Estimated global incidence of Japanese encephalitis: a systematic review.

OBJECTIVE: To update the estimated global incidence of Japanese encephalitis (JE) using recent data for the purpose of guiding prevention and control efforts. METHODS: Thirty-two areas endemic for JE in 24 Asian and Western Pacific countries were sorted into 10 incidence groups on the basis of published data and expert opinion. Population-based surveillance studies using laboratory-confirmed cases were sought for each incidence group by a computerized search of the scientific literature. When no eligible studies existed for a particular incidence group, incidence data were extrapolated from related groups. FINDINGS: A total of 12 eligible studies representing 7 of 10 incidence groups in 24 JE-endemic countries were identified. Approximately 67,900 JE cases typically occur annually (overall incidence: 1.8 per 100,000), of which only about 10% are reported to the World Health Organization. Approximately 33,900 (50%) of these cases occur in China (excluding Taiwan) and approximately 51,000 (75%) occur in children aged 0-14 years (incidence: 5.4 per 100,000). Approximately 55,000 (81%) cases occur in areas with well established or developing JE vaccination programmes, while approximately 12,900 (19%) occur in areas with minimal or no JE vaccination programmes. CONCLUSION: Recent data allowed us to refine the estimate of the global incidence of JE, which remains substantial despite improvements in vaccination coverage. More and better incidence studies in selected countries, particularly China and India, are needed to further refine these estimates.

Infectious diseases investment decision evaluation algorithm: a quantitative algorithm for prioritization of naturally occurring infectious disease threats to the U.S. military.

Identification of the most significant infectious disease threats to deployed U.S. military forces is important for developing and maintaining an appropriate countermeasure research and development portfolio. We describe a quantitative algorithmic method (the Infectious Diseases Investment Decision Evaluation Algorithm) that uses Armed Forces Medical Intelligence Center information to determine which naturally occurring pathogens pose the most substantial threat to U.S. deployed forces in the absence of specific mitigating countermeasures. The Infectious Diseases Investment Decision Evaluation Algorithm scores the relative importance of various diseases by taking into account both their severity and the likelihood of infection on a country-by-country basis. In such an analysis, the top three endemic disease threats to U.S. deployed forces are malaria, bacteria-caused diarrhea, and dengue fever.

History of U.S. military contributions to the study of viral encephalitis.

The viral encephalitides represent 15% (9 of 62) of the infectious diseases identified by the Armed Forces Medical Intelligence Center as being of U.S. military operational importance. Japanese encephalitis, tick-borne encephalitis, Venezuelan equine encephalitis, Eastern equine encephalitis, Western equine encephalitis, West Nile fever, rabies, St. Louis encephalitis, and Murray Valley (Australian) encephalitis are included on the Armed Forces Medical Intelligence Center threat list. This article reviews the U.S. military contributions to the prevention and control of the first seven of these.

Modification of dengue virus strains by passage in primary dog kidney cells: preparation of candidate vaccines and immunization of monkeys.

Dengue (DENV) virus strains for each of the four DENV serotypes were modified by passage in primary dog kidney (PDK) cell cultures with final manufacture of vaccine lots in fetal rhesus monkey diploid cell cultures. "Strain sets" consisting of serially-passaged DENV were inoculated in rhesus monkeys along with unmodified parent viruses for each strain. Vaccine candidates were compared with unmodified parent viruses by measuring viremia and immune responses. All except one DENV-1 strain demonstrated reduced infection in monkeys after PDK cell passage. A DENV-3 strain lost all monkey infectivity after PDK cell passage. Twelve vaccine candidates were selected for Phase 1 human trials through this selection process.

Serotype-specific dengue virus circulation and dengue disease in Bangkok, Thailand from 1973 to 1999.

Dengue virus circulation and association with epidemics and severe dengue disease were studied in hospitalized children with suspected dengue at the Queen Sirikit National Institute of Child Health in Bangkok, Thailand, from 1973 to 1999. Dengue serology was performed on all patients and viral isolation attempted on laboratory-confirmed patients. Acute dengue was diagnosed in 15,569 children and virus isolated from 4,846. DEN-3 was the most frequent serotype in primary dengue (49% of all isolates), DEN-2 in secondary and in dengue hemorrhagic fever (37% and 35%, respectively). The predominant dengue serotype varied by year: DEN-1 from 1990-92, DEN-2 from 1973-86 and 1988-89; DEN-3 in 1987 and 1995-99; and DEN-4 from 1993-94. Only DEN-3 was associated with severe outbreak years. Our findings illustrate the uniqueness of each serotype in producing epidemics and severe disease and underscore the importance of long-term surveillance of dengue serotypes in understanding the epidemiology of these viruses.

Vaccination of human volunteers with monovalent and tetravalent live-attenuated dengue vaccine candidates.

Four serotypes of monovalent live attenuated dengue virus vaccine candidates were tested for reactogenicity and immunogenicity in 49 flavivirus non-immune adult human volunteers. The four monovalent candidates were then combined into a tetravalent formulation and given to another 10 volunteers. Neutralizing antibody seroconversion rates after a single-dose monovalent vaccination ranged from 53% to 100%. Solicited reactogenicity was scored by each volunteer. A composite index, the Reactogenicity Index, was derived by these self-reported scores. Reactogenicity differed among the four serotype candidates with serotype-1 associated with the most vaccine related side effects. A second dose of monovalent vaccines at either 30 days or 90 days was much less reactogenic but did not significantly increase seroconversion rates. Seroconversion rates in the 10 volunteers who received a single dose of tetravalent vaccine ranged from 30% to 70% among the four serotypes. Similar to the monovalent vaccines, a second dose of the tetravalent vaccine at one month was less reactogenic and did not increase seroconversion. A third dose of the tetravalent vaccine at four months resulted in three of four volunteers with trivalent or tetravalent high-titer neutralizing antibody responses.

History of the restoration of adenovirus type 4 and type 7 vaccine, live oral (Adenovirus Vaccine) in the context of the Department of Defense acquisition system.

Respiratory pathogens cause morbidity and mortality in US military basic trainees. Following the influenza pandemic of 1918, and stimulated by WWII, the need to protect military personnel against epidemic respiratory disease was evident. Over several decades, the US military elucidated etiologies of acute respiratory diseases and invented and deployed vaccines to prevent disease caused by influenza, meningococcus, and adenoviruses. In 1994, the Adenovirus Vaccine manufacturer stopped its production. By 1999, supplies were exhausted and adenovirus-associated disease, especially serotype 4-associated febrile respiratory illness, returned to basic training installations. Advisory bodies persuaded Department of Defense leaders to initiate restoration of Adenovirus Vaccine. In 2011, after 10 years of effort by government and contractor personnel and at a cost of about $100 million, the Adenovirus Vaccine was restored to use at all military basic training installations. Disease and adenovirus serotype 4 isolation rates have fallen dramatically since vaccinations resumed in October 2011 and remain very low. Mindful of the adage that "The more successful a vaccine is, the more quickly the need for it will be forgotten.", sustainment of the supply of the Adenovirus Vaccine may be a challenge, and careful management will be required for such sustainment.

A model international partnership for community-based research on vaccine-preventable diseases: the Kamphaeng Phet-AFRIMS Virology Research Unit (KAVRU).

This paper describes an international collaboration to carry out studies that contributed to the understanding of pathogenesis, diagnosis, treatment, and prevention of several diseases of public health importance for Thailand and the United States. In Kamphaeng Phet Province, Thailand, febrile syndromes, including encephalitis, hepatitis, hemorrhagic fever, and influenza-like illnesses, occurred commonly and were clinically diagnosed, but the etiology was rarely confirmed. Since 1982, the Kamphaeng Phet Provincial Hospital, the Thai Ministry of Public Health, and the US Army Component of the Armed Forces Research Institute of Medical Sciences, along with vaccine manufacturers and universities, have collaborated on studies that evaluated and capitalized on improved diagnostic capabilities for infections caused by Japanese encephalitis, hepatitis A, dengue, and influenza viruses. The collaboration clarified clinical and epidemiological features of these infections and, in large clinical trials, demonstrated that vaccines against Japanese encephalitis and hepatitis A viruses were over 90% efficacious, supporting licensure of both vaccines. With the introduction of Japanese encephalitis vaccines in Thailand's Expanded Program on Immunization, reported encephalitis rates dropped substantially. Similarly, in the US, particularly in the military populations, rates of hepatitis A disease have dropped with the use of hepatitis A vaccine. Studies of the pathogenesis of dengue infections have increased understanding of the role of cellular immunity in responding to these infections, and epidemiological studies have prepared the province for studies of dengue vaccines. Approximately 80 publications resulted from this collaboration. Studies conducted in Kamphaeng Phet provided experience that contributed to clinical trials of hepatitis E and HIV vaccines, conducted elsewhere. To provide a base for continuing studies, The Kamphaeng Phet-AFRIMS Virology Research Unit (KAVRU) was established. This paper reviews the origins of the collaboration and the scientific observations made between 1982 and 2012.

Initial assessment of impact of adenovirus type 4 and type 7 vaccine on febrile respiratory illness and virus transmission in military basic trainees, March 2012.

After a 12-year hiatus, military recruit training centers resumed administration of adenovirus type 4 and type 7 vaccine, live, oral (adenovirus vaccine) to trainees beginning in October of 2011. Subsequently, rates of febrile respiratory illnesses (FRI) and adenovirus isolations markedly declined. These findings are consistent with those of a placebo-controlled efficacy trial conducted prior to the vaccine's licensure by the U.S. Food and Drug Administration. Continued surveillance will clarify the longer term impact of vaccine use.

US Military contributions to the global response to pandemic chikungunya.

Chikungunya virus, transmitted by mosquitoes to man, causes an acute illness characterized by fever, rash and striking joint symptoms. US Military investigators developed, manufactured at The Salk Institute-Government Services Division (TSI-GSD), and tested the live, attenuated Chikungunya Vaccine TSI-GSD-218. The manufacturing facility stopped production in 1994. The Chikungunya Vaccine TSI-GSD-218 development effort was terminated in 1998, and materials were archived. In 2005, an alarming outbreak of chikungunya disease began in Africa and spread to islands in the Indian Ocean and throughout much of Asia. Abrupt epidemics with high attack rates and serious, even fatal, complications were reported, and travelers carried the virus to Europe and the Americas. In response to urgent requests, the US Military offered assistance by providing non-exclusive access to the previously stored vaccine production seed materials, bulk vaccine, regulatory documentation, and reports of previous clinical trials. Five companies requested technology transfers. This experience provides lessons about epidemiological unpredictability, preparedness, vaccine manufacturing, the potential global importance of vaccine seed materials and the advisability of a global strategic plan. Consideration should be given to banking of vaccine production seeds, cell substrates, and manufacturing instructions. In view of the manufacturability, attenuation, and immunogenicity of Chikungunya Vaccine TSI-GSD-218, authorities may wish to consider this product as a possible candidate itself, as a comparator vaccine to improve upon, as a seed for inactivated vaccine, or as a source of virus or antigen for neutralization assays or immunoassays.

La influenza pandémica y el virus de la influenza porcina / Pandemic influenza and the swine influenza virus

Los estudios efectuados señalan que los desplazamientos antigénicos en el virus A de influenza aparecen según un ciclo que se repite y se va renovando. En 1973 se diagnosticó la reaparición de la cepa de influenza porcina aislada en Fort Dix, Nueva Jersey, similar a que desató la pandemia de 1918 (AU)

La influenza pandémica y el virus de la influenza porcina / Pandemic influenza and the swine influenza virus

Los estudios efectuados señalan que los desplazamientos antigénicos en el virus A de influenza aparecen según un ciclo que se repite y se va renovando. En 1973 se diagnosticó la reaparición de la cepa de influenza porcina aislada en Fort Dix, Nueva Jersey, similar a que desató la pandemia de 1918 (AU)