Excretory/secretory antigen of Toxocara canis: recognition profiles of polyclonal and larvicidal monoclonal antibodies

Summary Five monoclonal antibodies against the excretory/secretory (E/S) antigen of Toxocara canis were obtained and characterized. Immunoprecipitating activity was demonstrated in an in-vitro micropre-cipitating assay using live T. canis larvae. Their capacity to kill larvae was also shown in an in-vitro assay. Two zones of reactivity were observed in 7.5 and 12.5% SDS-PAGE (177-77 kD, 43-15 kD) of immunoprecipitates of human and mouse positive polyclonal anlisera. The murine monoclonal antibodies showed a common pattern of reactivity with the proteins in the 177-77 kD range.     

The surfaces of the parasitic nematodes Trichinella spiralis and Toxocara canis differ in the binding of post-C3 components of human complement by the alternative pathway

The binding of human complement components C3, C5 and C9 to the surface of the infective larvae of the nematode parasites Toxocara canis and Trichinella spiralis, by the alternative pathway, was examined by direct and indirect immunofluorescence on the intact parasites. This showed that although C3 bound to both nematodes, they differed markedly in the binding of C5 and C9; C5 bound only minimally to T. spiralis, and C9 binding to this parasite was barely detectable. In contrast, both early and late components bound to T. canis to a high density, comparable to, or in excess of, the binding of these components to the infective larvae of the trematode Schistosoma mansoni. The lack of binding of the post-C3 components to T. spiralis did not correlate with enhanced binding of the control protein, Factor H.     

Tinea corporis caused by Microsporum canis: Report of a Nosocomial outbreak

In an unusual nosocomial outbreak, 13 staff and 11 patients in an acute and chronic health care facility were infected with the zoophilic dermatophyte, Microsporum canis. The dermatophyte was apparently introduced into the facility by a single infected patient. Likely modes of subsequent disease transmission include person-to-person contact, handling of contaminated laundry, and use of a shared razor. Infection control measures for managing such outbreaks are discussed.     

弓首蛔虫及狮弓蛔虫线粒体基因组nad4基因多态性研究

目的比较犬、猫常见蛔虫的线粒体DNA(mtDNA)中烟酰胺脱氢酶亚基Ⅳ基因(nad4)部分序列(pnad4),以期找出它们之间的序列差异和种群遗传关系。方法抽提61个弓首属蛔虫(包括犬弓首蛔虫、猫弓首蛔虫、马来西亚弓首蛔虫和犊弓首蛔虫)和狮弓蛔虫虫体的总DNA,用PCR方法扩增mtDNApnad4,然后用SSCP技术和DNA测序对序列进行分析研究。结果犬弓首蛔虫种群内pnad4的序列差异为1.17%,与猫弓首蛔虫、马来西亚弓首蛔虫、牛弓首蛔虫和狮弓蛔虫种间的平均序列差异分别为13.92%、16.48%、15.12%和20.32%。猫弓首蛔虫种群内pnad4的序列差异为1.00%,与马来西亚弓首蛔虫、牛弓首蛔虫、狮弓蛔虫平均序列差异分别是17.90%、13.55%和18.50%。马来西亚弓首蛔虫种群内pnad4序列差异为0.13%,与牛弓首蛔虫、狮弓蛔虫序列差异分别为13.50%和20.60%。结论犬弓首蛔虫不同地方虫株的pnad4有一定差异,猫弓首蛔虫种群内差异较小,马来西亚弓首蛔虫种群内差异很小。弓首属各虫种之间的差异以及与狮弓蛔虫的差异都较大。马来西亚弓首蛔虫pnad4序列与其它虫种差异都较大,证明它确为一独立种。pnad4序列是弓首蛔虫和狮弓蛔虫理想的种特异的遗传标记。     

Sequencing and phylogenetic characterization of Brucella canis isolates,Ohio, 2016

Brucella canis is one of zoonotic pathogens causing infection in human. In this study, we isolated and sequenced 38 B. canis strains from 11 cases. Core genome multilocus sequence typing analysis classified all B. canis isolates into two genogroups, GI and GII . All 38 isolates cluster together forming a 2016 Ohio cluster, in which they form five subclusters reflecting their geographical differences. Unlike GI , the isolates of the GII are from diverse geographical locations including Asia, America, Africa, and Europe and form Asia and South America clusters. Overall, our findings could be useful to investigate and track B. canis of future outbreaks.     

Toxocara canis-induced murine pulmonary inflammation: analysis of cells and proteins in lung tissue and bronchoalveolar lavage fluid

The pulmonary immuno-inflammatory reaction and its effect on microvascular integrity was studied in Toxocara canis infected BALB/c mice. The investigation aimed to compare changes in lung histology and composition of bronchoalveolar lavage fluid (BALF) caused by T. canis infection with those described to occur in allergic asthma. Groups of (non)-infected mice (1000 ova) were investigated until 90 days post infection (p.i.). Migration of the larvae through the lungs was followed by a rapidly progressing multifocal interstitial and alveolar inflammation. Eosinophils and lymphocytes formed perivascular and partially peribronchial mixed cellular infiltrates. Lymphocytes with plasma cell morphology staining intracellularly for either α, ɛ or γ immunoglobulins were demonstrated. BALF, collected from mice infected with either 250, 500 or 1000 ova was analysed at 14 and 28 days p.i. A dose-related increase in cell numbers and in albumin and IgA concentration was observed. IgE increase was independent of the infective dose. Peak values were measured at 14 days p.i. Albumin increase in lung homogenate was highest at 28 days p.i. 30% of the lymphocytes consisted of T cells carrying Thy-1.2 and L₃T₄ surface antigens. It is concluded that T. canis-induced pulmonary inflammation affects the permeability of the microvasculature. This is expressed by interstitial oedema and plasma exudation in the airway lumen. Both phenomena occur also in allergic asthma. It is suggested that increased permeability of the microvasculature is mediated by T cells and eosinophils.     

Lafoensia pacari extract inhibits IL-5 production in toxocariasis

Toxocariasis is an infection induced by Toxocara canis, an intestinal parasite of dogs. In this study, an experimental murine model of toxocariasis was used to evaluate the anti-inflammatory activity of an ethanolic extract of Lafoensia pacari stem bark. Mice infected with T. canis were treated with L. pacari extract (200 mg/kg, p.o.). Subsequently, we observed a reduction in the number of eosinophils in the peritoneal cavity, bronchoalveolar fluid, blood and bone marrow. Production of interleukin (IL)-5, a major cytokine involved in eosinophilic differentiation, proliferation and activation, is also an important marker for infection. The reduced levels of IL-5 observed in serum, lung homogenates and bronchoalveolar fluid demonstrated the anti-inflammatory mechanisms of L. pacari. Larvae recovery from infected mice treated with L. pacari was comparable with that from untreated mice, suggesting that L. pacari is not toxic to the parasite. Nonetheless, our results demonstrate a potential therapeutic effect of L. pacari extract in IL-5-mediated inflammatory diseases and provide new prospects for the development of drugs to treat IL-5-dependent allergic diseases such as parasite infection and asthma.     

Influence of maternal infection on offspring immune response in murine larval toxocariasis

The impact of Toxocara canis infection on the proportion of CD4+ and CD8+ T splenocytes, the serum concentrations of cytokine IFN-gamma and IL-5, and the production of Toxocara-specific antibodies were studied in two C57BL6/J mouse groups and their offspring. The mice were infected with 1000 T. canis eggs on the day of mating (early infection) and on day 14 of pregnancy (late infection). Early infection resulted in a significant increase of CD4+ T-cell subtype, however, a decline in CD8+ in comparison with late infection, as well as with non-infected control. The IFN-gamma serum concentrations decreased in infected mothers after the birth when compared with non-infected mothers, while in the offspring this cytokine was barely or not detectable. In the mothers of both infected groups, the humoral immune response included both parasite-specific IgM and IgG2 antibodies. While IgG1 levels remained constant throughout the whole experiment in mothers with early infection, late-infected mothers became seropositive only 3 weeks after delivery. IgM was not detectable in any offspring. Pups from early-infected mothers had IgG1 antibodies. Conversely, IgG2 was detectable in pups of both experimental infection groups. A significant difference was observed in the amounts of pups/litter of the infected mothers in comparison with the non-infected ones. Only 56% of females after early infection and 79% of those after late infection had a successful pregnancy. However, all mice of the control group produced a litter. The first T. canis larvae were detected in the muscles of the offspring of both groups on day 5 after the birth. These data show the changes in regulatory and cytotoxic immunity mechanisms of the infected mothers and their offspring and the high level of pregnancy loss as a result of larval toxocariasis.     

Tinea capitis in children in the district of Cagliari, Italy

Summary. Between 1986 and 1995, 4104 children were observed in the Clinic of Dermatology in Cagliari, Italy. Three hundred and thirty-six children (8.2%), 188 boys and 148 girls, aged 1 month to 13 years, were affected by tinea capitis. Microsporum canis was detected in 278 cases (82.7%) and Trichophyton mentagrophytes in 58 cases (17.3%). Systemic treatment with 20–25 mg kg^-1 day^-1 griseofulvin led to complete recovery in 30–40 days. None of the patients relapsed. The epidemiology of the infection was analysed according to age, sex and seasonal progression. Microsporum canis was the preponderant aetiological agent of tinea capitis in children in the district of Cagliari, Italy.
Zusammenfassung. In den Jahren 1986–1995 sind in der dermatologischen Klinik der Universität Cagliari (Italien) 4104 Kinder untersucht worden, wobei bei 336 (8.2%) im Alter zwischen einem Monat und 13 Jahren (188 männlich und 148 weiblich) eine Tinea capitis diagnostiziert wurde. Unter den isolierten Myzeten wurden in 278 (82.7%) Fällen Microsporum canis und in 58 (17.3%) Fällen Trichophyton mentagrophytes gefunden. Die Basisbehandlung mit Griseofulvin 20–25 mg kg^-1 die^-1 hat bei allen Patienten nach 30–40 Tagen zur vollständigen Heilung geführt. Es traten keine Rezidive auf. Das epidemiologische Profil wurde in Beziehung zum Alter, Geschlecht, und jahreszeitlichem Verlauf analysiert. M. canis war der Erreger in den meisten Fällen von Tinea capitis im Kindesalter in der Provinz Cagliari.     

Incidence of dermatophytoses in rabbit farms in Catalonia,Spain, and its repercussion on human health

Over the past decades there has been an important increase in the incidence of dermatophytoses in humans as a result of contact with animals, although etiological agents can vary as can the animals transmitting the disease. A large-scale study was carried out in 220 farms raising rabbits for consumption. Most of the farms (85%) were located in the autonomous community of Catalonia (Spain). Mycological studies showed that 79.5% of the rabbits were infected with Trichophyton mentagrophytes var. granulosum. Microsporum canis was isolated in only two animals, which had been imported from France. Healthy animal carriers were detected in 3.2% of the apparently non-infected farms. T. mentagrophytes were also found in samples taken from rabbits' nests and from the sorrounding environment of the two infected farms.In a survey carried out among the staff responsible for the care of the animals, 77% of those working on infected farms suffered or had suffered dermatophytic lesions. This was confirmed in 8 out of 10 cases sampled. Attention is drawn to the high incidence of dermatophytoses in rabbits on farms and the importance of T. mentagrophytes as the etiological agent of tineas in people in close contact with infected animals.