Update on the global epidemiology of tuberculosis

Because the international community neglected tuberculosis, developing countries did not mirror the decline in incidence of the disease seen in the industrialized world following the discovery of antituberculosis drugs. During the 1990s, developing countries will experience an estimated 90 million new cases of tuberculosis and 30 million deaths from the disease. Most new infections and deaths occur in Asia and Africa. In developing countries, socioeconomic conditions foster the spread of the disease, and inadequate health care systems mean that patients are not diagnosed rapidly and are not treated effectively until cured. The HIV epidemic is also contributing to the prevalence of tuberculosis in developing countries because of the large pool of coinfected people. Tuberculosis is the most frequent opportunistic disease in people with HIV/AIDS living in Africa, Latin America, and southeast Asia. A new wave of tuberculosis notifications and deaths has also occurred in the former socialist countries of central and eastern Europe because of war, conflict, impaired nutrition, stress, deterioration of the public health system following the dissolution of the Soviet Union, and a severe lack of drugs. In the US, notification increased during 1985-93 due to factors such as poor control programs. Rates have also increased or failed to decline in western Europe, and this situation has been linked with an increased number of cases among the foreign-born population. The extent and severity of drug resistance is unknown but the high rates of initial drug resistance, acquired drug resistance, and multi-drug resistance have been found. The World Health Organization is attempting to describe the true extent of the problem. Meanwhile the control situation is improving slowly but inadequately, with district-based programs giving the most hope. The extent of multi-drug resistance will have an important effect on the epidemiology of this disease. An effective eradication strategy exists but depends upon sustained political commitment.     

Epidemiological trend in tuberculosis in the Italian region of Liguria: impact of immigration and AIDS

BACKGROUND: Tuberculosis (TB) uniformly decreased in all industrialized countries from 1950 to 1985. However, since 1985 an upsurge of the disease has been observed, probably due to the increases in AIDS and immigration. It is for this reason that in the last decade all industrialized countries have intensified their controls on TB and a new reduction has been recently observed. METHODS: In this study we collected epidemiological data (mortalities and reported cases) for the region of Liguria over the last 15 years. We then calculated the incidence rate of TB per 100,000 residents according to age, HIV infection and nationality, making a distinction between European Union (EU) citizens and immigrants coming from countries outside the EU. RESULTS: The rate of mortality, after the last peak at the end of the Second World War, has progressively decreased from 1946 to today, so much so that presently we record fewer than two cases per 100,000 people. We observed a consistent downward trend in the incidence rate up to 1987, but from 1988 onwards this trend stopped and, in subsequent years, we detected an increase in the incidence rate, which peaked in 1996. This led to increased interventions, which has resulted in a considerably decreased overall rate of cases of TB during the last few years. The number of TB cases specifically among foreigners increased considerably during the last 5 years, whereas there was a drastic reduction in the number of total TB cases, as well as an interesting reduction in AIDS cases. During the same period there was a progressive decrease in tuberculin skin positivity in all school classes. CONCLUSIONS: The reduction in TB notifications is probably due to an increase in surveillance and control of social and health conditions. These results show that immigrant workers are considered to be a high-risk group, whereas the risk has progressively decreased in the HIV group.     

Exceptional epidemics: AIDS still deserves a global response

There has been a renewed debate over whether AIDS deserves an exceptional response. We argue that as AIDS is having differentiated impacts depending on the scale of the epidemic, and population groups impacted, and so responses must be tailored accordingly. AIDS is exceptional, but not everywhere. Exceptionalism developed as a Western reaction to a once poorly understood epidemic, but remains relevant in the current multi-dimensional global response. The attack on AIDS exceptionalism has arisen because of the amount of funding targeted to the disease and the belief that AIDS activists prioritize it above other health issues. The strongest detractors of exceptionalism claim that the AIDS response has undermined health systems in developing countries.     

Resurgence of diphtheria

Following the introduction of routine immunization with diphtheria toxoid in the 1940s and 1950s, diphtheria incidence declined dramatically in countries of the industrialized world. At the beginning of the 1980s many of these countries were progressing toward elimination of the disease. However, since the mid-1980s there has been a striking resurgence of diphtheria in several countries of Eastern Europe. For 1993, WHO received reports of 15,211 diphtheria cases in Russia and 2,987 cases in Ukraine. The main reasons for the return of diphtheria in these countries were: decreasing immunization coverage among infants and children waning immunity to diphtheria in adults, movements of the population during the last few years, and an irregular supply of vaccines. The outbreak spread to neighboring countries and in 1993 cases were reported in Azerbaijan, Belarus, Estonia, Finland, Kazakhstan, Latvia, Lithuania, Poland, Tajikistan, Turkey, and Uzbekistan. Epidemiological patterns of diphtheria are changing in developing countries, and the disease seems to be following patterns seen in industrialized countries 30 to 40 years ago. In developing countries, routine immunization against diphtheria was introduced in the late 1970s with the Expanded Programme on Immunization. In these countries, coverage of infants with 3 doses of diphtheria toxoid reached 46% in 1985, and 79% in 1992. Recent diphtheria outbreaks in Algeria, China, Ecuator, Jordan, Lesotho and Sudan demonstrate a shift in the age distribution of cases to older children and adults. Rapid clinical and public health responses are required to control diphtheria outbreaks. Three major measures are indicated: high immunization coverage of target groups, prompt diagnosis and management of diphtheria cases, and rapid identification of close contacts with their effective management to prevent secondary cases.     

Diphtheria: Changing patterns in the developing world and the industrialized world

In the past, diphtheria was considered one of the most serious childhood diseases because it took a heavy toll in health and life among preschool-aged children. Prior to the widespread availability of diphtheria toxoid, nearly 70% of cases were in children younger than 15 years of age. In the industrialized countries, immunization against diphtheria became widespread in the 1940s and 1950s. This led to a marked decrease in the incidence of diphtheria. There was also a decrease in circulating toxigenicCorynebacterium diphtheriae organisms, resulting in less natural boosting of antibody levels. This has led to gaps in the immunity of the adult population. Since 1990, diphtheria has made a spectacular comeback in several European countries, with a high proportion of cases in adults. In developing countries, immunization of infants with diphtheria toxoid was introduced within the Expanded Programme on Immunization in the late 1970s. Coverage rose slowly to 46% in 1985 and 79% in 1992. Because the pool of immunized persons is not yet large, the process of maintaining immunity still operates through natural mechanisms, including frequent skin infections caused byC. diphtheriae. But recently, several developing countries where coverage has been high for 5–10 years have reported diphtheria outbreaks. These outbreaks have been characterized by high case fatality rates, a large proportion of patients with complications, and their occurrence in both young and older age groups. In all countries, priority should be given to efforts to reach at least 90% coverage with three doses of diphtheria toxoid in children below one year of age. In countries where diphtheria has been successfully controlled, immunity levels should be maintained by booster doses.     

Epidemiology of sexually transmitted diseases: the global picture

Sexually transmitted diseases (STD) are now the commonest group of notifiable infectious diseases in most countries, particularly in the age group of 15 to 50 years and in infants. Their control is important considering the high incidence of acute infections, complications and sequelae, their socioeconomic impact, and their role in increasing transmission of the human immunodeficiency virus (HIV). The worldwide incidence of major bacterial and viral STD is estimated at over 125 million cases yearly. STD are hyperendemic in many developing countries. In industrialized countries, the bacterial STD (syphilis, gonorrhoea, chancroid) declined from the peak during the Second World War till up to the late fifties, then increased during the sixties and early seventies, and they have been decreasing again from the late seventies till the present. In the industrialized world, diseases due to Chlamydia trachomatis, genital herpes virus, human papillomaviruses and human immunodeficiency virus are now more important than the classical bacterial ones; both groups remain major health problems in most developing countries. Infection rates are similar in both women and men, but women and infants bear the major burden of complications and serious sequelae. Infertility and ectopic pregnancies are often a consequence of pelvic inflammatory disease, and are preventable. Sexually transmitted diseases in pregnant women can result in prematurity, stillbirth and neonatal infections. In many areas 1-5% of newborns are at risk of gonococcal ophthalmia neonatorum, a blinding disease; congenital syphilis causes up to 25% of perinatal mortality. Genital and anal cancers (especially cervical cancer) are associated with viral sexually transmitted diseases (genital human papillomavirus and herpes virus infections). Urethral stricture and infertility are frequent sequelae in men.     

As AIDS cases wane, pressure grows for reporting HIV infections

The Centers for Disease Control and Prevention (CDC) published new data demonstrating significant declines in the number of AIDS cases and deaths. This evidence is spurring support for nationwide HIV and AIDS surveillance. Currently, all States track AIDS cases and thirty States also track new HIV infections among adults and adolescents. California, New York, Pennsylvania, and Illinois, States with very high prevalence rates, are not among those States tracking new infections. According to the CDC, tracking AIDS cases alone is not sufficient for determining how public prevention and treatment funds should be allocated. Some AIDS policy advocates oppose HIV surveillance if it involves recording the names of those infected. Since 1985, the CDC has reviewed the value of asking all States to adopt some form of HIV surveillance. When the CDC recommended State tracking in 1993, there were strong objections raised by AIDS policy advocates. Following a May 1997 meeting with public health experts, health care providers, and policy advocates, the CDC reported growing support for HIV surveillance. Public health experts are examining the possibility of developing a unique identifier system that would eliminate the need to record individual names.     

Opportunistic infections in HIV-positive patients hospitalized in the Clinic of Infectious Diseases AMG

Opportunistic infections are one of the major problem among HIV infected patients still connected with high mortality. The aim of the investigation is to evaluate the incidence and mortality from opportunistic infections in HIV infected population in Pomeranian region of Poland. The paper presents analysis of incidence of opportunistic infections among 141 AIDS patients hospitalised in Clinic for Infectious Diseases in Gdańsk from 1988 to 2001/June/. In examined group 179 opportunistic infections were diagnosed. Most frequent was oesophageal candidiasis 58%, tuberculosis 29%, pneumocystis carinii pneumonia 21% and central nervous system toxoplasmosis 13%. The occurrence of opportunistic infections depends on CD4 count and rises with CD4 decline. Opportunistic infections were the reason of death in 33 from 74 cases/45%/. CONCLUSIONS: In examined group 28% of patients did not know about HIV infection when first opportunistic infection was diagnosed. Most frequent opportunistic infections in AIDS patients were oesophageal candidiasis, tuberculosis, pneumocystis carinii pneumonia and toxoplasmosis. In 98% of cases opportunistic infection developed when no HAART nor infection prophylaxis was administered. Opportunistic infection was the reason of death in 45% of cases, the most frequent were PCP and CNS toxoplasmosis.     

World Health Organization global oral health strategies for oral health promotion and disease prevention in the twenty-first century

Despite great improvements in oral health in the past decades, oral disease remains a major public health problem worldwide. The burden of oral disease is particularly high among the disadvantaged population groups in both developing and developed countries. The pattern of oral disease reflects distinct risk profiles across countries that are related to living conditions, lifestyles, environmental factors, and the availability and accessibility of oral health services. In several developing countries, people at large do not benefit from preventive oral health programmes. It is expected that the incidence of dental caries will increase in the near future in many of these countries as a result of growing consumption of sugars and inadequate exposure to fluorides. With the rising use of tobacco in developing countries, the risk of periodontal disease, tooth loss and oral cancer may therefore increase. Several oral diseases are linked to non-communicable chronic diseases or conditions that share common risk factors, such as diabetes, obesity and cancer. Similarly, general diseases often have oral manifestations (e.g. diabetes or HIV/AIDS). Worldwide strengthening of public health programmes through implementation of effective oral disease prevention measures and health promotion is urgently needed, and use of common risk factors approaches should integrate oral health within national health programmes. The challenges to oral health improvement are particularly high in developing countries. The World Health Organization Global Oral Health Programme formulates policies and actions for the improvement of oral health, strategies that are fully integrated with chronic disease prevention and general health promotion. At the 60th World Health Assembly in 2007, the WHO Member States agreed on an action plan for oral health and integrated disease prevention, thereby confirming the approach of the Oral Health Programme. The policy forms the basis for future development of oral health programmes.     

Dihydropteroate synthase gene mutations in Pneumocystis and sulfa resistance

Pneumocystis pneumonia (PCP) remains a major cause of illness and death in HIV-infected persons. Sulfa drugs, trimethoprim-sulfamethoxazole (TMP-SMX) and dapsone are mainstays of PCP treatment and prophylaxis. While prophylaxis has reduced the incidence of PCP, its use has raised concerns about development of resistant organisms. The inability to culture human Pneumocystis, Pneumocystis jirovecii, in a standardized culture system prevents routine susceptibility testing and detection of drug resistance. In other microorganisms, sulfa drug resistance has resulted from specific point mutations in the dihydropteroate synthase (DHPS) gene. Similar mutations have been observed in P. jirovecii. Studies have consistently demonstrated a significant association between the use of sulfa drugs for PCP prophylaxis and DHPS gene mutations. Whether these mutations confer resistance to TMP-SMX or dapsone plus trimethoprim for PCP treatment remains unclear. We review studies of DHPS mutations in P. jirovecii and summarize the evidence for resistance to sulfamethoxazole and dapsone.