Schistosoma japonicum: localization of calpain in the penetration glands and secretions of cercariae

A monoclonal antibody was generated against the large subunit of Schistosoma japonicum calpain to study the localization and possible function of the molecule in vivo. Mice were immunized with recombinant S. japonicum calpain and polyclonal antisera and a monoclonal antibody specific to schistosome calpain was obtained. In immunohistochemistry, a monoclonal antibody against S. japonicum calpain, KG-2E11, bound weakly to calpain expressed at the surface of adult worm tegument, however, it bound strongly to the cercarial secretions ("footprints") of S. japonicum, emitted from the penetration glands. The present study indicates that calpain is multifunctional as it is expressed at various locations in different developmental stages. Calpain-based vaccines could thus possibly induce protective immunity against cercariae and the following early developing stages.     

Spanning the gap: experimental determination of paratenic host specificity of horsehair worms (Nematomorpha: Gordiida)

Abstract. Details of the life cycle of freshwater nematomorphs (gordiids) remain unclear. Free-living aquatic larval gordiids must make a critical transition from an epibenthic aquatic environment to terrestrial hosts. In order to identify potential hosts capable of bridging this ecological gap, the specificity of paratenic hosts of three common species of North American gordiids was investigated. All three species were characterized by an identical infection pattern: low host specificity. Gordiids were able to encyst within annelids, mollusks, crustaceans, insects and a vertebrate. Three species of putative host (a turbellarian, a water mite, and a mosquito larva) were not infected with any of the gordiid species. Internal defense reactions (IDR) and feeding behaviors are implicated as preventing infection in these species. Several of the other host species produced either an IDR or an immune reaction to the cysts, although reactions to the cysts were highly variable between species. In most species, IDR did not cause noticeable harm to the encysted larvae. It is proposed that although many species are easily infected with gordiid cysts, most do not act as natural paratenic hosts. For some of these host groups, especially snails, a role as reservoir host is suggested. Of all hosts included in this study, aquatic insects were identified as the hosts likely responsible for spanning the ecological gap and acting as true hosts for gordiids.     

20世纪初以前西方学者对中国冬虫夏草的记载和研究

冬虫夏草在中国是一种著名的药材。最早记录它的文献是15世纪的藏医籍《千万舍利》。随着法国传教士巴多明(Parennin)于1723年将冬虫夏草标本从北京寄往法兰西科学院,西方学术界开始了对这种中国药材的认识和研究历程。在1841年英国昆虫学家韦斯特伍德(Westwood)开始鉴定这种真菌以前,西方学者认为冬虫夏草的真菌子实体是植物的根。此后,英国真菌学家贝克莱(Berkeley)分别在1843和1856年将其定名为"Sphaeria Sinensis"和"Cordyceps sinensis"。但是为学界广泛使用并沿用至今的,却是意大利植物学家萨卡多(Saccardo)在其1883年的专著中为冬虫夏草的定名"Cordyceps sinensis(Berk.)Sacc."。在20世纪初以前,西方人对中国冬虫夏草的记录和描述具有多重价值,对于了解中国冬虫夏草的使用历史而言是重要的补充资料。     

Alternative transmission pathways for guinea worm in dogs: implications for outbreak risk and control

Guinea worm (Dracunculus medinensis) has exerted a high human health burden in parts of Africa. Complete eradication of Guinea worm disease (dracunculiasis) may be delayed by the circulation of the parasite in domestic dogs. As with humans, dogs acquire the parasite by directly ingesting infected copepods, and recent evidence suggests that consuming frogs that ingested infected copepods as tadpoles may be a viable transmission route (paratenic route). To understand the relative contributions of direct and paratenic transmission routes, we developed a mathematical model that describes transmission of Guinea worm between dogs, copepods and frogs. We explored how the parasite basic reproductive number (R₀) depends on parameters amenable to actionable interventions under three scenarios: frogs/tadpoles do not consume copepods; tadpoles consume copepods but frogs do not contribute to transmission; and frogs are paratenic hosts. We found a non-monotonic relationship between the number of dogs and R₀. Generally, frogs can contribute to disease control by removing infected copepods from the waterbody even when paratenic transmission can occur. However, paratenic transmission could play an important role in maintaining the parasite when direct transmission is reduced by interventions focused on reducing copepod ingestion by dogs. Together, these suggest that the most effective intervention strategies may be those which focus on the reduction of copepods, as this reduces outbreak potential irrespective of the importance of the paratenic route.     

Effects of Winter Ticks and Internal Parasites on Moose Survival in Vermont,USA

Moose (Alces alces) have experienced considerable declines along the periphery of their range in the northeastern United States. In Vermont, the population declined 45% from 2010 to 2017 despite minimal hunter harvest and adequate habitat. Similarly, nearby populations recently experienced epizootics characterized by >50% mortality. Declines have largely been associated with the effects of winter ticks (Dermacentor albipictus), but uncertainty exists about the effects of environmental and other parasite-related conditions on moose survival. We examined patterns of moose survival among a radio-collared population (n = 127) in Vermont from 2017 to 2019. Our objectives were to estimate causes of mortality and model survival probability as a function of individual and landscape variables for calves (<1 yr) and adults (≥1 yr). Observed adult survival was 90% in 2017, 84% in 2018, and 86% in 2019, and winter calf survival was 60% in 2017, 50% in 2018, and 37% in 2019. Winter tick infestation was the primary cause of mortality (91% of calves, 25% of adults), and 32% of all mortalities had evidence of meningeal worm (Parelaphostrongylus tenuis). Other sources of mortality such as vehicles, harvest, predation, deep snow, and other parasitic infections were negligible. The best supported calf model included sex differences and negative effects of tick engorgement (%/week) and parasite level (roundworm and lungworm). The best supported adult model included the effect of cumulative tick engorgement (cumulative %/week), which negatively affected survival. Our results indicate that winter tick engorgement strongly affects survival, and is probably compounded by the presence of meningeal worm and other parasites. Reduced tick effects may be achieved by decreasing moose density through harvest and managing late winter habitat to minimize tick density. Management of white-tailed deer (Odocoileus virginianus) density may also affect the transmission of meningeal worm. © 2021 The Authors. The Journal of Wildlife Management published by Wiley Periodicals LLC on behalf of The Wildlife Society.     

Oviposition dynamics and larval development of Helicoverpa armigera on a highly preferred unsuitable host plant,Solanum viarum

Oogenesis and oviposition dynamics of female moths of tomato fruitworm, Helicoverpa armigera Hübner (Lepidoptera: Noctuidae), were compared in a monoculture of tomato (Solanum lycopersicum L.) and in mixtures with a highly preferred but unsuitable host plant, Solanum viarum Dunal. Female H. armigera provided with S. viarum laid many more eggs than those provided with tomato, both in choice and no‐choice experiments. Gravid female moths did not display any preference for oviposition neither between young or old plants of S. viarum or tomato, nor between young and old leaves of S. viarum. Larval mortality and larval developmental period significantly increased, with subsequent reduction in pupal weight, when H. armigera larvae fed on S. viarum leaves compared to a meridic diet. Oviposition of female moths significantly increased in tomato in the presence of S. viarum volatiles. However, in screen cages with an increasing percentage of S. viarum as a trap crop, the number of eggs laid on tomato as the main crop was the same. The results of this study are discussed in light of the possibility of using S. viarum as a ‘dead‐end’ trap crop.     

Current Status of Taeniasis in Thailand

Taeniasis is prevalent in all regions of Thailand, except the South. Infections were more frequently found in males than females of any age from 7-83 years. Taenia saginata is the most common species throughout the country. Taenia asiatica was reported only in the province of Kanchanaburi in the Central region. Co-infections, with Taenia solium and T. asiatica or T. solium and T. saginata, were found. Hybridization between T. asiatica and T. saginata is evidence that co-infection is never found between these 2 species. Finding more than 1 worm in a single patient was not entirely rare. Genetic variation was found without correlation to its geographic distribution in T. saginata, whereas no variation was found in T. asiatica.     

Effects of copper and other metals on fertilization,embryo development,larval survival and settlement of the polychaete Nereis (Neanthes) virens

Summary

Nectochaete larvae of the ecologically and economically important ragworm, Nereis virens, were exposed to cadmium, chromium, copper, lead and zinc dissolved in seawater to nominal concentrations ranging from 0 to 5000 μg l^?1. Copper was the most toxic (mean LC50 of 76.5 μg l^?1 ± 95% CI 73.8–79.2 after 96 h exposure) and so was used for subsequent experiments. Exposure of gametes to greater than 500 μg l^?1 copper for 2 or 4 h at 10°C prior to fertilization, or a 10 min exposure during fertilization, significantly reduced embryo developmental success. The effect of copper on larval settlement was also assessed using sediment spiked to a range of concentrations (0, 50, 250, 500, 1000 mg kg!1 dry weight). Significantly fewer larvae were found in sediment of $250 mg kg!1 in comparison to the control or the 50 mg kg!1 treatment. Assessment of living larvae also confirmed a significant reduction in settlement, but in all treatments compared to the control, although the number of dead larvae also increased as the concentrations increased. These effects may have important implications for reproductive success and recruitment of N. virens to polluted sediments.     

Effects of initial surface wettability on biofilm formation and subsequent settlement of Hydroides elegans

Hydroides elegans is a major fouling organism in tropical waters around the world, including Pearl Harbor, Hawaii. To determine the importance of initial surface characteristics on biofilm community composition and subsequent colonization by larvae of H. elegans, the settlement and recruitment of larvae to biofilmed surfaces with six different initial surface wettabilities were tested in Pearl Harbor. Biofilm community composition, as determined by a combined approach of denaturing gradient gel electrophoresis and fluorescence in situ hybridization, was similar across all surfaces, regardless of initial wettability, and all surfaces had distinct temporal shifts in community structure over a 10 day period. Larvae settled and recruited in higher numbers to surfaces with medium to low wettability in both May and August, and also to slides with high wettability in August. Pearl Harbor biofilm communities developed similarly on a range of surface wettabilities, and after 10 days in Pearl Harbor all surfaces were equally attractive to larvae of Hydroides elegans, regardless of initial surface properties.     

It’s a wormy world: Meta‐analysis reveals several decades of change in the global abundance of the parasitic nematodes Anisakis spp. and Pseudoterranova spp. in marine fishes and invertebrates

The Anthropocene has brought substantial change to ocean ecosystems, but whether this age will bring more or less marine disease is unknown. In recent years, the accelerating tempo of epizootic and zoonotic disease events has made it seem as if disease is on the rise. Is this apparent increase in disease due to increased observation and sampling effort, or to an actual rise in the abundance of parasites and pathogens? We examined the literature to track long‐term change in the abundance of two parasitic nematode genera with zoonotic potential: Anisakis spp. and Pseudoterranova spp. These anisakid nematodes cause the disease anisakidosis and are transmitted to humans in undercooked and raw marine seafood. A total of 123 papers published between 1967 and 2017 met our criteria for inclusion, from which we extracted 755 host–parasite–location–year combinations. Of these, 69.7% concerned Anisakis spp. and 30.3% focused on Pseudoterranova spp. Meta‐regression revealed an increase in Anisakis spp. abundance (average number of worms/fish) over a 53 year period from 1962 to 2015 and no significant change in Pseudoterranova spp. abundance over a 37 year period from 1978 to 2015. Standardizing changes to the period of 1978–2015, so that results are comparable between genera, we detected a significant 283‐fold increase in Anisakis spp. abundance and no change in the abundance of Pseudoterranova spp. This increase in Anisakis spp. abundance may have implications for human health, marine mammal health, and fisheries profitability.