The two most common Trichinella species causing human disease are T. spiralis and T. pseudospiralis belonging to encapsulated and non-encapsulated clades, respectively. Upon invasion, the larva of T. spiralis not only occupies and develops inside the muscle cell but also transforms it into a nurse cell surrounded by the vascular network called circulatory rete. It has been postulated that vascular endothelial growth factor (VEGF) is involved in the rete formation leading to the development and maintenance of nurse cell. This study showed that the expression of VEGF in the nurse cell of T. spiralis and T. pseudospiralis was detected by in situ hybridization. Basal expression of VEGF was found in uninfected muscle by real-time PCR technique and Western blot analysis. Nevertheless, both methods were not able to demonstrate the increase of VEGF expression above the basal expression in muscles infected with T. spiralis or T. pseudospiralis. The unexpected results are probably due to the relatively small number of infected nurse cells which could not produce enough positive signals to show significant increase in VEGF expression. It is likely that VEGF plays a role in the formation of circulatory rete and nurse cell in T. spiralis infection. However, there has been no experiment to directly validate this hypothesis. This area of study should be further investigated.

This paper aim to provide information in the major parasitic pathogens found in Mediterranean mussel, Mytilus galloprovincialis from south Mediterranean population of the bay of M’diq, in Morocco. The parasitic prevalence in relation to the reproductive cycle and the environmental conditions were investigated, and potential determinants of the infection were discussed. Mussels were monthly collected from March 2009 to March 2011. To examine the reproductive stage of the M. galloprovincialis and pathological status, histological approach was taken for the analysis. Common parasites including regionally problematic Marteilia refringens were observed in the specimen. We found the Ciliophora-like Protozoan group in digestive diverticula (43.33% of hosts). Steinhausia mytilovum is observed in oocytes of the host, and its prevalence was up to 32%. The presence and absence of the Ciliophora-like group had a significant relationship with variation of salinity in the site (p<0.05), and the presence and absence of the S. mytilovum had a significant relationship with change in the gonadic index (p< 0.05). The negative impact of parasites upon the local population of M. galloprovincialis at the site was not major during the surveyed years. No mortality due to the parasitic diseases has been observed in mussels in M’diq. However, the found relationships between the parasite and host and environmental condition suggest that the variability of the environment in the site would cause unanticipated outbreaks. Considering the importance of mussels for Moroccan mytilicultre in the southern Alboran, comprehensive monitoring of the pathological status and host and environmental condition is necessary.

Giardia duodenalis (G. lamblia, G. intestinalis) is an enteric protozoan that infects human beings and a wide range of domestic and wild mammals. Giardiasis is considered a parasitic zoonosis by the World Health Organization, and they highlight the importance of animals as Giardia transmitters. This parasite is prevalent in areas with a temperate, humid climate, with heterogeneous distribution and the highest infection prevalences found in developing countries. The molecular characterization of Giardia duodenalis has permitted the identification of eight morphologically indistinguishable genotypes (A, B, C, D, E, F, G, H) with different host specificity. Several molecular studies have established the presence of genotypes A and B in both humans and animals throughout the world. The clinical presentation of giardiasis in humans is highly varying, ranging from asymptomatic manifestations to chronic diarrhea with malabsorption and childhood stunting. The significant aspects of Giardia infection are discussed in this review, and new progresses in topics such as taxonomy, biology, physio-pathogenesis, molecular epidemiology, zoonotic potential, clinical presentation of the infection and treatment of this parasite are emphasized.