Clinical status and parasitic infection in a Wichi Aboriginal community in Salta,Argentina

In a study, carried out in 2000, of the clinical and parasitological status of a Wichi Aboriginal community living in the suburbs of Tartagal, northern Salta, Argentina, 154 individuals were screened for parasitic infections. Ninety-five faecal samples were also obtained from the same population. Ninety-three percent of the subjects were positive for 1 or more of the parasites investigated by direct test and 70.5% of them had parasitic superinfection. The most frequent helminths were Strongyloides stercoralis (50.5%) and hookworm (47.4%). We found low reinfection rates and a long reinfection period after treatment and provision of safe water and sanitation. Serum reactivity of these patients was analysed by enzyme-linked immunosorbent assay and indirect immunofluorescent assay and 22.1% of them had anti-Toxocara antibodies, 16.2% were positive for a complex antigen of Leishmania braziliensis, 29.9% were positive for a complex Trypanosoma cruzi antigen, and 17.5% were positive for a specific Trypanosoma cruzi antigen, Ag1 63136/cruzipain.     

广州地区1998～2003年蠕虫感染状况分析

目的 了解和掌握近年广州地区不同职业人群蠕虫分布状况及流行特点，为制订防治策略提供依据。方法 根据本市各区、县级市的地理分布，连续6年分期分批选择不同职业的人群作为调查对象。用清水沉淀法、盐水漂浮法或改良加藤氏厚涂片粪检蠕虫；用透明玻璃胶纸粘贴法检查市区、农村部分幼儿蛲虫。结果 共粪检28376人，感染4315人。感染率15．21％。其中华支睾吸虫感染率6．59％，钩虫感染率4．08％，蛔虫感染率4．78％，鞭虫感染率1．54％。县级市及近郊区感染率较市区高，分别为22．77％和9．92％。职业中以农民感染率最高，为19．68％；环卫工人和饮食服务业次之，感染率分别为8．11％、7．37％。在检查13947人中，男女感染率分别为27．22％和17．95％，感染率随着年龄增长而增高。幼儿蛲虫检查998人，感染79人，感染率7．92％。结论 华支睾吸虫及农村的土源性线虫仍是今后重点防治的寄生虫。采取有效的综合防制措施，加强宣传教育，改变人们不良的饮食习惯，提高个人防护意识，可降低人群蠕虫感染率。     

广东省湛江市农村人群肠道蠕虫感染调查

目的了解湛江市农村人群肠道蠕虫感染现状。方法随机采集村民新鲜粪便，用直接涂片法及饱和盐水浮聚法检查虫卵，用盐酸左旋咪唑驱虫法检查感染钩虫种类。结果粪检190人，虫卵阳性78人，总感染率为41．1％。检出3种肠道蠕虫卵，其中钩虫感染率25．8％，蛔虫感染率12．1％，鞭虫感染率10．5％，有2种或3种虫卵阳性率为6．8％；不同地点各虫感染率不同；钩虫以50—70岁人群感染率较高，蛔虫、鞭虫以20岁以下人群常见；女性的钩虫感染率明显高于男性。药物驱虫后检获有十二指肠钩虫成虫、美洲钩虫成虫及雄性蛔虫，其中，十二指肠钩虫占钩虫比例87．4％，美洲钩虫占钩虫比例12．6％。结论湛江市农村人群感染蛔虫、鞭虫及钩虫常见，其中以钩虫感染最为严重。钩虫感染率较高与旱作生产生活方式密切相关。十二指肠钩虫在该地钩虫流行中占了重要地位。     

IL-10 regulates early IL-12-mediated immune responses induced by the radiation-attenuated schistosome vaccine

Radiation-attenuated (RA) schistosomes penetrate the host via the skin where they stimulate intense inflammatory reactions and the release of pro-inflammatory IL-12, important for T(h)1-type immune responses which are partially host protective. However, RA larvae also induce the secretion of regulatory IL-10. We now show that following vaccination of IL-12p40(-/-) mice, abundant IL-10 was produced by in vitro cultured skin biopsies between days 4 and 14, corresponding to the down-regulation of MHC II expression by cells in the dermis and cells that emigrate from the skin. In IL-10(-/-) mice, inflammation of the vaccination site was increased with larger numbers of IL-12p40(+), MHC II(+) and CD86(+) cells in the dermal exudate, and was associated with elevated levels of skin-derived IL-12p40 and IL-1beta. These changes in IL-10(-/-) mice were also reflected by an increased number of cells in the skin-draining lymph nodes (sdLN) and greater levels of lymphocyte proliferation. Moreover, such mice had increased numbers of CD4(+) sdLN cells that were CD25(+), CD28(+) or CD152(+) and accessory cells that were CD40(+) or MHC II(+). Finally, the secretion of IFN-gamma (and IL-12p40) by in vitro cultured sdLN cells was substantially raised in IL-10(-/-) mice, but much reduced in IL-12p40(-/-) mice, resulting in the development of highly polarized T(h)1 and T(h)2 cytokine profiles in the two groups of mice respectively. We conclude that IL-10 has an important role early in the regulation of IL-12-mediated priming of acquired immune responses, and effectively contains excessive dermal inflammation and prevents the development of highly polarized T(h)1-type responses.     

Interleukin-3-dependent potentiation of IgE responsiveness in mouse basophils

Basophils produce interleukins (IL)-4 in response to various stimuli and may contribute to type 2 immune responses to various infections and allergens. We found that resting basophils freshly isolated from mice produce IL-4 in response to IL-3 but not to high-affinity Fc receptor (FcεRI) cross-linking (CL), yet both required the immunoreceptor tyrosine-based activation motif (ITAM) containing adaptor Fc receptor γ-chain (FcRγ), while basophils activated in vitro by IL-3 become responsive to FcεRI CL. Acquisition of responsiveness to FcεRI CL occurred upon infection with Trichinella spiralis or administration of superantigen. Because cultured basophils return to a quiescent state upon starvation with IL-3 with surface FcεRI levels unchanged, this acquisition is reversible and probably reflects intracellular events requiring protein synthesis. Interestingly, similar activation-associated acquisition was observed for responsiveness to other stimuli, including CD200R3 CL, which is known to signal via DAP-12, and the allergen protease papain. This acquisition of responsiveness to FcεRI CL was inhibited by Jak inhibitor. Thus, the IL-3 signal bifurcates downstream of Jak, into two distinct pathway, one leading to IL-4 production and the other to render basophils competent to respond to stimuli dependent on ITAM-containing adaptors DAP12 and FcRγ for IL-4 production.     

Review of Parasitic Zoonoses in Egypt

This review presents a comprehensive picture of the zoonotic parasitic diseases in Egypt, with particular reference to their relative prevalence among humans, animal reservoirs of infection, and sources of human infection. A review of the available literature indicates that many parasitic zoonoses are endemic in Egypt. Intestinal infections of parasitic zoonoses are widespread and are the leading cause of diarrhea, particularly among children and residents of rural areas. Some parasitic zoonoses are confined to specific geographic areas in Egypt, such as cutaneous leishmaniasis and zoonotic babesiosis in the Sinai. Other areas have a past history of a certain parasitic zoonoses, such as visceral leishmaniasis in the El-Agamy area in Alexandria. As a result of the implementation of control programs, a marked decrease in the prevalence of other zoonoses, such as schistosomiasis and fascioliasis has been observed. Animal reservoirs of parasitic zoonoses have been identified in Egypt, especially in rodents, stray dogs and cats, as well as vectors, typically mosquitoes and ticks, which constitute potential risks for disease transmission. Prevention and control programs against sources and reservoirs of zoonoses should be planned by public health and veterinary officers based on reliable information from systematic surveillance.     

Immunity to gastrointestinal nematodes: a story of immune modulation

Infections with gastrointestinal nematodes are some of the most prevalent infections in the world today. Despite the fact that antihelminthic drugs are generally regarded as safe, efficient and are widely available, the level of infection remains as high or, in some cases, even higher than 50 years ago. It is clear that immune-mediated resistance to infection in mouse models is mediated by a T-helper 2-type immune response. Gastrointestinal nematodes are powerful modulators of the immune response, and as such, they may have the potential to affect the outcome of concurrent infections with other parasites, bacteria or viruses. Importantly, they also appear to have the ability to influence the development of allergic reactions and modulate the effects of vaccination.     

Chronic infections with viruses or parasites: breaking bad to make good

Eukaryotic forms of life have been continually invaded by microbes and larger multicellular parasites, such as helminths. Over a billion years ago bacterial endosymbionts permanently colonized eukaryotic cells leading to recognized organelles with a distinct genetic lineage, such as mitochondria and chloroplasts. Colonization of our skin and mucosal surfaces with bacterial commensals is now known to be important for host health. However, the contribution of chronic virus and parasitic infections to immune homeostasis is being increasingly questioned. Persistent infection does not necessarily equate to exhibiting a chronic illness: healthy hosts (e.g. humans) have chronic viral and parasitic infections with no evidence of disease. Indeed, there are now examples of complex interactions between these microbes and hosts that seem to confer an advantage to the host at a particular time, suggesting that the relationship has progressed along an axis from parasitic to commensal to one of a mutualistic symbiosis. This concept is explored using examples from viruses and parasites, considering how the relationships may be not only detrimental but also beneficial to the human host.     

四川省部分地区肠道蠕虫感染现状调查

目的了解近10年来我省部份地区的肠道蠕虫感染现状。方法采用改良加藤厚涂片法检查肠道蠕虫卵，试管滤纸培养法鉴别钩虫虫种，对12岁以下儿童用透明胶纸肛拭法检查蛲虫卵。结果查出肠道蠕虫7种（线虫4种、吸种2种及带绦虫1种）。总感染率为41．34％。蛔虫、钩虫、鞭虫、蛲虫、带绦虫感染率分别为32．60％、17。30％、13．68％、17．55％、0．86％。部份地区感染率以四川盆地南部边缘的合江县为高，总感染率为77．91％，蛔虫47．90％、钩虫43．51％、鞭虫41．65％、蛲虫44．58％；以川西高原的德格县和位于盆地北部边缘的青川县较低。结论10年来部份地区蛔虫、钩虫、鞭虫及带绦虫感染率均有下降趋势，儿童蛲虫感染率有所回升。调查显示，我省肠道蠕虫感染仍十分严重，应积极普及健康教育，采用综合性防治措施，控制肠道蠕虫感染。