Decreased survival of HTLV-I carriers in leprosy patients from the Democratic Republic of the Congo: a historical prospective study.

In this historical prospective study using sera stored for 22 years, we investigated the effect of HTLV-I infection on survival in a population of leprosy patients in the Democratic Republic of the Congo (formerly Zaire). We also determined the distribution of HTLV-I by subpopulation, age, and gender. Stored sera taken from a population of leprosy patients and controls in 1969 were tested for HTLV-I. Follow-up survival data on these patients were obtained in 1991. The sera collected in 1969 from 520 individuals was used to determine the prevalence of HTLV-I. Included in this number were 328 patients resident in the sanatorium. Survival and other data were available for 327 of these. A multivariate survival analysis using a logistic regression model was performed to evaluate the influence of HTLV-I status, age, type of leprosy, gender, duration of hospitalization, and ethnic group on survival. The overall prevalence of HTLV-I among the 520 individuals in the prevalence study was 34%, with 37.4% in the leprosy group and 25.2% in the control group (p < 0.01). Multivariate analysis using logistic regression showed that females of the Mongo and Ngombe ethnic group taken together were significantly more likely to be infected than the other groups (OR = 3.67, 95% CI: 2.14 to 6.30). A comparison of the death rates directly standardized for age and sex showed that the rate was significantly higher for HTLV-I positive (5.5/100 person-years of observation) compared with HTLV-I negative (3.6/100 person-years of observation). A survival analysis using the Cox model showed a risk ratio of 1.4 (CI: 1.04 to 1.89) for those infected with HTLV-I. An increase in the death rate was associated with HTLV-I infection in leprosy inpatients. The decreased survival associated with HTLV-I infection may result from an increased susceptibility to a variety of diseases.

PIP: Preservation of stored sera collected in 1969 from leprosy patients at a sanatorium in the Democratic Republic of the Congo's Equator Province enabled an analysis of the survival of carriers of human T-cell lymphotropic virus type 1 (HTLV-1). The HTLV-1 prevalence in the sera collected from 377 leprosy patients and 143 controls in 1969 was 34% (37.4% and 25.2%, respectively). Multivariate survival analysis was performed to evaluate the impact of HTLV-1 status, age, type of leprosy, gender, duration of hospitalization, and ethnic group on the survival of leprosy patients. Members of the Mongo ethnic group were more likely than those of the Ngombe ethnic group to be infected. After adjustment for age and sex, mortality was significantly higher among HTLV-1-positive cases (5.5 per 100 person-years of observation) than HTLV-1-negative persons (3.6 per 100 person-years of observation). A survival analysis using the Cox model revealed a mortality risk ratio of 1.4 (95% confidence interval, 1.04-1.89) for HTLV-1-positive individuals. The reduced survival observed in HTLV-1-infected leprosy patients presumably resulted from concomitant increased susceptibility to other diseases.

Eliminating leprosy as a public health problem--is the optimism justified?

Systematic use of multidrug therapy has proved to be so effective that leprosy can be eliminated as a public health problem by the end of the century. However, because of the long incubation period of this disease, together with the time-lag in case detection, the factors involved in achieving and sustaining its elimination have to be very carefully defined.

Serological and nucleic acid analyses for HIV and HTLV infection on archival human plasma samples from Zaire.

In order to better understand the genomic diversity and molecular phylogeny of the human retroviruses, the plasmas from 250 Zairean patients collected in 1969 were tested for antibodies to human T-cell lymphoma and human immunodeficiency viruses (HTLV or HIV) using ELISA and confirmatory Western blots and for viral nucleic acids by reverse transcriptase-directed PCR (RT-PCR). Interestingly, none of the patients was confirmed positive for HIV, even though this region is now endemic for HIV-1. However, 74 (30%) and 3 (1%) of the samples were positive for antibodies to HTLV-I and II, respectively. Forty-four of 74 (59%) Western blot-positive Zairean samples were RT-PCR positive for HTLV-I, while 1 of 3 (33%) of HTLV-II-seropositive samples was RT-PCR positive. On the contrary, none of the Western blot-negative or indeterminate samples were RT-PCR positive for either HTLV-I or HTLV-II. We have cloned and sequenced 140 bp of the pol gene flanked by SK110/SK111 from 8 HTLV-I- and 1 HTLV-II-positive archival samples from Zaire. The HTLV-I isolates from Zaire cluster together as a phylogenetic group, diverging from the prototype Japanese HTLV-I (ATK) by a range of 1.4 to 3.6%. Their close homology to some African STLV-I isolates suggests relatively recent interspecies transmission. The Zairean HTLV-II isolate is closely grouped with the HTLV-II substrain of isolates found in Paleo-Amerindians of the New World, making it unlikely that it represents an endemic African strain.

Registries of congenital anomalies: EUROCAT.

Congenital anomalies are one of the potential adverse effects of the environment on reproductive health. Registries of congenital anomalies are useful to detect abnormal frequencies, clusters, and trends. Such registries should meet a number of conditions, including an appropriate population denominator, an efficient system for collecting information, standardized diagnostic procedures, postmortem examinations of still-births, and linkage of records. The EUROCAT (European Registration of Congenital Anomalies and Twins) program is a Concerted Action of the Commission of the European Communities initiated in 1979. One of its objectives is the surveillance of congenital anomalies as related to environmental hazards. This surveillance system covers at present 350,000 births per year in 15 countries. A number of problems encountered in the development of EUROCAT and in the course of ongoing activities are reviewed: populations coverage, classification of malformations, coding, definition and coverage of late fetal death, registration of induced abortion, validation of diagnostic information, registration of late diagnosed cases, and maintenance of motivation in data collection. The issue of confidentiality and the need for strict safeguards for the protection of individual privacy are emphasized.

The epidemiology of tracheo-oesophageal fistula and oesophageal atresia in Europe. EUROCAT Working Group.

The total prevalence rate of tracheo-oesophageal fistula and oesophageal atresia in 15 EUROCAT registries covering 1,546,889 births during 1980-8 was 2.86 per 10,000. There was a decreasing prevalence rate over time (3.5 per 10,000 in 1980-2, 2.7 in 1983-5, 2.5 in 1986-8). Ten per cent of cases were associated with chromosomal anomalies and of the remaining cases, half were multiply malformed. Sixty two per cent of cases were males. There was a significantly increased risk for mothers of less than 20 years of age (odds ratio compared with mothers of 25-29 = 1.82, 95% confidence interval 1.23 to 2.67). There were no apparent epidemiological differences between isolated and multiply malformed cases in secular trend, sex ratio, or maternal age. Both isolated and multiply malformed cases tended to be premature and small for gestational age. There was variation between centres in survival of affected liveborn children up to 1 year of age.

Accident and disaster epidemiology.

Natural disasters such as floods, earthquakes, and cyclones are responsible each year for a large number of deaths and injuries. Over recent years, the emphasis in disaster management has shifted from post-disaster improvisation to pre-disaster planning. There is a strong feeling that one should be able to prevent or mitigate the human consequences through improved preparedness. The decade 1990-99 has been proclaimed by the United Nations the International Decade for Natural Disaster Reduction (IDNDR). Epidemiology is proving an essential tool to study the health effects of disasters and to suggest appropriate control measures at each of the phases of the disaster process, from prevention to long-term rehabilitation. Case-studies have shown that rescue by the disaster-struck community is the most effective way to reduce the death toll due to earthquakes. Disaster preparedness should be part and parcel of primary health care in disaster-prone areas. Appropriate information to evaluate needs should be preferred to precipitate relief. Epidemiological surveillance should replace indiscriminate vaccination. In the long term, disaster preparedness can provide a stimulus for setting up more efficient health services.