Helminth

Helminth parasites are the cause of very significant morbidity, mortality and economic losses in man and domestic animals. Most parasitic helminths infect their hosts via the oral route, and live either at the mucosal surface of the gastro-intestinal tract (GIT), or cross this mucosal barrier on their way to predilection sites. Many helminths live at mucosal surfaces, typically the gut

The past year has brought great progress in the genome-sequencing efforts on a large number of protozoan and metazoan parasites. Whereas many of these projects are in their initial stages, at least one (for Plasmodium falciparum) is nearing completion. The information released to date has been most revealing with respect to immune evasion mechanisms.

Schistosomiasis, caused by blood flukes of the genus Schistosoma, still imposes a considerable public health burden on large parts of the world. The control of this disease depends almost exclusively on the drug praziquantel, and there are no alternative drugs in sight. Natural compounds have recently attracted significant attention due to their relevance to parasitic infection and potential development into new therapeutic agents. Epiisopiloturine is an imidazole alkaloid isolated from the leaves of Pilocarpus microphyllus (Rutaceae), a native plant from Brazil. Here, we report the in vitro effect of this drug on the survival time of Schistosoma mansoni of different ages, such as 3 h old and 1, 3, 5, and 7 days old schistosomula, 49-day-old adults, and on egg output by adult worms. Epiisopiloturine at a concentration of 300 μg/mL caused the death of all schistosomula within 120 h. Extensive tegumental alterations and death were observed when adult schistosomes had been exposed to 150 μg/mL of the epiisopiloturine. At the highest sub-lethal dose of alkaloid (100 μg/mL), a 100% reduction in egg laying of paired adult worms was observed. Additionally, epiisopiloturine showed selective antischistosomal activity and exhibited no cytotoxicity to mammalian cells. This report provides the first evidence that epiisopiloturine is able to kill S. mansoni of different ages and inhibit worm egg laying.

Karrow, N. A., Goliboski, K., Stonos, N., Schenkel, F. and Peregrine, A. 2014. Review: Genetics of helminth resistance in sheep. Can. J. Anim. Sci. 94: 1–9. Gastrointestinal helminth parasites are an important source of economic loss to sheep producers. A rapid increase in anthelmintic resistance has occurred around the globe; therefore, the industry is exploring alternative strategies such as genetic selection to control losses attributed to helminth infection. Since helminths have co-evolved with sheep for millions of years, natural selection for enhanced helminth resistance has occurred within certain breeds from various parts of the world. These breeds of sheep are being used to better understand the genetic aspects of helminth resistance. If the genetic variants that contribute to this phenotype can be identified, it may be possible to use selection strategies to introduce resistance alleles into other breeds or to increase their frequency within breeds. This review will provid...

Chapter 4 Acetate formation in the energy metabolism of parasites KWA van Grinsven a, JJ van Hellemond a, b, AGM Tielensa, b,* a) Department of Biochemistry and Cell Biology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands b) Department of ...

Introduction: There is not much data on parasitic infections of laboratory animals that are kept in conventional conditions in Iran. The present study was designed to investigate intestinal helminths infections in laboratory colonies of rats and mice. Methods: Droppings from 110 mice and 110 rats (each animal one dropping) belonging to experimental and breeding groups in four animal houses were collected. Experimental groups were being used in biomedical researches and breeding groups were not under any experiment. The droppings were preserved in formaldehyde 10% individually and examined by microscopy with 10x magnification. Results: Out of 220 droppings examined, 96 (43.6%) harbored helminths eggs; 53 (48.1%) belonged to mice and 43 (39.09%) to rats. Four helminthes species including, Syphacia obvelata, Syphasia muris, Hymenolepis nana, and Hetrakis spumosa were identified in the both animals, while Aspicularis tetraptera was merely seen in mice. H. nana was the most frequent helminth infection in mice and rats and infection with H. spumosa and A. tetraptera, showed the lowest rates in droppings of mice and rats, respectively. Mixed infections with ≥ two species was observed in 21 (9.5%) of 220 droppings, 14 (12.7%) belonged to mice and 7 (6.3%) to rats. Conclusion: The present results emphasizes more careful monitoring in laboratory animal houses, such as improving the cleaning and ventilating systems as well as adopting therapeutic measures, when required.

Pritchardia boliviensis n. gen. n. sp. (Anoplocephalidae: Linstowiinae) is described from marsupials (Marmosops noctivagus, Metachirus nudicaudatus, Gracilinanus sp.) collected in Bolivia and Paraguay. These cestodes have a very small strobila with only three segments, regularly alternating genital pores, genital ducts crossing excretory canals ventrally, ovoid to pyriform cirrus sac, three to five testes, external seminal vesicle present and separated from cirrus sac by long seminal duct surrounded by glandular material, uterus ephemeral, eggs forming rapidly in gravid segments, and seminal receptacle present. Pritchardia boliviensis n. sp. includes a single species that occurs in small marsupials in the family Didelphidae of the lowlands and Yungas of Bolivia and Atlantic forests of Paraguay. http://digitalcommons.unl.edu/parasitologyfacpubs/760/

under the coordination of Dr. Pay Drechsel. Pay has over 20 years of professionalexperience in natural resources management and has been living in Ghana for the past eightyears. He is an expert in urban agriculture in Africa, a board member of the ‘RUAFFoundation’ and in the steering committee of the CGIAR initiative ‘Urban Harvest’. Since2005, Pay has been heading IWMI’s new global research theme on "Agriculture, Water andCities". He works closely with Dr. Liqa Raschid-Sally who has more than 25 years ofprofessional experience in wastewater management in agriculture with special focus on Asiaand Africa, and Dr. Olufunke Cofie, who is the coordinator of the Network of ResourceCentres on Urban Agriculture and Food Security (RUAF) in Anglophone West Africa. Thethree are supported by a number of staff including Philip Amoah, George Danso, BernardKeraita and Emmanuel Obuobie, who started their scientific careers as MSc students inIWMI’s projects on urban and peri-urban agricul...

Integrative taxonomy was used to evaluate two component populations of Procamallanus (Spirocamallanus) inopinatus in Brazil and the phylogeny Camallanidae. Parasite populations were collected in the characiform Anostomoides passionis from River Xingu (Amazon basin) and Megaleporinus elongatus from River Miranda (Paraguay basin). Morphology was analysed using light and scanning electron microscopy (SEM). Genetic characterization was based on partial sequences of the 18S and 28S rDNA, and COI mtDNA. Phylogenies were based on 18S and COI due to data availability. Generalized Mixed Yule Coalescent (GMYC), Poisson Tree Process (PTP) and *BEAST were used for species delimitation and validation. SEM revealed for the first time the presence of minute denticles and pore-like structures surrounding the oral opening, phasmids in females and confirmed other important morphological aspects. Statistical comparison between the two-component populations indicated morphometric variations, especially...

The ribosomal RNA (rRNA) of Plasmodium berghei strain NYU2 was characterized with respect to size and used to identify molecular clones of ribosomal RNA genes (rDNA) from this organism. The intact large rRNA species (Mr 1.40 X 10(6] is intermediate in size between prokaryotic and eukaryotic large rRNAs. It is specifically cleaved in vivo near the 5'-end yielding one large component (Mr 1.10 X 10(6] and one small component (Mr 0.30 X 10(6]. The small rRNA species (Mr 0.75 X 10(6] is larger than in higher eukaryotic organisms, but is similar in size to some other protozoa. Using 5'-end labeled rRNA as a probe, clones of rDNA were selected from genomic DNA libraries prepared in lambda phage Charon 4A and plasmid pBR322. The clones prepared in lambda were prone to recombination. The 14.7 kilobase (kb) insert in phage lambda PbR27 contains the complete coding sequences for both the small and larger rRNA species. A complete set of small plasmid clones were isolated which hybridize...