Francisco Brito

Astrovirus MLB2, a New Gastroenteric Virus Associated with Meningitis and Disseminated Infection

This virus is an unrecognized cause of central nervous system infection, particularly among immunocompromised patients.

Novel human astroviruses: Novel human diseases?

Astroviruses are small, non-enveloped, single-stranded positive RNA viruses that belong to the Astroviridae family. While classical human astroviruses (HAstV) are a well-recognized cause of acute non-bacterial diarrhea among young children worldwide, novel astroviruses, named HAstV-MLB and HAstV-VA/HMO, have been identified recently in humans by molecular assays. They are phylogenetically more related to animal astroviruses than to classical human astroviruses, thus suggesting cross-species transmission. Serological studies demonstrated a surprisingly high seroprevalence in certain populations and highlighted a high infection rate in the early years of life. Although their pathogenic role has not yet been clearly determined, novel astrovirus RNA sequences have been identified in different biological specimens of symptomatic patients, including the feces, plasma, cerebrospinal fluid, and brain biopsies. Thus, there is evidence that they could contribute not only to digestive tract infection, but also to unexpected clinical syndromes, notably encephalitis and meningitis. Severe infections affect mainly immunocompromised patients. These findings indicate that novel astroviruses should be considered in the differential diagnosis of immunocompromised patients with meningitis or encephalitis of unknown origin.

Rhinoconjunctivitis and asthma caused by vine pollen: A case report

BACKGROUND The vine (Vitis vinifera) is a cultivated plant that is found in some European and American countries. Its pollen gathers in small quantities during a short pollination period in the months of May and June. Allergy to vine pollen has not been previously documented. OBJECTIVE We sought to describe a case report of allergy to vine pollen documented on the basis of anamnesis, cutaneous, provocation, and specific IgE determination tests. METHODS An allergenic extract was obtained from collected V vinifera pollens by aqueous standard procedures. Pollen counts and pollination periods of this and other common pollens in the area where the patient became symptomatic were studied. Cutaneous tests and the presence of specific IgE to the pollen extracts were performed by prick, CAP, and RAST techniques. Bronchial and conjunctival tests with the involved pollen extracts were also carried out to identify the sensitizing allergens. Five healthy subjects and 5 pollinic patients were used as control subjects and underwent the same tests. RESULTS Skin prick test responses with vine pollen at different concentrations were positive for the studied patient and negative for the control subjects. Patient serum revealed a total IgE titer of 334 IU/mL and a specific IgE value of 1.3 PRU/mL (RAST class 2) to vine pollen. Bronchial and conjunctival provocation test responses were also positive when the patient was challenged with V vinifera extract. CONCLUSION Exposure to the pollen of the vineyard plants (V vinifera) can induce immunologic sensitization and rhinoconjunctivitis/asthma.

Astrovirus VA1 identified by next-generation sequencing in a nasopharyngeal specimen of a febrile Tanzanian child with acute respiratory disease of unknown etiology

Astrovirus VA1 identified by next-generation sequencing in a nasopharyngeal specimen of a febrile Tanzanian child with acute respiratory disease of unknown etiology

Propagation of respiratory viruses in human airway epithelia reveals persistent virus-specific signatures

Background: The leading cause of acute illnesses, respiratory viruses, typically cause self‐limited diseases, although severe complications can occur in fragile patients. Rhinoviruses (RVs), respiratory enteroviruses (EVs), influenza virus, respiratory syncytial viruses (RSVs), and coronaviruses are highly prevalent respiratory pathogens, but because of the lack of reliable animal models, their differential pathogenesis remains poorly characterized. Objective: We sought to compare infections by respiratory viruses isolated from clinical specimens using reconstituted human airway epithelia. Methods: Tissues were infected with RV‐A55, RV‐A49, RV‐B48, RV‐C8, and RV‐C15; respiratory EV‐D68; influenza virus H3N2; RSV‐B; and human coronavirus (HCoV)–OC43. Replication kinetics, cell tropism, effect on tissue integrity, and cytokine secretion were compared. Viral adaptation and tissue response were assessed through RNA sequencing. Results: RVs, RSV‐B, and HCoV‐OC43 infected ciliated cells and caused no major cell death, whereas H3N2 and EV‐D68 induced ciliated cell loss and tissue integrity disruption. H3N2 was also detected in rare goblet and basal cells. All viruses, except RV‐B48 and HCoV‐OC43, altered cilia beating and mucociliary clearance. H3N2 was the strongest cytokine inducer, and HCoV‐OC43 was the weakest. Persistent infection was observed in all cases. RNA sequencing highlighted perturbation of tissue metabolism and induction of a transient but important immune response at 4 days after infection. No majority mutations emerged in the viral population. Conclusion: Our results highlight the differential in vitro pathogenesis of respiratory viruses during the acute infection phase and their ability to persist under immune tolerance. These data help to appreciate the range of disease severity observed in vivo and the occurrence of chronic respiratory tract infections in immunocompromised hosts.

Metagenomics analysis of red blood cell and fresh-frozen plasma units

Although the risk of transmitting infectious agents by blood transfusion is dramatically reduced after donor selection, leukoreduction, and laboratory testing, some could still be present in donors blood. A description of metagenomes in blood products eligible for transfusion represents relevant information to evaluate the risk of pathogen transmission by transfusion.

Rhinoconjunctivitis and asthma caused by corn plant (Dracaena fragrans).

BACKGROUND Respiratory symptoms caused by decorative flowers have seldom been reported in the literature. OBJECTIVE To describe a housewife who experienced episodes of asthma, rhinoconjunctivitis, and contact urticaria in relation to corn plant (Dracaena fragrans) in her home. METHODS Skin prick testing (SPT) was performed with extract from the leaves of D. fragrans and a standard battery of aeroallergens. An air sampler was installed close to the plant in her house. We performed skin, conjunctival, and bronchial provocation tests with the extract of D. fragrans. Serum specific IgE was measured using enzyme allergosorbent testing. RESULTS The patient showed positive SPT reactions to the D. fragrans extract at a concentration of 0.05 mg/mL. Results of SPT with the extract prepared from the Air Sentinel filter were also positive. Skin provocation testing with the leaves of corn plant on the patients forearm provoked dense wheal formation. The conjunctival provocation test response was positive to an antigen concentration of 0.05 mg/mL. The peak expiratory flow rate varied by 20% to 40% on exposure days and by 5% to 10% on nonexposure days. The bronchial provocation test response was positive to an antigen concentration of 0.5 mg/mL. Specific IgE to D. fragrans extract was 15.1 kUA/L. CONCLUSIONS These findings strongly suggest that an IgE-mediated immunologic mechanism is responsible for the patients respiratory and cutaneous symptoms in relation to corn plant.

Metagenomics analysis of the virome of 300 concentrates from a Swiss platelet bank

Platelet concentrates are frequently transfused to patients with reduced immunity. An exhaustive description of their viral content is needed to prevent unwanted infection.