Annual MDA with a combination of Ivermectin and Albendazole is recommended for the control of LF in African countries which are co-endemic for onchocerciasis (8).
Successful elimination of LF based on the MDA strategy relies on maintaining a high treatment coverage to reduce the worm burden in humans and hence the onwards transmission (9). However, attaining and maintaining high treatment coverage has been a challenge in many LF control programmes globally (10).
Given that the required duration of MDA is based on the estimated reproductive lifespan of the adult worm, at least five rounds of MDA with a minimum coverage of 65% of the total population is considered to be adequate in order to reduce microfilariae to a level at which transmission will end without further interventions(11).
Elimination of LF as a public health problem is operationally defined as reducing infection to levels at which transmission is no longer sustainable and ensuring the availability of a WHO-recommended basic package of care to manage lymphoedema and hydrocele. The following measurable elimination thresholds must be demonstrated before stopping MDA: (i) microfilaraemia prevalence of less than 1% or antigenaemia prevalence of less than 2% in sentinel and spot-check surveys; and (ii) incident infection below 1% or 2% measured during the transmission assessment survey (12).
At the turn of the 20th century, it was estimated that 120 million people were infected with L globally and more than one billion were at risk of infection. A strategy of MDA, following the 1997 World Health Assembly resolution to eliminate LF, has led to one of the most ambitious and successful interventions against a neglected tropical disease. Under sufficient level of intervention coverage, transmission of LF can be interrupted within five years (13).
Based on WHO guideline an “effective MDA round” or reaching “effective coverage” during an MDA round is defined by epidemiological coverage of at least 65% in an implementation unit (12) and the current validation survey in the Itang special district was higher than the percentage set by the WHO as the coverage was 81.5% in the indicated region.
An integrated coverage validation survey in Togo showed that more than 86% of the respondents reported that they took the drugs of lymphatic filariasis which is higher than the reported coverage in this survey (14).
A median reported treatment coverage in Ghana over a period of a decade from 2000-2010 reported the coverage to be 77-80% in the above indicated period (15) and another coverage validation survey in Togo showed >88% of persons in each survey conducted 1, 6 and 12 months after the MDA indicated they were offered medication during the MDA and essentially the same proportion reported swallowing all the MDA medications they were offered (16). A lymphatic filariasis treatment validation survey in Kenya which uses a strategy of community directed with health system involvement showed coverage of 88%(17).
Treatment coverage and community compliance are important factors for successful LF elimination through the MDA strategy. It has been shown that in areas with high pre-MDA levels of infection, maintaining high drug intake during MDA is crucial in order to reach the elimination goal within a reasonable time frame (18).
A study conducted in Southeast Asia showed that the number of people requiring mass drug administration fell from 1.41 billion in 2011 to 856 million in 2016.It is expected that mass administration will no longer be required when the prevalence of infection has been reduced to low levels, such as microfilariae in <1% of the population or antigenaemia in <2% of the population (19).
Integrated delivery of community-based public health services demonstrated a high absolute post-intervention coverage. Programs and governments are increasingly integrating service distribution to streamline delivery of a variety of services and reduce costs (20) and the mass drug administration survey in Ethiopia has been given in integrated manner since its inception in 2013 and showed an improvement in coverage.
When comparing the coverage of Ivermectin and Albendazole for lymphatic filariasis treatment the drugs offered was significantly higher in children attending school than those not attending school (p<0.001) as the treatment strategy all over the country is mainly in primary schools while integrated MDAs together with STH and SCH also takes place in the community, but enrolled children have better information about the MDA and have high probability of taking the drugs during the mass drug administrations as non-enrolled children are highly likely for not being around the drug distribution sites during MDA dates .
The coverage in school age children (5-14) shows significant difference with treatment coverage in individuals aged 15 and above (p<0.001) in the last mass drug administration campaign and this fact can be explained by the fact that most of the respondents were school age children and that there was a wrong assumption that the treatment is not given for adults while the treatment strategy include all individuals aged 5 and above and other reasons were also considered such as change of living area and not being around during the mass drug administration.
The main reason given for not taking the drugs was not being around during the campaigns with a percentage value of 37.2 and a similar study in Tanzania showed that this is the main reason for not taking the preventive chemotherapy (8) and the same study showed the coverage of lymphatic filariasis treatment to be 51.6% and 57.4% for two separate coverage validation survey conducted in 2011 and 2015 G.C which is considerably lower than our finding.
Another study in Nigeria showed that among the very few that refused treatment, most did so because of fear or worry rather than personal experience of adverse events (21).
There were some limitations for this study such as missing some respondents in the household as the survey sites were remote kebeles and the main source of income for the household is farming and the members of the house may not be around during the data collection as they were in the field whereby the field may be farther from their living area. Another limitation of the study was that it included only a single district that distribute drugs in integrated treatment strategy and it would have been better if more districts were included to compare the coverage in different districts of the country and better understand the geographical coverage of the country.