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PubMed1971

Mosquito-borne infections in Fiji. 3. Filariasis in northern Fiji: epidemiological evidence regarding the mechanisms of pathogenesis.

During a filariasis survey conducted in northern Fiji in 1968-9 examinations were made for microfilaraemia, enlarged lymph nodes and elephantiasis. Analysis of the microfilarial densities at different ages and the number of anatomical sites showing lymph gland enlargement or elephantiasis have been used to provide evidence on the clustering of infections and pathogenesis.Although there is no evidence of clustering of risk of infection, there is evidence favouring the clustering of adult filariae in individuals. Nevertheless the number of sites of lymph node enlargement do not correspond with this finding and statistical evidence suggests that lymph-node enlargement is not necessarily associated with the near presence in the body of adult filariae, whether dead or alive.Males of Indian ethnic origin showed a higher prevalence of elephantiasis than males of Fijian ethnic origin, but women of either ethnic race showed prevalences lower than those of men.The onset of elephantiasis at a site does not directly reflect the number of infections sustained in the local area, but it appears that filariasis first induces for a limited period a proneness to elephantiasis. During this period a random and discrete event may induce the onset of elephantiasis. The nature of the event is unknown, but it probably is not trauma.

Culicidae↗
PubMed1986

Identification of non-cross-reacting antigens of Onchocerca volvulus with lymphatic filariasis serum pools.

Onchocerca volvulus proteins labelled with 125I were immunoprecipitated with onchocerciasis and lymphatic filariasis human serum pools in order to differentiate between cross-reacting and non-cross-reacting antigens. Analysis of the immunoprecipitates by two-dimensional gel electrophoresis revealed that all high molecular weight (Mr) O. volvulus antigens cross-reacted with the lymphatic filariasis serum pools. We observed, however, that at least 8 O. volvulus antigens were specifically immunoprecipitated only by the onchocerciasis serum pools, with Mr ranging from 20,000 up to 43,000 Daltons. These results suggest that the lower Mr O. volvulus antigens are more species specific than the other antigens. The significance of these findings for the immunodiagnosis of onchocerciasis is discussed.

Adult↗
PubMed1989

Bancroftian filariasis in Pondicherry, south India: 1. Pre-control epidemiological observations.

A 5-year Integrated Vector Management (IVM) project was implemented in Pondicherry, South India, for the control of Bancroftian filariasis. The efficacy of the IVM strategy was compared with routine control strategy under the national programme. The present paper describes the pre-control epidemiological features of filariasis as determined by a mass blood survey in 1981. Of 24946 persons examined 8.41% were microfilaraemic. Microfilaraemia prevalence was homogeneous throughout the study area. The prevalence and intensity of microfilaraemia were age dependent, and increased monotonically until about 20 years, following which there was a decline until about 40 years to become relatively stable in older age classes. The gender profiles of both prevalence and intensity of microfilaraemia showed no difference between the sexes until about 15 years of age, following which both were higher in males compared to females. The distribution of microfilarial counts was overdispersed, indicating aggregation of adult worms.

Adolescent↗
PubMed1996

Cost and cost effectiveness of mass diethylcarbamazine chemotherapy for the control of bancroftian filariasis: comparison of four strategies in Tanzania.

This study examines the costs and cost effectiveness of four different mass diethylcarbamazine (DEC) chemotherapy regimens-standard dose, semi-annual single dose, low monthly dose and DEC-medicated salt-in reducing microfilarial (mf) prevalence at the community level. Costs were estimated for each intervention in relation to both ingredient and activity, by the derivation and use of detailed itemized cost menus. The most expensive and most effective strategy in reducing community mf prevalence over 2 years was DEC salt intervention, followed in order of costs by the standard, low monthly and semi-annual DEC strategies. The most cost effective strategy was the low monthly DEC treatment. Cost and sensitivity analyses, however, suggest that the optimal choice of mass DEC strategy for reducing mf is very sensitive to programme design parameters. In particular, the results demonstrate that if the salt delivery structure is simplified, DEC salt has the potential to be the dominant intervention for filariasis control. The results suggest that economies of scale considerations might militate against the adoption of this intervention for large-scale applications, unless perhaps offset by its potential for cost recovery by direct patient purchase. Further analyses require a more realistic evaluation of filariasis intervention effectiveness by addressing changes in infection intensity and by accounting for the population dynamics of parasite transmission and control.

Adolescent↗
PubMed1999

Bancroftian filariasis in an irrigation project community in southern Ghana.

An epidemiological study to document the endemicity and transmission characteristics of bancroftian filariasis was conducted in an irrigation project community in southern Ghana. In a 50% random sample of the population, the prevalence of microfilaraemia was 26.4% and the geometric mean microfilarial intensity among positives was 819 microfilariae/ml of blood. Hydrocoele was found in 13.8% of the males aged > or =18 years, and 1.4% of the residents examined, all females, had tymphoedema/elephantiasis. Detailed monitoring of the microfilarial intensity in 8 individuals over a 24-h period confirmed its nocturnal periodicity with a peak at approximately 0100 hours. The most important vector was Anopheles gambiae s.l., followed by An. funestus. The abundance of these mosquitoes and their relative importance as vectors varied considerably between the wet and the dry season. Opening of the irrigation canals late in the dry season resulted in a remarkable increase in the population of An. gambiae (8.3% of which carried infective filarial larvae) to levels comparable to those seen during the wet season, suggesting that the irrigation project is responsible for increased transmission of lymphatic filariasis in the community.

Adolescent↗
PubMed1999

Bancroftian filariasis on Pemba Island, Zanzibar, Tanzania: an update on the status in urban and semi-urban communities.

Cross-sectional clinical, parasitological and entomological surveys for bancroftian filariasis were conducted in Konde, Chake Chake and Kengeja, three urban and semiurban communities on Pemba Island, and the results were compared with similar surveys done 15 years earlier. The overall prevalences of clinical manifestations among males aged 15 years or more (n = 614) was remarkably similar to those recorded 15 years earlier: elephantiasis 1.4% in 1975 and 1.1% in 1990; hydrocele, 22.4% and 21.8%, respectively. However, when the communities were compared individually, there was a reduction in the hydrocele prevalence in Konde from 22.4% to 11.5% and an increase in Kengeja from 27.0% to 35.5%. The overall microfilarial prevalence found during night blood surveys of all individuals aged 1 year or more (n = 2687) was 9.7%, compared to 14.2% recorded in 1975. The reduction was most pronounced in Konde. Of 1052 female mosquitoes caught with CDC light traps, 95% were Culex quinquefasciatus and 5% Anopheles gambiae s.l. Infective larvae of Wuchereria bancrofti were found only in the former. The filariasis situation in urban and semiurban communities on Pemba Island appears not to have changed considerably over the last 15 years.

Adolescent↗
PubMed2003

Antibiotic therapy in murine filariasis (Litomosoides sigmodontis): comparative effects of doxycycline and rifampicin on Wolbachia and filarial viability.

The symbiosis of filarial nematodes and rickettsial Wolbachia endobacteria has been exploited as a target for antibiotic therapy of filariasis. Depletion of Wolbachia after tetracycline treatment results in filarial sterility because of interruption of embryogenesis and inhibits larval development and adult worm viability. The aim of this study was to investigate if antibiotic intervention of BALB/c mice infected with the rodent filaria Litomosoides sigmodontis with rifampicin or the combination of rifampicin and doxycycline can be used to shorten the treatment period. Both regimens, when given over a period of 14 days initiated with infection, were sufficient to deplete Wolbachia as evidenced by immunohistology and semiquantitative PCR. Worm development and filarial load were significantly reduced in experiments followed up until 63 days p.i. The therapy inhibited embryogenesis and led to filarial sterility. In contrast, treatment with doxycycline alone for 21 days led only to a modest reduction of Wolbachia, filarial growth retardation, worm viability and fertility. In conclusion, the combination of antirickettsial drugs could be used as a suitable tool to explore the minimum duration of therapy required for the depletion of Wolbachia in parasitized hosts subsequent to the onset of patency in human and animal filariasis and the prevention of adverse reactions in human infections.

Animals↗
PubMed2003

Ocular filariasis due to Wuchereria bancrofti presenting as panuveitis: a case report.

PURPOSE: To report a case of ocular filariasis due to Wuchereria bancrofti manifesting as panuveitis. DESIGN/METHODS: Observational case report. RESULT: A 30-year-old, healthy, Asian, Indian male presented with decreased vision and panuveitis with secondary glaucoma in the right eye. Careful slit-lamp examination revealed multiple, tiny, motile larvae in the anterior chamber. Indirect ophthalmoscopy showed vitritis with plenty of vitreous membranes, and subretinal yellow lesions in the peripheral retina along with retinal pigment epithelial tracts. An aqueous tap and a peripheral blood smear isolated microfilariae of W. bancrofti. Therapy with diethyl carbamazine citrate along with systemic steroids provided symptomatic relief. CONCLUSIONS: Ocular filariasis due to W. bancrofti is very rare. It can present in an otherwise asymptomatic patient without any constitutional symptoms. Careful examination, prompt diagnosis, and early treatment can reduce ocular morbidity.

Adult↗
PubMed1986

The status of human filariasis in relation to clinical signs in endemic areas of the Niger Delta.

A study was carried out in selected parts of the Niger Delta Basin on human filariasis and its relationship to clinical signs. One hundred and seventy-six (13.0%) of 1351 individuals examined were infected with microfilaria. Forty-six percent of microfilaria positive cases had M. perstans; 25.6% had W. bancrofti, 19.3% had L. loa, and 9.0% had O. volvulus. The prevalence of filariasis increased with age. Microfilarial density was generally low, 28.4% of infected individuals had counts of 50-100 microfilaria per 20 mm3 blood, 12.5% had counts less than five microfilaria per 20 mm3 blood. Onchocerca microfilariae did not exceed five microfilaria per snip. Microfilarial density was high among individuals aged between 20 and 49 years, but declined with increasing age above 50 years. Acute clinical signs of febrile attack, sink eruptions, and chronic clinical signs of chyluria, hydrocoele, elephantiasis and ocular lesions were observed in 61.9% of infected individuals, 73.4% of clinical cases were febrile attack and skin eruptions, 5.5% were chyluria, 12.8% were elephantiasis of the leg and scrotum, 7.3% were hydrocoele and 0.9% were ocular lesions. Chronic clinical signs were more prevalent in individuals over 40 years of age.

Adolescent↗
PubMed1990

Eradication of bancroftian filariasis by diethylcarbamazine-medicated common salt on Little Kinmen (Liehyu district), Kinmen (Quemoy) Islands, Republic of China.

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.

Adolescent↗
PubMed1992

Ivermectin for the treatment of periodic malayan filariasis: a study of efficacy and side effects following a single oral dose and retreatment at six months.

Ivermectin, a new antifilarial drug and currently the drug of choice for the treatment of onchocerciasis, has been shown to be effective in bancroftian filariasis. We report here, for the first time, the efficacy and safety of the drug in the treatment of filariasis caused by periodic Brugia malayi. Sixty male, asymptomatic microfilaraemics of Alleppey district, Kerala, South India, received single oral doses of ivermectin in a double blind study. Four dosages were used: 20, 50, 100 and 200 micrograms kg-1 body weight. Clearance of microfilariae, which was not complete, began as early as 12 hours post-treatment and was maximal at the end of one month. Microfilaria levels began to rise thereafter and reached 20-50% of pretreatment levels at six months. The two higher doses (100 and 200 micrograms kg-1) were more effective in suppressing microfilaraemia at six months (P < 0.05). After six months, 32 patients were retreated using the same dose of ivermectin that they had received initially. The pattern of clearance was essentially similar to that seen during the first treatment phase and microfilaria levels were 10-35% of pretreatment levels at the end of the next six months. Twenty-eight individuals who were not retreated at six months continued to have increasing levels of microfilariae, reaching 60% of pretreatment levels at the end of the next six months. Side effects (such as fever, headache, myalgia), which were mild to moderate, were seen in most patients and were unrelated to the dose (P > 0.05) or pretreatment levels of microfilariae.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗
PubMed2000

Two-year follow-up of the microfilaraemia of asymptomatic brugian filariasis, after treatment with two, annual, single doses of ivermectin, diethylcarbamazine and albendazole, in various combinations.

Repeated, single, oral doses of combinations of ivermectin, diethylcarbamazine (DEC) or albendazole are recognized as important tools for parasite control in lymphatic filariasis. In order to assess the effects of re-treatment using these combinations in Brugia malayi infections, 40 asymptomatic microfilaraemics were re-treated at the end of the first year, with an additional, single, dose of the combination they had previously received. They were then followed-up for another year. The subjects, of both sexes and aged 14-70 years, each received a two-drug combination: ivermectin (200 micrograms/kg) with DEC (6 mg/kg); ivermectin (200 micrograms/kg) with albendazole (400 mg); or DEC (6 mg/kg) with albendazole (400 mg). The kinetics of microfilarial clearance were similar to that seen during the first treatment, the members of the two groups given DEC having less intense microfilaraemias, 1 year after the re-treatment, than those given ivermectin with albendazole (P < 0.001 for each comparison). At this time, the two DEC groups also had a higher proportion of amicrofilaraemic individuals (22 of 26) than the ivermectin + albendazole group (three of nine). There were fewer adverse reactions in all the groups after re-treatment than seen after the first treatment. In countries such as India, where there is no co-endemicity of onchocerciasis or loiasis, the options for control programmes in areas where brugian filariasis is endemic are DEC alone or DEC in combination with ivermectin or albendazole. Where there is no access to ivermectin, transmission control must be based on DEC alone or in combination with albendazole.

Adolescent↗
PubMed1998

Treatment of microfilaraemia in asymptomatic brugian filariasis: the efficacy and safety of the combination of single doses of ivermectin and diethylcarbamazine.

Although combinations of ivermectin and diethylcarbamazine (DEC) have been shown to be superior to either drug alone in the suppression of bancroftian microfilariae, their efficacy against infections with Brugia malayi has never been investigated. The present, open trial is the first on the efficacy and safety of a combination of single doses of ivermectin and DEC when used against microfilaraemias of brugian filariasis. Twenty-one, asymptomatic but microfilaraemic (109-6934 microfilariae/ml blood, with a median of 841/ml) men, aged 18-48 years, each received oral doses of ivermectin (400 micrograms/kg) and DEC (6 mg/kg) as a single treatment. Twelve hours post-treatment, 96.5%-100% of the microfilariae in each subject had been cleared and 12 of the subjects were amicrofilaraemic. A further reduction in microfilarial counts was evident 1 month post-treatment (mean clearance = 99.0%) and the counts continued to fall at least until the last follow-up, at 1 year post-treatment, when the mean clearance was 99.9% and 13 (68.4%) of the 19 subjects then investigated were amicrofilaraemic. All subjects experienced adverse reactions of one form or another, lasting for up to 48 h post-treatment; these included fever, myalgia, headache, and lethargy. Postural hypotension was recorded in two subjects and dilated, inflamed lymphatic channels were seen in another two. The combination of ivermectin and DEC demonstrated a microfilaricidal effect superior to that of either drug used alone, both in the initial rapid clearance of microfilariae and in sustaining the effect for 1 year. This finding has important implications for the control of lymphatic filariasis.

Adolescent↗
PubMed1998

The efficacy, tolerability and safety of diethylcarbamazine-fortified salt in the treatment of the microfilaraemias of brugian filariasis: an open, hospital-based study.

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.

Adolescent↗
PubMedDate not supplied

Selective primary health care: strategies for the control of disease in the developing world. VII. Filariasis.

At least 250 million people throughout the world are infected with filariae, and the number of such persons is increasing. Three species infect humans: Wuchereria bancrofti, Brugia malayi, and Brugia timori. The peak of microfilarial density in the blood usually occurs nocturnally. Transmission of filariasis is remarkably inefficient. In an endemic area, approximately 100,000 mosquito bites yearly are required for production of each new case of microfilaremia. Only a small proportion of those infected suffer any ill effects from these worms. Clinical filariasis can present with acute inflammation such as lymphangitis and lymphadenitis and with chronic lymphatic obstruction such as hydrocele and lymphedema of the limbs. Measures available for potential control include the widespread usage of mosquito nets, vector control, and chemotherapy with diethylcarbamazine. Unfortunately, the efficacy of the first of these is untested and the latter two are inadequate. More research is required on vector control, assessment of new drugs, and the development of vaccines.

Adolescent↗
PubMed1979

Eosinophilia following treatment of patients with schistosomiasis mansoni and Bancroft's filariasis.

Eosinophilia is frequently observed after treatment of patients with infections due to parasitic helminths. For definition of the characteristics and causes of post-treatment eosinophilic responses, 47 patients with Bancroft's filariasis, who were treated with diethylcarbamazine, and eight patients with schistosomiasis mansoni, who were treated with niridazole, were studied. After therapy for eight days, both groups developed significant (P less than 0.05) increases in their levels of eosinophilia, which peaked in two to four weeks. Maximal levels averaged two and one-half to three time the levels before treatment. Before therapy the number of circulating eosinophils was unrelated to intensity of infection in both groups, but after treatment, when the same relationship was examined in the larger group (the patients with filariasis), the degree of post-treatment eosinophilia was significantly correlated with the patients' worm burdens before treatment (r = 0.727; P less than 0.001). Thus, treatment of helminthic infections can provide a unique opportunity for studying eosinophil responses of humans to graded doses of antigen and has shown that acute responses are determined quantitatively by the amount of antigen initially presented to the host.

Adolescent↗
PubMed1994

A case of acquired lymphangioma due to a suspected old filariasis and a review of literature.

A 65-year-old man presented in 1992 with multiple papular lesions on the scrotum and foreskin. His medical history revealed that, at the age of 25, he was diagnosed as having filariasis and treated conservatively at a hospital in Hawaii. The histologic study of the scrotal skin showed large, dilated vascular spaces in the upper dermis lined with a single layer of endothelial cells that were negative for Factor 8-related antigen. The diagnosis was acquired lymphangioma due to a suspected old filariasis infestation, although serologic tests for filarial antibodies were negative. The paper also presents a review of the literature of acquired lymphangioma in Japan with a brief discussion of etiology and nomenclature.

Adult↗
PubMed2004

Observations on false positive reactions in the rapid NOW Filariasis card test.

The NOW Filariasis card test is a useful tool for rapid field diagnosis of Wuchereria bancrofti infection, based on detection of specific circulating filarial antigen (CFA) in the patients' blood. Concern has been raised that a high proportion of infection negative individuals develop false positive reactions in these tests when the test cards are left for a prolonged period before being examined. We carried out a survey in an endemic Tanzanian village to investigate this phenomenon. Individuals who were positive in the NOW Filariasis test at 10 min after specimen application were also positive in the TropBio ELISA for CFA, and thus appeared to be truly positive. Many of the test cards that were negative at 10 min developed a positive line later, but these lines appeared to be falsely positive when the TropBio test was used as the gold standard. Close examination revealed that true and false positivity lines could be distinguished on their shape and colour. The study thus reaffirmed that test cards should be read after 10 min to avoid false positives, but it also indicated that experienced test card users should be able to make a correct diagnosis even at a later time.

Adolescent↗