Geospatial modeling of pre-intervention prevalence of Onchocerca volvulus infection in Ethiopia as an aid to onchocerciasis elimination

Background Onchocerciasis is a neglected tropical and filarial disease transmitted by the bites of blackflies, causing blindness and severe skin lesions. The change in focus for onchocerciasis management from control to elimination requires thorough mapping of pre-control endemicity to identify areas requiring interventions and to monitor progress. Onchocerca volvulus infection prevalence in sub-Saharan Africa is spatially continuous and heterogeneous, and highly endemic areas may contribute to transmission in areas of low endemicity or vice-versa. Ethiopia is one such onchocerciasis-endemic country with heterogeneous O. volvulus infection prevalence, and many districts are still unmapped despite their potential for O. volvulus infection transmission. Methodology/Principle findings A Bayesian geostatistical model was fitted for retrospective pre-intervention nodule prevalence data collected from 916 unique sites and 35,077 people across Ethiopia. We used multiple environmental, socio-demographic, and climate variables to estimate the pre-intervention prevalence of O. volvulus infection across Ethiopia and to explore their relationship with prevalence. Prevalence was high in southern and northwestern Ethiopia and low in Ethiopia's central and eastern parts. Distance to the nearest river (-0.015, 95% BCI: -0.025 - -0.005), precipitation seasonality (-0.017, 95% BCI: -0.032 - -0.001), and flow accumulation (-0.042, 95% BCI: -0.07 - -0.019) were negatively associated with O. volvulus infection prevalence, while soil moisture (0.0216, 95% BCI: 0.014 - 0.03) was positively associated. Conclusions/Significance Infection distribution was correlated with habitat suitability for vector breeding and associated biting behavior. The modeled pre-intervention prevalence can be used as a guide for determining priority for intervention in regions of Ethiopia that are currently unmapped, most of which have comparatively low infection prevalence.

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Travel-time, bikes, and HIV elimination in Malawi: a geospatial modeling analysis

10.1101/2020.09.01.20186072 ◽

2020 ◽

Author(s):

Laurence Palk ◽

Justin T Okano ◽

Luckson Dullie ◽

Sally Blower

Keyword(s):

Travel Time ◽

Rural Areas ◽

Hiv Treatment ◽

Sub Saharan Africa ◽

People Living With Hiv ◽

Travel Times ◽

Geospatial Modeling ◽

Healthcare Facilities ◽

Fast Tracking ◽

Sub Saharan

Background: UNAIDS has prioritized Malawi and 21 other countries in sub-Saharan Africa (SSA) for "fast-tracking" the end of their HIV epidemics. To achieve elimination requires treating 90% of people living with HIV (PLHIV); coverage is already fairly high (70-75%). However, many individuals in SSA have to walk to access healthcare. We use data-based geospatial modeling to determine whether the need to travel long distances to access treatment and limited transportation in rural areas are barriers to HIV elimination in Malawi. Additionally, we evaluate the effect on treatment coverage of increasing the availability of bicycles in rural areas. Methods: We build a geospatial model that we use to estimate, for every PLHIV, their travel-time to access HIV treatment if driving, bicycling, or walking. We estimate the travel-times needed to achieve 70% or 90% coverage. Our model includes a spatial map of healthcare facilities (HCFs), the geographic coordinates of residencies for all PLHIV, and an "impedance" map. We quantify impedance using data on road/river networks, land cover, and topography. Findings: To cross an area of one km2 in Malawi takes from ~60 seconds (driving on main roads) to ~60 minutes (walking in mountainous areas); ~80% of PLHIV live in rural areas. At ~70% coverage, HCFs can be reached within: ~45 minutes if driving, ~65 minutes if bicycling, and ~85 minutes if walking. Increasing coverage above ~70% will become progressively more difficult. To achieve 90% coverage, the travel-time for many PLHIV (who have yet to initiate treatment) will be almost twice as long as those currently on treatment. Increasing bicycle availability in rural areas reduces round-trip travel-times by almost one hour (in comparison with walking), and could substantially increase coverage levels. Interpretation: Geographic inaccessibility to treatment coupled with limited transportation in rural areas are substantial barriers to reaching 90% coverage in Malawi. Increased bicycle availability could help eliminate HIV. Funding: National Institute of Allergy and Infectious Diseases

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Challenges of Human Papillomavirus Infection and Associated Diseases in Low-Resource Countries

Archives of Pathology & Laboratory Medicine ◽

10.5858/arpa.2017-0565-ra ◽

2018 ◽

Vol 142 (6) ◽

pp. 696-699 ◽

Cited By ~ 3

Author(s):

Michael Chukwugoziem Nweke ◽

Clement Abu Okolo ◽

Yara Daous ◽

Olukemi Ayotunde Esan

Keyword(s):

Human Papillomavirus ◽

High Risk ◽

Developed Countries ◽

Hpv Infection ◽

Sub Saharan Africa ◽

Morbidity And Mortality ◽

Infection Prevalence ◽

Screening Programs ◽

Low Resource ◽

Sub Saharan

Context.— The prevalence of human papillomavirus (HPV) infection varies worldwide. The high-risk viruses are usually associated with cancers of the cervix, vagina, and vulva in women, cancer of the penis in men, and cancers of the anus, tonsils, oropharynx, and base of the tongue in both sexes. Objectives.— To review literature about the challenges and burden associated with HPV infection in low-resource (ie, developing) countries, focusing on sub-Saharan Africa. To review the prevention, incidence, prevalence, morbidity, and mortality of HPV infections in sub-Saharan Africa. To review the therapy and management of HPV infections in low-resource countries in comparison to developed countries. Data Sources.— Peer-reviewed literature and experience of some of the authors. Conclusions.— Sub-Saharan Africa has high HPV infection prevalence rates, with predominance of high-risk subtypes 16, 18, and 45. The difficulty of access to health care has led to higher morbidity and mortality related to HPV-related cancers. Improvement in screening programs will help in monitoring the spread of HPV infections. Survival studies can be more informative if reliable cancer registries are improved. HPV vaccination is not yet widely available and this may be the key to curtailing the spread of HPV infections in resource-poor countries.

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Acaciella angustissima (Mill.) Brit. & Rose: Botanical Features, Distribution, Medicinal and Pharmacological Properties -

Journal of Pharmacy and Nutrition Sciences ◽

10.29169/1927-5951.2020.10.06.2 ◽

2020 ◽

Vol 10 (6) ◽

pp. 325-330

Author(s):

Collen Musara ◽

Elizabeth Bosede Aladejana

Keyword(s):

Malignant Tumors ◽

Antimicrobial Effect ◽

Skin Lesions ◽

Sub Saharan Africa ◽

Small Tree ◽

Quantitative And Qualitative Research ◽

The Family ◽

Sub Saharan ◽

Method Approach

Acaciella angustissima (Mill.) Brit. & Rose is a multipurpose deciduous thornless shrub or small tree that belongs to the family Fabaceae and subfamily Mimosoideae. This study aimed to explore A. angustissima, a leguminous shrub with medicinal, ecological and industrial potential. A mixed-method approach, which included consolidating quantitative and qualitative research, was utilized to put together the review with the main focus being on sub-Saharan Africa. However, case studies and literature from South Africa were also utilized. A. angustissima is a good source of phenolic compounds. It is used to relieve painful toothache, rheumatism, skin lesions, bloody diarrhea and mucoid diarrhea. It also displays a mild antimicrobial effect and has the ability to inhibit growth in malignant tumors. The study acknowledged Acaciella angustissima as an important agroforestry tree species that improve the quality of life of resource-poor farmers, reducing poverty and promoting sustainability of the natural resources base and economic growth

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Spatiotemporal mapping of malaria prevalence in Madagascar using routine surveillance and health survey data

Scientific Reports ◽

10.1038/s41598-020-75189-0 ◽

2020 ◽

Vol 10 (1) ◽

Author(s):

Rohan Arambepola ◽

Suzanne H. Keddie ◽

Emma L. Collins ◽

Katherine A. Twohig ◽

Punam Amratia ◽

...

Keyword(s):

Survey Data ◽

Malaria Prevalence ◽

Incidence Rates ◽

Sub Saharan Africa ◽

Cross Sectional ◽

Prevalence Data ◽

Nationally Representative ◽

Sub Saharan ◽

Lower Transmission ◽

Case Data

Abstract Malaria transmission in Madagascar is highly heterogeneous, exhibiting spatial, seasonal and long-term trends. Previous efforts to map malaria risk in Madagascar used prevalence data from Malaria Indicator Surveys. These cross-sectional surveys, conducted during the high transmission season most recently in 2013 and 2016, provide nationally representative prevalence data but cover relatively short time frames. Conversely, monthly case data are collected at health facilities but suffer from biases, including incomplete reporting and low rates of treatment seeking. We combined survey and case data to make monthly maps of prevalence between 2013 and 2016. Health facility catchment populations were estimated to produce incidence rates from the case data. Smoothed incidence surfaces, environmental and socioeconomic covariates, and survey data informed a Bayesian prevalence model, in which a flexible incidence-to-prevalence relationship was learned. Modelled spatial trends were consistent over time, with highest prevalence in the coastal regions and low prevalence in the highlands and desert south. Prevalence was lowest in 2014 and peaked in 2015 and seasonality was widely observed, including in some lower transmission regions. These trends highlight the utility of monthly prevalence estimates over the four year period. By combining survey and case data using this two-step modelling approach, we were able to take advantage of the relative strengths of each metric while accounting for potential bias in the case data. Similar modelling approaches combining large datasets of different malaria metrics may be applicable across sub-Saharan Africa.

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Re-assessing the global prevalence and distribution of lymphatic filariasis

Parasitology ◽

10.1017/s0031182000066646 ◽

1996 ◽

Vol 112 (4) ◽

pp. 409-428 ◽

Cited By ~ 304

Author(s):

E. Michael ◽

D. A. P. Bundy ◽

B. T. Grenfell

Keyword(s):

Lymphatic Filariasis ◽

Sub Saharan Africa ◽

Empirical Relationships ◽

Prevalence Data ◽

Helminth Infections ◽

Gender And Age ◽

Disease Surveys ◽

Sub Saharan ◽

Geographically Targeted ◽

And Gender

SUMMARYThis paper estimates the global burden of lymphatic filariasis based on a review of the published literature on infection and disease surveys. A method for aggregating and projecting prevalence data from individual studies to national, regional and global levels, which also facilitates the estimation of gender and age-specific burdens, is presented. The method weights in favour of the larger, and hence presumbably more reliable, studies and relies on estimated empirical relationships between gender, age, infection and disease in order to correct studies with incomplete data. The results presented here suggest that although the overall prevalence of filariasis cases is 2·0% globally (approximately totalling 119 million cases), the disease continues to be of considerable local importance, particularly in India and Sub-Saharan Africa. Estimates by age and gender clearly show that, unlike other helminth infections, filariasis is mainly a disease of the adult and older age-classes and appears to be more prevalent in males. This work suggests that the derivation of more accurate estimates of the burden of filariasis will require a better understanding of both the epidemiology and the spatial aspects of infection and disease. It also suggests that filariasis is preventable based on a geographically targeted strategy for control.

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Establishment of an in vitro culture system to study the developmental biology (growth, mating and nodule formation) of Onchocerca volvulus with implications for anti-onchocerca drug discovery and screening

10.1101/2020.06.25.170746 ◽

2020 ◽

Author(s):

Narcisse Victor T. Gandjui ◽

Abdel Jelil Njouendou ◽

Eric Njih Gemeg ◽

Fanny Fri Fombad ◽

Manuel Ritter ◽

...

Keyword(s):

Developmental Biology ◽

Drug Discovery ◽

Culture System ◽

Sub Saharan Africa ◽

Onchocerca Volvulus ◽

Nodule Formation ◽

Behavioural Pattern ◽

Culture Systems ◽

Sub Saharan

AbstractBackgroundInfections with Onchocerca volvulus nematodes remain a threat in Sub-Saharan Africa after two decades of ivermectin mass drug administration. Despite this effort, there is still an urgent need for understanding the parasite biology, especially mating behaviour and nodule formation, as well as development of more potent drugs that can clear the developmental (L3, L4, L5) and adult stages of the parasite and inhibit parasite’s reproductive and behavioural pattern.Methodology/Principal FindingsPrior to culture, freshly harvested O. volvulus L3 larvae from dissected Simulium were purified by centrifugation using a 30% Percoll solution to eliminate fly tissue debris and contaminants. Parasites were cultured in both cell-free and cell-based co-culture systems, and monitored daily by microscopic visual inspection. Exhausted culture medium was replenished every 2–3 days. The cell-free culture system supported the viability and motility of O. volvulus larvae for up to 84 days (DMEM–10%NCS), while the co-culture system (DMEM–10%FBS–LLC-MK2) extended the worm survival period to 315 days. Co-culture systems alone promoted the two consecutive parasite moults (L3 to L4 and L4 to L5) with highest moulting rates observed in DMEM–10%FBS–LLC-MK2 (69.2±30 %), while no moult was observed in DMEM–10%NCS–LEC condition. O. volvulus adult worms mating and even mating competitions were observed in DMEM–10% FBS –LLC-MK2 co-culture system. Early nodulogenesis was observed in both DMEM–10% FBS–LLC-MK2 and DMEM– 10%NCS–LLC-MK2 systems.Conclusions/SignificanceThe present study describes an in vitro system in which O. volvulus L3 larvae can be maintained in culture leading to the development of reproductive adult stages. Thus, this platform gives potential for the investigation of mating, mating competition and early stage of nodulogenesis of O. volvulus adult worms that can be used as additional targets for onchocercacidal drug screening.Author summaryRiver blindness affects people living in mostly remote and underserved rural communities in some of the poorest areas of the world. Although significant efforts have been achieved towards the reduction of disease morbidity, onchocerciasis still affect million of people in Sub-Saharan Africa. The current control strategy is the annual mass administration of ivermectin which have accumulated several drawbacks overtime: as the sole microfilaricidal action of the drug, very long treatment period (15-17 years) and reports of ivermectin losing its efficacy; Therefore, raising the urgent need for new onchocercacidal molecules. Our study has established an in vitro platform capable of supporting the growth and development of all developmental stages of O. volvulus (L3 infective stage, L4, L5 and adult worms), moreover the platform provided more insight on O. volvulus adult worms reproductive and behavioural pattern. Our findings provide more avenues for mass production of different parasite stages, the investigation of parasite developmental biology and the identification of targets for drug discovery against different phases of development of this filaria parasite

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Anaemia and severe malarial anaemia burden in febrile Gabonese children: a nine-year health facility based survey

The Journal of Infection in Developing Countries ◽

10.3855/jidc.3347 ◽

2013 ◽

Vol 7 (12) ◽

pp. 983-989 ◽

Cited By ~ 5

Author(s):

Marielle Karine Bouyou-Akotet ◽

Denise Patricia Mawili Mboumba ◽

Eric Kendjo ◽

Fanckie Mbadinga ◽

Nestor Obiang-Bekale ◽

...

Keyword(s):

Plasmodium Falciparum ◽

Malaria Diagnosis ◽

Malaria Prevalence ◽

Severe Anaemia ◽

Falciparum Infection ◽

Sub Saharan Africa ◽

Nutritional Deficiencies ◽

Infection Prevalence ◽

Severe Malarial Anaemia ◽

Sub Saharan

Introduction: Anaemia remains a major cause of poor health in children and pregnant women living in sub-Saharan Africa. Malaria is one of the main causes of anaemia in endemic countries. At the time of decreasing Plasmodium falciparum infection prevalence among children, it was essential to analyze the evolution of anaemia and severe malarial anaemia (SMA), the most frequent clinical manifestation of severe malaria, in Gabon. Methodology: Yearly recorded haemoglobin levels of febrile children aged below11 years, who benefitted from microscopic malaria diagnosis, were retrospectively analyzed to determine the evolution of anaemia and SMA prevalence throughout a nine-year period between 2000 and 2008. Results: Anaemia prevalence remained high both in P. falciparum-infected children (between 87.6% and 90.7%) and in uninfected children (between 73.5% and 82.6%). Although the risk of developing severe anaemia ranged between 1.9 [0.9-3.8] in 2000 and 3.0 [1.3-6.5] in 2007, SMA prevalence did not significantly change during the study period, varying from 6.0% to 8.0%. From 2001, the frequency of SMA was comparable between children younger than five years of age and children older than five years of age. Conclusions: The decreasing malaria prevalence previously observed in Gabon between 2000 and 2008 was not associated with a significant reduction of anaemia and SMA burden among children. Furthermore, other factors such as nutritional deficiencies, which may not be negligible, must be investigated in this vulnerable population

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Identifying cultural, climatic and temporal factors influencing Striga asiatica abundance within rice--maize systems in mid-west Madagascar

10.22541/au.162453823.37847249/v1 ◽

2021 ◽

Author(s):

Donald Scott ◽

Julie Scholes ◽

Meva Randrianjafizanaka ◽

Patrice Autfray ◽

Jean Randriamampianina ◽

...

Keyword(s):

Crop Production ◽

Management Practices ◽

Cultural Practices ◽

Sub Saharan Africa ◽

Long Distance ◽

Striga Asiatica ◽

Novel Technologies ◽

Precipitation Seasonality ◽

Sub Saharan ◽

Middle West

The parasitic weed genus Striga causes huge losses to crop production in sub-Saharan Africa, estimated to be in excess of $7 billion per year, affecting subsistence farmers who frequently lack access to novel technologies proposed for control. Effective Striga management therefore requires the development of strategies utilising existing cultural and management practices. We report a multi-year, landscape-scale monitoring project for Striga asiatica in the mid-west of Madagascar, undertaken over 2019-2020 with the aims of examining cultural, climatic and edaphic factors currently driving abundance and distribution. Long-distance transects were established across the middle-west region of Madagascar, over which Striga asiatica abundance in fields was estimated. Analysis of the data highlights the importance of crop variety and legumes in driving Striga density. Moreover, the dataset revealed significant effect of precipitation seasonality, mean temperature and altitude in determining abundance. A composite management index indicated the effect of a range of cultural practices on changes in Striga abundance. The findings support the assertion that single measures are not sufficient for the effective, long-term management of Striga. Furthermore, the composite score has potential as a significant guide of ISM control beyond the geographic range of this study.

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HBV and HCV infection among non-European Union immigrants in North-East Italy

Epidemiology and Infection ◽

10.1017/s0950268898001034 ◽

1998 ◽

Vol 121 (1) ◽

pp. 179-183 ◽

Cited By ~ 17

Author(s):

M. CHIARAMONTE ◽

A. PUPO ◽

T. MENEGON ◽

V. BALDO ◽

R. MALATESTA ◽

...

Keyword(s):

European Union ◽

Host Population ◽

Hcv Infection ◽

Sub Saharan Africa ◽

Infection Prevalence ◽

Region Of Origin ◽

North East ◽

B Virus ◽

The Status ◽

Sub Saharan

The status of hepatitis B virus (HBV) and hepatitis C virus (HCV) infection among non-European Union (non-EU) immigrants in North-East Italy was evaluated. Among the 1683 individuals tested the prevalence of HBsAg was 8·9% (150 subjects) and of HBV antibodies (anti-HBc with/without anti-HBs) was 38·9% (654 subjects). The distribution of HBV serological markers showed significant differences according to region of origin; the highest prevalence of infection (76·9%) and carriage (16·1%) was found in immigrants from sub-Saharan Africa. Among the 933 individuals screened for HCV infection, prevalence of antibody was much lower (0·9%) than that observed in the Italian general population (3·2–12·6%). The large number of HBV carriers among immigrants could increase the number of new adult infections due to life-style habits or professional risks in the host population. In contrast, the risk of HCV spread from non-EU immigrants is very low.

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