Identification and characterization of immature Anopheles and culicines (Diptera: Culicidae) at three sites of varying malaria transmission intensities in Uganda.

Abstract Background: Over the last two decades, there has been remarkable progress in malaria control in sub-Saharan Africa, due mainly to the massive deployment of long-lasting insecticidal nets and indoor residual spraying. Despite these gains, it is clear that in many situations, additional interventions are needed to further reduce malaria transmission. Larval source management (LSM) is a potential supplementary measure that could be used to control malaria. However, prior to its roll-out, knowledge on ecology of larval aquatic habitats is required. Methods: Aquatic habitats colonized by Anopheles vectors were characterised at three sites of low, medium and high malaria transmission in Uganda from October 2011 to June 2016. Larval surveys were conducted along transects in each site and aquatic habitats described according to type and size. Anopheles mosquito larvae and pupae from the described habitats were sampled using standard dipping methods to determine larval densities. Larvae were identified as anopheline or culicine and counted. Pupae were not identified further. Binary logistic regression analysis was used to identify factors associated with the presence of Anopheles larvae in each site. Results: A total of 1,205 larval aquatic habitats were surveyed and yielded a total of 17,028 anopheline larvae, 26,958 culicine larvae and 1,189 pupae. Peaks in larval abundance occurred in all sites in March-May and August-October coinciding with the rainy seasons. Anopheles larvae were found in 52.4 % (n = 251) of aquatic habitats in Tororo, a site of high transmission, 41.9 % (n = 536) of habitats in Kanungu, a site with moderate malaria transmission, and 15.8 % (n=418) in Jinja, a site with low malaria transmission. The odds of finding Anopheles larvae was highest in rice fields compared to pools in both Tororo (odds ratio, OR = 4.21, 95% CI 1.22-14.56, p = 0.02) and Kanungu (OR= 2.14, 95% CI 1.12-4.07, p =0.02). In Kanungu, Anopheles larvae were less likely to be found in open drains compared to pools (OR = 0.15, 95% CI 0.03-0.72, p = 0.02) and river fringe (OR = 0.19, 95% CI 0.07-0.52, p = 0.001). Conclusions: These findings show that Anopheles larvae were common in areas of high and moderate transmission but were rare in areas of low transmission. Although Anopheles larvae were found in all types of water bodies, they were most common in rice fields and less common in open drains and on river fringes. Methods are needed to reduce the aquatic stages of anopheline mosquitoes in human-made habitats, particularly rice fields.

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Identification and characterization of Anopheles larval aquatic habitats at three sites of varying malaria transmission intensities in Uganda.

10.21203/rs.3.rs-24166/v1 ◽

2020 ◽

Author(s):

Alex K. Musiime ◽

David L. Smith ◽

Maxwell Kilama ◽

Geoffrey Otto ◽

Patrick Kyagamba ◽

...

Keyword(s):

Malaria Transmission ◽

Indoor Residual Spraying ◽

Binary Logistic Regression ◽

Rice Fields ◽

Sub Saharan Africa ◽

Larval Abundance ◽

Binary Logistic Regression Analysis ◽

Aquatic Habitats ◽

Sub Saharan ◽

A Site

Abstract Background: Over the last two decades, there has been remarkable progress in malaria control in sub-Saharan Africa, due mainly to the massive deployment of long-lasting insecticidal nets and indoor residual spraying. Despite these gains, it is clear that in many situations, additional interventions are needed to further reduce malaria transmission. Larval source management (LSM) is a potential supplementary measure that could be used to control malaria. However, prior to its roll-out, knowledge on ecology of larval aquatic habitats is required.Methods: Aquatic habitats colonized by Anopheles vectors were characterised at three sites of low, medium and high malaria transmission in Uganda from October 2011 to June 2016. Larval surveys were conducted along transects in each site and aquatic habitats described according to type and size. Anopheles mosquito larvae and pupae from the described habitats were sampled using standard dipping methods to determine larval densities. Larvae were identified as anopheline or culicine and counted. Pupae were not identified further. Binary logistic regression analysis was used to identify factors associated with the presence of Anopheles larvae in each site.Results: A total of 1,205 larval aquatic habitats were surveyed and yielded a total of 17,028 anopheline larvae, 26,958 culicine larvae and 1,189 pupae. Peaks in larval abundance occurred in all sites in March-May and August-October coinciding with the rainy seasons. Anopheles larvae were found in 52.4 % (n = 251) of aquatic habitats in Tororo, a site of high transmission, 41.9 % (n = 536) of habitats in Kanungu, a site with moderate malaria transmission, and 15.8 % (n=418) in Jinja, a site with low malaria transmission. The odds of finding Anopheles larvae was highest in rice fields compared to pools in both Tororo (odds ratio, OR = 4.21, 95% CI 1.22-14.56, p = 0.02) and Kanungu (OR= 2.14, 95% CI 1.12-4.07, p =0.02). In Kanungu, Anopheles larvae were less likely to be found in open drains compared to pools (OR = 0.15, 95% CI 0.03-0.72, p = 0.02) and river fringe (OR = 0.19, 95% CI 0.07-0.52, p = 0.001). Conclusions: These findings show that Anopheles larvae were common in areas of high and moderate transmission but were rare in areas of low transmission. Although Anopheles larvae were found in all types of water bodies, they were most common in rice fields and less common in open drains and on river fringes. Methods are needed to reduce the aquatic stages of anopheline mosquitoes in human-made habitats, particularly rice fields.

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Self-reported sexually transmitted infections among sexually active men in Ghana

BMC Public Health ◽

10.1186/s12889-021-11030-1 ◽

2021 ◽

Vol 21 (1) ◽

Author(s):

Abdul-Aziz Seidu ◽

Ebenezer Agbaglo ◽

Louis Kobina Dadzie ◽

Justice Kanor Tetteh ◽

Bright Opoku Ahinkorah

Keyword(s):

Sexually Transmitted Infections ◽

Binary Logistic Regression ◽

Sexual Partners ◽

Sub Saharan Africa ◽

Outcome Variable ◽

Binary Logistic Regression Analysis ◽

Sexually Active ◽

First Sex ◽

Sexually Transmitted ◽

Sub Saharan

Abstract Background In sub-Saharan Africa, sexually transmitted infections (STIs) other than HIV are major public health problems. This study, therefore, sought to assess the prevalence and factors associated with self-reported STIsamong sexually active men in Ghana. Methods Data from the 2014 Ghana demographic and health survey wereused to conduct the study. This research included a total of 3051 sexually active men aged 15–59 years. Self-reported STI was the outcome variable. The data were analyzed using both descriptive (frequencies and percentages) and inferential (binary logistic regression) analysis. Results The prevalence of self-reported STIs in the past 12 months preceding the survey was 6.0% (CI:4.7–6.8). Compared to men aged 45-59 years, those aged 25–34 (aOR = 2.96, CI: 1.64–5.35), 15–24 (aOR = 2.19, CI: 1.13–4.26), and 35–44 (aOR = 2.29, CI: 1.23–4.24) were more likely to report an STI. Men who had 2 or more sexual partners apart from their spouse were more likely to report an STI compared to those with no other partner apart from spouse (aOR = 4.24, CI: 2.52–7.14). However, those who had their first sex when they were 20 years and above (AOR = 0.66, CI: 0.47–0.93) and men who read newspaper/magazine had lower odds (aOR = 0.53, CI: 0.37–0.77) of reporting STIs compared to those who had sex below 20 and those who did not read newspaper/magazine respectively. Conclusion The study has revealed a relatively low prevalence of self-reported STI among sexually active men in Ghana. Sexually active men aged 25–34 years, those whose age at first sex is below 20 years and those with two or more sexual partners apart from their spouse had higher odds of reporting STIs. However, reading a newspaper was found to be positive in reducing the odds of reporting STIs. To reduce STIs among sexually active men in Ghana, it is important for health systems and stakeholders to consider these factors and put in place measures to mitigate those that put men at risk of STIs and encourage the adoption of the protective factors. Mass media can be used as a useful avenue for encouraging men to report STIs in order to avoid transmitting them to their partners.

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The dominant malaria vector, Anopheles funestus from rural south-eastern Tanzania, is more strongly resistant to insecticides than Anopheles arabiensis

10.21203/rs.3.rs-19762/v1 ◽

2020 ◽

Cited By ~ 1

Author(s):

Polius Gerazi Pinda ◽

Claudia Eichenberger ◽

Halfan S Ngowo ◽

Dickson S Msaky ◽

Said Abbasi ◽

...

Keyword(s):

Malaria Transmission ◽

Pyrethroid Resistance ◽

Mosquito Species ◽

Anopheles Funestus ◽

Indoor Residual Spraying ◽

Sub Saharan Africa ◽

Malaria Vectors ◽

Insecticide Treated Nets ◽

South Eastern ◽

Sub Saharan

Abstract Background: Long-lasting insecticide-treated nets (LLINs) and indoor residual spraying (IRS) have greatly reduced malaria transmission in sub-Saharan Africa, but are threatened by insecticide resistance in dominant malaria vectors. In south-eastern Tanzania, pyrethroid-resistant Anopheles funestus now transmit more than 80% of malaria infections even in villages where the species occurs at far lower densities than other vectors such as Anopheles arabiensis.Methods: To better understand the dominance of An. funestus in these settings and improve options for its control, this study compared intensities of resistance between females of this species and those of An. arabiensis , using WHO assays with 1×, 5× and 10× insecticide doses. Additional tests were done to assess the reversibility of such resistance using synergists. The mosquitoes were collected from villages across two districts in south-eastern Tanzania.Findings: Both species were resistant to the two pyrethroids (permethrin and deltamethrin) and the organochloride (DDT) but susceptible to the organophosphate (pirimiphos-methyl) at standard baseline doses (1×). However, An. funestus as opposed to An. arabiensis was also resistant to the carbamate (bendiocarb) at standard doses (1×). An. funestus showed strong resistance to pyrethroids, surviving the 5× doses and 10× doses except in one village. Pre-exposure to the synergist, piperonyl butoxide (PBO), reversed the pyrethroid-resistance in both An. arabiensis and An. funestus achieving mortalities >98%, except for An. funestus from two villages for which permethrin-associated mortalities exceeded 90% but not 98%.Conclusions : In these communities where An. funestus now dominates malaria transmission, the species also displays much stronger resistance to pyrethroids than its counterpart, An. arabiensis, and can readily survive more classes of insecticides, including carbamates. The resistance to pyrethroids in both mosquito species appears to be mostly metabolic and can be reversed significantly using synergists such as PBO. These findings may explain the continued persistence and dominance of An. funestus despite widespread use of pyrethroid-treated LLINs, and will also inform future choices of interventions to tackle malaria transmission in this area and other similar settings. Such interventions may include PBO-based LLINs or improved IRS with compounds such as organophosphates against which the vectors are still susceptible.

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An increasing role of pyrethroid-resistant Anopheles funestus in malaria transmission in the Lake Zone, Tanzania

Scientific Reports ◽

10.1038/s41598-021-92741-8 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Nancy S. Matowo ◽

Jackline Martin ◽

Manisha A. Kulkarni ◽

Jacklin F. Mosha ◽

Eliud Lukole ◽

...

Keyword(s):

Malaria Transmission ◽

Anopheles Funestus ◽

Sub Saharan Africa ◽

North West ◽

Vector Population ◽

Lake Zone ◽

Sub Saharan ◽

Long Lasting Insecticidal Nets ◽

Study District

AbstractAnopheles funestus is playing an increasing role in malaria transmission in parts of sub-Saharan Africa, where An. gambiae s.s. has been effectively controlled by long-lasting insecticidal nets. We investigated vector population bionomics, insecticide resistance and malaria transmission dynamics in 86 study clusters in North-West Tanzania. An. funestus s.l. represented 94.5% (4740/5016) of all vectors and was responsible for the majority of malaria transmission (96.5%), with a sporozoite rate of 3.4% and average monthly entomological inoculation rate (EIR) of 4.57 per house. Micro-geographical heterogeneity in species composition, abundance and transmission was observed across the study district in relation to key ecological differences between northern and southern clusters, with significantly higher densities, proportions and EIR of An. funestus s.l. collected from the South. An. gambiae s.l. (5.5%) density, principally An. arabiensis (81.1%) and An. gambiae s.s. (18.9%), was much lower and closely correlated with seasonal rainfall. Both An. funestus s.l. and An. gambiae s.l. were similarly resistant to alpha-cypermethrin and permethrin. Overexpression of CYP9K1, CYP6P3, CYP6P4 and CYP6M2 and high L1014S-kdr mutation frequency were detected in An. gambiae s.s. populations. Study findings highlight the urgent need for novel vector control tools to tackle persistent malaria transmission in the Lake Region of Tanzania.

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Near-infrared, mid-infrared or combined diffuse reflectance spectroscopy for assessing soil fertility in rice fields in sub-Saharan Africa

Geoderma ◽

10.1016/j.geoderma.2019.06.043 ◽

2019 ◽

Vol 354 ◽

pp. 113840 ◽

Cited By ~ 4

Author(s):

Jean-Martial Johnson ◽

Elke Vandamme ◽

Kalimuthu Senthilkumar ◽

Andrew Sila ◽

Keith D. Shepherd ◽

...

Keyword(s):

Soil Fertility ◽

Diffuse Reflectance ◽

Near Infrared ◽

Diffuse Reflectance Spectroscopy ◽

Reflectance Spectroscopy ◽

Rice Fields ◽

Sub Saharan Africa ◽

Mid Infrared ◽

Sub Saharan

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Prevalence of child marriage and its impact on fertility outcomes in 34 sub-Saharan African countries

BMC International Health and Human Rights ◽

10.1186/s12914-019-0219-1 ◽

2019 ◽

Vol 19 (1) ◽

Cited By ~ 6

Author(s):

Sanni Yaya ◽

Emmanuel Kolawole Odusina ◽

Ghose Bishwajit

Keyword(s):

Pregnancy Termination ◽

Binary Logistic Regression ◽

Adverse Outcomes ◽

Sub Saharan Africa ◽

Child Marriage ◽

Modern Contraceptive ◽

Contraceptive Methods ◽

African Countries ◽

Sub Saharan ◽

Children Ever Born

Abstract Background The issue of child marriage is a form of human rights violation among young women mainly in resource-constrained countries. Over the past decades, child marriage has gained attention as a threat to women’s health and autonomy. This study explores the prevalence of child marriage among women aged 20–24 years in sub-Saharan Africa countries and examines the association between child marriage and fertility outcomes. Methods Latest DHS data from 34 sub-Saharan African countries were used in this study. Sixty thousand two hundred and fifteen women aged 20–24 years were included from the surveys conducted 2008–2017. The outcome variables were childbirth within the first year of marriage (early fertility), first preceding birth interval less than 24 months (rapid repeat of childbirth), unintended pregnancy, lifetime pregnancy termination, the use of modern contraceptive methods, lifetime fertility and any childbirth. The main explanatory variable was child marriage (< 18 years) and the associations between child marriage and fertility outcomes were examined from the ever-married subsample to estimate odds ratios (ORs) and 95% CIs using binary logistic regression models. Results In the study population, the overall prevalence of women who experience child marriage was 54.0% while results showed large disparities across sub-Saharan African countries ranging from 16.5 to 81.7%. The prominent countries in child marriage were; Niger (81.7%), Chad (77.9%), Guinea (72.8%), Mali (69.0%) and Nigeria (64.0%). Furthermore, women who experience child marriage were 8.00 times as likely to have ≥3 number of children ever born (lifetime fertility), compared to women married at ≥18 years (OR = 8.00; 95%CI: 7.52, 8.46). Women who experience child marriage were 1.13 times as likely to use modern contraceptive methods, compared to adult marriage women (OR = 1.13; 95%CI: 1.09, 1.19). Those who married before the legal age were 1.27 times as likely to have lifetime terminated pregnancy, compared to women married at ≥18 years (OR = 1.27; 95%CI: 1.20, 1.34). Also women married at < 18 years were more likely to experience childbirth, compared to women married later (OR = 5.83; 95%CI: 5.45, 6.24). However, women married at < 18 years had a reduction in early childbirth and a rapid repeat of childbirth respectively. Conclusion Implementing policies and programmmes against child marriage would help to prevent adverse outcomes among women in sub-Saharan Africa. Also, social change programmes on child-marriage would help to reduce child marriage, encourage the use of modern contraceptive, which would minimize lifetime terminated pregnancy and also children ever born.

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