#guinea worm

Comparing the Guinea Worm Eradication Campaign in Pakistan with the Malaria and Smallpox Eradication Campaigns

There were an estimated 3.5 million cases of dracunculiasis worldwide per year in 1986, but by 2024 there were only 14 reported human cases. This dramatic reduction was due to the guinea worm eradication program which started in 1980. Pakistan was the first country to completely eradicate guinea worm in 1993. Like the successful smallpox eradication program and unlike the less successful malaria eradication program, the Pakistan guinea worm eradication program was successful due to its ability to self-assess and change tactics when necessary. It pioneered several novel techniques that ended up being used in other countries’ guinea worm eradication programs. There were also biological characteristics of guinea worm and smallpox that made them easier to eradicate than malaria. It also empowered local people by providing them with knowledge.

Dracunculiasis is a disease caused by a nematode, Dracunculus medinensis. It is spread via drinking water contaminated with Cyclops copepods, a tiny invertebrate which carry Dracunculiasis larvae. Humans ingest the copepods and the larvae travel through the stomach or intestinal lining and into the abdominal cavity or retroperitoneal space. The mature female worms eventually migrate to the surface of the skin where they emerge through a blister. Due to the burning pain, people submerge their limbs in water where the larvae are released, beginning the cycle anew. (1) The mature female worm can reach up to a meter in length and has to be pulled out of the blister, which takes about 3 months and is a horrifically painful process. (2) The wound may also get infected. People are disabled for months, causing interruptions in childcare, economic productivity and education in addition to the pain. Dracunculiasis is largely a disease affecting poor rural areas, having been endemic in parts of Africa, the Middle East, Pakistan and India. It has been well known since antiquity, having been described by Galen and other Roman writers, and having been known in Western literature since the 17th century. It was generally of little interest to colonizing Europeans since it was seen as a disease only affecting poor people of color. (3) Before the global guinea worm eradication campaign began in 1980, there had been very little surveillance for cases, meaning exact estimates of case numbers were difficult. It has been estimated that there were about 3.5 million cases in 1986. (4)

The worldwide guinea worm eradication campaign began in 1980 as part of the World Health Organization’s International Drinking Water Supply and Sanitation Decade which spanned from 1981 to 1990. Since 1986 it has been led by the Carter Center which serves as the head of the campaign, working with the World Health Organization, the ministries of health of the endemic countries, the CDC, UNICEF, and volunteer health workers. (4) The recent success of the smallpox eradication campaign brought the idea of guinea worm eradication to light. Dracunculiasis was considered to be suitable for eradication for a number of reasons. It is very easily diagnosed (the emergence of a long worm from one’s foot is quite distinctive) which is important for surveillance (smallpox was also easy to diagnose and surveil for, unlike malaria). (1,5) It is seasonally transmitted which gives time to plan and reflect on the past year’s efforts and predict where the next year’s outbreaks are likely to be. (1,6) It was also distributed in relatively localized pockets in its endemic range, as opposed to being widespread. (7) It also does not spread in an airborne manner like malaria, which spreads via mosquito bite. (5) This means that guinea worm-containing water sources are the only way to get infected, which provides a useful point to control. (7) At the time, it had no known animal reservoirs. Since then, it has been discovered that dogs can also be infected with dracunculiasis which has complicated the matter of eradicating the last cases. (4) Interestingly, between 1923 and 1932 dracunculiasis was successfully eradicated from a few settlements in the USSR. This was much earlier than the worldwide guinea worm eradication program. The fact that only 8 settlements were affected and the presence of a safe water supply made the task much easier. (8) No references were made to the USSR’s eradication program in materials about the global guinea worm eradication program. India was the first country to start its program, starting surveillance against dracunculiasis in 1980. In 1996 India reported its last case, several years after Pakistan, which reported its last case in 1993. (1)

Pakistan’s guinea worm eradication campaign began in 1987, funded largely by the Carter Center’s Global 2000 project, with additional funding by the government of Pakistan, the CDC, the WHO and UNICEF. The CDC also provided technical assistance. The program started by conducting surveillance to find villages that were endemic for dracunculiasis. Out of approximately 50,000 villages in Pakistan, 47,401 villages were searched and 401 villages were found to be endemic for dracunculiasis. The search was conducted by health workers that had previously worked in other programs in the country, such as anti-malaria efforts. Schoolteachers also helped with the efforts. (9)

By September 1987, interventions against dracunculiasis began. There were 3 provincial managers who were in charge of selecting and training village health workers (also referred to as village implementors), who would work part time, one in each endemic village, to report dracunculiasis cases and provide health education for villagers. There were also health workers who were trained to apply larvicide. (9) Independent evaluation of the program in December 1988 found that some of the village health workers were not performing adequately, so a new role, the Sector Supervisors, was created. In February 1989, an additional search of villages in 2 districts that had previously not been searched was done and 80 more endemic villages were found. Additionally, 3 other districts were searched and no endemic villages were found. By the end of 1989, 530 villages were being monitored, an increase from the 401 villages that were originally found. (10) This shows the ability of the eradication program to assess whether it was currently successful and adapt to local circumstances, since the need for more supervision of village health workers was not anticipated, and an additional broad search for endemic villages was not originally planned. As will be discussed later, the malaria eradication program did not do this well. In November 1989, the program switched to case containment, a strategy that was also used in the Smallpox Eradication Program. It involved more intense monitoring of individual cases. (9) Cash rewards were also implemented for reporting the first case in a village, and also for the patient and the person who reported the case. This was a novel strategy used in guinea worm eradication. (11) Additionally, the number of villages being monitored was reduced to about 150 total, ending monitoring of villages that had not had a case in the past 3 years. (9) These changes also show the ability of the program to be flexible and change its strategy to what works best given the circumstances. A 3-year period where no transmission took place was necessary for the WHO to certify that a country was dracunculiasis-free. Pakistan reported its last cases in 1993 and was certified free of dracunculiasis in 1997. (11, 12)

Several techniques were used in the eradication of dracunculiasis: surveillance, creation of safe water sources, use of larvicides to kill copepods, and health education. According to a report from the WHO, “Several methods pioneered (as far as dracunculiasis eradication is concerned) by the Pakistan GWEP, such as the use of village-based health workers, annual programme reviews, and case containment, have been incorporated into all other Guinea-Worm Eradication Programmes in Africa, where they have proven effective when used against much higher numbers of cases.” (11) Surveillance included both the initial surveillance done to determine which villages were endemic and also ongoing surveillance. It also included case containment, a more intensive form of surveillance that focused on finding individual cases. It was based on techniques used in the smallpox eradication program, so it was not a new strategy, but it was newly used in the guinea worm eradication program. A case is considered contained if it is detected within 24 hours of worm emergence, the patient does not contaminate a water source, the patient receives care (wound cleaning/bandaging) and health education. (1) Patients were also asked about their travel history to find other water sources they had potentially contaminated. It was considered to be most effective in countries with relatively low numbers of cases, hence why it was not a strategy used at the beginning of the program. Approximately 86% of cases ended up being contained within 24 hours, according to a report from 1991 when case containment was underway. (13)

The creation of safe water sources such as drilled wells was not of much use in Pakistan due to brackish underground water in endemic regions. (11) A larvicide known as temephos or ABATE was used widely in Pakistan’s guinea worm eradication program to kill the copepods, being applied in monthly intervals by health workers during the transmission season. (10) Much of it was donated to the various national guinea worm eradication programs by its manufacturer. Applying larvicide was labor-intensive, had to be repeated monthly, and there were sometimes issues with finding all of the contaminated water sources and applying a sufficient amount of larvicide. Health education ended up being one of the most important strategies, sidestepping the issues with providing safe water sources. (14) The malaria eradication program also relied on chemical control of mosquitoes and had similar issues, but it was their only strategy. (5) The guinea worm campaign  was fortunate to have another strategy. Health education was done by the village implementors who visited villages monthly. (13) It involved teaching villagers to report dracunculiasis cases, to use cloth filters that were provided by the village implementors, and to not contaminate water sources by submerging their limbs in them. (1) Many villagers did not know how dracunculiasis was transmitted so education was a simple and effective way to break transmission and empower villagers to help themselves. (14) Pakistan’s eradication program was evaluated at the end of each year to ascertain its success and discuss changes that needed to be made. The evaluations helped the program determine what direction to take next and whether there were issues with the current strategies, such as when it was determined that the village implementors needed more supervision, or the switch to case containment. (9) The techniques pioneered in Pakistan’s program (use of village health workers, annual evaluations, and case containment) ended up being used in the eradication programs in other countries which shows how encouraging flexibility can come up with novel effective techniques that may be widely useful. (11)

Primary healthcare was a healthcare paradigm first introduced in the late 1970s that focused on community participation and mobilization in healthcare, addressing basic needs, and focus on poor and rural populations. The guinea worm eradication program did have a focus on community mobilization, because whether filters were used effectively and people avoided contaminating water depended on the actions of villagers, although villagers were not consulted to help with planning. Primary healthcare also focused on improving general living conditions. With guinea worm, there was a focus on improving water quality and providing safe water sources which also leads to a general quality of life improvement. (3) However, in Pakistan not many new water sources (e.g. wells) were created due to the salinity of local groundwater. (11) While providing clean water sources for everyone turned out to be impractical, educating people on use of filters was cheaper but effective. (15)

Before the guinea worm eradication campaign, there were two other major worldwide disease eradication campaigns, both headed by the WHO. The malaria eradication campaign started in 1955 and was terminated in 1969, having been considered a failure, despite a reduction in malaria incidence and some countries achieving eradication. Malaria is spread by mosquitoes and pesticides sprayed on walls of houses were used to interrupt its transmission. Local successes with the use of pesticides had shown that eradicating the disease on a wider scale may have been possible. The smallpox eradication campaign started in 1959 and succeeded at its goal of eradicating smallpox through the use of vaccines. (5) The success of the smallpox eradication campaign inspired the guinea worm eradication campaign, as dracunculiasis had some features in common with smallpox. (7) Mass vaccination against smallpox turned out to be unfeasible so the smallpox eradication campaign ended up switching focus to case containment, which involved surveillance to find individual cases and then “ring vaccination” of those around the sick individual. (5) The guinea worm eradication program used the same principle with their case containment, “Find the patient and then break the transmission chain through quick, local and focused action”, either ring vaccination or education for the dracunculiasis patient about how to avoid contaminating water. (6,1)

Part of why the smallpox eradication program was considered more successful than its earlier counterpart was that it was more flexible and adapted better to new research as it came out. The people in charge of it had learned from the inflexibility of the malaria eradication program and allowed more freedom on the local level and encouraged research to be done. In the malaria eradication campaign, there had been issues regarding the effectiveness of the pesticides used to spray house walls as some types of wall material would absorb them and render them ineffective. There were also issues with lack of training of program staff and a lack of surveillance, especially as the number of malaria cases started to drop which made new surveillance strategies necessary. (5) These issues were brought up by the Expert Committee in a meeting in 1961, but were largely ignored, the report only calling for minor changes in strategy. As Packard states, “It insisted that if there were problems with the program methods, it was in their implementation, not their conception”. (16) The smallpox eradication program learned from the issues with inflexibility that the malaria eradication program had. Research was encouraged in the smallpox eradication program and findings from research were important to its success. Packard states “Of particular importance were the early findings… that smallpox spread less rapidly and less easily than was thought, and that the prompt detection and immediate containment of outbreaks was the most cost-effective means of pursuing the goal of eradication.” (43) Ring vaccination, one of the most important strategies of the smallpox eradication program, was not initially planned on and was first used in the campaign in Nigeria despite resistance from the local government. It ended up being very effective and other countries ended up using it in their eradication programs. (5) The guinea worm eradication program in Pakistan was similarly flexible, having yearly meetings to discuss strategies and assess whether the program had been successful so far. (9) The guinea worm campaign was directed by Donald R. Hopkins, who directed Sierra Leone’s smallpox eradication campaign, which shows there was some overlap in leadership between the two campaigns. (5)

It should also be said that the different levels of success of the different campaigns was not only due to social factors, but due to the features of the available eradication strategies. Malaria is harder to survey for due to its wider variety of symptoms (including asymptomatic cases), unlike smallpox which causes a distinctive rash or dracunculiasis which involves the emergence of a distinctive worm. Spraying pesticides was also not as simple and effective as vaccination and had to be done multiple times, unlike vaccination which was one-and-done. (5) In the case of dracunculiasis eradication, larvicide also had to be reapplied regularly, but cloth filters and health education were another strategy used that was longer-lasting. Cloth filters seemed to generally need replacement after a year but cloth (sometimes cotton, usually monofilament nylon or polyester) was cheap and easy to use and the benefits of health education could be long-lasting, as people remember what they are taught. In parts of Sudan where there was a shortage of cloth for filters, an 88% case reduction was managed over the course of a year, despite only 44% of households having a filter. People were able to reduce incidence by changing their behavior. (14)

As of the year 2024, only 14 human cases of dracunculiasis were reported. 664 animal cases were reported, which were almost entirely dog cases. Surveillance for cases continues to be done by volunteers in villages that are endemic for dracunculiasis or at high risk for dracunculiasis being imported. As of 2026, only 6 countries are currently reporting transmission of dracunculiasis. (Angola, Cameroon, Chad, Ethiopia, Mali, and South Sudan) The civil unrest in South Sudan has made surveillance and eradication activity difficult. (4) Additionally, the discovery of dogs as a reservoir for dracunculiasis has complicated matters. Cases of dracunculiasis in dogs were first discovered in Chad in 2012. As of 2017, the only countries with reported human dracunculiasis cases were Chad and Ethiopia but as of 2025 more countries have reported transmission. (2) It is unclear whether these instances of renewed transmission are due to a country being truly free of dracunculiasis and it being imported, or due to a lack of surveillance. (surveillance being especially difficult because dracunculiasis mostly affects poor, rural, possibly war-torn areas.) This shows the importance of surveillance in disease eradication, because it is impossible to determine whether efforts have been successful and what still needs to be done if there isn’t information on what’s really going on.

The eradication campaign against dracunculiasis has been largely successful, reducing annual human cases from the millions to only a few dozen. Pakistan was the first country to completely eradicate dracunculiasis, having created innovative techniques to find and prevent cases of the disease. It also built off lessons learned from the recent successful smallpox eradication campaign with its adaptability. The recent discovery of an animal reservoir for dracunculiasis has complicated the matter of eradicating the last few cases, but the progress made in dealing with this debilitatingly painful disease has been incredible.