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The application of very fast image detectors to the fine tracking system of free space optical (FSO) communication has been demonstrated in several projects. In the near surface of the earth, the influence of the atmosphere on the optical communication system must be considered. The optical communication system must be designed to be able to suppress the influence of atmospheric turbulence. The authors have used the high-speed CMOS image sensor for the fine tracking system of 15 km FSO communication demonstration. In this study, the authors present the atmospheric influence on the fine tracking detector, and find out the tracking algorithm for the fine tracking detector to detect the centre of the received spot. On analysis of atmosphere turbulence influenced and the experiment data, the authors find that using centroid algorithm in the fine tracking system is better than the centre of mass algorithm. They proposed a new centroid algorithm in the fine tracking system and use this algorithm in the demonstration system. They found it can minimise the atmosphere turbulence influence. [ABSTRACT FROM AUTHOR]

The transmission of a free-space optical (FSO) beam through the atmosphere is influenced by several factors: chief among them are weather conditions such as fog, rain, and snow. In the design of FSO communication systems, it is necessary to determine the weather dependence of the system and derive a relation between the weather parameters and performance of the FSO communication systems. From our experiments, we have established that the link-operating rate, which is an important parameter for overall FSO-communication-system performance, cannot be estimated using the cumulative-distribution probability of the visibility data. A technique of estimating short-term FSO-link performance characteristics is required. Using this approach, a method for approximating an FSO link-operating rate is proposed for the western Kanto area in Japan, where the link-performance deterioration is mostly a result of rain. The method is based on the analysis of short-term recorded rain intensity and visibility data. The estimated FSO link-operating rate is shown to have a good conformance with the experimental measured result. [ABSTRACT FROM PUBLISHER]

Social network strategy (SNS) testing uses network connections to refer individuals at high risk to HIV testing services (HTS). In Tanzania, SNS testing is offered in communities and health facilities. In communities, SNS testing targets key and vulnerable populations (KVP), while in health facilities it complements index testing by reaching unelicited index contacts. Routine data were used to assess performance and trends over time in PEPFAR-supported sites between October 2021 and March 2023. Key indicators included SNS social contacts tested, and new HIV-positives individuals identified. Descriptive and statistical analysis were conducted. Univariable and multivariable analysis were applied, and variables with P -values <0.2 at univariable analysis were considered for multivariable analysis. Overall, 121,739 SNS contacts were tested, and 7731 (6.4%) previously undiagnosed individuals living with HIV were identified. Tested contacts and identified HIV-positives were mostly aged ≥15 years (>99.7%) and females (80.6% of tests, 79.4% of HIV-positives). Most SNS contacts were tested (78,363; 64.7%) and diagnosed (6376; 82.5%) in communities. SNS tests and HIV-positives grew 11.5 and 6.1-fold respectively, from October-December 2021 to January-March 2023, with majority of clients reached in communities vs. facilities (78,763 vs. 42,976). These results indicate that SNS testing is a promising HIV case-finding approach in Tanzania.

Background: There is limited evidence on COVID-19 vaccination uptake among people living with HIV (PLHIV) and health care workers (HCWs), with the current evidence concentrated in high-income countries. There is also limited documentation in the published literature regarding the feasibility and lessons from implementing targeted vaccination strategies to reach PLHIV and HCWs in low- and middle-income countries., Program Development, Piloting, and Implementation: We designed and implemented multifaceted strategies to scale up targeted COVID-19 vaccination among PLHIV and HCWs in 11 administrative regions on the mainland of Tanzania plus Zanzibar. An initial 6-week intensification strategy was implemented using a diverse partnership model comprising key stakeholders at the national- and subnational levels. A layered package of strategies included expanding the number of certified vaccinators, creating vaccination points within HIV clinics, engaging HCWs to address their concerns, and building the capacity of HCWs as "champions" to promote and facilitate vaccination. We then closely monitored COVID-19 vaccination uptake in 562 high-volume HIV clinics. Between September 2021 and September 2022, the proportion of fully vaccinated adult PLHIV increased from <1% to 97% and fully vaccinated HCWs increased from 23% to 80%., Lessons and Implications: Our intra-action review highlighted the importance of leveraging a strong foundation of existing partnerships and platforms, integrating COVID-19 vaccination points within HIV clinics, and refining strategies to increase vaccination demand while ensuring continuity of vaccine supply to meet the increased demand. Lessons from Tanzania can inform targeted vaccination of vulnerable groups in future health emergencies., (© Jalloh et al.)

Effective services along the HIV continuum of care from HIV testing and counseling to linkage, and from linkage to antiretroviral therapy (ART) initiation and retention, are key to improved health outcomes of persons living with HIV. A comprehensive analysis of the costs and outcomes of cascade services is needed to help allocate and prioritize resources to achieve UNAIDS targets. We evaluated the costs and population-level impact of a community-wide, integrated scale-up of testing, linkage, and defaulter-tracing programs implemented in Bukoba Municipal Council, Tanzania. Costs per identified HIV-positive client for provider-initiated, and home- and venue-based testing and counseling were $92.64 United States dollars (USD), $256.33 USD, and $281.57 USD, respectively. Costs per patient linked to HIV care and ART were $47.69 USD and $74.12 USD, respectively, during all ART-eligibility periods combined. Costs per defaulter traced and returned to HIV care were $47.56 USD and $206.77 USD, respectively. The provider-initiated testing and counseling was the most cost-effective modality. Testing approaches targeted to populations groups and geographic location with high testing positivity rates may improve the overall efficiency of testing services. The expansion of ART eligibility criteria and high linkage rate also result in efficiency gains and economies of scale of linkage services.

Beginning in March 2020, to reduce COVID-19 transmission, the US President's Emergency Plan for AIDS Relief supporting voluntary medical male circumcision (VMMC) services was delayed in 15 sub-Saharan African countries. We reviewed performance indicators to compare the number of VMMCs performed in 2020 with those performed in previous years. In all countries, the annual number of VMMCs performed decreased 32.5% (from 3,898,960 in 2019 to 2,631,951 in 2020). That reduction is largely attributed to national and local COVID-19 mitigation measures instituted by ministries of health. Overall, 66.7% of the VMMC global annual target was met in 2020, compared with 102.0% in 2019. Countries were not uniformly affected; South Africa achieved only 30.7% of its annual target in 2020, but Rwanda achieved 123.0%. Continued disruption to the VMMC program may lead to reduced circumcision coverage and potentially increased HIV-susceptible populations. Strategies for modifying VMMC services provide lessons for adapting healthcare systems during a global pandemic.

The coronavirus disease pandemic has highlighted the need to establish and maintain strong infection prevention and control (IPC) practices, not only to prevent healthcare-associated transmission of SARS-CoV-2 to healthcare workers and patients but also to prevent disruptions of essential healthcare services. In East Africa, where basic IPC capacity in healthcare facilities is limited, the US Centers for Disease Control and Prevention (CDC) supported rapid IPC capacity building in healthcare facilities in 4 target countries: Tanzania, Ethiopia, Kenya, and Uganda. CDC supported IPC capacity-building initiatives at the healthcare facility and national levels according to each country's specific needs, priorities, available resources, and existing IPC capacity and systems. In addition, CDC established a multicountry learning network to strengthen hospital level IPC, with an emphasis on peer-to-peer learning. We present an overview of the key strategies used to strengthen IPC in these countries and lessons learned from implementation.

Background: Community randomised trials have had mixed success in implementing combination prevention strategies that diagnose 90% of people living with HIV, initiate and retain on antiretroviral therapy (ART) 90% of those diagnosed, and achieve viral load suppression in 90% of those on ART (90-90-90). The Bukoba Combination Prevention Evaluation (BCPE) aimed to achieve 90-90-90 in Bukoba Municipal Council, Tanzania, by scaling up new HIV testing, linkage, and retention interventions., Method: We did population-based, cross-sectional surveys before and after our community-wide intervention in Bukoba-a mixed urban and rural council of approximately 150 000 residents located on the western shore of Lake Victoria in Tanzania. BCPE interventions were implemented in 11 government-supported health-care facilities throughout Bukoba from Oct 1, 2014, to March 31, 2017, when national ART-eligibility guidelines expanded from CD4 counts of less than 350 cells per μL (Oct 1, 2014-Dec 31, 2015) and 500 or less cells per μL (Jan 1, 2016-Sept 30, 2016) to any CD4 cell count (test and treat, Oct 1, 2016-March 31, 2017). We used pre-intervention (Nov 4, 2013-Jan 25, 2014) and post-intervention (June 21, 2017-Sept 20, 2017) population-based household surveys to assess population prevalence of undiagnosed HIV infection and ART coverage, and progress towards 90-90-90, among residents aged 18-49 years., Findings: During the 2·5-year intervention, BCPE did 133 695 HIV tests, diagnosed and linked 3918 people living with HIV to HIV care at 11 Bukoba facilities, and returned to HIV care 604 patients who had stopped care. 4795 and 5067 residents aged 18-49 years participated in pre-intervention and post-intervention surveys. HIV prevalence before and after the intervention was similar: pre-intervention 8·9% (95% CI 7·5-10·4); post-intervention 8·4% (6·9-9·9). Prevalence of undiagnosed HIV infection decreased from 4·7% to 2·0% (prevalence ratio 0·42, 95% CI 0·31-0·57), and current ART use among all people living with HIV increased from 32·2% to 70·9% (2·20, 1·82-2·66) overall, 23·0% to 62·1% among men (2·70, 1·84-3·96), and 16·7% to 64·4% among people aged 18-29 years (3·87, 2·54-5·89). Of 436 and 435 people living with HIV aged 18-49 years who participated in pre-intervention and post-intervention surveys, previous HIV diagnosis increased from 47·4% (41·3-53·4) to 76·2% (71·8-80·6), ART use among diagnosed people living with HIV increased from 68·0% (60·9-75·2) to 93·1% (90·2-96·0), and viral load suppression of those on ART increased from 88·7% (83·6-93·8) to 91·3% (88·6-94·1)., Interpretation: BCPE findings suggest scaling up recommended HIV testing, linkage, and retention interventions can help reduce prevalence of undiagnosed HIV infection, increase ART use among all people living with HIV, and make substantial progress towards achieving 90-90-90 in a relatively short period. BCPE facility-based testing and linkage interventions are undergoing national scale up to help achieve 90-90-90 in Tanzania., Funding: US Presidents' Emergency Plan for AIDS Relief., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Reducing HIV-related morbidity and mortality, and effectively eliminating HIV transmission risk, depends on use of antiretroviral therapy (ART) to achieve and maintain viral load suppression (VLS)* (1,2). By 2020, sub-Saharan African countries are working to achieve VLS among 90% of persons using ART and 73% of all persons living with HIV infection (1). In Tanzania, a country with 1.4 million persons with HIV infection, 49.6% of HIV-positive persons aged 15-49 years had achieved VLS in 2017, including only 21.5% of men and 44.6% of women aged 25-29 years (3). To identify interventions that might increase VLS in Tanzania, and reduce VLS-associated sex and age-group disparities, the Bukoba Combination Prevention Evaluation (BCPE) scaled up new HIV testing, linkage to care, and retention on ART interventions throughout Bukoba Municipal Council (Bukoba), Tanzania, during October 2014-March 2017 (4,5). Located on the western shore of Lake Victoria, Bukoba is a mixed urban and rural municipality of 150,000 persons and capital of Kagera Region. Of the 31 regions of Tanzania, Kagera has the fourth highest prevalence of HIV infection (6.8%) among residents aged 15-49 years (3). CDC analyzed data from BCPE preintervention and postintervention surveys and found that VLS prevalence among HIV-positive Bukoba residents aged 18-49 years increased approximately twofold overall (from 28.6% to 64.8%) and among women (33.3% to 67.8%) and approximately threefold among men (20.5% to 59.1%) and young adults aged 18-29 years (15.6% to 56.7%). During 2017, BCPE facility-based testing and linkage interventions were approved as new service delivery models by the Tanzania Ministry of Health, Community Development, Gender, Elderly and Children (4,5). After a successful rollout to 208 facilities in 11 regions in 2018, BCPE interventions are being scaled up in all regions of Tanzania in 2019 with support from the United States President's Emergency Plan for AIDS Relief (PEPFAR). † ., Competing Interests: All authors have completed and submitted the ICMJE form for disclosure of potential conflicts of interest. No potential conflicts of interest were disclosed.

To diagnose ≥90% HIV-infected residents (diagnostic coverage), the Bukoba Combination Prevention Evaluation (BCPE) implemented provider-initiated (PITC), home- (HBHTC), and venue-based (VBHTC) HIV testing and counseling (HTC) intervention in Bukoba Municipal Council, a mixed urban and rural lake zone community of 150,000 residents in Tanzania. This paper describes the methods, outcomes, and incremental costs of these HTC interventions. PITC was implemented in outpatient department clinics in all eight public and three faith-based health facilities. In clinics, lay counselors routinely screened and referred eligible patients for HIV testing conducted by HTC-dedicated healthcare workers. In all 14 wards, community teams offered HTC to eligible persons encountered at 31,293 home visits and at 79 male- and youth-frequented venues. HTC was recommended for persons who were not in HIV care or had not tested in the prior 90 days. BCPE conducted 133,695 HIV tests during the 2.5 year intervention (PITC: 88,813, 66%; HBHTC: 27,407, 21%; VBHTC: 17,475, 13%). Compared with other strategies, PITC conducted proportionally more tests among females (65%), and VBHTC conducted proportionally more tests among males (69%) and young-adults aged 15-24 years (42%). Of 5,550 (4.2% of all tests) HIV-positive tests, 4,143 (75%) clients were newly HIV diagnosed, including 1,583 males and 881 young adults aged 15-24 years. Of HIV tests conducted 3.7%, 1.8%, and 2.1% of PITC, HBHTC, and VBHTC clients, respectively, were newly HIV diagnosed; PITC accounted for 79% of all new diagnoses. Cost per test (per new diagnosis) was $4.55 ($123.66), $6.45 ($354.44), and $7.98 ($372.67) for PITC, HBHTC, and VBHTC, respectively. In a task-shifting analysis in which lay counselors replaced healthcare workers, estimated costs per test (per new diagnosis) would have been $3.06 ($83.15), $ 4.81 ($264.04), and $5.45 ($254.52), for PITC, HBHTC, and VBHTC, respectively. BCPE models reached different target groups, including men and young adults, two groups with consistently low coverage. Implementation of multiple models is likely necessary to achieve ≥90% diagnostic coverage., Competing Interests: Author Johnita Byrd is employed by ICF International. ICF International was contracted by the U.S. Centers for Disease Control and Prevention to provide data management services only. There are no patents, products in development or marketed products to declare. This does not alter the authors’ adherence to all the PLOS ONE policies on sharing data and materials.

Although several studies have evaluated one or more linkage services to improve early enrollment in HIV care in Tanzania, none have evaluated the package of linkage services recommended by the Centers for Disease Control and Prevention (CDC) and the World Health Organization (WHO). We describe the uptake of each component of the CDC/WHO recommended package of linkage services, and early enrollment in HIV care and antiretroviral therapy (ART) initiation among persons with HIV who participated in a peer-delivered, linkage case management (LCM) program implemented in Bukoba, Tanzania, October 2014 -May 2017. Of 4206 participants (88% newly HIV diagnosed), most received recommended services including counseling on the importance of early enrollment in care and ART (100%); escort by foot or car to an HIV care and treatment clinic (CTC) (83%); treatment navigation at a CTC (94%); telephone support and appointment reminders (77% among clients with cellphones); and counseling on HIV-status disclosure and partner/family testing (77%), and on barriers to care (69%). During three periods with different ART-eligibility thresholds [CD4<350 (Oct 2014 -Dec 2015, n = 2233), CD4≤500 (Jan 2016 -Sept 2016, n = 1221), and Test & Start (Oct 2016 -May 2017, n = 752)], 90%, 96%, and 97% of clients enrolled in HIV care, and 47%, 67%, and 86% of clients initiated ART, respectively, within three months of diagnosis. Of 463 LCM clients who participated in the last three months of the rollout of Test & Start, 91% initiated ART. Estimated per-client cost was $44 United States dollars (USD) for delivering LCM services in communities and facilities overall, and $18 USD for a facility-only model with task shifting. Well accepted by persons with HIV, peer-delivered LCM services recommended by CDC and WHO can achieve near universal early ART initiation in the Test & Start era at modest cost and should be considered for implementation in facilities and communities experiencing <90% early enrollment in ART care., Competing Interests: Author Johnita Byrd is employed by ICF International. ICF International was contracted by CDC to provide data-management services only. There are no patents, products in development or marketed products to declare. This does not alter the authors’ adherence to all the PLOS ONE policies on sharing data and materials.

Countries in Southern and Eastern Africa have the highest prevalence of human immunodeficiency virus (HIV) infection in the world; in 2015, 52% (approximately 19 million) of all persons living with HIV infection resided in these two regions.* Voluntary medical male circumcision (VMMC) reduces the risk for heterosexually acquired HIV infection among males by approximately 60% (1). As such, it is an essential component of the Joint United Nations Programme on HIV/AIDS (UNAIDS) strategy for ending acquired immunodeficiency syndrome (AIDS) by 2030 (2). Substantial progress toward achieving VMMC targets has been made in the 10 years since the World Health Organization (WHO) and UNAIDS recommended scale-up of VMMC for HIV prevention in 14 Southern and Eastern African countries with generalized HIV epidemics and low male circumcision prevalence (3). † This has been enabled in part by nearly $2 billion in cumulative funding through the President's Emergency Plan for AIDS Relief (PEPFAR), administered through multiple U.S. governmental agencies, including CDC, which has supported nearly half of all PEPFAR-supported VMMCs to date. Approximately 14.5 million VMMCs were performed globally during 2008-2016, which represented 70% of the original target of 20.8 million VMMCs in males aged 15-49 years through 2016 (4). Despite falling short of the target, these VMMCs are projected to avert 500,000 HIV infections by the end of 2030 (4). However, UNAIDS has estimated an additional 27 million VMMCs need to be performed by 2021 to meet the Fast Track targets (2). This report updates a previous report covering the period 2010-2012, when VMMC implementing partners supported by CDC performed approximately 1 million VMMCs in nine countries (5). During 2013-2016, these implementing partners performed nearly 5 million VMMCs in 12 countries. Meeting the global target will require redoubling current efforts and introducing novel strategies that increase demand among subgroups of males who have historically been reluctant to undergo VMMC.

Background: In sub-Saharan Africa, blood-borne pathogens exposure (BPE) is a serious risk to healthcare workers (HCW)., Methods: We conducted a cross-sectional study assessing BPE among HCW at three public hospitals in Tanzania. From August to November 2012, HCW were surveyed using Audio-Computer Assisted Self-Interview. All HCW at risk for BPE were invited to participate. Factors associated with reporting BPE were identified using logistic regression., Findings: Of the 1102 eligible HCW, 973 (88%) completed the survey. Of these, 690 (71%) were women and 499 (52%) were nurses and nurse assistants. Of the 357 HCW who had a BPE (32%) in the previous 6 months, 120 (34%) reported it. Among these 120 reported exposures, 93 (78%) HCWs reported within 2 h of exposure, 98 (82%) received pre- and post-HIV test counselling, and 70 (58%) were offered post-exposure prophylaxis (PEP). Independent factors associated with reporting BPE were being female (adjusted odds ratio [AOR], 2.0; 95% confidence interval [CI], 1.2-3.5), having ever-received BPE training (AOR, 2.0; 95% CI, 1.2-3.5), knowledge that HCW receive PEP at another facility (AOR, 2.6; 95% CI, 1.5-4.4), low/no perceived risk related to BPE (AOR, 4.2; 95% CI, 1.9-9.4) and HIV testing within the past year (AOR, 2.3; 95% CI, 1.2-4.4)., Conclusion: These results highlight the importance of appropriate training on the prevention and reporting of occupational exposure to increase acceptance of HIV testing and improve access to PEP after BPE., Competing Interests: Declaration of conflicting interests: The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

In this paper, we present an experimental study on transmission of RF signals over turbulent free-space optics (FSO) channel by using off-the-shelf Radio Frequency - FSO (RF-FSO) antennas. The results demonstrate potential of utilizing FSO links for transmission of RF signals and are used as a guideline in the design, prediction and evaluation of an advanced Dense Wavelength Division Multiplexing (DWDM) RoFSO system we are developing capable of transmitting multiple RF signals. An analytical modeling of the system is also conducted to identify key parameters in evaluating the performance of RF signal transmission using FSO links. The results confirm that the effect of scintillation on RF-FSO system performance can be estimated by using a simple estimation equation and satisfactory result are obtained from comparing the experimental and theoretical derived data under weak to strong turbulence condition.

The deterioration and deformation of a free-space optical beam wave-front as it propagates through the atmosphere can reduce the link availability and may introduce burst errors thus degrading the performance of the system. We investigate the suitability of utilizing soft-computing (SC) based tools for improving performance of free-space optical (FSO) communications systems. The SC based tools are used for the prediction of key parameters of a FSO communications system. Measured data collected from an experimental FSO communication system is used as training and testing data for a proposed multi-layer neural network predictor (MNNP) used to predict future parameter values. The predicted parameters are essential for reducing transmission errors by improving the antenna's accuracy of tracking data beams. This is particularly essential for periods considered to be of strong atmospheric turbulence. The parameter values predicted using the proposed tool show acceptable conformity with original measurements.