6 VOJENSKÉ ZDRAVOTNICKÉ LISTY - SUPLEMENTUM Volume LXVIII, 1999, no. 1

NEW AND RE-EMERGING INFECTIOUS DISEASES

Václav DOSTAL, Karel HONEGR, Stanislav PLÍŠEK Infectious Diseases Department, University Hospital, Hradec Králové

Infectious diseases traverse the usual boundaries quirement, the Specialty of infectious diseases be- established by medical Specialists. All organ sys- comeS the last disciplinary domain of general me- tems may be involved, and all physicians caring for dicine. patients may have to deal with infected patients. lronically, many of the forces that contribute to the Infectious diseases remain leading cause of mor- appearance of new diseases and emergence of old bidity and mortality throughout the world primarily ones are created by human activity - in many in- because known measures of control and therapy stances by what we consider extraordinary achieve- are not applied. In technically advanced countries, ments. We have underestimated the complexity of the pestilences of antiquity no longer occur. Yet, even our environment and the capacity of other species in these areas infectious diseases remain important adapt and evolve. We have overestimated the power contributors to illness and death. of tools, such as antimicrobials, pesticides, and vac- Among clinical specialty areas, that of infectious cines to free us of disease. We have failed to re- diseases is remarkable in being non-Systemic in cognize that events in plants and animals can teach orientation. The specialist in infectious diseases must us and affect our health. We have paid little atten- be prepared to deal with involvement in any organ, tion to the geoclimatic influences on health. We System, or region of the body. A patient comes to have too often ignored the social, economic, and po- See a physician because of a Sore throat, not be- litical contributions to disease. Several general con- cause of caused by pyo- cepts can help focus your attention to infectious genes. In assessing illness, he must be capable of diseases. taking into account age, Sex, and genetic constitu- Disease emergence is complex; often several fac- tion; nutritonal, hormonal, and metabolic Status; the tors must change sequentially or simultaneously to consequences of trauma, surgery, and other physical allow a disease to emerge. Infectious diseases are or chemical agents; and the effects of neoplastic, dynamic. New will continue to appear, pos- degenerative, and hypersensitive States. In this re- sibly at increasing rates. Volume LXVIII, 1999, no. 1 VOJENSKÉ ZDRAVOTNICKÉ LISTY - SUPLEMENTUM 7

Known infectious diseases will change in distribu- plant recipients who, due to immunosuppression, are tion, Severity and frequency. susceptible to opportunistic infections. Most new infections are not caused by novel pathogens. Some old organisms have apparently adopted Human activities are the most potent factors new tactics. is the result of leading to the appearance of new infectious di- a previously unknown toxin, produced by the fa- seases and the change in known infectious diseases. miliar pathogen, Staphylococcus aureus. To further Social, economic, climatic, and political forces shape confuse us some old infections are appearing in new disease patterns and influence emergence. clinical guises, such as atypical measles in adoles- Interventions to control infections can paradoxic- cents and young adults who received measles vac- ally increase the burden of disease. cine prior to 1967. Infant botulism, first recognized Understanding disease emergence requires look- as a clinical entity distinct from food-borne botulism ing beyond the organism to the milieu, the ecosys- in 1976, presents the picture of the infant between tem, and society. A global perspective is essential. the ages of one and six months collapsing with a The pathogens identified in most of the newly neuroparalytic illness, fiaccidity, and hypotonia due named diseases, such as Legionnaires’ disease, to botulinum growing in the intestinal toxic shock syndrome, , and AIDS tract and liberating a potent toxin. are not novel pathogens that appeared de novo What are the causes for these changing pat- just prior to the recognition of disease. In most terns of infectious diseases? At least three factors instances of new diseases, the pathogens have can be implicated: been present for centuries or longer. The process 1) changes in lifestyle, including sexual behaviour, that leads to the recognition and naming of a travel patterns, dietary trends, leisure activity, and disease often involves social and economic, as well composition of the work force, have impacted as scientific events. Factors that favor recognition on disease patterns as have of a disease as new are several: clustering of cases 2) immigration and in time or space; increase in prevalence; distinctive 3) the effects of medical progress. signs, symptoms or laboratory findings; short incub- ation; rapid progression; high mortality and so on. History teaches that from time to time it is Changing patterns of Infectious diseases worthwhile looking back at where we have been to better understand where we are and where we Type Of Change Example may be going. During the last 20-30 years, some of New diseases AIDS the most evident, striking, and interesting changes in patterns of disease have occured among those Cryptosporidiosis due to transmissible agents. The increasing human New geographic range Malaria in American population facilitates transmission of disease from for old disease travelers person to person with epidemiologic changes or Chagas’disease in increased virulence, and the expansion of the po- Central America pulation into new ecologic niches brings people in immigrants contact with new potential disease pathogens and New populations at risk in renal the emergence of new disease problems. transplant recipients What types of change have occured in the pat- Giardiasis in day-care terns of infectious diseases? The most dramatic is centers the occasional recognition of so-called new diseases. Some of these are, in fact, old illnesses for which a New tricks for old Toxic shock syndrome cause has been recognized. Diarrhea due to Cam- „bugs“ Pseudomonas pylobacter, unheard of 30 years ago and now con- sidered among the most common causes of bac- New faces for old Atypical measles terial enteritis, serves as an example. diseases Infant botulism Some diseases, on the other hand, do seem to New ecologic niches for Sneaker—associated be truly new or at least more common than was old ,,bugs“ Pseudomonas thought. AIDS is the most obvious and previously osteomyelitis lamentable example. ln addition, Some old diseases Hot tub folliculitis are now appearing in new geographic locales. Malaria is being seen increasingly in the United New modes of Rabies following States civilian population, which is no surprise since transmission corneal transplantation millions of Americans each year are traveling to Creutzfeld-Jakob tropical countries. We must also remember new po- disease in recipients of pulations at risk, such as renal and cardiac trans- human growth hormone 3 VOJENSKÉ ZDRAVOTNICKÉ LISTY - SUPLEMENTUM Volume LXVIII, 1999, no. 1

As recently as 20-30 years ago, none of the en- plays a relatively minor role, although for other con- tities Shown On the left-hand Side of the balance ditions, Such as infection with tracho- was part of our medical vocabulary. While acquiring matis, sexual transmission is the major route of many new afflictions, we got rid of one very old one acquisition. - Smallpox. NOW - YEARS AGO IN OUT AIDS AIDS Smallpox Scabies Babesiosis Amebiasis Lassa fever Giardiasis Lyme disease Toxic shock sy Infant botulism Hepatitis B, G/?l Kawasaki disease Chlamydia infection Rotavirus diarrhea Campylobacteriosis LGV Chlamydia pneumonia Ureaplasma urethritis Hepatitis C, D, E, G Cytomegalovirus Legionnaires’ disease infection Campylobacter enteritis Herpes genitalis and others and others

Kawasaki disease, which is probably of infectious Changing Lifestyles and New Populations at Risk etiology, produces in children symptoms of fever, skin Cryptosporidium is a protozoan parasite of the and mucous membrane lesions, lymph node en- gastrointestinal tract that only recently has been largement, and sometimes aneurysms of the coro- identified as a cause of human gastrointestinal nary arteries. Recent evidence has implicated retro- disease. It is common in immunologically normal viruses as a possible etiology for this fascinating persons in whom it produces a self-limiting illness, entity. as was described in the day-care-center outbreak. Legionnaires’ disease, first recognized during the The advancing average age of the population and 1976 epidemic in Philadelphia, is now known to be the growing use of nursing homes has generated a cause of sporadic as well as epidemic pneumonia. another new population at risk. Nursing home out- Another new entry to our medical vocabulary is breaks of influenza, tuberculosis, varicella-zoster, amebic meningoencephalitis, a rare but devastating a variety of diarrheal illnesses, and meningitis have infection of the central nervous system. It affects all been reported. people swimming and diving in freshwater lakes Whirlpools, spas, and hot tubs, which were virtu- and is caused by free-living amebas of the genus ally nonexistent a few years ago, are now widely en- Naegleria. joyed by many people privately at home and in a va- In recent years we have also come to know the riety of health and leisure clubs. With new pleasures causes of some older diseases such as - come new problems, for example Pseudomonas fol- -related colitis arising from a toxin produced by the Iiculitis as the new entity. bacterium Clostridium difficile. We have also Ieamed Other unusual infections that have been as- that cat scratch disease is traceable to a small sociated with hot tubs and whirlpools include Pon- gram-negative bacterium. tiac fever due to Legionella pneumophila and Acanth- amoeba keratitis. Leisure offers another options also. Trips to the Changes in sexually transmitted diseases mountains and woods bring contacts with the beauties of mother nature, but also contacts with We now recognize many more than the traditional one of nature's less appealing creatures - the tick - five venereal diseases taught 20-30 years ago. The the vector of the Borrelia causing Lyme disease. weight of all of these afflictions has tipped the balance. A variety of microorganisms can be trans- mitted during sexual contact. They differ markedly Impact of Travel in their taxonomy, virulence factors, growth re- Free people are traveling abroad with increasing quirements, and response to therapy. They are frequency including exotic parts of the world where grouped together because sexual transmission malaria, schistosomiasis, and filariasis are endemic. plays an important role in their overall epidemiology. In addition to more pleasant Souvenirs, some are None of the sexually transmitted diseases (STD) is returning with infections that first appear on arrival acquired solely via coitus. In some cases (e.g., and that, because of their rarity in our country, are shigellosis and candidiasis), sexual transmission often not thought of by physicians. Volume LXVIII, 1999, no. 1 VOJENSKÉ ZDRAVOTNICKÉ LISTY - SUPLEMENTUM 9

Impact of Medical Progress now known to be caused by transmissible agents ' Medical progress continues to bring many bene- called prions. The other is scrapie, a disease of fits, but it has also brought with it new infectious sheep. They are very small agents capable of replic- disease complications and new modes and pat- ating in mammalian cells but containing no nucleic terns of disease transmission. acids. They appear to be small proteins many times smaller than the smallest viruses. Diseases in which Opportunistic infections in organ transplant prions have been implicated are classified as slow recipients infections characterized by very long incubation Bacterial infections complicating foreign body im- periods of months, years, or even decades in which plants: the host is without symptoms. Thus, we see that . heart valves, prosthetic joints, cerebrospinal fluid one dramatic change in the last 20-30 years is our shunts, hemodialysis and peritoneal dialysis recognition of an entirely novel form of infectious access sites, intrauterine devices, fetal scalp agent and a change in our understanding about monitors, central venous catheters the pathophysiology of infectious diseases and the . Fungemia complicating total parenteral nutrition rate at which infections may evolve. . Bacteremia due to contaminated blood products . Mycobacterial following augmentation What can we learn from these changing patterns mammoplasty implants of infectious diseases? Surely we have ample . Post-cardiac bypass mononucleosis syndrome proof of the dynamic nature of medicine. It would . Pneumonia due to contaminated inhalation be prudent for those involved in medical education therapy equipment to be cognizant of these dramatic changes that . AIDS following transfusion and organ have occurred in so brief a time as they struggle to transplantation make curricula relevant. Who could have imagined . Hepatitis B /G?/ and HIV infection after artificial AIDS or prions? Perhaps as we study and learn insemination from the changing patterns of disease, we shall . Creutzfeldt-Jakob disease in recipients of human find the clues and lessons that will enable us to growth hormone achieve greater successes. . Creutzfeldt-Jakob disease following human dura mater grafting . Rabies and Creutzfeldt-Jakob disease after corneal grafting . Acanthamoeba keratitis in contact lens wearers Correspondence: Doc. MUDr. Václav Dostál Infectious Diseases Department New Pathogenic Agents University Hospital Creutzfeldt-Jakob disease is one of two diseases Hradec Králové

Presented at the lntemational NATO Symposium ,,Army and Communicable Diseases Control“, September 21-25, 1998, Hradec Králové, Czech Republic