This study aimed to analyse the seroprevalence of SARS-CoV-2 in Kazakhstan. This is a cross-sectional study of adult population in Kazakhstan for the period from October 2021 to May 2022. For the study, 6 720 people aged 18 to 69 were recruited (from 17 regions). The demographic data were collected and analysed. Gender was evenly distributed (males 49.9%, females 50.1%). Women exhibited a higher seroprevalence than men (IgM 20.7% vs 17.9% and IgG 46.1% vs 41.5%). The highest prevalence of IgM was found in the age group of 30–39. However, the highest prevalence of IgG was detected in the age group of 60–69. The seroprevalence of IgG increased across all groups (from 39.7% in 18–29 age groups to 53.1% in 60–69 age groups). The odds for a positive test were significantly increased in older age groups 50–59 (p < 0.0001) and 60–69 (p < 0.0001). The odds of a positive test were 1.12 times higher in females compared to males (p = 0.0294). The odds for a positive test were significantly higher in eight regions (Astana, Akmola, Atyrau, Western Kazakhstan region, Kostanai, Turkestan, Eastern Kazakhstan region, and Shymkent) compared to Almaty city. The odds of a positive test were three times higher in Astana and the Western Kazakhstan region than in Almaty city. In urban areas, the odds of a positive test were 0.75 times lower than in rural areas (p < 0.0001). The study’s results showed an adequate level of seroprevalence (63%) that exceeds the essential minimum of herd immunity indicators in the country. There was significant geographic variability with a higher prevalence of IgG/IgM antibodies to SARS-CoV-2 in rural areas.

Much of our current understanding about novel coronavirus disease 2019 (COVID-19) comes from hospitalised patients. However, the spectrum of mild and subclinical disease has implications for population-level screening and control. Forty-nine participants were recruited from a group of 99 adults repatriated from a cruise ship with a high incidence of COVID-19. Respiratory and rectal swabs were tested by polymerase chain reaction (PCR) for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Sera were tested for anti-SARS-CoV-2 antibodies by enzyme-linked immunosorbent assay (ELISA) and microneutralisation assay. Symptoms, viral shedding and antibody response were examined. Forty-five participants (92%) were considered cases based on either positive PCR or positive ELISA for immunoglobulin G. Forty-two percent of cases were asymptomatic. Only 15% of symptomatic cases reported fever. Serial respiratory and rectal swabs were positive for 10% and 5% of participants respectively about 3 weeks after median symptom onset. Cycle threshold values were high (range 31–45). Attempts to isolate live virus were unsuccessful. The presence of symptoms was not associated with demographics, comorbidities or antibody response. In closed settings, incidence of COVID-19 could be almost double that suggested by symptom-based screening. Serology may be useful in diagnosis of mild disease and in aiding public health investigations.

Up until now, there is much debate about the role of asymptomatic patients and pauci-symptomatic patients in severe acute respiratory syndrome novel coronavirus 2 (SARS-CoV-2) transmission, and little is known about the kinetics of viral ribonucleic acid (RNA) shedding in these populations. This article aims to describe key features and the nature of asymptomatic and pauci-symptomatic SARS-CoV-2 infected patients. The cohort consisted of six participants, three pairs, which were infected with SARS-CoV-2 during February 2020 on board the Diamond Princess. Of the six confirmed (reverse transcription polymerase chain reaction [RT-PCR]) cases, four were initially diagnosed in Japan and two upon their arrival to Israel. Duration of infection was between four days and up to 26 days. Of the six patients, three were completely asymptomatic and the others were pauci-symptomatic. All five patients in whom a computerized tomography (CT) scan was performed had lung pathology. In one patient, infectivity was tested using cell culture and a cytopathic effect was demonstrated. A serology test was performed in three of the patients and all three had a positive immunoglobulin G (IgG) four to eight weeks after disease onset. This case series demonstrates that asymptomatic and pauci-symptomatic patients may play a role in infection transmission by demonstrating probable transmission among asymptomatic spouses and by demonstrating a viable virus via a cell culture. Additionally, asymptomatic and pauci-symptomatic patients can have lung pathology and developing IgG antibodies.

The objective of this study was to describe the epidemiology of COVID-19 in Nigeria with a view of generating evidence to enhance planning and response strategies. A national surveillance dataset between 27 February and 6 June 2020 was retrospectively analysed, with confirmatory testing for COVID-19 done by real-time polymerase chain reaction (RT-PCR). The primary outcomes were cumulative incidence (CI) and case fatality (CF). A total of 40 926 persons (67% of total 60 839) had complete records of RT-PCR test across 35 states and the Federal Capital Territory, 12 289 (30.0%) of whom were confirmed COVID-19 cases. Of those confirmed cases, 3467 (28.2%) had complete records of clinical outcome (alive or dead), 342 (9.9%) of which died. The overall CI and CF were 5.6 per 100 000 population and 2.8%, respectively. The highest proportion of COVID-19 cases and deaths were recorded in persons aged 31–40 years (25.5%) and 61–70 years (26.6%), respectively; and males accounted for a higher proportion of confirmed cases (65.8%) and deaths (79.0%). Sixty-six per cent of confirmed COVID-19 cases were asymptomatic at diagnosis. In conclusion, this paper has provided an insight into the early epidemiology of COVID-19 in Nigeria, which could be useful for contextualising public health planning.

Introduction: It is typical to look for UTI in delirious elderly patients, despite a high prevalence of asymptomatic bacteriuria (ASB) in this population. A common presentation of infection is delirium, which often has a non-specific and multifactorial etiology. Therefore, when bacteriuria is present with delirium in the absence of urinary symptoms, physicians prescribe antibiotics for the suspected UTI-induced delirium. We set to determine whether antibiotic treatment in the elderly presenting with delirium in the presence of ASB resulted in resolution of delirium. Methods: Literature searches were performed in MEDLINE, EMBASE, CINAHL and Cochrane Library. Abstracts were independently reviewed by two authors for decision to include for full-text review. Inclusion criteria included female gender, >65 years of age, presenting in an acute care setting with delirium and ASB. The primary outcome was resolution of delirium. The secondary outcomes were mortality, frequency of side effects from antibiotics, length of hospital stay and readmission for delirium. Results: 930 abstracts published from 1946-2017 were screened, and 42 were included for full text review. No studies were eligible for inclusion in the systematic review, as none addressed the primary outcome. One study addressed the outcomes of poor functional recovery after delirium and the rate of improvement of delirium symptoms after presentation of delirium with ASB. Conclusion: Even though current guidelines recommend against treatment of ASB, no guideline states whether ASB should be treated in elderly patients with delirium. Little evidence exists to elucidate whether treating delirious patients with ASB results in improvement in outcomes. Future studies should focus on demonstrating the relationship between resolution of delirium with antibiotic treatment. This will clarify whether delirium is a true symptom of ASB and whether treatment results in faster resolution of delirium.

Dengue has become a global problem in past few decades, with half of the world's population at risk of infection. For some countries of Asia and Latin America, severe dengue is a major cause of serious illness and even death in children. Pakistan has been reported as a hyperendemic area for dengue infection. Our study aimed to find seroprevalence of past dengue infection in asymptomatic children of Lahore with no previous history of dengue infection. A total of 400 samples were collected from children aged 1–12 years in Lahore using random sampling. The inclusion criteria were children aged 1–12 years, who had no previous symptoms of dengue fever during their lives. Children with known immunodeficiency status or fever at the time of recruitment were excluded from the study. Commercially available ELISA kits were used to determine the IgG status in sera of children. The data obtained was entered and analysed using SPSS v. 20.0. The overall prevalence of asymptomatic dengue infection was found to be 25%. There was no statistically significant difference between prevalence of infection in male and female children. There was, however, a strong relationship between increasing age of the child and number of cases with infection, with low incidence in children aged ⩽5 years.

Asymptomatic isolated congenital left ventricular diverticulum: a cardiac MRI report about a 19-year-old man.

The development of therapies for Alzheimer's disease (AD) presents numerous challenges for physicians, researchers, and the pharmaceutical industry, with many drug candidates showing promise at one stage of clinical research only to fall at the next hurdle. A great number of drugs with a variety of targets and clusters of mechanisms are currently in various stages of basic and clinical investigation. However, these hypothesis-derived agents may be tested much too late in the chronically progressive disease process to demonstrate meaningful effects or outcomes, mirroring the clinical syndromal scenario in which the underlying pathophysiological disease condition is frequently diagnosed extremely late. Moreover, the complexity of the disease calls for developments and improvements in study designs and methods modeled for different target populations and disease stages (e.g. asymptomatic to prodromal to syndromal). New integrated concepts and models of disease pathophysiology, use of validated and qualified biomarkers, outcomes and endpoints, particularly the development of a surrogate outcome, may allow targeting of characteristic mechanism-derived therapies of specifically affected biological systems at different time-points in the disease process, providing increasing opportunities for early and preventative intervention. A core set of feasible diagnostic and predictive biomarkers is already validated and in the process of standardization; however, continued and intensified research efforts will likely reveal a variety of novel biomarkers that grasp the complexity of the underlying disease process. In the future, trials of drugs to modify and prevent AD may embrace enrichment strategies and maybe be stratified by disease stage, genetic factors as well as by disease endophenotypes.

The current review was conducted to address the ongoing debate regarding the presence or absence of neuropsychological impairment in asymptomatic HIV-Type 1 (HIV-1) seropositive individuals. Results were summarized from 57 studies that compared the performances of seropositive asymptomatic and seronegative individuals. Overall, the differences observed between median rates of impairment for asymptomatic (35%) and seronegative (12%) groups provided the clearest indication of deficits in asymptomatics. In addition, five variables were examined as possible contributors to inconsistencies found in the literature: mode of infection, test battery type, test battery size, sample size, and method of data analysis. Of these variables, only mode of infection and test battery size appeared to substantially influence the outcome of the studies reviewed with regard to identifying neuropsychological impairment in asymptomatics. (JINS, 1995, I, 304–315.)

The burden and duration of asymptomatic malaria infections were measured in residents of the malaria endemic village of Gonoa, Madang Province, Papua New Guinea. Plasmodium falciparum, P. vivax and P. malariae infections in people aged 4 years to adulthood were compared. Frequent sampling at 3-day intervals for up to 61 days allowed assessment of individual episodes of infection. Statistical assessment of P. falciparum detection revealed a periodicity consistent with synchronous replication of this species over periods up to 27 days. The duration of P. falciparum episodes was longer across all age groups than that of P. vivax and P. malariae. A trend for decreasing duration with age was also noted in data from each species. This was most prominent in P. falciparum infections: median duration in 4-year-olds was > 48 days compared with a median between 9 and 15 days in older children and adults. The results are consistent with the slow acquisition of immunity to antigenically diverse Plasmodium populations and suggest a faster rate of acquisition to P. vivax and P. malariae than to P. falciparum.