Shared Food, Meals and Drinks: 10 Arguments Suggesting an Oral Transmission Route of SARS-CoV-2

: Numerous observational, epidemiologic data have suggested that the risk of COVID19 is related to shared meals or drinks. The presence of ACE2 receptors in the gastrointestinal tract supports this hypothesis. Furthermore, several patients experience gastrointestinal symptoms without any respiratory disease. The SARS-CoV-2 found on food and packaging in China and the epidemic resurgence attributed to foods are also strong indications of an oral transmission route. Unprecedented biopersistence on skin, food, and beverages supports this theory. Finally, animal models reproducing the disease by oral inoculation are additional arguments in favor of an oro-digestive route of infection.

An Attenuated Escherichia coli K88ac LT(S63K)ΔSTb Efficiently Provides Protection Against Enterotoxigenic Escherichia coli in the Mouse Model

To develop an attenuated vaccine candidate against K88ac enterotoxigenic Escherichia coli (ETEC), a novel Escherichia coli (E. coli) K88ac LT(S63K)ΔSTb with LT(S63K) mutation and ST1 deletion was generated using site mutagenesis and λ-Red homologous recombination based on wild paternal ETEC strain C83902. E. coli K88ac LT(S63K)ΔSTb showed very similar fimbriae expression and growth kinetics to the wild strain C83902, but it was significantly attenuated according to the results of a rabbit ligated ileal loop assay and mouse infection study. Oral inoculation with E. coli K88ac LT(S63K)ΔSTb stimulated the mucosa immune response and induced the secretion of IgA to K88ac in the intestines in mice. A challenge experiment revealed that the attenuated strain provided efficient protection against C83902 in the following 7 days and at the 24th day post-inoculation, suggesting that the attenuated isolate could act as an ecological protectant and vaccine in preventing K88ac ETEC.

Garlic oil as a fight against histological and oxidative stress abnormalities in Wistar rats after oral inoculation of Anisakis spp. Type II (L3) (Nematoda)

ABSTRACT The consumption of inadequately thermally treated fish is a public health risk due to the possible propagation of Anisakis larvae and their antigenic proteins, the causative agent of the zoonotic disease anisakidosis. The present study demonstrated the physiological and histopathological changes that accompanied an oral inoculation of crude extracts from fresh and thermally treated Anisakis Type II (L3) in Wistar albino rats. Nematode worms were isolated from the marine fish Dicentrarchus labrax. They were examined and taxonomically identified using light and scanning electron microscopy. The study was performed in 6 rat groups: a control group (I), a garlic oil (GO) inoculated group (II), a fresh L3 inoculated group (III), a thermally treated L3 inoculated group (IV), a fresh L3 + GO inoculated group (V), and a thermally treated L3 + GO inoculated group (VI). It was observed that rats inoculated with fresh and thermally treated L3 crude extracts showed abnormal oxidative stress markers associated with the destruction of normal architecture of spleen and thymus. GO produced a protective effect in rat groups inoculated with L3 extracts + GO administration via the amelioration of oxidative stress markers, which was confirmed by the marked normal structure of the organs’ histology. Cooking of L3 infected fish induced severe physiological and histopathological alterations compared to uncooked infected fish. The administration of garlic before and after fish eating is recommended to avoid the dangerous effect of anisakids, even if they are cooked.

The oil of garlic, Allium sativum L. (Amaryllidaceae), as a potential protectant against Anisakis spp. Type II (L3) (Nematoda) infection in Wistar rats

The consumption of inadequately thermally treated fish is a public health risk due to the possible propagation of Anisakis larvae. The present study demonstrated the physiological and histopathological changes that accompanied an oral inoculation of crude extracts from fresh and thermally treated Anisakis Type II (L3) in rats. Worms were isolated from a marine fish and examined and identified using light and scanning electron microscopy. The study was performed in 6 rat groups: control (I), garlic oil (GO) inoculated (II), fresh L3 inoculated (III), thermally treated L3 inoculated (IV), fresh L3 + GO inoculated (V), and a thermally treated L3 + GO inoculated (VI) groups. Rats inoculated with fresh and thermally treated L3 showed abnormal liver and kidney functions associated with the destruction of normal architecture. GO produced a protective effect in rat groups inoculated with L3 extracts + GO via the amelioration of liver and kidney functions, which was confirmed by the marked normal structure on histology. Cooking of L3-infected fish induced severe alterations compared to uncooked fish. The administration of garlic before and after fish eating is recommended to avoid the dangerous effect of anisakids, even if they are cooked.

Establishment and Validation of Pathogenic CS17+ and CS19+ ETEC Challenge Models in the New World Primate Aotus nancymaae

Enterotoxigenic E. coli (ETEC) are a common cause of diarrheal illness in military, travelers, and children living in low to middle income countries. Increased antibiotic resistance, the absence of a licensed vaccine and the lack of broadly practical therapeutics perpetuate the significant health and financial burden resulting from ETEC infection. A critical step in the evaluation of vaccines and therapeutics is pre-clinical screening in a relevant animal disease model that closely replicates human disease. We previously developed a diarrheal model of class 5a colonization factor (CF) CFA/I expressing ETEC in the New World owl monkey species Aotus nancymaae using ETEC strain H10407. In order to broaden the use of the model, we report here on the development of A. nancymaae models of ETEC expressing the class 5b CFs CS17 and CS19 with strains LSN03-016011/A and WS0115A, respectively. For both models, we observed diarrheal attack rates of ≥ 80% after oral inoculation with 5 × 1011 CFU of bacteria. These models will aid in assessing the efficacy of future ETEC vaccine candidates and therapeutics.

Agranulocytosis leads to intestinal Echinococcus multilocularis oncosphere invasion and hepatic metacestode development in naturally resistant Wistar rats

Susceptibility to Echinococcus multilocularis infection considerably varies among intermediate (mostly rodents) and dead-end host species (e.g. humans and pig), in particular regarding intestinal oncosphere invasion and subsequent hepatic metacestode development. Wistar rats are highly resistant to infection and subsequent diseases upon oral inoculation with E. multilocularis eggs, however, after immunosuppressive treatment with dexamethasone, rats become susceptible. To address the role of the cellular innate immunity, Wistar rats were individually or combined depleted of natural killer (NK) cells, macrophages (MΦ) and granulocytes (polymorphonuclear cells, PMN) prior to E. multilocularis egg inoculation. Although NK cell and MΦ depletion did not alter the resistance status of rats, the majority of PMN-depleted animals developed liver metacestodes within 10 weeks, indicating that PMN are key players in preventing oncosphere migration and/or development in Wistar rats. In vitro studies indicated that resistance is not caused by neutrophil reactive oxygen species or NETosis. Also, light microscopical examinations of the small intestine showed that oral inoculation of E. multilocularis eggs does not elicit a mucosal neutrophil response, suggesting that the interaction of oncospheres and neutrophils may occur after the former have entered the peripheral blood. We suggest to consider granulocytes as mediators of resistance in more resistant species, such as humans.

DELIVERY ROUTE OF CHAMOMILE ON THE GROWTH AND SUBSEQUENT PHYSIOLOGY OF BROILER CHICKENS UNDER E. COLI CHALLENGE

This experiment was conducted to investigate the effect of different levels (5g/kg ,10 g/kg or litter) of chamomile flower in feed and water on performance and gut health of broiler chickens under E. coli challenge. A total of 480-day-old Ross 308 broilers were randomly assigned to 12 treatments each replicated 4 times with 10 birds. Oral inoculation with E. coli was on days 8 and 9 of birds age. At day 10 and 35, the interaction (p<0.05) between the experimental factors decreased the feed intake in the challenged birds supplemented with chamomile. At day 10, unchallenged birds were heavier (p<0.05) than the challenged groups. Up to 35 days, birds on antibiotics (zinc bacitracin 360g/kg) and chamomile containing diets were heavier than other groups. The FCR improved in chamomile supplemented birds in both challenge conditions. Challenged birds had poorer FCR than unchallenged birds. The FCR improved in antibiotics and chamomile supplemented birds than those on control diets. The intestinal pH, serum lipid content decreased and serum protein profile improved by chamomile supplementation. The interaction of the experimental factors increased (p<0.0001) protein digestibility in the unchallenged birds supplemented with chamomile in their diets. Protein digestibility improved (p<0.001) in chamomile supplemented birds. The interaction of the experimental factors increased fat digestibility (p<0.0001) in the challenged birds on the lower level of dietary chamomile. Fat digestibility was higher (p<0.0001) but protein digestibility and villi were lower in the challenged birds than unchallenged groups. Longer villi were observed in the unchallenged birds on the lower level of chamomile in their drinking water and those on the highest level of dietary chamomile