Despite high vaccine coverage, pertussis remains a global health concern. Recently, the incidence of infection has risen in Europe and other developed countries. Healthcare providers should be aware of the possibility of pertussis not only among unvaccinated infants but also among adolescents and adults, in whom pertussis often is misdiagnosed.

INTRODUCTION: Rotaviruses are a leading cause of diarrheal mortality in children less than five years old. Mixed forms with other intestinal pathogens have been reported, interfering with the severity and outcome of the illness. AIM: The aim of this article is to analyze the characteristics of mixed infections among rotaviruses and other intestinal pathogens. MATERIALS AND METHODS: Twenty-seven patients up to 5 years of age, diagnosed with a co-infection from the rotavirus group and other intestinal pathogens were analyzed during the period from March, 2016 to December, 2017. A clinical epidemiologic study was conducted. The diagnosis was made by stool cultures for bacterial pathogens/feces analyses for viral antigens in the microbiology/virus laboratory of the St. Marina University Hospital, Varna. Statistic methods were used for data processing. RESULTS: For the aforementioned period, 483 patients, up to 5 years of age, with rotaviral gastroenteritis were hospitalized. Mixed forms of intestinal infection were registered in 27 children (5.59%). Early childhood (between 1 to 3 years of age) was the most commonly affected age group. Cases were separated into two groups: rotavirus-virus association and rotavirus-bacterium association. Cases with rotavirus-virus association were more predominant (55.6%) than rotavirus-bacterium ones (44.4%). The clinical presentation included fever, vomiting, diarrhea, and lasted 6.53±1.53 days among the patients in the first studied group. In rotavirus-bacterium mixed infections vomiting was not a generally present symptom, but distinct complications ordinary occurred (83.33%) and the average hospitalization period was 10±1.98 days. CONCLUSION: Mixed infections including rotavirus and other intestinal pathogens are rarely diagnosed and mainly affect young children. Compared with rotavirus-bacterium association, rotavirus-virus association is more commonly registered, its clinical course is milder, the prognosis of the disease is auspicious and the in-patient stay is shorter.