A complex interplay of environmental and human factors, including ecological, genetic, political and socioeconomic factors, is responsible for the emergence and re-emergence of infectious diseases. These factors often have a distinct effect on children and, as a result, emerging infections can have unique impacts on younger populations in terms of both physical health and mental as well as social wellbeing. Children are the most vulnerable members of our society. In order to best protect them from the impact of emerging infectious diseases, it is imperative to understand how factors that determine disease emergence and emerging diseases themselves can affect the young. This will allow us to focus on the most appropriate measures to not only prevent infection of pediatric populations but also prepare for the treatment and care of children when an infectious disease emerges. Influenza is a prototypical emerging/re-emerging infectious disease. Epidemic influenza re-emerges annually in periods between influenza pandemics. Both epidemic and pandemic influenza can have considerable impacts on the wellbeing of children. For over a decade, we have anticipated the mutation of avian influenza (H5N1) into a virus that can be efficiently transmitted between humans. This has resulted in substantial efforts to prepare for a virulent influenza pandemic. Although the pandemic potential of avian influenza has not (yet) been realized, efforts to prepare for a widespread pandemic have not been in vain. The unexpected emergence and rapid spread of the swine flu [influenza A(H1N1)v] has resulted in a worldwide pandemic that has already had profound effects on children and adults. Schools, day care centers, modern transport and international travel have all facilitated the spread of this new influenza strain. Swine flu exemplifies well how environmental and human factors interact to result in the emergence of an infectious disease with unique impacts on children.
The epidemiology of invasive fungal infections is evolving. Yeasts other than Candida albicans and moulds other than Aspergillus fumigatus have emerged as significant causes of invasive mycoses in severely immunocompromised patients. Whereas in some instances these changes may be related to medical interventions, such as the use of prophylactic antifungal agents, in the majority of cases, they seem to be a consequence of changes in the host. More severe immunosuppression or different types of immune suppression impact both risk and the infections that occur. These factors have altered the epidemiology of infection in organ transplant recipients, premature newborns and critically ill patients. Our review discusses the epidemiology of some fungal infections that have emerged in the past few years, with an emphasis on the potential factors associated with their emergence and on practical implications of these epidemiological changes. In addition, some special characteristics noted in children and neonates are addressed separately.
Tick-borne infections occur worldwide and have been well known for more than 100 years. Some tick-borne diseases are very common while others are extremely rare. Modern molecular genetic techniques (and the wider availability of polymerase chain reaction) have lead to the discovery and classification of new pathogenic agents, especially for the order of Rickettsiales. This review deals with viral, bacterial and protozoal agents that may cause human disease. Most tick bites, and hence the tick-borne diseases, occur during the warmer time of the year. With respect to the natural reservoirs, there is a strong geographic variation among different tick-borne diseases. The history of a tick bite is not always reliable, because a tick bite may go unnoticed. The most common diseases are Lyme borreliosis and tick-borne encephalitis due to a flavivirus. The viral infections more often have neurologic signs of encephalitis, while the rikettsial infections are characterized by fever (biphasic), systemic symptoms of infection and often a rash with petechiae. Some of the tick-borne diseases are preventable by immunization, such as tick-borne encephalitis. The non-viral infections should be treated early with antibiotics, mostly following clinical suspicion, to achieve a satisfactory outcome. Either due to the virulence of the pathogen, non-utilization of preventive measures or due to delayed diagnosis and treatment, mortality rates may vary, but the tick-borne infections still cost lives.