Zambian Population Research Articles

Ankylosing spondylitis in three Sub‐Saharan populations: HLA‐B*27 and HLA‐B*14 contribution

Ankylosing spondylitis (AS) is a chronic inflammatory rheumatic disease affecting predominantly the axial skeleton and sacroiliac joints, of unknown etiology and strongly associated with human leukocyte antigen (HLA)-B27 (1). The clinical presentation of AS in Sub-Saharan populations is rare (2) due to the very low frequency in Africans of the most important genetic predisposing condition for the development of AS, HLA-B27 antigen, comparing to Europeans or North Americans. However, the influence of HLA markers other than B27, like other HLA-B alleles, has not been investigated thoroughly in these regions. We previously conducted two studies in the Togolese and Zambian population that showed genetic evidence for implication of HLA-B*1403 in AS (3, 4). This allele was found in 50% of the AS patients from Togo and absent in healthy controls, whereas two of the three AS patients from Zambia were B*14:03 positive and none of the healthy controls had this allele. Here, 14 cases of AS were diagnosed over a 2-year period in the University Hospital Yalgado Ouedraogo of Ouagadougou (Burkina Faso, Africa) according to the New York criteria (5). We also selected 27 controls matched for sex, age and ethnic origin. None of the patients or the controls showed other types of spondyloarthropathies (SpA) (reactive arthritis, arthritis associated to human immunodeficiency virus, psoriasic arthritis or undetermined SpA). A sample of peripheral blood per subject was taken in the University Hospital Yalgado Ouedraogo using PAXgene Blood DNA Tubes (Qiagen, Valencia, CA) for blood collection and stabilization. DNA purification and HLA-B genotyping with the HLA-SSO Typing Kit (Tepnel Lifecodes, Stanford, CT) was performed at the Histocompatibility Unit of the Hospital Universitario Central de Asturias, Oviedo, Spain. We analyzed the HLA-B alleles’ distribution between AS patients and controls from Burkina Faso. One finding was the presence of B*14:03 in two of the 14 AS patients (14.3%) and its absence in the 27 controls. We also found that the presence of B*27:05 was increased in AS patients compared with controls (50% vs 3.7%, P = 0.001, OR = 26). To date, we have described 25 AS patients from Sub-Saharan populations (n = 3, 8 and 14 from Zambia, Togo and Burkina Faso, respectively), and we have compared the HLA-B alleles distribution to healthy subjects (n = 204; 92 Zambians, 85 Togoleses and 27 from Burkina Faso), all of them without other types of SpA. Although the distribution of each HLA-B allele (B*27:05 and B*14:03 ) was distinctive, we concluded that the influence of HLA-B alleles in AS is homogenous in all populations studied (B*14:03+B*27:05 ) (Table 1). In this regard, we take into account the three AS Sub-Saharan populations and showed that the frequency of HLA-B*14:03 or HLA-B*27:05 alleles was significantly increased in AS patients compared to healthy controls (32% vs 0.2%, P = 5.65 × 10−16, OR = 191.5) (Table 1). It has been argued that the AS in Sub-Saharan populations seems to represent a subgroup of the disease (2). The disease has a similar clinical presentation compared to Western Europe and North America, but according to several studies the AS patients are older at onset of the disease, the most of them lack extra-articular manifestations and many affected subjects do not have a family history of AS (2). To date, we have analyzed 25 AS cases in Sub-Saharan populations and the average age at the beginning of the disease was 26 years, similar to the other parts of the world. Moreover, the most important issue for assuming that AS in African is a subgroup of the disease was that the most of Sub-Saharan African patients were HLA-B27 negative, and this subtype was rare in black Africans (2). However, we showed that the influence of HLA class I allotypes is homogeneous in all populations studied, suggesting a common mechanism of predisposition to AS. The pathogenic behavior of B*14:03 and B*27:05 may be related to a common feature, taking on that in both cases they are involved in the disease mechanism. The objective of future studies should be evaluate features compatibles with the association of B*14:03 and B*27:05 with AS. Accordingly, results inconsistent with a pathogenic role of misfolding or free surface-expressed heavy chain have been described (6), showing relevance of peptide binding as a important purpose of study for searching common features between B*14:03 and B*27:05. Structural studies have also been reported in order to shed light on the causes of association of these alleles with AS (7, 8). It has been observed that alloreactive cytotoxic T-lymphocyte may be generated against cells expressing B*14:02 (not associated with AS) that cross-react with HLAB27 molecules, suggesting that many shared ligands adopt antigenically similar conformations when bound to different

From Stigma to Intervention

Pentecostals and Charismatics in Zambia continue to contribute greatly on matters that are at the heart of Zambia’s Socio-economic problems. More importantly, their engagement with HIV/AIDS and related issues in the last decade has been profound. The scale of their engagement varies based on the capacity of individual churches. Whether on a congregational or national level, they are actively developing means by which they can help sufferers and their families have a sense of hope. What is clear is that from an initial detached attitude towards civic engagement, privileging evangelism in the preparation of the imminent return of Christ, there is now a balanced message that is accompanied by an engagement with physical problems that the Zambian population continue to face, in this case HIV/AIDS, among other things.

Loss of genetic diversity in an outbreeding species: small population effects in the African wild dog (Lycaon pictus)

Genetic studies on the endangered African wild dog (Lycaon pictus) have primarily focused on the few remaining large and viable populations. However, investigations on the many isolated small African wild dog populations might also be informative for species management because the majority of extant populations are small and may contain genetic variability that is important for population persistence and for species conservation. Small populations are at higher risk of extinction from stochastic and deterministic demographic processes than larger populations and this is often of more immediate conservation concern than loss of genetic diversity, particularly for species that exhibit out-breeding behaviour such as long distance dispersal which may maintain gene flow. However, the genetic advantages of out-breeding behaviour may be reduced if dispersal is compromised beyond reserve borders (edge effects), further weakening the integrity of small populations. Mitochondrial DNA and 11 microsatellite genetic markers were used to investigate population genetic structure in a small population of out-breeding African wild dogs in Zambia, which occupies an historical dispersal corridor for the species. Results indicated the Zambian population suffered from low allelic richness, and there was significant evidence of a recent population bottleneck. Concurrent ecological data suggests these results were due to habitat fragmentation and restricted dispersal which compromised natural out-breeding mechanisms. This study recommends conservation priorities and management units for the African wild dog that focus on conserving remaining levels of genetic diversity, which may also be applicable for a range of out-breeding species.

Prevalence of helminths of importance for human health in stray dogs in Lusaka Zambia

Stray dogs destined for euthanasia were collected from January 2010 through December 2010 to determine the presence of zoonotic gastrointestinal (GI) helminths in Lusaka district. A total of 33 stray dogs (male=18, female=15) were collected, euthanized and necropsy information obtained via helminthological approach. About 100% (33/33) were infected with one or more helminth parasites. Multiple infections involving nematodes and cestodes were the most prevalent (63.6%) followed by nematodes only (33.3%) with cestodes only being the least prevalent (3.0%). The most prevalent GI helminth parasite was Ancylostoma caninum (93.9%) with the least prevalent being Toxocara canis (6.1%). No positive case of Trichinella spiralis was reported from direct trichinoscopy examination of striated muscles. The mean count per dog of A. caninum was 44.45 (SD ±58.0) with a range of 0 to 223. The presence of three important zoonotic gastrointestinal helminths (A. caninum, T. canis and Dipylidium caninum) reported in this study underscores the importance of controlling helminthosis in stray dogs and stresses the need to establish a national control programme for parasitic diseases in this dog population. This can be achieved through the vigorous implementation of the laws governing control of stray dogs and regular deworming of owned dogs. Controlling zoonotic helminths in dogs will ensure a minimal public health risk from the dog population in Zambia since they act as a source of infection to other dogs as well as humans

Age Determination by Back Length for African Savanna Elephants: Extending Age Assessment Techniques for Aerial-Based Surveys

Determining the age of individuals in a population can lead to a better understanding of population dynamics through age structure analysis and estimation of age-specific fecundity and survival rates. Shoulder height has been used to accurately assign age to free-ranging African savanna elephants. However, back length may provide an analog measurable in aerial-based surveys. We assessed the relationship between back length and age for known-age elephants in Amboseli National Park, Kenya, and Addo Elephant National Park, South Africa. We also compared age- and sex-specific back lengths between these populations and compared adult female back lengths across 11 widely dispersed populations in five African countries. Sex-specific Von Bertalanffy growth curves provided a good fit to the back length data of known-age individuals. Based on back length, accurate ages could be assigned relatively precisely for females up to 23 years of age and males up to 17. The female back length curve allowed more precise age assignment to older females than the curve for shoulder height does, probably because of divergence between the respective growth curves. However, this did not appear to be the case for males, but the sample of known-age males was limited to ≤27 years. Age- and sex-specific back lengths were similar in Amboseli National Park and Addo Elephant National Park. Furthermore, while adult female back lengths in the three Zambian populations were generally shorter than in other populations, back lengths in the remaining eight populations did not differ significantly, in support of claims that growth patterns of African savanna elephants are similar over wide geographic regions. Thus, the growth curves presented here should allow researchers to use aerial-based surveys to assign ages to elephants with greater precision than previously possible and, therefore, to estimate population variables.

Availability and distribution of, and geographic access to emergency obstetric care in Zambia

Objective To assess the availability and coverage of emergency obstetric care (EmOC) services in Zambia. Methods Reported provision of EmOC signal functions in the Zambian Health Facility Census and additional criteria on staffing, opening hours, and referral capacity were used to classify all Zambian health facilities as providing comprehensive EmOC, basic EmOC, or more limited care. Geographic accessibility of EmOC services was estimated by linking health facility data with data from the Zambian population census. Results Few Zambian health facilities provided all basic EmOC signal functions and had qualified health professionals available on a 24-hour basis. Of the 1131 Zambian delivery facilities, 135 (12%) were classified as providing EmOC. Zambia nearly met the UN EmOC density benchmarks nationally, but EmOC facilities and health professionals were unevenly distributed between provinces. Geographic access to EmOC services in rural areas was low; in most provinces, less than 25% of the population lived within 15 km of an EmOC facility. Conclusion A national Health Facility Census with geographic information is a valuable tool for assessing service availability and coverage at national and subnational levels. Simultaneously assessing health worker density and geographic access adds crucial information.

Natural microbe-mediated refractoriness to Plasmodium infection in Anopheles gambiae.

Malaria parasite transmission depends on the successful transition of Plasmodium through discrete developmental stages in the lumen of the mosquito midgut. Like the human intestinal tract, the mosquito midgut contains a diverse microbial flora, which may compromise the ability of Plasmodium to establish infection. We have identified an Enterobacter bacterium isolated from wild mosquito populations in Zambia that renders the mosquito resistant to infection with the human malaria parasite Plasmodium falciparum by interfering with parasite development before invasion of the midgut epithelium. Phenotypic analyses showed that the anti-Plasmodium mechanism requires small populations of replicating bacteria and is mediated through a mosquito-independent interaction with the malaria parasite. We show that this anti-Plasmodium effect is largely caused by bacterial generation of reactive oxygen species.

Virtual Surgical Pathology in Underdeveloped Countries: The Zambia Project

Only 1 surgical pathology laboratory is available in Zambia, a country with a population of 12 million people. Since 2004 the Italian association of pathologists Patologi Oltre Frontiera has been working to create a virtual laboratory through the use of telemedicine. The project has involved staining histologic preparations on site, with the interpretation of imaged slides performed abroad through telepathology. Starting in April 2007, all surgical specimens obtained in Mtendere Mission Hospital, Chirundu, Zambia, were submitted for microscopic examination through whole-slide scans. Two independent Italian pathologists evaluated the cases by means of satellite connection and the final diagnoses were sent to Zambian clinicians via the internet. This article describes the spectrum of diagnoses made via telepathology for the Zambian population. Also, we analyze the concordant and discordant data between this telepathology method and traditional microscopy in a developing country. Moreover, we provide possible solutions for providing pathology services in other underdeveloped countries.

Virtual Surgical Pathology in Underdeveloped Countries: The Zambia Project

Only 1 surgical pathology laboratory is available in Zambia, a country with a population of 12 million people. Since 2004 the Italian association of pathologists Patologi Oltre Frontiera has been working to create a virtual laboratory through the use of telemedicine. The project has involved staining histologic preparations on site, with the interpretation of imaged slides performed abroad through telepathology. Starting in April 2007, all surgical specimens obtained in Mtendere Mission Hospital, Chirundu, Zambia, were submitted for microscopic examination through whole-slide scans. Two independent Italian pathologists evaluated the cases by means of satellite connection and the final diagnoses were sent to Zambian clinicians via the internet. This article describes the spectrum of diagnoses made via telepathology for the Zambian population. Also, we analyze the concordant and discordant data between this telepathology method and traditional microscopy in a developing country. Moreover, we provide possible solutions for providing pathology services in other underdeveloped countries.

Comparative Intradermal Tuberculin Testing of Free-Ranging African Buffaloes (Syncerus caffer) Captured forEx SituConservation in the Kafue Basin Ecosystem in Zambia

Bovine tuberculosis (BTB) is endemic in African buffaloes (Syncerus caffer) in some National Parks in Southern Africa, whilst no studies have been conducted on BTB on buffalo populations in Zambia. The increased demand for ecotourism and conservation of the African buffalo on private owned game ranches has prompted the Zambian Wildlife Authority (ZAWA) and private sector in Zambia to generate a herd of “BTB-free buffaloes” for ex situ conservation. In the present study, 86 African buffaloes from four different herds comprising a total of 530 animals were investigated for the presence of BTB for the purpose of generating “BTB free” buffalo for ex-situ conservation. Using the comparative intradermal tuberculin test (CIDT) the BTB status at both individual animal and herd level was estimated to be 0.0% by the CIDT technique. Compared to Avian reactors only, a prevalence of 5.8% was determined whilst for Bovine-only reactors a prevalence of 0.0% was determined. These results suggest the likelihood of buffalo herds in the Kafue National Park being free of BTB.

Zambia 2007: Results from the Demographic and Health Survey

Summary data on Zambia's population, fertility, contraception, postpartum intervals and breast feeding, and infant mortality are provided in tables, bar graphs, line graphs, and pie charts. Statistics were obtained from the Zambia Demographic and Health Survey for 1992 on 6209 households and interviews with 7060 women aged 15-49 years. General population characteristics are provided for size, birth rate, death rate, growth rate, life expectancy, literacy, urbanization, and gross national produce per capita. Women's educational levels are compared for the urban and rural population. Fertility trends are compared between 1955 and 1992, and differentials are expressed in terms of urban-rural and educational level differences. Fertility is also given for specific age groups in five-year intervals. Fertility preferences are provided in a line graph by age of mother and number of living children. Bar graphs express the desire to stop childbearing among currently married women. The planning status of women is given by the number of living children: want child soon, want child later, don't know when child will be wanted, undecided, want no more, sterilized, infertile, and no information. Contraceptive prevalence for modern versus traditional methods, charts show differences by urban or rural residence and educational level. Line graphs show contraceptive prevalence by age and parity. A recent source of supply data is provided by type of modern method used. Knowledge, ever used of contraceptive methods, and current use are provided by type of method used. Intention to use contraception among currently married nonusers is provided in terms of number of living children. The reasons for future nonuse are show by gross age group. Current marital status is given by 5-year group. Differences in age at first birth are displayed by urban-rural residence and educational level. The percentage using contraception is given by marital status. Duration of postpartum interval is shown as well as differences in breast feeding and amenorrhea by urban-rural residence and educational level. Trends in infant mortality are show as well as differences by urban-rural residence and educational level. The mean number of children ever born and surviving are given by age of the mother.

Posters

Background: The BAT (Paradis, 1987) is an assessment tool for Aphasia, an acquired language disorder caused by focal brain lesion which affects comprehension, production, spoken and written lan-guage.Despite extensive works in the field of aphasia, there has to date been no work undertaken on aphasic manifestation on the Zambian population in the southern region of Africa. Aim: Not a mere translation but adaptation of the BAT into Eng-lish-Bemba. Method: Ten control subjects and ten individuals with speech problems 3 months post stroke, matched on age, gender and education will be assessed on the different tasks of the adapted version of the BAT English-Bemba. Results: Control subjects are expected to score ceiling as opposed to the individuals with speech problems. Low scores on the different tasks will direct the screening of aphasia and draw attention to the different impairments. Conclusion: This tool will serve as a valid, reliable and adequate assessment tool which is not only time and cost effective, but sensitive to Zambia's unique culture and linguistic population. Findings will also not only aid in future diagnosis or research but can also be used to motivate and devise particular treatment and rehabilitation approaches thus improving the quality of life by 'delivering 21st century stroke care'.

Strengthening Community Involvement: Partnering with Indigenous Faith-Based Organizations to Develop Sustainable Partnerships in Zambia

This article examines the role of faith-based organizations (FBOs) in delivering HIV/AIDS services to the population of Zambia. It outlines the causes of HIV transmission, the development of community initiatives to provide services and education programs to underserved families and orphans affected by the disease, and activities of multinational organizations as they partner with FBOs to strengthen education programs, provide for orphans, deliver services, and develop community relationships. The paper suggests strategies for strengthening partnerships, identifies problems that affect the implementation of strategies, and makes recommendations for developing sustainable community relationships.

Home-based voluntary HIV counselling and testing found highly acceptable and to reduce inequalities

BackgroundLow uptake of voluntary HIV counselling and testing (VCT) in sub-Saharan Africa is raising acceptability concerns which might be associated with ways by which it is offered. We investigated the acceptability of home-based delivery of counselling and HIV testing in urban and rural populations in Zambia where VCT has been offered mostly from local clinics.MethodsA population-based HIV survey was conducted in selected communities in 2003 (n = 5035). All participants stating willingness to be HIV tested were offered VCT at home and all counselling was conducted in the participants' homes. In the urban area post-test counselling and giving of results were done the following day whereas in rural areas this could take 1-3 weeks.ResultsOf those who indicated willingness to be HIV tested, 76.1% (95%CI 74.9-77.2) were counselled and received the test result. Overall, there was an increase in the proportion ever HIV tested from 18% before provision of home-based VCT to 38% after. The highest increase was in rural areas; among young rural men aged 15-24 years up from 14% to 42% vs. for urban men from 17% to 37%. Test rates by educational attainment changed from being positively associated to be evenly distributed after home-based VCT.ConclusionsA high uptake was achieved by delivering HIV counselling and testing at home. The highest uptakes were seen in rural areas, in young people and groups with low educational attainment, resulting in substantial reductions in existing inequalities in accessing VCT services.

Integrating mental health into primary health care in Zambia: a care provider's perspective.

BackgroundDespite the 1991 reforms of the health system in Zambia, mental health is still given low priority. This is evident from the fragmented manner in which mental health services are provided in the country and the limited budget allocations, with mental health services receiving 0.4% of the total health budget. Most of the mental health services provided are curative in nature and based in tertiary health institutions. At primary health care level, there is either absence of, or fragmented health services.AimsThe aim of this paper was to explore health providers' views about mental health integration into primary health care.MethodsA mixed methods, structured survey was conducted of 111 health service providers in primary health care centres, drawn from one urban setting (Lusaka) and one rural setting (Mumbwa).ResultsThere is strong support for integrating mental health into primary health care from care providers, as a way of facilitating early detection and intervention for mental health problems. Participants believed that this would contribute to the reduction of stigma and the promotion of human rights for people with mental health problems. However, health providers felt they require basic training in order to enhance their knowledge and skills in providing health care to people with mental health problems.RecommendationsIt is recommended that health care providers should be provided with basic training in mental health in order to enhance their knowledge and skills to enable them provide mental health care to patients seeking help at primary health care level.ConclusionIntegrating mental health services into primary health care is critical to improving and promoting the mental health of the population in Zambia.

Low Occurrence of Tuberculosis Drug Resistance among Pulmonary Tuberculosis Patients from an Urban Setting, with a Long-Running DOTS Program in Zambia

We set out to determine the levels of Mycobacterium tuberculosis resistance to first- and second-line TB drugs in an urban population in Zambia. Sputum samples were collected consecutively from all smear-positive, new and previously treated patients, from four diagnostic centres in Ndola between January and July 2006. Drug susceptibility testing was performed using the proportion method against four first- and two second-line TB drugs. Results. Among 156 new cases, any resistance was observed to be 7.7%, monoresistance to isoniazid and rifampicin was 4.5% and 1.3%, respectively. Of 31 retreatment cases, any resistance was observed to be 16.1%, monoresistance to isoniazid and rifampicin was 3.3% for each drug, and one case of resistance to both isoniazid and rifampicin (multidrug resistance) was detected. No resistance to kanamycin or ofloxacin was detected. Conclusion. Although not representative of the country, these results show low levels of drug resistance in a community with a long-standing DOTS experience. Resource constrained countries may reduce TB drug resistance by implementing community-based strategies that enhance treatment completion.

Impact of HIV infection on self-rated health in a high-prevalence popolation with low awareness of own HIV status

Background: Self-rated global health status has been found to be a sensitive marker of declining health and to operate as an independent predictor of survival. This study examines the effect of HIV infection on self-rated health in a population with high prevalence of HIV infection and low awareness of own status of HIV infection. Methods: The data stem from a comprehensive population-based HIV survey conducted in selected urban and rural populations in Zambia in 1996. A total of 1951 males and 2158 females of age more than 14 years were interviewed of which 6% refused to be tested for HIV infection. A logistic regression model was used assuming socio-demographic factors, mental distress and health care use to be associated both with HIV infection and self-rated health. Results: The proportion of persons judging their health status as poor was higher in the rural than in the urban population. Generally no major difference in the proportions of persons rating their health status as poor was observed between sexes. The proportion of poor self-rated health status increased linearly with age. Use of health care services, mental distress and self-perceived risk of HIV infection were negatively associated with self-rated health. Both males and females living in an urban area and males living in a rural area of age more than 24 years who were infected with HIV were about twice as likely to rate their health status as poor compared to respondents who were not infected with HIV. Conclusion: HIV infection had a strong independent negative effect on self-rated health in persons of age greater than 24 years. This measure of people’s subjective health may be used as a valuable “diagnostic” tool in HIV-related care and support programmes, and should be evaluated for use in such services.

Mental distress in the general population in Zambia: Impact of HIV and social factors

BackgroundPopulation level data on mental health from Africa are limited, but available data indicate mental problems to represent a substantial public health problem. The negative impact of HIV on mental health suggests that this could particularly be the case in high prevalence populations. We examined the prevalence of mental distress, distribution patterns and the ways HIV might influence mental health among men and women in a general population.MethodsThe relationship between HIV infection and mental distress was explored using a sample of 4466 participants in a population-based HIV survey conducted in selected rural and urban communities in Zambia in 2003. The Self-reporting questionnaire-10 (SRQ-10) was used to assess global mental distress. Weights were assigned to the SRQ-10 responses based on DSM IV criteria for depression and a cut off point set at 7/20 for probable cases of mental distress. A structural equation modeling (SEM) was established to assess the structural relationship between HIV infection and mental distress in the model, with maximum likelihood ratio as the method of estimation.ResultsThe HIV prevalence was 13.6% vs. 18% in the rural and urban populations, respectively. The prevalence of mental distress was substantially higher among women than men and among groups with low educational attainment vs. high. The results of the SEM showed a close fit with the data. The final model revealed that self-rated health and self perceived HIV risk and worry of being HIV infected were important mediators between underlying factors, HIV infection and mental distress. The effect of HIV infection on mental distress was both direct and indirect, but was particularly strong through the indirect effects of health ratings and self perceived risk and worry of HIV infection.ConclusionThese findings suggest a strong effect of HIV infection on mental distress. In this population where few knew their HIV status, this effect was mediated through self-perceptions of health status, found to capture changes in health perceptions related to HIV, and self-perceived risk and worry of actually being HIV infected.

Fitting the HIV Epidemic in Zambia: A Two-Sex Micro-Simulation Model

BackgroundIn describing and understanding how the HIV epidemic spreads in African countries, previous studies have not taken into account the detailed periods at risk. This study is based on a micro-simulation model (individual-based) of the spread of the HIV epidemic in the population of Zambia, where women tend to marry early and where divorces are not frequent. The main target of the model was to fit the HIV seroprevalence profiles by age and sex observed at the Demographic and Health Survey conducted in 2001.Methods and FindingsA two-sex micro-simulation model of HIV transmission was developed. Particular attention was paid to precise age-specific estimates of exposure to risk through the modelling of the formation and dissolution of relationships: marriage (stable union), casual partnership, and commercial sex. HIV transmission was exclusively heterosexual for adults or vertical (mother-to-child) for children. Three stages of HIV infection were taken into account. All parameters were derived from empirical population-based data. Results show that basic parameters could not explain the dynamics of the HIV epidemic in Zambia. In order to fit the age and sex patterns, several assumptions were made: differential susceptibility of young women to HIV infection, differential susceptibility or larger number of encounters for male clients of commercial sex workers, and higher transmission rate. The model allowed to quantify the role of each type of relationship in HIV transmission, the proportion of infections occurring at each stage of disease progression, and the net reproduction rate of the epidemic (R 0 = 1.95).ConclusionsThe simulation model reproduced the dynamics of the HIV epidemic in Zambia, and fitted the age and sex pattern of HIV seroprevalence in 2001. The same model could be used to measure the effect of changing behaviour in the future.

Influence of HLA-B*5703 and HLA-B*1403 on Susceptibility to Spondyloarthropathies in the Zambian Population

To analyze the distribution of HLA-B alleles and to investigate their contribution in the susceptibility to spondyloarthropathies (SpA) in a sample population from Zambia, in order to determine a relationship between some HLA-B alleles and development of ankylosing spondylitis (AS), reactive arthritis (ReA), or undifferentiated SpA (uSpA). . We selected 72 patients with SpA and found that 46 had uSpA, 23 ReA, and 3 AS. We also selected 92 matched controls; 55 of these had human immunodeficiency virus type I (HIV-I) infection. We found a significant increase in the rate of uSpA and ReA with features of Reiter's syndrome (RS) in HIV-positive individuals who carried the HLA-B*5703 allele (pc < 0.0001 and pc < 0.001, respectively). Among the significant new findings identified were the presence of B*1403 in 2 of the 3 AS patients (pc < 0.05, OR 47), confirming previous data in the Togolese population. The presence of B*5703 and HIV infection may not affect susceptibility to AS and ReA, but they do show an important influence in uSpA and RS. Our findings confirm that HLA-B*1403 is the only factor to increase the risk of AS in a sub-Saharan African population, whereas HLA-B27 was virtually absent in patients with AS.