To investigate age-related differences in dengue severity, 114 infants, 1,211 children, and 346 adults with laboratory-confirmed dengue virus (DEN) infections presenting to three hospitals in major urban centers in Nicaragua were recruited from 1999 to 2001. The age distribution of dengue cases and the circulating serotype (predominantly DEN2) were representative of national data. Similar results were obtained when either dengue hemorrhagic fever/dengue shock syndrome or its principal manifestations (vascular permeability, internal hemorrhage, marked thrombocytopenia, and/or shock) were analyzed in relation to age and immune status. The burden of disease and of severe dengue was found predominantly in infants 4-9 months of age and in children 5-9 years old, and secondary DEN infection was a risk factor for severity in children. Age-related differences were identified in the prevalence of specific clinical manifestations as well as in their association with a confirmed DEN diagnosis. This represents one of the few comprehensive studies to analyze characteristics of dengue in infants, children, and adults in the same population and highlights age-related differences in dengue severity.

Up to 22 June 2022, 508 confirmed cases of monkeypox (MPX) have been reported in the Madrid region of Spain, 99% are men (n = 503) with a median age of 35 years (range: 18–67). In this ongoing outbreak, 427 cases (84.1%) reported condomless sex or sex with multiple partners within the 21 days before onset of symptoms, who were predominantly men who have sex with men (MSM) (n = 397; 93%). Both the location of the rash, mainly in the anogenital and perineal area, as well as the presence of inguinal lymphadenopathy suggest that close physical contact during sexual activity played a key role in transmission. Several cases reported being at a sauna in the city of Madrid (n = 34) or a mass event held on the Spanish island of Gran Canaria (n = 27), activities which may represent a conducive environment for MPX virus spread, with many private parties also playing an important role. Because of the rapid implementation of MPX surveillance in Madrid, one of the largest outbreaks reported outside Africa was identified. To minimise transmission, we continue to actively work with LGBTIQ+ groups and associations, with the aim of raising awareness among people at risk and encouraging them to adopt preventive measures.

Dengue, the most prevalent arthropod-borne viral disease of humans, is caused by four serotypes of dengue virus (DENV 1-4). Although all four DENV serotypes cause a range of illness, defining precisely which clinical characteristics are associated with the distinct serotypes has been elusive. A cross-sectional study was conducted on 984 and 313 hospitalized children with confirmed DENV infections during two time periods, respectively, in the same hospitals in Nicaragua: a 3-year period (1999-2001) when DENV-2 accounted for 96% of the viruses identified, and the 2003 dengue season when DENV-1 predominated (87% of identified serotypes). When the two periods were compared, more shock (OR 1.91, 95% CI 1.35-2.71) and internal hemorrhage (OR 2.05, CI 1.16-3.78) were observed in the period when DENV-2 predominated, whereas increased vascular permeability was associated to a greater degree with the DENV-1 period (OR 2.36, CI 1.80-3.09). Compared with the DENV-2 period, the DENV-1 season was associated with more hospitalized primary dengue cases (OR 3.86, CI 2.72-5.48) and more primary DENV infections with severe manifestations (OR 2.93, CI 2.00-4.28). These findings provide new data to characterize the pathogenic potential of distinct DENV serotypes in human populations.

Dengue is a major public health problem worldwide and continues to increase in incidence. Dengue virus (DENV) infection leads to a range of outcomes, including subclinical infection, undifferentiated febrile illness, Dengue Fever (DF), life-threatening syndromes with fluid loss and hypotensive shock, or other severe manifestations such as bleeding and organ failure. The long-standing World Health Organization (WHO) dengue classification and management scheme was recently revised, replacing DF, Dengue Hemorrhagic Fever (DHF), and Dengue Shock Syndrome (DSS) with Dengue without Warning Signs, Dengue with Warning Signs (abdominal pain, persistent vomiting, fluid accumulation, mucosal bleeding, lethargy, liver enlargement, increasing hematocrit with decreasing platelets) and Severe Dengue (SD; dengue with severe plasma leakage, severe bleeding, or organ failure). We evaluated the traditional and revised classification schemes against clinical intervention levels to determine how each captures disease severity using data from five years (2005–2010) of a hospital-based study of pediatric dengue in Managua, Nicaragua. Laboratory-confirmed dengue cases (n = 544) were categorized using both classification schemes and by level of care (I–III). Category I was out-patient care, Category II was in-patient care that did not meet criteria for Category III, which included ICU admission, ventilation, administration of inotropic drugs, or organ failure. Sensitivity and specificity to capture Category III care for DHF/DSS were 39.0% and 75.5%, respectively; sensitivity and specificity for SD were 92.1% and 78.5%, respectively. In this data set, DENV-2 was found to be significantly associated with DHF/DSS; however, this association was not observed with the revised classification. Among dengue-confirmed cases, the revised WHO classification for severe dengue appears to have higher sensitivity and specificity to identify cases in need of heightened care, although it is no longer as specific for a particular pathogenic entity as was the traditional schema.