P. Craig Withers

The Peculiar Epidemiology of Dracunculiasis in Chad

Dracunculiasis was rediscovered in Chad in 2010 after an apparent absence of 10 years. In April 2012 active village-based surveillance was initiated to determine where, when, and how transmission of the disease was occurring, and to implement interventions to interrupt it. The current epidemiologic pattern of the disease in Chad is unlike that seen previously in Chad or other endemic countries, i.e., no clustering of cases by village or association with a common water source, the average number of worms per person was small, and a large number of dogs were found to be infected. Molecular sequencing suggests these infections were all caused by Dracunculus medinensis. It appears that the infection in dogs is serving as the major driving force sustaining transmission in Chad, that an aberrant life cycle involving a paratenic host common to people and dogs is occurring, and that the cases in humans are sporadic and incidental.

Epidemiological and Entomological Evaluations after Six Years or More of Mass Drug Administration for Lymphatic Filariasis Elimination in Nigeria

The current strategy for interrupting transmission of lymphatic filariasis (LF) is annual mass drug administration (MDA), at good coverage, for 6 or more years. We describe our programmatic experience delivering the MDA combination of ivermectin and albendazole in Plateau and Nasarawa states in central Nigeria, where LF is caused by anopheline transmitted Wuchereria bancrofti. Baseline LF mapping using rapid blood antigen detection tests showed mean local government area (LGA) prevalence of 23% (range 4–62%). MDA was launched in 2000 and by 2003 had been scaled up to full geographic coverage in all 30 LGAs in the two states; over 26 million cumulative directly observed treatments were provided by community drug distributors over the intervention period. Reported treatment coverage for each round was ≥85% of the treatment eligible population of 3.7 million, although a population-based coverage survey in 2003 showed lower coverage (72.2%; 95% CI 65.5–79.0%). To determine impact on transmission, we monitored three LF infection parameters (microfilaremia, antigenemia, and mosquito infection) in 10 sentinel villages (SVs) serially. The last monitoring was done in 2009, when SVs had been treated for 7–10 years. Microfilaremia in 2009 decreased by 83% from baseline (from 4.9% to 0.8%); antigenemia by 67% (from 21.6% to 7.2%); mosquito infection rate (all larval stages) by 86% (from 3.1% to 0.4%); and mosquito infectivity rate (L3 stages) by 76% (from 1.3% to 0.3%). All changes were statistically significant. Results suggest that LF transmission has been interrupted in 5 of the 10 SVs, based on 2009 finding of microfilaremia ≥1% and/or L3 stages in mosquitoes. Four of the five SVs where transmission persists had baseline antigenemia prevalence of >25%. Longer or additional interventions (e.g., more frequent MDA treatments, insecticidal bed nets) should be considered for ‘hot spots’ where transmission is ongoing.

Dracunculiasis, Onchocerciasis, Schistosomiasis, and Trachoma

The four diseases discussed in this chapter (dracunculiasis, onchocerciasis, schistosomiasis, and trachoma) are among the officially designated “Neglected Tropical Diseases,” and each is also both the result of and a contributor to the poverty of many rural populations. To various degrees, they all have adverse effects on health, agricultural productivity, and education. The Carter Center decided to work on these health problems because of their adverse effect on the lives of poor people and the opportunity to help implement effective interventions. As a result of the global campaign spearheaded by the Carter Center since 1986, the extent of dracunculiasis has been reduced from 20 to five endemic countries and the number of cases reduced by more than 99%. We have helped administer nearly 20% of the 530 million Mectizan (ivermectin) doses for onchocerciasis, which is now being controlled throughout most of Africa, and is progressing toward elimination in the Americas. Since 1999, two Nigerian states have been using village‐based health workers originally recruited to work on onchocerciasis to also deliver mass treatment and health education for schistosomiasis and lymphatic filariasis. They now also distribute vitamin A supplements and bed nets to prevent malaria and lymphatic filariasis. Ethiopia aims to eliminate blinding trachoma in the Amhara Region of that highest‐endemicity country by 2012, already constructing more than 300,000 latrines and other complementary interventions. Because of the synergy between these diseases and poverty, controlling or eliminating the disease also reduces poverty and increases self‐reliance.

Nigeria's Triumph: Dracunculiasis Eradicated

This report describes how Nigeria, a country that at one time had the highest number of cases of dracunculiasis (Guinea worm disease) in the world, reduced the number of cases from more than 653,000 in 1988 to zero in 2009, despite numerous challenges. Village-based volunteers formed the foundation of the program, which used health education, cloth filters, vector control, advocacy for safe water, voluntary isolation of patients, and monitored program interventions and cases reported monthly. Other factors in the programs success were strong governmental support, advocacy by a former head of state of Nigeria, technical and financial assistance by The Carter Center, the U.S. Centers for Disease Control and Prevention, the United Nations Childrens Fund, the World Health Organization, and many other partners and donors. The estimated cost of the Nigerian program during 1988-2009 is

The Contributions of Onchocerciasis Control and Elimination Programs toward the Achievement of the Millennium Development Goals

37.5 million, not including funding for water supply projects or salaries of Nigerian governmental workers.

Contributions of the Guinea Worm Disease Eradication Campaign toward Achievement of the Millennium Development Goals

In 2000, 189 member states of the United Nations (UN) developed a plan for peace and development, which resulted in eight actionable goals known as the Millennium Development Goals (MDGs). Since their inception, the MDGs have been considered the international standard for measuring development progress and have provided a blueprint for global health policy and programming. However, emphasis upon the achievement of priority benchmarks around the “big three” diseases—namely HIV, tuberculosis (TB), and malaria—has influenced global health entities to disproportionately allocate resources. Meanwhile, several tropical diseases that almost exclusively impact the poorest of the poor continue to be neglected, despite the existence of cost-effective and feasible methods of control or elimination. One such Neglected Tropical Disease (NTD), onchocerciasis, more commonly known as river blindness, is a debilitating and stigmatizing disease primarily affecting individuals living in remote and impoverished areas. Onchocerciasis control is considered to be one of the most successful and cost-effective public health campaigns ever launched. In addition to improving the health and well-being of millions of individuals, these programs also lead to improvements in education, agricultural production, and economic development in affected communities. Perhaps most pertinent to the global health community, though, is the demonstrated effectiveness of facilitating community engagement by allowing communities considerable ownership with regard to drug delivery. This paper reviews the contributions that such concentrated efforts to control and eliminate onchocerciasis make to achieving select MDGs. The authors hope to draw the attention of public policymakers and global health funders to the importance of the struggle against onchocerciasis as a model for community-directed interventions to advance health and development, and to advocate for NTDs inclusion in the post 2015 agenda.

Dracunculiasis Eradication: And Now, South Sudan

Infectious diseases have influenced the biological, historical, and political development of the human species more than any other factor: from the outcome of wars to the success of empires, from the pace of technological advance to the structure of society [1]. Dracunculiasis (Guinea worm disease) was considered a mild affliction not warranting a widespread public health campaign. However, examination of the benefits of eradicating Guinea worm disease (GWD) reveals the effort is contributing to development, including contributions to certain Millennium Development Goals (MDGs) [2]. Given the use of the MDGs in the development of global health agendas, it is timely to consider the contributions of neglected tropical disease (NTD) programs, such as the Guinea Worm Eradication Program (GWEP), toward the achievement of the MDGs. The prevention of NTDs, and their cost-effective interventions, fuels long-term economic growth and development, and human advancement [3]. The effort to eradicate GWD is considered one of the most cost-effective health interventions available [2,4,5]. The authors provide evidence that concentrated efforts on eradication, elimination, and control of some NTDs can yield far-reaching results, and given these results, stimulate increased efforts toward NTD eradication, elimination, and control among public health advocates, global health entities, and donors. GWD is a disease of the poor, debilitating many in the most remote and disadvantaged communities in parts of sub-Saharan Africa, where potable water is limited and health care and education are lacking [6]. Endemic GWD transmission is an indicator of extreme poverty [6,7]. GWD is a preventable, painful, and incapacitating waterborne helminthic disease, which harms health, agriculture, school attendance, and overall quality of life for individuals and communities [7–9]. GWD is transmitted when humans drink water, usually from stagnant water sources, containing tiny copepods that have ingested larvae of the parasite. Once consumed, the digestive juices in the human stomach kill the copepods, allowing the larvae to be released and move to the intestinal wall where they migrate to connective tissues of the thorax. Male and female larvae mature and mate 60–90 days after infection. Symptoms appear 10–14 months later when the gravid adult female(s), measuring up to 70–100 cm long, emerges from the skin, causing a painful lesion [10]. When the emerging worm is exposed to water, she ejects hundreds of thousands of larvae into the water to continue the cycle. During emergence, an infected person can be incapacitated for an average of 8.5 weeks [10,11]. Although rarely fatal, GWD inflicts devastating pain and infection resulting in immobility [8,12]. The pain is so long-lasting that infected individuals may be incapacitated for up to three months during and after the Guinea worm (GW) emerges [11,13–15]. Other symptoms include nausea, vomiting, diarrhea, and dizziness; secondary bacterial infections can also occur and can lead to arthritis, tetanus, and permanent crippling [8]. There is no cure, vaccine, or immunity after infection [11]. Since there is no evidence that animals are reservoir hosts, the disease is deemed a good candidate for eradication [8]. The global eradication campaign began at the United States Centers for Disease Control and Prevention (CDC) in 1980 and was then adopted as a subgoal of the United Nations International Drinking-Water Supply and Sanitation Decade (1981–1990). In that same year, the decision-making body of the World Health Organization (WHO) adopted a resolution (WHA 34.25) recognizing the decade could be an opportunity to eliminate GWD. Since 1986, The Carter Center (TCC) has led the effort, with the help of the CDC, WHO, United Nations Children’s Fund (UNICEF), and many other donors and nongovernmental organizations, to assist national eradication efforts by governments of the countries where GWD is endemic [11]. The GWEP assists ministries of health (MOH) in each endemic country to provide GWD interventions. The GWEP is an eradication effort that relies heavily on behavioral change via health education and interventions. The GWEP has demonstrated that when people are given the proper tools and health education, cases decrease dramatically [16]. The most effective and cost-efficient way to prevent GWD is the promotion of its health campaign coupled with proper and consistent use of filters to remove the copepods from drinking water, case containment, and the application of ABATE, a safe chemical larvicide, to control the copepods [4,17–19]. GWD is an infectious disease categorized as a neglected tropical disease (NTD) [20]. NTDs are among the most common infectious diseases of the world’s poorest people [21,22]. An estimated 1.2 billion people are infected with one or more NTDs [23]. These individuals are among the billion people living on less than

Trachoma control as a vehicle toward international development and achievement of the millennium development goals.

1 per day, a population identified as the ‘‘bottom billion’’ [23]. NTDs are a group of parasitic, bacterial, and viral diseases that cause

Logistics of Guinea Worm Disease Eradication in South Sudan

This report summarizes the status of the global Dracunculiasis Eradication Program as of the end of 2012. Dracunculiasis (Guinea worm disease) has been eliminated from 17 of 21 countries where it was endemic in 1986, when an estimated 3.5 million cases occurred worldwide. Only 542 cases were reported from four countries in 2012, and 103 villages still had indigenous transmission. Most remaining cases were reported from the new Republic of South Sudan, whereas Chad, Ethiopia, and Mali each reported 10 cases or less. Political instability and insecurity in Mali may become the main obstacles to interrupting dracunculiasis transmission forever.

Dracunculiasis Eradication: Are We There Yet?

Caused by bacterial infection, trachoma is the leading infectious cause of blindness in the world and is currently endemic in approximately 53 countries. Estimates report that 2.2 million people are visually impaired as a result of trachoma, 1.2 million of whom are irreversibly blind, and another 7.3 million persons are living with the late, disabling stages of the disease [1]. Trachoma is exacerbated by poverty, unsanitary living conditions, crowding, and the eye-seeking fly Musca sorbens. The World Health Organization (WHO) has endorsed the SAFE strategy for trachoma control, which stands for surgery, antibiotics, facial cleanliness, and environmental changes. The latest reports indicate that at least 110 million people live in areas where trachoma is suspected to be endemic and implementation of SAFE is necessary [2]. In the late 1990s, member states of the World Health Assembly passed a resolution calling for the elimination of blinding trachoma as a public health problem by 2020 and established the Global Alliance for the Elimination of Trachoma by 2020 (GET2020) to support this goal. Since then, considerable efforts have been made at both the international and national levels to control and reduce trachoma transmission and prevalence [1]. In light of these recent efforts, experience and anecdotal evidence gathered by leaders in the field suggest that the interventions employed as part of the SAFE strategy might work beyond trachoma-specific end goals; specifically, the basic interventions provided through SAFE can foster development and reduce poverty at the household and community levels. Intuitively, the conjecture makes sense: reductions in disease burden should work to increase productivity and income, while improvements in water sanitation and hygiene (WASH) increase quality of life and improve overall health. Taken together, the interventions could break the cycle of poverty and stimulate development. Evidence from the literature in support of this claim (using the goals outlined by the United Nations [UN] Millennium Development Goals [MDGs] as a metric for development) is slim at best. While publications documenting the effectiveness of trachoma control in reducing trachoma burden are plentiful, studies measuring the impact of SAFE on development are less robust. A review of the present evidence base does prove to be hypothesis-generating, however. Analyzing each goal separately, there is a rational basis to support the argument that trachoma control works to improve development.