Gene therapies and COVID-19 vaccines: a necessary discussion in relation with viral vector-based approaches.

The COVID-19 pandemic is adding an unanticipated concern for those affected by genetic diseases. Most of the new treatment achievements for these patients are made possible as a result of advances in viral-based products. Among them, adenoviruses (AdV) and especially adeno-associated viruses (AAV) are important players. The concerns and the conversation around this issue have increased as COVID-19 vaccines approach the market. What if the viral vectors become the mainstream strategy for vaccine development? Will the immune response elicited against the vector compromise the efficacy of future gene therapies? Patients with genetic diseases and patient advocacy groups are requesting information to the medical community about the potential impact of these vaccines in future gene therapy treatments, and physicians and scientists are not able to provide satisfactory answer yet. Importantly, the frequency of cross-reactivity among different AAV serotypes can be as high as 50%. This would have potential implications for patients with genetic disorders who could benefit from gene therapies, often coming in the form of AAV-based gene therapies. As in many other aspects, this pandemic is challenging our capacity to coordinate, plan ahead and align different medical objectives. In this case, having such conversation early on might allow us to make the right choices while we are still on time.

Nonclinical data supporting orphan medicinal product designations in the area of rare infectious diseases.

This review provides an overview of nonclinical in vivo models that can be used to support orphan designation in selected rare infectious diseases in Europe, with the aim to inform and stimulate the planning of nonclinical development in this area of often neglected diseases.

Disinfection of drinking water contaminated with Cryptosporidium parvum oocysts under natural sunlight and using the photocatalyst TiO2.

The results of a batch-process solar disinfection (SODIS) and solar photocatalytic disinfection (SPCDIS) on drinking water contaminated with Cryptosporidium are reported. Cryptosporidium parvum oocyst suspensions were exposed to natural sunlight in Southern Spain and the oocyst viability was evaluated using two vital dyes [4',6-diamidino-2-phenylindole (DAPI) and propidium iodide (PI)]. SODIS exposures (strong sunlight) of 8 and 12h reduced oocyst viability from 98% (+/-1.3%) to 11.7% (+/-0.9%) and 0.3% (+/-0.33%), respectively. SODIS reactors fitted with flexible plastic inserts coated with TiO2 powder (SPCDIS) were found to be more effective than those which were not. After 8 and 16 h of overcast and cloudy solar irradiance conditions, SPCDIS reduced oocyst viability from 98.3% (+/-0.3%) to 37.7% (+/-2.6%) and 11.7% (+/-0.7%), respectively, versus to that achieved using SODIS of 81.3% (+/-1.6%) and 36.0% (+/-1.0%), respectively. These results confirm that solar disinfection of drinking water can be an effective household intervention against Cryptosporidium contamination.

Cryptosporidium and Giardia in wild otters (Lutra lutra).

A total of 437 faecal samples from wild otter (Lutra lutra) were collected from 161 sites in Galicia (northwest Spain) and were analysed by a direct immunofluorescence antibody test (IFAT). Cryptosporidium sp. oocysts and Giardia sp. cysts were detected in 17 (3.9%) and 30 (6.8%) samples, respectively. The results demonstrate that otters may contribute to the contamination of watercourses, although further studies are required to establish which species or genotypes of Cryptosporidium and Giardia infect these animals and also the significance in terms of public health.

Artemia is capable of spreading oocysts of Cryptosporidium and the cysts of Giardia.

The capability for ingesting and spreading the fixed oocysts of Cryptosporidium and fixed cysts of Giardia, two waterborne protozoan parasites, by Artemia franciscana, a microcrustacean widely used as live diet in fish and shellfish larviculture, was demonstrated using differential interference contrast and immunofluorescence microscopy. Our findings suggest the possibility that this microcrustacean could serve as a disseminating vehicle of both parasites in aquatic environments.

Levels of detection of Cryptosporidium oocysts in mussels (Mytilus galloprovincialis) by IFA and PCR methods.

Cryptosporidium spp. are monoxenous protozoan parasites that cause gastrointestinal diseases in humans and animals. Shellfish harvesting areas can become contaminated by the infectious stage of the parasite and humans are therefore at risk of infection either by consumption of shellfish, or by taking part in recreational activities in these areas. In the present study we determined the levels of detection, by IFA and PCR techniques, of Cryptosporidium oocysts in mussels experimentally contaminated with a theoretical number of oocysts. There was a significant correlation between the results obtained by both techniques (P<0.05). IFA and PCR were also applied to a total of 222 samples of mussels (Mytilus galloprovincialis) destined for human consumption. In the naturally contaminated samples, we detected a 31.1% of contamination and only Cryptosporidium parvum (previously denominated C. parvum genotype II) was identified.

Cooking mussels (Mytilus galloprovincialis) by steam does not destroy the infectivity of Cryptosporidium parvum.

The consumption of shellfish has increased considerably worldwide, with an associated increase in foodborne illnesses. Among the bivalves, the mussels are usually cooked by steam, which constitutes a typical dish in several regions. In this article, we demonstrate that this preparation is not sufficient to destroy completely the infectivity of Cryptosporidium parvum. Oocysts recovered from experimentally contaminated mussels (Mytilus galloprovincialis) were infectious to neonatal mice after cooking. Although, to date, no official cases of cryptosporidiosis linked to shellfish consumption have been reported, we recommend that people with reduced immunity avoid this type of food because they are at high risk of being infected with Cryptosporidium spp. after eating raw or undercooked contaminated bivalves.

Cryptosporidium contamination in harvesting areas of bivalve molluscs.

Cryptosporidium contamination was evaluated in areas in Galicia (northwestern Spain) where bivalve molluscs are harvested. Galicia is the main mussel-producing region in Europe. Data were collected on water contamination of effluents that are discharged into these areas. Cryptosporidium spp. were detected by immunofluorescence microscopy and molecular methods in 71% of the river water samples (n = 7), 64% of raw sewage samples (n = 11), 50% of effluents from wastewater treatment plants (n = 16), and 29.3% of the mussel samples (Mytilus galloprovincialis, n = 184). Cryptosporidium parvum was identified in all samples of contaminated mussels, Cryptosporidium muris was found in three samples of effluent from wastewater treatment plants, and Cryptosporidium baileyi was found in a sample of raw sewage. Further studies are needed to determine the parasitological quality of water in these shellfish harvesting and recreational areas. Cryptosporidium could be a public health risk from consumption of raw or undercooked contaminated molluscs and use of contaminated waters for recreational purposes.

Giardia in shellfish-farming areas: detection in mussels, river water and waste waters.

Giardia cyst contamination of mussels (Mytilus galloprovincialis), raw and treated waste waters and water from rivers that flow into four Galician estuaries (NW Spain), where bivalve molluscs are cultured for human consumption, was studied. The high prevalence of contamination in mussels (41.8%, n=184), raw waste water (90.9%, n=11), treated waste water (87.5%, n=16) and in samples of river water (85.7%, n=7), with cyst counts of 9.8-1800.0, 7.0-2541.0 and 1.0-29.3 cysts l(-1), respectively, illustrate the wide distribution of this enteropathogen in the environment and the potential risk to public health associated with the consumption of raw or undercooking bivalves and use of these estuaries for recreational purposes.

Occurrence of giardia cysts in mussels (Mytilus galloprovincialis) destined for human consumption.

Between January and June 2004, a total of 200 nondepurated mussel samples of the Galician coast (northwest Spain) were examined for Giardia cysts with a direct immunofluorescence antibody test. Giardia cysts were found in mussels from all of the estuaries studied, with an overall rate of contamination of 41.5%. There was relation between the presence of Giardia cysts, the microbiological contamination (expressed as most probable number of Escherichia coli) detected in the samples, and the harvesting area. This is the first work that describes the presence of Giardia cysts in mussels (Mytilus galloprovincialis) destined for human consumption.