Platelets Can Associate with SARS-Cov-2 RNA and Are Hyperactivated in COVID-19.

Rationale: In addition to the overwhelming lung inflammation that prevails in COVID-19, hypercoagulation and thrombosis contribute to the lethality of subjects infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Platelets are chiefly implicated in thrombosis. Moreover, they can interact with viruses and are an important source of inflammatory mediators. While a lower platelet count is associated with severity and mortality, little is known about platelet function during COVID-19. Objective: To evaluate the contribution of platelets to inflammation and thrombosis in COVID-19 patients. Methods and Results: Blood was collected from 115 consecutive COVID-19 patients presenting non-severe (n=71) and severe (n=44) respiratory symptoms. We document the presence of SARS-CoV-2 RNA associated with platelets of COVID-19 patients. Exhaustive assessment of cytokines in plasma and in platelets revealed the modulation of platelet-associated cytokine levels in both non-severe and severe COVID-19 patients, pointing to a direct contribution of platelets to the plasmatic cytokine load. Moreover, we demonstrate that platelets release their alpha- and dense-granule contents in both non-severe and severe forms of COVID-19. In comparison to concentrations measured in healthy volunteers, phosphatidylserine-exposing platelet extracellular vesicles were increased in non-severe, but not in severe cases of COVID-19. Levels of D-dimers, a marker of thrombosis, failed to correlate with any measured indicators of platelet activation. Functionally, platelets were hyperactivated in COVID-19 subjects presenting non-severe and severe symptoms, with aggregation occurring at suboptimal thrombin concentrations. Furthermore, platelets adhered more efficiently onto collagen-coated surfaces under flow conditions. Conclusions: Taken together, the data suggest that platelets are at the frontline of COVID-19 pathogenesis, as they release various sets of molecules through the different stages of the disease. Platelets may thus have the potential to contribute to the overwhelming thrombo-inflammation in COVID-19, and the inhibition of pathways related to platelet activation may improve the outcomes during COVID-19.

An Evaluation of Three Different Primary Equine Influenza Vaccination Intervals in Foals.

In order to evaluate the effect of three different primary vaccination intervals on EI vaccine response, 21 unvaccinated thoroughbred foals were randomly divided into three groups of 7 and vaccinated with three different intervals of primary immunization (i.e., with 1, 2 or 3 months intervals between V1 and V2, respectively). The antibody response was measured for up to 1 year after the third immunization V3 (administered 6 months after V2) by single radial hemolysis (SRH) assay. All weanlings had seroconverted and exceeded the clinical protection threshold 2 weeks after V2 and 1 month after V3 until the end of the study. Significant differences were measured at the peak of immunity after V2 and for the duration of the immunity gap between V2 and V3. The group with one month primary vaccination interval had a lower immunity peak after V2 (158.05 ± 6.63 mm2) and a wider immunity gap between V2 and V3 (18 weeks) when compared with other groups (i.e., 174.72 ± 6.86 mm2 and 16 weeks for a two months interval, 221.45 ± 14.48 mm2 and 12 weeks for a 3-month interval). The advantage observed in the group with 1 month primary vaccination interval, which induces an earlier protective immunity, is counterbalance with a lower peak of immunity and a wider immunity gap after V2, when compared with foals vaccinated with 2- and 3-month intervals.

Evaluation of integrated control of three dog transmitted zoonoses: Rabies, visceral leishmaniasis and cystic echinococcosis, in Morocco.

The present study is a component of a major European research project, ICONZ (Integrated Control of Neglected Zoonoses). The objective of this component was to implement, and then evaluate an Integrated Control Intervention (ICI) against three dog transmitted zoonoses, namely rabies, visceral leishmaniasis, and cystic echinococcosis. This was undertaken in Sidi Kacem Province (northwestern Morocco) where 22 control and 22 treated douars (villages) were randomly allocated to two control and one evaluation interventions over a period of 13 months. Across the 44 douars, an overall total of 6922 dogs were registered, 4519 were vaccinated against rabies, and 2885 persons attended the complementary health education campaigns; whereas, within the 22 treated douars, 466 dogs received anti-sandfly collars (deltamethrin-impregnated) and 2487 were dewormed (praziquantel). Evaluation of the ICI, revealed that (i) a canine rabies vaccination coverage of 65.0% was achieved, (ii) the use of deltamethrin-impregnated collars for dogs provided highly significant protection (p = 0.01) against leishmaniasis infection of more than 44%, and up to 100% for dogs that had kept the collar until the end of the intervention, (iii) despite a non-significant difference (p>0.05), dog-deworming with praziquantel yielded a reduction in the rate of Echinococcus granulosus infection, and (iv) health education was successful in improving respondents' knowledge; However, the target communities remained unconvinced of the necessity of changing some of their risky behaviours. Lastly, the estimated total cost of the global intervention, including its research components, was US$ 143,050, of which 67% was for disease control work with clear evidence of significant economies of scale due to targeting three diseases together. It appears from this study that the integrated control approach against the three zoonoses was effective on both economic and logistical levels.

Serological investigation of racehorse vaccination against equine influenza in Morocco.

In order to evaluate the vaccination status against equine influenza (EI) in Moroccan racehorses, a serological investigation was carried out on 509 racehorses using three serological tests: an Enzyme-Linked Immunosorbent Assay (ELISA), the Hemagglutination Inhibition (HI) test and the Single Radial Haemolysis (SRH) assay. The serological analysis showed 56% of seropositivity by ELISA, 67% by HI and 89.4% by SRH (with 69.9% above the clinical protection threshold). Using the Kappa test, the SRH and HI assays showed a strong agreement, the SRH and ELISA assays had a moderate agreement and the HI and ELISA assays showed a poor agreement. Seropositivity was positively correlated with the age of horses and the number of immunisation received. EI vaccines used during the last immunisation before the study had a weak influence on the serological status. This effect was observed when the vaccines Calvenza and Fluvac Innovator® were used, with 94.1% and 100% of seropositivity when measured by HI, and with 100% and 94.7% exceeding the clinical protection threshold when measured by SRH, respectively. No effect was found when other EI vaccines, including Prequenza-Te® (67% coverage (342/509) and Proteqflu-Te® (22% coverage (114/509) were used; with 64% and 67.5% seropositivity (HI) and with 66.4% and 72.8% above the clinical threshold (SRH), respectively. The location and the time since last vaccination have no influence on the serological result. Overall, levels of protective antibody against EI in Moroccan racehorses remain a concern despite mandatory vaccination.