Toxocara canis e T. cati são nematódeos parasitos de cães e gatos, transmitidos pela ingestão de ovos larvados, pela via transmamária, por predação de hospedeiro paratênico e via transplacentária; essa última via ocorre na infecção por T. canis. Muitos parasitos apresentam mecanismos para alterar o comportamento de seus hospedeiros e garantir sua transmissão. Vários pesquisadores demonstraram ocorrência de alterações comportamentais, utilizando camundongos como modelo de hospedeiro paratênico para T. canis. Porém, não há na literatura, estudos sobre a ocorrência de alterações de comportamento de Rattus norvegicus experimentalmente infectados por T. cati. Os objetivos do presente trabalho foram verificar a distribuição de larvas de T.cati em exemplares de R. norvegicus e determinar as fases miotrópica e neurotrópica na infecção deste parasito; bem como comparar comportamentos de fêmeas e machos deste roedor experimentalmente infectado com inóculo de T. canis ou T. cati, nos períodos agudo e crônico da infecção. As variáveis avaliadas foram: ansiedade, atividade motora e força muscular. Inicialmente utilizaram-se 21 ratos com idade de oito semanas, infectados com 300 ovos de T. cati. Nos dias 3, 5, 8, 10, 15, 30 e 60 pósinfecção três animais foram mortos para contagem das larvas em seus órgãos. A seguir foram utilizados 50 exemplares fêmeas e 50 machos de R. norvegicus, com seis a oito semanas. Para cada sexo os animais foram divididos em três grupos: T. canis - 20 ratos infectados com 300 ovos de T. canis, T.cati -20 ratos infectados com 300 ovos de T. cati e controle - 10 ratos sem infecção. Nos dias 5, 15, 40 e 70 após a infecção, os animais dos grupos infectados e controle foram submetidos à avaliação das variáveis comportamentais e determinação da força muscular. Pôde-se verificar que a fase neurotrópica das larvas ocorreu principalmente no 15º dpi e 30º dpi. A fase miotrópica ocorreu em todo o período do experimento, porém especialmente no 15º e 60º dpi. Em relação à força muscular das fêmeas, pode-se observar diferença significante nos três grupos apenas no 40º dpi. Nos machos houve diferença significante entre os três grupos durante todo experimento. Nas variáveis comportamentais, somente as fêmeas do grupo infectado com T. canis apresentaram diferença significativa no 40º dpi em relação ao grupo controle. Os machos não apresentaram diferenças significantes na avaliação do comportamento. Pode-se concluir que T. cati teve comportamento migratório diferenciado, exemplares de R. norvegicus independente do sexo apresentaram maior decréscimo na força muscular quando infectados com T. cati e que apenas fêmeas infectadas por T. canis tiveram seu comportamento alterado permanecendo por mais tempo em condições de exposição em campo aberto. / Toxocara canis and T. cati are parasitic nematodes of dogs and cats, transmitted by the ingestion of embryonated eggs, by the transmamary and transplacentary routes or by predation of paratenic hosts harboring third-stage larvae in their bodies. The transplacentary route occurs only in T. canis infection. Many parasites have mechanisms to change the host\'s behavior in order to ensure their transmission. Several researchers have demonstrated the occurrence of behavioral changes, using mice as a model of paratenic host for T. canis. However, there are no studies on the occurrence of changes in behavior of Rattus norvegicus experimentally infected with T. cati. The aims of this study were to investigate the distribution of T.cati larvae in R. norvegicus and determine the myotropic and neurotropic phases in the infection of this parasite, and to compare behavior of male and female rodents experimentally infected with either T. canis or T. cati, in the acute and chronic periods of infection. The variables measured were: anxiety, motor activity and muscle strength. Initially we used 21 rats aged eight weeks, infected with 300 eggs of T. cati. On days 3, 5, 8, 10, 15, 30 and 60 post-infection three animals were killed to count the larvae in the organs and muscle. In the second experiment 50 females and 50 males of R. norvegicus, with six to eight weeks of age were used. For each sex the animals were divided into three groups: T. canis - 20 rats infected with 300 eggs of T. canis, T.cati -20 rats infected with 300 eggs of T. cati and control - 10 rats infection free. On days 5, 15, 40 and 70 post-infection, the infected animals and control groups were submitted to evaluation of behavioral variables and determination of forepaws\' muscle strength. It was verified that the neurotropic phase of larvae occurred mainly in the 15th dpi and 30 dpi. Myotropic phase occurred during all experimental period, but especially 15th and 60th dpi. In regard to muscle strength in females, a significant difference in the three groups was observed only after 40th post-infection. In males there was significant difference among the three groups throughout the experiment. In the behavioral variables, only the female of the group infected with T. canis showed significant differences after 40th dpi when compared to control group. Males showed no significant differences in the performance evaluation. It can be concluded that T. cati migration behavior was different, R. norvegicus regardless of sex showed greater decrease in muscle strength when infected with T. cati and only infected females by T. canis showed behavioral changes remaining more time under conditions of exposure in the open field.

Diss. (sammanfattning) Linköping : Linköpings universitet, 2008. / Härtill 4 uppsatser.

Toxocara canis e T. cati são nematódeos parasitos de cães e gatos, transmitidos pela ingestão de ovos larvados, pela via transmamária, por predação de hospedeiro paratênico e via transplacentária; essa última via ocorre na infecção por T. canis. Muitos parasitos apresentam mecanismos para alterar o comportamento de seus hospedeiros e garantir sua transmissão. Vários pesquisadores demonstraram ocorrência de alterações comportamentais, utilizando camundongos como modelo de hospedeiro paratênico para T. canis. Porém, não há na literatura, estudos sobre a ocorrência de alterações de comportamento de Rattus norvegicus experimentalmente infectados por T. cati. Os objetivos do presente trabalho foram verificar a distribuição de larvas de T.cati em exemplares de R. norvegicus e determinar as fases miotrópica e neurotrópica na infecção deste parasito; bem como comparar comportamentos de fêmeas e machos deste roedor experimentalmente infectado com inóculo de T. canis ou T. cati, nos períodos agudo e crônico da infecção. As variáveis avaliadas foram: ansiedade, atividade motora e força muscular. Inicialmente utilizaram-se 21 ratos com idade de oito semanas, infectados com 300 ovos de T. cati. Nos dias 3, 5, 8, 10, 15, 30 e 60 pósinfecção três animais foram mortos para contagem das larvas em seus órgãos. A seguir foram utilizados 50 exemplares fêmeas e 50 machos de R. norvegicus, com seis a oito semanas. Para cada sexo os animais foram divididos em três grupos: T. canis - 20 ratos infectados com 300 ovos de T. canis, T.cati -20 ratos infectados com 300 ovos de T. cati e controle - 10 ratos sem infecção. Nos dias 5, 15, 40 e 70 após a infecção, os animais dos grupos infectados e controle foram submetidos à avaliação das variáveis comportamentais e determinação da força muscular. Pôde-se verificar que a fase neurotrópica das larvas ocorreu principalmente no 15º dpi e 30º dpi. A fase miotrópica ocorreu em todo o período do experimento, porém especialmente no 15º e 60º dpi. Em relação à força muscular das fêmeas, pode-se observar diferença significante nos três grupos apenas no 40º dpi. Nos machos houve diferença significante entre os três grupos durante todo experimento. Nas variáveis comportamentais, somente as fêmeas do grupo infectado com T. canis apresentaram diferença significativa no 40º dpi em relação ao grupo controle. Os machos não apresentaram diferenças significantes na avaliação do comportamento. Pode-se concluir que T. cati teve comportamento migratório diferenciado, exemplares de R. norvegicus independente do sexo apresentaram maior decréscimo na força muscular quando infectados com T. cati e que apenas fêmeas infectadas por T. canis tiveram seu comportamento alterado permanecendo por mais tempo em condições de exposição em campo aberto. / Toxocara canis and T. cati are parasitic nematodes of dogs and cats, transmitted by the ingestion of embryonated eggs, by the transmamary and transplacentary routes or by predation of paratenic hosts harboring third-stage larvae in their bodies. The transplacentary route occurs only in T. canis infection. Many parasites have mechanisms to change the host\'s behavior in order to ensure their transmission. Several researchers have demonstrated the occurrence of behavioral changes, using mice as a model of paratenic host for T. canis. However, there are no studies on the occurrence of changes in behavior of Rattus norvegicus experimentally infected with T. cati. The aims of this study were to investigate the distribution of T.cati larvae in R. norvegicus and determine the myotropic and neurotropic phases in the infection of this parasite, and to compare behavior of male and female rodents experimentally infected with either T. canis or T. cati, in the acute and chronic periods of infection. The variables measured were: anxiety, motor activity and muscle strength. Initially we used 21 rats aged eight weeks, infected with 300 eggs of T. cati. On days 3, 5, 8, 10, 15, 30 and 60 post-infection three animals were killed to count the larvae in the organs and muscle. In the second experiment 50 females and 50 males of R. norvegicus, with six to eight weeks of age were used. For each sex the animals were divided into three groups: T. canis - 20 rats infected with 300 eggs of T. canis, T.cati -20 rats infected with 300 eggs of T. cati and control - 10 rats infection free. On days 5, 15, 40 and 70 post-infection, the infected animals and control groups were submitted to evaluation of behavioral variables and determination of forepaws\' muscle strength. It was verified that the neurotropic phase of larvae occurred mainly in the 15th dpi and 30 dpi. Myotropic phase occurred during all experimental period, but especially 15th and 60th dpi. In regard to muscle strength in females, a significant difference in the three groups was observed only after 40th post-infection. In males there was significant difference among the three groups throughout the experiment. In the behavioral variables, only the female of the group infected with T. canis showed significant differences after 40th dpi when compared to control group. Males showed no significant differences in the performance evaluation. It can be concluded that T. cati migration behavior was different, R. norvegicus regardless of sex showed greater decrease in muscle strength when infected with T. cati and only infected females by T. canis showed behavioral changes remaining more time under conditions of exposure in the open field.

In children, joint hypermobility (typified by structural instability of joints) manifests clinically as neuro-muscular and musculo-skeletal conditions and conditions associated with development and organization of control of posture and gait (Finkelstein, 1916; Jahss, 1919; Sobel, 1926; Larsson, Mudholkar, Baum and Srivastava, 1995; Murray and Woo, 2001; Hakim and Grahame, 2003; Adib, Davies, Grahame, Woo and Murray, 2005:). The process of control of the relative proportions of joint mobility and stability, whilst maintaining equilibrium in standing posture and gait, is dependent upon the complex interrelationship between skeletal, muscular and neurological function (Massion, 1998; Gurfinkel, Ivanenko, Levik and Babakova, 1995; Shumway-Cook and Woollacott, 1995). The efficiency of this relies upon the integrity of neuro-muscular and musculo-skeletal components (ligaments, muscles, nerves), and the Central Nervous System’s capacity to interpret, process and integrate sensory information from visual, vestibular and proprioceptive sources (Crotts, Thompson, Nahom, Ryan and Newton, 1996; Riemann, Guskiewicz and Shields, 1999; Schmitz and Arnold, 1998) and development and incorporation of this into a representational scheme (postural reference frame) of body orientation with respect to internal and external environments (Gurfinkel et al., 1995; Roll and Roll, 1988). Sensory information from the base of support (feet) makes significant contribution to the development of reference frameworks (Kavounoudias, Roll and Roll, 1998). Problems with the structure and/ or function of any one, or combination of these components or systems, may result in partial loss of equilibrium and, therefore ineffectiveness or significant reduction in the capacity to interact with the environment, which may result in disability and/ or injury (Crotts et al., 1996; Rozzi, Lephart, Sterner and Kuligowski, 1999b). Whilst literature focusing upon clinical associations between joint hypermobility and conditions requiring therapeutic intervention has been abundant (Crego and Ford, 1952; Powell and Cantab, 1983; Dockery, in Jay, 1999; Grahame, 1971; Childs, 1986; Barton, Bird, Lindsay, Newton and Wright, 1995a; Rozzi, et al., 1999b; Kerr, Macmillan, Uttley and Luqmani, 2000; Grahame, 2001), there has been a deficit in controlled studies in which the neuro-muscular and musculo-skeletal characteristics of children with joint hypermobility have been quantified and considered within the context of organization of postural control in standing balance and gait. This was the aim of this project, undertaken as three studies. The major study (Study One) compared the fundamental neuro-muscular and musculo-skeletal characteristics of 15 children with joint hypermobility, and 15 age (8 and 9 years), gender, height and weight matched non-hypermobile controls. Significant differences were identified between previously undiagnosed hypermobile (n=15) and non-hypermobile children (n=15) in passive joint ranges of motion of the lower limbs and lumbar spine, muscle tone of the lower leg and foot, barefoot CoP displacement and in parameters of barefoot gait. Clinically relevant differences were also noted in barefoot single leg balance time. There were no differences between groups in isometric muscle strength in ankle dorsiflexion, knee flexion or extension. The second comparative study investigated foot morphology in non-weight bearing and weight bearing load conditions of the same children with and without joint hypermobility using three dimensional images (plaster casts) of their feet. The preliminary phase of this study evaluated the casting technique against direct measures of foot length, forefoot width, RCSP and forefoot to rearfoot angle. Results indicated accurate representation of elementary foot morphology within the plaster images. The comparative study examined the between and within group differences in measures of foot length and width, and in measures above the support surface (heel inclination angle, forefoot to rearfoot angle, normalized arch height, height of the widest point of the heel) in the two load conditions. Results of measures from plaster images identified that hypermobile children have different barefoot weight bearing foot morphology above the support surface than non-hypermobile children, despite no differences in measures of foot length or width. Based upon the differences in components of control of posture and gait in the hypermobile group, identified in Study One and Study Two, the final study (Study Three), using the same subjects, tested the immediate effect of specifically designed custom-made foot orthoses upon balance and gait of hypermobile children. The design of the orthoses was evaluated against the direct measures and the measures from plaster images of the feet. This ascertained the differences in morphology of the modified casts used to mould the orthoses and the original image of the foot. The orthoses were fitted into standardized running shoes. The effect of the shoe alone was tested upon the non-hypermobile children as the non-therapeutic equivalent condition. Immediate improvement in balance was noted in single leg stance and CoP displacement in the hypermobile group together with significant immediate improvement in the percentage of gait phases and in the percentage of the gait cycle at which maximum plantar flexion of the ankle occurred in gait. The neuro-muscular and musculo-skeletal characteristics of children with joint hypermobility are different from those of non-hypermobile children. The Beighton, Solomon and Soskolne (1973) screening criteria successfully classified joint hypermobility in children. As a result of this study joint hypermobility has been identified as a variable which must be controlled in studies of foot morphology and function in children. The outcomes of this study provide a basis upon which to further explore the association between joint hypermobility and neuro-muscular and musculo-skeletal conditions, and, have relevance for the physical education of children with joint hypermobility, for footwear and orthotic design processes, and, in particular, for clinical identification and treatment of children with joint hypermobility.