Impact of five annual rounds of mass drug administration with ivermectin on onchocerciasis in Sierra Leone

Background:Onchocerciasis is endemic in 12 of the 14 health districts of Sierra Leone.Good treatment coverage of community-directed treatment with ivermectin was achieved between 2005 and 2009 after the 11-year civil conflict.Sentinel site surveys were conducted in 2010 to evaluate the impact of five annual rounds of ivermectin distribution.Methods:In total,39 sentinel villages from hyper-and meso-endemic areas across the 12 endemic districts were surveyed using skin snips in 2010.Results were analyzed and compared with the baseline data from the same 39 villages.Results:The average microfilaridermia(MF)prevalence across 39 sentinel villages was 53.10%at baseline.The MF prevalence was higher in older age groups,with the lowest in the age group of 1-9 years(11.00%)and the highest in the age group of 40-49 years(82.31%).Overall mean MF density among the positives was 28.87 microfilariae(mf)/snip,increasing with age with the lowest in the age group of 1-9 years and the highest in the age group of 40-49 years.Males had higher MF prevalence and density than females.In 2010 after five rounds of mass drug administration,the overall MF prevalence decreased by 60.26%from 53.10%to 21.10%;the overall mean MF density among the positives decreased by 71.29%from 28.87 mf/snip to 8.29 mf/snip;and the overall mean MF density among all persons examined decreased by 88.58%from 15.33 mf/snip to 1.75 mf/snip.Ten of 12 endemic districts had>50%reduction in MF prevalence.Eleven of 12 districts had≥50%reduction in mean MF density among the positives.Conclusions:A significant reduction of onchocerciasis MF prevalence and mean density was recorded in all 12 districts of Sierra Leone after five annual MDAs with effective treatment coverage.The results suggested that the onchocerciasis elimination programme in Sierra Leone was on course to reach the objective of eliminating onchocerciasis in the country by the year 2025.Annual MDA with ivermectin should continue in all 12 districts and further evaluations are needed across the country to assist the NTDP with programme decision making.

Progress towards onchocerciasis elimination in the participating countries of the African Programme for Onchocerciasis Control: epidemiological evaluation results

Background:The African Programme for Onchocerciasis Control(APOC)was created in 1995 to establish community-directed treatment with ivermectin(CDTi)in order to control onchocerciasis as a public health problem in 20 African countries that had 80%of the global disease burden.When research showed that CDTi may ultimately eliminate onchocerciasis infection,APOC was given in 2008 the additional objective to determine when and where treatment can be safely stopped.We report the results of epidemiological evaluations undertaken from 2008 to 2014 to assess progress towards elimination in CDTi areas with≥6 years treatment.Methods:Skin snip surveys were undertaken in samples of first-line villages to determine the prevalence of O.volvulus microfilariae.There were two evaluation phases.The decline in prevalence was evaluated in phase 1A.Observed and model-predicted prevalences were compared after correcting for endemicity level and treatment coverage.Bayesian statistics and Monte Carlo simulation were used to classify the decline in prevalence as faster than predicted,on track or delayed.Where the prevalence approached elimination levels,phase 1B was launched to determine if treatment could be safely stopped.Village sampling was extended to the whole CDTi area.Survey data were analysed within a Bayesian framework to determine if stopping criteria(overall prevalence<1.4%and maximum stratum prevalence<5%)were met.Results:In phase 1A 127665 people from 639 villages in 54 areas were examined.The prevalence had fallen dramatically.The decline in prevalence was faster than predicted in 23 areas,on track in another 23 and delayed in eight areas.In phase 1B 108636 people in 392 villages were examined in 22 areas of which 13 met the epidemiological criteria for stopping treatment.Overall,32 areas(25.4 million people)had reached or were close to elimination,18 areas(17.4 million)were on track but required more years treatment,and in eight areas(10.4 million)progress was unsatisfactory.Conclusions:Onchocerciasis has been largely controlled as a public health problem.Great progress has been made towards elimination which already appears to have been achieved for millions of people.For most APOC countries,nationwide onchocerciasis elimination is within reach.

Factors associated with coverage of praziquantel for schistosomiasis control in the communitydirect intervention (CDI) approach in Mali (West Africa)

Background:Despite the progress made in the control of Neglected Tropical Diseases(NTD),schistosome and soil-transmitted helminth infections are far from being effectively managed in many parts of the world.Chemotherapy,the key element of all control strategies,is faced with some difficulties in terms of access to treatment.Our study aims to describe the factors involved in the success or failure of the community-directed intervention(CDI)approach through control programmes,which aims to achieve consistent high coverage at affordable and sustainable costs in endemic areas.Methods:The CDI approach was carried out from December 2007 to October 2008 in ten villages of the district of Diéma,Mali.At inclusion,each child part of the study’s sample was interviewed and submitted for a physical examination.The study focused on:data collection,treatment of the eligible population,evaluation of the treatment coverage,performance of community drug distributors(CDDs),and the involvement and perception of populations.Results:A total of 8,022 eligible people were studied with a mean coverage rate of 76.7%.Using multiple regression,it was determined that receiving praziquantel as treatment was associated with five factors:belonging to the Fulani or Moorish ethnic minority versus the Bambara/Soninke,use of the central versus the house-to-house drug distribution mode,the ratio of the population to the number of CDDs,the lack of supervision and belonging to the age group of 15 years or above(p<0.05).As well as that,it was found that the presence of parallel community-based programmes(HIV,tuberculosis)that provide financial incentives for community members discouraged many CDDs(who in most cases are volunteers)to participate in the CDI approach due to a lack of incentives.Conclusions:The findings indicate that the success of the CDI approach depends on,amongst other things,the personal characteristics of the respondents,as well as on community factors.