scholarly journals Patterns of epidemiology and control of onchocerciasis in West Africa

1997 ◽  
Vol 71 (2) ◽  
pp. 91-101 ◽  
Author(s):  
B. Boatin ◽  
D.H. Molyneux ◽  
J.M. Hougard ◽  
O.W. Christensen ◽  
E.S. Alley ◽  
...  
Keyword(s):  
West Africa ◽  
Vector Control ◽  
Control Strategies ◽  
Control Programme ◽  
Transmission Potential ◽  
The Public ◽  
And Control ◽  
Combined Impact ◽  
The Impact ◽  
Onchocerciasis Control

AbstractThis paper summarizes the work of the Onchocerciasis Control Programme (OCP) in West Africa, a programme which over a 22 year history has reduced the public health problems of blinding onchocerciasis in eleven countries of West Africa through vector control and, more recently, ivermectin distribution. The paper emphasizes the different approaches to control the programme has developed in the different parts of the programme area which have been determined by the epidemiology of the disease (savanna/forest form), the migratory characteristics of the vectors, intensity of the disease before commencement of treatment, the combined impact of vector control and ivermectin and the likelihood of infiltration of infective blackflies from outside the programme area. The programme has constantly monitored the impact of operations on the trends in prevalence, incidence, annual transmission potential, ocular morbidity and species of fly populations, and as a result, has identified areas where special interventions are required until the programme comes to an end in 2002. The paper illustrates the changes in intensity of infection as measured by community microfilarial load and annual transmission potential over the duration of the programme control activities. The paper also defines and justifies the control strategies in different areas and identifies areas for special interventions.

scholarly journals Onchocerciasis control in Ghana (1974–2016)

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Nana-Kwadwo Biritwum ◽  
Dziedzom K. de Souza ◽  
Odame Asiedu ◽  
Benjamin Marfo ◽  
Uche Veronica Amazigo ◽  
...  
Keyword(s):  
Confidence Interval ◽  
Vector Control ◽  
Control Strategy ◽  
Financial Support ◽  
Control Programme ◽  
Ivermectin Treatment ◽  
Mobile Community ◽  
The Mean ◽  
The Impact ◽  
Onchocerciasis Control

Abstract Background The control of onchocerciasis in Ghana started in 1974 under the auspices of the Onchocerciasis Control Programme (OCP). Between 1974 and 2002, a combination of approaches including vector control, mobile community ivermectin treatment, and community-directed treatment with ivermectin (CDTI) were employed. From 1997, CDTI became the main control strategy employed by the Ghana OCP (GOCP). This review was undertaken to assess the impact of the control interventions on onchocerciasis in Ghana between 1974 and 2016, since which time the focus has changed from control to elimination. Methods In this paper, we review programme data from 1974 to 2016 to assess the impact of control activities on prevalence indicators of onchocerciasis. This review includes an evaluation of CDTI implementation, microfilaria (Mf) prevalence assessments and rapid epidemiological mapping of onchocerciasis results. Results This review indicates that the control of onchocerciasis in Ghana has been very successful, with a significant decrease in the prevalence of infection from 69.13% [95% confidence interval) CI 60.24–78.01] in 1975 to 0.72% (95% CI 0.19–1.26) in 2015. Similarly, the mean community Mf load decreased from 14.48 MF/skin snip in 1975 to 0.07 MF/skin snip (95% CI 0.00–0.19) in 2015. Between 1997 and 2016, the therapeutic coverage increased from 58.50 to 83.80%, with nearly 100 million ivermectin tablets distributed. Conclusions Despite the significant reduction in the prevalence of onchocerciasis in Ghana, there are still communities with MF prevalence above 1%. As the focus of the GOCP has changed from the control of onchocerciasis to its elimination, both guidance and financial support are required to ensure that the latter goal is met.

Impact of parental onchocerciasis and intensity of transmission on development and persistence ofOnchocerca volvulusinfection in offspring: an 18 year follow-up study

Parasitology ◽  
2003 ◽  
Vol 127 (4) ◽  
pp. 327-335 ◽  
Author(s):  
A. K. KIRCH ◽  
H. P. DUERR ◽  
B. BOATIN ◽  
W. S. ALLEY ◽  
W. H. HOFFMANN ◽  
...  
Keyword(s):  
Associated Factors ◽  
Multiple Logistic Regression Analysis ◽  
Infection Intensity ◽  
Control Programme ◽  
Multiple Logistic Regression ◽  
Transmission Potential ◽  
Follow Up Study ◽  
The Impact ◽  
Onchocerciasis Control

This study analysed the impact and the extent by which parentalOnchocerca volvulusinfection, intensity of transmission ofO. volvulusinfective 3rd-stage larvae (L3) and anthropometric factors may influence the acquisition, development and persistence ofO. volvulusinfection in offspring. A total of 15 290 individuals in 3939 families with 9640 children were surveyed for microfilariae ofO. volvulus, and prevalence and level ofO. volvulusinfection in children aged 0 to 20 years from infected and non-infected parents were followed longitudinally for 18 years. Children fromO. volvulus-infected mothers had not only a substantially higher risk to become infected; they also acquired infection earlier in life and developed higher infection levels. Multiple logistic regression analysis showed that maternalO. volvulusinfection and children's age are the predominant predictors for patentO. volvulusinfection, while the intensity of transmission, measured by the annual transmission potential (ATP) ofO. volvulusL3, was less decisive. Longitudinal follow up of children showed that during vector control activities by the Onchocerciasis Control Programme (OCP) and in low-level transmission areas, infection persisted at higher levels in children fromO. volvulus-positive mothers. In summary, the dominant risk factor for children to become infected is maternal onchocerciasis, and also age-associated factors will strongly impact on the development of patentO. volvulusinfection in offspring.

Progress in controlling the reinvasion of windborne vectors into the western area of the Onchocerciasis Control Programme in West Africa

1990 ◽  
Vol 328 (1251) ◽  
pp. 731-750 ◽  
Keyword(s):  
West Africa ◽  
Vector Control ◽  
Sierra Leone ◽  
Control Programme ◽  
West African ◽  
Breeding Sites ◽  
Western Area ◽  
Monsoon Winds ◽  
First Time ◽  
Onchocerciasis Control

Since vector control began in 1975, waves of Simulium sirbanum and S. damnosum s.str ., the principal vectors of severe blinding onchocerciasis in the West African savannas, have reinvaded treated rivers inside the original boundaries of the Onchocerciasis Control Programme in West Africa. Larviciding of potential source breeding sites has shown that these ‘savanna’ species are capable of travelling and carrying Onchocerca infection for at least 500 km northeastwards with the monsoon winds in the early rainy season. Vector control has, therefore, been extended progressively westwards. In 1984 the Programme embarked on a major western extension into Guinea, Sierra Leone, western Mali, Senegal and Guinea-Bissau. The transmission resulting from the reinvasion of northern Cote d’Ivoire and Burkina Faso has been reduced by over 95%, but eastern Mali has proved more difficult to protect because of sources in both Guinea and Sierra Leone. Rivers in Sierra Leone were treated for the first time in 1989 and biting and transmission rates in Sierra Leone and Guinea fell by over 90%. Because of treatment problems in some complex rapids and mountainous areas, flies still reinvaded Mali, though biting rates were approximately 70% lower than those recorded before anti-reinvasion treatments started. It was concluded that transmission in eastern Mali has now been reduced to the levels required to control onchocerciasis.

The WHO Onchocerciasis Control Programme: Retrospect and prospects

1990 ◽  
Vol 328 (1251) ◽  
pp. 721-729 ◽  
Keyword(s):  
West Africa ◽  
Insecticide Resistance ◽  
Vector Control ◽  
Species Complex ◽  
Control Programme ◽  
Related Research ◽  
Simulium Damnosum ◽  
The Future ◽  
History Of ◽  
Onchocerciasis Control

The history of onchocerciasis control in Africa and the genesis of the WHO Onchocerciasis Control Programme in West Africa (OCP) are briefly reviewed. The importance of experience gained in anti-locust campaigns in helping to plan the OCP is stressed. Members of the Simulium damnosum species complex are the vectors of onchocerciasis, which OCP is controlling with insecticide treatments on the stretches of rivers where the Simulium breed. Migrations of flies have been responsible for reinfestations of controlled areas and the spread of insecticide resistance. The management of these problems and related research are described, but it is emphasized that despite setbacks OCP is achieving its aims. A strategy for the future is outlined: vector control supplemented by chemotherapy is expected to continue until the year 2004.

Integration of Renewable Energy in Refrigerated Warehouses

2015 ◽  
pp. 803-853
Author(s):  
Kostadin Fikiin ◽  
Borislav Stankov
Keyword(s):  
Solar Wind ◽  
Renewable Energy ◽  
Energy Supply ◽  
Energy Demand ◽  
Control Strategies ◽  
Public Awareness ◽  
Food Storage ◽  
Policy Makers ◽  
The Public ◽  
And Control

Refrigerated warehouses are large energy consumers and account for a significant portion of the global energy demand. Nevertheless the opportunity for integration of renewable resources in the energy supply of large cold storage facilities is very often unjustifiably neglected, whereas the employment of renewable energy for many other industrial and comfort applications is actively promoted and explored. In that context, the purpose of this chapter is to bridge the existing gap by raising the public awareness of stakeholders, researchers, practicing engineers and policy makers about the availability of a number of smart engineering solutions and control strategies to exploit renewables of different nature (solar, wind, geothermal, biogas, etc.) in the food storage sector, as well as by calling the readers' attention to the specialised knowledge in the matter, which has been published so far.

Introduction to pertussis transmission and epidemiological dynamics

Pertussis ◽  
2018 ◽  
pp. 6-25
Author(s):  
Pejman Rohani ◽  
Samuel V. Scarpino
Keyword(s):  
Control Strategies ◽  
Age Distribution ◽  
Population Level ◽  
Vaccine Uptake ◽  
Effective Control ◽  
Transmission Potential ◽  
Epidemic Period ◽  
The Impact ◽  
Pertussis Epidemiology

Resolving the long-term, population-level consequences of changes in pertussis epidemiology, arising from bacterial evolution, shifts in vaccine-induced immunity, or changes in surveillance, are key challenges for devising effective control strategies. This chapter reviews some of the key features of pertussis epidemiology, together with the underlying epidemiological principles that set the context for their interpretation. These include the relationship between the age distribution of cases and pertussis transmission potential, the impact of vaccine uptake on incidence, periodicity and age incidence, as well as spatially explicit recurrent pertussis epidemics and associated extinction frequency. This review highlights some of the predictable and consistent aspects of pertussis epidemiology (e.g. the systematic increase in the inter-epidemic period with the introduction of whole-cell vaccines) and a number of important heterogeneities, including variations in contemporary patterns of incidence and geographic spread.

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