Detection Of Clinical Cases Research Articles

Detection of Hepatovirus A (HAV) in wastewater indicates widespread national distribution and association with socioeconomic indicators of vulnerability.

Wastewater-based epidemiology, which seeks to assess disease occurrence in communities through measurements of infectious disease biomarkers in wastewater, may represent a valuable tool for understanding the occurrence of hepatitis A infections in communities. In this study, we measured concentrations of Hepatovirus A (HAV) RNA, in samples from 191 wastewater treatment plants spanning 40 US states and the District of Columbia from September 2023 to June 2024 and compared the measurements with traditional measures of disease occurrence. Nationally, 13.76% of the 21,079 wastewater samples were positive for HAV RNA, and both concentrations and positivity rates were associated with NNDSS hepatitis A case data nationally (Kendall rank correlation coefficient = 0.20, concentrations; and 0.33, positivity rate; both P < 0.05). We further demonstrated that higher rates of wastewater HAV detection were positively associated with socioeconomic indicators of vulnerability including homelessness and drug overdose deaths (both P < 0.0001). Areas with above average levels of homelessness were 48% more likely to have HAV wastewater detections, while areas with above average levels of drug overdose deaths were 14% more likely to have HAV wastewater detections. Using more granular case data, we present a case study in the state of Maine that reinforces these results and suggests a potential lead time for wastewater over clinical case detection and exposure events. The ability to detect HAV RNA in wastewater before clinical cases emerge could allow public health officials to implement targeted interventions like vaccination campaigns.IMPORTANCEDespite the existence of a highly effective vaccine for hepatitis A, outbreaks in vulnerable populations remain common. The disease can be asymptomatic or subclinical, and disproportionately impacts populations with inadequate access to healthcare, leading to a severe underestimation of the occurrence of this viral infection. This study investigates the potential for wastewater measurements of biomarkers of the causative agent of hepatitis A (HAV RNA) to provide insights into disease occurrence. Results highlight the potential for wastewater-based epidemiology to be a complementary tool to traditional surveillance for monitoring and controlling HAV transmission.

Bayesian sequential approach to monitor COVID-19 variants through test positivity rate from wastewater.

Deployment of clinical testing on a massive scale was an essential control measure for curtailing the burden of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections and the magnitude of the COVID-19 (coronavirus disease 2019) pandemic during its waves. As the pandemic progressed, new preventive and surveillance mechanisms emerged. Implementation of vaccine programs, wastewater (WW) surveillance, and at-home COVID-19 antigen tests reduced the demand for mass SARS-CoV-2 testing. Unfortunately, reductions in testing and test reporting rates also reduced the availability of public health data to support decision-making. This paper proposes a sequential Bayesian approach to estimate the COVID-19 test positivity rate (TPR) using SARS-CoV-2 RNA concentrations measured in WW through an adaptive scheme incorporating changes in virus dynamics. The proposed modeling framework was applied to WW surveillance data from two WW treatment plants in California; the City of Davis and the University of California, Davis campus. TPR estimates are used to compute thresholds for WW data using the Centers for Disease Control and Prevention thresholds for low (<5% TPR), moderate (5%-8% TPR), substantial (8%-10% TPR), and high (>10% TPR) transmission. The effective reproductive number estimates are calculated using TPR estimates from the WW data. This approach provides insights into the dynamics of the virus evolution and an analytical framework that combines different data sources to continue monitoring COVID-19 trends. These results can provide public health guidance to reduce the burden of future outbreaks as new variants continue to emerge. IMPORTANCE We propose a statistical model to correlate WW with TPR to monitor COVID-19 trends and to help overcome the limitations of relying only on clinical case detection. We pose an adaptive scheme to model the nonautonomous nature of the prolonged COVID-19 pandemic. The TPR is modeled through a Bayesian sequential approach with a beta regression model using SARS-CoV-2 RNA concentrations measured in WW as a covariable. The resulting model allows us to compute TPR based on WW measurements and incorporates changes in viral transmission dynamics through an adaptive scheme.

SARS-CoV-2 Wastewater Based Epidemiology in Low and Lower Middle-Income Countries: A Systematic Review

BACKGROUND AND AIM: Wastewater based epidemiology (WBE) is a promising tool to monitor the prevalence of COVID-19 disease at community level through detection of SARS-CoV-2 RNA in wastewater. Although WBE has been largely adopted in developed countries as complementary to clinical surveillance, the approach is still not widely applied in low-and-lower-middle-income countries (LMICs) owing to number of drawbacks. Despite these limitations, a small number of studies on wastewater based epidemiology for SARS-CoV-2 detection have been conducted in LMICs. The current systematic review provides an overview of the efficacy of WBE in LMICs. METHODS: We conducted keyword searches in PubMed, Web of Science, and Scopus for articles published between January 2020 to February 2022. A total of 2,057 relevant articles were identified, and 21 met our inclusion/exclusion criteria. RESULTS: The most common analytical steps used in included studies are sampling, storage, concentration, extraction, and detection. Studies utilized either composite/grab raw sludge or influents mostly from wastewater treatment plants, which covered a population of one to ten million. Among the studies, Among the studies, the most commonly used concentration technique was Poly Ethylene Glycol (PEG), and the most frequently targeted gene was the N gene. The overall sample positivity was found 81.18%, with viral loads of 40 to 45,000 copies/L. Most of the studies found positive correlation between SARS-CoV-2 viral loads in wastewater and the detected COVID-19 cases. Besides, few studies found higher signals in wastewater with a time lag of one to two weeks before clinical case detection. CONCLUSIONS: These findings of systematic review illustrate the analytical methods used in WBE research, as well as the future of WBE in LMICs, thereby allowing decision-makers to take strategic preventative actions to curb the spread of COVID-19 diseases in LMICs.

Diagnostic utility of PCR in detection of clinical cases and carriers of leprosy: A cross sectional study at a tertiary care teaching hospital in central India

PurposeSince ancient era leprosy is existing across the world. India, Indonesia and Brazil still harbour major proportion of global cases. Child leprosy and Grade II disability indicate delayed diagnosis and persistence of transmission in community. So, this study was conducted with aim to evaluate the diagnostic efficacy of PCR in comparison to SSS (Slit Skin Smear) microscopy for detection of leprosy in early stages in both cases and carriers (contacts). MethodsA cross sectional observational study was conducted on 100 subjects including 50 clinically diagnosed new cases of leprosy and their 50 contacts. Each group was subjected to SSS (Slit Skin Smear) microscopy and PCR using RLEP gene as target. ResultsThe overall male: female ratio was 2.44. The Slit Skin smear (SSS) microscopy positivity was 34% (n = 17/50) among cases while it was 0% (n = 0/50) among contacts. The overall positivity for PCR was 42% (n = 42/100) being 66% (n = 33/50) in cases and 18% (n = 9/50) in contacts. About 30% (n = 25/83) of all the microscopically negative subjects were found to be positive by PCR. ConclusionsPCR was found to be a better diagnostic tool both among cases and their contacts. It should be used for screening contacts for early diagnosis and treatment and thus preventing transmission in community. Key messageTo diagnose case and contacts of leprosy in early stages even in very low bacterial density using PCR.

A national serosurvey to determine the prevalence of paratuberculosis in cattle in Bhutan following detection of clinical cases.

Johne's disease is an economically important ruminant disease predominantly affecting cattle, sheep and goats. The economic losses are due to early culling, reduced growth rate, progressive weight loss and reduced production. It is caused by Mycobacterium avium subspecies paratuberculosis (MAP). Johne's disease was reported in cattle in Bhutan, based on clinical signs and histopathology; in the late 1990s samples from one mithun that was suspected to have died due to this disease was confirmed by molecular testing at the Faculty of Veterinary Science, University of Sydney, Australia. However, no detailed study on prevalence of JD has been attempted in Bhutan. Objective of this study was to conduct serosurveillance to determine the national prevalence of Johne's disease in cattle for the period 2013–2014 to provide the basis for planning a future control strategy. A national serosurvey was conducted wherein a two‐stage sampling procedure was used with 95% confidence and an error level of ±0.05. The sample size required for the survey was calculated using the software‐Survey Toolbox for Livestock Diseases, available as Epitools at http://www.ausvet.com.au. A total of 1123 serum samples were collected from an administrative structure of 52 villages, 40 sub‐districts and 15 districts. Serum samples were tested using commercially available antibody enzyme linked immunosorbent assay. Statistical analysis was performed using GraphPad Prism 5.0. Illustration such as maps was produced using QGIS version 2.18 ‘Las Palmas. The mean national apparent prevalence of Johne's disease was found to be 2.31 (26/1123) (95% CI: 0.80–4.50) with an estimated true prevalence was found to be 8.00 (95% CI: 2.00–17.00). Trongsa district had the highest prevalence (12.96) followed by Zhemgang (4.34), Lhuntse (4.25), Sarpang (3.89), Bumthang (3.60), Trashigang (2.67) and Haa (2.63). Prevalence for all other districts was 2.00 or below. Seropositive samples were reported from all over the country with varying levels of sero‐positivity. In the recent past many more cattle were imported from India to boost dairy production. Nevertheless, the wide distribution of seroreactive JD cattle all over the country is a concern for future control. Therefore, in future, a detailed study on the impact of cattle import with regard to disease incursion such as Johne's disease and other diseases should be undertaken.

Does the Transcontinental Escalation of Zika Virus Infection Pose a Major Global Threat to Human Health and are Current Public and Media Concern Justified?

The Zika virus is transmitted between humans primarily by the infectious bite of the Aedes aegypti and A. albopictus species of daytime-feeding mosquito. The infection so caused emerged explosively in South America 18 months ago, with the primary impact of thousands of babies born with microcephaly, a serious neurological defect. Although the epidemic that was centred initially in Brazil has since spread throughout Latin America, the rate of its progress to other regions of the globe has not been as rapid as was first predicted. This has enabled the public health surveillance systems in countries in North America, Europe and the Asia Pacific region to be placed on high alert for the detection of clinical cases in, for instance, travellers returning from known Zika-endemic zones. This has contributed to reducing the likely future impact of Zika on regions that are not currently affected. This should act to dampen the media frenzy that accompanied preparation for the recent Rio de Janeiro Olympic and Paralympic Games concerning not only the local impact but the threat of a global pandemic. However, a significant caveat is that the geographical distribution of vector mosquitoes may be modified by climate change, with an incrementally increasing range; this should be monitored assiduously in order to prepare for the risk of local outbreaks in areas previously free of infection. It should be stressed that in developing countries situated in tropical and subtropical climates, where public health provision is not as well-established as in industrialised nations, there may remain a significant threat of Zika epidemics for years to come. On a positive note, a unified vector control and prevention strategy can encompass Zika and the closely related yellow fever, dengue and chikungunya arboviruses, which are all carried by the same Aedes mosquitoes. Thus, such a ‘one size fits all’ approach may help to combat the cause of several major tropical infectious diseases.

Clinical characteristics and treatment outcomes of tuberculosis cases hospitalised in the intensive phase in Fiji.

Tuberculosis (TB) is an ongoing public health challenge in Fiji. Clinical case detection and management are critical for effective TB control. Most TB cases in Fiji are hospitalised for the intensive phase of treatment. To describe the demographic and clinical characteristics, comorbidities and final treatment outcomes of TB patients hospitalised for the intensive phase of treatment in Fiji. A retrospective, descriptive study of all TB cases hospitalised during the intensive phase over a 3-year period (2010-2012). A total of 395 TB hospitalised cases were included, of whom 61% were sputum smear-positive. The largest proportions of cases were among young adults (15-34 years) and the unemployed, respectively 43% and 71%. Diabetes (13%) and smoking (22%) were common comorbidities. Final anti-tuberculosis treatment outcomes were available for 96% of cases; 81% were cured or completed treatment. Default was more common in those with current employment. Death was the final treatment outcome in 4%, and was more common (11%) in the oldest group aged 355 years (OR 5.7, 95%CI 1.9-17). This study provides original and comprehensive descriptive data on TB cases in Fiji and identifies characteristics associated with poor treatment outcomes.

Relationship between clinical signs and transmission of an infectious disease and the implications for control.

Control of many infectious diseases relies on the detection of clinical cases and the isolation, removal, or treatment of cases and their contacts. The success of such "reactive" strategies is influenced by the fraction of transmission occurring before signs appear. We performed experimental studies of foot-and-mouth disease transmission in cattle and estimated this fraction at less than half the value expected from detecting virus in body fluids, the standard proxy measure of infectiousness. This is because the infectious period is shorter (mean 1.7 days) than currently realized, and animals are not infectious until, on average, 0.5 days after clinical signs appear. These results imply that controversial preemptive control measures may be unnecessary; instead, efforts should be directed at early detection of infection and rapid intervention.

P29.36 MRSA clinical case detection is more accurate than MRSA bacteraemia rates for detecting the effect of control measures

P29.36 MRSA clinical case detection is more accurate than MRSA bacteraemia rates for detecting the effect of control measures

Clonal analysis of the serogroup B meningococci causing New Zealand's epidemic

An epidemic of meningococcal disease caused by serogroup B meningococci expressing the P1.7-2,4 PorA protein began in New Zealand in 1991. The PorA type has remained stable. Different porB have been found in association with the P1.7-2,4 PorA, although type 4 has been most common. The clonal origins of B:P1.7-2,4 meningococci isolated from cases during 1990 to the end of 2003 were analysed. In 1990, the year immediately preceding the recognized increase in disease rates, all three subclones (ST-41, ST-42, and ST-154) of the ST-41/44 clonal complex occurred among the five isolates of B:P1.7-2,4. The two sequence types, ST-42 and ST-154, continued to cause most disease throughout New Zealand. Isolates belonging to subclone ST-41 were mostly identified early in the epidemic and in the South Island. 16S rRNA typing indicated that isolates belonging to the subclones ST-41 and ST-154 share a common ancestor, with those typing as ST-42 more distantly related with some genetically ambiguous. It is possible that ST-41 and ST-154 may have evolved one from the other but evolution to ST-42 is more difficult to explain. It is possible that one or more of the ST types could have been introduced into New Zealand prior to the first detection of clinical cases in 1990. Genetic diversity may have occurred during carriage in the community.

Detection of antibodies to Plasmodium vivax by indirect immunofluorescence: influence of the geographic origin of antigens and serum samples.

The results of a double-blind serological study of 15 sera sampled in a residual focus of vivax malaria transmission in Algeria, and of 7 sera from patients with slide-proven P. vivax infections acquired in India, are analyzed. The reactivity of each of these serum samples was tested by indirect immunofluorescence using 6 different batches of antigen, including 3 batches of P. vivax antigen prepared with isolates from Zaire (Africa), India and the Solomon Islands, respectively. The geometric mean of reciprocal titers (GMRT) calculated on the 7 sera from proven vivax infections fell from 289.8 using the homologous antigen from the same geographic origin (India) to 48.7 using a homologous (vivax) antigen originating from a different continent (Africa). Among the 15 samples from Algeria, the percentage of seropositives decreased from 100% using the homologous P. vivax antigen originating from the same continent (Africa) to 53.3% using a homologous antigen from India. Two aspects are included in the discussion: in seroepidemiological studies, sensitivity could be improved by the use of a homologous antigen from the same geographic origin; in detection of clinical cases of malaria and species identification based on serology, our results stress the need for caution in interpreting serological titers and for taking into account the geographic origin of the isolates used as antigen.