-Pertussis-Tetanus vaccine OR Diphtheria antitoxin and Nigeria OR Diphtheria Outbreak." All articles considering diphtheria outbreaks, DTP vaccine, and DAT supply in Nigeria were considered without time restriction due to the paucity of data. We used the narrative synthesis approach to critically appraise, analyze, and draw inferences from the selected articles. RESULTS: The main causes of low DTP coverage are insufficient supply, an inefficient cold chain system, and low uptake due to poor health literacy and negative sociocultural and religious beliefs, whereas the key barriers to DAT availability are insufficient production by pharmaceutical industries because of low demand and priority. CONCLUSION: The underlying causes of Nigeria's low DTP coverage and DAT supply are multifactorial. Both short-term and long-term measures are needed to control this outbreak and prevent future occurrences.

A looming epidemic: combating the recurrent outbreaks of diphtheria in Nigeria.

Nigeria has endured several diphtheria outbreaks over the last few decades, mirroring a suboptimal population immunity across several demographics within the country. The country's northern region has been affected mainly by this infectious disease; it directly depicts the effect of poor DPT vaccine uptake amongst children in this region compared to other geopolitical zones in Nigeria. Whilst pharmaceutical intervention and surveillance activities have commenced as directed by the NCDC, to combat this public health menace, top leaders of the Nigerian healthcare system - public and private sectors, must understudy the predisposing factors gearing the recurrence of diphtheria in Nigeria and provide robust, research-based and scientific mechanisms to arrest the root causes of the incessant outbreaks. This article discusses the factors promoting the recurrent diphtheria outbreaks in Nigeria, the preexisting interventions with their existential deterrents, and new strategies recommended to curb the further resurgence of the disease.

Several confirmed and probable zoonotic cases of toxigenic Corynebacterium ulcerans, Queensland, Australia.

Background: Toxigenic Corynebacterium ulcerans is an emerging zoonosis globally, causing both cutaneous and respiratory diphtheria-like illness. In Queensland, human infection with toxigenic C. ulcerans is rare, with only three cases reported before October 2015. This case series describes five subsequent cases of toxigenic C. ulcerans in Queensland with links to companion animals. Methods: All data were collected as part of routine public health response, and strains were whole genome sequenced for further characterisation. Household contacts were screened, treated with appropriate antibiotics, and received a diphtheria toxoid-containing vaccine if more than five years had elapsed since their last dose. Findings: No epidemiological or genomic links could be established between any of the five patients, including between the two cases notified from the same locality within eight days of each other. The C. ulcerans strains from Cases Two, Four and Five were closely related to the strains isolated from their respective pets by whole genome sequencing. Domestic dogs were identified as the most likely mode of transmission for Cases One and Three; however, this was unable to be laboratory confirmed, since Case One's dog was treated with antibiotics before it could be tested, and Case Three's dog was euthanised and cremated prior to case notification. Interpretation: These are the first reported Australian cases of this emerging zoonosis with links to companion animals. These cases demonstrate the likely transmission route between companion animals and humans, with no evidence of human-to-human transmission. The existing requirement in the Queensland Health Public Health Management Guidelines, of restrictions on cases and some contacts while awaiting swab results, is currently under review.