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Biomedical subjects

K M De Cock

Publications and source records attributed to K M De Cock.

At least 19 recordsLinked to original sources
PubMed1999

Risk factors for pulmonary mycobacterial disease in South African gold miners. A case-control study.

Pulmonary mycobacterial disease is common in miners. Risk factors for nontuberculous pulmonary mycobacterial (NTM) disease and tuberculosis (TB) in gold miners were identified in a retrospective case-control study that included 206 NTM patients and 381 TB patients of known human immunodeficiency virus (HIV) status diagnosed between 1993 and 1996. A total of 180 HIV-tested trauma/surgical inpatients were selected as control patients. Both HIV infection (odds ratio [OR] 3.6 for NTM and 4.5 for TB patients) and higher grades of silicosis (OR 5.0 for NTM and 4.9 for TB patients) were significantly more common in NTM and TB patients than in control patients. HIV prevalence rose in the control and both case groups during the study period. The overall HIV prevalence was 13.1% in NTM patients, 14.2% in TB patients, and 5.6% in control patients. Previous TB (OR 9.6), premorbid focal radiological scarring (OR 7.4) and a dusty job at diagnosis (OR 2.4) were additional significant risk factors for NTM disease. These findings suggest that the historically high incidence of NTM disease in miners is largely attributable to chronic chest disease from silica dust inhalation and prior TB. HIV infection has recently become an additional risk factor for mycobacterial disease in miners and is likely to become increasingly important as the HIV epidemic progresses.

Adult↗
PubMed1998

Disease progression and survival in HIV-1-infected Africans in London.

OBJECTIVE: To examine differences in progression to AIDS and death between HIV-1-positive Africans (most infected in sub-Saharan Africa and therefore with non-B subtypes) and HIV-1-positive non-Africans in London. DESIGN: Retrospective cohort study of 2048 HIV-1-positive individuals. SETTING: HIV-1-infected individuals attending 11 of the largest HIV/AIDS units in London. PATIENTS: Subjects were 1056 Africans and 992 non-Africans seen between 1982-1995. RESULTS: There were no differences in crude survival from presentation to death between Africans and non-Africans (median 82 and 78 months, respectively; P = 0.22). Africans progressed more rapidly to AIDS [hazard ratio (HR), 1.21; 95% confidence interval (CI), 1.02-1.45] but after adjustment for age, sex, Centers for Disease Control and Prevention category B symptoms and CD4+ lymphocyte count at presentation, year of HIV diagnosis and hospital attended, this difference was no longer significant (adjusted HR, 1.15; 95% CI, 0.93-1.43). Africans with AIDS had a reduced risk of death compared with non-Africans (HR, 0.78; 95% CI, 0.63-0.96) but not after adjustment for age, CD4+ lymphocyte count at AIDS, initial AIDS-defining conditions (ADC) and hospital attended (HR, 0.98; 95% CI, 0.76-1.27). Tuberculosis as the first ADC was associated with a 64% reduction in the risk of death. CD4+ lymphocyte decline was not significantly different between Africans and non-Africans (P = 0.18). CONCLUSIONS: Differences in progression to AIDS and death and CD4+ lymphocyte decline between HIV-1-infected Africans and non-Africans in London could not be attributed to ethnicity or different viral subtypes. Age and the clinical and immunological stage at presentation, or AIDS, were the major determinants of outcome. Compared with other diagnoses, tuberculosis as the initial ADC was associated with increased survival. Lack of access to health care and exposure to environmental pathogens are the most likely causes of reduced survival with AIDS in Africa, rather than inherently different rates of progression of immune deficiency due to racial differences or viral subtypes.

Acquired Immunodeficiency Syndrome↗
PubMed1998

Disease progression and survival following specific AIDS-defining conditions: a retrospective cohort study of 2048 HIV-infected persons in London.

OBJECTIVE: To assess the impact of specific AIDS-defining conditions on survival in HIV-infected persons, with emphasis on the effect of tuberculosis. METHODS: A retrospective cohort analysis of HIV-infected Africans and non-Africans attending 11 specialist HIV/AIDS units in London enrolled for a comparison of the natural history of HIV/AIDS in different ethnic groups. RESULTS: A total of 2048 patients were studied of whom 627 (31%) developed 1306 different AIDS indicator diseases. Pneumocystis carinii pneumonia accounted for 159 (25%) of initial AIDS episodes and tuberculosis for 103 (16%). In patients with HIV disease, tuberculosis had the lowest risk [relative risk (RR), 1.11; 95% confidence interval (CI), 0.75-1.63], and high-grade lymphoma had the highest risk (RR, 20.56; 95% CI, 2.70-156.54) for death. For patients with a prior AIDS-defining illness, the development of subsequent AIDS indicator diseases such as Pneumocystis carinii pneumonia (RR, 1.18; 95% CI, 0.77-1.83) and tuberculosis (RR, 1.36; 95% CI, 0.76-2.47) had the best survival, and non-Hodgkin's lymphoma had the worst survival (RR, 9.67; 95% CI, 1.26-74.33). Patients with tuberculosis had a lower incidence of subsequent AIDS-defining conditions than persons with other initial AIDS diagnoses (rate ratio, 0.47; 95% CI, 0.37-0.59). CONCLUSIONS: Considerable variation exists in the relative risk of death following different AIDS-defining conditions. The development of any subsequent AIDS-defining condition is associated with an increased risk of death that differs between diseases, and this risk should be considered when evaluating the impact of specific conditions. Like other AIDS-defining conditions, incident tuberculosis was associated with adverse outcome compared with the absence of an AIDS-defining event, but we found no evidence of major acceleration of HIV disease attributable to tuberculosis.

AIDS-Related Opportunistic Infections↗
PubMed1998

The Côte d'Ivoire national HIV counseling and testing program for tuberculosis patients: implementation and analysis of epidemiologic data.

OBJECTIVES: To describe the implementation of a free, voluntary and confidential HIV counseling and testing program for patients with newly diagnosed tuberculosis at the eight large outpatient tuberculosis centers in Côte d'Ivoire, and to present epidemiologic findings on participating patients. DESIGN: HIV counseling and testing program with ongoing HIV serosurveillance. METHODS: HIV counseling and testing services were established at the two tuberculosis centers in Abidjan in 1989 and were extended to six centers in the Côte d'Ivoire interior in the first half of 1994. Characteristics of counseled patients, acceptance rates of HIV testing, and HIV serologic results were analyzed for all eight centers from 1994 to 1996. Temporal trends in HIV seropositivity rates were examined for the two centers of Abidjan from 1989 to 1996. RESULTS: From July 1994 through December 1996, 17 946 (91.8%) out of 19 594 patients who were counseled at the eight centers in Côte d'Ivoire consented to HIV testing, of whom 7749 (43.2%) were HIV-seropositive. The highest rates of 47.0 and 45.6% were found in the two centers in Abidjan, with rates ranging from 32.9 to 42.4% in the six centers in the interior. HIV-seropositive tuberculosis patients from each of the 50 districts in Côte d'Ivoire were identified. In Abidjan, the HIV seropositivity rate remained relatively stable among men (46.7% in 1989, 48.5% in 1991, 43.6% in 1996), but rose sharply among women from 32.7% in 1989 to 50.1% in 1996. CONCLUSIONS: The high HIV seropositivity rates among tuberculosis patients in all geographic regions of Côte d'Ivoire indicate that the HIV epidemic has now spread throughout the country. However, the successful implementation of an extensive HIV counseling and testing program for more than 37000 tuberculosis patients to date demonstrates the commitment of the Côte d'Ivoire Ministry of Health to integrating HIV/AIDS prevention activities with tuberculosis control efforts. When logistically and economically feasible, the extension of HIV-related social and clinical services to HIV-seropositive tuberculosis patients should be considered by other national tuberculosis control programs in Africa.

AIDS Serodiagnosis↗
PubMed1998

The growing challenge of HIV/AIDS in developing countries.

The burden of HIV infection and disease continues to increase in many developing countries. An emerging theme is of an HIV pandemic composed of mini-epidemics, each with its own characteristics in terms of the trends in HIV prevalence, those affected, and the HIV-related opportunistic diseases observed. A number of explanations for the observed differences in the spread of HIV infection have been proposed but since the factors concerned, such as sexual behaviour and the prevalence of other sexually transmitted diseases, are closely interrelated, it is difficult to tease out which are the most important. Among HIV-related opportunistic diseases, tuberculosis stands out as the most important cause of morbidity and mortality in most developing countries, but the relative prevalence of other diseases shows considerable regional variation. Thus, there is a need for local approaches to the global problem of managing HIV disease. The most pressing public health challenges are to use existing knowledge of strategies to reduce HIV transmission, and to apply them in ways appropriate to the local situation, and to develop, evaluate and implement interventions to prolong healthy life in those already infected.

AIDS-Related Opportunistic Infections↗
PubMed1998

Spectrum of disease among HIV-infected adults hospitalised in a respiratory medicine unit in Abidjan, Côte d'Ivoire.

SETTING: Respiratory medicine wards of the University Teaching Hospital, Abidjan, Côte d'Ivoire. OBJECTIVES: To describe the spectrum of opportunistic infection among human immunodeficiency virus (HIV) infected adults hospitalised in the respiratory medicine unit in Abidjan, and the level of immunosuppression at which these diseases occur. DESIGN: Cross-sectional study. RESULTS: Overall, 75% of patients were HIV-positive: among these patients, the most frequent diagnosis was tuberculosis, in 61%, followed by bacterial pneumonia (15%), Gram-negative septicaemia (particularly non-typhoid Salmonella) (9%) and empyema (5%). Atypical pneumonias appeared to be rare. Most HIV-positive patients had CD4 counts indicative of advanced immunosuppression: 36% had CD4 counts below 100 x 10(6)/l, 19% between 100 and 199 x 10(6)/l, 29% between 200 and 499 x 10(6)/l, and 16% above 500 x 10(6)/l. Overall in-hospital mortality was 27% for HIV-positive patients and 22% for HIV-negative patients (P = 0.5). In a multivariate analysis, the strongest independent risk factors for death were cachexia (odds ratio [OR] 7.4, 95% confidence interval [CI] 2.1-26.3), male sex (OR 4.5, 95% CI 1.2-17.4) and age over 40 (OR 4.1, 95% CI 1.0-17.2). CONCLUSIONS: Tuberculosis and bacterial infections are the major causes of respiratory morbidity in immunosuppressed HIV-infected adults in this population. Efforts to improve the management of HIV-related disease need to focus on prevention and treatment of these infections.

AIDS-Related Opportunistic Infections↗
PubMed1997

HIV and AIDS, other sexually transmitted diseases, and tuberculosis in ethnic minorities in United Kingdom: is surveillance serving its purpose?

Experience of disease differs across ethnic groups, and ethnicity is a relevant personal characteristic for descriptive epidemiology. Information about ethnicity and country of birth is omitted from the routine notification of many diseases. HIV infection and AIDS, other sexually transmitted diseases, and tuberculosis have different incidence rates in different ethnic groups in the United Kingdom. Omission of ethnic data from surveillance activities allows such differences in incidence to go undetected and unaddressed. Surveillance data that included ethnic details could guide interventions to reduce inequalities in health between different subpopulations.

Acquired Immunodeficiency Syndrome↗
PubMed1997

Late postnatal mother-to-child transmission of HIV-1 in Abidjan, Côte d'Ivoire.

BACKGROUND: HIV-1 can be transmitted from an infected mother to her infant through breastfeeding, although the precise risk of transmission by this route is unknown. A long-term follow-up of children born to HIV-infected women in Abidjan, Côte d'Ivoire, has enabled us to estimate this risk. METHODS: Children born to 138 HIV-1-seropositive women, 132 HIV-2-seropositive women, 69 women seroreactive to both HIV-1 and HIV-2, and 274 HIV-seronegative women were enrolled at birth and followed up for as long as 48 months. All children were breastfed (median duration 20 months). Blood samples for either or both HIV PCR and HIV serology were obtained at 1, 2, and 3 months of age, and every 3 months thereafter. Early HIV infection was defined as a positive HIV-1 PCR result obtained in the first 6 months of life. Late postnatal transmission was diagnosed when a child had a negative PCR at 3 or 6 months of age, followed by either or both a positive HIV-1 PCR at 9 months or older, or persistently positive HIV-1 serology at 15 months or older. FINDINGS: 82 children born to HIV-1-seropositive mothers and 57 children born to mothers seropositive for both HIV-1 and HIV-2 had PCR results for samples taken within the first 6 months. By 6 months of age, 23 (28%; 95% CI 19-39) of the 82 children born to HIV-1-seropositive mothers and ten (18%; 95% CI 9-30) of the 57 children born to dually seropositive mothers were HIV-1 infected. Among children whose PCR results were negative at or before age 6 months, and who were followed up beyond 6 months, an additional four (9%) of the 45 children born to HIV-1-seropositive mothers and two (5%) of the 39 children born to dually seropositive mothers became HIV infected. The estimated rates of late postnatal transmission, with account taken of loss to follow-up and the observed pattern of weaning, were 12% (95% CI 3-23) and 6% (0-14), respectively. One of the five children whose mothers seroconverted from HIV-negative to HIV-1, and one of seven children whose mothers seroconverted from HIV-2 to dual reactivity, became HIV-1 positive. No case of late postnatal transmission occurred in children born to HIV-2-positive or persistently HIV-negative mothers. INTERPRETATION: Breastfed children born to mothers seropositive for HIV-1 alone or seropositive for HIV-1 and HIV-2 in Abidjan are at substantial risk of late postnatal transmission. Early cessation of breastfeeding at 6 months of age should be assessed as a possible intervention to reduce postnatal transmission of HIV.

Breast Feeding↗
PubMed1997

Profound immunosuppression across the spectrum of opportunistic disease among hospitalized HIV-infected adults in Abidjan, Côte d'Ivoire.

OBJECTIVES: To describe the spectrum of opportunistic disease in HIV-infected patients admitted to hospital in Abidjan, Côte d'Ivoire, and to describe the level of immunosuppression at which these diseases occur. DESIGN: Cross-sectional study. SETTING: In-patient wards of the University Hospital Infectious Diseases Unit. PATIENTS: A total of 250 adult patients recruited by systematic sampling at the point of hospital admission. MAIN MEASURES: HIV status; CD4 count; diagnoses, confirmed by microbiological/radiological investigations whenever possible; and outcome of hospitalization (death or discharge). RESULTS: Overall, 79% patients were HIV-positive. The most frequent diagnoses in HIV-positive patients were septicaemia (20%, with non-typhoid salmonellae, Escherichia coli and Streptococcus pneumoniae the most common organisms), HIV wasting (16%), meningitis (14%), tuberculosis (TB; 13%), isosporiasis (10%), cerebral toxoplasmosis (7%) and bacterial enteritis (7%). Most HIV-positive patients had evidence of severe immunosuppression: 39% had CD4 counts < 50 x 10(6)/l, 17% had 50-99 x 10(6)/l, and 20% had 100-199 x 10(6)/l. In-hospital mortality among HIV-positive patients was 38% compared with 27% among HIV-negative patients [age-adjusted odds ratio (OR), 1.5; 95% confidence interval (CI), 0.7-2.9]. Among HIV-positive patients, the highest case-fatality rates were among patients with meningitis, toxoplasmosis and TB: in a multivariate analysis the strongest independent risk factors for death were an abnormal level of consciousness (OR, 9.3; 95% CI, 3.5-24.6), a haemoglobin concentration below 8 g/dl (OR, 4.2; 95% CI, 1.4-12.8) and age > 40 years (OR, 3.9; 95% CI, 1.5-10.2). CONCLUSIONS: Our data show that, as in industrialized countries, most HIV-infected individuals admitted to and dying in hospital in Abidjan are profoundly immunosuppressed. Potentially preventable infections are the main causes of in-hospital morbidity and mortality among HIV-infected persons in Abidjan, and the evaluation of appropriate primary prophylactic regimes is a priority.

AIDS-Related Opportunistic Infections↗
PubMed1997

Sexually transmitted diseases and human immunodeficiency virus infections in women attending an antenatal clinic in Abidjan, Côte d'Ivoire.

A cross-sectional survey was conducted among women attending an antenatal clinic in Abidjan to determine the prevalence of sexually transmitted diseases (STDs) and HIV infection, and to identify factors associated with the presence of gonococcal and/or chlamydial cervical infection. Among 546 women, 3.7% had a gonococcal infection and 5.5% had a chlamydial infection. The seroprevalence of syphilis and HIV was 1.1% and 16.2% respectively. Gonococcal and/or chlamydial cervical infection was associated with young age, the presence of endocervical mucopus and with more than 10 polymorphonuclear leucocytes per high power field in a vaginal smear. None of these associated factors had a large enough predictive value to allow its use as a diagnostic criterion. Sexually transmitted diseases are common in pregnant women in Abidjan. The development of rapid, inexpensive diagnostic tests for STD is a priority to improve the care of women attending antenatal clinics in the developing world.

Adolescent↗
PubMed1997

The neuropathology of HIV-infected African children in Abidjan, Côte d'Ivoire.

In an autopsy study of HIV-infected children in Abidjan, Côte d'Ivoire, the neuropathology of 76 HIV-1- and 2 HIV-2-positive children was compared with that of 77 frequency-matched HIV-negative children, in whom the systemic pathology was also known. Seventy of the 78 HIV-seropositive children were confirmed as HIV-infected, as determined by combined serology, IgA Western blots and clinicopathological criteria. The HIV-negative children showed a high background level (n = 49, 64%) of neuropathological abnormalities, including nonspecific inflammatory infiltrates, micromineralization, and bacterial and lymphocytic meningitis. In the HIV-positive children, HIV encephalitis was found in 4 (6%), cytomegalovirus in 2 (3%), toxoplasmosis in 3 (4%) and measles encephalitis in one (1%). Bacterial meningitis was equally common in both groups, but cerebral malaria was less common (n = 2, 3%) in HIV-positive than in HIV-negative children (n = 11, 14%). The low prevalence of HIV encephalitis may reflect comparatively early death in HIV infection in Africa as compared with our experience in Europe and the US.

Acquired Immunodeficiency Syndrome↗
PubMed1997

Natural history and spectrum of disease in adults with HIV/AIDS in Africa.

Progression from seroconversion to the development of AIDS in Africa may be shorter than in industrialized countries, but there are insufficient data to be certain. Although the data are not always directly comparable, survival after an AIDS diagnosis appears to be substantially shorter in African countries and this may be partly because of later diagnosis of AIDS in Africa, but may also be because of environmental factors such as increased exposure to pathogens of high virulence and lack of access to care. Tuberculosis and bacterial infections are the most important causes of morbidity and mortality among hospitalized patients. Bacteraemia is frequent, particularly due to non-typhoid salmonellae and S. pneumoniae. Cryptosporidia and I. belli are the most frequently isolated pathogens in patients with diarrhoea; non-typhoid salmonellae and Shigella species are also commonly isolated when stool cultures are performed. Cerebral toxoplasmosis, and meningitis due to Cryptococcus, tuberculosis and bacterial pathogens are the most frequent neurological infections and cognitive changes are frequently identified when specifically looked for. Infections with atypical mycobacteria and Pneumocystis carinii are rare, as is CMV retinitis. In women, HIV infection is associated with cervical human papillomavirus and with SIL, although there is currently no evidence for an association with invasive cervical cancer. Individuals infected with HIV-2 progress to AIDS and to death more slowly than those infected with HIV-1, but seem to experience the same spectrum of opportunistic disease when they reach the stage of advanced disease. The limited data available suggest that HIV-infected individuals in Africa develop opportunistic disease at broadly the same level of immunosuppression as do individuals in industrialized countries, but death occurs at a higher range of CD4 counts, although still in the range consistent with advanced disease. Data are still lacking concerning the aetiology of common clinical presentations of HIV disease and the relative frequencies of specific opportunistic diseases in different regions, particularly from southern Africa. Tuberculosis is the single most important HIV-related opportunistic infection in African countries, but diagnosis, particularly of extrapulmonary disease, remains difficult. The lack of laboratory facilities makes the diagnosis of bacterial infections difficult in many parts of the continent and, since this situation is unlikely to change in the near future, clinical algorithms for syndromic management need to be evaluated. More information is needed about gynaecological disease in HIV-infected women. The most important research questions concern the development and evaluation of cost-effective regimes for prophylaxis and treatment of opportunistic disease in order to prolong healthy life in HIV-infected individuals.

AIDS-Related Opportunistic Infections↗