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MAJOR ARTICLE Randomized, Controlled Trial of Oral Ribavirin for Japanese Encephalitis in Children in Uttar Pradesh, India Rashmi Kumar,1 Piyush Tripathi,1 Madan Baranwal,1 Sudhakar Singh,1 Sanjeev Tripathi,1 and Gopa Banerjee2 Departments of 1Pediatrics and 2Microbiology, Chhatrapati Shahuji Maharaj Medical University, Lucknow, Uttar Pradesh, India (See the editorial commentary by Chapman on pages 407–9) Background. Japanese encephalitis is associated with high rates of mortality and disabling sequelae. To date, no specific antiviral has proven to be of benefit for this condition. We attempted to determine the efficacy of oral ribavirin treatment for reducing early mortality among children with Japanese encephalitis in Uttar Pradesh, India. Methods. Children (age, 6 months to 15 years) who had been hospitalized with acute febrile encephalopathy (a ⭐2-week history of fever plus altered sensorium) were tested for the presence of immunoglobulin M antibodies to Japanese encephalitis virus with commercial immunoglobulin M capture enzyme-linked immunosorbent assay. Children with positive results were randomized to receive either ribavirin (10 mg/kg per day in 4 divided doses for 7 days) or placebo syrup through nasogastric tube or by mouth. The primary outcome was early mortality; secondary outcome measures were early (at hospital discharge; normal or nearly normal, independent functioning, dependent, vegetative state, or death) outcome, time to resolution of fever, time to resumption of oral feeding, duration of hospitalization, and late outcome (⭓3 months after hospital discharge). The study was double-blind, and analysis was by intention to treat. Results. A total of 153 patients were enrolled during a 3-year period; 70 patients received ribavirin, and 83 received placebo. There was no statistically significant difference between the 2 groups in the early mortality rate: 19 (27.1%) of 70 ribavirin recipients and 21 (25.3%) of 83 placebo recipients died (odds ratio, 1.10; 95% confidence interval, 0.5–2.4). No statistically significant differences in secondary outcome measures were found. Conclusions. For the dosage schedule used in our study, oral ribavirin has no effect in reducing early mortality associated with Japanese encephalitis. Trial registration. ClinicalTrials.gov identifier: NCT00216268. Japanese encephalitis (JE) is, at present, the single most important cause of viral encephalitis in Asia [1]. In addition to causing acute illness with a high mortality rate, the disease may leave survivors with major mental and physical disabilities, placing an enormous load on the very families who are least equipped to bear the burden of a handicapped child [2]. As with other flaviviruses, there is no known specific antiviral therapy for the infection. A double-blind, placebo-controlled Received 3 June 2008; accepted 23 September 2008; electronically published 14 January 2009. Reprints or correspondence: Prof. Rashmi Kumar, Dept. of Pediatrics, Chhatrapati Shahuji Maharaj Medical University, Lucknow (UP), India 226003 (rashmik2005 @gmail.com). Clinical Infectious Diseases 2009; 48:400–6 2009 by the Infectious Diseases Society of America. All rights reserved. 1058-4838/2009/4804-0005$15.00 DOI: 10.1086/596309 400 • CID 2009:48 (15 February) • Kumar et al. trial of administration of IFN-a-2a to Vietnamese children indicated no benefit [3]. There is, therefore, an urgent need for antiviral drug trials involving this devastating disease [4]. The drug ribavirin (1-b-d-ribofuranosyl-1,2,4-triazole-3-carboxamide) is a broad-spectrum antiviral agent, a synthetic nucleoside compound with ribose and triazole moieties that bears striking structural similarity to guanosine and inosine [5]. Ribavirin likely has multiple mechanisms of action, but these have not been fully elucidated. It appears to interfere with RNA and DNA synthesis, inhibiting protein synthesis and viral replication [6]. The drug is being marketed for human consumption and is approved for use for acute bronchiolitis caused by respiratory syncytial virus and for chronic hepatitis C [7]. Several in vitro [8–11] and animal [12–14] studies have demonstrated that ribavirin has an effect on pathogenic flaviviruses, including JE virus and West Nile virus. Human studies of ribavirin have been conducted for Lassa fever [15], Argentinian hemorrhagic fever [16, 17], hemorrhagic fever with renal syndrome [18], hantavirus pulmonary syndrome [19–21], influenza [22], severe acute respiratory syndrome [23], subacute sclerosing panencephalitis [24], La Crosse encephalitis [25], West Nile encephalitis [26], and HIV/AIDS [27]. However, placebo-controlled trials examining the efficacy and safety of this agent are rare, and those that have demonstrated efficacy are even more so [15–18]. In certain South Asian countries, ribavirin is used empirically to treat JE [28, 29]. Here, we report the results of, to our knowledge, the first randomized, doubleblind, placebo-controlled trial of ribavirin for treatment of JE. METHODS Study site. The study was performed in the pediatric wards of Chhatrapati Shahuji Maharaj Medical University in Lucknow, the capital city of Uttar Pradesh—the “northern state,” India’s most populous state and also one of its poorest, with the lowest human development indices [30]. Chhatrapati Shahuji Maharaj Medical University is a teaching hospital that caters mostly to poor and severely ill persons from the city and surrounding districts, extending up to Nepal. Objective. We aimed to evaluate the benefit of the antiviral drug ribavirin on the outcome of JE. Prior approval was obtained from the Institutional Ethics Committee and Drug Controller General of India. Consent and adverse event forms were completed for each patient. Screening. During the period from July 2005 through November 2007, we actively tested children who had been hospitalized with acute febrile encephalopathy for JE during every monsoon or postmonsoon season (i.e., July through November). Inclusion criteria for testing were age of 16 months and the presence of acute febrile encephalopathy, which was defined as a ⭐2-week history of fever plus altered sensorium in a previously healthy child. Exclusion criteria for testing were as follows: (1) a firm diagnosis of bacterial or tuberculous meningitis based on examination of CSF specimens or imaging findings, or (2) frank hepatic encephalopathy with jaundice. Children who met the aforementioned criteria were considered to have acute encephalitis and underwent IgM ELISA testing of CSF specimens (if available) or blood specimens. Testing was performed the morning after hospital admission, and attempts were made to have the ELISA results within 24 h after hospital admission. Patients from the pediatric wards of Baba Raghav Das Medical College (Gorakhpur, India) in 2006 and Vivekanand Hospital (Lucknow) in 2007 were also screened using similar criteria. ELISAs. We tested for the presence of IgM against JE virus by IgM capture ELISA with use of the JE Chex kit (Excyton). The test results showed complete concordance with conventional ELISA results [31] and takes 3 h to perform. Only patients with an index value of ⭓100 were considered to have JE. On 3 occasions, kits marketed by Inbios USA and Panbio Australia were used instead. Drug and placebo. Ribavirin and placebo syrup were obtained from Lupin, the sole manufacturer of ribavirin in India, in identical 30-mL bottles. The placebo contained all of the ingredients of the ribavirin syrup except the active principle. Only a small code number on the bottles (10001 or 10002 for the first lot and 10003 or 10004 for the second lot) differentiated the drug and placebo bottles Randomization procedure. Generation of the allocation sequence was performed by a member of the study team who worked in the laboratory. Sequential numbers ending with the digits of either 1 or 2 were taken from a random number table. The numbers (1 or 2 ) were written in the same sequence on sheets of paper, which were folded and then placed in identical envelopes and sealed. The envelopes were numbered sequentially starting from 1. As soon as it was known that a patient had tested positive for JE virus, he or she was randomized to a study arm. The next envelope was opened by the project’s medical officer. If the envelope had a sheet bearing the number 1, a bottle coded 10001 was assigned to the patient; if the sheet bore the number 2, a bottle of syrup coded 10002 was assigned. In 2006, a second lot of bottles coded 10003 and 10004 was received, and sheets bearing numbers 3 and 4 were used in the same way. Blinding. The code provided by the company in a sealed envelope was kept locked and was revealed only at the end of the study, after analysis. The person who generated the sequence was not involved with clinical assessment for severity or outcome of illness. In November 2007, after data collection was complete, the codes were linked (i.e., the envelopes bearing information about the code were opened by a third person, who was not involved in the study, who told us which of the codes 10001 and 10002 were the same as codes 10003 and 10004). This allowed us to analyze the data. Enrollment, treatment, and diagnostic evaluation. After randomization, written consent was obtained from the patient’s guardian by the medical officer working in the project. A detailed history and the findings of physical and neurological examinations were recorded on predesigned data collection forms. Predetermined definitions for conditions such as acute febrile encephalopathy, acute encephalitis, and elevated intracranial tension were used. A standardized diagnostic evaluation for patients with suspected acute encephalitis was adopted. At hospital admission, we performed complete blood cell counts; examination of CSF specimens for cell count and determination Ribavirin for Japanese Encephalitis • CID 2009:48 (15 February) • 401 Figure 1. Flow chart of a study of patients with Japanese encephalitis (JE). BM, bacterial meningitis; LAMA, left hospital against medical advice; TBM, tuberculous meningitis. of sugar and protein levels; Gram stain and bacterial culture; smear and rapid tests for malaria; determination of the blood urea, serum electrolytes, and creatinine levels; and liver function tests. CT was performed whenever possible. Treatment of the patients was supportive and included use of antipyretics and anticonvulsants, nursing care, and administration of intravenous fluids and cerebral dehydrants, as needed. Intravenous ceftriaxone (100 mg/kg per day in 2 divided doses) was usually administered for a week. Ribavirin or placebo syrup was given through a nasogastric tube or orally once the child was conscious, at a dosage of 10 mg/kg per day in 4 divided doses for 7 days. Records of the codes on the ribavirin bottle were kept. In 2006, ventilators became available, and many children received mechanical ventilation support as the need arose. Follow-up and outcome. The patients were observed daily until they were discharged from the hospital. Intake of ribavirin (or placebo) syrup was checked daily. The primary outcome measured was mortality rate in the hospital. Note was also made 402 • CID 2009:48 (15 February) • Kumar et al. of time after commencement of treatment (in days) to resolution of fever and to resumption of oral feeding and total duration of hospitalization. In general, patients were discharged from the hospital once they could be fed by mouth and were afebrile. Hemoglobin and reticulocyte concentrations were again determined at hospital discharge or after 7–10 days if the child remained in the hospital, and any decreases in the hemoglobin concentration were noted. In many cases, the family of the patient preferred to take the child home once the outcome appeared to be hopeless. This was referred to as “leaving against medical advice.” In such cases, leaving against medical advice was equated with death in the hospital. In some cases, patients did not wait for discharge but just left the hospital without informing the hospital staff. Such patients were called “absconders.” If the patient was discharged from the hospital, the patient’s functional status at the time of discharge was recorded in terms of ability to comprehend speech, to feed, to speak, and to walk. After discharge from the hospital, the patients were given appointments for revisit every 3 months. If they did not attend the visit, a postal reminder was sent. In 2006 and 2007, the families of many patients possessed mobile phones, and a reminder could be made via telephone. At each visit, the functional status was assessed through a specially designed outcome questionnaire, a complete neurological examination was performed, and any other problems were noted. In some cases, outcome questionnaires were filled out via telephone interviews. From December 2007 through February 2008, 2 trained field workers actually visited the homes of patients and filled out the outcome questionnaires for survivors. Outcome was classified as normal or near normal, independent functioning, dependent, vegetative, or death, in accordance with the Glasgow Outcome Scale [32]. Sample size. The mortality rate for JE is ∼35% (it was 37% in a previous study [33] and was quoted to be 30% in a recent review [34]). To detect a decrease in the mortality rate of 20% with 95% confidence and 80% power, sample size per group totaled to 72 [35]. Data management and analysis. Baseline clinical features at hospital admission were compared between the ribavirin and placebo arms. The primary outcome factor (early mortality) was based on the sum of deaths in the hospital plus patients who left the hospital against medical advice in a poor general condition. Secondary outcome factors were time to resolution of fever, time until the patient could start feeding orally, duration of hospital stay, and early and late outcomes. Outcomes in the 2 groups were also dichotomized as “good” (i.e., normal, near normal, or independent functioning) or “bad” (death, leaving against medical advice in a poor general condition, lack of independent functioning, or vegetative state). These comparisons were made both at the time of hospital discharge (early Table 1. Clinical and laboratory features of ribavirin and placebo groups at hospital admission. Characteristic Demographic characteristic Age, mean months SD Male sex Mean weight-for-age percentage SD Clinical characteristic Ribavirin group (n p 70) Placebo group (n p 83) 90.5 32.9 59 (84.3) 92.2 33.6 62 (74.7) 74.0 12.39 74.4 12.13 Duration of illness, mean days SD 7.8 4.9 Mean GCS SD Convulsions Increased generalized muscle tone Focal deficit 7.1 70 35 25 Extrapyramidal signs Gastric bleeding Fundus blurring or papilledema, proportion of patients (%) S/o increased intracranial tensiona b Hyperventilation Decerebrate posturing Biological characteristic Hemoglobin concentration, mean g/dL SD Total leukocyte count, mean cells ⫻ 106/L SD 2.54 (100) (50.0) (35.7) 18 (25.7) 22 (31.4) 10/50 (20.0) 2.63 (98.8) (48.1) (43.4) 30 (36.1) 30 (36.1) 9/58 (15.5) 12 (17.1) 8 (9.6) 15 (21.4) 12 (17.1) 33 (39.7) 13 (15.7) 11.5 1.85 11.0 1.75 11.36 5.67 Mean neutrophil percentage SD Platelet count, mean cells ⫻ 10 9/L SD CSF cell count, mean cells/mm3 SD ALT level, mean U/L SD 7.8 4.4 6.9 82 40 36 68.0 10.68 160 42 9.62 4.13 66.39 12.17 186 75 41.5 62.52 55.7 74.72 43.3 87.57 69.6 122.19 Protein level, mean g/dL SD Receipt of ventilator support 6.9 1.28 5 (7.1) 6.7 1.22 5 (6.0) Enrollment from other hospitals Duration of drug or placebo treatment, mean days SD Complete treatment course received Adverse event during treatment Anemia 5 (7.1) 5.7 1.9 41 (58.6) 6 (7.2) 5.6 2.0 47 (56.7) 5 (7.1) 4 (4.8) 4 (5.7) 0 (0) 0 (0) 1 (1.2) 3 (3.6) 3 (3.6) Anemia plus an increase in the reticulocyte count Hepatomegaly Splenomegaly NOTE. Data are no. (%) of patients, unless otherwise indicated. The Mann-Whitney U test was used for continuous nonparametric data, and the x2 test was used for categorical data. Differences were statistically nonsignificant unless otherwise indicated. ALT, alanine aminotransferase; GCS, Glasgow Coma Score. a b Bradycardia with hypertension and/or abnormal breathing pattern. P ! .05. outcome) and after ⭓3 months of follow-up (late outcome). Patients whose conditions were normal or near normal at hospital discharge were considered to have good late outcomes, without regard to the 3-month follow-up data. Kaplan Meier survival curves were generated. Data were analyzed on an intention-to-treat basis. RESULTS The study was launched in April 2005. By July 2005, the ribavirin and placebo bottles had been arranged and JE IgM ELISA kits has been obtained. From August through October 2005, a severe epidemic of JE occurred in the eastern districts of the state. During 2005–2007, from July through November, a total of 791 patients with acute febrile encephalopathy who fulfilled the inclusion criteria for testing were admitted to the hospital. Of these patients, 162 patients met the exclusion criteria for testing. Of the remaining 629 patients, 577 could be tested for JE virus IgM; 161 had positive results, of whom only 153 could be randomized and enrolled. Of the 153 patients, 77 were enrolled in 2005, 37 were enrolled in 2006, and 39 were enrolled in 2007. Seventy-five patients were determined to have tested positive for IgM with use of CSF specimens, and 84 were determined to have tested positive with use of serum specimens. Twelve patients were enrolled from the other hosRibavirin for Japanese Encephalitis • CID 2009:48 (15 February) • 403 Table 2. Outcomes for children with Japanese encephalitis who received either ribavirin or placebo. Outcome Early mortality, no. (%) of patients Early mortality among 48 patients with hyperventilation, proportion of patients (%) Ribavirin group (n p 70) Placebo group (n p 83) OR (95% CI) 19 (27.1) 21 (25.3) 1.10 (0.5–2.41) 0.38 (0.09–1.57) 9/15 (60.0) 12/33 (36.4) Early mortality among patients who received ⭓2 days of treatment, proportion of patients (%) 14/65 (21.5) 13/75 (17.3) 0.76 (0.3–1.9) Good early outcome, proportion of patients (%) 28/70 (40.0) 32/82 (39.0) 1.04 (0.5–2.11) Good late outcome, proportion of patients (%) Time to resolution of fever, median days (IQR) 27/66 (40.9) 5.0 (3–8) 26/79 (32.9) 4.0 (2–7) 1.41 (0.68–2.95) … Time to resumption of oral feeding, median days (IQR) Duration of hospitalization, median days (IQR) 4 (3–8) 9 (4–13) 5 (3–7) 10 (5–15) … … Duration of follow-up, median months (IQR) 9 (3–22) 7 (3–14) … NOTE. IQR, interquartile range. pitals. Of the enrolled patients, 137 tested positive with use of the Excyton kit, and 16 tested positive with use of other kits. Once randomization was performed, informed consent was obtained for all children. All started receiving either the drug or placebo and were observed until they either were discharged, absconded, left the hospital against medical advice, or died. A total of 4 patients absconded from the hospital; all but 1 of these 4 had cases that had improved to nearly “normal,” and the early outcome was classified as good. Figure 1 presents a flow chart for patients in each study arm. Eighty-three patients received bottles coded either 10001 or 10003 (placebo), and 70 patients received bottles coded either 10002 or 10004 (ribavirin). Table 1 presents the baseline and treatment characteristics of the 2 groups. There were no statistically significant differences between the 2 groups with the exception of hyperventilation, which occurred more frequently in the placebo group. Thirteen patients received !2 days of ribavirin syrup, and 3 patients received !1 day of ribavirin syrup. There were no treatment-related deaths, and no unblinding occurred. A total of 28 patients died in the hospital, and 12 left against medical advice in a very poor general condition. Thus, the overall early mortality rate was 26.1% (40 of 153 children). Of these 40 children, 19 were in the ribavirin group, and 21 were in the placebo group. The early mortality rates were 33.7% (26 of 77 children) in 2005, 10.8% (4 of 37) in 2006, and 25.6% (10 of 39) in 2007. We confirmed that 10 of the 12 patients who left the hospital against medical advice died soon after discharge from the hospital. After we excluded the 40 patients with early mortality, an attempt was made to observe the remaining 113 patients after they had left the hospital, but only 98 (86.7%) could be observed for at least 3 months. The longest period of follow-up was 30 months. The remaining 15 patients were untraceable, 404 • CID 2009:48 (15 February) • Kumar et al. but the outcome was determined to be either normal or nearly normal at hospital discharge for 7 of these patients, who we classified as having good late outcomes. Therefore, analysis for late outcome was possible for 145 patients. Table 2 compares the outcome factors in the 2 groups. There were no statistically significant differences in early mortality, early and late outcomes (when dichotomized into good and bad outcomes), time to resolution of fever, time to resumption of oral feeding, or duration of hospital stay. If the 2 patients who left the hospital against medical advice and who could not be confirmed to have died were counted as survivors, the OR for mortality with drug would be 1.09 (95% CI, 0.49–2.42; P p .817). Figure 2. Probabilities of survival for 153 patients, according to therapy. P p .9, by log rank test. Gray bar, ribavirin recipients; black bar, placebo recipients. Figure 2 shows the Kaplan Meier survival curves for the ribavirin and placebo groups. Again, no statistically significant differences between groups were found. There were no serious adverse events attributable to ribavirin therapy. Five patients (4 in the ribavirin arm and 1 in placebo arm) experienced a mild increase in reticulocyte count, as well as a decrease in the hemoglobin concentration of 1.5%–2.8%. Four patients (1 in the ribavirin arm and 3 in the placebo arm) experienced a decrease in the hemoglobin concentration alone of 2–4.2 g/dL, which was probably due to the illness itself. The decrease in the hemoglobin concentration occurred a median of 20 days (range, 0–22 days) after commencement of treatment, and the increase in the reticulocyte count occurred a median of 3 days (range, 3–21 days) after commencement of treatment. Three patients in the placebo group but none in the ribavirin group developed hepatomegaly and splenomegaly during the course of their hospital stay. Treatment did not have to be discontinued in any case. DISCUSSION Our study found that nasogastric or oral ribavirin treatment (10 mg/kg per day in 4 divided doses for 7 days) did not affect the outcome in children with JE. The OR for early mortality and early and late outcomes in patients who received drug and placebo were close to 1, and there were no statistically significant differences between groups in the secondary outcomes. Ribavirin recipients and placebo recipients were comparable in that there were no statistically significant differences in their demographic characteristics or clinical or laboratory findings, with the exception of hyperventilation, which was more common among placebo recipients. However, after stratification for hyperventilation, no statistically significant differences in mortality rate were observed between the 2 groups. Many infections may produce an illness similar to JE, which is why we enrolled only patients with laboratory-confirmed disease. A cutoff index value of 1100 allowed us to exclude patients with infections due to other flaviviruses. The kit used was evaluated by Jacobson et al. [36], who reported a sensitivity and specificity of 96.7% and 65.3%, respectively. However, Jacobson and colleagues used only serum samples and have themselves argued that the accuracy would be better if they had tested only persons with acute encephalitis syndrome. Other strengths of the study are that randomization and blinding procedures were followed precisely. Although bottles were not coded individually, no unblinding actually occurred. Because our study involved only hospitalized patients, the patients could all be observed carefully until they were discharged from the hospital or died. The primary outcome—early mortality—was easily measurable and verifiable. After hospital discharge, great effort was made to locate survivors for follow-up assessments. The duration of follow-up after discharge varied, because enrollments occurred over a 30-month period. We expect that most of the improvements in survivors occur during the first 3 months after the onset of illness; therefore, we attempted to perform follow-up assessment for at least 3 months. Children with a good outcome at the time of hospital discharge were classified as having good late outcomes, even if they could not be followed up, because it was seen that, apart from possible development of epilepsy, such patients usually did not have cases that would deteriorate after discharge. Our enrolled patients received a variable number of ribavirin doses. However, these differences would equal out between the 2 groups because of randomization. Intention-to-treat analysis was performed; thus, once patients were randomized, they were all followed up for outcome. Another possible reason for the lack of response to ribavirin may be that treatment with the drug could not be started early enough. JE becomes clinically distinct only once convulsions or coma sets in; before this happens, the features are nonspecific. Neurological damage may occur rapidly after viral invasion of the brain and may be minimally amenable to repair. Once specific symptoms begin, the illness may have a compact clinical course, often with swift mortality. Travel to the city from far-flung rural areas would be initiated only after specific symptoms appear and could take time. It is also possible that adequate drug concentrations were not achieved. We used a dosage of drug that is somewhat similar to that recommended for children with typical viral infections [37] and for which safety and pharmacokinetic data in children are available [38]. Nasogastric or oral ribavirin syrup was used because it was thought that ethics approval and blinding for use of the intravenous formulation would not be possible in our circumstances. In a study of children with HIV infection, Connor et al. [38] reported a mean level of CSF penetration of ribavirin of 70% and found minimal adverse effects, with mean trough CSF levels of 1.5 and 3.0 mmol/L after administration of oral ribavirin at dosages of 6 and 10 mg/kg per day, respectively. It is also possible that levels of the drug in CSF may be higher in patients with acute CNS infections such as JE as a result of disruption of the blood-brain barrier. On the other hand, delivery of drug through the gastrointestinal route in a seriously sick child does not guarantee absorption. Because it was not possible to measure serum or CSF levels of ribavirin, more cannot be said about this. Effective antiviral treatment of JE remains an urgent need. Although ribavirin administered by the gastrointestinal route at the dosage used in this study was not found to be effective in decreasing the rate of early mortality associated with JE, higher doses and other routes of administration should be assessed. Ribavirin for Japanese Encephalitis • CID 2009:48 (15 February) • 405 Acknowledgments We thank Lupin Pharmaceuticals, for providing the ribavirin and placebo syrup, the consultant physicians of the Department of Pediatrics, CSM Medical University, and of BRD Medical College, for their cooperation. Financial support. Indian Council of Medical Research (5/8/7/13/ 2001-ECDI). Potential conflicts of interest. All authors: no conflicts. References 1. World Health Organization. Japanese encephalitis. 2008. Available at: http://www.who.int/biologicals/areas/vaccines/jap_encephalitis/en/ index.html. Accessed 13 December 2007. 2. Kumar R. Viral encephalitis of public health significance in India. Indian J Pediatr 1999; 66:73–84. 3. Solomon T, Dung NM, Wills B, et al. Interferon alfa-2a in Japanese encephalitis: a randomized double-blind placebo-controlled trial. Lancet 2003; 361:821–6. 4. Gould EA, Solomon T, Mackenzie JS. Does antiviral therapy have a role in the control of Japanese encephalitis? Antiviral Res 2008; 78: 140–9. 5. Prusoff WH, Krenitsky TA, Barry DW. Antiviral drugs. In: Munson E, ed. Principles of pharmacology. New York: Chapman & Hall, 1995: 1425–6. 6. Hirsch MS, Kaplan JC, D’Aquila RT. Antiviral agents In: Field BN, Knipe DM, Howley PN, eds. Field’s virology. 3rd ed. Philadelphia: Lippincott, Williams & Wilkins, 1996:454–6. 7. Ribavirin. Available at: http://aidsinfo.nih.gov/drugsNew/DrugDetail T.aspx?int_idp28. Accessed 12 February 2007. 8. Crance JM, Scaramozzino N, Jouan A, Garin D. Interferon, ribavirin, 6-azauridine and glycyrrhizin: antiviral compounds active against pathogenic flaviviruses. Antiviral Res 2003; 58:73–9. 9. Huggins JW, Robins RK, Canonico PG. Synergistic antiviral effects of ribavirin and the C-nucleoside analogs tiazofurin and selenazofurin against togaviruses, bunyaviruses and arenaviruses. Antimicrob Agents Chemother 1984; 26:476–80. 10. Lung CC, Liu Chiu, Chiang H-Y. Inhibition of Japanese encephalitis virus replication in BHK-21 cells by ribavirin. In: Program and abstracts of the 11th International Congress of Virology (Sydney, Australia). 1999. 11. Jordan I, Briese T, Fischer N, Lau JYN, Lipkin WI. Ribavirin inhibits West Nile virus replication and cytopathic effect in neural cells. J Infect Dis 2000; 182:1214–7. 12. Leyssen P, Drosten C, Paning M, et al. Interferons, interferon inducers and interferon ribavirin in treatment of flavivirus-induced encephalitis in mice. Antimicrob Agents Chemother 2003; 47:777–82. 13. Huggins JW, Kim GK, Brand OM, McKee KT Jr. Ribavirin therapy for Hantavirus infection in suckling mice. J Infect Dis 1986; 153:489–97. 14. Neyts J, Meerbach A, McKenna P, De Clercq E. Use of the yellow fever virus vaccine strain 17D for the study of strategies for the treatment of yellow fever virus infection. Antiviral Res 1996; 30:125–32. 15. Mc Cormick JB, King IJ, Webb PA, et al. Lassa fever: effective therapy with ribavirin. N Engl J Med 1986; 314:20–6. 16. Enria D, Maiztegni JI. Antiviral treatment of Argentinian hemorrhagic fever. Antiviral Res 1994; 23:23–31. 17. Huggins JW. Prospects for treatment of viral hemorrhagic fever with ribavirin—a broad spectrum antiviral drug. Rev Infect Dis 1989; 11(Suppl 4):S750–61. 18. Huggins JW, Hslang CM, Cosgriff TM, et al. Prospective double-blind concurrent placebo-controlled clinical trial of intravenous ribavirin therapy of hemorrhagic fever with renal syndrome. J Infect Dis 1991; 164:1119–27. 406 • CID 2009:48 (15 February) • Kumar et al. 19. Chapman LE, Mertz GJ, Peters CJ, et al. Intravenous ribavirin for hantavirus pulmonary syndrome: safety and tolerance during 1 year of open-label experience. Antivir Ther 1999; 4:211–9. 20. Chapman LE, Ellis BA, Koster FT, et al. Discriminators between hantavirus-infected and -uninfected persons enrolled in a trial of intravenous ribavirin for presumptive hantavirus pulmonary syndrome. Clin Infect Dis 2002; 34:293–303. 21. Mertz GJ, Miedzinski L, Goade D, et al. Placebo-controlled, doubleblind trial of intravenous ribavirin for the treatment of hantavirus cardiopulmonary syndrome in North America. Clin Infect Dis 2004; 39:1307–13. 22. Mc Clung H, Knight V, Gilbert BE, Wilson SZ, Quarles JM, Divine GW. Ribavirin aerosol treatment of influenza B virus infection. JAMA 1983; 249:2671–4. 23. Koren G, King S, Knowles S, Phillips E. Ribavirin in the treatment of SARS: a new trick for an old drug? CMAJ 2003; 168:1289–93. 24. Hosoya M, Shigeta S, Mori S, et al. High-dose intravenous ribavirin therapy for subacute sclerosing panencephalitis. Antimicrob Agents Chemother 2001; 45:943–5. 25. McJunkin JE, Khan R, de los Reyes EC, et al. Treatment of severe La Crosse encephalitis with intravenous ribavirin following diagnosis by brain biopsy. Pediatrics 1997; 99:261–5. 26. Chowers MY, Lang R, Nassar F, et al. Clinical characteristics of the West Nile fever outbreak, Israel, 2000. Emerg Infect Dis 2001; 7:675–8. 27. ClinicalTrials.gov. Treatment of Japanese encephalitis. Available at: http: //clinicaltrials.gov/ct2/show/NCT00216268?termpribavirin+and+ japanese+encephalitis&rankp1. Accessed 13 December 2007. 28. Ted case studies: outbreak of Japanese encephalitis (pig virus) in Maylasia. Available at: http://www.american.edu/TED/pigvirus.htm. Accessed 13 December 2007. 29. Chong HT, Tan CT, Karim N, et al. Outbreak of Nipah encephalitis among pig-farm workers in Malaysia in 1998/1999: was there any role for Japanese encephalitis? Neurol J Southeast Asia 2001; 6:129–34. 30. Economy Watch. Economic profile of Uttar Pradesh. Available at: http: //www.economywatch.com/stateprofiles/uttarpradesh/profile.htm. Accessed 13 December 2007. 31. Ravi V, Desai A, Balaji M, et al. Development and evaluation of a rapid IgM capture ELISA (JEV-CheX) for the diagnosis of Japanese encephalitis. J Clin Virol 2006; 35:429–34. 32. Jennett B, Bond M. Assessment of outcome after severe brain damage. Lancet 1975; 1:480–4. 33. Kumar R, Mathur A, Kumar A, Sharma S, Chakrobarty S, Chaturvedi UC. Clinical features and prognostic indicators of Japanese encephalitis in children. Indian J Med Res 1990; 91:321–7. 34. Solomon T, Dung NM, Kneen R, Gainsborough M, Vaughn DW, Khanh VT. Japanese encephalitis. J Neurol Neurosurg Psychiatr 2000; 68: 405–15. 35. Hulley SB, Cummings SR. Designing clinical research: an epidemiologic approach. Baltimore: Williams & Wilkins, 1992. 36. Jacobson J, Hills SL, Winkler JL, et al. Evaluation of three immunoglobulin M antibody capture enzyme-linked immunosorbent assays for diagnosis of Japanese encephalitis. Am J Trop Med Hyg 2007; 77:164–8. 37. Wietzke-Braun P, Meier V, Braun F, Ramadori G. Combination of “lowdose” ribavirin and interferon alfa-2a therapy followed by interferon alfa-2a monotherapy in chronic HCV-infected nonresponders and relapsers after interferon alfa-2a monotherapy. World J Gastroenterol 2001; 7:222 –7. 38. Connor E, Morrison S, Lane J, Oleske J, Sonke RL, Connor J. Safety, tolerance and pharmacokinetics of systemic ribavirin in children with human immunodeficiency virus infection. Antimicrob Agents Chemother 1993; 37:532–9.