[Follow-up survey on the long-term effects of DEC medicated salt in the control of filariasis bancrofti (author's transl)]. Eradication of bancroftian filariasis by diethylcarbamazine-medicated common salt on Little Kinmen (Liehyu district), Kinmen (Quemoy) Islands, Republic of China. Field trial on control of bancroftian filariasis using common salt medicated with diethylcarbamazine. Filariasis eradication on Kinmen Proper, Kinmen (Quemoy) Islands, Republic of China. Mass treatment of filariasis using DEC-medicated salt. Efficacy of diethylcarbamazine medicated salt in interrupting Brugia malayi transmission in hill tribe settlements in Kerala State. A community-based trial for the control of lymphatic filariasis and iodine deficiency using salt fortified with diethylcarbamazine and iodine. Efficacy of mass single-dose diethylcarbamazine and DEC-fortified salt against bancroftian filariasis in Papua New Guinea six months after treatment. Long term effect of diethylcarbamazine medicated common salt on bancroftian filariasis. Control of Bancroftian filariasis by cooking salt medicated with diethylcarbamazine. The effect of salt medicated with diethylcarbamazine in bancroftian filariasis. Control of bancroftian filariasis by salt medicated with diethylcarbamazine citrate. The efficacy, tolerability and safety of diethylcarbamazine-fortified salt in the treatment of the microfilaraemias of brugian filariasis: an open, hospital-based study. Long-term effect of mass diethylcarbamazine chemotherapy on bancroftian filariasis, results at four years after start of treatment. Efficacy of diethylcarbamazine-medicated salt for microfilaraemia of Brugia malayi.
nan Since bancroftian filariasis constituted a major public health problem on Little Kinmen (Liehyu District), Kinmen (Quemoy) Islands, a control programme was conducted on this island from 1970 to 1982. A pre-control survey recorded a microfilarial rate (mfr) of 9.6%, a night blood microfilarial density (mfd) of 14.4/20 microliters blood, and a clinical rate of 26.2%. Culex quinquefasciatus was found to be the only vector of the parasitosis on the island, with an infection rate (Ir) with all filarial larval stages of 9.1% and a larval density (Ld) of 6.2. Diethylcarbamazine (DEC)-medicated salt (0.33% w/w) was administered to the whole population on Little Kinmen. Each person was estimated to take 12.7 g salt with 42 mg DEC daily for six months (July-December 1974). All accepted the programme, and no adverse side-effect was noted. During the control, the mfr and mfd were reduced to 0.3% and 1.9/20 microliters blood. The Ir and Ld were reduced to 0.8% and 1.3. Eight post-control surveys (1975-1982) revealed only two of 459 pre-control carriers positive and the remaining population of 7125 inhabitants negative. The two carriers were cured with a course of 5 g DEC. All family members of these carriers and their neighbours' families were given DEC-medicated salt for four months to clear the only remaining source of filarial transmission. In addition to a reduction in the prevalence of filariasis in humans and in mosquitoes to zero, the clinical manifestations disappeared in 52.4% of the pre-control carriers and improved in 19.0%. There was no change in 19.8 and 8.7% had new manifestations. nan A control program for bancroftian filariasis was conducted on Kinmen Proper from 1970 to 1982. The combined method of mass chemotherapy with diethylcarbamazine (DEC) for microfilarial carriers and larvicide with sumithion for mosquitoes was used on the island for 3 years (1974-76). The microfilarial rate and microfilarial density decreased from 8.4% and 14.6/20 microns in 1970-73 to 0.7% and 5.3/20 microns in 1976. The infection rate, infective rate, and larval density of Culex quinquefasciatus, the only mosquito vector of the parasite, decreased from 10.3%, 6.4%, and 6.4 in 1970-73 to 0.3%, 0.2%, and 1.3, in 1976, respectively. For final elimination of the infection, DEC medicated salt (0.33%, w/w) was then administered to the whole population for 6 months (March-September 1977). All accepted the program and no adverse side-effects were noted. Six annual follow-up surveys (1977-82) revealed only 3 out of 3853 previous carriers to be positive. These carriers were cured with a course of 5 g DEC. All family members of the 3 carriers and of the 12 neighbouring families were also given DEC medicated salt for 4 months in order to clear the only remaining source of filarial transmission. In conclusion, administration of DEC medicated salt is simple, rapid, safe, inexpensive, efficient, and practical for filariasis control or eradication. Diethylcarbamazine (DEC)-medicated salt was used to control bancroftian filariasis in 20 endemic counties and cities of Fujian Province in China. The population was 5,189,126 and the microfilaria (mf) rates were between 1.56 and 11.81%. The total dose of DEC was 6-10.5 g per person over a period of 2-4 months. Six to 9 months after treatment the mf rate was reduced to 0-0.57% with a mean of 0.07% (621/823,796). In 184 villages sampled one year post treatment the mf rate was 0.22% (371/171,067) and in 29 villages 2-4 years after treatment the mf rate was 0.05% (31/56,459). In a region of endemic Malayan filariasis, with a population of 67,778 and mf rate of 3.82-4.36%, treatment with DEC-medicated salt to a dosage of 3.2 g DEC per person was administered for 2 months. Six months after treatment the mean mf rate was reduced from 4.08 to 0.26% (10/3841). Filariasis in all the villages controlled with DEC-medicated salt reached the basic criteria of elimination (mf rate below 1%). A filariasis survey carried out about eight years after achieving zero microfilaria (mf) rates following administration of diethylcarbamazine (DEC) medicated salt in the Kani hill tribe settlements in Quilon and Thiruvananthapuram districts of Kerala State revealed that there was no reappearance of Brugia malayi infection in the experimental areas. Mf rates were maintained at zero level in the experimental villages, while in the control villages, 2.9 per cent mf positives were observed. Mansonia (Mansonioides) uniformis dissected did not reveal filarial infection. It is concluded that DEC medicated salt regime in the experimental areas of Kani hill tribe settlements has been successful in effectively interrupting B. malayi transmission. Pilot studies in other B. malayi endemic areas of India using DEC medicated salt regime with the objective of eliminating B. malayi transmission are advocated, since the parasite has a restricted distribution in India and is already showing a declining trend. To evaluate the effectiveness of salt fortified with diethylcarbamazine (DEC) and iodine for elimination of Bancroftian filariasis and iodine deficiency, all consenting residents of Miton, Haiti (n = 1,932) were given salt fortified with 0.25% diethylcarbamazine and 25 ppm of iodine for one year. Wuchereria bancrofti microfilaria prevalence and intensity, antigenemia, and urinary iodine were measured before and one year after salt distribution began. To measure the effect of DEC-fortified salt on adult worm motility, 15 microfilaria-positive men were examined by ultrasound of the scrotal area. Entomologic surveys were conducted to determine the proportion of W. bancrofti-infected Culex quinquefasciatus. After one year of treatment, the prevalence and intensity of microfilaremia were both reduced by more than 95%, while antigenemia levels were reduced by 60%. The motility of adult worms, as detected by ultrasound, was decreased, but not significantly, by DEC-fortified salt. The proportion of vector mosquitoes carrying infective stage larvae decreased significantly from 2.3% in the nine months before the intervention to 0.2% in the last three-month follow-up period. Iodine deficiency, which had been moderate to severe, was eliminated after one year of iodized salt consumption. The DEC-fortified salt was well accepted by the community and reduced microfilaremia and transmission to low levels in the absence of reported side effects. Based on these results, salt cofortified with DEC and iodine should be considered as a concurrent intervention for lymphatic filariasis and iodine deficiency elimination programs. The efficacy of two diethylcarbamazine (DEC) treatment strategies to control bancroftian filariasis, diethylcarbamazine-fortified salt (DEC-FS) and a single DEC dose on mass administration, was evaluated in two communities in Papua New Guinea with pretreatment antigen prevalence of 55% and 71%. In the first community 0.2% w/w diethylcarbamazine-fortified salt was distributed monthly to accepting households at no cost for 12 months. In the second community a single DEC dose based on body size but designed to give about 6 mg/kg was administered to eligible acceptors. Despite wide variation in antigen prevalence among study villages there were marked reductions in prevalences under both treatment strategies. Among individuals antigenaemic on day 0, DEC-FS and a single DEC dose gave filaria antigen clearance rates of 43% and 13%, respectively. In the salt-treated community the incidence of antigenaemia after 6 months in acceptors from households that received 5 kg or more of DEC-FS was 14% whereas in those receiving less than 5 kg salt was 4%. The incidence rates in the second community in those that received < 2.5 and > or = 2.5 tablets were 16% and 8%, respectively. The two treatment strategies were simple to manage and appropriate for developing countries and were widely accepted. DEC-FS was more efficacious than single-dose DEC tablets but a single administration of DEC tablets is easier to administer. nan In small-scale pilot trials, filarial infection can usually be reduced to low levels by oral administration of diethylcarbamazine to all the persons concerned; but in mass campaigns it is often difficult to persuade large numbers of people to swallow the tablets. In order to overcome this difficulty the authors propose that the compound be incorporated into cooking salt, as has been done with chloroquine to control malaria. There are many reasons why this method of medication should be more effective against filariasis than it has often been against malaria.Laboratory trials showed that cooking the compound in food did not make it toxic for rats or diminish its antifilarial activity. A pilot trial was carried out at Recife, Brazil, in which 1000 adults received salt containing 0.4% diethylcarbamazine (corresponding to a daily intake of 100 mg/day) for 40 days, and then salt containing 0.1% compound for a year. This medication was simple to administer; it was quite acceptable to the subjects; it caused no untoward effects; and it removed almost all the microfilariae from the blood. Administration of medicated salt (0.3%) for 18 days to another group of 1300 adults was well tolerated and produced a considerable reduction of the microfilarial load; but this short period was insufficient to remove all the microfilariae.The authors recommend that this method of administering diethylcarbamazine to large numbers of people should be investigated further to see if it could be used for mass campaigns to control filariasis. The paper describes a trial conducted in Tanzania of the effect on bancroftian microfilaraemia of common salt medicated with diethylcarbamazine at a 0.1% (w/w) concentration, when given to a closed population of 600-700 with a known salt intake.After good observer agreement in microfilarial counting had been demonstrated, quantitative blood surveys were performed monthly on known carriers. Paired pretreatment microfilarial counts from the same patients at an interval of 4 months suggested a natural fluctuation in microfilarial densities and emphasized the need for parallel concurrent controls during treatment.During the trial the mean microfilarial densities fell steadily, being reduced by 73% at 3 months and 90% after 6 months. Tolerance to the drug-salt mixture was extremely good.Problems of planning, salt preparation and assessment of results are discussed and the importance of correct experimental design in future trials is stressed. The authors suggest that a trial of salt containing 0.2% (w/w) diethylcarbamazine may achieve optimum results. They point out that, while the use of diethylcarbamazine-medicated salt may prove useful in reducing transmission in closed communities or in endemic areas with no alternative source of salt, its extension to national populations as a sole means of bancroftian filariasis control would be of problematical value. nan Cooking salt fortified with diethylcarbamazine (DEC) has been successfully used to control lymphatic filariasis in several parts of the world. The kinetics and efficacy of DEC-fortified salt in clearing microfilaraemias of Brugia malayi and the salt's tolerability and safety are examined in this study. Twenty individuals with B. malayi microfilaraemias (pre-treatment levels of 108-6358 microfilariae/ml; median = 309/ml) consumed DEC-fortified salt (0.2%, w/w) with their food for 1 year, initially in hospital (for 1 week) and later at home. The mean daily intake of DEC was 21.4 mg (range = 9.0-39.4 mg). Even on the first day of consuming the salt, there was a decrease in the microfilarial levels of 14 patients and a sharp increase in six patients. Microfilarial levels tended to fluctuate thereafter but there was a progressive, general decline. At the end of the study year, eight patients were amicrofilaraemic and microfilarial clearance was > 95% in 58% of the patients. Eight patients did not develop any adverse reactions. Lymph-node tenderness and enlargement were seen in eight patients (40%), and dilated, inflamed lymphatic channels standing out as cords ('string sign') were seen in another five patients. These reactions were transient and did not require any specific treatment. The DEC-fortified salt was well accepted by the study population. The DEC content of fortified salt and the duration of its use for the control of brugian filariasis need to be re-examined. Health education should include messages that mild, self-limiting, adverse reactions are likely to occur even with the use of such salt. The long-term effect of 4 strategies for control of bancroftian filariasis using mass diethylcarbamazine (DEC) chemotherapy was assessed and compared in 4 endemic communities in Tanzania over a period of 4 years. The strategies were the standard 12 d treatment (strategy I), semi-annual single dose treatment (strategy II), monthly low dose treatment (strategy III), and DEC-medicated salt treatment (strategy IV). Treatment was given only during the first year. All strategies resulted in considerable reductions in microfilaraemia, with maximum effects occurring 1-2 years after start of treatment. At 2 years, the greatest reductions were seen for strategies III and IV, followed by strategy II and finally strategy I. The overall performance of the 4 strategies evaluated over the 4 years period followed the same sequence. Between the 2 years and 4 years follow-up surveys, a significant increase in microfilarial (mf) burden occurred in all 4 communities, but the mf geometric mean intensities (GMI) remained low. Thus, in individuals who were microfilaraemic before treatment, the rates of microfilaraemia were 66%, 44%, 34% and 43%, and the mf GMIs were 6.8%, 3.3%, 0.5% and 0.7%, of pre-treatment level, 4 years after start of treatment with strategies I, II, III and IV, respectively. Most individuals who developed microfilaraemia between the 2 years and 4 years follow-up surveys had been microfilaraemic before the start of treatment. Hence, the rate of development of microfilaraemia was much higher (18 times on average in the 4 communities) among those who were microfilaraemic before treatment than among those who were amicrofilaraemic. The long-lasting effect of treatment adds a promising potential to the use of mass DEC chemotherapy for the control of bancroftian filariasis. Pilot studies in India and abroad have demonstrated the benefit of cooking salt fortified with diethylcarbamazine citrate (DEC) for the control of lymphatic filariasis. In India, DEC-medicated salt has been introduced on a commercial basis in the Cherthala region of Kerala, which is endemic for Brugia malayi (B. malayi). We studied the efficacy of DEC-medicated salt in the clearance of microfilaraemia of B. malayi.
                Eighteen cases of microfilaraemia (11 men; 7 women) were selected; 14 in the experimental group (i.e. treated with 0.2% w/w DEC-medicated salt) and the rest as the control group who were given a placebo. The consumption of salt and the status of parasitaemia were monitored till all the microfilaria carriers became negative.
                There was a significant reduction in the density of microfilariae (intensity) among the treated individuals over a period of time. The duration required for the clearance of microfilariae ranged from 9 to 30 [mean (SD) 19.4 (1.7)] weeks. All microfilaraemics except one reported side-effects which were mild-to-moderate and persisted for a maximum period of one month.
                DEC-medicated salt effectively clears microfilariae within 30 weeks in parasitaemic individuals. No 'endemic normals' reported any side-effects, though these were common among the microfilaria carriers.
DEC-medicated salt is an effective intervention when maintained with levels of coverage of at least 90% for at least six months. Further studies are required to assess the effects of continuous low-dose, DEC-medicated salt on adult worms, disease prevalence, and development of drug resistance.