Viral shedding and viraemia of Andes virus during acute hantavirus infection: a prospective study

BACKGROUND

Andes virus (ANDV) is a zoonotic Orthohantavirus leading to hantavirus cardiopulmonary syndrome. Although most transmissions occur through environmental exposure to rodent faeces and urine, rare person-to-person transmission has been documented, mainly for close contacts. This study investigates the presence and infectivity of ANDV in body fluids from confirmed cases and the duration of viraemia.

METHODS

In this prospective study, 131 participants with confirmed ANDV infection were enrolled in Chile in a prospective study between 2008 and 2022. Clinical samples (buffy coat, plasma, gingival crevicular fluid [GCF], saliva, nasopharyngeal swabs [NPS], and urine) were collected weekly for 3 weeks together with clinical and epidemiological data. Samples were categorised as acute or convalescent (up to and after 16 days following onset of symptoms). Infectivity of positive fluids was assessed after the culture of samples on Vero E6 cells and use of flow cytometry assays to determine the production of ANDV nucleoprotein.

FINDINGS

ANDV RNA was detected in 100% of buffy coats during acute phase, declining to 95% by day 17, and to 93% between days 23-29. ANDV RNA in GCF and saliva decreased from 30% and 12%, respectively, during the acute phase, to 12% and 11% during the convalescent phase. Successful infectivity assays of RT-qPCR-positive fluids, including GCF, saliva, NPS, and urine, were observed in 18 (42%) of 43 samples obtained during the acute phase of infection. After re-culture, the capacity to infect Vero E6 cells was maintained in 16 (89%) of 18 samples. Severity was associated with the presence of ANDV RNA in one or more fluids besides blood (odds ratio 2·58 [95% CI 1·42-5·18]).

INTERPRETATION

ANDV infection is a systemic and viraemic infection, that affects various organs. The presence of infectious particles in body fluids contributes to our understanding of potential mechanisms for person-to-person transmission, supporting the development of preventive strategies. Detection of ANDV RNA in additional fluids at hospital admission is a predictor of disease severity.

FUNDING

None.

TRANSLATION

For the Spanish translation of the abstract see Supplementary Materials section.

Oxidized low density lipoproteins induce apoptosis in human lymphocytes: involvement of mitogen-activated protein kinases

Oxidized low density lipoproteins (oxLDL), macrophages and T-lymphocytes are present in atherosclerotic lesions. We and others have shown that oxLDL is cytotoxic for macrophages, endothelial, smooth muscle and activated T-lymphocytes and induce apoptosis. Here we demonstrate that (i) oxidized LDL (oxLDL), oxidized VLDL (oxVLDL) and hydrogen peroxide (H2O2) induce apoptosis in human T-lymphocytes and (ii) mitogen-activated protein kinases are involved in this process. Apoptosis was monitored by immunofluorescence microscopy and flow cytometry for annexin V binding, Apo 2.7 expression, the TUNEL reaction and caspase 3 activity. In the presence of oxLDL (100 microg/ml), oxVLDL (50 microg/ml) and H2O2 (5 mM), the fraction of apoptotic cells increased within 6 hours to more than 70%. Preincubation of lymphocytes with the MAPKK inhibitor PD-98059 and the p38MAPK inhibitor SB-203580 almost completely abolished these effects. Furthermore, oxLDL and H2O2 but not native LDL strongly enhanced phosphorylation of JNK, p38MAPK and p42/44MAPK. The results suggest that in the resting lymphocyte apoptosis triggered by oxidized lipoproteins and oxidative stress depends on the activation of p44/42MAPK and p38MAPK cascades.

Haemophilus species bacteremia in adults. The importance of the human immunodeficiency virus epidemic

BACKGROUND

Until the late 1970s, invasive infections caused by Haemophilus species were thought to occur mainly in children and only infrequently in adults.

OBJECTIVE

To report the largest series to date of Haemophilus species bacteremia (HB) from a single center.

DESIGN

Retrospective.

SETTING

Large, tertiary care, general teaching hospital.

METHODS

We reviewed the charts of adult patients with HB detected from January 1, 1986, to December 31, 1994. Haemophilus strains were serotyped, and the antimicrobial resistance pattern was analyzed.

RESULTS

One hundred sixteen patients had HB (0.26 cases per 1000 admissions). Thirty-eight children and 16 adults were excluded. Human immunodeficiency virus (HIV) infection was the most common underlying condition (n = 18 [29%]), followed by malignant neoplasms (n = 12 [19%]) and chronic obstructive pulmonary disease (n = 12 [19%]). Prevalence in HIV-positive patients was 5 cases per 1000 admissions vs 0.2 cases per 1000 admissions in HIV-negative patients. Infection was nosocomial in 16 patients (26%). Focal diseases were pneumonia in 41 patients (66%), cholangitis in 5 patients (8%), endocarditis in 3 patients (5%), meningitis and septic arthritis each in 1 patient (2%), and primary bacteremia in 9 patients (14%). The HIV-positive patients were significantly younger and presented more frequently with pneumonia (P < .05). Overall, 14 patients died (22%). Bacteremia was polymicrobial in 11 patients (18%). Haemophilus influenzae was isolated in 53 patients (85%). Rates of antimicrobial resistance were 11% to chloramphenicol sodium succinate, 48% to ampicillin sodium, 78% to erythromycin stearate, 76% to combined sulfamethoxazole and trimethoprim, 15% to rifampin, and 57% to clarithromycin.

CONCLUSIONS

Infection with HIV has become the most common underlying disease in adults with HB in our hospital. Therapeutic approaches must take into account the high rate of antimicrobial resistance.

Group B streptococcus bacteremia in nonpregnant adults

BACKGROUND

We report the largest series of group B streptococcal (GBS) bacteremia cases reported at a single institution.

METHODS

During a 10-year period (1985-1994), 90 GBS bacteremia cases (0.95% of significant bacteremic episodes) were detected. We describe the 51 episodes that occurred in nonpregnant adults for which enough clinical and microbiological information is available.

RESULTS

Incidence of GBS has significantly increased during the study period (from 0.08 per 1000 admissions in 1985 to 0.3 per 1000 in 1994). Mean age of patients was 63.3 years (range, 21-88 years) and 53% were men. The most common underlying conditions were liver diseases (35.3%), malignancies (33.3%), and diabetes mellitus (27.5%). Only 2 patients did not have any underlying condition and no patient with the human immunodeficiency virus had GBS bacteremia in our series. The origins of the episodes of bacteremia were as follows: primary bacteremia (39.2%), skin and soft tissue infections (15.7%), urinary tract infections (11.8%), pneumonia (9.8%), peritonitis (9.8%), catheter infection (5.9%), postendoscopic bacteremia (5.9%), and endocarditis (2%). All isolates were susceptible to penicillin G potassium, ampicillin sodium, cephalothin sodium, cefotaxime sodium, and vancomycin hydrochloride. One ciprofloxacin hydrochloride-resistant strain was discovered and resistance to erythromycin stearate increased from 8% in 1992 to 18% in 1994. The overall mortality rate was 33.3% and deaths were considered related to the GBS bacteremia in 25.5% of the cases. Factors for poor prognosis were central nervous system diseases, alcoholism, shock, renal failure, and consciousness impairment.

CONCLUSIONS

Group B streptococcus is a rising cause of bacteremia in elderly patients with severe underlying conditions. It conveys high morbidity and mortality rates. Macrolides should not be used empirically for treatment of patients with penicillin allergies.