Filariasis is prevalent in tropical and subtropical areas and is endemic in regions of India. Lymphatic filariasis in India is caused mainly by two species of nematodes: Wuchereria bancrofti and Brugia malayi, which invade the human lymphatic system. We report two cases of superficial cystic lesions of the upper limb revealed on fine needle aspiration (FNA) to be clinically unsuspected filariasis. Despite similar aetiologies, both cases revealed variations in aspirate nature, smear morphology and peripheral blood findings. FNA provides definitive diagnosis and is an important tool for diagnosing soft tissue swellings owing to filariasis.

BACKGROUND:

Lymphatic filariasis is a major vector-borne disease and India bears 81% of the filariasis burden in South East Asia. Screening and mass drug administration is carried out in 11 known endemic districts of Madhya Pradesh. However, regular monitoring is not carried out in non-endemic areas.

METHODS:

Cross sectional surveys were carried out to examine blood samples for filariasis. Entomological surveys were conducted for infective mosquitoes.

RESULTS:

Altogether, 24 of 252 samples were positive for filariasis with a mean microfilaria count of 0.8. The entomological investigations showed 7.4% infection and 1.4 % infectivity rates in vectors.

CONCLUSION:

This study reveals the emergence of new foci of lymphatic filariasis in Madhya Pradesh. We conclude that filariasis surveys should be carried out in non-endemic areas of India to achieve the goal of elimination.

OBJECTIVE:

To report the prevalence of lymphatic filariasis and intestinal parasitic infections in school-aged children living in a filariasis endemic area and discuss about the therapeutic regimen adopted in Brazil for the large-scale treatment of filariasis.

METHODS:

A cross-sectional study including 508 students aged 5-18 years old, enrolled in public schools within the city of Olinda, Pernambuco. The presence of intestinal parasites was analyzed using the Hoffman, Pons and Janer method on 3 stool samples. The diagnosis of filarial infection was performed using the rapid immunochromatographic technique (ICT) for the antigen, and the polycarbonate membrane filtration for the presence of microfilariae. Descriptive statistics of the data was performed using EpiInfo version 7.

RESULTS:

The prevalence of filariasis was 13.8% by ICT and 1.2% by microfilaraemia, while intestinal parasites were detected in 64.2% of cases. Concurrent diagnosis of filariasis and intestinal parasites was 9.4%, while 31.5% of students were parasite-free. Among individuals with intestinal parasites, 55% had one parasite and 45% had more than one parasite. Geohelminths occurred in 72.5% of the parasited individuals. In the group with filarial infection the prevalence of soil-transmitted helminthiasis was 54.5%.

CONCLUSIONS:

The simultaneous diagnosis of filariasis and intestinal parasites as well as the high frequency of geohelminths justify the need to reevaluate the treatment strategy used in the Brazilian filariasis large-scale treatment program.

Backgroud: Lymphatic filariasis constitutes a major public health issue in French Polynesia. Diagnosis has been revolutionized with the availability of circulating filarial antigen (CFA) tests which are easy to perform but are costly. Filariasis is responsible for acquired eosinophilia and eosinophil blood count (EBC) is commonly used as a screening tool.

METHODS:

We retrospectively analysed all the results of EBCs and CFA tests performed in our laboratory over a 2-year period. We calculated the prevalence of antigenemia for nine different eosinophil cutoffs. We calculated the number of patients detected by CFA testing and the number of estimated CFA-positive patients according to their EBC.

RESULTS:

Over a 2-year period, we detected 7503 eosinophilic patients. For an EBC above 500/mm(3), the prevalence of positive CFA was 25·78% and the estimated number of positive CFA patients was 1934. During the same period, as CFA determination is not routinely performed, only 141 patients were detected and treated.

CONCLUSION:

Our current strategy against lymphatic filariasis which combines annual mass drug administration, systematic treatment of antigenemic and microfilaraemic patients, and vector control; failed to reach the target of 1% prevalence. Unfortunately, mainly for economical reasons, the antigenemia cannot be determined for all patients. In complement to existing strategy, we propose an additional action based on the treatment of eosinophilic patients in order to reduce the filariasis prevalence in our country.

Helminth parasites use antioxidant defence strategies for survival during oxidative stress due to free radicals in the host. Accordingly, tissue-dwelling filarial parasites counteract host responses by releasing a number of antioxidants. Targeting these redox regulation proteins together, would facilitate effective parasite clearance. Here, we report the combined effect of protective immune responses trigged by recombinant Wuchereria bancrofti thioredoxin (WbTRX) and thioredoxin peroxidase (WbTPX) in an experimental filarial model. The expression of WbTRX and WbTPX in different stages of the parasite and their cross-reactivity were analysed by enzyme-linked immunosorbent assay (ELISA). The immunogenicity of recombinant proteins and their protective efficacy were studied in animal models when immunized in single or cocktail mode. The antigens showed cross-reactive epitopes and induced high humoral and cellular immune responses in mice. Further, parasite challenge against Brugia malayi L3 larvae in Mastomys coucha conferred significant protection of 57% and 62% against WbTRX and WbTPX respectively. The efficacy of L3 clearance was significantly higher (71%) (P <  0.001) when the antigens were immunized together, showing a synergistic effect in multiple-mode vaccination. Hence, the study suggests WbTRX and WbTPX to be attractive vaccine candidates when immunized together and provides a tandem block for parasite elimination in the control of lymphatic filariasis.

Neglected tropical diseases are co-endemic in many areas of the world, including sub Saharan Africa. Currently lymphatic filariasis (albendazole/ivermectin) and trachoma (azithromycin) are treated separately. Consequently, financial and logistical benefit can be gained from integration of preventive chemotherapy programs in such areas. METHODOLOGYFINDINGS: 4 villages in two co-endemic districts (Kolondièba and Bougouni) of Sikasso, Mali, were randomly assigned to coadministered treatment (ivermectin/albendazole/azithromycin) or standard therapy (ivermectin/albendazole with azithromycin 1 week later). These villages had previously undergone 4 annual MDA campaigns with ivermectin/albendazole and 2 with azithromycin. One village was randomly assigned to each treatment arm in each district. There were 7515 eligible individuals in the 4 villages, 3011(40.1%) of whom participated in the study. No serious adverse events occurred, and the majority of adverse events were mild in intensity (mainly headache, abdominal pain, diarrhoea and "other signs/symptoms"). The median time to the onset of the first event, of any type, was later (8 days) in the two standard treatment villages than in the co-administration villages. Overall the number of subjects reporting any event was similar in the co-administration group compared to the standard treatment group [18.7% (281/1501) vs. 15.8% (239/1510)]. However, the event frequency was higher in the coadministration group (30.4%) than in the standard treatment group (11.0%) in Kolondièba, while the opposite was observed in Bougouni (7.1% and 20.9% respectively). Additionally, the overall frequency of adverse events in the co-administration group (18.7%) was comparable to or lower than published frequencies for ivermectin+albendazole alone.These data suggest that co-administration of ivermectin+albendazole and azithromycin is safe; however the small number of villages studied and the large differences between them resulted in an inability to calculate a meaningful overall estimate of the difference in adverse event rates between the regimens. Further work is therefore needed before co-administration can be definitively recommended.ClinicalTrials.gov; NCT01586169.

Strongyloides stercoralis infections have a worldwide distribution with a global burden in terms of prevalence and morbidity that is largely ignored. A public health response against soil-transmitted helminth (STH) infections should broaden the strategy to include S. stercoralis and overcome the epidemiological, diagnostic, and therapeutic challenges that this parasite poses in comparison to Ascaris lumbricoides, Trichuris trichiura, and hookworms. The relatively poor sensitivity of single stool evaluations, which is further lowered when quantitative techniques aimed at detecting eggs are used, also complicates morbidity evaluations and adequate drug efficacy measurements, since S. stercoralis is eliminated in stools in a larval stage. Specific stool techniques for the detection of larvae of S. stercoralis, like Baermann's and Koga's agar plate, despite superiority over direct techniques are still suboptimal. New serologies using recombinant antigens and molecular-based techniques offer new hopes in those areas. The use of ivermectin rather than benzimidazoles for its treatment and the need to have curative regimens rather than lowering the parasite burden are also unique for S. stercoralis in comparison to the other STH due to its life cycle, which allows reproduction and amplification of the worm burden within the human host. The potential impact on STH of the benzimidazoles/ivermectin combinations, already used for control/elimination of lymphatic filariasis, should be further evaluated in public health settings. While waiting for more effective single-dose drug regimens and new sensitive diagnostics, the evidence and the tools already available warrant the planning of a common platform for STH and S. stercoralis control.

With the Global Program for the Elimination of Lymphatic Filariasis continuing to make strides towards disease eradication, many locations endemic for the causative parasites of lymphatic filariasis are realizing a substantial decrease in levels of infection and rates of disease transmission. However, with measures of disease continuing to decline, the need for time-saving and economical molecular diagnostic assays capable of detecting low levels of parasite presence is increasing. This need is greatest in locations co-endemic for both Wuchereria bancrofti and Brugia parasites because testing for both causative agents individually results in significant increases in labor and reagent costs. Here we describe a multiplex, TaqMan-based, real-time PCR assay capable of simultaneously detecting W. bancrofti and B. malayi DNA extracted from human bloodspots or vector mosquito pools. With comparable sensitivity to established singleplex assays, this assay provides significant cost and labor savings for disease monitoring efforts in co-endemic locations.

An estimated 100 million people in the Latin American and Caribbean (LAC) region live on less than US$2 per day, while another 46 million people in the US live below that nation's poverty line. Almost all of the 'bottom 100 million' people suffer from at least one neglected tropical disease (NTD), including one-half of the poorest people in the region infected with hookworms, 10% with Chagas disease, and up to 1-2% with dengue, schistosomiasis, and/or leishmaniasis. In the US, NTDs such as Chagas disease, cysticercosis, toxocariasis, and trichomoniasis are also common among poor populations. These NTDs trap the poorest people in the region in poverty, because of their impact on maternal and child health, and occupational productivity. Through mass drug administration (MDA), several NTDs are on the verge of elimination in the Americas, including lymphatic filariasis, onchocerciasis, trachoma, and possibly leprosy. In addition, schistosomiasis may soon be eliminated in the Caribbean. However, for other NTDs including hookworm infection, Chagas disease, dengue, schistosomiasis, and leishmaniasis, a new generation of 'anti-poverty vaccines' will be required. Several vaccines for dengue are under development by multinational pharmaceutical companies, whereas others are being pursued through non-profit product development partnerships (PDPs), in collaboration with developing country manufacturers in Brazil and Mexico. The Sabin Vaccine Institute PDP is developing a primarily preventive bivalent recombinant human hookworm vaccine, which is about to enter phase 1 clinical testing in Brazil, as well as a new therapeutic Chagas disease vaccine in collaboration with several Mexican institutions. The Chagas disease vaccine would be administered to seropositive patients to delay or prevent the onset of Chagasic cardiomyopathy (secondary prevention). Together, MDA and the development of new anti-poverty vaccines afford an opportunity to implement effective control and elimination strategies for the major NTDs in the Americas.

BACKGROUND:

The heterogeneity of malaria transmission makes widespread elimination a difficult goal to achieve. Most of the current vector control measures insufficiently target outdoor transmission. Also, insecticide resistance threatens to diminish the efficacy of the most prevalent measures, indoor residual spray and insecticide treated nets. Innovative approaches are needed. The use of endectocides, such as ivermectin, could be an important new addition to the toolbox of anti-malarial measures. Ivermectin effectively targets outdoor transmission, has a novel mechanism of action that could circumvent resistance and might be distributed over the channels already in place for the control of onchocerciasis and lymphatic filariasis.

METHODS:

The previous works involving ivermectin and Anopheles vectors are reviewed and summarized. A review of ivermectin's safety profile is also provided. Finally three definitive clinical trials are described in detail and proposed as the evidence needed for implementation. Several smaller and specific supportive studies are also proposed.

CONCLUSIONS:

The use of ivermectin solves many challenges identified for future vector control strategies. It is an effective and safe endectocide that was approved for human use more than 25 years ago. Recent studies suggest it might become an effective and complementary strategy in malaria elimination and eradication efforts; however, intensive research will be needed to make this a reality.