A systematic review reveals that African children of 15-17 years demonstrate low hepatitis B vaccine seroprotection rates.

Childhood HBV immunization remains globally fundamental to the elimination of hepatitis B virus (HBV). However, monitoring proportions of HBV vaccine seroprotection and their determinants among African Pediatric recipients is crucial. This study sought to verify extent of immune protection accorded by the HBV vaccine in African children of up to 17 years of age by pooling the prevalence of seroprotection reported by primary studies conducted in the Northern, Western, and Southern African regions. We included 19 eligible articles out of the 197 initially downloaded, published from 1999 to 2021 from African Journals Online (AJOL), EMBASE, Scopus, and PubMed. The study protocol was registered with the International Prospective Register of Systematic Reviews (PROSPERO), University of York Centre for Reviews and Dissemination, under the registration number CRD42022361277. Significantly higher (p < 0.0001) proportion of HBV vaccine seroprotection (69.07%) was found among children under 15 years of age than children 15-17 years (32.368%), 95% CI [34.2454-39.0847%]. Whereas successful integration of the HBV vaccine on the extended programs on immunizations (EPI) has been a major achievement in the reduction of HBV infection in Africa, markedly reduced HBV vaccine seroprotection is persistently demonstrated among adolescent children 15-17 years of age. Future studies are required to clarify the need for booster dose vaccination in most at risk populations and age groups.

Staging of COVID-19 disease; using selected laboratory profiles for prediction, prevention and management of severe SARS-CoV-2 infection in Africa-review.

There are many uncertainties on the future management of the coronavirus disease 19 (COVID-19) in Africa. By July 2021, Africa had lagged behind the rest of the world in Covid-19 vaccines uptake, accounting for just 1.6% of doses administered globally. During that time COVID 19 was causing an average death rate of 2.6% in Africa, surpassing the then global average of 2.2%. There were no clear therapeutic guidelines, yet inappropriate and unnecessary treatments may have led to unwanted adverse events such as worsening of hyperglycemia and precipitating of ketoacidosis in administration of steroid therapy. in order to provide evidence-based policy guidelines, we examined peer-reviewed published articles in PubMed on COVID 19, or up-to date data, we focused our search on publications from 1st May 2020 to 15th July, 2021. For each of the studies, we extracted data on pathophysiology, selected clinical chemistry and immunological tests, clinical staging and treatment. Our review reports a gross unmet need for vaccination, inadequate laboratory capacity for immunological tests and the assessment of individual immune status, clinical staging and prediction of disease severity. We recommend selected laboratory tools in the assessment of individual immune status, prediction of disease severity and determination of the exact timing for suitable therapy, especially in individuals with co-morbidities.

Mapping hepatitis B virus genotypes on the African continent from 1997 to 2021: a systematic review with meta-analysis.

Hepatitis B virus (HBV) has ten genotypes (A-J) and over 40 sub-genotypes based on the divergence of ≥ 8% and 4 to < 8% in the complete genome respectively. These genotypes and sub-genotypes influence the disease prognosis, response to therapy and route of viral transmission. Besides, infection with mixed genotypes and recombinant genotypes has also been reported. This study aimed at mapping the de novo genotypes and correlate them with the immigration trends in order to inform future research on the underlying reasons for the relative distribution of HBV genotypes from a large sample size pooled from many primary studies. Data was extracted from 59 full research articles obtained from Scopus, PubMed, EMBASE, Willy library, African Journal Online (AJOL) and Google Scholar. Studies that investigated the genotypes, sub-genotypes, mixed genotypes and recombinant were included. The Z-test and regression were used for the analysis. The study protocol is registered with PROSPERO under the registration number CRD42022300220. Overall, genotype E had the highest pooled prevalence significantly higher than all the other genotypes (P < 0.001). By region, genotype A posted the highest pooled prevalence in eastern and southern Africa, E in west Africa and D in north Africa (P < 0.0001). Regarding the emerging genotypes B and C on the African continent, genotype B was significantly higher in south Africa than C (P < 0.001). In contrast, genotype C was significantly higher in east Africa than west Africa (P < 0.0001). The A1 and D/E were the most diverse sub-genotypes and genotype mixtures respectively. Finally, we observed a general progressive decrease in the prevalence of predominant genotypes but a progressive increase in the less dominant by region. Historical and recent continental and intercontinental migrations can provide a plausible explanation for the HBV genotype distribution pattern on the African continent.

Hepatitis B virus (HBV) serological patterns among the HBsAg negative hospital attendees screened for immunization.

The Hepatitis B virus (HBV) is a highly infectious virus and is endemic in Uganda. It is one of the major etiological agents for liver diseases including liver cancer. In this work, we evaluated the prevalence of the HBV serological markers and the associated socio-demographic factors among hepatitis B surface antigen (HBsAg) seronegative persons screened during routine immunization against the virus in eastern Uganda. Data on the socio-demographic characteristics were collected using a structured questionnaire, while that on the serological markers were obtained from serum samples and evaluated by using the 5-panel HBV One Step Hepatitis B Virus Combo Test Device (FastepR, HBV-P43M). The following markers were evaluated by the panel: HBsAg, HBsAb, HBcAb, and HBeAb. Data were analyzed using SPSS (version 26), and multinomial logistic regression was used to elicit the adjusted odds ratio. All the analysis were performed at a 95% confidence limit, and a P value ≤ 0.05 was considered significant. The 424 participants included in this study were mainly female (62.3%), married (55.4%) and aged 30 years and above (54.2%). The seropositivity of the HBsAb, HBeAb, HBcAb marker prevalence rates was 48(11.3%), 73(17.2%) and 45(10.6%) respectively. The majority of the participants (327, 77.1%) did not present with any marker. Married paricipants were significantly associated with reduced HBsAb seropositvity rate, whereas young people aged 18-29 years were associated the with increased odds of HBsAb seropositivity (p < 0.05). Male participants were significantly associated with the HBeAb and HBcAb seropositivity (p < 0.05). Similarly, contact with an HBV infected person was significantly associated with HBeAb and HBcAb seropositivity (p < 0.05). Further still, blood transfusion was significantly associated with the increased risk of HBcAb seropositivity (P < 0.05). This study has revealed a prevalence of HBV serological markers among the HBsAg seronegative persons in this community and an increased risk of transmission of the virus in the community. Our findings have key consequences pertaining the interventions that are pertinent in the control and prevention of the spread of the virus among apparently health persons.

Disproportionate Distribution of HBV Genotypes A and D and the Recombinant Genotype D/E in the High and Low HBV Endemic Regions of Uganda: A Wake-Up Call for Regional Specific HBV Management.

BACKGROUND: Hepatitis B virus (HBV) is the leading cause of liver-related diseases. In Uganda, there is a regional disparity in the HBV burden. Our study was aimed at establishing the circulating genotypes in a low and a high endemic region to give plausible explanations for the differences in regional burden and guide the future management of the disease. METHODS: A total of 200 HBsAg-seropositive subjects were recruited into the study by convenience sampling. The HBsAg Rapid Test Strip (Healgen Scientific Limited Liability Company, Houston, TX77047- USA) was used to screen for HBsAg while the Roche machine (Roche, Basel Switzerland/Abbot Technologies (USA)) was used to determine the viral load. The Chemistry Analyzer B120 (Mindray, China) was used for chemistry analysis. For HBV genotyping, total DNA was extracted from whole blood using the QIAamp® DNA extraction kit. Nested PCR amplification was performed using Platinum Taq DNA Polymerase (Invitrogen Corporation, USA) to amplify the 400 bp HBV polymerase gene. Purification of nested PCR products was performed using Purelink PCR product purification kit (Life Technologies, USA). Automated DNA sequencing was performed using BigDye Terminator v3.1 Cycle Sequencing Kit on 3130 Genetic Analyzer (Applied Biosystems, USA). The NCBI HBV genotyping tool (https://www.ncbi.nlm.nih.gov/projects/genotyping/formpage.cgi) was used for determination of genotype for each HBV sequence. Pearson's chi-square, multinomial logistic regression, and Mann-Whitney U tests were used for the analysis. All the analyses were done using SPSS version 26.0 and MedCalc software version 19.1.3 at 95% CI. A p < 0.05 was considered statistically significant. RESULTS: Majority of our study subjects were female (64.5%), youth (51.0%), and married (62.0%). Overall, genotype A was the most prevalent (46%). Genotype D and the recombinant genotype D/E were proportionately more distributed in the high endemic (38.2%) and low endemic (36.5%) regions, respectively. Genotype D was significantly more prevalent in the high endemic region and among the elderly (p < 0.05). Genotype D was significantly associated with elevated viral load and direct bilirubin (p < 0.05). The recombinant genotype D/E was significantly associated with elevated viral load (p < 0.05). Similarly, genotype A was significantly associated with elevated AST and GGT, lowered viral load, and normal direct bilirubin levels (p < 0.05). CONCLUSION: There is disproportionate distribution of genotypes A and D and the recombinant genotype D/E in the low and high endemic regions of Uganda. This probably could explain the differences in endemicity of HBV in our country signifying the need for regional specific HBV management and control strategies.

Prevalence and predictors of hepatitis B virus (HBV) infection in east Africa: evidence from a systematic review and meta-analysis of epidemiological studies published from 2005 to 2020.

BACKGROUND: The epidemiology of hepatitis B virus (HBV) in the general population in east Africa is not well documented. In this meta-analysis, we examined 37 full published research articles to synthesise up-to-date data on the prevalence and predictors of the HBV burden for the effective prevention and management of the virus in our region. METHODS: We examined 37 full published research articles found using PubMed, Scopus, African Journal Online (AJOL), and Google Scholar between May and October 2020. Dichotomous data on HBV prevalence and predictors of infection were extracted from the individual studies. The HBV prevalence, test of proportion, relative risk, and I2 statistics for heterogeneity were calculated using MedCalc software version 19.1.3. Begg's tests was used to test for publication bias. Sources of heterogeneity were analysed through sensitivity analysis, meta-regression, and sub-group analysis at 95% CI. P < 0.05 was considered significant for all analyses. RESULTS: The prevalence of HBV was generally high (6.025%), with publications from Kenya (8.54%), Uganda (8.454%) and those from between 2011 and 2015 (8.759%) reporting the highest prevalence (P < 0.05). Blood transfusion, scarification, promiscuity, HIV seropositivity, and being male were independent predictors significantly associated with HBV infection (P < 0.05), with the male sex being the most strongly associated predictor of HBV infection. Meta-regressions for the pooled HBV prevalence and sample size, as well as the year of publication, lacked statistical significance (P > 0.05). Omitting the study with the largest sample size slightly increased pooled HBV prevalence to 6.149%, suggesting that the studies are robust. Begg's test showed no evidence of publication bias for overall meta-analysis (p > 0.05). CONCLUSION: The burden of HBV is still high, with the male sex, blood transfusion, body scarification, and HIV seropositivity being potential predictors of infection. Thus, it is important to scale up control and prevention measures targeting persons at high risk.

Sero-prevalence of human immunodeficiency virus-hepatitis B virus (HIV-HBV) co-infection among pregnant women attending antenatal care (ANC) in sub-Saharan Africa (SSA) and the associated risk factors: a systematic review and meta-analysis.

BACKGROUND: There is plenitude of information on HIV infection among pregnant mothers attending antenatal care (ANC) in sub-Saharan Africa. However, the epidemiology of HBV-HIV co-infections in the same cohort is not clear despite the common route of transmission of both viruses. The aim of our study was to synthesize data on the prevalence of HBV-HIV co-infection among pregnant women attending ANC in Sub-Saharan Africa to assist in the design of public health interventions to mitigate the challenge. METHODS: The study was done in tandem with the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) standards and the Cochran's Q test, I2 statistics for heterogeneity and the prevalence were calculated using commercially available software called MedCalcs ( https://www.medcalc.org ). A random effect model was used to pool the prevalence since all the heterogeneities were high (≥ 78%) and Phet < 0.05 indicated significant heterogeneities. The risk factors and risk differences for HBV-HIV co-infection were analyzed. Any likely sources of heterogeneity were analyzed through sensitivity analysis, meta-regression and sub-group analysis. All analyses were done at 95% level of significance and a P < 0.05 was considered significant. RESULTS: The overall pooled prevalence of HBV-HIV co-infection among pregnant mothers in sub-Saharan Africa was low 3.302% (95%CI = 2.285 to 4.4498%) with heterogeneities (I2) of 97.59% (P > 0.0001). Within regional sub group meta-analyses, West Africa had significantly higher prevalence of 5.155% (95% = 2.671 to 8.392%) with heterogeneity (I2) of 92.25% (P < 0.0001) than any other region (P < 0.001). Articles published from 2004-2010 had significantly higher prevalence of 6.356% (95% = 3.611 to 9.811%) with heterogeneity (I2) 91.15% (P < 0.0001) compared to those published from 2011 to 2019 (P < 0.001). The HIV positive cohort had significantly higher prevalence of HBV-HIV co-infection of 8.312% (95% CI = 5.806 to 11.22%) with heterogeneity (I2)94.90% (P < 0.0001) than the mothers sampled from the general population with a prevalence of 2.152% (95% CI = 1.358 to 3.125%) (P < 0.001). The overall and sub group analyses had high heterogeneities (I2 > 89%, P < 0.0001) but was reduced for South Africa (I2) = 78.4% (P = 0.0314). Age, marital status and employment were independent factors significantly associated with risk of HBV-HIV co-infection (P < 0.001) but not extent of gravidity and education level (P > 0.05). After meta-regression for year of publication and sample size for HBsAg positivity, the results were not significantly associated with HBV pooled prevalence for sample size (P = 0.146) and year of publication (P = 0.560). Following sensitivity analysis, the HBsAg pooled prevalence slightly increased to 3.429% (95% CI = 2.459 to 4.554%) with heterogeneity I2 = 96.59% (95% CI = 95.93 to 97.14%), P < 0.0001 CONCLUSION: There is an urgent need for routine HBV screening among HIV positive pregnant mothers attending antenatal care in sub-Saharan Africa to establish the extent of HBV-HIV co-infection in this cohort. Future studies need to investigate the putative risk factors for HBV-HIV co-infection and prioritize plausible control strategies.

Performance evaluation of a prototype rapid diagnostic test for combined detection of gambiense human African trypanosomiasis and malaria.

BACKGROUND: Malaria is endemic in all regions where gambiense or rhodesiense human African trypanosomiasis (HAT) is reported, and both diseases have similarities in their symptomatology. A combined test could be useful for both diseases and would facilitate integration of the screening for gambiense HAT (gHAT) and malaria diagnosis. This study aimed to evaluate a combined prototype rapid diagnostic test (RDT) for gHAT and malaria. METHODS: Blood samples were collected in the Democratic Republic of the Congo and in Uganda to evaluate the performance of a prototype HAT/Malaria Combined RDT in comparison to an individual malaria RDT based on Plasmodium falciparum (P.f.) Histidine Rich Protein II (HRP-II or HRP2) antigen (SD BIOLINE Malaria Ag P.f. RDT) for malaria detection and an individual gHAT RDT based on recombinant antigens, the SD BIOLINE HAT 2.0 RDT for HAT screening. Due to the current low prevalence of gHAT in endemic regions, the set of blood samples that were collected was used to evaluate the specificity of the RDTs for gHAT, and additional archived plasma samples were used to complete the evaluation of the HAT/Malaria Combined RDT in comparison to the HAT 2.0 RDT. RESULTS: Frozen whole blood samples from a total of 486 malaria cases and 239 non-malaria controls, as well as archived plasma samples from 246 gHAT positive and 246 gHAT negative individuals were tested. For malaria, the sensitivity and specificity of the malaria band in the HAT/Malaria Combined RDT were 96.9% (95% CI: 95.0-98.3) and 97.1% (95% CI: 94.1-98.8) respectively. The sensitivity and specificity of the SD BIOLINE malaria Ag P.f. RDT were 97.3% (95% CI: 95.5-98.6) and 97.1% (95% CI: 94.1-98.8) respectively. For gHAT, using archived plasma samples, the sensitivity and specificity were respectively 89% (95% CI: 84.4-92.6) and 93.5% (95% CI: 89.7-96.2) with the HAT/Malaria Combined RDT, and 88.2% (95% CI: 83.5-92) and 94.7% (95% CI: 91.1-97.2) with the HAT 2.0 RDT. Using the whole blood samples that were collected during the study, the specificity of the HAT/Malaria Combined RDT for gHAT was 95.8% (95% CI: 94.3-97.0). CONCLUSION: The HAT/Malaria Combined prototype RDT was as accurate as the individual malaria or gHAT RDTs. The HAT/Malaria Combined prototype RDT is therefore suitable for both malaria diagnosis and gHAT screening. However, there is a need to assess its accuracy using fresh samples in prospective clinical trials.

Consolidating HIV testing in a public health laboratory for efficient and sustainable early infant diagnosis (EID) in Uganda.

Uganda introduced an HIV Early Infant Diagnosis (EID) program in 2006, and then worked to improve the laboratory, transportation, and clinical elements. Reported here are the activities involved in setting up a prospective analysis in which the Ministry of Health, with its NGO partners, determined it would be more effective and efficient to consolidate the initial eight-laboratory system for EID testing of HIV dried blood samples offered by two nongovernmental partners operating research facilities into a single well-equipped and staffed laboratory within the Ministry. A retrospective analysis confirmed that redesign reduced overhead cost per PCR test of HIV dried blood samples from US$22.20 to an average of $5. Along with the revamped system of sample collection, transportation, and result communication, Uganda has been able to vastly increase the HIV diagnosis of babies and engagement of them and their mothers in clinical care, including antiretroviral therapy. Uganda reduced turnaround times for results reporting to clinicians from more than a month in 2006 to just 2 weeks by 2014, even as samples tested increased dramatically. The next challenge is overcoming loss of babies and mothers to follow up.

Uganda's new national laboratory sample transport system: a successful model for improving access to diagnostic services for Early Infant HIV Diagnosis and other programs.

INTRODUCTION: Uganda scaled-up Early HIV Infant Diagnosis (EID) when simplified methods for testing of infants using dried blood spots (DBS) were adopted in 2006 and sample transport and management was therefore made feasible in rural settings. Before this time only 35% of the facilities that were providing EID services were reached through the national postal courier system, Posta Uganda. The transportation of samples during this scale-up, therefore, quickly became a challenge and varied from facility to facility as different methods were used to transport the samples. This study evaluates a novel specimen transport network system for EID testing. METHODS: A retrospective study was done in mid-2012 on 19 pilot hubs serving 616 health facilities in Uganda. The effect on sample-result turnaround time (TAT) and the cost of DBS sample transport on 876 sample-results was analyzed. RESULTS: The HUB network system provided increased access to EID services ranging from 36% to 51%, drastically reduced transportation costs by 62%, reduced turn-around times by 46.9% and by a further 46.2% through introduction of SMS printers. CONCLUSIONS: The HUB model provides a functional, reliable and efficient national referral network against which other health system strengthening initiatives can be built to increase access to critical diagnostic and treatment monitoring services, improve the quality of laboratory and diagnostic services, with reduced turn-around times and improved quality of prevention and treatment programs thereby reducing long-term costs.

The good, the bad, and the unknown: quality of clinical laboratories in Kampala, Uganda.

BACKGROUND: Clinical laboratories are crucial in addressing the high rates of communicable and non-communicable diseases seen in sub-Saharan Africa (SSA). However, the most basic information, such as the number and quality of clinical laboratories in SSA, is not available. The objective of this study was to create a practical method for obtaining this information in SSA towns and cities using an initial survey in Kampala, Uganda. METHODS: Kampala city was divided into 5 partially-overlapping regions. Each region was assigned to 2-3 surveyors who identified and surveyed laboratories in their respective regions; in person and on foot. A modified version of the World Health Organization - African Region (WHO/AFRO) Laboratory Strengthening Checklist was used to obtain baseline measures of quality for all clinical laboratories within Kampala city. The surveyors also measured other attributes of each laboratory, such as their affiliation (government, private etc), designation (national hospital, district hospital, standalone etc), staff numbers, and type of staff. RESULTS: The survey team identified and surveyed 954 laboratories in Kampala city. 96% of laboratories were private. Only 45 (5%) of the laboratories met or surpassed the lowest quality standards defined by the WHO/AFRO-derived laboratory strengthening tool (1-star). These 45 higher-quality laboratories were, on average, larger and had a higher number of laboratory-specific staff (technologists, phlebotomists etc) than the other 909 laboratories. 688 (72%) of the 954 laboratories were not registered with the Ministry of Health (MoH). CONCLUSIONS: This comprehensive evaluation of the number, scope, and quality of clinical laboratories in Kampala is the first published survey of its kind in sub-Saharan Africa. The survey findings demonstrated that laboratories in Kampala that had qualified personnel and those that had higher testing volumes, tended to be of higher-quality.

Virologic versus immunologic monitoring and the rate of accumulated genotypic resistance to first-line antiretroviral drugs in Uganda.

BACKGROUND: Viral load monitoring (VLM) to identify individuals failing antiretroviral therapy (ART) is not widely available in resource-limited settings. We compared the genotypic resistance patterns between clients with VLM versus immunological monitoring (IM). METHODS: Between 2004-2008, 559 ART naïve clients were enrolled in a prospective cohort, initiated on ART, and monitored with viral load (VL) and CD4+ cell counts every 6 months (VLM group). From February 2008 through June 2009, 998 clients on ART for 36-40 months (corresponding to the follow-up time of the VLM group) at the same clinic and monitored with CD4+ cell counts every 6 months were recruited into a cross sectional study (IM group). Samples from VLM clients at 12, 24 and 36 months and IM clients at 36-40 months with VL > 2000 copies/ml underwent genotypic drug resistance testing. RESULTS: Baseline characteristics were similar. Virologic failure (VL > 400 copies/ml) at 12, 24 and 36 months in the VLM group were 12%, 6% and 8% respectively, and in the IM group 10% at 36-40 months. Samples from 39 VLM and 70 IM clients were genotyped. 23/39 (59%) clients in the VLM group (at 12, 24 or 36 months) compared to 63/70 (90%) in the IM group, (P < 0.0001) had at least 1 non-nucleoside reverse transcriptase mutation. 19/39 (49%) of VLM clients had an M184V mutation compared to 61/70 (87%) in the IM group (P < 0.0001). Only 2/39 (5%) of VLM clients developed thymidine analogue mutations compared to 34/70 (49%) of IM clients (P < 0.0001). CONCLUSIONS: Routine VL monitoring reduced the rate of accumulated genotypic resistance to commonly used ART in Uganda.

Detecting adenosine triphosphatase 6 (pfATP6) point mutations that may be associated with Plasmodium falciparum resistance to artemisinin: prevalence at baseline, before policy change in Uganda.

The artemisinin based combination therapy (ACT) of artemether and lumefantrine (Co-artem) has recently replaced chloroquine and fansidar as the first line treatment policy drug in Uganda. It is necessary to develop practical procedures to monitor the likely emergence and spread of artemisinin resistant P. falciparum strains. We have analyzed the genotypes of PfATP6 in parasites from 300 stored filter paper samples from malaria patients who were diagnosed and treated in the years 1999 to 2004 at three field sites in Uganda. This is a period just prior to introduction of Co-artem. In order to develop a simple molecular procedure for mutation detection, regions of PfATP6 encoding protein domains important in artemisinin binding was amplified by nested PCR. Three DNA products, which together contain most of the coding region of amino acids located within the putative active site of pfATP6 were readily amplified. The amplified DNA was digested by restriction enzymes and the fragments sized by agarose gel electrophoresis. For the important codons 260, 263 and 769, methods using engineered restriction sites were employed. We did not find mutations at codons for the key residues Lys 260, Leu263, Gln266, Ser769 and Asn1039. Nucleotide sequencing of pfATPase6 gene DNA from at least 15 clinical isolates confirmed the above findings and suggested that mutations at these amino acid residues have not emerged in our study sites.

Improving quality management systems of laboratories in developing countries: an innovative training approach to accelerate laboratory accreditation.

The Strengthening Laboratory Management Toward Accreditation (SLMTA) program was developed to promote immediate, measurable improvement in laboratories of developing countries. The laboratory management framework, a tool that prescribes managerial job tasks, forms the basis of the hands-on, activity-based curriculum. SLMTA is implemented through multiple workshops with intervening site visits to support improvement projects. To evaluate the effectiveness of SLMTA, the laboratory accreditation checklist was developed and subsequently adopted by the World Health Organization Regional Office for Africa (WHO AFRO). The SLMTA program and the implementation model were validated through a pilot in Uganda. SLMTA yielded observable, measurable results in the laboratories and improved patient flow and turnaround time in a laboratory simulation. The laboratory staff members were empowered to improve their own laboratories by using existing resources, communicate with clinicians and hospital administrators, and advocate for system strengthening. The SLMTA program supports laboratories by improving management and building preparedness for accreditation.

The challenge of HIV-1 antiretroviral resistance in Africa in the era of HAART.

Antiretroviral therapy programs in Africa are currently providing treatment for almost two million people. The long-term success of large scale antiretroviral therapy programs in sub-Saharan Africa remains uncertain because of the limited information currently available on rates of virologic failure and selection for drug-resistant variants in the different HIV subtypes. This article provides a comprehensive review of the published literature on the prevalence of primary and secondary HIV drug resistance with different subtypes and in various settings across sub-Saharan Africa.

Cotrimoxazole resistance of Streptococcus pneumoniae and commensal streptococci from Kampala, Uganda.

Trimethoprim sulfamethoxazole (cotrimoxazole, CTX) is used frequently as part of standard medical care for people living with HIV/AIDS in Africa. The mechanisms of resistance to sulfonamides and trimethoprim in commensal streptococci from Uganda were determined and compared to S. pneumoniae. Commensal streptococci showing high-level resistance to cotrimoxazole were cultured and analysed for species identity and polymorphisms in the genes coding for dihydropteroate synthase (DHPS) and dihydrofolate reductase (DHFR). Seven isolates of S. pneumoniae from blood and cerebrospinal fluid (CSF) were similarly examined. There was considerable polymorphism in both DHPS and DHFR. In DHFR, the mutations E20D and I100L were present in all sequenced isolates. Other mutations such as L135F, and different substitutions in D92, were frequent. The most common DHPS variants had 2 serine residues added after amino acid 60, or arginine and proline added after amino acid 59. In addition, 3 new insertions/substitutions were found. There were no obvious differences between the mutation patterns in S. pneumoniae and commensal streptococci, suggesting that the chromosomal mutations have been spread by transformational interchanges of DNA among related organisms.

Rapid increase in resistance of Plasmodium falciparum to chloroquine-Fansidar in Uganda and the potential of amodiaquine-Fansidar as a better alternative.

Combinations of chloroquine (CQ) and sulfadoxine-pyrimethamine (SP) [CQSP] as the first line agents in Uganda have replaced CQ monotherapy. The idea of the combination is to delay the development of malaria resistance to either drug when used alone. We compared the clinical, parasitological and molecular findings of two studies with treatment arms of CQSP, amodiaquine (AQ) plus SP (AQSP) both done in 2003 with a study done 1 year earlier (2002) using SP alone. There was a notable decrease in adequate clinical response (ACR) by day 14 from 92.7% with SP to 80% with the combination CQSP, a year later. AQSP combination was found to have the best effect (94.3% ACR). There were no early treatment failures in the AQSP group. However, treatment failures were recorded at 20% on day 14 and 43% on day 28 for CQSP treatment and 5.7% by day 14 and 28.8% by day 28 in the AQSP group. The number of mutations that are associated with SP resistance increased from 2002 to 2003 at all loci monitored, from 83.8 to 100% at codon 108, 58.7 to 76% at codon 59 in the DHFR gene, and from 58.8 to 86% at codon 437 and 33 to 43% at codon 540 in the DHPS gene. We conclude that there has been a rapid development of resistance since the introduction of the new policy guidelines. AQSP was found to be a superior drug combination compared to CQSP and could be used as a low cost alternative at the moment.

Plasmodium falciparum: higher incidence of molecular resistance markers for sulphadoxine than for pyrimethamine in Kasangati, Uganda.

In November of 2000, Uganda changed its anti-malarial policy to replace chloroquine (CQ) with a combination of CQ and sulphadoxine-pyrimethamine (SP) as the first line agents. Information was limited on the efficacy of either drug. The present study was designed to provide baseline information on the efficacy of SP and the prevalence of molecular markers that are associated with SP resistance. Blood samples were collected on filter paper from 169 consenting patients who were diagnosed with malaria. Patients were treated with SP and followed for 14 days using the WHO clinical guidelines. The samples were analysed for molecular resistance markers and correlation of the molecular markers with clinical findings was assessed. SP monotherapy was efficacious for 140 of 163 (85.9%) treated patients. We found a high level of mutations in alleles which have previously been reported to be associated with SP resistance, but there was no correlation between clinical outcomes and molecular markers. With the exception of codon S108 in dhfr (dhfr S108N was at 94.9%), frequencies of dihydropteroate synthase (dhps) mutant and mixed alleles combined (A437G 89% and K540E 83.9%) were higher than those of dihydrofolate reductase (dhfr) (N51I 58.4%, C59R 31.3%).

Relationship between age, molecular markers, and response to sulphadoxine-pyrimethamine treatment in Kampala, Uganda.

Sulphadoxine/pyrimethamine (SP) has become the first-line treatment of uncomplicated malaria in a number of African countries. Molecular surveillance of resistance-mediating mutations in Plasmodium falciparum dihydrofolate reductase (dhfr) and dihydropteroate synthase (dhps) has been proposed as a means of predicting SP treatment outcomes, but optimal methods of surveillance in different populations have not been well established. To investigate the relationship between molecular markers of SP resistance, host immunity, and response to therapy, we evaluated the association between the presence of five key dhfr and dhps mutations at enrollment and clinical outcome in children and adults treated with SP for uncomplicated malaria in Kampala, Uganda. Clinical treatment failure was 11% at 14 days, increasing to 30% at 28 days, after excluding new infections. Outcomes varied markedly based on the number of dhfr and dhps mutations and on the age of treated subjects. All infections with less than two dhfr/dhps mutations were successfully treated. Treatment failure associated with any two, three, or four dhfr/dhps mutations occurred in nine of 24 (38%) children up to 5 years, but not in older patients (0/20). In the presence of all five mutations, treatment failure occurred equally in children aged 5 years or younger [7/16 (44%)] and in older patients [8/16 (50%)]. Our results showed that age, a surrogate marker of antimalarial immunity, had a major impact on the relationship between polymorphisms in SP target enzymes and treatment outcomes. The use of molecular markers of SP resistance to predict treatment failure rates should take age into account.