Vertical transmission of human immunodeficiency virus: six years of development 1987-1992)

BACKGROUND: According to World Health Organization estimates, from the beginning of the epidemics to the end of 1994, the number of children infected by human immunodeficiency virus (HIV) was 1.5 million. This paper describes the evolution of some clinical and epidemiologic characteristics of vertically transmitted HIV infection. PATIENTS AND METHODS: All children born to HIV-infected mothers who delivered at a university hospital in Barcelona, Spain, between 1987 and 1992, were included in the study. Rates of HIV vertical transmission, HIV infection incidence and mortality due to HIV were estimated, and trends for the study period analyzed. Odds ratios were used to assess associations between variables. RESULTS: 192 newborns were identified and allocated, with respect to the year of birth, in three cohorts of 71, 58 and 63 children. Overall HIV vertical transmission rate was 16.5% and did not differ between cohorts. Infection incidence density rates increased over time (0.2, 4.9 and 8.1 cases/100 child-years, respectively; p = 0.016), while incubation periods decreased significantly (248, 103 and 114 days; p = 0.0004). There were no changes in mortality density rates (2.2 deaths/100 child-years). Regarding mothers' characteristics, a significant temporal trend (p < 0.001) for being older at delivery, belonging to the heterosexual transmission group and having symptomatic infection was observed over time. CONCLUSIONS: Certain clinical and epidemiologic aspects of HIV vertical transmission have changed over time, however the number of new cases has remained fairly constant. In our setting, both early diagnosis and clinical management of these children have improved, but primary prevention for HIV vertical transmission has not been effective. Better counselling for HIV-infected women of childbearing age is needed.     

Should we patch corneal erosions?

This prospective study was performed to investigate epidemiological characteristics in terms of the age- and sex-specific incidence in patients with perforated and nonperforated appendicitis. The study population comprised 1486 consecutive patients who underwent appendectomy for suspected acute appendicitis between 1989 and 1993. Two patient cohorts [n = 544 (37%)] were analyzed with regard to prehospitalization duration of symptoms and in-hospital observation time. The crude incidence of acute appendicitis was 86 per 100,000 per year. Although the incidence of nonperforated appendicitis was highest among adolescents and young adults (13-40 years of age), perforated appendicitis occurred at almost the same incidence in all sex and age groups. The diagnostic accuracy was 76%. Perforated appendicitis occurred in 19%, with higher rates in small children and the elderly, irrespective of gender. A high diagnostic accuracy was not associated with an increased rate of perforation. In small children and the elderly, the diagnostic accuracy was low and the perforation rate high. Patients with perforation had a significantly longer duration of symptoms as well as in-hospital observation time than did patients with nonperforated appendicitis. Perforated appendicitis showed a different incidence pattern than nonperforated appendicitis and was associated with a significantly longer duration of symptoms and in-hospital observation time, probably due to patient-related factors. We suggest this observation deserves attention regarding clinical diagnosis and treatment decision-making for patients with suspected acute appendicitis.     

A measles epidemic controlled by immunisation

AIM: In 1997, an immunisation campaign, using measles-mumps-rubella vaccine, was planned for children aged 2-10 years to prevent a measles epidemic predicted by mathematical modelling. The epidemic started before the campaign and is described here. METHOD: Measles hospitalisation, notification and laboratory data were combined. RESULTS: The epidemic started in April 1997 and was largely over by January 1998. No deaths were identified and only one hospitalisation was coded as measles encephalitis, compared to seven deaths and ten cases of measles encephalitis in the 1991 epidemic. For the 12 months from 1 March 1997 there were 2,169 (60 per 100,000) measles cases identified, 314 (9 per 100,000) of whom were hospitalised. Two-thirds of hospitalised cases were notified. The age-standardised measles incidence rates were 33, 34, and 174 per 100,000 for Europeans, Maori and Pacific people, respectively. The respective age-standardised hospitalisation rates were 4, 9 and 32 per 100,000. Measles incidence was highest for under one-year-olds (904 per 100,000) and low for 11-16 year-olds (27 per 100,000)--the cohort previously offered a second vaccine dose. Most cases were aged 10 years and under, and this group were the main drivers of virus transmission. CONCLUSIONS: The immunisation campaign prevented 90-95% of predicted cases. The campaign was appropriately targeted at children aged 10 years and under.     

A secular increase in the incidence of juvenile diabetes mellitus

Data from a 1973 survey of diabetes mellitus among schoolchildren in Michigan have been analyzed to derive age-specific incidence and prevalence rates. The annual incidence of new cases of diabetes is approximately 20/100,000 children from age four through age 17, with the highest incidence rates at age nine through age 12. The prevalence rates to be expected, if the most recent incidence rates persist, are approximately 50/100,000 at age five, 150/100,000 at age ten, 270/100,000 at age 15, and 325/100,000 by age 18. The incidence rate of diabetes in Michigan children appears to have doubled between 1959 and 1972. Data from Erie County, New York, suggest that this secular trend has been evident since 1949, and data from Norway suggest that the trend could be noted 50 to 70 years ago.     

Spectrum of 2,836 cases of invasive bacterial or fungal infections in children: results of prospective nationwide five-year surveillance in Finland. Finnish Pediatric Invasive Infection Study Group

In a prospective nationwide laboratory-based surveillance study of all invasive bacterial and fungal infections among children < 16 years of age, 2,836 clinical cases were registered during the 5-year period 1985-1989. Of these cases, 136 were polymicrobial. During the study period, nationwide administration of Haemophilus influenzae type b conjugate vaccine reduced the incidence rates of invasive infection caused by this organism. The most common clinical diagnosis (48% of cases) was bacteremia without an identified focus of infection. The age-specific annual incidence rates of all invasive infections in children < or = 15 years of age, in children < or = 4 years of age, in children < or = 1 year of age, and in children < or = 28 days of age were 55.8, 141.4, 272.7, and 2,749.0 cases/100,000 person-years, respectively. Thirty percent of the children in the study had an underlying condition predisposing to infection. The case-fatality rate was 4.1% for all cases of invasive infection.     

Pediatric rheumatology in the United Kingdom: data from the British Pediatric Rheumatology Group National Diagnostic Register

OBJECTIVE: To establish a computerized national diagnostic register for pediatric rheumatology in the UK; to describe the demography and diagnostic classification of children referred to pediatric rheumatology clinics; to estimate the current incidence of juvenile arthritis (JA) in the UK. METHODS: A diagnostic register was established in 1989: 23 centers have contributed data on all new cases seen since they joined the register; 18 centers have also contributed data on all current attenders. For 2 centers with well defined catchment areas, the incidence of JA was estimated. RESULTS: A total of 4948 cases were registered, of whom 2962 (60%) were female. 1991 (40%) had a diagnosis of JA. The 2nd largest category was mechanical/orthopedic problems (24%). Pauciarticular juvenile chronic arthritis was the most common subtype of JA. Seropositive RA was rare. Tertiary referral centers saw proportionately more JA and district general hospitals saw proportionately more mechanical problems. The annual incidence rate for JA from 2 centers was 10/100,000, and for all rheumatic disorders was 32-42/100,000 children under age 16. CONCLUSION: The relative proportion of patient diagnoses varies between centers. Nevertheless, the incidence of hospital referred JA seems very uniform.     

Opportunistic infections of the central nervous system in the course of acquired immune deficiency syndrome (AIDS). Morphological analysis of 172 cases

A neuropathological analysis of 172 cases of AIDS in adults was carried out, to determine the occurrence and nature of the opportunistic infections of the central nervous system (CNS). The material comprised 155 cases of men, and 17 women. Mean age of patients was 38 years. Collection under study originated from the period between 1987 and 1997. Opportunistic infections were present in 57.5 percent of cases being in 38.4 percent the only pathological process, whereas in 19.1 percent they coexisted with HIV-dependent pathology or with neoplastic growth. Cytomegalovirus infection (22.7%), toxoplasmosis (16.3%), cryptococcosis (8.1%) and progressive multifocal leukoencephalopathy (9.3%) were the most common opportunistic infections of CNS. The remaining viral (herpetic encephalitis, tick-borne encephalitis and herpes zoster multifocal encephalitis), bacterial (lues, metastatic encephalitis connected with heart valvular changes) and fungal (candidiasis) infections were present only in single cases. It is worth mentioning 3 cases of brain aspergillosis and 5 cases of leptomeningeal tuberculosis. Great morphological variability in the most common opportunistic infections found in our material (cytomegaly, toxoplasmosis, cryptococcosis and PML) was the most striking phenomenon. Neuropathological abnormalities in cases of toxoplasmosis and cryptococcosis revealed remarkable dependence on clinical medication used. Cases of PML were characterized by strong variances of the type and intensity of demyelination, ranging from disseminated foci of various size to diffuse complete myelin loss in the white matter involving uni- or bilaterally cerebral or cerebellar hemispheres. The coexistence of opportunistic infections with HIV-dependent cerebral pathology or other types of opportunistic processes was a very characteristic feature. Concomitance of HIV-dependent pathology with viral opportunistic processes was common. The frequency of this concomitance and more severe HIV-dependent pathology in cases with other viral cerebral infections may suggest pathogenetic interaction of viral infections. Cerebral tuberculosis was less frequent as compared with other neuropathological collections, especially those from the United States. However, it seems worth mentioning that 3 of 5 cases occurred in the last year of observation.     

Measles and its complications in Hamburg from 1960 to 1973 (author's transl)

A study of measles was undertaken from the case histories of 3 093 children under 15 years of age, treated in the children's clinics of Hamburg between 1960 to 1973. 562 children were suffering from pneumonia (18,2%), 230 had otitis (7,4%) and 229 (7,4%) showed neural affections (143 cases with fits and 86 patients with encephalopathy or encephalitis), Various parameters were analysed: age, sex, seasonal distribution, fatality, age disposition to convulsions and measles encephalitis, "incubation period" of neural affections, sequelae. Permanent sequelae due to measles encephalitis were seen in 14% of the cases. A plea is made for an universal immunisation against measles.     

Varicella zoster virus vaccine--a review

The available published data on the efficacy and safety of a live attenuated varicella vaccine is presented. The data indicate that immunosuppressed leukemic children at high risk for severe varicella can be vaccinated resulting in complete or partial immunity in most children. Vaccination of immunosuppressed children is often associated with fever and rash. There seems to be a decreased risk of herpes zoster in vaccinated leukemic children when compared with a group of naturally infected leukemic children. In order to diminish the risk of varicella zoster virus (VZV) transmission to these high-risk persons family members of these, if susceptible to varicella infection, should be immunized. Although vaccination of healthy children is highly effective and associated with a low frequency of adverse events, vaccination in this group may be questioned due to the benign course of varicella. Due to the more severe VZV-infection seen among non-immune healthy adults, it seems reasonable to offer vaccination to this group. It will, however, require extensive serological testing to identify seronegative individuals. From a theoretical point of view a booster-vaccination to the elderly population, resulting in detectable cell-mediated immunity to VZV, should reduce the risk of herpes zoster. Large placebo-controlled studies are needed to confirm if such an immunization can prevent herpes zoster in this age group.     

Bacterial meningitis in southwestern Alaska

Between July 1, 1971, and June 30, 1974, thirty-nine cases of bacterial meningitis were diagnosed at the Alaska Native Health Service Hospital at Bethel, Alaska. Thirty-two (82%) occurred in infants less than one year of age. Haemophilus influenzae (H. influenzae) was the predominant causative agent, and was isolated from 23 (72%) of the 32 patients under one year of age. The annual incidence of H. influenzae meningitis in the Bethel area was 63/100,000, and the annual incidence of H. influenzae meningitis in children less than five years of age was 474/100,000 cases.     

Herpes varicella zoster encephalitis in immunocompromised patients

The authors describe specific MRI features that suggest the diagnosis of varicella zoster encephalitis. MRI initially revealed discrete, subcortical, nonenhancing lesions that coalesced and developed enhancement. Gray matter involvement was seen later. Autopsy revealed spherical lesions of demyelination and hemorrhagic cavitation confirmed as varicella zoster encephalitis. Characteristic MR features may suggest the diagnosis of varicella zoster encephalitis, enabling definitive diagnostic testing and early institution of antiviral treatment.     

Meningococcal disease in childhood--a regional study in Ireland

A retrospective study of microbiology laboratory records of culture-confirmed cases of meningococcal disease in children under 14 years of age, admitted to four Dublin hospitals, was conducted for the period 1981-1991 inclusive. The study aimed to describe the epidemiology of meningococcal disease in childhood and to assess the potential of meningococcal group A and C vaccine in preventing disease. There were 406 cases of meningococcal disease of which 319 (78.6%) were in children under 5 years of age. The meningitis to septicaemia ratio was almost 4:1 (320 vs. 86 cases). Of the 406 cases, 216 (53.2%) cases occurred during the period November to March. The age-specific annual incidence rates for the Eastern Health Board region served was 64.2 per 100,000 under 1 year of age and 24.6 per 100,000 under 5 years of age. A relative increase in disease caused by meningococcal serogroup C was observed during the period of the study. Only 15% all cases could have been prevented by a policy of universal meningococcal group A and C immunisation at 2 years of age. Such a policy, therefore, is not recommended. A vaccine for preventing disease caused by meningococcal group B is urgently required.     

The Inventory of Functional Status-Dialysis: development and testing

Pet and wildlife populations are a potential source of various public health problems, and injuries and complications due to animal bites and scratches are the most obvious. As no population based data on the frequency of animal bites were available at a national level in Switzerland, a study was conducted by the Swiss Sentinel Surveillance Network. The objectives of this study were to estimate the incidence of medical consultations due to bite and scratch injuries in humans caused by vertebrate animals, to identify possible risk factors, and to assess bite management habits in primary health care. An annual bite and scratch incidence rate of 325 per 100,000 population was estimated. Consultations peaked during the summer months and geographical differences in the reported incidence were observed. Dogs accounted for more than 60% and cats for about 25% of all cases reported. Animal bites and scratches were frequent in persons under 20 years of age. In most ages, the incidence was higher among women than among men, but not in children under the age of ten years. The incidence of cat bites was especially high in adult women. Bites to the head and neck were most frequent in infants and young children and accounted for approximately one third of the reported cases in this age group. Patients sought medical care principally for primary wound care (52.0%) and for vaccination advice (29.6%). Rabies postexposure prophylaxis was initiated in 1.1% of patients. Wound infection was reported in 10.9% of cases, with cat bites/scratches being more often infected than injuries due to dogs. Hospitalization was reported in 0.3 % of patients. Data from the emergency department of two district hospitals showed that head and neck injuries were more frequent in out-patients and a higher proportion of persons presented with wound infections (14.1%). The hospitalization rate for emergency department visits was 4.7%. Animal bites and scratches are common events in Switzerland. They represent a public health issue of growing importance due to the steadily increasing pet population. A practice based sentinel surveillance system may be an appropriate tool to monitor national trends in animal bites and scratches.     

The incidence of pediatric rheumatic diseases: results from the Canadian Pediatric Rheumatology Association Disease Registry

OBJECTIVE: To determine the incidence of rheumatic diseases in children, and the frequency of musculoskeletal disorders seen by pediatric rheumatology specialists in Canada. METHODS: Applying standardized disease definitions and disease codes modified from ICD-9, members of the Canadian Pediatric Rheumatology Association from 13 centers in all 10 provinces of Canada registered all new patients seen between May 1, 1991 and April 30, 1993. Patient data included age, sex, ethnicity, date of birth, date of disease onset, date of diagnosis, and diagnostic codes (more than one diagnosis could be entered). To minimize the bias of right censoring, only data from patients with disease onset between May 1, 1991 and October 31, 1992 were used to estimate disease incidence. RESULTS: 3362 records totalling 3683 diagnoses (92 separate diagnoses) were registered. Median referral rate per year to a pediatric rheumatology center was 26 per 100,000 children at risk. The frequency of diseases seen was 23.3% for all forms of chronic arthritis, 6.5% for connective tissue diseases, and 6.1% for all forms of vasculitis. The minimum incidence rates per 100,000 children at risk per year calculated from the whole registry were: all forms of chronic arthritis 4.08 (95% CI: 3.62, 4.60), systemic lupus erythematosus 0.28 (0.18, 0.45), and dermatomyositis 0.15 (0.09, 0.29). Substantially higher figures were obtained if the figures were calculated excluding the 2 provinces (Alberta and Quebec) that had disproportionately low referral rates. CONCLUSION: Pediatric rheumatologists see children with a wide variety of diseases. It is important that pediatric rheumatology training reflects this and does not focus exclusively on the classical inflammatory arthropathies. The minimum incidence data show there are substantial numbers of children developing potentially lifelong chronic rheumatic diseases each year in Canada. These data should be helpful in planning the delivery of pediatric rheumatology services not only in Canada, but also in other developed countries.     

Effect of nutrition improvement project on morbidity from infectious diseases in preschool children in Vietnam: comparison with control commune

OBJECTIVE: To evaluate the effect of a nutrition improvement project based on home garden production and nutrition education on morbidity from acute respiratory infection and diarrhoeal disease in preschool children. DESIGN: The morbidity survey comprised five data collections undertaken by trained interviewers to ascertain the incidence and severity of respiratory infections and the incidence of diarrhoeal disease in children in two communes. SETTING: A project commune and a control commune in Vietnam. SUBJECTS: Preschool children to 6 years of age living in the project commune Khai Xuan (average 469 children) and the control commune Ching Cong (average 251 children). MAIN OUTCOME MEASURES: Differences between the two communes over time in the incidence and severity of respiratory infections and the incidence of diarrhoeal disease. RESULTS: In Khai Xuan there was a significant reduction (P < 0.0001) in the incidence of respiratory infections (from 49.5% to 11.2%) and diarrhoeal infections (18.3% to 5.1%); the incidence of pneumonia and severe pneumonia was also significantly reduced (P < 0.0001). In Ching Cong there was no significant change in the incidence and severity of respiratory disease nor in the incidence of diarrhoeal disease. CONCLUSIONS: These findings emphasise the successful health outcome of a nutrition project based on household food production and nutrition education and the value of evaluating nutrition projects by reference to measurable health outcomes.     

Sarcoidosis in children. Epidemiology in Danes, clinical features, diagnosis, treatment and prognosis

This paper reviews current knowledge of childhood sarcoidosis with regard to the epidemiology in Danes, clinical presentation, diagnostic procedures, treatment and prognosis. Sarcoidosis is a granulomatous disease of unknown aetiology, with multiorgan involvement. The diagnosis is confirmed by the demonstration of epitheloid cell granulomas in tissue biopsy specimens. During the period 1980-92, three cases of childhood sarcoidosis were recorded in Copenhagen County, which has a total population of 610,000. The approximate incidence of clinically recognized sarcoidosis in Danish children younger than 15 y of age was 0.22-0.27/100,000 children per year, corresponding to approximately three new cases in Denmark each year. The true incidence is unknown, since the disease is often asymptomatic and resolves without a clinical diagnosis being made. In children younger than 5 y of age, the disease is characterized by involvement of skin, eyes and joints, whereas in older children involvement of lungs, lymph nodes and eyes predominate. The mainstay of treatment consists of oral corticosteroids. The risk/benefit ratio of using long-term corticosteroids needs to be evaluated in each individual patient. Some patients may benefit from additional therapy with methotrexate. The long-term prognosis is not well established, but it seems to be poorer in children younger than 5 y. Older children appear to have as favourable a prognosis as young adults.     

Kingella kingae: an emerging cause of invasive infections in young children

Kingella kingae, a fastidious hemolytic gram-negative bacillus once considered to be an exceptional cause of disease, has emerged in recent years as an important invasive pathogen in children. When synovial fluid and other exudates were inoculated into blood culture bottles, enhanced recovery of the organism was observed, and an annual incidence of invasive K. kingae infections of 27.4 per 100,000 children younger than age 24 months was demonstrated in southern Israel. Skeletal infections are the most common clinical presentation of K. kingae, and studies conducted in that region have shown that this organism is the most common etiology of septic arthritis in children below the age of 24 months. Other invasive diseases caused by K. kingae include bacteremia, endocarditis, and infections involving the lower respiratory tract, the eyes, or the central nervous system. Recent studies have demonstrated that K. kingae is part of the normal oropharyngeal flora of young children. Clinical data suggest that the organism may gain access to the bloodstream in the course of an upper respiratory infection or stomatitis. The organism is susceptible to a wide range of antimicrobial drugs, and with the exception of some cases of endocarditis, K. kingae infections in children usually run a benign clinical course.     

Incidence and prevalence of juvenile chronic arthritis in East Berlin 1980-88

OBJECTIVE: To estimate the incidence and prevalence rates of juvenile chronic arthritis (JCA). METHODS: The study population was children under 16 years of age living in the East Berlin area (part of the former German Democratic Republic). By admission order that was effective up to 1990, all children with symptoms of a rheumatic disease living in the East Berlin area had to be referred to the 2nd Children's Hospital at Berlin-Buch. This specific condition allowed us to ascertain cases from the clinical records and to calculate population rates. Based upon this data, the results of surveys with different methods of case ascertainment are compared. RESULTS: An incidence rate of 3.5 per 100,000 and a prevalence rate of 2.0 per 10,000 children were calculated. The frequency of JCA is higher for girls, with an incidence of 4.3 per 100,000 and a prevalence of 2.3 per 10,000. The figures for boys are 2.7 per 100,000 and 1.7 per 10,000, respectively. CONCLUSION: Because of the specific prerequisites, the population rates of prevalence and incidence that were based on clinical records can be regarded as valid in this study. Deviant results of other surveys can be explained by differences in the study design or in the diagnostic procedures used.     

Paracoccidioidomycosis: an epidemic in the Republic of Paraguay, the center of South America

The investigation done on the frequency or incidence of Paracoccidioidomycosis in the Republic of Paraguay, with the cases appeared and registered in the Institute of Pathology of Asuncion, presents an incidence rate of 0.46 per 100,000 in the total population; 0.52 per 100,000 in the population at risk. Considering the exposed masculine population the rate is 1.03 per 100,000 and for the feminine 0.02 per 100,000. The age group most affected is within the 50-54 year range with 3.54 per 100,000, the highest rate of all the groups studied. These are the incidence in a strongly exposed population which is controlled and well known. The period of 10 years (1960/69) which has been chosen for this investigation, shows a frequency of the mixed type (lymphatic-visceral or lymphoma-type) which reaches 25% of the total, and a low frequency for the pulmonary form which reaches a mere 12.5%. The mucocutaneous lesion with the involvement of the regional lymph nodes is the dominating form. Considering three consecutive 5 year periods between 1960 to 1974, no cases with proved pulmonary involvement were found until 1964; from 1965 to 1969 the percentage of pulmonary lesions in all the cases considered was 23.0% and from 1970 to 1974 reached to 38.4%. However, mucocutaneous and the lymphatic-visceral or mixed forms do not show significant variations. The rats are small and represent the incidence of this mycosis. It is suggested that a failure of the immunologic system would be found in those affected by the disease and there would be a strong resistence in the majority of the population exposed or within the endemic area of the infection.     

Prevention and control of hepatitis B virus infection in Singapore

Hepatitis B virus (HBV) accounted for 24% to 54% of the reported acute viral hepatitis cases in Singapore from 1982 to 1996. The prevalence of HBV infection, as indicated by the presence of markers of HBV, increased from 9.3% in children below 5 years of age to 54.6% in adults above 55 years. The overall hepatitis B surface antigen (HBsAg) prevalence was 5.7% for males and 3.4% for females, with the highest rate among the Chinese. About 39% of the HBsAg carriers were hepatitis B 'e' antigen positive. The main mode of transmission during the first year of life was perinatal, with 43% of the babies born to HBsAg-positive mothers developing the carrier state. Horizontal transmission within the infected household was significantly associated with sharing of personal and household articles. Based on the findings of seroprevalence surveys in various population groups and clinical trials on the safety, immunogenicity and efficacy of various doses and schedules with the plasma-based and yeast-derived hepatitis B vaccines in newborn babies, a national childhood hepatitis B vaccination programme was formulated and implemented in phases, starting with babies born to carrier mothers on 1 October 1985 and finally extending to all newborns on 1 September 1987. The hepatitis B prevention and control programme has been successful. During the period 1994 to 1996, more than 90% of children completed the full schedule of immunisation by below one year of age, and 85% had evidence of vaccination at school entry at age six. Follow-up of 2 cohorts of vaccinated children showed that perinatal transmission has been reduced by 80% to 100%. Horizontal transmission has also declined through other public health measures. The efficacy of the hepatitis B vaccine and the adequacy of reduced doses in the long-term protection of chronic carrier state have been shown in children and adults. The incidence of acute hepatitis B has declined from 10.4 per 100,000 in 1985 to 4.8 per 100,000 in 1996. There is a noticeable reduction in HBsAg prevalence in selected population (school children, national servicemen and antenatal women). The age-standardised incidence rate of primary liver cancer among males had also dropped from 27.8 per 100,000 per year during 1978 to 1982 to 19.0 per 100,000 per year during 1988 to 1992.