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Biomedical subjects

F S Mhalu

Publications and source records attributed to F S Mhalu.

At least 19 recordsLinked to original sources
PubMed2005

Burden of diseases in poor resource countries: meeting the challenges of combating HIV/AIDS, tuberculosis and malaria.

Poverty, ill health and ignorance are closely interlinked and each is a determinant of the other. HIV/AIDS, malaria and tuberculosis are by far the commonest causes of ill-health and death in the poorest countries of the world which happen to be in the tropics and temperate countries in Africa, Asia and South America. Morbidity and mortality from these three diseases have a major socio-economic impact on individuals, communities and nations, due to the vicious cycle of poverty, ill health and ignorance. In Tanzania morbidity due to HIV/AIDS, tuberculosis and malaria leads to irrecoverable losses in productivity, inadequately trained workforce due to absence from training by the sick, heavy health care budgets to treat these otherwise preventable diseases, less competitive economy, higher labour force turnovers and unstable national budgets. If not controlled continuing rise in incidence of HIV/AIDS, malaria and TB may threaten the survival of small enterprises and ability to attract foreign investments leading to a rise in unemployment. Thus, investments in the improvement of health including HIV/AIDS, malaria and TB if done well will bring substantial benefits for the national economy including an increase in productivity. In this paper a review of the impact of HIV/AIDS, TB and malaria in Tanzania is done with an attempt to propose how research can contribute to improved efforts towards more effective prevention and control efforts. The need for multidisplinary research efforts in addressing the three disease conditions is proposed.

Cost of Illness↗
PubMed2003

Lymphocyte subset enumeration in HIV seronegative and HIV-1 seropositive adults in Dar es Salaam, Tanzania: determination of reference values in males and females and comparison of two flow cytometric methods.

The level of CD4(+) T-lymphocytes represents a useful marker with which to monitor the progression of HIV infection. Sex and geographical differences in the reference values of lymphocyte subsets have been reported. We have compared two flow cytometric methods (MultiSET and SimulSET) for the quantification of lymphocyte subsets using whole blood from 92 HIV seropositive and 241 seronegative adults, and determined the reference values of lymphocyte subsets in HIV seronegative Tanzanian subjects. In seronegative Tanzanian subjects, the percentages of CD3(+) and CD4(+) T-lymphocytes and the CD4(+):CD8(+) T-lymphocyte ratios were lower while the percentage of natural killer cells was higher compared to the levels of the corresponding parameters reported for Europeans. Seronegative Tanzanian females had significantly higher levels of CD3(+) and CD4(+) T-lymphocytes and CD4(+):CD8(+) T-lymphocyte ratios compared to seronegative males. The correlation coefficients of CD3(+), CD4(+) and CD8(+) T lymphocyte counts and percentages obtained by the two flow cytometric methods were high. The median values of the number of CD4(+) T-lymphocytes obtained by the two methods were not significantly different. In conclusion, determination of the reference values of lymphocyte subsets in HIV seronegative Tanzanian adults showed significant sex differences and differences in percentage values compared to those reported in certain other geographical areas. There was acceptable agreement in the levels of CD4(+) T-lymphocyte values obtained by the two flow cytometric methods.

Adult↗
PubMed2001

Affordable CD4+ T cell counts by flow cytometry. II. The use of fixed whole blood in resource-poor settings.

We tested the feasibility and precision of affordable CD4+ T cell counting in resource-poor settings using a recently standardised fixative, TransFix in whole blood (WB) by flow cytometry (FCM). The precision of the assays was established under optimal conditions for single-platform FCM such as the volumetric CytoronAbsolute and the bead-based FACSCan. Fresh WB samples from HIV-seropositive and seronegative patients were tested in Tanzania and South Africa, fixed and sent to the UK for reanalysis 7 days later. Correlation, bias and limits of agreements were analysed by linear regression and the Bland-Altman test. Absolute CD4+ T cell counts remained stable for at least 10 days when TransFix was added to WB in 1:10 dilution at 20-25 degrees C, and for 7 days when added in 1:10 or 1:5 dilution to samples stored to mimic 'tropical' conditions at 37 degrees C. Higher temperatures such as 42 degrees C were tolerated for only short periods since the recovery had decreased to 63% by day 3. The reproducibility of lymphocyte subset analysis remained unchanged by TransFix with coefficient of variations <6% for all T cell subsets. Absolute CD4+ T cell counts and CD4+ T cell % values on fixed samples in the UK showed a high correlation with the results using fresh samples in Tanzania (r=0.993 and 0.969, respectively) and with the samples handled in Johannesburg (r=0.991 and 0.981) with minimal bias. Primary CD4 gating using only a single CD4 antibody also remained accurate in TransFixed samples (r=0.999). Thus, TransFix permits optimal fixation and transport of WB samples in the developing world for FCM to local regional laboratories and for quality assurance in international centres. When used together with inexpensive primary CD4 gating, TransFix will allow reliable and affordable CD4+ T cell counting by FCM in resource-poor settings.

Adult↗
PubMed2000

Antimicrobial susceptibility pattern of Vibrio cholerae O1 strains during two cholera outbreaks in Dar es Salaam, Tanzania.

OBJECTIVE: To determine and compare the antimicrobial susceptibility patterns of Vibrio cholerae 01 strains, which were isolated in two cholera epidemics in 1997 and 1999 in Dar es Salaam. METHODS: V. cholerae 01 strains isolated from patients with cholera in Dar es Salaam city during 1997 (94 isolates) and 1999 (87 isolates) were stored on nutrient agar slants at room temperature and antimicrobial susceptibility pattern was determined, using Kirby Bauer method. SETTING: Department of Microbiology and Immunology, Muhimbili Medical Centre, Dar es Salaam, Tanzania. RESULTS: A total of 181 V. cholerae 01 strains were studied during two epidemic periods when tetracycline or erythromycin was used for treatment of patients with severe disease. Among the 94 V. cholerae 01 strains isolated in 1997; 98.6%, 93.6%, 83%, 81.9%, 36.2%, 35.5%, 3.2% were sensitive to ciprofloxacin, tetracycline, ampicillin, erythromycin, nalidixic acid, chloramphenicol and trimethoprim/sulphamethoxazole, respectively. Among the 87 V. cholerae 01 isolates collected in 1999, 100%, 58.6%, 46.0%, 46%, 47.1%, 19.5%, 3.4% were sensitive to ciprofloxacin, tetracycline, ampicillin, erythromycin, chloramphenicol, nalidixic acid and trimethoprim/sulphamethoxazole, respectively. Between 1997 and 1999, there was a significant increase in the proportion of V. cholerae 01 isolates resistant to tetracycline, ampicillin, nalidixic acid and to erythromycin but there was no change for susceptibility to ciprofloxacin and trimethoprim/sulphamethoxazole. CONCLUSION: Significant proportion of V. cholerae 01 strains in Dar es Salaam were resistant to commonly used antimicrobial agents during the two years of the study. Therefore, there is a great need to control the utilisation of antimicrobial agents in cholera control, in addition to continuing carrying out surveillance of antimicrobial resistance as a guide to choice of antimicrobial treatment. Rotational use of the available drugs with regular monitoring of susceptibility may contribute to continuing usefulness of such drugs.

Cholera↗
PubMed1999

Prevalence of HIV infection among hospital patients in north west Tanzania.

In order to estimate hospital HIV prevalence, the economic impact of AIDS on health care and to assess the implications of HIV testing on clinical suspicion of AIDS this hospital based study was done at the government regional hospital of Kagera, Tanzania. Consecutive admissions were recruited into the study, and those consenting had a blood specimen taken, one portion of which was used to aid clinical diagnosis, while the other was tested anonymously for HIV antibodies using two ELISA systems. A short questionnaire was used to specify demographic characteristics, hospital ward of admission and diagnosis of each study subject. The overall age adjusted HIV-1 prevalence was 32.8% (N = 1422) and there was no significant difference in the age adjusted sex specific prevalence. The highest prevalence (53.3%) was found in the 25-34 years age group as well as in the gynaecological and medical wards (41.2% and 40.4%, respectively). The diagnostic category of clinical AIDS had a sensitivity of 11.3% and a specificity of 99.3%, indicating that only 11.3% of the HIV seropositives would have been HIV tested on clinical suspicion of AIDS. Similarly, the HIV-1 antibody sensitivity and specificity for tuberculosis were 5.9% and 97.9%, respectively. Patients who were HIV-1 infected were more likely to have a history of previous hospital admissions, RR = 1.34 (95% CI = 1.16-1.56), and were at an increased risk of developing tuberculosis, RR = 2.02 (95% CI = 1.50-2.70). The diagnostic categories with the highest HIV-1 infection prevalence were clinical AIDS (88.5%), herpes zoster and other HIV-1 skin manifestations combined (85.7%) and pulmonary tuberculosis (58.3%). In conclusion, the prevalence of HIV-1 infection was high among hospitalized patients in Bukoba hospital indicating that the major cause of illness leading to admission to the hospital may have been underlying HIV-1 infection. The findings also indicate that in a high HIV-1 prevalence area, testing for HIV infection on the basis of clinical suspicion of AIDS alone is not sufficient to provide rational care to the majority of HIV infected patients.

AIDS-Related Opportunistic Infections↗
PubMed1998

Acceptability of voluntary HIV testing with counselling in a rural village in Kagera, Tanzania.

A pilot study on acceptability of voluntary HIV testing with counselling was performed in a rural village in Kagera, Tanzania as a potential intervention against HIV transmission. Village residents were prepared by their leaders and subsequently invited to health education group meetings to volunteer for the test. Consenting individuals were interviewed to determine awareness and acceptance of the offer followed by pre-test counselling and taking of a blood sample for subsequent HIV testing. Two months later, the results of the test were returned with post-test counselling coupled with a short interview of a random sample of adults in the village. Of the 245 adults responding to the call, 137 (55.9%) subsequently volunteered. The main reason for volunteering was to know the HIV status (96%). Among those who were aware of the offer, the main reason for not volunteering was that they felt unlikely to catch AIDS, implying that they had a false perception of being at low risk. In this study a significant proportion were willing to volunteer for the HIV test and to receive the results, indicating a moderate level of acceptability. The results also indicate the need for developing innovative ways of enhancing acceptability of voluntary HIV testing with counselling. However, the relationship between knowledge of HIV status and behavioural change is complex and therefore several potential mechanisms may exist by which HIV testing in combination with counselling can influence behaviour. For this reason, people should be given the choice of knowing their HIV status since it may constitute a potential mechanism for influencing behaviour towards reduction of HIV transmission.

Adolescent↗
PubMed1998

Immunological profile of endemic and epidemic Kaposi's sarcoma patients in Dar-es-Salaam, Tanzania.

Kaposi's sarcoma (KS) presents in four clinicopathological types namely classical/sporadic (CKS), endemic African (EKS), iatrogenic (IKS) and that associated with AIDS (AKS). Recently a putative herpes virus (HHV-8) was described and shown to be present in all four types of KS. The immunological status of patients with EKS has been conflicting. In this study total leucocyte counts, total lymphocyte counts and lymphocyte subsets of patients with EKS and AKS were determined by flow cytometry and compared to those of healthy HIV-1 seronegative controls. Results show that 50% of EKS lesions were of nodular type. Patients with EKS had significantly lower levels of CD4+ T- lymphocytes and CD4:CD8 ratio but significantly higher CD8+ T-lymphocytes compared to controls. Patients with AKS had significantly lower levels of CD4+ T-lymphocytes and also CD4:CD8 ratios but significantly higher percentage of CD8+ T-lymphocytes when compared with EKS patients. These findings indicate that in both forms of KS there is a certain degree of immunological disturbance which is more conspicuous in AKS because of HIV infection and suggests that HIV-1 acts synergistically with the aetiological agent (HHV-8) to cause a more aggressive type of KS.

AIDS-Related Opportunistic Infections↗
PubMed1997

Antibiotic susceptibility of group A streptococci in a national consultant hospital in Dar es Salaam: a four year follow-up.

Seventy one Group A streptococcal strains isolated between 1992 and 1995 at Muhimbili Medical Centre in Dar es Salaam were found to be susceptible to penicillin G and cotrimoxazole. All except two strains, which showed intermediate susceptibility, were susceptible to erythromycin. Sixty five strains (91.5%) were resistant to doxycycline. The findings confirm continuing efficacy of penicillin G, erythromycin and contrimoxazole in treating Group A streptococci (GAS). The low prevalence of GAS with intermediate susceptibility to erythromycin and resistance to doxycycline by a majority of the GAS emphasise the need for regular monitoring of antibiotic susceptibility of GAS.

Drug Resistance, Microbial↗
PubMed1996

Evaluation of the FACScount, TRAx CD4 and Dynabeads methods for CD4 lymphocyte determination.

A study to evaluate the performance of the FACScount, TRAx CD4 and Dynabeads methods for the determination of CD4+ T lymphocyte subset levels was conducted in Tanzania as part of a World Health Organization (WHO) collaborative multicenter field evaluation of alternative methodologies for the enumeration of CD4+ T lymphocytes. The objective was to compare the performance of these alternative methods in a developing country setting, against that of flow cytometry as the reference standard. T lymphocyte subset levels were determined in 91 HIV seronegative and 98 HIV-1 seropositive adults using the three alternative methods. CD4+ and CD8+ T lymphocyte counts were determined by all methods except for TRAx CD4 enzyme linked immunosorbent assay (ELISA) which measures CD4+ T lymphocyte levels only. Linear regression analysis was done to correlate the counts obtained by the alternative methods to those obtained by flow cytometry. The overall correlation coefficients of FACScount and Dynabeads CD4+ and CD8+ T lymphocyte counts with those of flow cytometry were high (r > 0.9). A lower correlation (r = 0.631) was obtained when TRAx CD4+ ELISA counts were compared to those of the reference method. These results show that two of these alternative methodologies are suitable for the determination of CD4+ and CD8+ T lymphocyte counts with the use of African blood samples. Since the methods are simpler and cheaper than flow cytometry, they provide an alternative option for the enumeration of T lymphocyte subsets in laboratories with limited facilities.

Adult↗
PubMed1996

Human immunodeficiency virus infection and AIDS in east Africa: challenges and possibilities for prevention and control.

Human immunodeficiency infection and AIDS are a major recent microbial infection in east Africa with serious health and socioeconomic impacts in the region. At present HIV infection and AIDS account for more than 50% of adult medical admissions into some of the national and provincial hospitals as well as for 10-15% of paediatric admissions. AIDS is also at present the commonest cause of death among those aged 15-45 years. Tuberculosis, a closely associated disease to HIV infection, has increased more than three fold in some countries in the region. The prevalence of HIV infection currently ranges from 10-30% among adults in urban areas and from less than 1% to 25% in adults in rural areas; since this prevalence is still rising, the full impact of the AIDS problem in east Africa is yet to be realised. This is different from the situation in many developed countries where AIDS is no longer a priority health issue and where peak prevalences of the infection have been reached. The differences in HIV prevalences between east Africa and developed countries are due to poverty, ignorance, high prevalence of other STDs and associated cultural and traditional practices which prevail and facilitate HIV transmission in the region. While more than 80% of HIV infection in east Africa is transmitted through heterosexual intercourse, 5-15% of cases are perinatally transmitted and the remaining cases are transmitted through blood and blood products. While a lot of scientific advances have been made in immunopathology of AIDS, diagnostics and in social behavioural studies, we are still a long way towards getting curative therapy and or effective preventive vaccines. Recent discovery that use of zidovudine can significantly reduce perinatal HIV transmission is an additional breakthrough. While knowledge and tools for preventing HIV transmission are available in the world, prospects for AIDS control in east Africa appear gloomy unless major efforts are made in the reduction of poverty, ignorance and in the control of other common sexually transmitted diseases.

Adolescent↗
PubMed1996

Serological evidence of Lyme borreliosis in Africa: results from studies in Dar es Salaam, Tanzania.

Investigations were performed on sera from blood donors, pregnant women, patients with polyarthritis and from patients with clinical suspicion of syphilis in Dar es Salaam using Borrelia burgdorferi (Bb) flagellar antigen in a second generation ELISA test from DAKO A/S, Denmark, for specific IgM or IgG antibodies. An IgM and or IgG seropositivity rate of 30/100 (30%), 19/50 (7.2%), 10/20 (50%) and 11/20 (55%) was found in sera from the respective groups. These results compare with a Bb seroprevalence rate of 4/100 (4%), 1/52 (2%) and 363/5024 (7.2%) in blood donors, in pregnant women and in patients investigated serologically for Lyme borreliosis (Lb) respectively in Bergen, Norway, where cases of Lb are detected regularly. The high prevalence of antibodies to Bb flagellar antigen in Dar es Salaam, Tanzania where clinical conditions including erythema migrans, arthritis, mycocarditis and CNS diseases as well as tickbites are found call for further clinical, entomological and laboratory investigations.

Antibodies, Bacterial↗
PubMed1996

Immunohaematological findings in healthy and HIV-1 infected adults in Dar es Salaam, Tanzania.

In order to assess the prognostic value of lymphocyte subsets and immune activation markers in HIV-1 infected Tanzanian patients, peripheral white blood cell(WBC) count, total lymphocytes, CD4+ and CD8+ T-lymphocytes and Beta-2 microglobulin (B-2M) concentrations were determined among healthy HIV-1 seronegative Tanzanian blood donors and in infected Tanzania individuals in different clinical stages of HIV-1 infection. CD4+ T-lymphocytes, CD8+ T-lymphocyte percentages, CD4:CD8 lymphocyte ratios and the concentrations of B-2M were strongly correlated with the clinical stages of HIV-1 infection. These results suggest that B-2M could be a useful prognostic marker in HIV-1 infection in settings where T-lymphocyte subset determinations cannot be done.

Adult↗
PubMed1996

High frequency of sexually transmitted diseases among pregnant women in Dar es Salaam, Tanzania: need for intervention.

In order to determine the prevalence and characteristics of sexually transmitted diseases (STDs) in pregnant women (PW) attending a primary health care antenatal clinic (ANC) in metropolitan Dar es Salaam, Tanzania, a randomly selected sample of PW in their second or third trimesters were invited to participate at their first visit. They were interviewed using a questionnaire and underwent genital examination. Genital swabs were obtained for microscopy and/or culture isolation of Candida albicans, Trichomonas vaginalis, and Neisseria gonorrhoeae. Blood specimens were also obtained for serological testing for syphilis and for antibodies to the human immunodeficiency virus (HIV). A total of 777 PW aged 14 to 40 years were seen. Parities ranged from 0 to 10. Prevalence of syphilis, trichomoniasis, gonorrhoea and HIV infection were 4.0%, 22.7%, 3.6% and 15.2%, respectively. At least one acute STD (excluding HIV infection) was found in 32.8% of the PW. The prevalence of multiple STDs (excluding HIV infection) was higher in teenagers (45.3%, 77/170) than in PW in other age groups (29.2%, 177/607) (p < 0.001). The prevalence of HIV infection in teenage PW was 10.0%. Most STDs were least prevalent in PW who were married monogamously. Of the 732 PW who had one or more genital infections (including infection with Candida species), 669 (91.4%) had one or more genital complaints. However, most of the genital complaints were not disease specific. Since this study has shown that the prevalences of acute STDs were high in PW, especially in teenagers, it is recommended that all PW in Tanzania should be screened for STDs syndromically including the use of appropriate clinical and laboratory examination whenever possible.

Adolescent↗
PubMed1995

Antistreptolysin O and antideoxyribonuclease B titres in blood donors and in patients with features of nonsuppurative sequelae of group A streptococcus infection in Tanzania.

Antistreptolysin O (ASO) and antideoxyribonuclease B (ADN B) titres were determined on sera from blood donors in Dar es Salaam, Tanzania and from Bergen, Norway and were compared with titres in patients with features of postgroup A streptococcal diseases in Dar es Salaam. The upper limit of normal ASO titres in Dar es Salaam was 200 mu/ml and for ADN B it was 300 u/ml while in Bergen the upper limit of normal ASO titre was 250 u/ml and that of ADN B was 100 u/ml. Titres of ASO in Dar es Salaam and Bergen were consistent with those from sub-Saharan Africa and from other continents. Upper limit of normal ADN B titres in adults in Dar es Salaam were higher than those in Bergen probably due to higher frequencies of group A streptococcal skin infections in Dar es Salaam than in Bergen. Patients with features of postgroup A streptococcal diseases in Dar es Salaam had antibody titres above the upper limits of normal in 32.8% of the patients for ASO and in 45.9% for ADN B. ASO and ADN B titres or ASO and any other reliable test for antibody to group A streptococcus should be utilised together in providing strong evidence of recent infection with the group A streptococcus or of postgroup A streptococcal disease.

Adult↗
PubMed1993

Incidence of HIV-1 infection among adults in the Kagera region of Tanzania.

The results of a population-based follow-up study are presented. The baseline study which started in August 1987, was carried out to determine the prevalence of human immunodeficiency virus (HIV-1) infection in the Kagera region of Tanzania. A multistage cluster sampling technique was adopted in the selection of the study population. In the follow-up survey which started in June 1988, members of the same study population were revisited and studied in order to determine the incidence of HIV-1 infection among those who were HIV seronegative in the initial survey. HIV serology was conducted by using enzyme-linked immunosorbent assay and all positive sera were confirmed by the Western blot technique. A total population of 1316 adults aged 15-54 years was studied, constituting an average follow-up response rate of 69% in the rural areas and of 59% in the urban area. The overall incidence of HIV-1 infection among the adult population sample was 13.7 per 1000 person-years at risk with the highest incidence in the urban zone (47.5 per 1000 person-years at risk) and the lowest incidence in one of the three rural zones (4.9 per 1000 person-years at risk). The age-specific annual incidence was highest in the age group 25-34 years for males and in the age group 15-24 for females. From these results it was estimated that the number of newly infected adults in the region each year is about 8200 with a range between 5400 and 11,000 corresponding to the 95% confidence limits on the overall incidence.(ABSTRACT TRUNCATED AT 250 WORDS)

Acquired Immunodeficiency Syndrome↗
PubMed1992

Laboratory studies on Yersinia pestis during the 1991 outbreak of plague in Lushoto, Tanzania.

Thirty-one specimens from patients involved in an outbreak of plague were cultured. Suspicious isolates were presumptively identified by colonial characteristics, simple strains and by API 20E, and confirmed by inoculation into white mice. Antimicrobial susceptibility testing was also done. The isolation rate of Y. pestis was 22.6%. All isolates were uniformly sensitive to tetracycline, streptomycin, sulphadimidine and chloramphenicol; moderately sensitive to erythromycin, and resistant to trimethoprim. Y. pestis was confirmed as a cause of the epidemic and sensitivity of Y. pestis to the four antimicrobial agents used was demonstrated. It is recommended that laboratories in zonal hospitals serving areas with plague foci should be provided with facilities for isolation and preliminary identification of Y. pestis in order to speed up diagnosis of plague outbreaks. Confirmation of the identity, biotyping and antibiotic susceptibility testing should be undertaken in a well established national reference laboratory. This appears to be the first publication on bacteriological investigations of human plague in Tanzania.

Animals↗
PubMed1992

Alternative confirmatory strategies in HIV-1 antibody testing.

Alternatives to confirmation of human immunodeficiency virus (HIV)-1 seropositivity by Western blot analysis were evaluated retrospectively using combinations of six anti-HIV-1 screening assays, including four enzyme-linked immunosorbent assays (ELISA) and two simple tests (a rapid dot immunoassay and an agglutination assay), according to an algorithm where sera are first screened by one assay and those repeatedly reactive on this assay are tested repeatedly by a second assay. Two panels of sera collected in Dar es Salaam, Tanzania, were used. Panel 1 was composed of 1,465 consecutive blood donor sera of which 99 (6.8%) were confirmed HIV-1 antibody positive, and panel 2 was composed of sera from 396 consecutively admitted patients at two medical wards of which 116 (29.3%) were confirmed HIV-1 antibody positive. Sera reactive on any of the six screening assays were also tested by a confirmatory Western blot assay. The sensitivity of the assays at the initial valid testing were as follows: Abbott 99.5%, Behring 99.5%, Organon 97.7%, Wellcozyme 100%, HIV CHEK-1 95.8%, and Serodia 95.8%. After repeat testing of sera that initially gave false-negative results all assays showed 100% sensitivity except HIV CHEK-1 (98.6%). The specificities after repeat testing were between 99.6 and 99.9% for all assays except for the Behring ELISA (98.1%). Several combinations of screening assays were found to give the same diagnostic accuracy as the screening assay followed by Western blot analysis. We conclude that an alternative confirmatory strategy can be fully satisfactory for some testing purposes.

Agglutination Tests↗