Does the relationship of Community Drug Distributors to the individuals they treat with Ivermectin affect distribution success in Cameroon and Uganda, 2004-2005 Open Access

Torre, Lisandro (2012)

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Background: Onchocerciasis, also known as river blindness, has been targeted for elimination because humans are the only reservoir, and ivermectin treatment is cost effective and readily available. Ivermectin control programs are often evaluated at the country level and little is known about the community drug distributors (CDDs) themselves. The kinship enhanced community drug distribution program was developed to address the issue of sustainability. The long-term sustainability of the programs depends on the CDDs because ultimately they are responsible for distributing ivermectin to their communities at high coverage levels for many years.

Objectives: This thesis explores how delivering ivermectin to kinship groups effects treatment coverage in Cameroon and Uganda and whether or not the effect has been the same in males and females. This paper will fill in the knowledge gaps by determining whether a CDD is more likely to reach the 90% distribution target if over 50% of the people he or she distributed ivermectin to were related to the CDD. Additionally, this thesis will look at whether there are differences between Cameroon and Uganda and males and females.

Methods: Surveys from 1,636 CDDs in Cameroon and Uganda were analyzed using a multivariable regression model was used that considered treatment coverage as the outcome variable. The model was a logistic model to determine whether a CDD delivering ivermectin to his or her kinship group is associated with 90% treatment coverage for an individual distributor. The model also looked to see if the factors are the same or different in Cameroon and Uganda.

Results: After controlling for country, sex, number of households distributed, supervision, age, significant effect modification was found between country and relationship. There was also significant effect modification between sex and relationship. The significant interaction terms indicate that the effect of relationship to the outcome is different depending on whether the CDD is in Uganda or Cameroon and different depending on whether the CDD is male or female.

Conclusion: There is a difference on the effect of distributing to a majority kin that depends on whether the CDD is from Cameroon or Uganda and male or female.

Table of Contents

Table of Contents
Literature Review...1

Disease Background...2
Epidemiology of Onchocerciasis...2


Transmission Cycle...6
Diagnosis and Community Prevalence...8
Onchocerciasis Control Programs in Africa...13

Programs before Ivermectin...13
Ivermectin Distribution Programs...14
Kinship Enhanced CDTI...16


Software and Data Analysis Plan...21
Establishing Initial Model...22
Collinearity Assessment...24
Assessing Interaction...24


Demographic Results...26
Final Model...28
Odds ratio estimates...28

Future Directions...31
Overall Conclusion...33

Table 1: Demographic characteristics of community drug distributors in Cameroon and Uganda, 2004-2005...39
Table 2: Regression coefficients and confidence intervals for variables in the final model and by country with significant p-values in bold...40
Table 3a: Odds ratios for the effect of relationship in strata for country and sex...41
Table 3b: 95% Confidence Intervals for the odds ratio for the effect of relationship in strata for country and sex...41


IRB Exemption...43
Community Drug Distributor Survey...44

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