Why is diphtheria reemerging

Bayesian analysis of population structure analysis exhibited multiple groups across the global collection indicating the degree of variation in C. The diphtheria vaccine strain C. However, the inevitable selection pressure on DT due to constant global increase in vaccination rates for diphtheria was evidenced by the recent increase in non vaccine type tox variants and NTTB strains. Prevalence of toxin diversity in C. Based on the evaluated AMR portfolio, it also became evident that the resistance genotypes are not restricted to a single country.

While majority of the C. Future studies should focus on asymptomatic carriage in vaccinated, partially vaccinated and unvaccinated individuals, especially covering communities that are at-risk communities or are known epidemiological hot spots of the disease.

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It is also a place to learn more about the activities of Nature Microbiology's editors and the policies and practices of the journal. A community from Nature Microbiology. Contributor Nature Comms. Behind the paper. Contributing authors. Corynebacterium diphtheriae. Philadelphia: Elsevier; — Clark KEN. Review of Epidemiology of Diphtheria Accessed on 10 July World Health Organization: Immunization, Vaccines and biological.

Vaccine preventable diseases vaccine monitoring systems Global Summary References Time Series: diphteria.

Re-emergence of diphtheria and pertussis: Implications for Nigeria. World Health Organization. The immunological basis for immunization series: module 2: diphtheria— update Geneva, Switzerland: World Health Organization; Accessed on 19 December Paediatric Association of Nigeria recommended routine immunization schedule for Nigerian children.

Niger J Paediatric. User Username Password Remember me. The first patient presented congestive cardiopathy and developed a rapidly fatal progressive illness. The second one recovered well from resection of the tissue compromised by the tumor regaining his baseline state of health Mattos-Guaraldi et al. Children with malignancies who are receiving chemotherapy should not be denied immunization with active vaccines Orgel et al.

Laboratories should be alert to the possibility of the isolation of C. Characterization of bacteriological aspects of endemic and epidemic strains and determination of genetic relatedness of C. The massive importation of epidemic strains into a susceptible population combined with social factors certainly facilitated the spread of the epidemic throughout European countries.

However, the source of the epidemic strains remains unclear Popovic et al. The emergence of the epidemic clone of toxigenic C. Emergence of related nontoxigenic C. In Switzerland, isolates came from skin infections of drug users, homeless persons, prisoners and elderly orthopedic patients.

Tetracycline resistance was typical for the isolates from Swiss injecting drug users Funke et al. Since 's, C. The wide dissemination of the sucrose-fermenting biotype, uncommonly found in most industrialized countries became a subject of concern. Biological and molecular characterization of Brazilian C. However, the prevalence of the sucrose fermenting biotype in our community remains not understood.

Little is known about initialization, buildup and spread of diphtheria epidemic. There are many unanswered questions with respect to the shift in the biotypes of C. Additional studies about vaccine components that may contribute to protection and mechanisms of virulence of diphtheria bacilli other than toxin production are needed. The worst epidemic of diphtheria in post vaccination era has drawn attention to the incomplete understanding of the epidemiology of diphtheria and virulence factors of C.

However, microbial factors that distinguish epidemic from endemic strains have not been identified. The fact that specific epidemic clones are responsible for severe outbreaks of diphtheria with thousands of deaths in industrialized countries make the argument that C. The occurrence of diphtheria among immunized persons, the increasing frequency of cases of endocarditis caused by non-toxigenic invasive clones associated to the prevalence of an atypical biotype of C.

Recent results also imply regulation of adherence and slime production as part of a global response to iron-limited environmental conditions that includes derepression of genes for the synthesis of cytotoxin and siderophores and for transport of the Fe III -siderophore complexes Moreira et al.

The adhesive activity is important for colonization and pathogenicity of bacterial species. Some of the main primary approaches and new developments in the study of the molecular basis of the adhesive process of C.

Recently, bacterial surface proteins of 67 and 72 kDa, named p, were isolated and related to attachment of C. Non-fimbrial p may play a key role in bacterial attachment to different host cells, facilitating the early step in C. Although diphtheria bacilli are generally considered an extracellular coloniser Funasa , recent investigations showed the ability of C.

Thus, entry into epithelial cells may provide a protected niche for toxigenic diphtheria bacilli survival, which may help to explain the ability of C. Additionally, invasion may be also relevant in vivo, allowing C. Initial control epidemic measures adopted improving routine childhood coverage rates and immunizing adults in "high-risk"occupational groups was unsuccessful.

The traditional approach used to control diphtheria, and the delays in implementing more intensive measures were followed by rapid spread of the epidemic Vitek et al. Efforts focused on immunizing adults at work sites, followed by non-working adults. The plan for coordinated action to control epidemic diphtheria in the countries of the former USSR, elaborated in by WHO in close collaboration with other governments and international agencies, was based on initiate mass immunization as rapidly as possible of all age group in the population; provide early detection and proper management of diphtheria cases; provide early identification and proper management of close contacts of diphtheria cases Dittmann et al.

In many advanced cases of the disease, the clinical diagnosis would normally precede microbiologic diagnosis. However, it is sometimes often difficult to diagnose diphtheria clinically, particularly in those countries where the disease is rarely seen. Accurate microbiologic diagnosis is crucial and is always regarded as being complementary to clinical diagnosis.

Laboratories must be alert to possible serious epidemiological situations. In Brazil, the current reporting of localized outbreaks attracted justifiable attention and the lack of expertise and materials to reliably identify toxigenic C.

Recently, as a result of the recent upsurge in disease activity, the WHO recently published a manual with current recommendations for isolation and identification of toxigenic C.

The rarity of cases and the expense and complexity associated with laboratory diagnosis provided many countries with the indication to cease screening throat specimens for C. Since diphtheria remain endemic in Brazil, expertise and recognition of the organism should not decline. Laboratory errors may be significant in view of the several clinical forms which disease can take in addition to the frequency of cases due to non-toxigenic C.

The fermentation of sucrose generally used to exclude diphtheria bacilli may lead to errors, particularly in regions of the world where isolation of atypical C. Given the immense public health significance attached to the isolation of C.

Classical tests commonly used to demonstrate the toxigenicity of a C. A rapid immunochromatographic ICS method for detection of diphtheria toxin has recently been developed Engler et al.

In contrast, the results of Brazilian endemic and epidemic C. The use of polymerase chain reaction PCR for rapid screening of toxigenic C. However, data are not yet sufficient for PCR to be accepted as a criterion for laboratory confirmation. PCR may be used with caution because some isolates of C. Immunization protects against toxigenicity but not against invasiveness of the organism. Thus, toxigenicity testing is only an indicator of the current status of the microbe and may provide a false sense of security.

Despite overall progress, devastating epidemics in human history occurred in XX century. These episodes illustrate the unpredictability of infectious disease emergence and death rates CDC The reemergence of diphtheria in European countries warns for a potential for epidemics of vaccine-preventable diseases elsewhere.

Circulation of toxigenic strains continues to present a threat to industrialized and developing countries and require achieving and maintaining high coverage with diphtheria toxoid-containing vaccines in both children and adults.

The worst diphtheria epidemic of the last decades forced a new generation of clinicians, laboratories, and epidemiologists worldwide to relearn old lessons and develop new methods in the prevention, control, and treatment of diphtheria.

In countries were diphtheria incidence is still relatively high and coverage is still inadequate laboratory support should be supplied due to ongoing severe limitations on basic laboratory capacity. Continued investment in improved vaccines, control strategies, training and laboratory techniques remain necessary.

Abrir menu Brasil. Abrir menu. Buzzi S, Sala G Immunity to diphtheria in advanced cancer patients. Ateneo Parmense Acta Biomed 51 : Kasmera 4 : Control of infectious disease.

Historical article. Mor Mortal Wkly Rep 48 : Corynebacterium diphtheriae surface proteins as adhesins to human erythrocytes. Molecular epidemiology of Corynebacterium diphtheriae from Northwestern Russia and surrounding countries studied by using ribotyping and pulsed-field gel electrophoresis.

J Clin Microbiol Successful control of epidemic diphtheria in the states of the former Union of Soviet Socialist Republics: lessons learned.