Diagnosis of West Nile virus infections:Evaluation of different laboratory methods

BACKGROUND The diagnosis of West Nile virus(WNV)is challenging due to short-term and low-level viremia,flavivirus cross-reactivity,and long immunoglobulin M(IgM)persistence.AIM To evaluate different methods for WNV detection[reverse transcription-polymerase chain reaction(RT-PCR),IgM/IgG antibodies,IgG avidity]in serum,cerebrospinal fluid(CSF),and urine samples of patients with confirmed WNV infection.METHODS The study included patients with confirmed WNV neuroinvasive infection(n=62),asymptomatic WNV seropositive individuals(n=22),and individuals with false-positive WNV IgM antibodies(n=30).WNV RNA was detected using RT-PCR.A commercial ELISA was used to detect WNV IgM/IgG antibodies with confirmation of cross-reactive samples using a virus neutralization test(VNT).IgG-positive samples were tested for IgG avidity.RESULTS The WNV-RNA detection rates were significantly higher in the urine(54.5%)/serum(46.4%)than in CSF(32.2%).According to the sampling time,the WNV-RNA detection rates in urine collected within 7 days/8-14/≥15 days were 29.4/66.6/62.5%(P=0.042).However,these differences were not observed in the CSF.The median RT-PCR cycle threshold values were significantly lower in urine(32.5,IQR=28-34)than in CSF(34.5,IQR=33-36).The frequency of positive WNV IgM and IgG significantly differed according to the sampling time in serum but not in CSF.Positive IgM/IgG antibodies were detected in 84.3/9.3%of serum samples collected within 7 days,100/71.1%of samples collected 8-14,and 100%samples collected after≥15 days.Recent WNV infection was confirmed by low/borderline avidity index(AI)in 13.6%of asymptomatic individuals.A correlation between ELISA and AI was strong negative for IgM and strong positive for IgG.No significant correlation between ELISA IgG and VNT was found.CONCLUSION The frequency of WNV RNA and antibody detection depends on the sampling time and type of clinical samples.IgG avidity could differentiate recent WNV infections from long-persisting IgM antibodies.

Epidemiology of hepatitis E in South-East Europe in the "One Health" concept

The significance of hepatitis E virus(HEV)as an important public health problem is rising.Until a decade ago,cases of HEV infection in Eur-ope were mainly confined to returning travelers,but nowadays,hepatitis E represents an emerging zoonotic infection in many European countries.The aim of this manuscript is to perform a systematic review of the published literature on hepatitis E distribution in humans,animals and environmental samples("One Health"concept)in the South-Eastern European countries.Comparison of the available data showed that the anti-HEV seroprevalence in the South-Eastern Europe varies greatly,depending on the population studied,geographical area and methods used.The IgG seroprevalence rates in different population groups were found to be 1.1%-24.5%in Croatia,up to 20.9%in Bulgaria,5.9-%17.1%in Romania,15%in Serbia,up to 9.7%in Greece and 2%-9.7%in Albania.Among possible risk factors,older age was the most significant predictor for HEV seropositivity in most studies.Higher seroprevalence rates were found in animals.HEV IgG antibodies in domestic pigs were detected in 20%-54.5%,29.2%-50%,38.94%-50%and 31.1%-91.7%in Serbia,Bulgaria,Romania and Croatia,respectively.In wild boars seroprevalence rates were up to 10.3%,30.3%and 31.1%in Romania,Slovenia and Croatia,respectively.A high HEV RNA prevalence in wild boars in some countries(Croatia and Romania)indicated that wild boars may have a key role in the HEV epidemiology.There are very few data on HEV prevalence in environmental samples.HEV RNA was detected in 3.3%and 16.7%surface waters in Slovenia and Serbia,respectively.There is no evidence of HEV RNA in sewage systems in this region.The available data on genetic characterization show that human,animal and environmental HEV strains mainly belong to the genotype 3.

Epidemiology of hepatitis C in Croatia in the European context

We analyzed prevalence, risk factors and hepatitis C virus(HCV) genotype distribution in different population groups in Croatia in the context of HCV epidemiology in Europe, with the aim to gather all existing information on HCV infection in Croatia which will be used to advise upon preventive measures. It is estimated that 35000-45000 of the Croatian population is chronically infected with HCV. Like in other European countries, there have been changes in the HCV epidemiology in Croatia over the past few decades. In some risk groups(polytransfused and hemodialysis patients), a significant decrease in the HCV prevalence was observed after the introduction of routine HCV screening of blood/blood products in 1992. Injecting drug users(IDUs) still represent a group with the highest risk for HCV infection with prevalence ranging from 29% to 65%. Compared to the prevalence in theCroatian general population(0.9%), higher prevalence rates were found in prison populations(8.3%-44%), human immunodeficiency virus-infected patients(15%), persons with high-risk sexual behavior(4.6%) and alcohol abusers(2.4%). Low/very low prevalence was reported in children and adolescents(0.3%) as well as in blood donors(0%-0.009%). In addition, distribution of HCV genotypes has changed due to different routes of transmission. In the general population, genotypes 1 and 3 are most widely distributed(60.4%-79.8% and 12.9%-47.9%, respectively). The similar genotype distribution is found in groups with high-risk sexual behavior. Genotype 3 is predominant in Croatian IDUs(60.5%-83.9%) while in the prison population genotypes 3 and 1 are equally distributed(52.4% and 47.6%). Data on HCV prevalence and risk factors for transmission are useful for implementation of preventive measures and HCV screening.

Emerging and neglected zoonoses in transplant population

Zoonoses represent a problem of rising importance in the transplant population.A close relationship and changes between human,animal and environmental health(“One Health”concept)significantly influence the transmission and distribution of zoonotic diseases.The aim of this manuscript is to perform a narrative review of the published literature on emerging and neglected zoonoses in the transplant population.Many reports on donor-derived or naturally acquired(re-)emerging arboviral infections such as dengue,chikungunya,West Nile,tick-borne encephalitis and Zika virus infection have demonstrated atypical or more complicated clinical course in immunocompromised hosts.Hepatitis E virus has emerged as a serious problem after solid organ transplantation(SOT),leading to diverse extrahepatic manifestations and chronic hepatitis with unfavorable outcomes.Some neglected pathogens such as lymphocytic choriomeningitis virus can cause severe infection with multi-organ failure and high mortality.In addition,ehrlichiosis may be more severe with higher casefatality rates in SOT recipients.Some unusual or severe presentations of borreliosis,anaplasmosis and rickettsioses were also reported among transplant patients.Moreover,toxoplasmosis as infectious complication is a well-recognized zoonosis in this population.Although rabies transmission through SOT transplantation has rarely been reported,it has become a notable problem in some countries.Since the spreading trends of zoonoses are likely to continue,the awareness,recognition and treatment of zoonotic infections among transplant professionals should be imperative.

Insights into hepatitis E virus epidemiology in Croatia

BACKGROUND Hepatitis E virus(HEV)is an emerging virus of global health concern.The seroprevalence rates differ greatly according to geographic region and population group.AIM To analyze the seroprevalence of HEV in exposed(animal-related professions)and nonexposed populations,as well as solid organ and hematopoietic stem cell transplant patients.METHODS Forestry workers(n=93),hunters(n=74),and veterinarians(n=151)represented the exposed population.The general population(n=126)and pregnant women(n=118)constituted the control group.Transplant patients included liver transplant recipients(LTRs)(n=83),kidney transplant recipients(KTRs)(n=43),and hematopoietic stem cell transplant recipients(HSCRs)(n=39).HEV immunoglobulin G antibodies were detected using the enzyme-linked immunosorbent assay and confirmed by the immunoblot test.RESULTS The HEV seroprevalence significantly differed between groups:Veterinarians 15.2%,hunters 14.9%,forestry workers 6.5%,general population 7.1%,and pregnant women 1.7%.In transplant patients,the seropositivity was highest in LTRs(19.3%),while in KTRs and HSCRs,the seroprevalence was similar to the general population(6.9%and 5.1%,respectively).A significant increase in seropositivity with age was observed from 2.9%in individuals less than 30 years to 23.5%in those older than 60 years.Sociodemographic characteristics(sex,educational level,area of residence,and number of household members),eating habits(game meat,offal,and pork products consumption),and environmental and housing conditions(drinking water supply,type of water drainage/sewer,waste disposal,domestic animals)were not associated with HEV seropositivity.However,individuals who reported a pet ownership were more often seropositive compared to those who did not have pet animals(12.5%vs 7.0%).CONCLUSION The results of this study showed that individuals in professional contact with animals and LTRs are at higher risk for HEV infection.In addition,age is a significant risk factor for HEV seropositivity.

Cauda equina arachnoiditis–a rare manifestation of West Nile virus neuroinvasive disease:A case report

BACKGROUND Data regarding the neuroradiology features of the West Nile virus neuroinvasive disease(WNV NID)is rather scarce.To contribute to the knowledge of the WNV NID,we present a patient with a combination of encephalitis and acute flaccid paresis,with cauda equina arachnoiditis as the main magnetic resonance(MR)finding.CASE SUMMARY A 72-year-old female patient was admitted due to fever,headache and gait instability.During the first several days she developed somnolence,aphasia,urinary incontinence,constipation,and asymmetric lower extremities weakness.Cerebrospinal fluid analysis indicated encephalitis.Native brain computed tomography and MR were unremarkable,while spinal MR demonstrated cauda equina enhancement without cord lesions.Virology testing revealed WNV IgM and IgG antibodies in serum and cerebrospinal fluid,which confirmed acute WNV NID.The treatment was supportive.After two months only a slight improvement was noticed but cognitive impairment,loss of sphincter control and asymmetric inferior extremities weakness remained.The patient died after a month on chronic rehabilitation.CONCLUSION Cauda equina arachnoiditis is a rare,but possible neuroradiological feature in acute flaccid paresis form of WNV NID.

Hepatitis E virus in professionally exposed: A reason for concern?

The zoonotic risk of hepatitis E virus(HEV)is well established.The HEV seroprevalence rates vary according to geographical region,assays used,and study cohorts.HEV infection is still underdiagnosed,implying the need to evaluate the disease's burden in the general population and specific risk groups,such as professionally exposed.Close contact with various animal reservoirs such as pigs,rabbits,sheep,dogs,wild boars,and deer has been associated with higher anti-HEV seroprevalence as a part of occupational exposure.While exact transmission routes remain to be determined,some general preventive measures such as proper hand hygiene,the usage of personal protective equipment,and the thermal processing of food before consumption should be followed.A“One-Health”multisectoral approach should be implemented to achieve optimal health and well-being outcomes,recognizing the interconnections between humans,animals,plants,and their shared environment,in which a vaccine against the zoonotic genotypes 3 and 4 and swine vaccination should be considered as a possible public health measure.This opinion review comprehensively addresses the HEV burden of professional exposure for butchers,slaughterhouse workers,veterinarians,farmers,hunters,and forestry workers delineates the current limits of protective work measures,and tackles future directions.

Comparison of indirect immunofluorescence and western blot method in the diagnosis of hantavirus infections

BACKGROUND Serologic cross-reactivity between hantaviruses often complicates the interpretation of the results.AIM To analyze the diagnostic value of indirect immunofluorescence assay(IFA)and western blot(WB)in the diagnosis of hantavirus infections.METHODS One hundred eighty-eight serum samples from Puumala(PUUV)and Dobrava(DOBV)orthohantavirus infected patients were analyzed.Serology was performed using commercial tests(Euroimmun,Lübeck,Germany).RESULTS Using IFA,49.5%of acute-phase samples showed a monotypic response to PUUV,while 50.5% cross-reacted with other hantaviruses.The overall cross-reactivity was higher for immunoglobulin G(IgG)(50.0%)than for immunoglobulin M(IgM)(25.5%).PUUV IgM/IgG antibodies showed low/moderate reactivity with orthohantaviruses Hantaan(12.3%/31.5%),Seoul(7.5%/17.8%),DOBV(5.4%/28.1%),and Saaremaa(4.8%/15.7%).Both DOBV IgM and IgG antibodies were broadly reactive with Hantaan(76.2%/95.2%),Saaremaa(80.9%/83.3%),and Seoul(78.6%/85.7%)and moderate with PUUV(28.5%/38.1%).Using a WB,serotyping was successful in most cross-reactive samples(89.5%).CONCLUSION The presented results indicate that WB is more specific than IFA in the diagnosis of hantavirus infections,confirming serotype in most IFA cross-reactive samples.