Showing papers by "University of Zambia published in 1990"

Impact of HIV on tuberculosis in Zambia: a cross sectional study.

Abstract: OBJECTIVE--To examine the contribution of HIV infection to the apparently increasing incidence of tuberculosis in central Africa. DESIGN--Cross sectional study. SETTING--Outpatient clinic in teaching hospital, Lusaka, Zambia. PATIENTS--346 Adult patients with tuberculosis. RESULTS--Overall, 206 patients (60%; 95% confidence interval 54% to 65%) were positive for HIV--in one or both assays used. The peaks for both tuberculosis and HIV infection were among men aged 25-34 years and women aged 14-24 years. Of patients with confirmed pulmonary tuberculosis, 73/149 (49%; 41% to 57%) were positive for HIV; 67/83 (81%; 70% to 89%) patients with pleural disease and 16/19 (84%; 60% to 97%) patients with pericardial disease were positive. HIV positive patients with positive sputum culture were less likely to have had a positive sputum smear, and their chest x ray films less often showed classic upper zone disease or cavitation. Of 72 patients who fulfilled clinical criteria for AIDS, 17 were negative for HIV. CONCLUSIONS--The high prevalence of HIV in patients with tuberculosis suggests that an epidemic of reactivating tuberculosis is arising in those who are infected with HIV. The redirection of public health priorities towards tuberculosis would focus on a major treatable and preventable complication of the AIDS epidemic.

Syphilis intervention in pregnancy: Zambian demonstration project.

Abstract: Despite availability of simpler serologic tests for syphilis and near cure with penicillin, unacceptably high prevalence of infectious maternal syphilis exist in many developing countries, including Zambia. It is the foremost risk factor for mid-trimester abortions, stillbirths, prematurity and morbidity and mortality among infants born with congenital syphilis in Zambia. An intervention project was conducted in Lusaka aimed at demonstrating the effectiveness of new health education methods and prenatal screening for syphilis in reducing the adverse outcomes during pregnancy. During pre-intervention phase, approximately 150 consecutive pregnant women from each of the three study and the three control centres were recruited when they presented in labour at the University Teaching Hospital. The intervention phase lasted for one year at the three study centres during which new methods of health education were introduced to improve early attendances during pregnancy. Also, on-site syphilis screening was performed twice during pregnancy and seroreactive women, and in many cases their sexual partners, were treated by the existing prenatal clinic staff. During the post-intervention phase the steps of pre-intervention phase were repeated to evaluate the impact of intervention. Overall, 8.0% of women were confirmed seroreactive for syphilis; there was no difference between the study and the control centres (p greater than 0.05). Fifty seven percent (132/230) of syphilitic pregnancies ended with an adverse outcome, that is, abortion (RR 5.0), stillbirth (RR 3.6), prematurity (RR 2.6) and low birth weight (RR 7.8). The overall risk of adverse outcomes due to syphilis was 8.29 (95% confidence interval 6.53, 10.53). The new methods of health education were effective and the percentage of women who had their first prenatal visit under 16 weeks of gestation improved from 9.4 to 42.5. Although screening and treatment during intervention was suboptimal, the adverse outcomes attributable to syphilis were reduced to 28.3%; this is almost a two-third reduction when compared with 72.4% of adverse outcomes at control centres (p < less than 0.001). The intervention is culturally and politically acceptable in Zambia. The cost of each prenatal screening is US$0.60 and of averting each adverse outcome US$12. In countries with high rates of syphilis, there is an urgent need for STD control and Maternal and Child Health (MCH) programmes to pool their resources together to revitalise the prenatal care.

HIV-related enteropathy in Zambia: a clinical, microbiological, and histological study.

Abstract: To investigate the etiology of chronic diarrhea associated with human immunodeficiency virus (HIV) infection in Lusaka, we studied 63 HIV-positive patients and 36 seronegative controls clinically and endoscopically. Stools were studied for morphology and for opportunist infections. Fifty-five percent of patients seropositive for HIV who presented with a history of chronic diarrhea had parasites; the most common were Cryptosporidium (32%), Isospora belli (16%), and Strongyloides stercoralis (6%). As indicated by villous blunting and inflammation on duodenal histology, those with diarrhea and parasites showed the most severe damage. We could not implicate mycobacteria or bacterial overgrowth as causes for the enteropathy associated with HIV.

Epidemiology of human immunodeficiency virus in families in Lusaka Zambia.

Abstract: An investigation of members of households of patients with acquired immunodeficiency syndrome (AIDS) and AIDS-related complex (ARC) in Lusaka Zambia revealed a high rate of human immunodeficiency virus (HIV) infection in marital partners regardless of the sex of the index case. The study conducted in August 1985-June 1987 involved individuals in 244 households of index patients diagnosed with AIDS or ARC. 92 (61.3%) of the 150 male index cases and 57 (73.1%) of the 71 female index cases had an HIV-infected marital partner and the severity of HIV disease (AIDS or ARC) in the index partner was linearly associated with the severity of HIV disease in the spouse. 10 (25.6%) of 39 uninfected wives of HIV-positive men compared with only 1 (7.7%) of 13 uninfected husbands seroconverted during the 1st year of follow- up. 4 of the 11 spouses who seroconverted during this period reported sexual intercourse at a time when their HIV-infected partner had genital ulcers. Of the 264 children under 10 years of age from 154 households with an HIV-positive adult who were also evaluated as part of this study 39 (14.8%) were infected--26 had ARC and 13 had asymptomatic infection. Only 3 of the infected children were older than 5 years of age; the mean was 24.9 months. In all cases transmission in children was attributable to HIV infection in the mother. These findings suggest a need for more aggressive counseling to reduce the sexual transmission of HIV infection to uninfected partners. 46 of 52 discordantly infected couples followed for 1 year continued to have unprotected vaginal intercourse--a factor that certainly contributed to the high concordance of HIV infection among the couples in this study.

Clinical and epidemiological features of HIV infection at a referral clinic in Zambia

Abstract: Among 1,350 patients with serologically confirmed HIV-1 infection evaluated at the Dermatovenerealogy Clinic, University Teaching Hospital. Lusaka, through March 1987, 125 (9.3%) had AIDS, 1,178 (87.3%) had AIDS-related complex, and 46 (3.5%) were asymptomatic. The male to female ratio of cases was 1.5:1 and women were younger (mean age of 26.2 years) than were men (mean age of 31.2 years). HIV-infected persons had significantly more lifetime sex partners than uninfected persons; other risk factors were a prior history of venereal disease, blood transfusion, travel abroad, and a positive syphilis serology. Clinical features in decreasing order of frequency were weight loss, persistent generalized lymphadenopathy, chronic cough, multidermatomal herpes zoster, diarrhea, recurrent fevers, tuberculosis, and oropharyngeal candidiasis. The WHO clinical case definition for the diagnosis of AIDS had a low positive predictive value for the 125 Zambians with AIDS, but among all those infected with HIV, the positive predictive value was 76.4%. Thirty (35.3%) of 85 patients who were HIV seronegative when first examined acquired HIV infections during a 12- to 39-month (means = 21.8 months) period of observation. Heterosexual intercourse unrelated to prostitution appears to be the major mode of HIV transmission in Lusaka.

Impact of human immunodeficiency virus on transmission and severity of tuberculosis

Abstract: It is now clear that tuberculosis is one of the major diseases associated with human immunodeficiency virus (HIV) infection and the acquired immune deficiency syndrome both in developing countries and in disadvantaged groups in the northern hemisphere. In the USA, and probably several other countries, the annual incidence of tuberculosis is rising as a result of the HIV epidemic. This is probably a result of an increase in both pulmonary and, especially, extrapulmonary tuberculosis, due to reactivation of latent infections, but a secondary increase in the infection rate is also possible. The hard-won gains in tuberculosis control of the last 30 years are thus in jeopardy. This article focuses on the effect HIV is likely to have on the known risk factors for infection with Mycobacterium tuberculosis and for reactivation. Whilst HIV-associated tuberculosis may be indistinguishable from HIV-negative disease, it is likely in other cases to present diagnostic difficulties, to respond poorly to treatment with more adverse effects, and to result in high early mortality, although this may not be due directly to tuberculosis. HIV-associated tuberculosis thus represents a major challenge to physicians, especially in developing countries, but like other forms of tuberculosis it is (i) treatable and (ii) preventable.

Malaria in an urban and a rural area of Zambia

Abstract: Children in Lusaka and in a rural area in central Zambia were examined during November 1984 and April 1985 to assess the effect of urbanization on malaria transmission. Of 423 urban children examined in November, 2·4% had scanty parasitaemia, and low titres of malarial antibodies were found in 46%. These proportions increased in April to a parasite rate of 10·3% and malaria antibodies were detected by indirect fluorescent antibody tests (IFAT) in 62%. The presence of malaria antibodies was positively associated with journeys outside the main towns. Examination of paired sera from the 2 periods showed an association between a history of malaria and an increased antibody titre, but failed to show an association between travel outside the main towns and conversion from a negative to a positive IFAT. The spleen rate in children under 15 years old in Lusaka was 3%, indicating hypoendemic malaria. In rural children the parasite rate was 10% and 27% in the 2 seasons, respectively, and over 97% of the children had malaria antibodies. The spleen rate was 20%, indicating mesoendemic malaria. It is concluded that there is only low transmission of malaria in Lusaka so that many people do not develop resistance and are therefore at risk of severe attacks if they do become infected. Possible measures to protect the urban population are discussed.

Distribution and diel activity patterns of Glossina fuscipes fuscipes Newstead on Rusinga Island and mainland in Mbita, Kenya

Abstract: A study of population ecology and vectorial capacity of Glossina fuseipes fuscipes Newstead was initiated on Rusinga island and mainland of Mbita Division, South Nyanza District, Kenya. As part of the overall study, investigations into fly distribution and diel activity patterns were carried out using biconical traps. The distribution of flies was found to be confined to a strip of dense vegetation of several metres in width along the lake shore. Trap catches indicated unimodal diel activity patterns for both sexes. Catches were recorded between 0700 and 1900 hr with peaks for females at 0900 hr and for males at 1000 hr. Of the physical factors (solar radiation, relative humidity, temperature and windspeed), solar radiation was found to be the main factor significantly influencing the catches of both males and females during the day. For males Y = −29.46 + 6.30X1 + 0.40X2, (r2 = 0.59, P = 0.0053 and P = 0.0425, where X1 = solar radiation and X2 = relative humidity, respectively). For females, Y = 3.63 + 5.13X1 (r2 = 0.20, P= 0.0960, where X1 = solar radiation).

Application of insecticides on cotton in Zambia : timing of spray applications

Abstract: The timing of insecticide spray application was evaluated to improve the management of cotton pests. The results showed that early spraying for Heliothis management on cotton in Zambia may not be entirely needed in all seasons and in all cotton growing areas of Zambia. The Heliothis infestation generally increased during the tenth week after germination coinciding with the flowering of cotton so the farmers in most cases could avoid the first or second spray starting at seventh or ninth week after the germination of cotton as currently recommended for routine sprays. In field trials, the economic threshold for Heliothis a key pest of cotton in Zambia was found to be 0.50 eggs per plant, when three to four sprays gave similar yields to five routine sprays. In all trials, the routine five sprays never provided significantly higher yields than scouting‐based treatments. The optimum cotton yields were obtained by applying 30 g a.i./ha with an ‘Electrodyn’ sprayer as compared with 57 ga.i./ha of the s...

Long-term preservation of whole blood samples for flow cytometry analysis in normal and HIV-infected individuals from Africa.

Abstract: A whole blood method requiring less than 4 ml of heparinized blood was developed to assess the practicality of preparing whole blood samples that could be easily stored, transported and readily used to determine the lymphocyte phenotypes and proliferation responses of individuals from remote areas who are infected with the human immunodeficiency virus. Minor modifications in standard whole blood procedure for lymphocyte phenotyping have significantly increased the stability of light scatter and fluorescence intensity of the cells for subsequent flow cytometry (FC) analysis. These changes include removal of lysis solution prior to fixation, fixation of monoclonal antibody-stained cells in 1% paraformaldehyde for 30 minutes and storage of fixed samples in medium containing 1% bovine serum albumin. Lymphocyte subsets and their functional subsets could reliably be determined on samples stored for up to 4 weeks. Further, blood samples could be kept at room temperature for up to 96 hours or at ambient temperature during transportation from Africa before staining for FC without affecting their quantitation. While samples could be processed for FC analysis under field-laboratory conditions, proliferation assays could only be performed on samples that were transported within 48 hours of their collection. The whole blood method saves time and expense and decreases the volumes of blood required to perform phenotypic analysis and functional assays on specimens collected in remote areas.

Antibody responses of adults, adolescents, and children to a plasma-derived hepatitis B vaccine in a rural African setting.

Abstract: A field trial of a plasma-derived hepatitis B vaccine in five rural villages in Zambia was analyzed to determine if adults in a rural African setting respond to this vaccine as well as adults in Western countries and to determine the immunogenicity of fewer than the recommended three doses; 255 residents, including 171 who were susceptible to hepatitis B, were vaccinated. Among those who received three vaccine doses, protective levels of antibody to hepatitis B surface antigen (anti-HBs) developed in 67% of adults (ages 21 to 70 years), 87% of adolescents (ages 12 to 19 years), and 100% of children (ages 0 to 11 years). The 67% of vaccinated adults who developed anti-HBs at the protective level was lower than the 96% reported among adults receiving the same vaccine at the same dose and dosage schedule in studies in Western countries. No difference was seen in the response of those receiving two doses compared with those receiving three doses among adults and adolescents, suggesting that a two-dose regimen may be acceptable in these age groups in developing countries to reduce costs and improve compliance. Use of hepatitis B vaccine in a region where prevaccination hepatitis B serologic screening was not available did not appear to increase the number of severity of adverse reactions.

Central venous pressure monitoring for the critically ill in Zambia.

Abstract: The safety and value of central venous pressure (CVP) monitoring in 100 critically ill patients in Zambia was studied prospectively. There were six complications related to insertion, the only serious one being a hydrothorax which was recognized and treated. One patient developed catheter-related septicaemia. CVP measurement altered proposed fluid management in 19 cases, determined management in 31 in whom fluid status was uncertain and confirmed fluid therapy in 50. Additional benefits of central venous catheterization were drug infusion in 33 patients and venous access in 53. Technical problems during monitoring occurred in 54 cases and were due to kinking of the catheter, blockage or inadvertent removal. In our circumstances the risks of cannulation of central veins seem justified in selected patients but good nursing supervision of patients is necessary.

Absolute dating of sedimentation on Lake Torrens with spring deposits, South Australia

Abstract: The travertine structure containing Mountford Spring is in the only surface accumulation of CaCO3 on Lake Torrens, a playa in South Australia. Here the first 14C data on Lake Torrens is presented. 14C ages for travertine samples surrounding Mountford Spring, range from 13770 ± 130 years BP to 22700 ± 290 years BP, giving a time frame for lacustrine sediments wedged in between. In the absence of recent tectonic movements, the old travertine (22700 ±130 years) on the clifftop, surrounded by younger spring deposits (13770 ± 130 years) at a lower level, prove a deflation event at this playa.

Preliminary observations on ovine paratuberculosis (Johne's disease) in Zambia.

Abstract: In an imported flock of sheep from South Africa, an ewe became partially anorexic and gradually losing weight and conditions. The paratuberculosis (Johne's disease) was confirmed on clinical, faecal and histopathological examination. Cultural examination remained doubtful. Serological investigation of other sheep in the flock and at other farm reacted to antibodies of Mycobacterium paratuberculosis on complement fixation test. The study suggests that the disease is actively spreading. This is the first report of ovine paratuberculosis in the Republic of Zambia.

The sensitivity of dermatophytes to griseofulvin.

Abstract: 13 isolates of Trichophyton violaceum and 7 Microsporum langeroni from Zambia and Cameroon were tested in vitro for their sensitivity to griseofulvin. No strain was found resistant. All the 13 T. violaceum were inhibited by 4-8 micrograms/ml while 4 M. langeroni were inhibited by 0.5-1 microgram/ml.

Prevalence of concurrent Chlamydia trachomatis infections among men with gonococcal urethritis in Lusaka.

Abstract: The prevalence of Chlamydia trachomatis infections among male patients with gonococcal urethritis in the sexually transmitted diseases (STDs) clinic at UTH, Lusaka, was determined by two methods to be around 4.7%. Methods used were specific for C. trachomatis (Syva Microtrak), and second isolation of C. trachomatis. The results indicate that with a prevalence rate of 4-7% for concurrent gonococcal and chlamydial infection, it is not financially or medically practical to treat all cases of gonorrhoea in Zambia for possible chlamydial infection, as is advocated in some countries. The findings further suggest that the commercially available Syva Microtrak test should probably be considered positive when one or two monoclonal-stained elementary bodies are seen, rather than ten, to avoid false-negative results.

The determination of selected antibiotics, antibacterials and anticonvulsants by voltammetric and liquid-chromatographic techniques

Abstract: Modern voltammetric techniques such as differential pulse polarography and square wave voltammetry can determine electroactive drugs such as antibiotics and antibacterials over a relatively wide concentration range of approximately three orders of magnitude with detection limits of 10-7 – 10-8 M. Such drugs as raw materials and as they are contained in formulations can be determined rapidly with a minimum of sample treatment prior to electro-analysis. Biological matrices containing drug traces as found in therapeutic drug monitoring, pharmacokinetics and forensic toxicology frequently require solvent extraction and/or other sample treatment procedures prior to voltammetric determination of the drug actives. The selectivity of the these determinations of raw materials formulations and biological matrices towards structurally related process impurities, degradation products and metabolities respectively is generally admitted to be poor.