Diagnosis Of Chronic Hepatitis C Virus Infection Research Articles

Implementation of a re-linkage to care strategy in patients with chronic hepatitis C who were lost to follow-up in Latin America.

To achieve WHO's goal of eliminating hepatitis C virus (HCV), innovative strategies must be designed to diagnose and treat more patients. Therefore, we aimed to describe an implementation strategy to identify patients with HCV who were lost to follow-up (LTFU) and offer them re-linkage to HCV care. We conducted an implementation study utilizing a strategy to contact patients with HCV who were not under regular follow-up in 13 countries from Latin America. Patients with HCV were identified by the international classification of diseases (ICD-9/10) or equivalent. Medical records were then reviewed to confirm the diagnosis of chronic HCV infection defined by anti-HCV+ and detectable HCV-RNA. Identified patients who were not under follow-up by a liver specialist were contacted by telephone or email, and offered a medical reevaluation. A total of 10,364 patients were classified to have HCV. After reviewing their medical charts, 1349 (13%) had undetectable HCV-RNA or were wrongly coded. Overall, 9015 (86.9%) individuals were identified with chronic HCV infection. A total of 5096 (56.5%) patients were under routine HCV care and 3919 (43.5%) had been LTFU. We were able to contact 1617 (41.3%) of the 3919 patients who were LTFU at the primary medical institution, of which 427 (26.4%) were cured at a different institutions or were dead. Of the remaining patients, 906 (76.1%) were candidates for retrieval. In our cohort, about one out of four patients with chronic HCV who were LTFU were candidates to receive treatment. This strategy has the potential to be effective, accessible and significantly impacts on the HCV care cascade.

Laboratory-based testing for hepatitis C infection using dried blood spot samples: A systematic review and meta-analysis of diagnostic accuracy.

The use of dried blood spot (DBS) samples can facilitate the implementation of reflex testing by circumventing the need for centrifugation and freezing of venous blood samples. This systematic review assessed the accuracy of using DBS samples to diagnose chronic hepatitis C virus (HCV) infection. A comprehensive search was undertaken to identify articles published up to July 2020 evaluating the diagnostic accuracy of anti-HCV, HCV-RNA and HCV core antigen tests using DBS. Screening, data extraction, quality appraisal and Grading of Recommendations, Assessment, Development and Evaluations certainty of the evidence assessment were performed independently by two reviewers. Meta-analysis, meta-regression and sensitivity analyses were conducted. The evidence demonstrates that laboratory-based anti-HCV and HCV-RNA tests using DBS samples have high diagnostic accuracy. All comparisons were between DBS and venous samples. For the detection of anti-HCV, sensitivity was 95% (95% CI: 92%-97%) and specificity was 99% ([95% CI: 98%-99%]; n=25; I2 =81%; moderate certainty). For the detection of HCV-RNA, the sensitivity was 95% (95% CI: 93%-97%) and specificity was 97% ([95% CI: 94%-98%]; n=20; I2 =52%; moderate certainty). The sensitivity of HCV core antigen tests was 86% (95% CI: 79%-91%) and specificity was 98% ([95% CI: 94%-99%]; n=5; I2 =37%; low certainty) compared with HCV-RNA (the gold standard for detecting chronic HCV). DBS samples could facilitate diagnosis of chronic HCV infection as the necessary sequential tests (anti-HCV and then HCV-RNA or HCV core antigen) can be undertaken using the same blood sample. This could reduce loss of patient follow-up and support international efforts towards HCV elimination in both high and low prevalence settings.

Disparities in Cirrhosis Management of Black Patients: Do We Know What to Address?

Disparities in Cirrhosis Management of Black Patients: Do We Know What to Address?

Laboratory-based dried blood spot testing for hepatitis C: A protocol for systematic review and meta-analysis of diagnostic accuracy

Background: Diagnosis of chronic hepatitis C virus (HCV) infection typically involves collection of venous blood samples prior to serological investigation of an antibody response followed by a confirmatory viral load or antigen test to verify active HCV infection. This conventional pathway poses logistical challenges for the implementation of reflex testing, whereby the confirmatory test is performed on the same sample used for serological investigation. Dried blood spot (DBS) testing, in which capillary blood is deposited on filter paper, is a less invasive alternative that can enable reflex testing without the need for venepuncture, centrifugation and freezing of samples. Methods: This systematic review aims to assess the diagnostic accuracy of DBS compared with venous blood samples for diagnosis of chronic HCV infection. Observational studies which compare diagnostic tests using DBS with those using serum, plasma or whole blood in patients with chronic or resolved HCV infection will be included. Electronic searches will be conducted in PubMed, Embase, Scopus, Web of Science, Lilacs and the Cochrane library. Citation screening, data extraction and quality appraisal of included studies will be performed in duplicate using the Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2) tool. A meta-analysis will be conducted to derive pooled estimates of sensitivity, specificity, positive likelihood ratios, negative likelihood ratios, and diagnostic odds ratios. Sensitivity analyses and meta-regression will also be performed. Quality of the evidence will be evaluated using the GRADE criteria. Discussion: Identifying and linking people with currently undiagnosed chronic HCV infection to care is pivotal to attaining global viral hepatitis elimination targets. The use of DBS could simplify diagnostic testing strategies by integrating reflex testing into the care pathway and reducing drop-off along the cascade of care. Registration: PROSPERO, CRD42020205204. Registered 19 th September 2020.

Laboratory-based dried blood spot testing for hepatitis C: A protocol for systematic review and meta-analysis of diagnostic accuracy.

Background: Diagnosis of chronic hepatitis C virus (HCV) infection typically involves collection of venous blood samples prior to serological investigation of an antibody response followed by a confirmatory viral load or antigen test to verify active HCV infection. This conventional pathway poses logistical challenges for the implementation of reflex testing, whereby the confirmatory test is performed on the same sample used for serological investigation. Dried blood spot (DBS) testing, in which capillary blood is deposited on filter paper, is a less invasive alternative that can enable reflex testing without the need for venepuncture, centrifugation and freezing of samples. Methods: This systematic review aims to assess the diagnostic accuracy of DBS compared with venous blood samples for diagnosis of chronic HCV infection. Observational studies which compare diagnostic tests using DBS with those using serum, plasma or whole blood in patients with chronic or resolved HCV infection will be included. Electronic searches will be conducted in PubMed, Embase, Scopus, Web of Science, Lilacs and the Cochrane library. Citation screening, data extraction and quality appraisal of included studies will be performed in duplicate using the Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2) tool. A meta-analysis will be conducted to derive pooled estimates of sensitivity, specificity, positive likelihood ratios, negative likelihood ratios, and diagnostic odds ratios. Sensitivity analyses and meta-regression will also be performed. Quality of the evidence will be evaluated using the GRADE criteria. Discussion: Identifying and linking people with currently undiagnosed chronic HCV infection to care is pivotal to attaining global viral hepatitis elimination targets. The use of DBS could simplify diagnostic testing strategies by integrating reflex testing into the care pathway and reducing drop-off along the cascade of care. Registration: PROSPERO, CRD42020205204. Registered 19 th September 2020.

A Patient Decision Support Tool for Hepatitis C Virus and CKD Treatment

Rationale & ObjectivePatient education and decision support tools could facilitate decisions around the timing of antiviral therapy in patients living with both hepatitis C virus (HCV) infection and chronic kidney disease (CKD). We previously developed a tool through the HELP (Helping Empower Liver and Kidney Patients) study. This article evaluates the preliminary efficacy and usability of the tool among participants with both HCV infection and CKD.Study DesignPre-post study pilot evaluation.Setting & ParticipantsParticipants were at least 18 years old, were English speaking, and had a diagnosis of chronic HCV infection and CKD; they were seen in CKD clinics, dialysis units, and/or hepatology and liver transplantation clinics.InterventionElectronic patient decision support tool.OutcomesParticipants’ change in knowledge, certainty about choice, decision self-efficacy, patients’ treatment preferences, and tool usability.Results70 participants were recruited; 56 of 70 (80.0%) completed study procedures. Nearly all (51/56; 91.1%) requested paper-based study procedures despite the electronic design of the tool. Participants reported that they were most worried about the following treatment factors: (1) cost of drugs to treat HCV infection, (2) how their HCV infection affected their CKD, and (3) wait times for a kidney transplant. After using the decision tool, participants had significantly higher HCV infection and CKD knowledge (mean posttest percent of questions answered correctly = 65.74% vs pretest percent of questions answered correctly = 53.44%; P < 0.001) and more certainty about choice (mean posttest = 3.13 vs pretest = 2.65; P = 0.05). There were no significant changes in decision self-efficacy (mean posttest = 86.62 vs pretest = 84.68; P = 0.48).LimitationsSingle-site pilot study to explore preliminary tool efficacy and usability.ConclusionsThis study suggests that a decision tool may support informed patient-centered choices among patients with HCV infection and CKD. Future studies should evaluate ways to improve care decisions in a larger sample using both paper-based and electronic materials.FundingMerck & Co, Inc, Kenilworth, NJ.Trial RegistrationRegistered at clinicaltrials.gov with study number NCT03426787.

Diagnosis and monitoring of HCV infection using the cobas® HCV test for use on the cobas® 6800/8800 systems

Background and objectivesAccurate, sensitive, and specific tests for detection and monitoring of hepatitis C virus (HCV) RNA concentrations are essential for diagnosis and management of HCV infections. We evaluated the next-generation reverse-transcription real-time PCR test, cobas® HCV test for use with the cobas® 6800/8800 systems (“cobas HCV”) by determining its analytical performance characteristics and clinical utility for the diagnosis and therapeutic monitoring of chronic HCV infections. MethodsThe limit of detection (LOD), linearity, precision, specificity, matrix equivalence of plasma and serum, and quantitative agreement with the COBAS® AmpliPrep/COBAS® TaqMan® HCV Test version 2.0 (“CAP/CTM HCV v2”) were evaluated. Clinical utility for the diagnosis of chronic HCV infection was demonstrated by testing plasma from HCV seropositive individuals and comparing results to a nucleic acid amplification test (NAAT) approved for use in the diagnosis of chronic hepatitis C. Clinical specificity was investigated by testing plasma from HCV antibody negative subjects with non-HCV related liver diseases. Utility for monitoring treatment response was defined by testing plasma collected during treatment of HCV genotypes (GT) 1, 2, and 3 and determining positive predictive value (PPV), negative predictive value (NPV) and the odds ratio (OR) for predicting cure (sustained virologic response 12 weeks after treatment cessation, “SVR12”). ResultsThe cobas HCV test demonstrated an LOD of at least 15 IU/mL and measurable range from 15 to at least 1.0E + 08 IU/mL (1.2–8.0 log10 IU/mL) for GT 1–6, with high accuracy (≤0.16 log10 difference) and precision (standard deviation 0.04–0.14 log10) throughout the linear range. Paired plasma and serum samples showed highly correlated performance (R2 = 0.97). Quantification was 100% specific for HCV in analytical studies. Correlation with CAP/CTM HCV v2 was high in patient samples (mean titer difference: 0.05 log10 with a 95% CI: 0.03–0.06 log10). For the diagnosis of chronic HCV, positive and negative percent agreement between cobas HCV and the comparator NAAT were 98.8–100% on the cobas 6800 and 8800 systems. Clinical specificity of cobas HCV using samples from HCV antibody negative subjects with non-HCV related liver diseases was 99.6% and 100% on cobas 6800 and 8800 systems. In therapeutic monitoring and SVR12 prediction during experimental treatment for chronic HCV GT 1 infections, undetectable HCV RNA by cobas HCV at different on-treatment weeks had a PPV 76.8%–79.4%, NPV 29.9%–100%, and OR 1.64–47.52. During therapy of HCV GT 2 and GT 3, treatment week 4 and 12 results were: PPV, 84.7% and 75.3%; NPV, 47.8% and 50.0%; OR, 5.09 and 3.05. ConclusionsThe cobas HCV test is highly sensitive, specific, and accurate HCV RNA test for GT 1–6. It demonstrates excellent correlation with the FDA-approved CAP/CTM HCV v2 test. It is useful clinically for detection of active HCV infection in individuals that have had a positive anti-HCV antibody test result and in monitoring treatment response.

The Predictive Value of International Classification of Disease Codes for Chronic Hepatitis C Virus Infection Surveillance: The Utility and Limitations of Electronic Health Records.

Surveillance of chronic hepatitis C virus (HCV) cases faces limitations that result in delays and under-reporting. With increasing use of electronic health records (EHRs), the authors evaluated the predictive value of using International Classification of Diseases, Ninth Revision (ICD-9) codes to identify chronic HCV cases from EHR data. Longitudinal EHR data from 4 health care systems during 2006-2012 were evaluated. Using chart abstraction and review to confirm chronic HCV cases ("gold standard" definition), the authors calculated the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of 2 case definitions: (1) ≥2 ICD-9 codes separated by ≥6 months and (2) ≥1 positive HCV RNA (ribonucleic acid) test. Among 2,718,995 patients, 20,779 (0.8%) with ICD-9 codes indicating a likely diagnosis of chronic HCV infection were identified; 13,595 (65.4%) of these were randomly selected for review. Case definition 1 (≥2 ICD-9 codes separated by ≥6 months) had 70.3% sensitivity, 91.9% PPV, 99.9% specificity, and 99.9% NPV while case definition 2 (≥1 positive HCV RNA test) had 74.1% sensitivity, 97.4% PPV, 99.9% specificity, and 99.9% NPV. The predictive values of these alternate EHR-derived ICD-9 code-based case definitions suggest that these measures may be useful in capturing the burden of diagnosed chronic HCV infections. Their use can augment current chronic HCV case surveillance efforts; however, their accuracy may vary by length of observation and completeness of EHR data.

How Current Direct-Acting Antiviral and Novel Cell Culture Systems for HCV are Shaping Therapy and Molecular Diagnosis of Chronic HCV Infection?

We have entered a new era of hepatitis C virus (HCV) therapy in which elimination of infection and disease is a real possibility. HCV cell culture models were instrumental for identification of therapeutic targets, testing candidate drugs, and profiling of therapeutic strategies. Here we describe current and novel methods of cell culture systems for HCV that are allowing investigation of HCV life cycle and virus-host interaction required for replication and propagation. The development of protocols to grow infectious virus in culture and generate hepatocyte cell lines from specific individuals hold great promise to investigate the mechanisms exploited by the virus to spread the infection and the host factors critical for HCV replication and propagation, or resistance to infection. Since host factors are presumably conserved and equally interacting with different HCV isolates and genotypes, the development of drugs targeting host factors essential for virus replication holds great promises in further increasing treatment efficacy. Refocusing of therapeutic goals also impacted in vitro diagnosis. The primary goal of anti-HCV therapy is to achieve a sustained virologic response (SVR) defined as "undetectable" HCV RNA genome in the serum or plasma at 12 to 24 weeks following the end of treatment. Use of direct antiviral agents has substantially changed the threshold of the viral load used to define SVR and led to a reassessment, as discussed herein, of result interpretation and requirements of clinically-approved, quantitative molecular assays.

Extrahepatic manifestations of chronic hepatitis C virus infection: 297 cases from a tertiary medical center in Beijing, China

Background Chronic hepatitis C virus (HCV) infection can affect multiple organ systems and cause a variety of extrahepatic manifestations (EMs). We sought to assess the constituent ratio of EMs in Chinese patients with chronic HCV infection and identify the clinical and biological factors associated with EM. Methods The medical records of 297 patients with chronic HCV infection were analyzed and demographic and epidemiological information was collected. The diagnosis of chronic HCV infection was based on positive anti-HCV combined with a positive HCV-RNA or at least two times of elevated aminotransferases attributable to HCV infection. Patients with HBV and/or HIV coinfection, autoimmune hepatitis, and history of alcohol abuse were excluded. Results Sixty-two percent (184/297) of the patients had at least one EM, including fatigue (29.4%), type 2 diabetes mellitus (28.2%), renal involvement (12.5%), lymphadenopathy (9.6%), fever (9.4%), thyroid dysfunction (8.1%), and arthralgia (7.4%). Neuropathy, sicca syndrome, B-cell lymphoma, Raynaud's phenomenon, and lichen planus were rare. The mean age of patients with EM was older compared with those without EM. Conclusions EMs were common in Chinese patients with chronic HCV infection, particularly fatigue, type 2 diabetes, renal impairment, lymphadenophy, fever, and thyroid dysfunction. Older age was associated with EMs.

Sustained Virologic Response After 6 Weeks of Therapy With a First-Generation Hepatitis C Virus Protease Inhibitor

To the Editor—Patients with hepatitis C virus (HCV) genotype 1 infection should receive 12 weeks of triple combination therapy with the first-generation HCV protease inhibitor telaprevir, pegylated interferon (peg-IFN) alfa-2a or alfa-2b, and ribavirin (RBV), followed by 12 or 36 weeks of double therapy with peg-IFN and RBV [1]. We report a case of sustained virologic response (SVR) achieved after only 6 weeks of triple combination treatment. A 53-year-old white woman with history of breast cancer was treated with surgery, adjuvant chemotherapy, and radiation in 2010, followed by hormonal therapy with letrozole. During a routine follow-up at another facility, elevated transaminases were detected and further investigation led to the diagnosis of chronic HCV infection that was probably acquired 30 years before current presentation. She was infected with HCV genotype 1b, and host genotyping revealed the IL28B CC allele. Liver biopsy showed bridging fibrosis. The patient was initiated on telaprevir, peg-IFN alfa-2a, and RBV. Concurrent medications included hydrochlorothiazide and lisinopril for hypertension. Letrozole was discontinued a few weeks before antiviral treatment initiation, to avoid potential drug interactions. On week 4 of treatment, the HCV load was undetectable (rapid virological response [RVR]). Two weeks later, the patient presented with shortness of breath, anemia, thrombocytopenia, rash, and acute renal failure. HCV treatment was discontinued because of severe renal dysfunction. During the first 2 weeks off therapy, the hematologic toxic effects worsened, necessitating hospital admission, use of hematopoietic growth factors, and red blood cell transfusion (Figure ​(Figure11). Figure 1. Outcome and laboratory abnormalities in a patient successfully treated with 6 weeks of telaprevir-based therapy. aHepatitis C virus was measured with the transcription-mediated amplification method. Abbreviations: HCV, hepatitis C virus; Rx, treatment; ... The patient was referred to our institution for investigation of possible myelodysplastic syndrome. Bone marrow biopsy revealed no evidence of malignancy, and the abnormal laboratory parameters were attributed to HCV treatment. In the following weeks, the patient improved and all laboratory parameters normalized. The HCV load remained undetectable at 24 weeks after cessation of HCV treatment (SVR24). Telaprevir-containing therapy is very effective, but is often associated with the development of severe side effects [1]. This treatment combination is also associated with renal impairment, which leads to more pronounced anemia from decreased RBV elimination [2]. The half-life of RBV ranges from 100 hours normally to 500 hours in patients with decreased renal function [3]. The renal impairment our patient developed might have contributed to her severe anemia by prolonging RBV exposure after treatment cessation. The fact that the anemia worsened even after treatment discontinuation supports this hypothesis. On the other hand, extended RBV exposure might have led to the patient's favorable virologic outcome. In regard to positive predictors of response to HCV treatment, our patient had several: female sex, white race, HCV-1b genotype infection, IL28B CC allele, low baseline viral load, no cirrhosis or steatosis, and RVR [4]. We found 2 reports of patients with SVR after shortened duration of telaprevir-based therapy (Table ​(Table1)1) [5, 6]. The common characteristics of these patients and our patient include non–African American race, HCV-1b genotype, and absence of cirrhosis. Table 1. Reported Cases of Sustained Virologic Response After Short-Duration Telaprevir-Based Therapy The interim analysis of an exploratory multicenter study designed to evaluate the efficacy of 12-week-total telaprevir-based therapy in patients with HCV genotype 1, either treatment-naive or with relapse after treatment, showed an SVR of 87% (74 of 85 subjects) among noncirrhotic patients with the IL28B CC genotype who had achieved RVR [7]. In conclusion, the addition of first-generation protease inhibitors to the anti-HCV treatment armamentarium has improved outcomes of patients infected with genotype 1 HCV [1]. Unfortunately, these regimens are frequently associated with serious adverse events. The present report describes the common characteristics of patients successfully treated after short-duration telaprevir-based therapy.

Addition of pentoxifylline to pegylated interferon-alpha-2a and ribavirin improves sustained virological response to chronic hepatitis C virus: a randomized clinical trial

Background and aim. The commonly accepted treatment for hepatitis C virus (HCV) infection, pegylated interferon alpha (PEG INF-alpha) and ribavirin, leads to 50–60% of sustained virological response (SVR). On the other hand, pentoxifylline (PTX) possesses antiviral and hepatoprotector properties. Aim. To investigate whether the addition of PTX to conventional hepatitis C treatment increases SVR.Material and methods. Seventy two patients of both genders were studied in a randomized fashion; the diagnosis of chronic HCV infection was made according to clinical and laboratory criteria and histopathologically classified according to METAVIR scoring system criteria. HCV viral load was tested by PCR, baseline, and after 6 months of treatment, as well as anti-HCV, anti-hepatitis B virus, and anti-human immunodeficiency virus antibodies by enzyme-linked immunosorbent assay. During 48 weeks, control group patients were treated with PEG INF-alpha-2a plus ribavirin. PTX was administered to Experimental Group patients prior to the treatment.Results. Demographic data were similar in both groups. Experimental- and control-group subjects were at F2 and F3 states according to the METAVIR classification. The most common HCV genotypes were 1a and 1b (39% in the control group in each case, and 42% in the experimental group in each case). At the end of the study, hepatic enzymes and viral load decreased in both groups to similar values. SVR in the experimental group increased significantly (p < 0.05) when compared with standard therapy alone.Conclusion. Addition of PTX to conventional chronic hepatitis C treatment may increase the percentage of patients with SVR.

Evaluation of core and NS4B synthetic peptide-based immunoassays for the detection of hepatitis C virus antibodies in clinical samples from Cameroon, Central Africa

Background According to previous data, the antibodies produced during natural hepatitis C virus (HCV) infection frequently recognize amino acids 10–43 in the core protein and 1689–1740 or 1921–1940 in the non-structural 4B (NS4B) protein. The reactivity of these peptides with the corresponding antibodies has mainly been evaluated using serum samples from Western countries where HCV genotype 1 (HCV-1) is predominant, and no information is available concerning samples from sub-Saharan countries where high HCV variability has been reported. Objective of this study To evaluate the performance of HCV core and NS4B peptide-based immunoassays in the serodiagnosis of HCV infection in Cameroon subjects. Study design Three core and four NS4B-based synthetic peptides derived from HCV genotypes 1b and 2a were designed and tested against a panel of 151 serum samples from Cameroon (40 positive for HCV-1, 32 for HCV-2, 39 HCV-4, and 40 HCV-negative). Results The three core peptides all demonstrated strong immunoreactivity, regardless of the HCV genotype from which they were derived, with greater than 90% and 92% sensitivity and specificity. In contrast, the NS4B-derived peptides exhibited lower sensitivities (24.3–65.8% depending on the HCV genotype) but higher specificities (100% for all four peptides tested). Conclusions Our findings indicate that an HCV core peptide could be used for the diagnosis of chronic HCV infection. Among the NS4B peptides tested, a chimeric NS4B peptide encompassing both N- and C-terminal portions of the NS4B protein gave a much better performance than the two component N- and C-terminal peptides used individually.

Prevalence and genotyping of hepatitis C virus in blood donors in the state of Pará, Northern Brazil

Given the scarcity of epidemiological information on hepatitis C virus (HCV) infection in Northern Brazil, we determined the prevalence and genotypic frequency in blood donors in the state of Pará (PA). Blood samples from all of the blood donors at the Fundação HEMOPA (blood bank of PA) from 2004-2006 were screened for the presence of antibodies to anti-HCV and samples seroreactive to anti-HCV were further tested for HCV RNA using real-time PCR. In total, 116 HCV-RNA samples were genotyped, based on maximum likelihood phylogenetic analyses, using BioEdit, Modelgenerator, PHYML and FigTree software. The population consisted of 242,726 volunteers who donated blood from 2004-2006; the most common subgroup was males between the ages of 18-29 years old (37.30%). Within the whole group, 1,112 blood donors (0.46%) had indeterminate or positive serology; among these, 28.78% were males whose ages ranged from 18-29 years. A diagnosis of chronic HCV infection was confirmed for 304 donors (60.20% males; 66.45% were 30-49 years old), resulting in a prevalence of HCV RNA in 0.13% of the samples (304 of 242,726). HCV genotyping revealed a high frequency of genotype 1 (108/116) followed by genotype 3 (8/116). This study found HCV infection to be relatively infrequent in PA; genotype 1 was most commonly isolated. This information can help guide prevention and control policies aimed at efficient diagnosis and control measures.