Differentiating Dracunculus medinensis from D. insignis, by the sequence analysis of the 18S rRNA gene.

This study, undertaken as a component of the global Dracunculiasis Eradication Program (DEP), was designed to provide molecular tools to distinguish Dracunculus medinensis, the nematode causing human dracunculiasis, from other tissue-dwelling nematodes, including other Dracunculus species that infect humans and other animals. DNA was extracted from D. medinensis and from a closely related species that infects North American carnivores, D. insignis, so that the genes coding for the small-subunit ribosomal RNA (18S rRNA) of the parasites could be amplified, sequenced and compared. Sequences were obtained for 20 specimens of D. medinensis (from humans in Pakistan, Yemen and six African countries endemic for dracunculiasis) and three of D. insignis (from raccoons trapped in the state of Georgia in the southern U.S.A.). All of the D. medinensis 18S-rRNA sequences were found to be 1819 bases long and identical. The three D. insignis 18S-rRNA sequences were also found to be identical to each other but were 1821 bases long and differed from the D. medinensis 18S- rRNA sequence at eight positions (representing a difference of 0.44%). The 18S-rRNA coding region of a Guinea worm extracted from a dog in Ghana was indistinguishable from that of the D. medinensis isolates from human cases. These results provide the basis for the molecular differentiation of D. medinensis that will permit the DEP to determine, rapidly and accurately, whether a worm recovered from an area considered dracunculiasis-free is a specimen of D. medinensis or not.

Dracunculus medinensis and Schistosoma mansoni contain opiate alkaloids.

The results of analysis, by high-performance liquid chromatography coupled with electrochemical detection and by nano-electrospray-ionization, double quadrupole/orthogonal-acceleration, time-of-flight mass spectrometry, indicate that adult Dracunculus medinensis and Schistosoma mansoni both contain the opiate alkaloid morphine and that D. medinesis also contains the active metabolite of morphine, morphine 6-glucuronide. From these and previous observations, it would appear that many helminths are probably using opiate alkaloids as potent immunosuppressive and antinociceptive signal molecules, to down-regulate immunosurveillance responsiveness and pain signalling in their hosts.

Misidentification of Onchocerca volvulus as guinea worm.

Over the past 10 years, the status of human infection with guinea worm (Dracunculus medinensis) in the Central African Republic (CAR) has been difficult to ascertain. It is unclear if indigenous cases are occurring and whether cases are migrating into the CAR from surrounding countries. A team of investigators visited the CAR in July-August 2000, to attempt to ascertain the presence of indigenous transmission. No cases of true guinea-worm infection (i.e. dracunculiasis) were detected, but three cases of human infection with Onchocerca volvulus, each of which had been misidentified as dracunculiasis, were detected. The unusual presentation of skin blisters and extraction of an intact female O. volvulus are described. As a result of this investigation, and the confusion of onchocerciasis being misidentified as dracunculiasis, the presence of endemic transmission of guinea worm in the CAR remains in question.

Dracunculiasis eradication: delayed, not denied.

By the end of 1998, Asia was free of dracunculiasis (Guinea worm disease), with Pakistan, India, and Yemen having interrupted transmission in 1993, 1996, and 1997, respectively. Transmission of the disease was also interrupted in Cameroon and Senegal during 1997. Chad reported only 3 cases during 1998. Dracunculiasis is now confined to only 13 countries in Africa. The overall number of cases has been reduced by more than 97% from the 3.2 million cases estimated to have occurred in 1986 to 78,557 cases reported in 1998. Because the civil war in Sudan remains the major impediment to eradication of dracunculiasis, the interim goal is to stop all transmission outside that country by the end of 2000. The most important operational need now is for national programs to improve the frequency and quality of supervision of village-based health workers in order to enhance the sensitivity of surveillance and effectiveness of case containment.

Dracunculiasis eradication: almost a reality.

The idea of a global campaign to eradicate dracunculiasis was first proposed by the Centers for Disease Control and Prevention in 1980, during the advent of the International Drinking Water Supply and Sanitation Decade (IDWSSD) (1981-1990). In 1981, the Steering Committee of the IDWSSD adopted eradication of dracunculiasis as a subgoal of their efforts to provide safe drinking water to unserved populations. In 1988, African ministers of health voted to eradicate dracunculiasis by the end of 1995, a target date that was endorsed by UNICEF in 1989 and the World Health Assembly in 1991. Although nine of 18 endemic countries, India (1980), Pakistan (1987), Nigeria and Cameroon (1988), Ghana (1989), and Mauritania, Benin, Burkina Faso, and Togo (1990) completed national searches for cases of the disease, only four countries, India (1983), Pakistan (1988), Ghana (1989), and Nigeria (1989), actually started eradication programs during the 1980s. The remaining 14 endemic countries began their eradication programs between 1991 and 1995. At the end of 1996, dracunculiasis had not been entirely eradicated, but its incidence had been reduced by 95%, from an estimated 3.2 million cases in 1986 to 152,805 cases in 1996. Sudan reported a total of 118,578 (78%) of the 152,805 cases of dracunculiasis reported during 1996. Insufficient funding and the civil war in Sudan continue to be the major obstacles to overcome. A primary aim of the eradication program in 1997 is to seek to ensure that all cases of dracunculiasis outside of Sudan are contained. In Sudan the challenge is to pursue all appropriate control measures in all accessible areas as vigorously as possible until political circumstances allow access to all of the remaining affected areas.

The efficacy of oxamniquine in acute schistosomiasis: a clinical analysis of 28 treated patients

During the summer of 1980, acute Manson's Schistosomiasis occurred in 28 pediatric patients, swimming in two ponds with no watershed connections between them, in the rural area of Juncos and Cidra, Puerto Rico. Clinical and immunological events were studied and Oxamniquine (Vansil, Pfizer) was administered to all of them and followed closely for 3 years. Fever and general malaise recorded in 93 of the patients, diarrhea and abdominal pain in 68 and urticaria or facial edema in 64. Hepato and/or splenomegaly was recorded in 71 of them. Twenty seven of the patients had evidence of immunoserological activity against adult schistosomal antigens (GASP and PSAP). Two patients had intense immunologic activity, even before the recovering of fresh Schistosoma mansoni eggs in their stool. This was a response to GASP and PSAP antigens. When they started passing fresh eggs of schistosoma and COP (Circumoval Precipitation Test) turned positive, their clinical status worsened and antibodies to GASP antigen increased two fold. The oviposition phase elicited a strong antibody and immunological reaction with significant eosinophilia and cross reaction was observed between adult schistosomal and egg shell antigens. Severe clinical manifestations were seen in spite of low egg excretion. Oxamniquine was effective in obtaining a coprological cure and in altering the immunologic response as compared with other untreated groups in literature

The efficacy of oxamniquine in acute schistosomiasis: a clinical analysis of 28 treated patients.

During the summer of 1980, acute Manson's Schistosomiasis occurred in 28 pediatric patients, swimming in two ponds with no watershed connections between them, in the rural area of Juncos and Cidra, Puerto Rico. Clinical and immunological events were studied and Oxamniquine (Vansil, Pfizer) was administered to all of them and followed closely for 3 years. Fever and general malaise recorded in 93% of the patients, diarrhea and abdominal pain in 68% and urticaria or facial edema in 64%. Hepato and/or splenomegaly was recorded in 71% of them. Twenty seven of the patients had evidence of immunoserological activity against adult schistosomal antigens (GASP and PSAP). Two patients had intense immunologic activity, even before the recovering of fresh Schistosoma mansoni eggs in their stool. This was a response to GASP and PSAP antigens. When they started passing fresh eggs of schistosoma and COP (Circumoval Precipitation Test) turned positive, their clinical status worsened and antibodies to GASP antigen increased two fold. The oviposition phase elicited a strong antibody and immunological reaction with significant eosinophilia and cross reaction was observed between adult schistosomal and egg shell antigens. Severe clinical manifestations were seen in spite of low egg excretion. Oxamniquine was effective in obtaining a coprological cure and in altering the immunologic response as compared with other untreated groups in literature.

Eradication of dracunculiasis from Pakistan.

In 1986 the World Health Organization targeted dracunculiasis (Guinea-worm disease), which seriously impairs socioeconomic development in 16 African countries, India, Pakistan, and Yemen, to be eradicated globally. The target date for eradication by the end of 1995 was established in 1991. Pakistan eradicated dracunculiasis from the country in October, 1993, after a national campaign which began in 1987 with a nationwide village-by-village search for cases. The infection, which is transmitted by drinking water from ponds containing infected water fleas, was eradicated by using health education, cloth filters, and the cyclopsicide, temephos; and in the later stages, by case containment. Methods pioneered in Pakistan's National Guinea Worm Eradication Program are now being applied in remaining endemic countries.

PIP: Dracunculus medinensis larvae expelled into drinking water may be ingested by water fleas, copepods, in which they undergo two moults before becoming infectious to humans. A person consuming unboiled or unfiltered water infested with larvae-ridden copepods will contract dracunculiasis. The disease is manifest one year later by the emergence from the human host of one-meter-long adult worms of Dracunculus medinensis. Infected people are often incapacitated for several weeks by secondary infections associated with the emergence of the worm, although less than 1% of victims suffer permanent disability. The disease is rarely fatal, but it prevents large numbers of people from farming or attending school. Dracunculiasis, Guinea-worm disease, can be prevented by boiling drinking water or filtering it through a cloth to remove the larvae's copepod hosts, by educating villagers not to contaminate their sources, by providing clean drinking water from underground sources such as borehole wells which cannot be contaminated, or by using a larvicide, temephos, to kill the copepods while leaving the water safe for human consumption. In 1986, the World Health Organization targeted dracunculiasis for global eradication. From an estimated total of more than three million cases in 1986, only 165,000 cases were reported worldwide in 1994. Pakistan, however, is the first country endemic for dracunculiasis to eradicate the disease during the ongoing global campaign. The goal of countrywide eradication was reached in October 1993 after a national campaign which began in 1987 with a nationwide village-by-village search for cases. Health education, cloth filters, temephos, and case containment were used together to achieve success. Methods pioneered in Pakistan's guinea-worm eradication program are being applied in the remaining endemic countries.

Dracunculiasis eradication: March 1994 update.

Substantial progress has been realized in the global campaign to eradicate dracunculiasis by the end of 1995 since a previous review of the subject was published in this journal a year ago. All known endemic countries are now engaged in the eradication effort, and one or more control measures are now in place in 93% of endemic villages. Despite improved surveillance for the disease, the number of reported cases of the disease has been reduced by 41% (to about 221,000), and the number of known endemic villages has been reduced by 28% (to about 16,500) in the past year. Priorities for national eradication programs in 1994 include increasing the use of vector control and intensifying the case containment strategy in endemic villages. It is still possible to achieve the eradication target of December 1995, but greatly intensified efforts this year will be required to do so.

Dracunculiasis eradication: beginning of the end.

Beginning with the International Drinking Water Supply and Sanitation Decade (1981-1990), an increasingly broad coalition of international and bilateral agencies, organizations, private companies, and other institutions have joined forces to eradicate dracunculiasis (Guinea worm disease). From an estimated annual incidence of 10 million persons just before the campaign began, the remaining incidence of cases is now less than two million. More than 23,000 villages are known to be endemic. All 18 countries where the disease is still endemic have completed or begun nationwide searches to identify endemic villages, except Kenya. Dracunculiasis is nearly eradicated in Asia, where Pakistan found only 23 cases in 1992, and India found 1,081 cases. Cameroon and Senegal are close to achieving eradication in Africa, where the two formerly highest endemic countries, Nigeria and Ghana, reduced their combined total of cases from approximately 820,000 in 1989 to less than 240,000 in 1992. Much remains to be done, however, in francophone West Africa and especially in East Africa. The most serious current obstacles to eradicating dracunculiasis by 1995 are the civil war in Sudan, apathy of some national and international health officials, and inadequate funding for the campaign.

Surveillance for dracunculiasis, 1981-1991.

In 1986 the World Health Organization (WHO) designated dracunculiasis (guinea worm disease) as the next disease scheduled to be eradicated (by 1995) after smallpox. Dramatic improvement in national and international surveillance has played a key role in the global eradication campaign, which was initiated at CDC in 1980. About 3 million persons are still affected by the disease annually, with adverse effects on their health as well as on agricultural production and education. Over 100 million persons are at risk of having the disease in more than 20,000 villages in India, Pakistan, and 17 African countries. At least one nationwide, village-by-village search to detect all villages with endemic dracunculiasis and count cases is recommended at the outset of each national campaign, followed by monthly reporting by village-based health workers in the targeted villages during the implementation phase. Rapid dissemination of the results of the surveillance is critical. Intensive case detection and containment--with rewards for reporting of cases--are most appropriate near the end of each campaign. Cameroon, Ghana, India, Nigeria, and Pakistan have pioneered the various surveillance methods for this disease in recent years. Methods for conducting surveillance of dracunculiasis and other important diseases must continue to be developed and improved as countries now believed to be free of dracunculiasis prepare to apply to WHO for certification of elimination of dracunculiasis.

Strategies for dracunculiasis eradication.

In 1991 the Forty-fourth World Health Assembly declared the goal of eradicating dracunculiasis (guinea worm disease) by the end of 1995. This article summarizes the recommended strategies for surveillance and interventions in national dracunculiasis eradication programmes. It is based on personal experience with dracunculiasis programmes in Ghana, Nigeria and Pakistan. Three phases are described: establishment of a national programme office and conduct of a baseline survey; implementation of interventions; and case containment. The relevance of dracunculiasis eradication activities to strengthening of primary health care in the three countries is discussed briefly. Similar strategies would help eradicate this disease in the remaining endemic countries.

Strategies for dracunculiasis eradication

In 1991 the Forty-fourth World Health Assembly declared the goal of eradicating dracunculiasis (guinea worm disease) by the end of 1995. This article summarizes the recommended strategies for surveillance and interventions in national dracunculiasis eradication programmes. It is based on personal experience with dracunculiasis programmes in Ghana, Nigeria and Pakistan. Three phases are described: establishment of a national programme office and conduct of a baseline survey; implementation of interventions; and case containment. The relevance of dracunculiasis eradication activities to strengthening of primary health care in the three countries is discussed briefly. Similar strategies would help eradicate this disease in the remaining endemic countries

Dracunculiasis eradication: target 1995.

Substantial progress has been achieved over the past 3 years by the campaign to eradicate dracunculiasis. The target of eradication by 1995 has been set by the African Regional Office of the World Health Organization and accepted by the United Nations Children's Fund (UNICEF) and the United Nations Development Program. India and Pakistan continue to reduce their cases of the disease dramatically. In Africa, Ghana and Nigeria conducted national village-by-village searches in 1988-1990 and, between them, found greater than 800,000 cases of the disease. Most African countries have now prepared national plans of action, appointed national coordinators, and intend to use UNICEF's assistance to conduct national searches by the end of 1990. An international donors' conference held in 1989 facilitated major new assistance for the initiative by UNICEF, the United Nations Development Program, the United States Agency for International Development, the Japanese International Cooperation Agency, the Peace Corps, the American Cyanamid Company, and DuPont. The World Health Organization held a meeting early in 1990 to draft criteria and recommend the process for certifying achievement of elimination of dracunculiasis in formerly endemic countries. The major remaining obstacles to eradication of dracunculiasis by 1995 are civil wars in northeastern Africa and the apathy of some national and international officials.