scholarly journals Novel Approaches for Estimating Female Sex Worker Population Size in Conflict-Affected South Sudan (Preprint)

2018 ◽  
Author(s):  
Alfred Geoffrey Okiria ◽  
Alex Bolo ◽  
Victoria Achut ◽  
Golda Ceasar Arkangelo ◽  
Acaga Taban Ismail Michael ◽  
...  
Keyword(s):  
Resource Allocation ◽  
Population Size ◽  
Lower Estimate ◽  
South Sudan ◽  
Multiplier Method ◽  
Female Population ◽  
Female Sex ◽  
Unique Object ◽  
Capture Recapture ◽  
Inform Resource Allocation

BACKGROUND Limited data exist describing the population size of female sex workers (FSW) in South Sudan. A population size estimation exercise among FSW was undertaken in Juba and Nimule during the Eagle Survey. OBJECTIVE The study aimed to estimate the number of FSW in Juba and Nimule to inform resource allocation and service provision for FSW. METHODS We utilized service and unique object multipliers, and 3-source capture-recapture methods in conjunction with a respondent-driven sampling (RDS) survey to estimate the number of FSW in Juba and Nimule. For service multiplier, the number of FSW testing for HIV in 2015 (Juba) and 2016 (Nimule) was obtained from the LINKAGES program targeting FSW. Survey participants were asked whether they had been tested for HIV by LINKAGES during the relevant period. A total of 2 separate unique object distributions were conducted in Juba and Nimule. In Nimule, these were combined to produce a 3-source capture-recapture estimate. The exercise involved distribution of key chains and bangles to FSW, documentation of the number of those who received unique objects, and questions during RDS survey to assess whether participants received unique objects. RESULTS In Juba, the service multiplier method yielded an estimate of 5800 (95% CI 4927-6673) FSW. The unique object estimate (key chain and RDS participation) yielded 5306 (95% CI 4673-5939). Another estimate using RDS participation and receipt of a bangle yielded a much lower estimate of 1863 (95% CI 1776-1951), as did a 2-source estimate of key chain and bangle (2120, 95% CI 2028-2211). A 3-source capture-recapture estimate could not be produced because aggregate rather than individual level data were collected during the third capture. The multiplier estimate using key chain and RDS participation was taken as the final population estimate for FSW in Juba, which constitutes more than 6% of the female population aged 15 to 64 years. In Nimule, the service multiplier method yielded an estimate of 9384 (95% CI 8511-10,257). The 2-source estimates for key chain and RDS yielded 6973 (95% CI 4759-9186); bangles and RDS yielded a higher estimate of 13,104 (95% CI 7101-19,106); key chains and bangles yielded a lower estimate of 1322 (95% CI 1223-1420). The 3-source capture-recapture method using Bayesian nonparametric latent-class model-based estimate yielded a population of 2694 (95% CI 1689-6945), and this was selected as the final estimate for Nimule, which constitutes nearly 40% of female population aged 15 to 64 years. CONCLUSIONS The service and unique object multiplier, and 3-source capture-recapture methods were successfully used to estimate the number of FSW in Nimule, whereas service and unique object multiplier methods were successfully used in Juba. These methods yielded higher than previously estimated FSW population sizes. These estimates will inform resource allocation and advocacy efforts to support services for FSW.

scholarly journals Population Size Estimation of Venue-Based Female Sex Workers in Ho Chi Minh City, Vietnam: Capture-Recapture Exercise (Preprint)

2018 ◽  
Author(s):  
Giang Le ◽  
Nghia Khuu ◽  
Van Thi Thu Tieu ◽  
Phuc Duy Nguyen ◽  
Hoa Thi Yen Luong ◽  
...  
Keyword(s):  
Population Size ◽  
Sex Workers ◽  
Female Sex Workers ◽  
Population Size Estimation ◽  
Ho Chi Minh City ◽  
Size Estimation ◽  
Female Sex ◽  
Unique Object ◽  
Capture Recapture ◽  
Selection Of

BACKGROUND There is limited population size estimation of female sex workers (FSWs) in Ho Chi Minh City (HCMC)—the largest city in Vietnam. Only 1 population size estimation among venue-based female sex workers (VFSWs) was conducted in 2012 in HCMC. Appropriate estimates of the sizes of key populations are critical for resource allocation to prevent HIV infection. OBJECTIVE The aim of this study was to estimate the population size of the VFSWs from December 2016 to January 2017 in HCMC, Vietnam. METHODS A multistage capture-recapture study was conducted in HCMC. The capture procedures included selection of districts using stratified probability proportion to size, mapping to identify venues, approaching all VFSWs to screen their eligibility, and then distribution of a unique object (a small pink makeup bag) to all eligible VFSWs in all identified venues. The recapture exercise included equal probability random selection of a sample of venues from the initial mapping and then approaching FSWs in those venues to determine the number and proportion of women who received the unique object. The proportion and associated confidence bounds, calculated using sampling weights and accounting for study design, were then divided by the number of objects distributed to calculate the number of VFSWs in the selected districts. This was then multiplied by the inverse of the proportion of districts selected to calculate the number of VFSWs in HCMC as a whole. RESULTS Out of 24 districts, 6 were selected for the study. Mapping identified 573 venues across which 2317 unique objects were distributed in the first capture. During the recapture round, 103 venues were selected and 645 VFSWs were approached and interviewed. Of those, 570 VFSWs reported receiving the unique object during the capture round. Total estimated VFSWs in the 6 selected districts were 2616 (95% CI 2445-3014), accounting for the fact that only 25% (6/24) of total districts were selected gives an overall estimate of 10,465 (95% CI 9782-12,055) VFSWs in HCMC. CONCLUSIONS The capture-recapture exercise provided an estimated number of VFSWs in HCMC. However, for planning HIV prevention and care service needs among all FSWs, studies are needed to assess the number of sex workers who are not venue-based, including those who use social media platforms to sell services.

scholarly journals Population Size Estimation of Venue-Based Female Sex Workers in Ho Chi Minh City, Vietnam: Capture-Recapture Exercise

10.2196/10906 ◽  
2019 ◽  
Vol 5 (1) ◽  
pp. e10906 ◽  
Author(s):  
Giang Le ◽  
Nghia Khuu ◽  
Van Thi Thu Tieu ◽  
Phuc Duy Nguyen ◽  
Hoa Thi Yen Luong ◽  
...  
Keyword(s):  
Population Size ◽  
Sex Workers ◽  
Female Sex Workers ◽  
Population Size Estimation ◽  
Ho Chi Minh City ◽  
Size Estimation ◽  
Female Sex ◽  
Capture Recapture

shinyrecap: A Shiny Application for Population Size Estimation from Capture-Recapture Data (Preprint)

2021 ◽  
Author(s):  
Anne F. McIntyre ◽  
Ian E. Fellows ◽  
Steve Gutreuter ◽  
Wolfgang Hladik
Keyword(s):  
Population Size ◽  
Sex Workers ◽  
Female Sex Workers ◽  
Population Size Estimation ◽  
Sub Saharan Africa ◽  
Size Estimation ◽  
Female Sex ◽  
Populations At Risk ◽  
Population Size Estimates ◽  
Capture Recapture

BACKGROUND Capture-recapture is often used to estimate the size of populations at risk for HIV, including female sex workers, men who have sex with men, and people who inject drugs. These population size estimates are critical in determining resource allocation for HIV services geared toward these communities. OBJECTIVE Compared to the commonly used two-source capture-recapture, capture-recapture relying on three (or more) samples can provide more robust PSE but involve far more complex statistical analysis. shinyrecap is designed to provide a user-friendly interface for the field epidemiologist. METHODS shinyrecap is built on the Shiny web application framework for R. This allows it to seamlessly integrate with the sophisticated CRC statistical packages. Additionally, the application may be accessed online or run locally on the user’s machine. RESULTS The application enables users to engage in sample size calculation based on a simulation framework. It assists in the proper formatting of collected data by providing a tool to convert commonly used formats to that used by analysis software. A wide variety of methodologies are supported by the analysis tool, including log-linear, Bayesian model averaging, and Bayesian latent class models. For each methodology, diagnostics and model checking interfaces are provided. CONCLUSIONS Through a use case, we demonstrate the broad utility of this powerful tool with three-source capture-recapture data to produce population size estimation for female sex workers in a subnational unit of a country in sub-Saharan Africa.

Estimating the Population Size of Female Sex Worker Population in Tehran, Iran: Application of Direct Capture–Recapture Method

2017 ◽  
Vol 21 (8) ◽  
pp. 2394-2400 ◽  
Author(s):  
Manoochehr Karami ◽  
Salman Khazaei ◽  
Jalal Poorolajal ◽  
Alireza Soltanian ◽  
Mansour Sajadipoor
Keyword(s):  
Population Size ◽  
Female Sex Worker ◽  
Direct Capture ◽  
Sex Worker ◽  
Female Sex ◽  
Capture Recapture

scholarly journals National and subnational size estimation of female sex workers in Ghana 2020: Comparing 3-source capture-recapture with other approaches

PLoS ONE ◽  
2021 ◽  
Vol 16 (9) ◽  
pp. e0256949
Author(s):  
Chris Guure ◽  
Samuel Dery ◽  
Seth Afagbedzi ◽  
Waimar Tun ◽  
Sharon Stucker Weir ◽  
...  
Keyword(s):  
Population Size ◽  
Sex Workers ◽  
Female Sex Workers ◽  
Total Population ◽  
Preventive Treatment ◽  
Size Estimation ◽  
Female Sex ◽  
Care Services ◽  
Population Size Estimate ◽  
Capture Recapture

Background Key Population size estimation (PSE) is instrumental for HIV/STI preventive, treatment and care services planning, implementation and delivery. The objective was to estimate the overall population of female sex workers (FSW) in all the 16 regions of Ghana using different PSE methods. Method Mapping of venues and complete enumeration of seaters was conducted at the formative stage prior to the bio-behavioral survey (BBS). Three PSE methods were used to derive the size estimates of FSW in the 16 regions. These include: Capture-recapture (CRC), service multiplier and three-source capture recapture (3SCRC) methods. The final choice of the estimation method used to estimate the roamer population was 3SCRC. This method was chosen because of its perfect record-linkage–hierarchic combination of three names that minimizes overmatching as well as the addition of an interaction term in the model which corrects for the dependencies in CRC. Results The total population size estimate of the female sex workers in the country obtained for roamers using capture re-capture was 41,746 (95% CI: 41,488–41,932). Using the service multiplier, the total population for both the roamers and seaters was 41,153 (95% CI: 37,242–45,984). The 3-source capture re-capture yielded 55,686 roamers FSW (95% CI: 47,686–63,686). The seater population was 4,363 FSW based on census/complete enumeration. The total population size estimate of FSW (seaters and roamers) in Ghana was 60,049 when 3SCRC and census were added. This represents about 0.76% of all estimated adult females aged 15-49yrs in Ghana. Conclusion We report population size estimates (PSE) for FSW in Ghana. These estimates are the results of 3SCRC. These findings provide a valid and reliable source of information that should be referenced by government officials and policymakers to plan, implement and provide HIV/STI preventive, treatment, and care services for FSW in Ghana.

scholarly journals Novel Approaches for Estimating Female Sex Worker Population Size in Conflict-Affected South Sudan

10.2196/11576 ◽  
2019 ◽  
Vol 5 (1) ◽  
pp. e11576 ◽  
Author(s):  
Alfred Geoffrey Okiria ◽  
Alex Bolo ◽  
Victoria Achut ◽  
Golda Ceasar Arkangelo ◽  
Acaga Taban Ismail Michael ◽  
...  
Keyword(s):  
Population Size ◽  
South Sudan ◽  
Female Sex Worker ◽  
Sex Worker ◽  
Female Sex ◽  
Novel Approaches

Estimating the population size of people who inject drugs in Ho Chi Minh City, Vietnam: A two-survey capture-recapture exercise (Preprint)

2019 ◽  
Author(s):  
Abu Abdul-Quader
Keyword(s):  
Population Size ◽  
Illicit Drugs ◽  
People Who Inject Drugs ◽  
Care Service ◽  
Ho Chi Minh City ◽  
Size Estimation ◽  
Population Size Estimates ◽  
Capture Recapture ◽  
The City ◽  
Size Estimates

BACKGROUND Population size estimation of people who inject drugs (PWID) in Ho Chi Minh City (HCMC), Vietnam relied on the UNAIDS Estimation and Projection Package and reports from the city police department. The two estimates vary widely. OBJECTIVE To estimate the population size of people who inject drugs in Ho Chi Minh City, Vietnam METHODS Using Respondent-driven sampling (RDS), we implemented two-source capture-recapture method to estimate the population size of PWID in HCMC in 2017 in 7 out of 24 districts. The study included men or women aged at least 18 years who reported injecting illicit drugs in the last 90 days and who had lived in the city the past six months. We calculated two sets of size estimates, the first assumed that all participants in each survey round resided in the district where the survey was conducted, the second, used the district of residence as reported by the participant. District estimates were summed to obtain an aggregate estimate for the seven districts. To calculate the city total, we weighted the population size estimates for each district by the inverse of the stratum specific sampling probabilities. RESULTS The first estimate resulted in a population size of 19,155 (95% CI: 17,006–25,039). The second one generated a smaller population size estimate of 12,867 (95% CI: 11,312–17,393). CONCLUSIONS The two-survey capture-recapture exercise provided two disparate estimates of PWID in HCMC. For planning HIV prevention and care service needs among PWID in HCMC, both estimates may need to be taken into consideration together with size estimates from other sources.

scholarly journals The wildcat Felis silvestris in northern Turkey: assessment of status using camera trapping

Oryx ◽  
2011 ◽  
Vol 45 (1) ◽  
pp. 112-118 ◽  
Author(s):  
Özgün Emre Can ◽  
İrfan Kandemi̇r ◽  
İnci̇ Togan
Keyword(s):  
Population Size ◽  
Camera Traps ◽  
Sampling Effort ◽  
Felis Silvestris ◽  
Forest Patch ◽  
Western Turkey ◽  
Lack Of Information ◽  
The Status ◽  
Capture Recapture ◽  
Estimate Population Size

AbstractThe wildcat Felis silvestris is a protected species in Turkey but the lack of information on its status is an obstacle to conservation initiatives. To assess the status of the species we interviewed local forestry and wildlife personnel and conducted field surveys in selected sites in northern, eastern and western Turkey during 2000–2007. In January–May 2006 we surveyed for the wildcat using 16 passive infrared-trigged camera traps in Yaylacı k Research Forest, a 50-km2 forest patch in Yenice Forest in northern Turkey. A total sampling effort of 1,200 camera trap days over 40 km2 yielded photo-captures of eight individual wildcats over five sampling occasions. Using the software MARK to estimate population size the closed capture–recapture model M0, which assumes a constant capture probability among all occasions and individuals, best fitted the capture history data. The wildcat population size in Yaylacı k Research Forest was estimated to be 11 (confidence interval 9–23). Yenice Forest is probably one of the most important areas for the long-term conservation of the wildcat as it is the largest intact forest habitat in Turkey with little human presence, and without human settlements, and with a high diversity of prey species. However, it has been a major logging area and is not protected. The future of Yenice Forest and its wildcat population could be secured by granting this region a protection status and enforcing environmental legislation.

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