Streptococcal superantigens and the return of scarlet fever.

Streptococcus pyogenes (group A Streptococcus) is a globally disseminated and human-adapted bacterial pathogen that causes a wide range of infections, including scarlet fever. Scarlet fever is a toxin-mediated disease characterized by the formation of an erythematous, sandpaper-like rash that typically occurs in children aged 5 to 15. This infectious disease is caused by toxins called superantigens, a family of highly potent immunomodulators. Although scarlet fever had largely declined in both prevalence and severity since the late 19th century, outbreaks have now reemerged in multiple geographical regions over the past decade. Here, we review recent findings that address the role of superantigens in promoting a fitness advantage for S. pyogenes within human populations and discuss how superantigens may be suitable targets for vaccination strategies.

Scarlet Fever Upsurge in England and Molecular-Genetic Analysis in North-West London, 2014.

Scarlet fever notifications surged across the United Kingdom in spring 2014. Molecular epidemiologic investigation of Streptococcus pyogenes infections in North-West London highlighted increased emm4 and emm3 infections coincident with the upsurge. Unlike outbreaks in other countries, antimicrobial resistance was uncommon, highlighting an urgent need to better understand the drivers of scarlet fever activity.

An SEIQR model for childhood diseases.

It has been shown that the inclusion of an isolated class in the classical SIR model for childhood diseases can be responsible for self-sustained oscillations. Hence, the recurrent outbreaks of such diseases can be caused by autonomous, deterministic factors. We extend the model to include a latent class (i.e. individuals who are infected with the disease, but are not yet able to pass the disease to others) and study the resulting dynamics. The existence of Hopf bifurcations is shown for the model, as well as a homoclinic bifurcation for a perturbation to the model. For historical data on scarlet fever in England, our model agrees with the epidemiological data much more closely than the model without the latent class. For other childhood diseases, our model suggests that isolation is unlikely to be a major factor in sustained oscillations.

[Scarlet fever with multisystem organ failure and hypertrophic gastritis]. / Scarlatine compliquée d'une défaillance multiviscérale avec gastrite hypertrophique.

Scarlet fever is a rare disease in adult patients. We report a patient in whom scarlet fever was associated with hypertrophic gastritis and multiple organ failure. A 62-year-old woman presented with septic shock and multiple organ failure. Bacteriological survey was negative. Abdominal tomodensitometry showed an hypertrophic gastritis. Histological analysis demonstrated a non specific gastritis without any tumoral sign. Cefotaxime and amoxicillin led to improvement and hypertrophic gastritis progressively resolved. A sandpaper rash over the body with finger desquamation, elevation of antistreptolysin O and a recent contact with an infected grandson led to the diagnosis of scarlet fever. Due to antibiotic prescription, scarlet fever is now uncommon. Although classical, ENT or gastroenteritis presentations may be puzzling for the diagnosis of scarlet fever. As 150 years ago, diagnosis of scarlet fever is still a clinical challenge.

Increased level of circulating gamma/delta T cells in a patient with eosinophilic granuloma.

A patient with eosinophilic granuloma, histologically confirmed from open lung biopsy specimen, had a history of scarlet fever and a prominently high level of circulating gamma/delta T cells (25 percent) in comparison with normal levels (< 10 percent). Despite steroid therapy, the levels were persistently high. To our knowledge, this is the first report of an increased level of circulating gamma/delta T cells in a patient with eosinophilic granuloma.

[Comparative characteristics of the immunologic structure of children's collectives as regards scarlatina in different climatic zones]. / Sravnitel'naia kharakteristika immunologicheskoi struktury detskikh kollektivov v otnoshenii skarlatiny v raznykh klimaticheskikh zonakh

An immunological study (in respect to scarlet fever) of children in children's collective bodies was conducted in 1971-1972 simultaneously in two towns-Ashkhabad and Petrozavodsk located in the contrast climatic zones. Results of Dick's test and passive hemagglutination test indicated no significant differences in the level and intensity of antitoxic immunity in children of both cities; only during the autumn period, corresponding to the seasonal increase in the incidence of scarler fever in Ashkabad, the number of immune children in this town proved to be greater than in Petrozavodsk, this being connected with a more active process of "mute" immunization. At the same time differences were revealed in the level and dynamics of antibodies to the leading types of M-antigens of hemolytic streptococci. Consequently, a higher immunological reactivity of the organism in children in Ashkhabad (promoting rapid formation of both the antitoxic and the antimicrobial immunity and limiting of the spread of marked scarlet fever affections) underlied the differences in the level of scarlet fever morbidity in different climatic zones.

[Antibodies to erythrogenic toxin B in scarlatina patients]. / Issledovanie antitel k éritogennomu toksinu B u bol'nykh skarlatinoi

Coupled sera of 240 children suffering from scarlet fever obtained on the 1st-5th and 12th-15th days of the disease were examined in the PHA test with the A and B toxins. Antibodies to toxin B were revealed in 63-69% and to toxin A in 60-66% of the sera. In 64.5% of the cases the sera under study reacted simultaneously with both types of the toxin; antibodies to toxin B were contained in higher titres than to toxin A in 1/3 of the sera. The highest antibody titres to toxin B were revealed during summer.

[Patterns in the epidemic process of scarlet fever in various territories differing in respect of climate and geography]. / Zakonomernosti épidemicheskogo protsessa pri skarlatine na razlichnykh vlimato-geograficheskim otnoshenii territoriiakh

Observations carried out in Ashkhabad and Petrozavodsk permitted to reveal specific features of the epidemic process in scarlet fever at the territories differing in climato-geographic respect. This was expressed in a different level of morbidity, differences in the character of periodicity, seasonality and age structure of morbidity. Along with this there were noted differences in the spread of the carrier state of hemolytic streptococcus and of their biological properties, and also in the process of immunity formation in the population. The data obtained suggest that one of the causes of epidemiological differences in scarlet fever detected in the southern and the northern districts were peculiarities of the immunological reactivity of the population and a difference in the carrier state of the highly toxigenic streptococci.

[The OF characteristics of streptococci group A and immunity to streptococcal infection based on the results of OF and anti-OF tests]. / OF-kharakteristika streptokokkov gruppy A i immunitet k streptokokkovoi infektsii po rezul'tatam OF- i anti-OF-testov.

The influence of the OF activity of group A streptococci on their specific pathogenic properties has been shown, which is manifested by increased virulence of these streptococci for children of younger age groups and by a two times higher isolation rate of OF+ strains in tonsillitis than in scarlet fever. The possibility of the indirect evaluation of the content of anti-M-antibodies by the results of the anti-OF test has been revealed, which permits using this test instead of the bactericidal test, more complicated, in the study of immunity to infection induced by group A OF+ streptococci. Among the main methods of laboratory support of epidemiological surveillance on streptococcal infection, the introduction of the highly discriminating OF typing and the anti-OF test into practical use is recommended.

Hallazgos clínicos inusuales en un brote de escarlatina / Unusual clinical findings in an outbreak of scarlet fever

Introducción: la escarlatina es una enfermedad infecciosa producida por Streptococcus pyogenes que produce un cuadro característico de faringoamigdalitis y exantema. Su diagnóstico suele ser fácil, pero los casos atípicos pueden pasar desapercibidos o ser confundidos con otros cuadros. Pacientes y método: estudio descriptivo retrospectivo de los casos de escarlatina en la población pediátrica adscrita a un centro de salud en la temporada 2013/2014. Describimos la epidemiología, las características clínicas, las pruebas microbiológicas, el tratamiento y la presencia de recidivas. Resultados: se obtuvieron 91 casos, resultando una incidencia de 3,2%, de los que 76 fueron confirmados microbiológicamente con test rápido o cultivo. La edad media fue 4,15 años. Los principales motivos de consulta fueron 'fiebre y dolor de garganta' y 'fiebre y erupción cutánea'. Las alteraciones faríngeas más frecuentes fueron la hiperemia y petequias en paladar, y en pocos pacientes se encontró exudado amigdalar. Casi un 40% de pacientes tenían síntomas catarrales, 71 pacientes presentaban un exantema típico, y 20 uno atípico. La mayoría se trató con amoxicilina o penicilina durante diez días; 15 pacientes tuvieron recidivas. Conclusiones: de los datos obtenidos destacan el gran número de casos, la presencia de síntomas catarrales y la poca frecuencia de exudado amigdalar. Fue llamativa la variabilidad de los exantemas con hallazgos como eritrodermia extensa, urticaria, exantema macular, petequias en localizaciones atípicas y edema facial y de miembros. El test rápido en Atención Primaria permite, por su utilidad, el diagnóstico de casos dudosos (AU)

Introduction: scarlet fever is an infectious disease caused by Streptococcus pyogenes that manifests as a typical pharyngoamigdalitis and exanthema. Its diagnosis is usually easy, but atypical cases may go unnoticed. Patients and methodology: retrospective descriptive study of pediatric population assigned to a Primary Care center a health centre between 2013/2014. We define the epidemiology, clinical characteristics, microbiological tests, treat­ment and appearance of relapses. Results: 91 cases, resulting in an incidence of 3.2% of which 76 were confirmed microbiologically with a rapid test or culture. The average age was 4,15 years. The main reasons for consultation were 'fever and sore throat' and 'fever and rash'. The most common alterations were pharyingeal hyper­emia and petechiae on the palate and in a few patients we found tonsillar exudate. Almost 40% of patients had catarrhal symptoms. 71 patients showed a typical exanthema and 20 of them an atypical one. Most of them were treated with amoxicillin or penicillin for 10 days. 15 patients had recurrence. Conclusions: from the data obtained it is important to highlight the large amount of cases, the presence of catarrhal symptoms and the infrequency of tonsillar exudates. It was remarkable the variability of recurrences with findings such as extensive erythroderma, urticaria, macular rashes, atypically placed petechiae and facial and member edema. The rapid test on primary care units allows diagnosis on doubtful cases (AU)