Adoptive Transfer of Immune Cells Into RAG2IL-2Rγ-Deficient Mice During Litomosoides sigmodontis Infection: A Novel Approach to Investigate Filarial-Specific Immune Responses.

Despite long-term mass drug administration programmes, approximately 220 million people are still infected with filariae in endemic regions. Several research studies have characterized host immune responses but a major obstacle for research on human filariae has been the inability to obtain adult worms which in turn has hindered analysis on infection kinetics and immune signalling. Although the Litomosoides sigmodontis filarial mouse model is well-established, the complex immunological mechanisms associated with filarial control and disease progression remain unclear and translation to human infections is difficult, especially since human filarial infections in rodents are limited. To overcome these obstacles, we performed adoptive immune cell transfer experiments into RAG2IL-2Rγ-deficient C57BL/6 mice. These mice lack T, B and natural killer cells and are susceptible to infection with the human filaria Loa loa. In this study, we revealed a long-term release of L. sigmodontis offspring (microfilariae) in RAG2IL-2Rγ-deficient C57BL/6 mice, which contrasts to C57BL/6 mice which normally eliminate the parasites before patency. We further showed that CD4+ T cells isolated from acute L. sigmodontis-infected C57BL/6 donor mice or mice that already cleared the infection were able to eliminate the parasite and prevent inflammation at the site of infection. In addition, the clearance of the parasites was associated with Th17 polarization of the CD4+ T cells. Consequently, adoptive transfer of immune cell subsets into RAG2IL-2Rγ-deficient C57BL/6 mice will provide an optimal platform to decipher characteristics of distinct immune cells that are crucial for the immunity against rodent and human filarial infections and moreover, might be useful for preclinical research, especially about the efficacy of macrofilaricidal drugs.

Genome editing as control tool for filarial infections.

Human filarial infections are vector-borne nematode infections, which include lymphatic filariasis, onchocerciasis, loiasis, and mansonella filariasis. With a high prevalence in developing countries, filarial infections are responsible for some of the most debilitating morbidities and a vicious cycle of poverty and disease. Global initiatives set to eradicate these infections include community mass treatments, vector control, provision of care for morbidity, and search for vaccines. However, there are growing challenges associated with mass treatments, vector control, and antifilarial vaccine development. With the emergence of genome editing tools and successful applications in other infectious diseases, the integration of genetic editing techniques in future control strategies for filarial infections would offer the best option for eliminating filarial infections. In this review, we briefly discuss the mechanisms of the three main genetic editing techniques and explore the potential applications of these powerful tools to control filarial infections.

A Combination of Deworming and Prime-Boost Vaccination Regimen Restores Efficacy of Vaccination Against Influenza in Helminth-Infected Mice.

Helminths still infect a quarter of the human population. They manage to establish chronic infections by downmodulating the immune system of their hosts. Consequently, the immune response of helminth-infected individuals to vaccinations may be impaired as well. Here we study the impact of helminth-induced immunomodulation on vaccination efficacy in the mouse system. We have previously shown that an underlying Litomosoides sigmodontis infection reduced the antibody (Ab) response to anti-influenza vaccination in the context of a systemic expansion of type 1 regulatory T cells (Tr1). Most important, vaccine-induced protection from a challenge infection with the 2009 pandemic H1N1 influenza A virus (2009 pH1N1) was impaired in vaccinated, L. sigmodontis-infected mice. Here, we aim at the restoration of vaccination efficacy by drug-induced deworming. Treatment of mice with Flubendazole (FBZ) resulted in elimination of viable L. sigmodontis parasites in the thoracic cavity after two weeks. Simultaneous FBZ-treatment and vaccination did not restore Ab responses or protection in L. sigmodontis-infected mice. Likewise, FBZ-treatment two weeks prior to vaccination did not significantly elevate the influenza-specific Ig response and did not protect mice from a challenge infection with 2009 pH1N1. Analysis of the regulatory T cell compartment revealed that L. sigmodontis-infected and FBZ-treated mice still displayed expanded Tr1 cell populations that may contribute to the sustained suppression of vaccination responses in successfully dewormed mice. To outcompete this sustained immunomodulation in formerly helminth-infected mice, we finally combined the drug-induced deworming with an improved vaccination regimen. Two injections with the non-adjuvanted anti-influenza vaccine Begripal conferred 60% protection while MF59-adjuvanted Fluad conferred 100% protection from a 2009 pH1N1 infection in FBZ-treated, formerly L. sigmodontis-infected mice. Of note, applying this improved prime-boost regimen did not restore protection in untreated L. sigmodontis-infected mice. In summary our findings highlight the risk of failed vaccinations due to helminth infection.

Filarial hydropneumothorax: a strange journey.

Filarial infection can have varied manifestations, but hydropneumothorax at presentation has not yet been reported. A 28-year-old man presented to our hospital with heaviness of the left chest for the past 10 days, which was preceded by a sudden, short stabbing pain in the left chest after straining. Chest X-ray revealed left-sided hydropneumothorax. A peripheral blood picture revealed significant eosinophilia. A pleural fluid report also showed eosinophilia and a few motile microfilaria of Wuchereria bancrofti. Microfilaria was also documented in peripheral blood. There was no evidence of other organ system involvement. The patient was diagnosed with 'Filarial Hydropneumothorax'. After treatment with a temporary chest drain and oral diethylcarbamazine citrate, there was dramatic relief of symptoms and radiological improvement. The patient has been symptom free with no features of recurrence through 8 months of follow-up.

Neurological manifestations of filarial infections.

Filarial infections cause a huge public health burden wherever they are endemic. These filaria may locate anywhere in the human body. Their manifestations and pathogenic mechanisms, except the most common ones, are rarely investigated systematically. Their neurological manifestations, however, are being increasingly recognized particularly with onchocerciasis or Loa loa infections, Wuchereria bancrofti, or Mansonella perstans. The risk of developing these manifestations may also increase in cases that harbor multiple filariasis or coinfections, for instance as with Plasmodium. The microfilaria of Onchocerca and Loa loa are seen in cerebrospinal fluid. The pathogenesis of neurological manifestations of these infections is complex; however, pathogenic reactions may be caused by mechanical disruption, e.g., degeneration often followed by granulomas, causing fibrosis or mass effects on other tissues, vascular lesions, e.g., vascular block of cerebral vessels, or disordered inflammatory responses resulting in meningitis, encephalitis or localized inflammatory responses. The chances of having neurological manifestations may also depend upon the frequency and"heaviness"of infection over a lifetime. Hence, this type of infection should no longer be considered a disease of the commonly affected areas but one that may produce systemic effects or other manifestations, and these should be considered in populations where they are endemic.

[Follow-up of chronic filariasis patients in Jinshan District, Shanghai from 2009 to 2011].

OBJECTIVE: To understand the prognosis of chronic filariasis patients who were nursed with the care methods recommended by WHO in Jinshan District, Shanghai. METHODS: The chronic filariasis patients who were nursed with the care methods recommended by WHO were followed up in Jinshan District from 2009 to 2011. The patients of Level 1 were followed up once a year; the patients of Level 2 and Level 3 were followed up twice a year. All the results were recorded into the standard questionnaires and analyzed statistically. RESULTS: By the end of 2011, there were 264 chronic filariasis patients, including 106 males and 158 females. There were 201 patients aged between 70 and 85 years old, accounting for 76.14% of the patients. Lymphedema was the most common symptom in the patients and 76.51% of the patients had it. From 2009 to 2011, the conducting rates of sanitary cleaning the limbs, elevation of the limbs, and exercises were 89.02%, 83.71% and 72.08%, respectively. The improvement rates were 6.54%, 10.95% and 14.77% each year, which had a statistically significant difference (chi2 = 18.359, P < 0.01). CONCLUSION: The care methods of chronic filariasis patients recommend by WHO really benefit the relief of lymphedema, and should be popularized.

Nematode infections: filariases.

More than 150 million people, mainly in developing countries, are affected by filarial nematode infections that cause debilitating and disfiguring diseases. Although transmission is restricted to the tropics and subtropics, imported infections sometimes occur in Europe and North America among immigrants and refugees from endemic countries, and rarely among long-term travelers. This article reviews the epidemiology of the most important human filarial nematodes, their current distribution, life cycles, clinical features, and disease burden. Diagnosis, treatment, and tools for prevention and control are discussed. Protective measures for travelers are summarized, and vulnerable groups and case numbers in North America identified.

Human ocular filariasis: further evidence on the zoonotic role of Onchocerca lupi.

BACKGROUND: Among ocular vector-borne pathogens, Onchocerca volvulus, the agent of the so-called "river blindness", affects about 37 million people globally. Other Onchocerca spp. have been sporadically reported as zoonotic agents. Cases of canine onchocerciasis caused by Onchocerca lupi are on the rise in the United States and Europe. Its zoonotic role has been suspected but only recently ascertained in a single case from Turkey. The present study provides further evidence on the occurrence of O. lupi infesting human eyes in two patients from Turkey (case 1) and Tunisia (case 2). The importance of obtaining a correct sample collection and preparation of nematodes infesting human eyes is highlighted. METHODS: In both cases the parasites were identified with morpho-anatomical characters at the gross examination, histological analysis and anatomical description and also molecularly in case 1. RESULTS: The nematode from the first case was obviously O. lupi based on their morphology at the gross examination, histological analysis and anatomical description. In the second case, although the diagnostic cuticular characters were not completely developed, other features were congruent with the identification of O. lupi. Furthermore, the morphological identification was also molecularly confirmed in the Turkish case. CONCLUSIONS: The results of this study suggest that O. lupi infestation is not an occasional finding but it should be considered in the differential diagnosis of other zoonotic helminths causing eye infestation in humans (e.g., D. immitis and Dirofilaria repens). Both cases came from areas where no cases of canine onchocerciasis were previously reported in the literature, suggesting that an in depth appraisal of the infestation in canine populations is necessary. Physicians and ophthalmologists are advised on how to preserve nematode samples recovered surgically, to allow a definitive, correct etiological diagnosis.

Lymphangiosarcoma arising after 33 years within a background of chronic filariasis: a case report with review of literature.

Cutaneous angiosarcoma or lymphangiosarcoma represents an uncommon aggressive tumor known to arise on a background of chronic lymphedema secondary to various etiologies, principally following surgery or irradiation. There have been rarely reported cases of angiosarcoma following infective conditions that eventuate with lymphatic stasis. We report a case of angiosarcoma arising after 33 years within a background of filariasis. Awareness of this association can lead to early diagnosis and appropriate treatment of this potentially fatal malignant tumor.

A review of neglected tropical diseases: filariasis.

Filariasis is result of parasitic infection caused by three specific kinds of round worm. Lymphatic filariasis is found in under developed region of South America, Central Africa, pacific and Caribbian. It has been found for centuries, with main symptoms as elephant like swelling of the arms, legs and genitals. It is estimate that 120 millions peoples in the world have lymphatic filariasis. The spread of diseases and the challenge encountered in its management are discussed along with a review on drugs against filariasis in this article. Detail on clinical effect of drugs on the infection, safety profile, status in clinical practices and drug resistances are also covered.

Th2 responses to helminth parasites can be therapeutically enhanced by, but are not dependent upon, GITR-GITR ligand costimulation in vivo.

The immune suppression that characterizes human helminth infections can hinder the development of protective immunity or help to reduce pathogenic inflammation. Signaling through the T cell costimulator glucocorticoid-induced TNFR-related protein (GITR) counteracts immune downregulation by augmenting effector T cell responses and abrogating suppression by Foxp3(+) regulatory T cells. Thus, superphysiological Ab-mediated GITR costimulation represents a novel therapy for promoting protective immunity toward parasitic helminths, whereas blocking physiological GITR-GITR ligand (GITRL) interactions may provide a mechanism for dampening pathogenic Th2 inflammation. We investigated the superphysiological and physiological roles of the GITR-GITRL pathway in the development of protective and pathogenic Th2 responses in murine infection models of filariasis (Litomosoides sigmodontis) and schistosomiasis (Schistosoma mansoni). Providing superphysiological GITR costimulation using an agonistic anti-GITR mAb over the first 12 d of L. sigmodontis infection initially increased the quantity of Th2 cells, as well as their ability to produce Th2 cytokines. However, as infection progressed, the Th2 responses reverted to normal infection levels, and parasite killing remained unaffected. Despite the Th2-promoting role of superphysiological GITR costimulation, Ab-mediated blockade of the GITR-GITRL pathway did not affect Th2 cell priming or maintenance during L. sigmodontis infection. Blockade of GITR-GITRL interactions during the acute egg phase of S. mansoni infection resulted in reduced Th2 responses, but this effect was confined to the spleen and did not lead to changes in liver pathology. Thus, although superphysiological GITR costimulation can therapeutically enhance Th2 responses, physiological GITR-GITRL interactions are not required for the development of Th2-mediated resistance or pathology in murine models of filariasis and schistosomiasis.

Diversidade genética de Wolbachia Pipientis em populações de culicídeos vetores e no parasito Wuchereria Bancrofti / Genetic diversity of Wolbachia pipientis in populations of vector mosquitoes and the parasite Wuchereria bancrofti

A bactéria endossimbionte Wolbachia tem sido sugerida como mecanismo de controle de insetos vetores e alvo para o tratamento das filarioses. Nesse contexto, estudos sobre a prevalência de Wolbachia em populações de vetores de campo, a análise da sua densidade em insetos sob diferentes condições fisiológicas e a investigação da diversidade genética da bactéria dentro e entre diferentes populações de vetores e em pacientes filarêmicos são relevantes. O presente estudo teve como objetivos: determinar o percentual de infecção em Culex quinquefasciatus e Aedes albopictus coletados em diferentes áreas da RMR - PE - BR; descrever a diversidade dos genes ftsZ e wsp nas linhagens de Wolbachia encontradas tanto nos vetores citados quanto nos vermes filariais coletados de pacientes microfilarêmicos da região; como também comparar a densidade da bactéria em duas populações de C. quinquefasciatus do estado de PE, uma susceptível e outra resistente a temefós. Nossos resultados mostraram que o simbionte Wolbachia está presente em 100 por cento dos vetores analisados quando diagnosticados pelo método de PCR seminested, o qual se mostrou mais eficiente que a PCR convencional. Quanto à densidade do endossimbionte, as fêmeas de C. quinquefasciatus resistentes a organofosforados de Santa Cruz do Capibaribe, Sertão - PE, apresentaram a densidade média, cerca de sete vezes maior que às fêmeas susceptíveis de Peixinhos, RMR - PE, confirmando dados encontrados na literatura. Isto sugere que mosquitos resistentes apresentam maior dificuldade para controlar a densidade do endossimbionte provavelmente pelo custo biológico associado à resistência. Em relação à diversidade genética, os dois genes estudados não mostraram nenhuma variação nas populações observadas. A análise de outros marcadores pode ajudar a esclarecer a relação entre hospedeiros e endossimbionte dando maior suporte ao uso de Wolbachia no desenvolvimento de novas estratégias de controle e tratamento de doenças transmitidas por vetores.

Critical role for IgM in host protection in experimental filarial infection.

We have previously shown that B cells (in particular B1 cells) are important in host protection against brugian infections in a murine i.p. model. In this study, we show that mice deficient in circulating IgM (secIgM-/-), but otherwise normal in their humoral responses, manifest a significant impairment in worm elimination, suggesting that one critical B cell function is the production of Ag-specific IgM. Efficient elimination of larvae is IgM dependent for both primary and challenge infections. The ability to eliminate worms is restored in secIgM-/- mice by administering sera from primed mice. We corroborated these in vivo studies with in vitro observations which show that IgM is the only isotype that reacts strongly with the surface of Brugia L3. Furthermore, activated peritoneal exudate cells adhere to L3 only in the presence of filaria-specific sera or IgM purified from them. This attachment is not reduced by heat inactivation of the serum, suggesting complement independent activity. Peritoneal exudate cells from primed mice, especially activated macrophages, carry high levels of IgM on their surfaces. Our observations suggest that an IgM-mediated reaction initiates the formation of host-protective granulomas.

Filarial chyluria: long-term experience of a university hospital in India.

BACKGROUND: Filariasis is an endemic problem in various Indian states. We evaluated the results of long-term follow up (10-20 years) of patients with filarial chyluria. METHODS: We conducted a retrospective analysis of 160 patients treated for filarial chyluria who presented to the Banaras Hindu University Hospital from 1982 to 1992. Eighty-four patients (52.5%) were treated using diethylcarbamazine (DEC) and a fat restricted diet and 76 patients (47.5%) underwent surgery. To examine the long-term effects of filarial chyluria we analysed data on post-treatment recurrence, weight gain, dietary freedom, chyluria free period and a number of other associated factors. RESULTS: Previous history of filariasis or its complication was documented in 19% of patients. In 71% of cases, cystoscopy showed that chylous efflux was predominant in the left ureteric orifice. The long-term remission rate was 62% in the conservatively managed group (DEC + fat restricted diet), whereas 90% of patients in the operated group were cured. Postoperative recurrence rate was 10%. There was more weight gain and dietary freedom along with a longer chyluria free period in the operated group relative to the conservatively managed group. CONCLUSIONS: Definitive surgical ablation of lymphatic urinary fistula is better than conservative medical management because it has a higher success rate, more dietary freedom and, therefore, better patient acceptability.