Virology Section Research Articles

Development of learning objectives to support undergraduate virology curriculum guidelines.

It has become increasingly important for microbiology educators to help students learn critical concepts of the discipline. This is particularly true in virology, where current challenges include increasing rates of vaccine hesitancy, misinformation about the COVID-19 pandemic, and controversy surrounding research on pathogens with pandemic potential. Having students learn virology can attract more people to the field and increase the number of people who can engage in meaningful discourse about issues relating to the discipline. However, the limited number of virologists who teach undergraduates, combined with the fact that many institutions lack stand-alone virology courses, results in virology often being taught as a limited number of lectures within an undergraduate microbiology course (if it is covered at all), which may or may not be taught by an individual trained as a virologist. To provide a framework to teach virology to undergraduate students, a team of virology educators, with support from the American Society for Virology (ASV), developed curriculum guidelines for use in a stand-alone undergraduate virology course or a virology section within another course (D. B. Kushner et al., J Virol 96:e01305-22, 2022, https://doi.org/10.1128/jvi.01305-22). These guidelines are available at the ASV website (https://asv.org/curriculum-guidelines/). To assist educators in implementing these guidelines, we created examples of measurable learning objectives. This perspective provides details about the virology curriculum guidelines and learning objectives and accompanies the perspective by Boury et al. in this issue of the Journal of Microbiology & Biology Education (25:e00126-24, 2024, https://doi.org/10.1128/jmbe.00126-24) about the recent revision of the microbiology curriculum guidelines overseen by the American Society for Microbiology.

Viral Load of HBV and HCV Correlation to Torque Teno Virus (TTV) Co-Infection in Iraqi Patients

Abstract Background: While hepatitis viruses A–E are established, emerging evidence points to additional, novel viral hepatitis agents. The torqueteno virus (TTV) has garnered interest due to its prevalence among patients with hepatitis, suggesting potential hepatotropism. Aim: This study was conducted to detect TTV antigens in individuals infected with chronic hepatitis B (HBV) and/or C (HCV) using molecular diagnostics and to explore any associations between TTV presence and demographic characteristics of the cohort. Materials and Methods: The current study was conducted from the period of September 2022 to April 2023, the investigation involved Iraqi patients aged between 32 and 83 years and diagnosed with HBV and HCV in National Iraqi Central Laboratories, Virology Section. We employed real-time PCR to quantify HBV and HCV viral loads and conventional PCR for TTV DNA detection. Results: TTV DNA was detected in 17 of the 60 patients (28.3%) with chronic HBV and HCV infections. Viral load distribution was found to be similar for both HBV and HCV. An age-related increase in viral load was noted, suggesting a trend where older individuals exhibited higher concentrations. However, no significant variation was observed that could link alterations in HBV and HCV viral loads to TTV status directly. Statistical analysis indicated a positive correlation between age and the likelihood of presenting with the virus, aligning with observed trends in other age-associated chronic conditions, such as Type 2 diabetes mellitus and chronic kidney disease. Conclusion: The presence of TTV in patients with enduring HBV or HCV infection could implicate the virus as a contributing factor to hepatitis pathology. Studies such as this are pivotal for elucidating the age-associated risk profiles for various pathologies and shaping corresponding public health policies and preventative approaches.

Effects of meteorological variables on potato leaf roll virus and potato virus y infections on different potato varieties under natural and mulched conditions

After rice and wheat, potatoes are the third most important staple crop in Pakistan, but due to various virus diseases attacks, yield remains very low. Among viral pathogens, potato leaf roll virus (PLRV) and potato virus Y (PVY) are the most destructive viruses present in all potato-growing areas. A field experiment was conducted at the Research Farm of Plant Virology Section, Ayub Agricultural Research Institute, Faisalabad, to evaluate the effects of meteorological variables on the development of virus infections (PLRV and PVY) on different potato varieties under natural and mulched conditions. Results indicated that the development of infections of PVY and PLRV was delayed in different potato varieties under mulched conditions. The potato variety Simply Red had the highest PLRV and PVY disease incidences under unmulched and mulched circumstances, while Sahiwal Red and Ruby had the lowest infection rates. The least PVY disease incidence was noted under mulched conditions on FD-81-1. Mulched conditions were better in the reduction of diseases than unmulched conditions. The average high temperature (HT) ranged from 21.9 ◦C to 27 ◦C was most favorable for the development of PLRV and PVY on all six tested potato varieties in both conditions. The average low temperature (LT) ranged from 8 ◦C to 15 ◦C was favorable for the progression of PLRV and PVY diseases in both conditions. The relative humidity (RH) range of 50-60% was conducive for the development of PLRV and PVY diseases. It is concluded that mulching application is an essential tool to enhance the yield of potato crops by reducing their specific diseases.

Burden of Rotavirus Diarrhoea in Children in Abuja

Background: Diarrhoea is the second leading cause of death in children. Nigeria has the continent’s highest mortality due to diarrhoeal diseases with little information on specific causes and the proportion affected by rotavirus infection. The main objectives of this study were to describe the features of young children with diarrhoea, with and without rotavirus, in Abuja the Federal Capital Territory. Materials and Methods: Retrospective review of local hospital activity data related to diarrhoea was retrieved from General Hospitals in Abuja. Then a one-year prospective descriptive study of children under 5 years of age with acute diarrhoea was conducted from September 2012 to August 2013. Children with acute diarrhoea attending three government hospitals and one private hospital were recruited. Children without diarrhoea were recruited as the control group. Faecal specimens were transported in cold chain boxes from Nigeria and stored at -80 °C at the Institute of Global Health, virology section of the University of Liverpool, where all laboratory work was performed. Results: Hospital records were poorly preserved and did not provide meaningful data for trend analyses or disease surveillance. 1331 participants were enrolled in this prospective study. Stool samples were collected from 1242 (93.3%) participants, of whom 957 (77.0%) were ambulatory, 123 (9.9%) hospitalised and 160 (12.8%) controls without diarrhoea. 881 and 450 children with diarrhoea were recruited from government and the private hospitals, respectively. The median age of the children was 8 months in the ambulatory and 9.5 months in the hospitalized group (p<0.05). A total of 209 (16.8%) children were vaccinated, 858 (69.1%) were unvaccinated, and 174 (14.0%) had an unclear vaccination status. Rotavirus ELISA was positive in 123 (11.4%) children with diarrhoea and 2 (1.2%) controls. Among children with diarrhoea, 92 (10.4%) of 881 children attending government hospitals had rotavirus, compared to 33 (7.3%) of 450 children attending a private hospital (p<0.001) where a vaccination program had been in place. The peak months for rotavirus infection were November and February. The efficacy of Rotarix® RV1 vaccine in preventing rotavirus diarrhoea was indirectly assessed to be 64.5%. Conclusion: Rotavirus is an important pathogen in children, especially in unvaccinated children in Abuja. The introduction of a rotavirus vaccine is highly desirable in Nigeria, but this is still awaited. Local and national infrastructure are inadequate for basic surveillance of diarrhoeal disease, and this will have to be improved, together with access to virological stool testing, to monitor the planned vaccine program. The retrospective studies reported here provide indirect evidence of vaccine efficacy in Abuja but need prospective confirmation.

Regression Modeling Strategies to Predict and Manage Potato Leaf Roll Virus Disease Incidence and Its Vector

The potato leaf roll virus (PLRV) disease is a serious threat to successful potato production and is mainly controlled by integrated disease management; however, the use of chemicals is excessive and non-judicious, and it could be rationalized using a predictive model based on meteorological variables. The goal of the present investigation was to develop a disease predictive model based on environmental responses viz. minimum and maximum temperature, rainfall and relative humidity. The relationship between epidemiological variables and PLRV disease incidence was determined by correlation analysis, and a stepwise multiple regression was used to develop a model. For this purpose, five years (2010–2015) of data regarding disease incidence and epidemiological variables collected from the Plant Virology Section Ayub Agriculture Research Institute (AARI) Faisalabad were used. The model exhibited 94% variability in disease development. The predictions of the model were evaluated based on two statistical indices, residual (%) and root mean square error (RMSE), which were ≤±20, indicating that the model was able to predict disease development. The model was validated by a two-year (2015–2017) data set of epidemiological variables and disease incidence collected in Faisalabad, Pakistan. The homogeneity of the regression equations of the two models, five years (Y = −47.61 − 0.572x1 + 0.218x2 + 3.78x3 + 1.073x4) and two years (Y = −28.93 − 0.148x1 + 0.510x2 + 0.83x3 + 0.569x4), demonstrated that they validated each other. Scatter plots indicated that minimum temperature (5–18.5 °C), maximum temperature (19.1–34.4 °C), rainfall (3–5 mm) and relative humidity (35–85%) contributed significantly to disease development. The foliar application of salicylic acid alone and in combination with other treatments significantly reduced the PLRV disease incidence and its vector population over control. The salicylic acid together with acetamiprid proved the most effective treatment against PLRV disease incidence and its vector M. persicae.

Comparative Evaluation of Three Diagnostic Tools for the Detection of Hepatitis C Virus among High-risk Individuals in a Tertiary Care Centre of Northeast India

Introduction: Hepatitis C virus (HCV) has posed a major public health problem globally. Since majority of HCV infected patients are asymptomatic, diagnosis of HCV infection is mainly based on the detection of anti-HCV antibodies by the Enzyme Linked Immunosorbent Assay (ELISA) or Rapid Diagnostic Tests (RDTs) and HCV Ribonucleic Acid (RNA) by real time Polymerase Chain Reaction (PCR) of serum or plasma samples. Aim: To assess the performance of RDT and 4th generation ELISA against real time reverse transcriptase PCR for the detection of HCV. Materials and Methods: A hospital-based cross-sectional study was carried out in the Virology Section, Department of Microbiology, Jawaharlal Nehru Institute of Medical Sciences (JNIMS), Imphal, Manipur, India, for a period of two years from June 2019 to May 2021. The study included 3,254 plasma samples from suspected cases of HCV monoinfection, and HCV/HIV co-infection. The plasma samples were subjected to anti-HCV antibodies by RDT (SD BIOLINE, South Korea) and 4th generation ELISA (Monolisa™ HCV Ag-Ab ULTRA, BioRad, France), and HCV RNA by real time PCR. Data analysis was done using descriptive statistics, and performance of the assays was evaluated by using Cohen kappa test (κ) and Receiver Operating Characteristic (ROC) curve. Results: PCR is considered as the gold standard test. HCV was detected by RDT in 453 (13.92%), ELISA in 413 (12.69%) and RT-PCR in 367 (11.28%) samples. The present study demonstrated sensitivity of 97.55% and specificity of 96.71% with Positive Predictive Value (PPV) of 79.03% by HCV-RDT. The 4th generation ELISA showed high sensitivity of 99.46% and specificity of 98.34%. Using ROC curve, the area under the curve was 81% for ELISA with diagnostic accuracy of 98.46%. Conclusion: 4th generation ELISA is more sensitive and specific than RDT for the detection of HCV infection. Confirmatory HCV-RNA assay could be performed to clear doubts related to false-positive and false-negative findings of the primary screening assays.

Whole-genome analysis to describe a human adenovirus D8 conjunctivitis outbreak in a tertiary hospital.

Conjunctivitis is a frequent ocular disorder caused by human adenoviruses (HAdVs). Only a few of the 45 HAdV-D species are associated with epidemic keratoconjunctivitis, including HAdV-D8. Nosocomial outbreaks due to HAdV-D8 have been rarely described, because keratoconjunctivitis cases are clinically diagnosed and treated without having to characterize the causative agent. Moreover, molecular typing is tedious when using classical techniques.In this study, a hospital outbreak of conjunctivitis caused by HAdV-D8 was characterized using the recently developed whole-genome sequencing (WGS) method. Of the 363 patients attending the Ophthalmology Department between July 13 and August 13, 2018, 36 may have acquired intrahospital conjunctivitis. Also, 11 of 22 samples sent to the Virology section were selected for WGS analysis.The WGS results revealed that 10 out of 11 HAdV-D8 strains were closely related. The remaining strain (Case 28) was more similar to a strain from an outbreak in Germany obtained from a public sequence database. WGS results showed that outbreak HAdV-D8 strains had a minimum percentage of identity of 94.3%.WGS is useful in a clinical setting, because it avoids carrying out viral culture or specific polymerase chain reactionsequencing. The public availability of sequence reads makes it easier to compare clusters in circulation. In conclusion, WGS can play an important role in standard routines to describe viral outbreaks.

Subunit Vaccines Against Emerging Pathogenic Human Coronaviruses.

Seven coronaviruses (CoVs) have been isolated from humans so far. Among them, three emerging pathogenic CoVs, including severe acute respiratory syndrome coronavirus (SARS-CoV), Middle East respiratory syndrome coronavirus (MERS-CoV), and a newly identified CoV (2019-nCoV), once caused or continue to cause severe infections in humans, posing significant threats to global public health. SARS-CoV infection in humans (with about 10% case fatality rate) was first reported from China in 2002, while MERS-CoV infection in humans (with about 34.4% case fatality rate) was first reported from Saudi Arabia in June 2012. 2019-nCoV was first reported from China in December 2019, and is currently infecting more than 70000 people (with about 2.7% case fatality rate). Both SARS-CoV and MERS-CoV are zoonotic viruses, using bats as their natural reservoirs, and then transmitting through intermediate hosts, leading to human infections. Nevertheless, the intermediate host for 2019-nCoV is still under investigation and the vaccines against this new CoV have not been available. Although a variety of vaccines have been developed against infections of SARS-CoV and MERS-CoV, none of them has been approved for use in humans. In this review, we have described the structure and function of key proteins of emerging human CoVs, overviewed the current vaccine types to be developed against SARS-CoV and MERS-CoV, and summarized recent advances in subunit vaccines against these two pathogenic human CoVs. These subunit vaccines are introduced on the basis of full-length spike (S) protein, receptor-binding domain (RBD), non-RBD S protein fragments, and non-S structural proteins, and the potential factors affecting these subunit vaccines are also illustrated. Overall, this review will be helpful for rapid design and development of vaccines against the new 2019-nCoV and any future CoVs with pandemic potential. This review was written for the topic of Antivirals for Emerging Viruses: Vaccines and Therapeutics in the Virology section of Frontiers in Microbiology.

Bacteria and Viral Profile of Severe Acute Respiratory Infections of Children Attending Yangon Children’s Hospital and Yankin Children’s Hospital

Objectives of study are (1) to reinforce the national capacity for diagnosis and antibiogram of some infectious diseases causing severe acute respiratory infection (SARI) and (2) to build a network between hospital and laboratory for the diagnosis and surveillance of SARI in Yangon. This study is a crosssectional hospital- and laboratory-based descriptive study. A total of 825 samples including respiratory samples and blood samples from 511 children attending Yangon Children’s Hospital and Yankin Children’s Hospital from December 2014 to April 2016 for treatment of SARI were included. Identification and antibiotic sensitivity testing were done using Vitek 2. Out of 129 gram-negative bacilli (GNB), K. pneumoniae 32%, P. aeruginosa 18%, A. baumannii 13%, E. coli 9% were mostly isolated. Among 35 gram-positive cocci (GPC), S. aureus 42% and S. pneumoniae 6% were mostly isolated. Multidrug resistance rates were E. coli 100%, K. pneumoniae 95%, A. baumanii 82% and P. aeruginosa 17%. Extended-spectrum beta-latamase (ESBL)-producing K. pneumoniae and E. coli was 6 out of 10 tested organisms. Carbarpenemase-producing GNB and methicillin-resistant Staphylococcus aureus (MRSA) were 21% and 33%, respectively. Virology section tested 529 samples of 490 patients using the FTD33 Multiplex PCR method which can detect 33 pathogens including 20 viruses, 12 bacteria and 1 fungus. Out of 490 patients, 374 were PCR positive. Different types of samples including nasopharyngeal, throat, endotracheal and laryngeal swab, tracheal secretion and bronchoalveolar lavage, were tested. Out of 566 viruses, respiratory syncytial virus (RSV) (19.3%), rhinovirus (17.0%), parechovirus (14.3%), bocavirus (11.1%), adenovirus (10.2%), metapneumo-virus A and B (10.2%), parainfluenza virus (5.7%), enterovirus (3.0%), influenza A virus (2.8%), coronavirus (4%), parainfluenza virus (0.9%) and influenza C virus (0.4%) were detected. This study highlighted the etiological agents of bacteria, viruses and drug-resistant bacterial pathogens in SARI.

Evidence of B-cell dysregulation in severe CNS inflammation after alemtuzumab therapy.

Cases of severely exacerbated CNS inflammation have been described in patients with MS under treatment with alemtuzumab, a pan-lymphocyte–depleting anti-CD52 monoclonal antibody.1,2 On the basis of the peripheral lymphocyte subset network (higher B-cell and suppressed T-cell counts)2 and marked clinical improvement following plasmapheresis and rituximab treatment (anti-CD20 antibody),1 a B-cell–driven intrathecal autoimmune reaction was hypothesized. Acknowledgment: The authors thank Dr. Lucia Rossi, of the Virology Section of the Department of Molecular Medicine, University of Padua, for EBV DNA testing in blood and CSF.

TORCH Screening Test in Pregnant Women of Kirkuk City

In the course of pregnancy, the developing fetus might have some infections that can be transmit to him transplacentally from his mother. Early identification and treatment of these infections in a neonates is essential. Prenatal caution comprehends a range of tests, involving a TORCH screen test.From the beginning of July till the end of December 2014. 500 blood samples were collected for TORCH screening from pregnant women whom attended virology section in Azadi Teaching Hospital. The TORCH screening was performed using ELISA technique.The result of TORCH screening tests was not differed significantly between year 2013 and 2014, but there was significant differences between the frequency of the microorganisms included in TORCH screening, the highest was for Cytomegalovirus and Rubella with rates of 29.2, 39.1 % and 30.3, 41.8 % for each of the two viruses respectively. Lower frequency was observed for Toxoplasma with rate of 9.5, 8.9 % followed by Herpes simplex virus with a rate of only 1.1, 2.6 %. High rate of mixed infection were between Cytomegalovirus and Rubella. The frequency of chronic infections were significantly higher comparing with acute and subacute cases. The rate of infections was not effected by patients age.Cytomegalovirus, Rubella and Toxoplasma are prevalent among pregnant women in Kirkuk city and probably they are the causative agents of abortion and infertility found among them, therefore it's better for pregnant woman or those planning to become pregnant to be tested for TORCH infections, and vaccinated against Rubella, Cytomegalovirus, Herpes simplex virus and Toxoplasma to grantee her health as well as her baby.

Sequence analysis and evaluation of the NS3/A gene region of bluetongue virus isolates from South Africa.

Phylogenetic networks and sequence analysis allow a more accurate understanding of the serotypes, genetic relationships and epidemiology of viruses. Based on gene sequences of the conserved segment 10 (NS3), bluetongue virus (BTV) can be divided into five topotypes. In this molecular epidemiology study, segment 10 sequence data of 11 isolates obtained from the Virology Section of the Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Onderstepoort, were analyzed and compared to sequence data of worldwide BTV strains available in the GenBank database. The consensus nucleotide sequences of NS3/A showed intermediate levels of variation, with the nucleotide sequence identity ranging from 79.72 % to 100 %. All 11 strains demonstrated conserved amino acid characteristics. Phylogenetic networks were used to identify BTV topotypes. The phylogeny obtained from the nucleotide sequence data of the NS3/A-encoding gene presented three major and two minor topotypes. The clustering of strains from different geographical areas into the same group indicated spatial spread of the segment 10 genes, either through gene reassortment or through the introduction of new strains from other geographical areas via trade. The effect of reassortment and genetic drift on BTV and the importance of correct serotyping to identify viral strains are highlighted.

Kuan-Teh Jeang

Kuan-Teh Jeang

In memoriam: Kuan-Teh Jeang, MD PhD (1958–2013)

In memoriam: Kuan-Teh Jeang, MD PhD (1958–2013)

PREVALENCIA DA RAIVA EM BOVINOS, OVINOS E CAPRINOS NO ANO DE 2007 NO ESTADO DO PARANÁ

PREVALENCE OF RABIES IN CATTLE, SHEEP AND GOATS IN PARANA IN 2007 Rabies is an infectious disease caused by RNA viruses in the family Rhabdoviridae, genus Lyssavirus. The infection is invariably fatal and mainly affects the central nervous system. In 2007, a total of 446 cattle, 13 sheep, and 7 goats were attended to at the Virology section of Centro de Diagnosticos Marcos Enrietti, Parana. Blood samples were tested by direct immunofluorescence and biological tests for detection of rabies. Sera analysis revealed that 191 (42,8%) cows and 13 (23%) sheep were positive, and all samples from goats were negative. Results indicate the need to develop control measures against the occurrence of rabies in ruminants, especially cattle. Furthermore, other nervous system diseases should be researched in order to clarify rabies diagnosis.

Cytomegalovirus in the intensive care unit: Pathogen or passenger?*

Medical Virology Section; Laboratory of Clinical Infectious Diseases; National Institutes of Health; Bethesda, MD The author has not disclosed any potential conflicts of interest.

6Th Australasian Viral Hepatitis Conference

The Australasian Viral Hepatitis conference is a bi-annual meeting that brings together researchers from a diverse range of fields including clinical medicine, epidemiology, social research and basic virology research. The 6th Viral Hepatitis meeting was held in Brisbane, Australia in October 2008, and had keynote speakers including Brian Edlin from New York, speaking on HCV, Stephen Locarnini from VIDRL in Melbourne on HBV and Ching-Lung Lai from Hong Kong on hepatocellular carcinoma. The virology section included symposia on hepatitis B and model systems, and hepatitis C pathogenesis, treatment and immunity.

How the Complete Sequencing of the Domestic Cat Genome can Benefit Basic AIDS Research

Mauro Pistello† & Mauro Bendinelli †Author for correspondence Retrovirus Center & Virology Section, Department of Experimental Pathology, University of Pisa Via San Zeno, 35 Pisa, I-56127, Italy Tel.: +39 050 221 3781; Fax: +39 050 221 3524; pistello@biomed.unipi.it ‘...detailed knowledge of the domestic cat genome will likely help to address many of the considerable challenges in AIDS research...’

Report of the 13th European Association for Potato Research Virology Section Meeting 17–22 June 2007, Coylumbridge (Aviemore), Scotland, United Kingdom

The 13th triennial meeting of the Virology Section of the European Association for Potato Research (EAPR), hosted by the Scottish Agricultural Science Agency (SASA) and the Scottish Crop Research Institute (SCRI) was held at the Hilton Hotel, Coylumbridge, Aviemore, set in a woodland estate in the centre of the Cairngorm National Park, the largest national park in the UK. It was the first time that the meeting had been held in Scotland and it was used to celebrate the EAPR’s 50th anniversary. Over 70 delegates from all continents attended. Generous sponsorship received from a range of UK and overseas companies/organizations enabled financial assistance to be provided to keynote speakers, and travel grants to delegates from Argentina, Australia, Brazil, Pakistan, Poland and Turkey. The meeting was opened by Colin Jeffries, who provided a potted history of the EAPR and the Virology Section. Continuing the historical theme, Bryan Harrison gave his keynote lecture to celebrate 50 years of the EAPR, “Fifty years of potato virus research: achievements and changing concerns”. There then followed scientific sessions that dealt with: resistance; plant–virus interactions; epidemiology and control of virus-vector insects; impact of climate change on virus incidence and spread; non-European/global virus issues; soil-borne viruses; certification/quarantine; and diagnostic testing. Keynote papers were given by Gad Loebenstein (“Understanding natural resistance mechanisms—will it lead to obtaining resistant cultivars?”), Lesley Torrance (“Soil-borne virus diseases of potato with particular reference to Potato mop-top virus”), Richard Harrington (“Vectors and viruses in a warmer world”), Luis Salazar (“Global potato virus issues”) and Rick Mumford (“Making diagnostics work: getting it right, every time for the right price”). In all, some 38 oral papers and 23 posters were presented. The social events included a welcome reception hosted by the Highland Council; dinner at The Ptarmigan, the UK's highest restaurant, at 1,100 m, just under the summit of Cairn Gorm, reached by funicular railway; a visit to a whisky distillery Potato Research (2008) 51:175–208 DOI 10.1007/s11540-008-9098-x

Impacto económico del dengue y del dengue hemorrágico en el Estado de Zulia, Venezuela, 1997-2003

To determine the direct and indirect costs of medical care provided to cases of dengue and dengue hemorrhagic fever/dengue shock syndrome (DHF/DSS) between 1997 and 2003 in Zulia State, Venezuela. The total number of patients with dengue and DHF/DSS was obtained from records belonging to the Regional Epidemiology Office of the state of Zulia and from reports of cases that were confirmed in the Virology Section of Dr. Americo Negrette's Clinical Research Institute, Zulia University, Maracaibo, Venezuela, between 1 January 1997 and 31 December 2003. Direct costs included the cost of emergency medical care for all cases and hospital costs for cases with DHF/DSS (cost per bed-day and laboratory expenses). The costs connected to absence from work among patients over 15 years of age and mothers who accompanied their children under 15 years of age comprised the indirect costs, which were adjusted for the proportion of men and women in the labor force. Calculations were based on the minimum yearly wage, and results were given in United States dollars, converted according to each year's average exchange rate. During the study period, 33,857 cases of dengue and DHF/DSS were seen. Of them, 30 251 (89.35%) were cases of dengue, and 3606 (10.65%) were cases of DHF/DSS. Six cases of DHF/DSS died (lethality rate: 0.2 per 100 cases of DHF/DSS). Direct costs were 474,251.70 US dollars; of these costs, 132,042.30 US dollars were spent on emergency medical care and 342,209.40 US dollars on the hospital costs of DHF/DSS cases. Indirect costs were 873,825.84 US dollars and comprised 64.8% of overall expenditures (1 ,48,077.54 US dollars) connected to this disease during the study years. This is the first study on the economic impact of dengue in the state of Zulia and in Venezuela. In spite of some limitations, results show that dengue is an important public health problem that causes great expense because of temporary absenteeism from work and that undermines regional and national economic development.