scholarly journals Prevalence of asymptomatic P. falciparum gametocyte carriage among school children in Mbita, Western Kenya and assessment of the association between gametocyte density, multiplicity of infection and mosquito infection prevalence.

2021 ◽  
Vol 5 ◽  
pp. 259
Author(s):  
Abdoulie O. Touray ◽  
Victor A. Mobegi ◽  
Fred Wamunyokoli ◽  
Hellen Butungi ◽  
Jeremy K. Herren
Keyword(s):  
Infection Prevalence ◽  
Multiplicity Of Infection ◽  
Gametocyte Density ◽  
Western Kenya ◽  
Gametocyte Carriage ◽  
Membrane Feeding ◽  
Parasite Infections ◽  
Study Population ◽  
Associated Risk Factors ◽  
Mosquito Infection

Background: Asymptomatic Plasmodium falciparum gametocyte carriers are reservoirs for sustaining transmission in malaria endemic regions. Gametocyte presence in the host peripheral blood is a predictor of capacity to transmit malaria. However, it does not always directly translate to mosquito infectivity. Factors that affect mosquito infectivity include, gametocyte sex-ratio and density, multiplicity of infection (MOI), and host and vector anti-parasite immunity. We assess the prevalence of gametocyte carriage and some of its associated risk factors among asymptomatic schoolchildren in Western Kenya and to further analyse the association between gametocyte density, multiplicity of infection (MOI) and mosquito infection prevalence. Methods: P. falciparum parasite infections were detected by RDT (Rapid Diagnostic Test) and microscopy among schoolchildren (5-15 years old). Blood from 37 microscopy positive gametocyte carriers offered to laboratory reared An. gambiae s.l. mosquitoes. A total of 3395 fully fed mosquitoes were screened for Plasmodium sporozoites by ELISA. P. falciparum was genotyped using 10 polymorphic microsatellite markers. The association between MOI and gametocyte density and mosquito infection prevalence was investigated. Results: A significantly higher prevalence of P. falciparum infection was found in males 31.54% (764/2422) (p-value < 0.001) compared to females 26.72% (657/2459). The microscopic gametocyte prevalence among the study population was 2% (84/4881). Children aged 5-9 years have a higher prevalence of gametocyte carriage (odds ratios = 2.1 [95% CI = 1.3–3.4], P = 0.002) as compared to children aged 10-15 years. After offering gametocyte positive blood to An. gambiae s.l. by membrane feeding assay, our results indicated that 68.1% of the variation in mosquito infection prevalence was accounted for by gametocyte density and MOI (R-SQR. = 0.681, p < 0.001). Conclusions: We observed a higher risk of gametocyte carriage among the younger children (5-9 years). Gametocyte density and MOI significantly predicted mosquito infection prevalence.

scholarly journals Assessment of the Relationship Between Gametocyte Density, Multiplicity of Infection and Mosquito Infectivity in Plasmodium Falciparum Infections

2020 ◽  
Author(s):  
Abdoulie O. Touray ◽  
Victor Atunga Mobegi ◽  
Fred Wamunyokoli ◽  
Hellen Butungi ◽  
Jeremy K. Herren
Keyword(s):  
Plasmodium Falciparum ◽  
Significant Risk ◽  
Sub Saharan Africa ◽  
Infection Prevalence ◽  
Multiplicity Of Infection ◽  
Gametocyte Density ◽  
Western Kenya ◽  
Gametocyte Carriage ◽  
Study Population ◽  
Mosquito Infection

Abstract Background: Malaria is a major public health threat in sub-Saharan Africa. Asymptomatic P. falciparum gametocyte carriers are potential infectious reservoirs for sustaining transmission in many malaria endemic regions. The aim of the study was to assess the prevalence of gametocyte carriage and some of its associated risk factors among asymptomatic schoolchildren (age 5-15 years) in Mbita, western Kenya and further analyse the association between gametocyte density, multiplicity of infection (MOI) and mosquito infection prevalence.Methods: Rapid diagnostic test (RDT) was used to screen for P. falciparum parasite infection among asymptomatic schoolchildren (5-15 years old) residing in Mbita, Western Kenya and the results were further verified using microscopy. Microscopy positive gametocyte carriers were selected to feed laboratory reared An. gambiae s.s. mosquitoes using membrane feeding method. Genomic DNA was extracted from dry blood spots (DBS) samples and P. falciparum populations were genotyped using 10 polymorphic microsatellite markers. Assessment of the association between MOI and gametocyte density and mosquito infection rates was conducted. Results: The prevalence of Plasmodium falciparum infection among the study population was 29.11% (1421/4881). A significantly higher prevalence of P. falciparum infection was found among the male gender 31.54% (764/2422) (p-value < 0.001) compared to the females 26.72% (657/2459). The microscopy gametocyte prevalence among the study population was 2% (84/4881). Children (5-9 years) have a higher risk of gametocyte carriage (Odd Ratios = 2.1 [95% CI = 1.3–3.4], P = 0.002) as compared to those between the ages of 10-15 years. Our results indicate that, about 68.1% of the variation in mosquito infection prevalence is accounted for by the gametocytes density and MOI (R-SQR. = 0.681, p < 0.001).Conclusion: The study reports a P. falciparum infection prevalence of 29.11% with a gametocyte prevalence of 2% among the study population as determined by microscopy. Age was a significant risk factor for gametocyte carriage as indicated by the higher risk of gametocyte carriage among the younger children (5-9 years). The gametocyte density and multiplicity of infection statistically significantly predicted mosquito infection prevalence. Both of the variables added significantly to the prediction, (p < 0.05).

scholarly journals Prevalence of asymptomatic P. falciparum gametocyte carriage in schoolchildren and assessment of the association between gametocyte density, multiplicity of infection and mosquito infection prevalence

2020 ◽  
Vol 5 ◽  
pp. 259
Author(s):  
Abdoulie O. Touray ◽  
Victor A. Mobegi ◽  
Fred Wamunyokoli ◽  
Hellen Butungi ◽  
Jeremy K. Herren
Keyword(s):  
Significant Risk ◽  
Significant Risk Factor ◽  
Sub Saharan Africa ◽  
Infection Prevalence ◽  
Multiplicity Of Infection ◽  
Gametocyte Density ◽  
Feeding Method ◽  
Gametocyte Carriage ◽  
Membrane Feeding ◽  
Mosquito Infection

Background: Malaria is a major public health threat in sub-Saharan Africa. Asymptomatic Plasmodium falciparum gametocyte carriers are potential infectious reservoirs for sustaining transmission in many malaria endemic regions. The aim of the study was to assess the prevalence of gametocyte carriage and some of its associated risk factors among asymptomatic schoolchildren in Western Kenya and further analyse the association between gametocyte density, multiplicity of infection (MOI) and mosquito infection prevalence. Methods: Rapid diagnostic tests were used to screen for P. falciparum parasite infection among schoolchildren (5-15 years old) and the results were verified using microscopy. Microscopy positive gametocyte carriers were selected to feed laboratory reared An. gambiae s.l. mosquitoes using membrane feeding method. Genomic DNA was extracted from dry blood spot samples and P. falciparum populations were genotyped using 10 polymorphic microsatellite markers. Assessment of the association between MOI and gametocyte density and mosquito infection prevalence was conducted. Results: A significantly higher prevalence of P. falciparum infection was found in males 31.54% (764/2422) (p-value < 0.001) compared to females 26.72% (657/2459). The microscopy gametocyte prevalence among the study population was 2% (84/4881). Children aged 5-9 years have a higher prevalence of gametocyte carriage (odds ratios = 2.1 [95% CI = 1.3–3.4], P = 0.002) as compared to children aged 10-15 years. After challenging An. gambiae s.l. by membrane feeding assay on gametocyte positive patient blood, our results indicate that 68.1% of the variation in mosquito infection prevalence is accounted for by gametocyte density and MOI (R-SQR. = 0.681, p < 0.001). Conclusions: Age was a significant risk factor for gametocyte carriage, as indicated by the higher risk of gametocyte carriage among the younger children (5-9 years). Gametocyte density and MOI statistically significantly predicted mosquito infection prevalence. Both of the variables added significantly to the prediction (p < 0.05).

scholarly journals Assessment of the relationship between gametocyte density, multiplicity of infection and mosquito infectivity in Plasmodium falciparum infections

2020 ◽  
Author(s):  
Abdoulie Touray ◽  
Victor Atunga Mobegi ◽  
Fred Wamunyokoli ◽  
Hellen Butungi ◽  
Jeremy K. Herren
Keyword(s):  
Plasmodium Falciparum ◽  
Falciparum Infection ◽  
Sub Saharan Africa ◽  
Multiplicity Of Infection ◽  
Strong Positive Correlation ◽  
Gametocyte Density ◽  
Western Kenya ◽  
Gametocyte Carriage ◽  
Study Population ◽  
Mosquito Infection

Abstract Background: Malaria is a major public health threat in sub-Saharan Africa. Asymptomatic P. falciparum gametocyte carriers are potential infectious reservoirs for sustaining transmission in many malaria endemic regions. The aim of the study was to assess the prevalence of gametocyte carriage and some of its associated risk factors among asymptomatic schoolchildren (age 5-15 years) in Mbita, western Kenya and further analyse the association between gametocyte density, multiplicity of infection (MOI) and mosquito infectivity. Methods: Rapid diagnostic test (RDT) was used to screen for P. falciparum parasite infection among asymptomatic schoolchildren (5-15 years old) residing in Mbita, Western Kenya and the results were further verified using microscopy. Participants positive for P. falciparum infection were further screened for gametocyte carriage and those positive were used to feed laboratory reared An. gambiae s.s. mosquitoes using membrane feeding method. Genomic DNA was extracted from dry blood spots (DBS) samples and P. falciparum populations were genotyped using 10 polymorphic microsatellite markers. Assessment of the association between MOI and gametocyte density and mosquito infection rates was conducted. Results: The prevalence of Plasmodium falciparum infection among the study population was 29.1%. A significantly higher P. falciparum infection was found among the male gender (n=764, p -value < 0.05) compared to the females (n=657). Gametocyte prevalence among the study population was 2%. Children (5-9 years) have a higher risk of gametocyte carriage (Odd Ratios = 2.1 [95% CI = 1.3–3.4], P = 0.002). Our results indicate a significant and positive combined effect of gametocyte density and MOI on mosquito infection rate (R = 0.825, p < 0.0001). Conclusion: The study reports a relatively stable year-round gametocyte carriage among the study population. This pattern of gametocyte carriage signals the role of schoolchildren in maintaining malaria transmission in the study area. A strong positive correlation was found between gametocyte density, multiplicity of infection and mosquito infectivity.

scholarly journals Optimization of Plasmodium vivax sporozoite production from Anopheles stephensi in South West India

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Ajeet Kumar Mohanty ◽  
Charles de Souza ◽  
Deepika Harjai ◽  
Prathamesh Ghavanalkar ◽  
Mezia Fernandes ◽  
...  
Keyword(s):  
South Asia ◽  
Plasmodium Vivax ◽  
Anopheles Stephensi ◽  
Parasite Development ◽  
Future Research ◽  
High Quality ◽  
Gametocyte Density ◽  
Feeding Experiments ◽  
South West ◽  
Membrane Feeding

Abstract Background Efforts to study the biology of Plasmodium vivax liver stages, particularly the latent hypnozoites, have been hampered by the limited availability of P. vivax sporozoites. Anopheles stephensi is a major urban malaria vector in Goa and elsewhere in South Asia. Using P. vivax patient blood samples, a series of standard membrane-feeding experiments were performed with An. stephensi under the US NIH International Center of Excellence for Malaria Research (ICEMR) for Malaria Evolution in South Asia (MESA). The goal was to understand the dynamics of parasite development in mosquitoes as well as the production of P. vivax sporozoites. To obtain a robust supply of P. vivax sporozoites, mosquito-rearing and mosquito membrane-feeding techniques were optimized, which are described here. Methods Membrane-feeding experiments were conducted using both wild and laboratory-colonized An. stephensi mosquitoes and patient-derived P. vivax collected at the Goa Medical College and Hospital. Parasite development to midgut oocysts and salivary gland sporozoites was assessed on days 7 and 14 post-feeding, respectively. The optimal conditions for mosquito rearing and feeding were evaluated to produce high-quality mosquitoes and to yield a high sporozoite rate, respectively. Results Laboratory-colonized mosquitoes could be starved for a shorter time before successful blood feeding compared with wild-caught mosquitoes. Optimizing the mosquito-rearing methods significantly increased mosquito survival. For mosquito feeding, replacing patient plasma with naïve serum increased sporozoite production > two-fold. With these changes, the sporozoite infection rate was high (> 85%) and resulted in an average of ~ 22,000 sporozoites per mosquito. Some mosquitoes reached up to 73,000 sporozoites. Sporozoite production could not be predicted from gametocyte density but could be predicted by measuring oocyst infection and oocyst load. Conclusions Optimized conditions for the production of high-quality P. vivax sporozoite-infected An. stephensi were established at a field site in South West India. This report describes techniques for producing a ready resource of P. vivax sporozoites. The improved protocols can help in future research on the biology of P. vivax liver stages, including hypnozoites, in India, as well as the development of anti-relapse interventions for vivax malaria.

Adverse effects and duration of treatment of TB in Canterbury, New Zealand

2021 ◽  
Vol 25 (12) ◽  
pp. 990-994
Author(s):  
J. Phillipson ◽  
N. Kuruppu ◽  
T. Chikura ◽  
C. McLachlan ◽  
L. McNeill ◽  
...  
Keyword(s):  
New Zealand ◽  
Response To Treatment ◽  
Therapeutic Drug ◽  
Duration Of Treatment ◽  
Extended Treatment ◽  
Patient Demographics ◽  
Disease Characteristics ◽  
Actual Duration ◽  
Study Population ◽  
Associated Risk Factors

BACKGROUND Treatment of TB is often extended beyond the recommended duration. The aim of this study was to assess prevalence of extended treatment and to identify associated risk factors. We also aimed to determine the frequency and type of adverse drug reactions (ADR) experienced by this study population.METHODS We performed a retrospective cohort study of all patients treated for active TB at Christchurch Hospital, Christchurch, New Zealand, between 1 March 2012 and 31 December 2018. Data for 192 patients were collected on patient demographics, disease characteristics and treatment characteristics, including planned and actual duration of treatment and ADRs.RESULTS Of 192 patients, 35 (18.2%) had treatment extended, and 85 (46.5%) of 183 with fully drug-susceptible TB received ≥9 months treatment. The most common reasons for extension were persistent or extensive disease and ADR. Extended treatment duration was not associated with any patient or disease characteristics. We found 35 (18.2%) patients experienced at least one ADR. The most common ADRs were hepatitis, rash and peripheral neuropathy.CONCLUSION TB treatment extension beyond WHO guidelines is common. Further research is needed to guide management of those with slow response to treatment. Methods for early detection of ADR, systems to improve adherence and therapeutic drug monitoring are potentially useful strategies.

scholarly journals Evaluation of Metabolic Syndrome and Its Associated Risk Factors in Type 2 Diabetes: A Descriptive Cross-Sectional Study at the Komfo Anokye Teaching Hospital, Kumasi, Ghana

2019 ◽  
Vol 2019 ◽  
pp. 1-8 ◽  
Author(s):  
Francis Agyemang-Yeboah ◽  
Benjamin Ackon Jnr. Eghan ◽  
Max Efui Annani-Akollor ◽  
Eliezer Togbe ◽  
Sampson Donkor ◽  
...  
Keyword(s):  
Risk Factors ◽  
Type 2 Diabetes ◽  
Metabolic Syndrome ◽  
Waist Circumference ◽  
Teaching Hospital ◽  
The Body ◽  
Diabetic Patients ◽  
Study Population ◽  
Associated Risk Factors

Background. Metabolic syndrome (MS) is a collection of cardiovascular risk factors comprising insulin resistance, dyslipidemia, obesity, and hypertension, which may cause further complications in diabetes. Although metabolic syndrome (MS) is increasing in incidence in diabetics and leading to significant cardiovascular diseases and mortality, there is dearth of data in Ghana. This study investigated metabolic syndrome, its prevalence, and its associated risk factors in type 2 diabetes at the Komfo Anokye Teaching Hospital, Kumasi, Ghana. Methods. The study involved 405 diabetic patients attending the Diabetic Clinic of the Komfo Anokye Teaching Hospital (KATH) Kumasi, in the Ashanti Region of Ghana. A well-structured questionnaire was used to obtain demographic background such as their age and gender. Anthropometric measurements were obtained using the Body Composition Monitor (Omron ® 500, Germany) which generated digital results on a screen and also by manual methods. Fasting venous blood was collected for the measurement of biochemical parameters comprising fasting plasma glucose (FPG), glycated haemoglobin (HbA1c), high density lipoprotein cholesterol (HDL-c), and triglyceride (TG). Metabolic syndrome was defined according to the National Cholesterol Education Program Adult Treatment Panel III (NCEP ATP III). Results. Out of the total of 405 participants, 81 were males and 324 were females, and the estimated mean age was 58.5 ± 9.9 years. The female patients exhibited higher mean waist circumference (WC) and mean hip circumference (HC) as well as an approximately higher body mass index than males (28.3 ± 5.1, 26.5 ± 4.2 for the female and male respectively). Overall, the prevalence of metabolic syndrome observed among the study population was 90.6%. Conclusions. The prevalence of metabolic syndrome observed among the study population was 90.6%, with a higher percentage in females than males. High triglyceride levels and high waist circumference were the main risk factors for MS in the diabetic population.

The Prevalence and Relationship between Periodontal Disease and Pre-term Low Birth Weight Infants at King Khalid University Hospital in Riyadh, Saudi Arabia

2004 ◽  
Vol 5 (2) ◽  
pp. 40-56 ◽  
Author(s):  
Sameer Abdullah Mokeem ◽  
Ghadeer Nabeel Molla ◽  
Thikriat Saleh Al-Jewair
Keyword(s):  
Risk Factors ◽  
Saudi Arabia ◽  
Birth Weight ◽  
Low Birth Weight ◽  
Periodontal Disease ◽  
University Hospital ◽  
Low Birth Weight Infants ◽  
Study Population ◽  
Associated Risk Factors ◽  
Periodontal Indices

Abstract The aim of this study was to examine the prevalence and relationship between periodontal disease and preterm low birth weight (PLBW) among Saudi mothers at King Khalid University Hospital (KKUH) in Riyadh, Saudi Arabia. The periodontal status and the relative risk were also analyzed. The study consisted of 30 cases [infants <37 weeks and/or weighing ≥2.500 kilograms (kg)] and a daily random sample of 60 controls [≥37 weeks and/or weighing >2.500 kg]. Clinical periodontal indices were measured on the labor wards. Associated risk factors for periodontal disease and PLBW were ascertained by means of a structured questionnaire and maternal notes. The prevalence of the PLBW was found to be 11.3%, and the prevalence of periodontal disease was high among the study population. The risk of PLBW remained high with increasing periodontal disease (odds ratio [OR] 4.21, 95% confident interval [CI] 1.99-8.93) despite controlling the other risk factors such as age, smoking, and social class. In conclusion, there is a correlation between periodontal disease and PLBW in KKUH. Citation Mokeem SA, Molla GN, Al-Jewair TS. The Prevalence and Relationship between Periodontal Disease and Pre-term Low Birth Weight Infants at King Khalid University Hospital in Riyadh, Saudi Arabia. J Contemp Dent Pract 2004 May;(5)2:040-056.

scholarly journals Vitamin D Status and Its Associated Risk Factors among Adults in the Southwest Region of Cameroon

2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Delphine A. Tangoh ◽  
Tobias O. Apinjoh ◽  
Yasir Mahmood ◽  
Robert V. Nyingchu ◽  
Beatrice A. Tangunyi ◽  
...  
Keyword(s):  
Risk Factors ◽  
Vitamin D ◽  
Vitamin D Deficiency ◽  
Hypovitaminosis D ◽  
Vitamin D Status ◽  
West Region ◽  
South West ◽  
Study Population ◽  
Associated Risk Factors ◽  
South West Region

Background. Vitamin D has been shown to exert its actions on the musculoskeletal, gastrointestinal, prostate, renal, endocrine, immune, and cardiovascular systems. Current reported data of hypovitaminosis D reveals a global pandemic, with an estimated one billion people worldwide presenting with hypovitaminosis D. Objective. This study aimed at investigating the vitamin D status and its associated risk factors in Cameroonians from the South West Region. Method. The study was a community- and hospital-based prospective longitudinal study. It was carried out during the dry and rainy seasons between the months of July and December 2015 in the South West Region of Cameroon involving 372 participants aged 35 years and above. After obtaining informed consent, a structured questionnaire was used to capture demographic data and risk factors of vitamin D deficiency. Blood samples were collected from the volunteer participants in the peak months of the rainy season and dry season, and the serum used to analyse for vitamin D by ELISA and calcium by spectrophotometry. 25(OH)D levels ≥75 nmol/L (≥30 ng/mL) were considered sufficient while levels <75 nmol/L were considered as hypovitaminosis D (insufficiency/deficiency). Results. Hypovitaminosis D (deficiency/insufficiency) was prevalent in 25.8% (96) of the study population, with only 3.2% (12) deficiency and 22.6% (84) insufficiency. There was a significant inverse relationship r=−0.119,p=0.02 between age and 25(OH)D levels; however, this relationship was not significant when controlled for gender, number of hours spent outdoors, and percentage of body covered. Gender, ethnic origin, percentage of body covered, time spent outdoors, and season did not influence serum vitamin D levels. Conclusion. Results of this study suggest that the prevalence of hypovitaminosis D is relatively low in this study population and only age is a risk factor of vitamin D deficiency.

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