Minisatellite marker analysis of Trypanosoma brucei: reconciliation of clonal, panmictic, and epidemic population genetic structures. (25/712)

The African trypanosome, Trypanosoma brucei, has been shown to undergo genetic exchange in the laboratory, but controversy exists as to the role of genetic exchange in natural populations. Much of the analysis to date has been derived from isoenzyme or randomly amplified polymorphic DNA data with parasite material from a range of hosts and geographical locations. These markers fail to distinguish between the human infective (T. b. rhodesiense) and nonhuman infective (T. b. brucei) "subspecies" so that parasites derived from hosts other than humans potentially contain both subspecies. To overcome some of the inherent problems with the use of such markers and diverse populations, we have analyzed a well-defined population from a discrete geographical location (Busoga, Uganda) using three recently described minisatellite markers. The parasites were primarily isolated from humans and cattle with the latter isolates further characterized by their ability to resist lysis by human serum (equivalent to human infectivity). The minisatellite markers show high levels of polymorphism, and from the data obtained we conclude that T. b. rhodesiense is genetically isolated from T. b. brucei and can be unambiguously identified by its multilocus genotype. Analysis of the genotype frequencies in the separated T. b. brucei and T. b. rhodesiense populations shows the former has an epidemic population structure whereas the latter is clonal. This finding suggests that the strong linkage disequilibrium observed in previous analyses, where human and nonhuman infective trypanosomes were not distinguished, results from the treatment of two genetically isolated populations as a single population.  (+info)

Prolonged measles virus shedding in human immunodeficiency virus-infected children, detected by reverse transcriptase-polymerase chain reaction. (26/712)

A reverse transcriptase-polymerase chain reaction assay was used to detect measles virus RNA in peripheral blood mononuclear cells, urine, and nasopharyngeal specimens from Zambian children during hospitalization and approximately 1-2 months after discharge. Of 47 children, 29 (61.7%) had prolonged measles virus shedding, as defined by detection of measles virus RNA in > or =1 specimen obtained 30-61 days after rash onset. Ten (90.9%) of 11 human immunodeficiency virus (HIV)-infected children had prolonged measles virus shedding, compared with 19 (52.8%) of 36 HIV-uninfected children (P=.02). Prolonged measles virus shedding did not correlate with levels of measles virus-specific antibody. HIV-infected children with measles may have a prolonged infectious period that potentially enhances measles virus transmission and hinders measles control.  (+info)

Intention to use the female condom following a mass-marketing campaign in Lusaka, Zambia. (27/712)

OBJECTIVES: This report examines intention to use the female condom among men and women in Lusaka, Zambia, who were exposed to mass-marketing of the female condom. METHODS: The study used data from a representative sample of consumers at outlets that sell or distribute the female condom and the male condom. RESULTS: In spite of a high level of awareness of the female condom, use of this method in the last year was considerably lower than use of the male condom. Intention to use the female condom in the future was highest among respondents who had used only the female condom in the last year. CONCLUSIONS: The female condom is likely to be most important for persons who are unable or unwilling to use the male condom.  (+info)

A randomized controlled trial of artemotil (beta-arteether) in Zambian children with cerebral malaria. (28/712)

The efficacy and safety of intramuscular artemotil (ARTECEF) was compared to intravenous quinine in African children with cerebral malaria. This prospective block randomized open-label study was conducted at two centers in Zambia. Subjects were children aged 0 to 10 years of age with cerebral malaria and a Blantyre Coma Score of 2 or less. Ninety two children were studied; 48 received artemotil and 44 quinine. No significant differences in survival, coma resolution time, neurologic sequelae, parasite clearance time, and fever resolution time were seen between the two regimens. Rates for negative malaria smears one month after therapy were similar in both groups. Artemotil was a well-tolerated drug in the 48 patients in this study. It appears to be at least therapeutically equivalent to quinine for the treatment of pediatric cerebral malaria. It has the advantage of being able to be given intramuscularly once daily for only five days.  (+info)

Sexual behaviour and sexually transmitted diseases among young men in Zambia. (29/712)

Sexually transmitted diseases (STDs) are an increasing public health problem in Zambia. About 200 000 cases of STDs are treated annually in the formal health sector. Young people are the most affected by STDs. High-risk sexual behaviour has been identified as the major risk factor for STDs among young people. We conducted interviews and focus group discussions with a purposely selected sample of 126 young men aged between 16 and 26 in Chiawa, rural Zambia. The aim of the interviews and focus group discussions was to explore views about sexual practices and attitudes towards STD. Fifty-eight (59%) young men reported having had pre-marital or extra-marital sexual partners during the past year. The maximum number was five partners for six individuals. Forty-two (43%) had pre-marital or extra-marital sexual partners at the time of the interviews. Focus group discussions revealed that perceptions of manhood encouraged multiple sexual relationships. Twenty-two (23%) reported having suffered from an STD in the past. Seventy-nine (81%) said they were likely to inform their sexual partners if they had an STD. Although condoms were believed to give protection against STDs by the majority (94%), only 6% said they always used condoms. The data suggest that condoms were perceived to affect male potency. These results show that STDs, multiple sexual relationships and unprotected sex are common among the young men of Chiawa. Perceptions that emphasize manhood are widespread and these may negatively affect efforts for positive behavioural change. Health messages that target the young men should take into account the local perceptions and values that seem to sustain risky sexual behaviour.  (+info)

An investigation of heavy metal exposure and risks to wildlife in the Kafue flats of Zambia. (30/712)

Exposure and ecological risks to heavy metals (copper, zinc, manganese, iron) at Lochnivar and Blue Lagoon National Parks in wildlife dependent on the Kafue river contaminated with mining waste was evaluated. Samples included water, fish, grasses and Kafue Lechwe (Kobus leche kafuensis) liver. At both parks copper ranged from 0.03-0.04 mg/l; 3.0-6.0 mg/kg; 11.0-44.0 mg/kg; trace -199.0 mg/kg; while zinc was 0.01 mg/l; 32.0-82.0 mg/kg; 15.0-21.0 mg/kg; and 52.0-138.0 mg/kg; in water, fish, grasses and lechwe, respectively. Manganese ranges were 0.15-0.16 mg/l; 7.0-18.0 mg/kg; 51.0-145.0 mg/kg; and 40.0-53.0 mg/kg while iron ranges were 0.13-0.14 mg/l; 26.0-134.0 mg/kg; 1766.0-1797.0 mg/kg; and 131.0-856.0 mg/kg; in water, fish, grasses and lechwe, respectively. Levels in all samples except water were high indicating potential for adverse effects.  (+info)

Microsatellites reveal high levels of population substructuring in the species-poor Eretmodine cichlid lineage from Lake Tanganyika. (31/712)

This study investigated fine-scale population substructuring in an apparently monogamous, biparental mouth-brooding cichlid. Microsatellite allele frequencies were determined at four polymorphic loci for nine populations of Eretmodus cyanostictus. We provide empirical support for the hypothesis that a species employing this breeding strategy should exhibit high levels of population substructuring. Stretches of sand represent considerable barriers to dispersal and, in contrast to the rock-dwelling cichlids of Lake Malawi, distance alone, along a continuous rocky shoreline, is sufficient to reduce gene flow significantly There was a significant pattern of isolation by distance both along the whole study area and over the stretch of continuous shoreline, suggesting that this species has poor dispersal capabilities and that juveniles establish territories close to their natal site. Despite limited dispersal, E. cyanostictus populations are not significantly more inbred than a more-widely dispersing rock-dwelling cichlid from Lake Malawi. This finding may cast doubt on the hypothesis that polyandry has evolved as a mechanism for maintaining genetic diversity in Lake Malawi cichlids. High levels of substructuring may not always promote high levels of speciation, and other factors, such as the intensity of sexual selection, may be more important in determining the speciation potential of a lineage.  (+info)

Socio-economic, gender and health services factors affecting diagnostic delay for tuberculosis patients in urban Zambia. (32/712)

In-depth interviews regarding health seeking behaviour were conducted with 202 adults registered with pulmonary tuberculosis at the centralized Chest Clinic in Lusaka, Zambia. The median (mean) diagnostic delay was 8.6 (9) weeks, and was significantly associated with the following factors: female sex, lower education, more than six instances of health-seeking encounters, outpatient diagnosis of tuberculosis, and visiting a private doctor or traditional healer. More effective tuberculosis control interventions require novel methods of accessing women and less educated people. Decentralization of public tuberculosis care and improved integration with private sector health providers may also reduce diagnostic delay.  (+info)