Ecology of phlebotomine sand flies in the rural community of Mont Rolland (Thiès region, Senegal): area of transmission of canine leishmaniasis

Background

Different epidemiological studies previously indicated that canine leishmaniasis is present in the region of Thiès (Senegal). However, the risks to human health, the transmission cycle and particularly the implicated vectors are unknown.

Methodology/Principal Findings

To improve our knowledge on the population of phlebotomine sand flies and the potential vectors of canine leishmaniasis, sand flies were collected using sticky traps, light traps and indoor spraying method using pyrethroid insecticides in 16 villages of the rural community of Mont Rolland (Thiès region) between March and July 2005. The 3788 phlebotomine sand flies we collected (2044 males, 1744 females) were distributed among 9 species of which 2 belonged to the genus Phlebotomus: P. duboscqi (vector of cutaneous leishmaniasis in Senegal) and P. rodhaini. The other species belonged to the genus Sergentomyia: S. adleri, S. clydei, S. antennata, S. buxtoni, S. dubia, S. schwetzi and S. magna. The number of individuals and the species composition differed according to the type of trap, suggesting variable, species-related degrees of endophily or exophily. The two species of the genus Phlebotomus were markedly under-represented in comparison to the species of the genus Sergentomyia. This study also shows a heterogeneous spatial distribution within the rural community that could be explained by the different ecosystems and particularly the soil characteristics of this community. Finally, the presence of the S. dubia species appeared to be significantly associated with canine leishmaniasis seroprevalence in dogs.

Conclusions/Significance

Our data allow us to hypothesize that the species of the genus Sergentomyia and particularly the species S. dubia and S. schwetzi might be capable of transmitting canine leishmaniasis. These results challenge the dogma that leishmaniasis is exclusively transmitted by species of the genus Phlebotomus in the Old World. This hypothesis should be more thoroughly evaluated.     

Estimating herbaceous aboveground biomass in Sahelian rangelands using Structure from Motion data collected on the ground and by UAV

Herbaceous aboveground biomass (HAB) is a key indicator of grassland vegetation and indirect estimation tools, such as remote sensing imagery, increase the potential for covering larger areas in a timely and cost‐efficient way. Structure from Motion (SfM) is an image analysis process that can create a variety of 3D spatial models as well as 2D orthomosaics from a set of images. Computed from Unmanned Aerial Vehicle (UAV) and ground camera measurements, the SfM potential to estimate the herbaceous aboveground biomass in Sahelian rangelands was tested in this study. Both UAV and ground camera recordings were used at three different scales: temporal, landscape, and national (across Senegal). All images were processed using PIX4D software (photogrammetry software) and were used to extract vegetation indices and heights. A random forest algorithm was used to estimate the HAB and the average estimation errors were around 150 g m⁻² for fresh mass (20% relative error) and 60 g m⁻² for dry mass (around 25% error). A comparison between different datasets revealed that the estimates based on camera data were slightly more accurate than those from UAV data. It was also found that combining datasets across scales for the same type of tool (UAV or camera) could be a useful option for monitoring HAB in Sahelian rangelands or in other grassy ecosystems.     

Low infectivity of Plasmodium falciparum gametocytes to Anopheles gambiae following treatment with sulfadoxine-pyrimethamine in Mali

Sulfadoxine-pyrimethamine (SP) treatment increases the rate of gametocyte carriage and selects SP resistance-conferring mutations in Plasmodium falciparum dihydrofolate reductase (DHFR) and dihydropteroate synthase (DHPS), raising concerns of increased malaria transmission and spread of drug resistance. In a setting in Mali where SP was highly efficacious, we measured the prevalence of DHFR and DHPS mutations in P. falciparum infections with microscopy-detected gametocytes following SP treatment, and used direct feeding to assess infectivity to Anopheles gambiae sensu lato. Children and young adults presenting with uncomplicated malaria were treated with SP or chloroquine and followed for 28 days. Gametocyte carriage peaked at 67% 1 week after treatment with a single dose of SP. Those post-SP gametocytes carried significantly more DHFR and DHPS mutations than pre-treatment asexual parasites from the same population. Only 0.5% of 1728 mosquitoes fed on SP-treated gametocyte carriers developed oocysts, while 11% of 198 mosquitoes fed on chloroquine-treated gametocyte carriers were positive for oocysts. This study shows that in an area of high SP efficacy, although SP treatment sharply increased gametocyte carriage, the infectiousness of these gametocytes to the vector may be very low. Accurate and robust methods for measuring infectivity are needed to guide malaria control interventions that affect transmission.     

Ethnicity Is an Independent Determinant of Age-Specific PSA Level: Findings from a Multiethnic Asian Setting

Objectives

To study the baseline PSA profile and determine the factors influencing the PSA levels within a multiethnic Asian setting.

Materials and Methods

We conducted a cross-sectional study of 1054 men with no clinical evidence of prostate cancer, prostate surgery or 5α-reductase inhibitor treatment of known prostate conditions. The serum PSA concentration of each subject was assayed. Potential factors associated with PSA level including age, ethnicity, height, weight, family history of prostate cancer, lower urinary tract voiding symptoms (LUTS), prostate volume and digital rectal examination (DRE) were evaluated using univariable and multivariable analysis.

Results

There were 38 men (3.6%) found to have a PSA level above 4 ng/ml and 1016 (96.4%) with a healthy PSA (≤4 ng/ml). The median PSA level of Malay, Chinese and Indian men was 1.00 ng/ml, 1.16 ng/ml and 0.83 ng/ml, respectively. Indians had a relatively lower median PSA level and prostate volume than Malays and Chinese, who shared a comparable median PSA value across all 10-years age groups. The PSA density was fairly similar amongst all ethnicities. Further analysis showed that ethnicity, weight and prostate volume were independent factors associated with age specific PSA level in the multivariable analysis (p<0.05).

Conclusion

These findings support the concept that the baseline PSA level varies between different ethnicities across all age groups. In addition to age and prostate volume, ethnicity may also need to be taken into account when investigating serum PSA concentrations in the multiethnic Asian population.     

Cardiovascular Risk Factors and Ethnicity Are Independent Factors Associated with Lower Urinary Tract Symptoms

Objectives

To determine the lower urinary tract symptoms (LUTS) profile and factors affecting its degree of severity including cardiovascular risk profile, age, ethnicity, education level and prostate volume in a multiethnic Asian setting.

Materials and Methods

We conducted a cross-sectional study of 1021 men aged 40–79 years with no clinical evidence of prostate cancer, prostate surgery or 5α-reductase inhibitor treatment of known prostate conditions. The severity of LUTS was assessed using the International Prostate Symptom Score (IPSS). Potential factors associated with LUTS including age, ethnicity, education, history of hypertension, diabetes and hypercholesterolemia, height, weight, and prostate volume were evaluated using univariable and multivariable analyses.

Results

There were 506 (50%) men found to have moderate-to-severe LUTS attaining an IPSS above 7. Overall, nocturia (45.5%) was the most frequently reported symptom. Multivariable analysis showed that age, ethnicity, prostate volume and history of hypertension and hypercholesterolemia were independent factors associated with severity of LUTS (p < 0.05). Considering individual lower urinary tract symptoms, we found a strong association of storage symptom with history of hypertension and hypercholesterolemia. Malay men were significantly bothered by post micturition symptom compared to their Chinese and Indian counterparts. Stratified analyses of LUTS demonstrated a mutually exclusive cardiovascular risk factors profile defined by ethnicity.

Conclusion

Severity of LUTS varies between different ethnicities across all age groups. In addition to age and prostate volume, ethnicity and cardiovascular risk factors including hypertension and hypercholesterolemia may also need to be taken into account in managing men with LUTS.     

To Share or Not to Share: Malaysian Healthcare Professionals' Views on Localized Prostate Cancer Treatment Decision Making Roles

Aim

To explore the views of Malaysian healthcare professionals (HCPs) on stakeholders’ decision making roles in localized prostate cancer (PCa) treatment.

Methods

Qualitative interviews and focus groups were conducted with HCPs treating PCa. Data was analysed using a thematic approach. Four in-depth interviews and three focus group discussions were conducted between December 2012 and March 2013 using a topic guide. Interviews were audio-recorded, transcribed verbatim, and analysed thematically.

Findings

The participants comprised private urologists (n = 4), government urologists (n = 6), urology trainees (n = 6), government policy maker (n = 1) and oncologists (n = 3). HCP perceptions of the roles of the three parties involved (HCPs, patients, family) included: HCP as the main decision maker, HCP as a guide to patients’ decision making, HCP as a facilitator to family involvement, patients as main decision maker and patient prefers HCP to decide. HCPs preferred to share the decision with patients due to equipoise between prostate treatment options. Family culture was important as family members often decided on the patient’s treatment due to Malaysia’s close-knit family culture.

Conclusions

A range of decision making roles were reported by HCPs. It is thus important that stakeholder roles are clarified during PCa treatment decisions. HCPs need to cultivate an awareness of sociocultural norms and family dynamics when supporting non-Western patients in making decisions about PCa.     

Laboratory and Field Evaluation of the Partec CyFlow MiniPOC for Absolute and Relative CD4 T-Cell Enumeration

BackgroundA new CD4 point-of-care instrument, the CyFlow miniPOC, which provides absolute and percentage CD4 T-cells, used for screening and monitoring of HIV-infected patients in resource-limited settings, was introduced recently. We assessed the performance of this novel instrument in a reference laboratory and in a field setting in Senegal.MethodologyA total of 321 blood samples were obtained from 297 adults and 24 children, all HIV-patients attending university hospitals in Dakar, or health centers in Ziguinchor. Samples were analyzed in parallel on CyFlow miniPOC, FACSCount CD4 and FACSCalibur to assess CyFlow miniPOC precision and accuracy.ResultsAt the reference lab, CyFlow miniPOC, compared to FACSCalibur, showed an absolute mean bias of -12.6 cells/mm³ and a corresponding relative mean bias of -2.3% for absolute CD4 counts. For CD4 percentages, the absolute mean bias was -0.1%. Compared to FACSCount CD4, the absolute and relative mean biases were -31.2 cells/mm³ and -4.7%, respectively, for CD4 counts, whereas the absolute mean bias for CD4 percentages was 1.3%. The CyFlow miniPOC was able to classify HIV-patients eligible for ART with a sensitivity of ≥ 95% at the different ART-initiation thresholds (200, 350 and 500 CD4 cells/mm3). In the field lab, the room temperature ranged from 30 to 35°C during the working hours. At those temperatures, the CyFlow miniPOC, compared to FACSCount CD4, had an absolute and relative mean bias of 7.6 cells/mm³ and 2.8%, respectively, for absolute CD4 counts, and an absolute mean bias of 0.4% for CD4 percentages. The CyFlow miniPOC showed sensitivity equal or greater than 94%.ConclusionThe CyFlow miniPOC showed high agreement with FACSCalibur and FACSCount CD4. The CyFlow miniPOC provides both reliable absolute CD4 counts and CD4 percentages even under the field conditions, and is suitable for monitoring HIV-infected patients in resource-limited settings.     

Serum alpha-fetoprotein predicts treatment outcome in chronic hepatitis C patients regardless of HCV genotype

We examined the association between serum alpha-fetoprotein (AFP) level and sustained virological response (SVR) in 93 chronic hepatitis C patients. The SVR rate was much higher among patients with serum AFP levels below rather than above the median value (5.7 ng/ml) (58.7% and 19.2%, respectively; P<0.0001). Serum AFP should be added to the list of factors predictive of treatment response in chronic hepatitis C.