Renal abnormalities in microfilaremic patients with Bancroftian filariasis

Safety and Tolerability of Ivermectin and Albendazole Mass Drug Administration in Lymphatic Filariasis Endemic Communities of Tanzania: A Cohort Event Monitoring Study

Ivermectin and albendazole (IA) combination preventive chemotherapy to all at-risk populations is deployed to eliminate lymphatic filariasis. Although safety monitoring is imperative, data from Sub-Saharan Africa is scarce. We conducted a large-scale active safety surveillance of adverse events (AEs) following IA mass drug administration (MDA) to identify the type, incidence, and associated risk factors in Tanzania. After recording sociodemographic, clinical, and medical histories, 9640 eligible residents received single-dose IA combination preventive chemotherapy. Treatment-associated AEs were actively monitored through house-to-house visits on day 1, day 2, and day 7 of MDA. Events reported before and after MDA were cross-checked and verified to identify MDA-associated AEs. 9288 participants (96.3%) completed the seven-day safety follow-up, of whom 442 reported 719 MDA-associated AEs. The incidence of experiencing one or more type of MDA-associated AE was 4.8% (95% CI = 4.3−5.2%); this being significantly higher among those with Pre-MDA clinical events than those without (8.5% versus 4.1%, p < 0.001). AEs were mild (83.8%), moderate (15.9%), and severe (0.3%), and most resolved within 72 h. The incidence of experiencing one, two, ≥ three types of AEs were 2.8%, 1.3%, and 0.6%, respectively. The most common AEs were headache (1.23%), drowsiness (1.15%), fever (1.12%), and dizziness (1.06%). A chronic illness, or clinical manifestation of lymphatic filariasis, or being female or pre-existing clinical symptoms were independent significant predictors of AEs. IA combination preventive chemotherapy is safe and tolerable, and associated AEs are mild-to-moderate and transient, with few severe AEs. Safety monitoring during MDA campaigns in individuals with underlying clinical conditions is recommended for timely detection and management of AEs.

Filariasis presenting with bicytopenia, progressive splenomegaly and acute renal failure: An unusual case report

Extra-lymphatic manifestation of filariasis, especially as acute renal failure, is uncommon and may be clinically unsuspected. We document the case of a 60 year old elderly male who presented with bilateral pedal oedema, fatigue and abdominal distension. Investigations revealed severe anaemia, splenomegaly and acute renal failure. Bone marrow aspiration was performed to evaluate the clinical suspicion of malignancy. Out of eight smears examined, microfilaria (Brugia malayi) were identified in two. This presentation was devoid of peripheral eosinophilia. The patient was commenced on a regimen of diethylcarbamazine, on which he made a good recovery. The incidence of extra-lymphatic filariasis is largely unknown and sparsely reported. Such a presentation should be kept in mind by both clinicians and pathologists as it is potentially treatable.

Review of Dancing Parasites in Lymphatic Filariasis

Lymphatic filariasis is an infection transmitted by blood-sucking mosquitoes with filarial nematodes of the species Wuchereria bancrofti, Brugia malayi und B. timori . It is prevalent in tropical countries throughout the world, with more than 60 million people infected and more than 1 billion living in areas with the risk of transmission. Worm larvae with a length of less than 1 mm are transmitted by mosquitoes, develop in human lymphatic tissue to adult worms with a length of 7-10 cm, live in the human body for up to 10 years and produce millions of microfilariae, which can be transmitted further by mosquitoes. The adult worms can be easily observed by ultrasonography because of their size and fast movements (the so-called "filarial dance sign"), which can be differentiated from other movements (e. g., blood in venous vessels) by their characteristic movement profile in pulsed-wave Doppler mode. Therapeutic options include (combinations of) ivermectin, albendazole, diethylcarbamazine and doxycycline. The latter depletes endosymbiotic Wolbachia bacteria from the worms and thus sterilizes and later kills the adult worms (macrofilaricidal or adulticidal effect).

Adverse events following single dose treatment of lymphatic filariasis: Observations from a review of the literature

Background

WHO’s Global Programme to Eliminate Lymphatic Filariasis (LF) uses mass drug administration (MDA) of anthelmintic medications to interrupt LF transmission in endemic areas. Recently, a single dose combination of ivermectin (IVM), diethylcarbamazine (DEC), and albendazole (ALB) was shown to be markedly more effective than the standard two-drug regimens (DEC or IVM, plus ALB) for achieving long-term clearance of microfilaremia.

Objective and methods

To provide context for the results of a large-scale, international safety trial of MDA using triple drug therapy, we searched Ovid Medline for studies published from 1985–2017 that reported adverse events (AEs) following treatment of LF with IVM, DEC, ALB, or any combination of these medications. Studies that reported AE rates by treatment group were included.

Findings

We reviewed 162 published manuscripts, 55 of which met inclusion criteria. Among these, 34 were clinic or hospital-based clinical trials, and 21 were community-based studies. Reported AE rates varied widely. The median AE rate following DEC or IVM treatment was greater than 60% among microfilaremic participants and less than 10% in persons without microfilaremia. The most common AEs reported were fever, headache, myalgia or arthralgia, fatigue, and malaise.

Interpretation

Mild to moderate systemic AEs related to death of microfilariae are common following LF treatment. Post-treatment AEs are transient and rarely severe or serious. Comparison of AE rates from different community studies is difficult due to inconsistent AE reporting, varied infection rates, and varied intensity of follow-up. A more uniform approach for assessing and reporting AEs in LF community treatment studies would be helpful.

WHO’s Global Programme to Eliminate Lymphatic Filariais (LF) supports annual mass drug administration to over 400 million people in LF-endemic areas each year. Two drug combinations (either DEC or ivermectin, given with albendazole) have been recommended in most endemic areas. With the exception of well-described serious adverse events (AEs) occurring in patients with high level loiasis, severe AEs due to these medications are extremely rare. Mild to moderate AEs, however, are common, particularly in patients with active filarial infection. In this manuscript we synthesize published data on AEs following single-dose treatment of LF with ivermectin, DEC, or albendazole. This provides a background against which to compare the safety of triple drug therapy (ivermectin, DEC, and albendazole) recently endorsed by WHO, and provides a useful context for evaluating safety of new treatments for LF. The compiled data illustrate that transient, mild to moderate AEs following single-dose LF treatment are common in microfilaremic patients and are much less common in amicrofilaremic patients. They also show that passive surveillance for post-treatment AEs underestimates AE incidence and suggest that adherence to common reporting standards would improve the usefulness of AE reporting in filariasis studies.

Chiluria in a lymphatic filariasis endemic area

OBJECTIVE

To establish clinical and laboratory data of individuals presenting chyluria in endemic areas.

RESULTS

75 individuals were studied. The majority were females with an average age of 45 years residing in the Metropolitan Region of Recife. The mean time between the beginning of the presentation of chyluria and the first care service in the Serviço de Referencia Nacional em Filarioses was approximately 5 years. The most frequent urinalysis changes were hematuria (27.6%), leukocytes (21.9%) and proteinuria (10.5%). The Addis test showed mean values of 155.43 E/min/mL of cylinders, 52,892 E/min/mL of erythrocytes and 291,660 E/min/mL of leukocytes. Among recorded cases, proteinuria had a mean value of 1372.80 mg/dL in 24 h, and the presence of lymphocytes in the urine was positive in 68.3%. Among lymphatic filariasis tests, immunochromatography was positive in 16.7%, there was circulating filarial antigen determined by detection of OG4C3 antibodies in 7.7% and microfilaremia in only 1/55.

Hematuria without chyluria: It could still be due to filarial etiology

There are few reports of “microfilaria in the urine.” We report an elderly woman with gross hematuria who was being investigated for urinary tract tuberculosis. Three consecutive urine samples showed microfilaria of Wuchereria bancrofti. However, she did not have chyluria. Treatment with diethylcarbamazine cleared up the hematuria within 3 days. Chyluria, hematuria, and hematochyluria are problems of Bancroftian filariasis reported worldwide. The literature review was made to present a simplified way for management.

Efficacy, Safety, and Pharmacokinetics of Coadministered Diethylcarbamazine, Albendazole, and Ivermectin for Treatment of Bancroftian Filariasis

BACKGROUND

Available treatments for lymphatic filariasis (LF) are limited in their longterm clearance of microfilaria from the blood. The safety and efficacy of a single-dose triple-drug therapy of the antifilarial drugs diethylcarbamazine (DEC), ivermectin (IVM), and albendazole (ALB) for LF are unknown.

METHODS

We performed a pilot study to test the efficacy, safety, and pharmacokinetics of single-dose DEC, IVM, and ALB in Wuchereria bancrofti-infected Papua New Guineans. Adults were randomized into 2 treatment arms, DEC 6 mg/kg + ALB 400 mg (N = 12) or DEC 6 mg/kg + ALB 400 mg + IVM 200 μg/kg (N = 12), and monitored for microfilaria, parasite antigenemia, adverse events (AEs), and serum drug levels.

RESULTS

Triple-drug therapy induced >2-log reductions in microfilaria levels at 36 and 168 hours after treatment compared with approximately 1-log reduction with 2 drugs. All 12 individuals who received 3 drugs were microfilaria negative 1 year after treatment, whereas 11 of 12 individuals in the 2-drug regimen were microfilaria positive. In 6 participants followed 2 years after treatment, those who received 3 drugs remained microfilaria negative. AEs, particularly fever, myalgias, pruritus, and proteinuria/hematuria, occurred in 83% vs 50% of those receiving triple-drug compared to 2-drug treatment respectively (P = .021); all resolved within 7 days after treatment. No serious AEs were observed in either group. There was no significant effect of IVM on DEC or ALB drug levels.

CONCLUSIONS

Triple-drug therapy is safe and more effective than DEC + ALB for Bancroftian filariasis and has the potential to accelerate elimination of lymphatic filariasis.

CLINICAL TRIALS REGISTRATION

NCT01975441.

Progress and impact of 13 years of the global programme to eliminate lymphatic filariasis on reducing the burden of filarial disease

BACKGROUND

A Global Programme to Eliminate Lymphatic Filariasis was launched in 2000, with mass drug administration (MDA) as the core strategy of the programme. After completing 13 years of operations through 2012 and with MDA in place in 55 of 73 endemic countries, the impact of the MDA programme on microfilaraemia, hydrocele and lymphedema is in need of being assessed.

METHODOLOGY/PRINCIPAL FINDINGS

During 2000-2012, the MDA programme made remarkable achievements - a total of 6.37 billion treatments were offered and an estimated 4.45 billion treatments were consumed by the population living in endemic areas. Using a model based on empirical observations of the effects of treatment on clinical manifestations, it is estimated that 96.71 million LF cases, including 79.20 million microfilaria carriers, 18.73 million hydrocele cases and a minimum of 5.49 million lymphedema cases have been prevented or cured during this period. Consequently, the global prevalence of LF is calculated to have fallen by 59%, from 3.55% to 1.47%. The fall was highest for microfilaraemia prevalence (68%), followed by 49% in hydrocele prevalence and 25% in lymphedema prevalence. It is estimated that, currently, i.e. after 13 years of the MDA programme, there are still an estimated 67.88 million LF cases that include 36.45 million microfilaria carriers, 19.43 million hydrocele cases and 16.68 million lymphedema cases.

CONCLUSIONS/SIGNIFICANCE

The MDA programme has resulted in significant reduction of the LF burden. Extension of MDA to all at-risk countries and to all regions within those countries where MDA has not yet reached 100% geographic coverage is imperative to further reduce the number of microfilaraemia and chronic disease cases and to reach the global target of interrupting transmission of LF by 2020.

Immunopathogenesis of lymphatic filarial disease

Although two thirds of the 120 million people infected with lymph-dwelling filarial parasites have subclinical infections, ~40 million have lymphedema and/or other pathologic manifestations including hydroceles (and other forms of urogenital disease), episodic adenolymphangitis, tropical pulmonary eosinophilia, lymphedema, and (in its most severe form) elephantiasis. Adult filarial worms reside in the lymphatics and lymph nodes and induce changes that result in dilatation of lymphatics and thickening of the lymphatic vessel walls. Progressive lymphatic damage and pathology results from the summation of the effect of tissue alterations induced by both living and nonliving adult parasites, the host inflammatory response to the parasites and their secreted antigens, the host inflammatory response to the endosymbiont Wolbachia, and those seen as a consequence of secondary bacterial or fungal infections. Inflammatory damage induced by filarial parasites appears to be multifactorial, with endogenous parasite products, Wolbachia, and host immunity all playing important roles. This review will initially examine the prototypical immune responses engendered by the parasite and delineate the regulatory mechanisms elicited to prevent immune-mediated pathology. This will be followed by a discussion of the proposed mechanisms underlying pathogenesis, with the central theme being that pathogenesis is a two-step process-the first initiated by the parasite and host innate immune system and the second propagated mainly by the host's adaptive immune system and by other factors (including secondary infections).

Anti-Wolbachia Surface Protein antibodies are present in the urine of dogs naturally infected with Dirofilaria immitis with circulating microfilariae but not in dogs with occult infections

Heartworm infection (Dirofilaria immitis) can cause kidney damage due to the presence of circulating microfilariae (mf) that contribute to the production and deposit of immune complexes. It has been shown that mf are a major source of Wolbachia antigen during active infection. Here the authors compared urine samples from 19 naturally infected dogs with (mf+) and 12 without (mf-) microfilariae for the presence of proteinuria and anti-Wolbachia Surface Protein (-WSP) IgG in ELISA. Kidneys from 6 mf+ and 3 mf- dogs were also examined by anti-WSP immuno-histochemistry. All infected dogs showed proteinuria, but mf+ dogs had significantly higher values compared to mf-dogs. Mf+ dogs had optical density values for anti-WSP IgG consistently higher than established cut-off values and were significantly higher than values for mf- dogs. Kidneys from mf+ dogs showed Wolbachia+ mf in glomerular capillaries. Results strongly suggest that Wolbachia associated with circulating mf may contribute to immune-mediated kidney disease in dogs with heartworm infection.

The impact of mass drug administration and long-lasting insecticidal net distribution on Wuchereria bancrofti infection in humans and mosquitoes: an observational study in northern Uganda

BACKGROUND

Lymphatic filariasis (LF) in Uganda is caused by Wuchereria bancrofti and transmitted by anopheline mosquitoes. The mainstay of elimination has been annual mass drug administration (MDA) with ivermectin and albendazole, targeted to endemic districts, but has been sporadic and incomplete in coverage. Vector control could potentially contribute to reducing W. bancrofti transmission, speeding up progress towards elimination. To establish whether the use of long-lasting insecticidal nets (LLINs) can contribute towards reducing transmission of W. bancrofti in a setting with ongoing MDA, a study was conducted in an area of Uganda highly endemic for both LF and malaria. Baseline parasitological and entomological assessments were conducted in 2007, followed by high-coverage LLIN distribution. Net use and entomological surveys were carried out after one year, and final parasitological and entomological evaluations were conducted in 2010. Three rounds of MDA had taken place before the study commenced, with a further three rounds completed during the course of the study.

RESULTS

In 2007, rapid mapping indicated 22.3% of schoolchildren were W. bancrofti antigen positive, and a baseline survey during the same year found age-adjusted microfilaraemia prevalence was 3.7% (95% confidence interval (CI): 2.6-5.3%). In 2010, age-adjusted microfilaraemia prevalence had fallen to 0.4%, while antigenaemia rates were 0.2% in children < 5 years and 6.0% in ≥ 5 years. In 2010, universal coverage of mosquito nets in a household was found to be protective against W. bancrofti antigen (odds ratio = 0.44, 95% CI: 0.22-0.89). Prevalence of W. bancrofti larvae in anopheline mosquitoes had decreased significantly between the 2007 and 2010 surveys, but there was an apparent increase in vector densities.

CONCLUSION

A marked reduction in W. bancrofti infection and infectivity in humans was observed in the study area, where both MDA and LLINs were used to reduce transmission. The extent to which LLINs contributed to this decline is equivocal, however. Further work investigating the impact of vector control on anopheline-transmitted LF in an endemic area not benefitting from MDA would be valuable to determine the effect of such interventions on their own.

Setaria equina: in vivo effect of diethylcarbamazine citrate on microfilariae in albino rats

Although diethylcarbamazine citrate (DEC) is successful drug in eliminating human filariasis, yet, its mode of action is still debatable. Herein, the effect of DEC to treat albino rats infected with the animal filarial parasite Setaria equina was tested. Microfilarial (mf) counts and sections from liver, lung, kidney as well as spleen were investigated at different time points after treatment by light microscopy. After 45 and 300min of treatment, a significant decrease in blood mf was observed accompanied by adherence of degenerated mf to both kupffer cells and leukocyte in liver sections. In lung sections, loss of sheath was observed at 45min, while degeneration was observed at later time points. In kidney sections, more mf counts and less matrix were observed in the glomeruli at all time points after treatment. Degenerated mf were observed in spleen sections only at, late time point, 480min after treatment. In conclusion, one of the possible mechanisms by which DEC reduces blood microfilarial count is trapping larvae in organs and killing them through cellular adherence.

The economic benefits resulting from the first 8 years of the Global Programme to Eliminate Lymphatic Filariasis (2000-2007)

BACKGROUND

Between 2000-2007, the Global Programme to Eliminate Lymphatic Filariasis (GPELF) delivered more than 1.9 billion treatments to nearly 600 million individuals via annual mass drug administration (MDA) of anti-filarial drugs (albendazole, ivermectin, diethylcarbamazine) to all at-risk for 4-6 years. Quantifying the resulting economic benefits of this significant achievement is important not only to justify the resources invested in the GPELF but also to more fully understand the Programme's overall impact on some of the poorest endemic populations.

METHODOLOGY

To calculate the economic benefits, the number of clinical manifestations averted was first quantified and the savings associated with this disease prevention then analyzed in the context of direct treatment costs, indirect costs of lost-labor, and costs to the health system to care for affected individuals. Multiple data sources were reviewed, including published literature and databases from the World Health Organization, International Monetary Fund, and International Labour Organization

PRINCIPAL FINDINGS

An estimated US$21.8 billion of direct economic benefits will be gained over the lifetime of 31.4 million individuals treated during the first 8 years of the GPELF. Of this total, over US$2.3 billion is realized by the protection of nearly 3 million newborns and other individuals from acquiring lymphatic filariasis as a result of their being born into areas freed of LF transmission. Similarly, more than 28 million individuals already infected with LF benefit from GPELF's halting the progression of their disease, which results in an associated lifetime economic benefit of approximately US$19.5 billion. In addition to these economic benefits to at-risk individuals, decreased patient services associated with reduced LF morbidity saves the health systems of endemic countries approximately US$2.2 billion.

CONCLUSIONS/SIGNIFICANCE

MDA for LF offers significant economic benefits. Moreover, with favorable program implementation costs (largely a result of the sustained commitments of donated drugs from the pharmaceutical industry) it is clear that the economic rate of return of the GPELF is extremely high and that this Programme continues to prove itself an excellent investment in global health.

Disseminated microfilaremia associated with lung cyst and empyema: an autopsy report

Clinical manifestations of extralymphatic disease caused by filariasis are varied and range from symptoms due to tropical pulmonary eosinophilia to hematuria, proteinuria, splenomegaly, and rarely arthritis. Disseminated microfilaremia in association with loculated lung cyst and empyema is of rare occurrence and to the best of our knowledge has not been documented in the literature so far. We report here a case of disseminated microfilaremia due to Wuchereria bancrofti infection accompanied by a lung cyst and empyema in a 21-year-old Indian man.

The global programme to eliminate lymphatic filariasis: health impact after 8 years

BACKGROUND

In its first 8 years, the Global Programme to Eliminate Lymphatic Filariasis (GPELF) achieved an unprecedentedly rapid scale-up: >1.9 billion treatments with anti-filarial drugs (albendazole, ivermectin, and diethylcarbamazine) were provided via yearly mass drug administration (MDA) to a minimum of 570 million individuals living in 48 of the 83 initially identified LF-endemic countries.

METHODOLOGY

To assess the health impact that this massive global effort has had, we analyzed the benefits accrued first from preventing or stopping the progression of LF disease, and then from the broader anti-parasite effects ('beyond-LF' benefits) attributable to the use of albendazole and ivermectin. Projections were based on demographic and disease prevalence data from publications of the Population Reference Bureau, The World Bank, and the World Health Organization.

RESULT

Between 2000 and 2007, the GPELF prevented LF disease in an estimated 6.6 million newborns who would otherwise have acquired LF, thus averting in their lifetimes nearly 1.4 million cases of hydrocele, 800,000 cases of lymphedema and 4.4 million cases of subclinical disease. Similarly, 9.5 million individuals--previously infected but without overt manifestations of disease--were protected from developing hydrocele (6.0 million) or lymphedema (3.5 million). These LF-related benefits, by themselves, translate into 32 million DALYs (Disability Adjusted Life Years) averted. Ancillary, 'beyond-LF' benefits from the >1.9 billion treatments delivered by the GPELF were also enormous, especially because of the >310 million treatments to the children and women of childbearing age who received albendazole with/without ivermectin (effectively treating intestinal helminths, onchocerciasis, lice, scabies, and other conditions). These benefits can be described but remain difficult to quantify, largely because of the poorly defined epidemiology of these latter infections.

CONCLUSION

The GPELF has earlier been described as a 'best buy' in global health; this present tally of attributable health benefits from its first 8 years strengthens this notion considerably.

A successful outcome of gross haematuria treated with diethylcarbamazine and ivermectin

Gross haematuria caused by lymphatic filariasis has been rarely reported. An adult woman living in a filarial-endemic area presented at a hospital in Orissa, India, in July 2004, with painless gross haematuria without any associated symptoms, such as dysuria, abdominal pain and fever. Urine microscopy revealed many erythrocytes and the immunochromatographic test was positive for filarial antigenaemia. After excluding other causes of haematuria, the patient was treated with a standard dose of diethylcarbamazine for 12 days and a single dose of ivermectin (200 microg/kg) and responded well without any recurrence for 2 years of follow-up.

Antigen-specific immune complexes in urine of patients with lymphatic filariasis

Lymphatic filarial subjects with disease manifestations exhibit significantly elevated levels of immune complexes (ICs) in their circulation. The objective of the study was to explore the possible excretion of filaria-specific soluble ICs in urine of subjects with lymphatic filariasis. Paired urine (overnight) and serum samples were analyzed for complement activating filarial antigen containing immune complexes by enzyme-linked immunosorbent assay (ELISA). Antigen-specific ICs were detected in urine samples of 34% of subjects with filarial disease manifestations while the frequency of occurrence was low in microfilaremic subjects. The titer of urine ICs is significantly high in subjects with chronic filariasis as compared to microfilaria (mf) carriers. The occurrence of filaria-specific ICs in urine and their passage through the filtering structures of the kidney is suggestive of the focal or diffuse damage in those subjects. Detection of ICs in urine may provide a noninvasive means of assessing the extent of renal damage in patients with lymphatic filariasis.

Temporary shift of microfilariae of Brugia pahangi from the lungs to muscles in Mongolian jirds, Meriones unguiculatus, after a single injection of diethylcarbamazine

A single-dose treatment with diethylcarbamazine (DEC) reduced microfilaria (mf) counts of Brugia pahangi by >90% at 30 min post-treatment in Mongolian jirds (Meriones unguiculatus). The reduction was followed by a rapid increase in microfilaremia, with the count reaching pretreatment level in 3 hr. The mechanisms behind this temporary reduction of mf were investigated. Without treatment, mf accumulated in the lungs. At 30 min post-treatment, they had moved from the lungs and accumulated in the muscle. At the same time, electron microscopy revealed many mf in the muscle interstitium. DEC concentrations at 30 min were much lower in the muscle (12.2 microg/g of tissue) than in the lungs, liver, and kidneys (19.8-40.7 microg/g), all of which declined to < 0.6 microg/g by 3 hr. The presence of mf in the muscle would be advantageous for avoiding high DEC concentrations, and their extravascular location could prevent attack by host effector cells.

Doxycycline reduces plasma VEGF-C/sVEGFR-3 and improves pathology in lymphatic filariasis

Lymphatic filariasis is a disease of considerable socioeconomic burden in the tropics. Presently used antifilarial drugs are able to strongly reduce transmission and will thus ultimately lower the burden of morbidity associated with the infection, however, a chemotherapeutic principle that directly induces a halt or improvement in the progression of the morbidity in already infected individuals would constitute a major lead. In search of such a more-effective drug to complement the existing ones, in an area endemic for bancroftian filariasis in Ghana, 33 microfilaremic and 18 lymphedema patients took part in a double-blind, placebo-controlled trial of a 6-wk regimen of 200 mg/day doxycycline. Four months after doxycycline treatment, all patients received 150-200 microg/kg ivermectin and 400 mg albendazole. Patients were monitored for Wolbachia and microfilaria loads, antigenemia, filarial dance sign (FDS), dilation of supratesticular lymphatic vessels, and plasma levels of lymphangiogenic factors (vascular endothelial growth factor-C [VEGF-C] and soluble vascular endothelial growth factor receptor-3 [(s)VEGFR-3]). Lymphedema patients were additionally monitored for stage (grade) of lymphedema and the circumferences of affected legs. Wolbachia load, microfilaremia, antigenemia, and frequency of FDS were significantly reduced in microfilaremic patients up to 24 mo in the doxycycline group compared to the placebo group. The mean dilation of supratesticular lymphatic vessels in doxycycline-treated patients was reduced significantly at 24 mo, whereas there was no improvement in the placebo group. Preceding clinical improvement, at 12 mo, the mean plasma levels of VEGF-C and sVEGFR-3 decreased significantly in the doxycycline-treated patients to a level close to that of endemic normal values, whereas there was no significant reduction in the placebo patients. The extent of disease in lymphedema patients significantly improved following doxycycline, with the mean stage of lymphedema in the doxycycline-treated patients being significantly lower compared to placebo patients 12 mo after treatment. The reduction in the stages manifested as better skin texture, a reduction of deep folds, and fewer deep skin folds. In conclusion, a 6-wk regimen of antifilarial treatment with doxycycline against W. bancrofti showed a strong macrofilaricidal activity and reduction in plasma levels of VEGF-C/sVEGFR-3, the latter being associated with amelioration of supratesticular dilated lymphatic vessels and with an improvement of pathology in lymphatic filariasis patients.

Lymphatic Filariasis: Treatment, Control and Elimination

Lymphatic filariasis (LF) is a disease not just treatable or controllable; it is a disease that can be eliminated. Indeed, LF is currently the target of a major global initiative to do just that; a few visionaries of the past 50 years did hypothesize that LF elimination was feasible. However, for most of the scientific and global health communities, the elimination of such a broadly disseminated, mosquito-borne disease has seemed highly unlikely. During the past decade, however, both the treatment strategies and the control strategies for LF have undergone profound paradigm shifts-all because of a rapid increase in knowledge and understanding of LF that derived directly from a series of remarkable achievements by the scientific and medical research communities. As a result, a public health dimension with a focus on affected populations, now supplements the earlier, predominantly patient-oriented clinical approach to LF. The early uncertainties, then the essential steps leading to this change in outlook are outlined below, followed by descriptions of the new strategy for LF elimination, the Global Programme created to attain this goal and the successes achieved to date.

Treatment strategies underpinning the global programme to eliminate lymphatic filariasis

Lymphatic filariasis (LF) is a disease targeted for elimination. The global strategy is a once-yearly, single-dose, two-drug regimen utilised by communities at risk for LF, with the goal of reaching 80% population coverage yearly, for at least 5 years, in order to interrupt transmission of LF. Where onchocerciasis is co-endemic, the regimen is ivermectin 200 - 400 microg/kg plus albendazole 400mg; elsewhere, the regimen should be diethylcarbamazine 6 mg/kg plus albendazole 400mg. This paper reviews in detail the evidence for the efficacy and safety of these two-drug regimens underpinning the global strategy and makes recommendations for future developments in chemotherapy for LF, focusing on unresolved issues. These include optimal frequency, duration and end point of treatment, tools for monitoring successful therapy and means for detecting the potential development of resistance to any of the three antifilarial drugs on which the Global Programme to Eliminate LF depends.

A produção do conhecimento científico e as políticas de saúde pública: reflexões a partir da ocorrência da filariose na cidade do Recife, Pernambuco, Brasil

O artigo discute a relação entre a produção científica sobre a ocorrência da filariose bancroftiana no Brasil e o processo de formulação e implementação da política de saúde voltada ao seu controle. Para tanto, realiza uma revisão da produção do conhecimento e das políticas específicas, no período compreendido desde a criação do Programa de Combate à Filariose, em meados do século passado, até a criação do SUS, no marco da descentralização do controle das endemias. Centrando suas observações empíricas na ambiência da cidade do Recife, espaço urbano no qual ainda prevalece a filariose, ressalta os processos institucionais e destaca o papel dos distintos atores neles envolvidos. Partindo da hipótese de que se até à primeira metade do século vinte faltavam o conhecimento científico e o desenvolvimento tecnológico para o controle do problema, a seguir, quando esses avanços são disponibilizados, outros requerimentos, agora do campo da política, irão se impor, atuando como determinantes da persistência da endemia na cidade.

A filariose bancroftiana no município de Moreno - Pernambuco, Brasil

No Brasil, estima-se que 49 mil pessoas estejam infectadas pela Wuchereria bancrofti, residindo em três áreas consideradas endêmicas: Maceió-AL, Belém-PA e Região Metropolitana do Recife-PE; esta última apresenta a maior casuística no país. Este estudo tem como objetivo identificar o limite entre municípios com e sem transmissão ativa, em Pernambuco. Para tal foi realizado um estudo seccional no município de Moreno, localizado na Região Metropolitana do Recife. O inquérito epidemiológico foi constituído de entrevistas utilizando questionários fechados contendo informações relacionadas à filariose e à pesquisa parasitológica. Dentre os 2.513 exames realizados, dois casos foram detectados, ambos provenientes do Recife-PE. Quanto à manifestação clínica, 65 (2,6%) indivíduos relataram queixas correlatas com filariose. Em relação ao tratamento prévio para filariose, 24 pessoas (0,9%) afirmaram já terem tomado a dietilcarbamazina. A importância deste trabalho decorre do desconhecimento da extensão da endemia na Região Metropolitana do Recife e da constatação de que Moreno apresenta os componentes para manter o ciclo parasitário. Desta forma, a vigilância epidemiológica municipal deverá identificar as áreas com maior risco de transmissão e assim criar estratégias para evitar sua fixação.

Microscopic haematuria as an occult filarial infection in bhubaneshwar an endemic area for bancroftian filariasis

Sera samples of 7 microscopic haematuria cases collected before and after treatment with Diethylcarbamazine citrate, (DEC), 9 microfilaraemic cases and 19 endemic normal individuals were analysed for filarial antigen and IgG antibody levels. Filarial antigen was detected in 5 of the 7 microscopic haematuria cases, of which 3 turned negative for antigen after treatment with DEC. While none of the 7 haematuria cases were positive for filarial IgG antibodies, before the DEC treatment, all of them turned positive after DEC treatment. The sensitivity and specificity values(to detect mf +ve cases) were 89% and 90% respectively for the detection of filarial antigen and 78% and 95% respectively for the detection of filarial IgG antibodies.

Lymphatic filariasis: new insights into an old disease

Lymphatic filariasis has afflicted people in the tropical areas of the world for thousands of years but even up to comparatively recent times it has been poorly understood and its importance under recognised. In the last 2 decades or so there has been a flurry of activity in filariasis research, which has provided new insights into the global problem of filariasis, the pathogenesis of filarial disease, diagnosis and control.

Serum ferritin, alpha-tocopherol, beta-carotene and retinol levels in lymphatic filariasis

Based on a cross-sectional study conducted among 100 adults in 1993 in Tanga, Tanzania, the relationship between Wuchereria bancrofti infection and markers of iron, vitamin A and vitamin E status was assessed. Potential predictors assessed were elephantiasis, hydrocoele, W. bancrofti microfilaria intensity and antigen concentration, and intensity of Schistosoma haematobium, hookworm, Trichuris trichiura and Ascaris lumbricoides infection, while controlling for age, sex and elevated serum alpha-1 antichymotrypsin. Of the 100 adults, 62 had W. bancrofti antigenaemia and 43 microfilaraemia, and 21 had elephantiasis. Of the 64 males, 31 had hydrocoele. W. bancrofti microfilaria intensity was a positive predictor of serum ferritin and a negative predictor of serum alpha-tocopherol. In contrast, negative relationships observed between W. bancrofti microfilaria intensity and serum beta-carotene and retinol were not significant. Neither antigen concentration nor clinical manifestations were predictors of micronutrient status. Intensity of hookworm infection was associated with lower serum ferritin. S. haematobium egg output was not a significant predictor of serum ferritin, but was a positive predictor of serum beta-carotene. In conclusion, W. bancrofti microfilaria intensity was associated with higher serum ferritin, but lower serum alpha-tocopherol. The associations probably reflect increased oxidative stress due to microfilariaehost interactions, which could play a role in the pathogenesis.

[Recommendations for the treatment of bancroftian filariasis in symptomless and diseased patients]

The goals of treatment for lymphatic filariasis are: to prevent, reverse, or halt progression of disease; and to interrupt transmission of the parasite. Selecting the appropriate therapy for the patient with lymphatic filariasis requires knowledge of the various clinical features of filarial disease and their pathogenesis. In the past, treatment of lymphatic filariasis has focused primarily on antiparasitic chemotherapy; however, for many of the acute and chronic manifestations of lymphatic filariasis, it is now clear that supportive or other forms of clinical care are even more important than antiparasitic medication in order to prevent worsening of the disease. Regardless of the clinical manifestations of filarial disease in a particular patient, the following three components of treatment should, in general, be considered: supportive or disease specific clinical care (including hygiene and diet), patient education and counseling and finally, antiparasitic chemotherapy with diethylcarbamazine (DEC) and/or the combination of DEC with ivermectin. The authors also describe the proportional efficacy of diethylcarbamazine and ivermectin, alone or in combination, for use in mass treatment aiming at transmission interruption and the use of hygiene as a public health approach for lymphedema prevention.

Lymphatic filariasis of the ovary and mesosalpinx

We report 2 cases of filariasis, one in the ovary and the other in the mesosalpinx. In the first case, the patient underwent panhystrectomy and in the second case, right ovarian cystectomy with right salpingectomy were performed under general anaesthesia. Histopathology showed adult filarial worms in the dilated lymphatics of the right ovary, in the first case and in the mesosalpinx, in the second case. Both patients presented with complaints related to gynecological problems and not filariasis. Reports of filariasis in the literature and possible treatments and prevention strategies are also discussed.

Lymphatic filariasis: new insights and prospects for control

Although lymphatic filariasis remains among the major causes of disability among the tropical infectious diseases, dramatic advances have been made in the approach to its diagnosis, epidemiology and treatment, in our understanding of the molecular composition of the parasites that cause these infections, and in the factors underlying the pathology seen. Superimposing the tools of modern epidemiology, immunology, and molecular biology on field-based clinical trials has allowed the emergence of the concept of elimination of lymphatic filariasis. Much of the important new research emphasizes parasite development in the context of the host response, the importance of both the adult worm and other factors in the pathogenesis of lymphatic filarial disease, the role the Wolbachia endosymbiont holds as both a target for drug treatment and in inducing post-treatment reactions, and the various principles underlying the implementation of control programs.

Lymphatic filariasis: an infection of childhood

Lymphatic filariasis (LF), already recognized as a widespread, seriously handicapping disease of adults, was generally thought to occur only sporadically in children. New, highly sensitive diagnostic tests (antigen detection, ultrasound examination) now reveal, however, that LF is first acquired in childhood, often with as many as one-third of children infected before age 5. Initial damage to the lymphatic system by the parasites generally remains subclinical for years or gives rise only to non-specific presentations of adenitis/adenopathy; however, especially after puberty the characteristic clinical features of the adult disease syndromes (lymphoedema, hydrocoele) manifest themselves. Recognizing that LF disease starts its development in childhood has immediate practical implications both for management and prevention of the disease in individual patients and for the broader public health efforts to overcome all childhood illnesses. For the new World Health Organization (WHO)-supported, public-/private-sector collaboration (Global Alliance) to eliminate LF through once-yearly drug treatment, this recognition means that children will be not only the principal beneficiaries of LF elimination but also a population particularly important to target in order for the programme to achieve its twin goals of interrupting transmission and preventing disease.

Regulation of the immune response in lymphatic filariasis: perspectives on acute and chronic infection with Wuchereria bancrofti in South India

Delineating the immune responses in lymphatic filariasis has been complicated not only by the rapidly expanding knowledge of new immunological mediators and effortors, but also by new methodologies (in particular, circulating filarial antigen detection) for defining and categorizing filarial-infected individuals. By using assays for circulating antigen in the sera collected as part of the many immunological studies performed on individuals in a Wuchereria bancrofti-endemic region of South India, we have attempted to explore the influence of patency on the antigen-driven proliferative and cytokine responses seen in peripheral blood mononuclear cells of individuals with varying clinical manifestations of lymphatic filarial infection. Moreover, we have provided perspectives on the differences between acute and chronic infection with W. bancrofti and suggested mechanisms that may underly the modulation of the immune response as patency occurs.

Evaluation of the ICT whole blood antigen card test to detect infection due to nocturnally periodic Wuchereria bancrofti in South India

The commercially available ICT Card Test for bancroftian filariasis was evaluated for its sensitivity and specificity in detecting microfilaria carriers among 189 individuals each in filariasis-endemic and nonendemic areas in South India, and compared to both conventional night blood finger prick thick blood smear examination and venous blood membrane filtration. Though the specificity of the test was 100% in comparison to both, the sensitivity was 98.5% against the finger prick thick blood smear and 71.9 compared to the membrane filtration technique. Similarly, the positive predictive value was 100% against both techniques, but the negative predictive values were 99.5% against the finger prick thick blood smear and 88.3% compared to the membrane filtration technique. The test's lower sensitivity compared to the filtration technique requires further investigation.

[Rational for morbidity management in bancroftian filariasis endemic areas]

Selection of the most appropriate therapy for the patient with bancroftian filariasis requires a knowledge of the diverse clinical characteristics of filarial disease and their pathogenesis. As a result of new diagnostic tests and clinical advances, our understanding of bancroftian filariasis has changed rapidly, as have our ideas about treatment. In the past, it was believed that elephantiasis was caused by an immunologic reaction of the host to the filarial parasite. From this perspective, elephantiasis was seen as the endpoint of an unalterable relationship between the host and the parasite, and given the absence of effective medication or procedures, affected individuals were considered "immunologically predisposed" to this end-stage disease. In the last few years, however, new evidence has suggested that lymphedema and elephantiasis have another etiologic agent. Namely, the principal factor in the evolution of lymphedema and elephantiasis is the involvement of recurrent secondary bacterial infections. Today, it is clear that other forms of supportive therapy (including education and psychological counseling) are necessary and are often more important than antiparasitic drugs.

Glomerulopathy associated with parasitic infections

Although parasitic infections do not usually present with disturbance in renal function, glomerular lesions can be seen in most of these infections. The glomerular lesions observed in parasitic infections cover the whole range of glomerular lesions known, but most of them are proliferative. Little is known of the exact pathogenic mechanisms. In this review, we try to explain the glomerular lesions associated with parasitic infections in terms of the specific immunologic events observed during these diseases against the background of recent developments in the general knowledge of the pathogenesis of glomerular disease.

Glomerulopathy associated with parasitic infections

Although parasitic infections do not usually present with disturbance in renal function, glomerular lesions can be seen in most of these infections. The glomerular lesions observed in parasitic infections cover the whole range of glomerular lesions known, but most of them are proliferative. Little is known of the exact pathogenic mechanisms. In this review, we try to explain the glomerular lesions associated with parasitic infections in terms of the specific immunologic events observed during these diseases against the background of recent developments in the general knowledge of the pathogenesis of glomerular disease.

Extralymphatic disease due to bancroftian filariasis

Infection with Wuchereria bancrofti, Brugia malayi, or B. timori not only affects the structure and function of lymphatic vessels but is also associated with extralymphatic pathology and disease. Because it is now possible to detect living adult worms by ultrasonography, much emphasis is placed on lymphatic pathology. However, the finding of renal damage in asymptomatic microfilaremic carriers has led to increased recognition of the importance of extralymphatic clinical manifestation in bancroftian filariasis. The authors present a number of clinical syndromes that may be manifestations of extralymphatic filarial disease and discuss possible mechanisms that cause these conditions. The main purpose of this paper is to raise the awareness of students and physicians of the prevalence and the importance of extralymphatic disease in bancroftian filariasis so that it is diagnosed and treated properly and also to alert for the need of additional research in this area.

New tools for diagnosis and monitoring of bancroftian filariasis parasitism: The polynesian experience

Bancroftian filariasis is endemic in French Polynesia and control programs with diethylcarbamazine, started in the 1950s, led to a sharp reduction of the microfilaria prevalence. Consequently, the control program was interrupted in 1982. Ten years later, however, the incidence of the parasitism again reached pre-control levels (20-30% microfilaremia in some islands), indicating that the adult worms (for which no diagnostic tool was available) had persisted. Apart from research on chemotherapy strategies, the Institut Malardé has been actively involved in developing and evaluating more-powerful diagnostic tools than the unique detection of microfilariae by blood smear examination. These include: (1) the detection of adult worm circulating antigens in humans, and (2) the detection of Wuchereria bancrofti larvae in mosquitoes, using DNA probes. In this paper, Luc Nicolas reviews the available diagnostic tools to detect W. bancrofti and their implementation in epidemiological areas, based on the Polynesian experience.

[Lymphatic filariasis: a potentially eradicable disease]

The recent demonstration that single-dose ivermectin, diethylcarbamazine, or a combination of these drugs can profoundly suppress Wuchereria bancrofti and Brugia malayi microfilaremia for periods of six months to two years has led to renewed hope that transmission can be interrupted and lymphatic filariasis eradicated. Based in part on the availability of these new chemotherapeutic tools, the International Task Force for Disease Eradication recently identified lymphatic filariasis as one of the few diseases that could potentially be eradicated. Thus, control programs based on mass treatment (whether supplemented or not by vector control) have begun to be implemented in some endemic areas. We provide a brief review of available anti-filarial drugs for use in humans, including their tolerance and efficacy.

[Diethylcarbamazine in the treatment of Bancroft's filariasis]

The authors presented a detailed review about the treatment of bancroftian filariasis with diethylcarbamazine. The interesting aspects about the drug discovery and the basic concepts about its pharmacology were reported in a summarised form. On the other hand, emphasis was made about the speculation done by several authors about the intriguing findings regarding its efficacy reported in the literature. Latter, it was brought the new advances about the disease, as for example, the visualization by ultrasound of living Wuchereria bancrofti adult worm on its natural host--the human being. This made possible the comprehension of several paradoxical issues reported, focusing the treatment of infection using diethylcarbamazine. So far, because of the lack of ideal drug with micro and macrofilaricidal properties, together with the new understand about the disease and the new parameters for monitoring the efficacy of the drug, diethylcarbamazine has back its importance conquered at the begin of its discovery, almost fifth years ago.

Re-assessing the global prevalence and distribution of lymphatic filariasis

This paper estimates the global burden of lymphatic filariasis based on a review of the published literature on infection and disease surveys. A method for aggregating and projecting prevalence data from individual studies to national, regional and global levels, which also facilitates the estimation of gender and age-specific burdens, is presented. The method weights in favour of the larger, and hence presumbably more reliable, studies and relies on estimated empirical relationships between gender, age, infection and disease in order to correct studies with incomplete data. The results presented here suggest that although the overall prevalence of filariasis cases is 2.0% globally (approximately totalling 119 million cases), the disease continues to be of considerable local importance, particularly in India and Sub-Saharan Africa. Estimates by age and gender clearly show that, unlike other helminth infections, filariasis is mainly a disease of the adult and older age-classes and appears to be more prevalent in males. This work suggests that the derivation of more accurate estimates of the burden of filariasis will require a better understanding of both the epidemiology and the spatial aspects of infection and disease. It also suggests that filariasis is preventable based on a geographically targeted strategy for control.

Immunoregulation in human lymphatic filariasis: the role of interleukin 10

In humans with lymphatic filariasis microfilaremia is associated with a parasite antigen-specific hyporesponsiveness when assessed by cell proliferation and secretion of interleukin-2 and interferon-gamma. Hyporesponsiveness in these individuals is not only parasite antigen-specific but appears to be limited to Th1-type responses. Th2 mediated responses such as IL-5 secretion and IgE antibody production to parasite antigens are generally strong and usually no different than those seen in immunologically more reactive amicrofilaremic individuals with chronic lymphatic pathology. The mechanisms by which Th1 responses are inhibited have not yet been elucidated, but some studies suggest that down-regulatory cytokines such as IL-10 may be involved in this process. Mononuclear cells from microfilaremic individuals have been found to secrete greater quantities of IL-10 spontaneously and in response to parasite antigens. In this review, mechanisms by which IL-10 may be induced by the parasite and the mode by which IL-10 may regulate parasite antigen-specific Th1 responses in these individuals are discussed.