In the middle of the era of molecular biology, much less attention is paid to in vivo phenomena. However, carefully designed experimental systems in vivo still can provide valuable information as to the mechanisms underlying the establishment and maintenance of host-parasite relationships. In this review we describe the advantage of using concurrent infections with appropriately chosen combinations of different genera or different maturation stages of parasites to segregate the cellular responses of the host. By means of simple experimental approaches we have found that mucosal mast cells and goblet cells, both of which have long been considered as non-specific effectors, are in fact highly selective and specific effector cells of the host defence mechanisms capable of acting on the establishment and the expulsion of intestinal helminths.

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This paper reviews the occurrence and impact of threadworms, Strongyloides spp., in companion animals and large livestock, the potential zoonotic implications and future research. Strongyloides spp. infect a range of domestic animal species worldwide and clinical disease is most often encountered in young animals. Dogs are infected with Strongyloides stercoralis while cats are infected with different species according to geographical location (Strongyloides felis, Strongyloides tumefaciens, Strongyloides planiceps and perhaps S. stercoralis). In contrast to the other species, lactogenic transmission is not a primary means of infection in dogs, and S. stercoralis is the only species considered zoonotic. Strongyloides papillosus in calves has been linked to heavy fatalities under conditions of high stocking density. Strongyloides westeri and Strongyloides ransomi of horses and pigs, respectively, cause only sporadic clinical disease. In conclusion, these infections are generally of low relative importance in livestock and equines, most likely due to extensive use of macrocyclic lactone anthelmintics and/or improved hygiene. Future prevalence studies need to include molecular typing of Strongyloides species in relation to different hosts. More research is urgently needed on the potential zoonotic capacity of Strongyloides from dogs and cats based on molecular typing, information on risk factors and mapping of transmission routes.

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The perinatal transmission of bovine leukaemia virus (BLV) plays a critical role in the spread and persistence of BLV infection in cattle herds. The purpose of this study was to examine the frequency of perinatal infections in an area in Japan and investigate some risk factors associated with infection. Altogether, 129 calves born to BLV-infected cows in a herd in Japan were tested for infection immediately after birth and again at one month of age using nested PCR. Twenty-four calves (18.6 per cent) were infected with BLV, of which 14 (10.8 per cent) and 10 (7.7 per cent) calves were infected via the transplacental and the birth canal routes, respectively. Maternal viral loads, breed, the presence or absence of assistance during parturition and the number of births per dam were evaluated to investigate risk factors associated with infection. Maternal viral load was significantly correlated with the frequency of perinatal infection, and more than 40 per cent of newborn calves born to dams with high viral loads were infected with BLV. The results of this study could contribute towards developing effective eradication programmes by providing necessary data for replacement of breeding cow in the field.

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Objective Paragonimiasis, or lung fluke infection, is a food-borne parasitic disease caused by infection with trematodes belonging to the genus Paragonimus. Although paragonimiasis was once considered successfully controlled in the 1970s, new cases began to emerge in the late 1980s. To apprehend the current-day situation of the re-emergent cases of paragonimiasis in Japan, we conducted a retrospective review of 443 patients who were referred to our laboratory and diagnosed as having paragonimiasis during 2001-2012. Methods Patients were diagnosed as having paragonimiasis based primarily on immunodiagnostic methods in addition to clinical, laboratory, and radiographic findings. Patient data were extracted from consultation sheets from attending physicians and were analyzed. Results Majority of the patients were residents of Kyushu Island. However, a substantial number of cases were also from other parts of Japan. Immigrants (mostly from China, Thailand, and Korea) accounted for a quarter of the cases. Native Japanese contracted paragonimiasis by consuming wild boar meat or freshwater crabs, whereas immigrants contracted the infection almost exclusively by consumption of freshwater crabs. Eosinophilia and elevated serum IgE levels were found in around 80% of the patients. Parasite egg detection was documented only in 11.7% of the cases, showing the reliance on serological tests for diagnosing paragonimiasis in current clinical practice. Conclusion Paragonimiasis remains a public health issue in Japan, and the situation should be closely monitored.

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